, . .1 3‘9“» n“ HHHIH H H "EH?- .4 V'; v :45)??ng '2 "' _.‘- z: I“: ,M' A ' h‘ ”5%;- m «3% :3 W ‘ " V": WHE‘A b';..,,u';_4’a ‘ » ‘ V4"? 4r 1 ‘14}? . "W" ‘I 4 - _ . A. 'A “#13832 ;’ iii-r" J 1:4 ‘ «14:, “at 31:: x H ‘ I t v , fire/f ‘u ‘I=P ~_\uz..‘ “ ”.3 ._r m mm 0?? HASTIQIS OUTER CURDGHARAGPERWIILK he Inflmoe or man. on the Card Gharecter of mu: {mesh Reepectfnn: emitted. to the Graduate School of the 11101113011 stete College of Agriculture and Applied Science in partial fulfillment of the requirements for the Degree of hater of Science 33' '5) , ‘ x Q I Alden P? Cole 3:— 1934 THESIS . 1.. 1" I ‘ V . ‘ .A.‘ -l: I. ' v \ ' v . l n “RIMS he author eishss to tens this opportunity to express his appreciation to 111‘. 3. In Anthony, Professor of noisy Husbndry, for his criticism of the manuscript end for asking this sort possible. no writer is grossly indebted to Dr. 0. F. Harmon. Research Associate in Deity, who so sillingly directed the planning sud woosdnrs out this in- vestigation. His guidance in tho preperstion sud mom of this pope: is also Mmelsdgod. Gratitude is expressed to D2. 0.’ S. m, Reseersh Lseistsnt in Bacteriology, and Ir. G. B. Mar, Assistm Professor of heir: Husbandry. for tho generous ass or the nostitis dsteoolleotsd by then; to n. s. n. crows, Assooiste Professor out nthemstios, for the ststistissl host-ant of. tho dsts; to lot. L. A. more. Boson-oh Assistsnt in Deity, for his tilsly edsioo throughout the period. during which this sort m carried on. 94906 ‘ '\ IN ll 0' TBIE OF CONTENTS INTRODUCTION . A m 0F LITERATURE study of Gastric Digestion Theories of Digestion Early ideas or gastric digestion Secretion of hydrochloric acid Regulation of gastric scidity 'Ehe Acidity of the Stomach Contents of Infants ' 'me empty stomach The acidity of the stomsch contents following the ingestion of food file names in Gastric Digestion Rsnnin in the manta stomach Pepsin in the infants stomach Curd Format ion Influence of scid on curd formation Influence of rennin on curd format ion Soft-Curd n11]: Digestion of ”Soft-curd” milk Tests for Curd Character Hill test Ices. test he Factors Affecting Curd Character Chemical rectors Breed influences Permanency of specific curd chsrscter Influence of stage of lactation Effect of feed on curd tension Influence of physics]. factors on time of coagulation and card diarscter The effect of various processing procedures on curd character Udder infections DISCUSSION m SUMARY OF REVIEW OF LITERATURE Gestric Digestion Soft-Curd Hill: EXPERIMENTAL WORK Object Plsn Select ion of Animels H IF use “NI-4H H @‘I‘N‘l ‘10‘0’0 10 10 10 11 15 16 16 17 17 19 23 26 29 29 Securing of samples Curd Tension Tests Detection of Hsstitis Experimental Procedure Securing of Samples Method of Pro-Heating Prior to Testing The Coagulant The Coagulating Cylinders The water Bath file lresting Procedure Experimental Data me Curd Te st ll'he Effect of Mastitis on Curd (maracter of Milk Lencocytes per c.c. and per cent chlorides IRho inflmnce of the intermittent presence of the streptococci organism The effect of a high acid content IEhe effect of fat on curd character DISCUSSIOR OF EXPERIMENTAL RESUIfl'S the (lord Tact he Effect of Mastitis on Curd Character SWEAR! Laucocytes per mot and per cent chlorides The effect of an intermittent presence and absence of the streptococci organism was effect of abnorml acidity of milk on the curd character his influence of fat content on curd character LIW CITED m TD TABLES mm Tables Pictures 30 3O 30 32 32 32 32 32 35 35 35 37 39 39 41 41 45-49 50 51-51 ' 528; 63 WWW!!!“ Soft-curd ooes' milk has been advocated as a food especially adapted to the needs of the infant. his type of ailk more nearly approaches huaan milk in curd character. however, there is a possibility that such milk may be due to a pathological condition in the udder. mtitis is a very cell-on disease of cattle. It is cemonly recognised that udders infected eith this disease secrete milk abnormal in several respects. were is a possibility that mtitis asylowerthecurdcharacter. myasnllanountofdata has been reported concerning the relation of mastitis to the character of the curd. Benson and co-vworhsrs (34) found a definite correlation between chronic cases of nastitis and curd tension. welsh and Dean (52) were unable to show a relationship between mastitis and curd character. 1% see the original object of this investigation to study the influence of mastitis on the character of the curd. Due to the lack of an adequate device for the quantitative measurement of cord character it was necessary to first develop an apparatus for this purpose. 0n the conplet ion of a satisfactory instruent the original problem was again taken up. . . . _- - ....- 1. I- ‘1 ~ L w. .. ' -'- I]. ' - _- ' - , , .. . 1 I .- 1.. a:'_.' L. . - . .J . . ' - . ' 'pe ‘ .' ' I '- -' I ... '.. . . ;. ' , ."". ' . . i.” . z.. . a... :..'-': . -. . . '. - - . .-.I .: . -, l ‘ "s :.. .. ._ f ..,. rim. 1 .1; .- '.u .-.-_ . (.. -. u.‘.':, I) ., "" H -' ' - I u . '. 2 ' n I. ' 5).: :3 '.I. i: 'n . .’.' . .1 .vv'-- 4 - . '. - ‘ . . ._ _.J.' .- -;._ _, '_ .. . .._-::.- -..- ' r:—'. ......> '. r- '_'1‘" : .1 " - :: 1. AMW'HBLIW Since soft-curd milk has been advocated as a special food for infants it seems advisable to review the literature pertaining to file digestion of milk in the stmaoh; to review the factors affecting the ourdoharacter ofailkandthe leans ofdeterainingths curdtension. m of Gastric Digestion Miss of Digestion mg ideas of gastric digestion: mm the crewman century the belief prevailed that digestion took-place in the stomach as a re- sult of the titurating action of the stomach musculatue. me consis- tency of the food being the main factor in governing gastric motility. he mechanical stimulation is effective in all parts of the stomach and acts essentially by increasing the tension in the gastric walls. It also see thouait to promote secretion of digestive Juices. the ac- tual secretory stimulus is the increased blood flow throng: the gland- ular mucosa. Reamer and Spallsnsani (13) demonstrated that digestion is a process of chemical solution rather than mechanical agitation of the food. It see also sheen that the gastric Juices are acid and capable of preventing putrefact ion. they also digest food in vitro. Prout. Tiedenann and Gmlin (13) proved the acidity of the gastric Juice is due to hydrochloric acid. Beau-out, (18) ehile working vith Alexis St. mtin concluded that gastric Juice contained food solvents other than hydrochloric acid. Later lassun (13) proved that gastric Juice contained pepsin. . x . - ' ' ' . - .. ' -. v‘ J ' ..' '. - "'- -'. 43'}. ~-'. .' -- ‘ . n‘ a ‘I' .' .u . t ' ... . ,‘ ,. ' . e' .' .'. J 'J 1 . ..!-.-'|-' I.“ .U' \ . . .,r..- . '. .I - . -v--~- ..-_-. . .. . _ -' .' - - . .- f .. .. . . . .. . - .- 3 . u I . I. - . I _‘ ,. . ' 5 L .- '. I. . . I‘ - .‘ . _ ' .. .t " .. . ~.. .. '.- P .-. .1"- - .. . J -. \ - ..'~- . - :, . . .... "fl ‘ . J. x. .. ' n.- -- -. - ‘-. .. -'. ., . - ' ' .:. ~ . . Lu . '1 an . I' .. - -I la.- .. ‘ . r ._ ._ ‘ . e" as..- \ \ w \ ,. . . ‘J" ._ _,' .\. ' . . . . ._.. n5. 3.. . ‘_.-“-'.J.: . : '! .. Q 5. .l v. _. ' .- q, 'Il .- mm (10) outlined the digestive sort or the stench as follows. (a) to act as a reservoir for food. (b) to regulate the passage or food into the duodenm. (c) to prochroe chemical and physical changes in the food. en. mi: of the stomach is given as: (a) tn. conditioned reflexes. (b) the unconditioned reflexes true the mth cavity, (c) the chemical stinlus acting iron the phylorio part or the stomach. (d) the chemical sti-ulus of the duodenal contents affecting gastric secretion. Secretion or hydrochloric acid: an. continuous secretion of hydro- chloric acid from the glandular mucosa is a normal phenomena of all sorta» brates, (13). Hydrochloric acid secretion occurs in the absence of food or psychic influences. In this case it is hnosn as appetite Juice. 'nie acid serves a too-told purpose, (a) that of digesting the food and (b) sterilisation or gastric contents. is given by Incheod (41) the appetite Juice serves the purpose of initiating gastric digestion but there is a need for additional digestive Juices to carry the process to completion. He stated that when proteins Ihich have been partially digested by'pepsin and hydrochloric acid are introduced into the stomach they serve the purpose of exciting further secretory processes. mu partially digested proteins are proteoses and peptones. ‘ Kits and Ivy (36) stated that seoretagogues are present in food or are elaborated from the digestion of food. 'Ihese stimulate gastric se- cretion on being applied directly to the gastric mucosa. the chemical composition of these secretagogues is not knoan but are thought to be protein aaterials vhich are not strongly basic in character. .L'. ”r.- .._I . n 9 t. '- s Elation of gastric acidity: me early workers believed that gastric acidity was regulated by the regurgitation of the alkaline duodenal contents. This idea has been refuted by the present day earners. Toward the end of digestion and after the acid has ceased ecabining with the food the factors controlling the acidity of the gastric contents is not neutralization by the action of regurgitated allnline materials. the decreased acidity (12) (44) is due to the secretion of a neutral fluid that contains neutral chloride. sediu chloride can be found in the stonach after the possibility of duodenal regurgitation is eliminated and. therefore, it is concluded that the fluid is secreted by the gastric glands. The hypothesis given is that the chloride is brought to the glands by the blood and sodiu- ohleride is secreted at a definite and fined concentration. A portion of the sodius chloride is left unchanged and another portion is trans- foncd into hydrochloric acid. The extent of this change governs the acidity of the gastric contents. m Acidity of the Stomach Contents of Infants as apt; stonaoh: Politser (13) stated that the gastric nucosa in the nee-born infant is sufficiently differentiated for the secretion of m1 digestive Juices. The only variation from norml is a slight- ly lover acidity and ferment concentration. filters was a lurked secre- tion of gastric Juice in 100 nee-born unfed infants. He suggested that the cause was swallowing of aminotic fluid. Grievold and Shohl (2e) reported that the gastric acidity vas due to free hydrochloric acid thich had pH value of 2.6 and a buffer value of 9.4 c.c. rho hydrochloric acid value was 4.5 c.c. . .( a e . e e I c . ~ I I ‘ . A- ‘1 ,l. . 4. an. acidity of the stench contents following the indigestion of Lee}: hrriott and Davidson (44) found that the acidity of the gastric contents varied with the type of food fed. Any pathological or nutri- tional disturbance caused a distinct lowering of the acidity of the stomach contents. They concluded that in careful infant feeding great consideration should be given the acid-binding quality of the food. According to Cassie and Cox (14) the amount of gastric acidity was not important. rIzhe normal infant is capable of secreting enough hydro- chloric acid to obtain a pH value which is optimum for normal digestive work. This optimum p}! is taken to be that secured when the infant is fed on breast milk, namely 3.75 to 4.0 Wills and Paterson (54) found the average pH of the infant's stomach was nearly the same regardless of the type of food fed. This indicated the capability of a compensatory secretion. However, Babbott and coworkers (11) found a variation in the acidity values of the gas- tric contents which varies according to the food fed. They stated that the emptying time of the stomach is directly related to the acid con- ccntration. According to Bees (25) the total acidity of the stomach is not dm to hydrochloric acid alone but also is influenced by such acids as phos- phoric acid, acid phosphates, fatty acids and acid albmins. He gave the total acidity as 20 to 60 mile of N/lo acid for every 100 mile of stomach contents. V several authors reported a p]! value at the height of digestion of 3.75. Faber (22) stated that during the first year of infancy in the average infant and at the height of digestion the pH range was from 3.5 to 5.0. In 76 of the cases studied, the gastric pH was 5.9 and 4.6. 5. Gongs (25) found that the gastric acidity value of infants fed on citric acidmilk was 3.72. Abnormal infants receiving the same food gave a readim of pH 4.15. Elias (20) reported the acidity of the gas- tric contents of infants fed on soft-curd milk was pl! 5.8 while those fed hard-curd milk was 6.2. That the difference in the acidity values of the stomach contents of the new-born unfed infant and that of the fed child is due to the buffer capacity of milks and proprietary infant foods was brought out by all the workers in this field of research. Faber (22) stated that the excess, of buffers in cows milk delays and may prevent the completion of gastric digestion in infancy. Holm and Webb (33) concluded that the greater buffer capacity of cows milk required a greater amount of gastric secretion to bring about complete digestion. They reported that the ash content which is an index to the original salt value is directly related to the buffer capacity of the milk. These workers concluded that practically the entire acid buffer- ing in milk occurs at a pH range between 5.0 and 6.0. Brennemann (8) cited the prevalent thought as to the superiority of acidified milk over the natural sweet milk. The reason for feeding this type of milk is to reduce the buffer capacity so that the pH value becomes identical with that of breast milk in the infants stomach. The additional acid also may have a germicidal effect and may act on the fats and carbohydrates. It was reported that large amounts of sweet cows milk cannot be tolerated by the infant because of its ability to neutralize a considerable portion of the gastric acidity. It is recom- mended that the addition of 0.5 to 0.7 per cent of lactic acid to the milk will overcome this difficulty. . . . § . v 0 . . , . . . 4 . . \ 4x I a .A w ,. 'I .I n l I v . . .c V . . . .1. D . . . l . .,. J u . . s . . I. n .‘ ., . _ . ,1 II. V a . n m , . . t s v; . i . a . . .. . , a. . \ u . V c 1 . J. . . u [A .u . \. I D , .\ I . . . i . IA 4 . a! . , . A. . . i , . l u I A ‘ . i _ x . ,L o . ‘ . r l J '.a I I O ‘_ v as .o I . a x l s. 1 D .b\. .,. .. . . A - . 1 . s . . O . . . v c , _Ia _ a . . o . . t . r u . . . . . a U . . . ¥ c . I J . f . . ‘. . a , I v u a a s . c d if, ,1 u .6. lscherish (9) in 1899 found that covs' milk will bind two to three times as much acid as human milk. Fresh covs' milk has a greater acid combin- ing capacity than does old milk. He calculated that one liter of cows. milk requires three liters of digestive Juices to complete digestion. rho stomach of artifically fed infants showed a higher organism count than those fed breast milk, thus bringing out the germicidal effect of the additional acid. Brennemann (9) reported that 58 per cent of the buffer capacity of cows' milk was due-to the poteins and 42 per cent to the minerals. Since human breast milk is lower in these constituents than is ccws' milk there is a possibility that cows milk may require a greater amunt of gastric secretion for digestion. 2e msymes in Gastric Digestion Bennin in the infants stomach. The enzyme rennin is present in the infants stomach at birth. Its function is the coagulation of milk in the presence of hydrochloric acid. According to ness (2'!) it is in the form of a proferment and is most active at a hydrogen-ion concentration of a pH 6.0. Wang and Wood (50) found that rennin alone would not precipitate the casein from human milk. Upon the addition of an acid the rennin co- sgulated the milk very rapidly. However, the ensyme readily coagulates cows milk without the presence of an acid. Its optimum activity occurred at pH value of 6.53. Faber (22) claimed that the milk is curdled by rennin before it has time to reach the acidity of the gastric contents. 7. Pepsin in the infants stench. This enzyme is found in the stomach at birth and increases in amount until the infant reaches the age of four months. After this period the mount remains at an approximte constant figure. (26) The function of this enzyme is the partial digestion of proteins. The products of this partial digestion are protecses and peptones. Pepsin performs its work most efficiently in a medium of pH 2.7 (26) According to Hess (26) peptic digestion takes place from the periphery of the food particle. W factor which increases the surface exposed to the ensymic action will have a tendency to hasten the digestive process. curd Formation Influence of acid on curd formation. Brennemann (8) found that the addition of an acid to milk in vitro pre-coagulated it and that it did not recoagulate after being ingested. He reported that a finer softer curd was formd from the acidified milk than from non-acidified milk. Gongs and Templeton (23) found that the curds formed in the infants stomach with whole citric acid milk were uniformly snail. mrriott and Davidson (44) favored feeding acid milk for the same reason. Hewever, they later concluded that lactic acid milk required as large an amount of digestive Juices to digest as did unaltered milk. Wang and Wood (50) reported that acid alone would not coagulate hman milk. However, in the presence of rennin precipitation inunediately occurred. The same workers found that there was prompt precipitation of casein from cows' milk by the addition of an acid. The optimum pH for this reaction was 4.61. .1 r I \ -...;1:.\. 2'..- . 1.1:. “Ll -.r ...-. a 3. he evidence presented by Boswrth (5) showed that the hard protein curds sometimes found in the stools of infants were not the result of nutritional disturbances, but were caused by an over supply of soluble lcaloim in the milk or an excess of acidity vhich dissolved the normally insoluble calcium. Influence of rennin on curd formation. The coagulation of milk was reported by Hess (26) as being the function of the enzyme rennin. He stated that human milk was less readily coagulated by rennin than was our milk. The presence of an acid or an acid medium is required for the activation of the ferment. Faber (22) gave the pH values of 6.0 and 6.4 the optima activity of rennin. He, therefore, concluded that milk is curdled in the stomach by the ensymic action before it has time to attain the hydrogen-ion con- centration of the gastric contents. Harmarsten (40) assumed the formation of two substances by the action of rennin on milk; These are, (a) the insoluble curd and (b) the whey soluble proteins. The factors influencing this actiOn are, (40) (a) the presence of soluble calcium salt, (b) the reaction must be neutral or acid, (c) the acid dissolves. the insoluble calcium salts thus increasing the amount present, (d) the acid has an activating effect on the ensyme. 'l'he dilution of milk decreases the amount of soluble calcium salts and, there- fore retards the coagulating process. Temperature has a lurked effect on the rapidity of reaction. Body temperature scans to be correct for the greatest activity. The heating of milk above 160° for a considerable length of time unless for less rapid coagulation by rennin. Von Slyhe and Bosvorth (40) have verified the hydrolytic splitting of the casein molecule forming paracaseinate as a product. Paracaseinate . , . '1 ._.I. O I. e'. .. l ' I u .1... . I‘. .I .. ( _- \. a I . I - .l I ' _ L L .. . .. .i ._ .1 r. ' a I. u l I “LL. 1 v . . _ [I . ' A - -_ = . . . - . . r, . . z .- ,.- H . . \. __ . . . .. . r .- . ' . , ' - . a .. . -... l .. .I 2- -. — '— -. .~ -I - . . - r .. .. u _.. u .. .'. _ . . 'J ._. ' . ‘ _. 4: . r... I“! '.- 7; . .- . ..' . r _ _ . - _ ' ' - h J. L .'u—JI. " - _.:.. - -: ---..'-., . :2 ; .. . ' . .‘ -. ' - -- _ -- . . I v 4-. - - -' " In . - '-. f . .. I. h_. .a. I, '~-' .- I ' - 2-1 - .'.. .: -'.' -r. ;.- .'. ~ ‘.'. I. ., e; L-‘.-'. ' : '. H' . '.' . ' -:".- ' I ‘.‘. .-! ' ' . 3. . . - -' . ' e - ~ .'. .- .. -- - - _' -.. .-:- , .. . . .‘ .. . ' ..... . " '. :' .. :. :: .:.. . in. i. l . ~ . { .‘. . . H" 1: '2". I: .. '. ' .. ' .‘.. £11555- . L— .' .- . H .. " :. "-. I -l u '- n .-.. .. .-.. j- ... . ' .. - . r f~ . .. . ' ‘ - H'- .. ._...-.. ._-..... ' .. . .- I" ._. _ _ . r' . ,,_. .. .. . .. -. - . K -' .' .1 1'..- .‘-’ t. . .L ' at ' I ‘ 'C: ‘o.- - . ‘ \ . . _. \ :1. .' ' l" . . ' . ', . . ' ... a ‘5' .-....| - .J . 1-.' . ' .- ' . - . _ _. . . ... .J-.. . "I. ..‘- '.' - ‘ ‘ .'. u, a u ' ' - u ' I . 1-. I I ., '. I. '. ‘ '. .‘- : ' I‘-'- .'.-.-'.-_.. V) '- - ' . '. . . r '.r ,_ . . ., -,l --.L ' . \- '. ' - . . -r --. ' .. .r u, or -. - . .-.~ ' a. ._u “1” La. .'. ._ . ._ _ I _ .- t" . .. -. . .) .- _ _ . '. t‘ . .'_‘.'_' "I \- .. .' ' ')- .'.. . h; . . k"' '. (I '. .5 "' ' . _ _ .: '. n \._ I, '- I ' e "s w . :., . ._. » ha; .- .' u .. ‘ '1) .‘. " .‘ . . =. . _.' .'l'. ‘ . . .‘ . .. ..l I . .- -e I -' l - ml 9. is soluble and is precipitated as by the action of the calcium salts. boy found that the milk from fresh cows use much easier coagulated by rennin than was milk from cows which were nearly dry. SOFT-CORD MILK Dgstion of "Soft-Curd” [ilk Rape (19) stated that milk upon entering the stomach was a liquid but is rapidly changed into a solid by coagulation. After solidifica- tion digestion takes place from the periphery of the mass. Any factor which tends to make this mass more porous or loosely constructed shortens the digestive period. He also found that soft-curd milk was digested in one and seven-tenths to one and sign-tenths hours. llilk with a relative tough curd required a digestion period of two and three-tenths to two and eight-tenths hours. Adult dogs were used in these trials. This shoved that by doubling the curd tension of the milk fed, the length of the di- gestive period increased 30 to 60 per cent. Work carried on at the Department of Pediatrics and Child Medical Survey at Bellevue Hospital by Elias (20) showed no material advantage of soft-curd milk over hard-curd milk. Elias reported that in the series of babies fed soft-curd milk there was indigestion in 17 per cent and that five and nine-tenths per cent of these infants died. In another series fed certified milk there was gastro-intestinal intoxication in 24 per cent of the cases with 15.7 per cent deaths. Elias (20) also reported that 16 per cent of the infants receiving soft-curd milk showed large firm curds in the stomach. The curds formed by evaporated milk were comparable to those formed by breast milk. He concluded that soft-curd milk does not prevent diarrhea and vomiting. 10. me infants receiving soft-curd milk required a higmr caloric intake I than those receiving other milks. Further work at the Bellevue Hospital (1) in which 50 minutes after feeding milk to infants vomiting was induced. Milk of average curd tension was fed to 27 babies. In 30 minutes 21 had hard curds in their stomachs. six had soft-curds and in no cases were the solids of the milk liquified. Soft-curd milk was fed to 54 infants. After re- gurgitation three showed liquid contents in the stomach. Thirty-one had soft curds and nine showed hard curd formation. Milk with a curd tension of 26 grams was digested in 85 minutes. Milk with a curd ten- sion of 51 grams required a digestion period of 103 minutes. Tests for Curd Character Hill Test. In 1916 Hill (29) reported a quantitative test for curd tension determinations. The apparatus consists of a specially designed curd knife and spring balance. mm knife has a three-eighths inch center which is tapered at 60° to fit around a one-eighth inch stem. The stem is six and one-fourth inches long with a one-fourth inch loop bent at the end. There are ten radiating blades soldered into slits in the large center of the stem. ‘lhess blades are cut from one-twentieth inch sheet brass and are one- eighth inch wide. The sharpened edge of the blades being placed on the upper side. The knives weigh eighteen grams and do not vary more than a half gram in weight. A specially constructed spring balance was used. It has a capacity of 250 grams and is calibrated to offset the weight of the knife. An sight ounce mayonnaise jar was used as a coagulating cylinder. 11. me coagulant consists of a mixture of three parts of 0.6 per cent of 1-3000 dry scale pepsin solution to one part of 37.8 per cent of dry gran- ular calcium chloride solution. The milk is tested as soon as possible after drawing from the cow. Duplicate 100 c.c. samples of thoroughly mixed milk are placed in the Jars. they are then imersed in a water bath until a temperature of 35°c is reached. The knives are then placed in the milk to be tested and ten c.c. of freshly mixed coagulant is added by moms of a rapidly flowing pipette. The end of the pipette is enlarged to allow for this rapid emptying. While the coagulant is being added the milk should be agitated by means of a cir- cular motion of the Jar. The amount and uniformity of this agitation seens important. The Jar is then returned to the water bath for a ten minute coagulating period. At this time the book of the spring balance is attached to the loop of the knife stem and by a slow and even tension the knife is drawn through the curd. ihe force required for this pull is read directly from the scale. Hill (29) reported that with duplicate samples of soft-curd milk the variation did not exceed five grams. Hard-curd milk samples could hot be checked within ten grams. Milk which showed a reading of from zero to twenty grams was classed by Hill as "soft-Curd". Those milks above this upper limit were hard-curd milks. Iowa test. Espe and Dye (19) used a modification of the Hill apparatus. The knives were made large with the blades extremely sharp. Their coagulant consisted of pepsin alone. Their readings were made in a series of three minute intervals in order that they might get the maximum force required. __ a'a‘ -. . -. . - . . '.-r. , . 12. 33 Factors giboting curd Character: Chemical factors. Allsman and Schmidt (5) found that with other factors remaining constant the curd tension increased with the amount of calcium chloride added. The product of the coagulation period in minutes and the curd tension was a constant. Ellie calcium ions had no specific effect on the coagulation except that conditions were made more favorable for precipitation. Hill (52) reported that Holstein soft-curd milk contained 0.65 per cent ash and hard-curd milk from the same breed contained 0.74 per cent. Espe (53) found an average ash content for soft-curd milk and hard-curd milk of 0.57 per cent and 0.80 per cent respectively. Hill (53) and Espe (55) found that soft-curd milk had a relative- ly low casein content and Weisbery and coworkers (55) reported a much lower concentration of casein in soft-curd milk than in hard-curd milk. The following table from their work shows these variations. Table I - The influence of casein on the curd character. lee , s d ens on g : ase , : ension per cent : grgs : : per cent : grams 1.85 28 g 3 2.91 75 2.10 28 z 8 3.07 110 2.17 30 8 3 3019 120 2.17 58 3 3 3.32 85 2.24 22 : : 3.61 140 2036 52 8 3 3.71 163 2.&9 58 : a 4.25 190 2.56 40 : 8 They concluded that the correlation between casein content and curd tension was not ideal. Welsh and Dean (52) found that soft—curd milk contains two per cent or less of casein while hard-curd milks contained 2.6 per cent or more. A curd tension of 35 grams or less was classified as a ”ft-curd milk and 15. all milks testing over 60 ens. of curd tension were classed as hard-curd. 'eisberg and coworkers (55) reported a relatively low concentration of whey- proteins in the soft-curd milks. The ratio of casein to whey- protsins was also, in general, lower. These workers added whey-proteins to milk and found no effect on curd tension other than that exhibited by ordinary dilutions. In these trials the casein content was kapt constant. Hill (50) found that milk: with a high fat content was more likely to have a hard-curd. However, he reported that some high fat testing cows gave a soft-curd milk, while some low fat testing cows gave a hard-curd milk. He also reported that the mere presence of fat in the milk had a softening effect on that milk after it is coagulated. Hill concluded that the removal of fat made the curd harder. ‘me fat flobules tended to prevent the curd particles from coalescing together with the same degree of toughness as uhen the fat was removed. The higher the fat content the greater the effect on the curd character by its removal. Weisbery and co-workers (53) presented the following data. Table II - Concentration of fat in relation to curd character "m 3—75}? x : fit : Curd per cent : tens ion 2 : per cent : tens ion 3.3 3? s: 5.6 as 5.2 59 s: 4.2 30 3.4 40 : s 6.8 110 5.0 30 z 2 5.9 65 4.3 30 g 7.3 85 4.0 32 z: 5.4 75 5e4 30 8 8 6.8 70 3.6 25 : 5,3 50 3.6 40 : 2 7.8 55 4.5 45 3 5.8 125 4.3 58 z 3.8 102 4.2 28 g 4.2 102 14. These investigators found no direct correlation of fat content to curd character. The distribution of the fat undoubtedly played an im- portant part in determining the curd character. It was assumed (55) that the size of the fat globules would exert an influence on the curd tension. Photomicrcgraphs of the fat globules of various milks failed to prove this. The following data are given by Espe and Dye (19) to show the effect of dilution on curd tension. Table III - The influence of dilution on curd tension Dilution : A3551 : morectical milk to water : curd tension : curd tension 1:0 117 117 4:1 71 94: 5:1 68 88 2:1 51 78 3:2 46 71 1:1 26 59 1:2 1 59 1:3 0 29 1:4 0 23 There is no correlation between dilution and curd tension as reported by these workers. In whey dilution work carried on by Weisbery, Johnson and MoGollum (55) it was found that the whey from soft-curd milk had the same effect on curd tension as the whey from hard-curd milk. As with water dilution the curd tension was lessened by dilution with they. Weisbery and co-worhers (53) studied the influence of hydrogen-ion concentration on rennin coagulation. Sodium hydroxide was added to nor- mal milk to render it alnline. Hydrochloric acid was added to another quantity of milk. The effect of these additions on the curd tension of milk is given in the following table. r i I .,. .. . :_ r ... __ 's . l - I ..‘ l I .i._ '1 .. . .. . C 'I' l.‘\. 1.. f - ' - .‘.. -_ s.-._ .; ---..._ -... .2 ' . f . '- .- '. ' -.-. I . r . ~ -. .'l .l', -\ 15. Table IV - rL‘he effect of abnormal acidity on curd tension 3 Initial : if after : 0?;er E111: : E test : tension lOOlT/lONaoH 25° 3909 Milk 7.20 5.88 12 untreated milk 6.75 5.8 24.5 2 c.c. N/l Hcl 24° 00°. Milk 6.55 5.54 44.5 4. c.c. 13/1 Bel 250 c.c. Milk 5.95 5'056 6405 They concluded that changing the pH of milk by additions of alkalies and acids has a great effect on the curd tension. 11: was reported (53) that the citric acid content of individual milks varies from 0.07 per cent to 0.53 per cent. The citric acid content of a given cows' milk is nearly constant. There was no correlation between curd tension and citric acid content. Ieisbery and others (53) found that the concentration of lactose in average certified milk was 4.7 per cent. Hill (58) reported that soft-curd milk had a lactose content of 4.52 per cent, while the concentration in hard-curd milk was 4.68 per cent. Breed influences. sin (30) (31) working largely with Holsteins and. Jerseys found that the lower testing breed more often gave a milk which showed soft-curd character. 'During trials over a six months' period the average curd tension of Holstein milk was always below that of Jersey milk. He reported that soft-curd character was not entirely limited to the lower testing breeds. Some Jerseys gave a soft-curd milk and some Holsteins a hard-curd milk. In later work Hill (51) found that 1.2 per cent of the Jerseys tested had a curd tension within the range of zero to 30 grams. There was 6.6 per cent of the Holsteins in this range, also 2.6 per cent of the Guernseys .H. |-1w \ .w ‘ ‘. - . - . I. .- . .,.- .. . . 4 J I." U . . . . .. ...\. ~- 3— -' wrr-,‘ L. 1‘5. and 6.66 per cent of the Ayrshires were classed as soft-curd producers. curd tension determinations were reported on 2,000,Ayrshire cows. It was found that 77.16 per cent of these cows produced a milk which tested under 60 grams of curd tension. 9318 next ranking breed had 54.31 per cent of cows which produced soft curd milk. Less than one per cent of the Ayrshires produced milk which had a curd tension of 100 grams or more. The percentage of cows from other breeds testing over 100 grams varied from 81.4 per cent to 33.03 per cent. Strickland (48) found that as many as 25 per cent of the cows in Holstein herds were soft-curd producers. The next highest breed had a much lower percentage. Some large herds of the higher testing breeds failed to have any soft-curd milk producers. PGMOM specific curd character. Hill (30) found the curd character cf an individual cow was permnent within limits. When the milk from a certain cow was tested each lactation period a marked uni- formity was found from year to year. The milk from the first part and last part of each lactation period was not used in these trials. Influence of stage of lactation. Bill (30) found that for a period of one month or six weeks following freshening the milk from an individual cow had an abnormally harder curd. A soft-curd cow does not necessarily give a hard-curd milk during this period. It was found that milk from a cow which normally tested 20 grams of tension usually ran as high as 40 grms during this period. Toward the end of the lactation period the curd character of the milk became harder. There was in some cases a softening of the curd which was believed to be due to an abnorml condition of the my gland (30) e 17. Alleman and Schmidt (3) found that toward the end of the lactation period the time of coagulation increased while the curd tension decreased. After freshening the milk showed more rapid coagulation and an increased curd tension. There was a tendency for the curd tension to decrease until it reached the normal figure for that individual cow. Effect of feed on curd tenfl. Allasau and Schmidt (3) found no inflmnoe on the coagulating time or the curd tension of the milk when 150 grams of calcium carbonate was fed per cow. Kill (30) reported that except for sudden changes of ration the curd chracter of the milk is independent of the nature of the feed given. than the feed changes caused an abnorml fluctuation in the fat content of the milk there was a liloe fluctuation in the curd tension. Pasture and feeds of high water content caused the production of a milk with a lower concentration of solids and also a lower curd tension. Influence of physical factors on time of coagulation and curd character. Alleman and Schmidt (3) found that coagulation occurred with greatest speed at 40°C. Above and below this temperature the process because slower as the change progressed. The curd tension decreased as the time of coagulation deereased. These workers demonstrated that the speed of coagulation was not in direct proportion to the temperature. The rate of coagulation was relatively lower at higher temperature than at lower temperature as shown in the following table. Table v - The influence of temperature on coagulation Temperature : :JV-ariation from interval in : Temperature : average dflees c. : Coefficient : h1g1 ‘ low 20-30 2.09 0.16 0.09 25-55 1.75 0.11 0.09 30-40 1.40 0.03 0.09 35-45 1.09 0.26 0.09 40-50 0052 0024 0.27 130 The temperature coefficient between 30° and 40° showed the least variation. it 20° to 30° the tanperature coefficient was 2.09 which showed that coagulation occurred 2.08 times as quickly at 90° as at 20°. it 55° to 45° the coefficient was 1.00 with the limits showing little variation. They concluded that the higher tenperature accelerated coagu- lation and gave a higxer curd tension. The increase in curd tension was directly woportional to tm increase in temperature. At 45° the coagulation was slowed and there was a decrease in curd hardness. This was due to the decreased combining power of the casein and the rennin or the greater motility of the casein particles under the in- fluence of heat. Some soft-curd milks (3) showed a diminishing curd tension at 39° and that the tension at 41° was lower than at 35°. other milk: showed a maximum curd tension at a coagulating temperature of 42". In experimental work by Alleman and Schmidt (3) it was shown that the curd became harder from the moment of coagulation until the reading was taken. It was in direct proportion to the period of ob- servation. This was true within certain limits as the tension event- ually reached a marinas. If the curd tension is known for a given coagulating period it can be calculated for any other period. The increase in curd tension with the time of coagulation is shown in the following table. I Table VI - The influence of coagulating time on curd tension : one a two a five : 803611 3 mill; 2 min; : min. : min. Curd tension 13 58 64 84 Ration 1 2.9 5.0 6.5 . .a..- I" ‘w e '- I .. . .. . . '- .i. :\ '1 . . . . . ',. l n\ . _ r . . _ .. .. -. s I - ' .' _‘- .. .-.r: ‘ - . I f \._~ g.. ._.. ‘ - J‘- 19. llleman md Schmidt (3) stated that if coagulation is a simple splitting of the casein molecule then the effect of agitation is difficult to understand. However, if shaking breaks up the micellular structure then the physical character of the curd is altered. hey accused that the casein exists as indspmdent particles possessing sur- face energy which is destroyed by the action of rennin. The degree to which the energ is destroyed controls the coagulation. These points were proven by these wcrbers.‘ If the agitation was violent and prolonged large amounts of rennin were used in order to cause coagulation. Hill (30) reported that prolonged agitation of the milk while the coagulant was being added greatly affected the curd tension. 9111s tends to agglutinate the curd causing a separation of the insoluble curd and the whey. Little or no agitation would not properly mix the milk and the coagulant would result in uneven coagulation. The effect of various processing procedures on the curd character of milk. Hill (29) quantitatively measured the change in curd tension caused by preheating the milk. He found that heating the milk above a temperature of 92°C decreased the curd tension considerably. This was the maximum temperature that could be obtained in a water bath. The average curd tension was decreased 69 per cent. A natural soft-curd milk cosgulated slowly under the influence of preheating as shown in the following table. .- .4. :... _. .-....L'I'.‘~'O-'.‘ .‘.I “-...-1| .L-‘U‘. n. d .r.'fi."- Muslin .-: :12; L:'--"'.“i.:' r:- .i: ssh-:5 '.-.'- :g-uiroiiqa '1'": .'.; -- L. 2:! 2.1m: 03 d‘imfit'flh .22.". . '1. .1: :L .‘.-2'; '.-o -".' .'2';;,\1; Bil-'CBGU'Ii-‘a '._ ': -- '- or 3-1:: Ama- .'.-..'}. .-.;- 5.3:..‘2249 .--..':..--.:---.:: :-.-’.' ..-' nit haulage u." '.=x-: '- .-‘- '-"_.- - .. ' 3'1".) :J'L'j- .'." -"__.-'.. v} '15.“; 955". . ' ':-. .". .fic-j:a':.~.:u.:..c.:; "5.x:- -..- .. -...3 . :iain’r ' . . - .- - -' 9- . - E--- - ' . - '- " . '. . -. . ... .- . -._- .‘--.-. Jae-la. v 11.!!! 1:1... . -..--'- av-.. .e'1.. .r mum-1.. 9'“. ' '- . ' - -. .'. . E. . - . - . . .. . .. ..u .. v. c. -...' .5... z..-; c o-.t:on:s a‘g'xei -' . . ' . r - ~ -. -.. -. . .r_ _ __ .’.. ‘ r . . :- .- 2. .- .. -0 :.--.-:‘ -:. _-,.rs .-.~J .r.--.-..-'fi_= 3.1-. .'.: -. m a. {3-.- .L.‘..'. ' -. - ,. - . . .'.. . . -:-. .z.‘ . “.22-. 5.. .- ' : ..‘s,- .. . - -.- r. .. ..wlza,..aa . . . - ' _' . . - -- - . - u .. H '-‘--.""' ' _-.._"_'. _.'. 2. .-_'.'n.._ Lia-z...-' .'.'- .-.- '.G 1'..-J".\ .-'. -(-_-. !: :~. ',.€-.?..f_|.!‘.. .-_ .'. J. .- --: - .‘n. .'.-121:5: 03' ' ' - ' - - ' . . . “ -' . n . .- . -' . '= - .' .I ls.:' :1. . . ' L:.'.I- - —' ' ‘.._ a "0'1' I: “In. ' I: O‘.’ .'--2' 3-1 .I. . Ua. ‘J . I: - _ ‘ “Edi-1' Ell-1|} --r-' -)..\ '. . i) ..1' . - |-'1, fl- 1: - ---- - ' .I‘..' .. ': . 'r-. - -'r- .-_ . :' HI 9 I! U 'u..u ."d . '3 '-_r_ .w'. Unit"):- '_ ‘.’-. . .-.J..s . o ...‘..' .. ._ .. .. - I ' 'l . _ ' - .' .. , d' - — - - ' ‘ - I '.I . - .. J.'.l . I. .U 1-:0l 3. . own..." .. IT I:- - ”.'l. .5 ' ' - . .. -' . . .v' n a I - .‘ e' ' I ' ' '. u" ' . -... e (-1: _‘_!...4-.U:I 51-” .fl' .5 ’J'AIAI :3. .- 9-.1. .1'.”‘!"..,-. - _ . .. .' .' \— . .' {f-Z- J I ’: ' n,. " I 2 .- . {.‘.-n. ' . .-' .--.- -L-: . - - '1 ' r I. s H" \. ' _ o n J‘ . .. I ~- J! _..L u..-' sun. I. .'.L. .. -a. I..-I I’l. .. "n. J. - . t . - . . , .. - rid. L”:- n' n -' .'. J'I. v'} . " ' s_ I ' a I. n- .I I. ;J .u wr- i.‘-ou “Lil ' . .9. I .' . .:-._-_n - :'.-.- 'Cl...-J 1. {s ... Table VII - the effect of preheating on the curd tension of milk mated. Elk : Heata HIE Cow : curd temigg : curd tension 48 194. 68 44 57 so 54 179 56 58 151 46 45 167 66 136 22 6 50 14.2 46 148 78 12 156 26 4 144 33 6 156 45 4 189 60 15 59 146 67 158 61 8 52 111 34 47 55 7 Later experiments by Hill (50) showed that pasteurization of milks tends to lower the curd tension. However, in no cases was the curd from the pasteurized milk as soft as that of the corresponding boiled milk. Corbin (l7) referred to the softening effect of heat on the curd character of milk. Adger (4) reported that soft-curd milk can be produced by home- genization. This process reduced the size of the fat globules and more completely dispersed the casein particles. These particles were in such a fine state of aggregation that coalescing mid clumping were prohibited. Hill (31) reported that the limited number of experiments at the Utah Station do not Justify the production of soft-curd milk by the use of the hcmogeniser. Lyman and coworkers (38) found that when cows' milk with an aodity of 0.16 per cent calculated as lactic acid, was contacted with zeolites, , three to five per cent of the total calcium was removed. If rennin is 21. added to this milk a dense coagulum is formed. If the acidity of the milk is brouQit to 0.3 per cent am then passed over a bed of seolite the removal of calcium is a much larger portion of the total. Table VIII - The effect of a changed acidity on calcium and phosphorus removal : Acidity as : WeIEE-I o? : EEIcIm : ficspfiorus lilk : lactic acid, : moist seolite 3 removed : removed 3 per cent : : per cent : per out 600 0.16 180 greensand 5 17 600 0.16 90 crystalite 3 14 600 0.50 180 greensand 15 24 600 0.30 90 crystalite 22 22 The milk from which 14 per cent of the calcium had been removed curdled with rennin. The removal of 22 per cent of the calcium was sufficient to inhibit rennin coagulation. It was concluded that milk vith a low acidity had very little of its calcium in ionized form. If milk was treated with aeolite, boiled and inediately cooled to 38° a soft-curd was formed with rennin. Allowing the boiled milk to stand for several hours caused a rearrangement of its salts and coagulation occurred with rennin. milk that was acidified with hydrochloric acid and then passed over zeolite coagulated on boiling. If the seolite was treated with equal parts by weight of sodiuu chloride and potassium chloride there was very little change in the sodium-potassium ratio. The removal of phosphate from the milk by the base-exchange silicate was caused by the presence of calciun ions or other divalent ions. The ordinary revival of the zeolite by neutral solutions of the alkali metal chlorides did not remove the phosphorus from the used seelite. The calcium and phosphorus was not removed from milk by treating it with this solution. . h I.) . :. ..- : .' l. I I . ‘5 . L: . t' - IL. ..;| ,.......-_.. '. ,'.'..-_: . . : .'. ..If. ; .33“).- ,. :I’ ..._...... .-. .- . I - . , ._ . . ..I. ‘ .| I "’- .. ..' . ' ._ . .'.J'. .: -'.. : "3-" ___'._ .':. _.' . . "' l I . . du- ... .I ." . ' . . .- . . a. ' _' .' I s .'.;.'.. . -- ' ' - . ',. I. . .. \. - ... . ' I .: m- _ a '_ .- s n I' I - f. . .' .".' .l' Table 11 Tint greensand : Revival :Mr cent : fir cent grams 3 process : c.c. : ca removed a P removed on . Nae 5 180 new a. Reel 600 16 25 m base-exchange process inhibits rennin coagulation because the amount of calcium present in the treated milk is not sufficient to form the calcium paracaseinate clot. They oonolmled that at least 20 per cent of the calcium must be removed in order to prevent rennin coagulation. Both ski-milk and wholemilk were used in these trials and gave comparable results. Courtney (16) found that very small and compact cords were formed fraa pondered milk. This milk was dried by the Roller process. No quantitative measurement was made of the curd tension. Hill (50) reported that when the milk left the evaporator 50 per cent of its water content had been lost. This milk gave approximtely the same curd tension as the raw certified milk. Diluting this milk with water to its normal consistency gave a curd tension equal to boiled shole milk. He concludedthat the change in card tension was dm to the heat rather than evaporation. After the milk was canned md sterilised for 30 mimtes at 234°]? the curd character was materially altered. If this milk was diluted to norul seine the curd tension was reduced about 50 per cent that of original raw milk. Sweetened condensed milk which was not sterilised had about the same curd tension as unsterilised evaporated milk. ._. A a 1 . . . . . -......---........................... : ..-.' .-(ui " _ :.| !_-‘.. : -_._, 1' .' _ - _. . u u . .‘. '- |. f 1‘: .‘. --:' .I_ -::J'.( 1-; ‘I‘ [ll _ .._ .n.. h . ..' U"r'“ , . . .-. - ,- r- 'n. a --- ‘ -- . . . .. J. \. l - la .'. . . .. - ....--—.s- -. _. - . o - '.. ...' ' ..' '.' -\'.' . '-- ‘1... H" . '- " . . -. . .'i' a; :" . . t. ' I a I . i . . l_ as , . f ' , '. . ' - . - .. a .- .- . I n. ’ . .. ‘- . . .1 -' '. . " .. ' . . - _ I” - l.v' .' y' ;_ . . . l‘ f _" . v 7,, _. .. ._ .- - _ .. ._-...... . a - .'. -" l .. I ..L - '.'.'|_ . . . . .-\ I . - .- . .. -. 1., -. . n _ .. ... .. . l. '- . -. - I .. _- ... . . . . . .- ‘ .. .‘. 1 I . . s. .n' I'- .' - .I . - . ‘ . . . _ ._ . ._ . . __ - .. . . ' .- r. . I I" ‘ .' E - - u u. . . I.‘ - -1 tHCU - - . .‘- .... ._. ,- : . . . ... ..o .- . . C .‘- .., .t.. , . - a. O . I.- .- 'I \.\ . 25. adder infections. Hill (29) (50) concluded that large variation from normal curd character with an individual cow was usually caused by the production of abnornl milk. This might have been caused by mechan- ical injury or by infectious disease of the my gland. “slams (49) found a decrease in titratable acidity and an in- creased pH value in milk produced from an abnormal udder. The milks of reduced acidity coagulated slowly or not at all with rennin. The addition of calcium chloride or carbon dioxide to these milks reduced their coagu- lation time. Welsh and Dean (62) used the brom thymol blue test, the chloride content, the leucocyte count and the pH value of the milk in detecting mastitis infection. A leucocyte count of 5,000,000 or more caused a lowering of the curd tension of the milk. 1 lower curd tension was shoun by milk with a pH value above nomal. The infected quarters produced a milk which was lower in casein content than that milk from normal quarters. a low concentration of casein correlated with a lower curd tension. mess workers concluded that a soft—curd milk as denoted by the 3111 test does not necessarily come from infected quarters. Udder infections caused a lowering of the curd tension of the milk under that which was normal for uninfected garters. Ems production of soft-curd milk by infected quarters was due to a lower casein content. Henson and co-worlmrs (34) found a distinct correlation between mastitis infection of the mammary gland and the production of soft-curd milk. The tests used for the detection of udder infection were bacteria and leucocyte count of the milk, the black cloth test for flakiness, and a physical emination of the udder for indurated tissue. 24. In all cases the milk from streptococcus infected quarters was lower in curd tension than that from normal quarters. The milk from staphylococcus arrested quarters had a high curd tension. here was no correlation between the mesence of indnrated tissue and soft-curd milk. m curd tension of the milk was lowered by infection sufficiently to warrant its classification as soft-curd milk. 25. DISCUSSION AND SUMMARY OF THE REVIEW OF LITERATURE Gastric digestion. A review of the literature shows that diges- tion takes place in the stomach by chemical solution. ll‘he solvents are hydrochloric acid and pepsin. These chemicals are present at birth and are secreted by the glands of the mucosa throughout the life of the individual. Ehe pH of the pure digestive Juice is 2.7. The pH of the stomach contents in the infant increased after the ingestion of milk. This is due to the buffer capacity of the milk. The buffer ability of milk is due to the casein and mineral content. Host investigators found that the pl! of the gastric con- tents was 5.75 to 4.6. llost workers agreed that the greater concentration of buffer constituents in cows' milk over human breast milk may cause diges- tive disorders. However, this idea has not been definitely substan- tiated. leading pediatricians have advocated that these disorders can be eliminated by the feeding of acidified cows' milk if arti- ficial feeding of the infants must be practiced. Hydrochloric acid coagulation and precipitation is used inter- changeably by Wang and Wood (50). That these two processes are hmdamentally different chemical processes is indicated since: (a) In rennin action on the casein there is produced a substance knom as paracasein and by the action of the soluble calcium this substance is coegulated yielding a mass which apparently contains all of the ingredients of the milk. The solid coagulumis calcium paracasein- ate. Il'he pH of the milk remains unchanged. (b) With Wochloric acid action on the milk the p11 of the milk is imediately reduced to .r n u .r. - I .._.I. :..E ' -'--..(" 1" I : .1- r . . .J .. '.: ' -"-: _' l l‘!" .'- L' ‘5'. "... . .'. : n: . . '-' : .. -- - . .- . .. . - ' ." " "n- . . - -r' - ' . r . . _ . ' .. -- .-- I .._ .. L . . . -' '—l_|. a _. - 12 '1 .3 . - -.- -.- ' . . . -- . Ir. . - a .' . - .- . .-)_ 1' .' '- ..--.£'..-'_'.r -: . 1 ;: r- :2 r_.| .'. 1"» no! :." :-::- M: 9-: ' ":‘r :t-m z jun-e. .ri:"'1.w‘.d . . '. .2 z:' - .:.-.' ' .'.- 2.”; 'i' . ' ' " ...‘ILn ._-:...- tr -. _' .. .' : .. ;:_.c- . . r.‘ ._ .., :.:’-' afar-.‘." -:-.: :- .=-. .3 -_r ' :2 . . .'.-r .3 .2 III. - 1.- I . ' I'- ---:--| ' ..‘n-I! . . y . .- . _ an“? - . .. - n - . . - _. -. u. ..- I' -._'. E's.» . _ w - . - I“ . .' . I . I. I --r ' II I l l ' - ' .. um. .: - a . '. ' ' . _: .- ' _ : . .- . . - - - . .- _' . ' - . _ .... ' ... I 'I In- . .' a L‘ f; '..-. ' . -' l ... ' .- y'.'- .- . .-. 5'. - I .- - '..I . .J J. . _- .i' "I .- .- w .. .-... II- - ._.- ,. . I.- l - ._. - : J-. I... ,_ . - u -- n .I.. I. 1. ... . r... a- - - _ ...-s r .. . _;. u'- 1.. - n ' '.r.q-- r - .. . .. . ....A 26. a point near the isoelectric point of casein. This isoelectric point is 4.6. At a pH of 5.5 the casein starts to separate frum the whey ad the whey soluble substances. Acid precipitation yields a nearly chemically pure casein and this differs greatLv from the calcium paracaseinate clot found by rennin‘action. This last process is the one which probably tabs place in the digestive tract. here is cmsdderable controversy over the apparent advantages offered by soft-curd milk as, infant food. No work has been reported which warrants the drawing of definite occlusions. However, if actual acid precipitation of the casein takes place in the stomach then it is very difficult to conceive of any advantage of milk which on rennin coagulation has a soft-curd diaracter. Soft-curd milk. The first qumtitative test for curd tension of milk was reported by Hill in 1916. Since that time numerous modifica- tions have been tried but their principles have not deviated far from the original method. llany chemical constituents of milk seemed to affect curd character. If these are added separately in excessive amounts to milk greater varia- tion: from normal curd tension is obtained. However, as yet only the cas- ein in normal milk has been found to have any influence on curd tension. It is generally agreed that the physical factors which influence curd character are the time of coagulation, the temperature of the milk and the amount of agitation. 27. Recently many processes have been reported whereby artificial soft-curd milk can be produced. Such as the application of heat and homogenization and the base-exchange process. In the past few years many workers have expressed opinion that udder infections are the underlying conditions causing the produc- tion of soft-curd milk. Few facts are available as yet. It is apparent that more vork is necessary to determine the relationship of mastitis to the curd character of milk. ... . 0 .- . ._ . .. . . _ H .r ... u . .I— \u . nu . I . ..L . . . .- . _.- ..u . ... . u .. l I . . u. . u . ... . - . a _ .. . _ . _ . _ t .. . . .. _ _ . . _ . a . . _ . . . . h r . . .. _ . — L . l .J I . . u . - OBJECT ihe object of this investigation is to determine the re- lation of a mastitis infection of the my gland to the curd character of the milk. in attempt will be made to correlate the following points with curd character. (a) (b) (o) (d) (a) (f) (e) The leucooyte count of the milk. rho pH of the milk as designated by the bran thymol blue test. The presence of streptococcus infection of the unwary gland. the per cent of chlorides in the milk. The presence of indurated udder tissue. The physical properties of the milk. The butterfat test. Selection of Animals. 29. Twentybtwo producing cows of various breeds will be selected from the college herd. of an active infection of mastitis. to be free of mastitis. One-half of these cows will have a history The remainder of the group are The following individuals will be used in this investigation. Kernel Group Cow Infected Group 00' 4 28 66 8? Breed Guernsey Guernsey Guernsey Jersey Jersey Jersey Ayrshire Holstein Holstein Holstein Brown Swiss Breed Guernsey Guernsey Guernsey Jerseyb Jersey No No No no No No No No No No History of mastitis record record record record record record record record record record record of mastitis of mastitis of mastitis of mastitis of mastitis of mastitis of mastitis of mastitis of mastitis of mastitis of mastitis History of mastitis infection infection infection infection infection infection infection infection infection infection infection This animal showed the first infection of mastitis during February 1933. is chronic sub-clinical case. This This animal showed positive to strept culture in may, 1933. This is classed as a chronic sub-clinical case. This animal has shown chronic sub-clin- ical mastitis since June, 1933. The presence of streptococci was first detected in September. 1933. a chronic sub-clinical case. This is This animal had an acute attack of clin- ical mastitis in september, 1933. Since that time has shown advanced stages of the disease. . r — . _ . . . . . _ . . . . . '_ .- . . . ._ _ . . _ _I g _ .._ u I . ‘. ,, - . . . . - , . . _. . .- I ' . ' . .- .' .. J . - . . _ ._ ._ _ . -, ‘ ' ' ' . - ...-' . _l .I l . ... .. . ... . . . - , _., . . . ... .- . ... . ._ . --; - . . . . . ._. . . , I _ . I.- ‘ I 1-. I - g . .- . . .. . - - u. - . ' ' - f .. " - .. u . .l. -.. n ‘. | . . 'l '. .'.. . - r ....- l . .\- 50. Infected Group (Cont '11) Get Breed History of metitis 71 Jersey This animal has had a chronic sub- clinical case of mstitis since Jan- nary, 1933. 132 Ayrshire This animal had shown no positive pres- ence of streptococci by the cultural Nth“. 172 Holstein This animal has shown a chronic clinical infection intermittently since January, 1933. 171 Holstein This mimal has shown a chronic clinical infection intermittently since January, 1933. 167 Bolstein This animal has shown a chronic clinical infection intermittently since January, 1933. 242 Brown Swiss This animal has shewn a chronic clinical infection at intermittent periods since January, 1933. Securing of Samples Each month one-half pint samples will be obtained from each of the four quarters from each cow selected for this project. Curd Tension Test The Hill test as described on page 10 will be used in making all curd tension determinations. Detection of mastitis The following test for the detection of mastitis infection of the udder will be used. (a) The direct microscopic method of determining leucocytes per c.c. of milk. (b) The pH of the mill: by the brom thymol blue test, as follows, four drops of concentrated solution of brom thymOl blue is added to 3 c.c. of the milk. The color produced is com- pared to the chart. (c) The per cent chloride is detemined by dilut- 31. ing ten c.c. of milk with 40 c.c. of distilled water. To this solution add ten c.c. of potassium chromate and titrate with 11/10 silver nitrate. The chlorides are calculated as one c.c. of silver nitrate equaling 0.355 ug. of chlorides. (d) The butter- fat test will be determined by the "Babcock Test". (9) The pres- ence of streptococci will be determined by the following cultural procedure. One-tenth c.c. of thoroughly mixed milk is placed in a sterile petri dish yielding a one to ten dilution. To each petri dish is added, asceptically, eight to ten c.c. of gentian-violet liver infusion blood agar and rotated to thoroughly mixed the agar and the milk. The plates are incubated for 36 hours at 37° 0. (f) The physical examination of the udder will be carried out as follows. Weigh the two front quarters simultaneously by using one hand for each quarter. Repeat this procedure on the rear quarters. Carefully carry out deep palpation of each quarter for detecting presence of indurated udder tissue. (g) The physical examination of the milk will be done by the use of‘the strip cup to detect flakinese and garget in the milk. in examination of the milk will be made to detect any changes in appearance. 52 . PROCEDURE Securing of Samples The samples were secured as originally planned. Hethod of Pre-Heating Prior to Testing 'mie milk was left in the sample jars and these were placed in a suitable container. The container was then placed matter a stream of running hot water. This permitted the rapid raising of the tem- perature to 35°C which was the temperature mintained throughout the test. The Coagulant The coagulant consists of a solution of 0.6 per cent one-3000 dry scale pepsin and a solution of 37.8 per cent dry granular cal- cium chloride. These two solutions were added to the milk separate1y. The Coagulating Cylinders. Standard 250 c.c. low type pyrex beakers were used. The Water Bath An electrically heated water bath was used. The water contained in this bath was kept at a temperature of 38°C. It was determined e:- perimentally that the temperature of the water must be at least three degrees higier than the temperature which is desirable to maintain within the milk. The knife was placed in the water bath when it was not in actual use. The Testing Procedure Seven and one-half c.c. of the pepsin solution was placed into each of eight clean coagulating cyliniers. . I , u . _. .. . ... . I I l _ . . a. .. .._.. - . . . . .. . I l I. I ‘II I . . ~ .. I. I L . . . . -.. I II — " I. ' I. . - .. — . I a - . . _. —. . _ . I. - ' I . _ _ . - . I . '- . - ' ' l - 3" I. Q ' .. .- - . r , . *J. .- to O ... . I- ‘. ' ..l ...-. .' I . . . l . .I J . - I '. .l I .. . . , f l _ .. . . - . . . . . . __ .. . . .. . - l . . . .." . .IIL-I. ' _ =1 -. ... . __ — l .o r O , .... ..-. .. . . . __ . . ' - 'r. . . . Us. .... ..-. '.- n J. I' ‘ - . " . '. . - .'-... 53. The milk as preheated was thoroughly mixed and a 100 c.c. portion measured into a graduate. To this was added two and one- half. c.c. or calcim chloride solution. The graduate was inediate- 1y revolved so as to insure complete mixing of the two substances. Into one or the beakers containing the pepsin solution was placed one or the curd knives. The beaker was then immersed in the water-bath and the milk poured into it at a rapid but smooth rate. 'This method was found to be most acceptable. from the stampoint of thoroughly mixing the milk with the coagulate. This procedure was repeated at one minute intervals with duplicate samples from em of the four quarters of an individual cow. A period or ten minutes was allowed for coagulation. The beaker of coagulated milk was removed from the water bath at the temination of the coagulation period. The metal plug was carefully ejected from the shaft or the knife. The platform was raised to the necessary level and the beaker of curded milk placed upon it. By careful manipulation the heck of the scale was attached to the loop of the knife and the platform released. is the force required to start the knife through the curd is large compared to the normal cutting force this figure is not used in experimental data. After this initial break there will be a quick adjustment ot'the scale to the actual force required to out the curd which was designated by the leveling of: of the dial to a constant figure. This reading was obtained and used in making experimental observations. xsléuoq 1:! :0 .3.0 1:21.: on LI. "."I'rv..-'1 \;_[ J1!“ can}. r. 015- :'_-. 03.21 Let-3'02 L130: .u' 0:: 'JI‘C'; 0:3? '1") ivy-411.21 i.; - ' .. :z ' .I'.: u -.. 'L :I(.:-.- ". ."""..'_ _."..I.'.1 l." 1-- : .:'.; .1053: e..'..'.‘. ‘..J. !.";--'=:."5..-... L:-:.' 'r.‘ :'-‘ .'.I. 1...: J _I.'- J5... 0:." r..' "a. ':' u.’ If -I)'.' c‘ 5: Est; 3.“.- J':...':. 0 L" .'\-¢.' 2'. .'2' .'.- _'";.': -:.'.. -..;- ails." .,-:".n" '.-._'....'.:‘ INN-3.. 1.2 -':' :-- u- ' '_ -... ' A _I___'-.« £3 _ : .'. 'z'.‘ :' £.-'.'..'5..--._’ tin: um?" . . ' .L .1" ' ’3? I .'.}. .' ,. :1- ' -.:- .' I: ::.-'. :.:.'. ud' I...-. .'t. .5 ':5 . -_|- J. ,. :.'.- 5y;- 1.3." __ 3:1; ' "1:: j ”I b. 5 ';_:' 12...:5- .‘ 1.. ' x.‘ .- :-'-'f' ' 'r .-"*.:-:-- :5: .):.=.-.'.-' "'0 new ' ":.'t. . 2. .I' .'I "Mitt-1' .\ .. 1.17. -.' \_'- .'- .. .. .1 EXPERIMENTAL DATA The (find. Test rho curd test consists of a hydraulic elevating platform. The speed of the downward movement of the platform is regulated by a screw valve in the continuous oil line. A byhpass valve in the pump cylinder allows for rapid raising of the platform. The platform is approximately one and one-half pounds in weight. This is sufficient weight to insure smooth and uniform motion of the platform as it proceeds downward. The gram scale is of the dial spring type. It is accurate to one-half grAm and sensitive to one-fourth gram. mhe calibrations are in two grams units and runs from a minus 30 to a positive 200 grams. The calibrations below zero are for the allowance of the weight of the knife. The scale is adjustable to both zero and span readings. These units of platform and scale are combined into one com- pact unit by the use of a steel frame which is suitable for ringu stand mounting. The knife has a shaft four inches in length and is uniform in diameter throughout its entire length. These are cut from three- sixteenths inch hollow brass tubing. There are four radiating blades which are encircled by a rim of like material. These baldes are cut from one-twentieth inch sheet brass and are three-eighths of an inch wide. Both edges of these blades are made extremely sharp and are made concave so as to set firmly on the bottom of the beaker. The upper edge is presented to the coagulated milk and used as the cut- ting surface. The bottom edge of the blades are sharpened so as to a u.- . . n a . .- _ u - . . - '. .' . . . ' .___ E '-. . .:": -' OI -- .. - ' ' .I- . . ' r 1 j .-_._i . - ‘ . .... .." . i. 1? - ."'-r- .-. - n: . .' .- . I u .- . ' . . _. .. .i - .. .. .' . . .n . ' . I .'_'_ .' I- -. .' .' : .. . .l, . .r f: . 1, . .- .. - . .III . ' . s ' '. .'. J' -. '5" ‘I I..'. I \ '. u' ' _, II. — ll' - . f l _ ... n l - Ins . .-.. . . I - . r- . . . -..- '- . 55. sponsor immediate closing of its path after it has cut the curd and proceeds upwards. A metal p113 is inserted into the hollow shaft while coagulation of the milk is taking place. This is removed at the tins of making the curd character reading. The Effect of llastitis on the Curd character of Milk Ieucocytes per c.c. and I” sent chlorides. The following tables give an average of the leucocytes per c.c. and the per out chlorides for the entire period. fable X - 'me effect of leucocytes per c.c. and per cent chlorides on curd character. Normal group of cows Third character: feucocytes : Elorides: 3 No in grams 3 pg: cent 3 per cent : streptu Quarters 0-50 78.815 0.171 - 27 51-50 127.554 0.159 - 90 above 50 127.218 0.152 - 55 Table II - The effect of leueocytes per c.c. and the per cent chlorides on curd character» Infected group Ford character: ’feucocytes .mm... 3 no in grams 3193' c.c. 3732’ cent : strept.: More 0-50 1,025,500 0.165 - 10 31-50 949 , 351 0.151 - 41 above 50 279,494 0.154 - 17 0-50 12,078,000 0.219 x 52 51-50 3,568,000 0.195 x 25 above 50 8,155,000 0.197 x 3 * Cow number 66 was excluded from this smary an. influence of the intermittent Lresonco of the streptococci organism. Table XII is a emery of those cows from the infected group which some months showed streptococci organism and other months showed an absence of this organism in the same quarter. ...... . . . . . . .. . - . _ \ . - _ .-I - I. .- O .. m . ... ..e- .. . ... -. -. - .4 . \ I I. k . . . . . . . . .r | _ - .. . l . - l . . .- \ . .‘ . __.- . a . ' l . u- .- - l . . J .. ._ . . w .. .. . -. _ '- ...... .. a. '- .' . a . l . . ... .. ' :r' '3 .. ,' “(.'II'; ':- 1.1 '. l ':" Table III : :mofides: retard charact or? lonth :Quarter: _per cent:St1'9fi. : _jgrams Cow 28 November 3.13. 0.16 x 40-41 February 3.3. 0.12 - 68-64 larch 11.3. 0.17 x 52-32 April R.R. 0.18 - 33-35 NO'amber Re? e O. 15 x 47-47 February RJ'. 0.11 - 58-58 March 3.1. 0.16 x 28-29 ”:11 3.3. 0016 - 32-32 November LP. 0.16 x 43-43 February Le? e 0 e 11 " 60-58 March LP. 0.16 x 28-28 April LP. 0.18 - 29-27 November L.R e 0 e 1 6 "' 62.54 Febmy Inn e 00 12 - 61 llaroh LR. 0.14 x 33-30 April LR. 0.19 - 32-32 Cow 132 December RJ‘. 0.14 - 70 February RJ‘. 0.14 - 50 mch R eF e 0 e 12 x 32 larch RJ‘. 0.16 - 41-41 April RJ'. 0.16 x 17-16 Havenber II .F e 0e 33 I 15-13 March Inf. 0.17 - 42-43 ”r11 IleF e 0e 23 I 12-13 Co! 171 February R.F. 0.10 - 22-24 larch RJ'. 0.17 x 20-19 m1]. R.F. Del? 2 11'10 Fabmry II or e 0 e 10 " 24.25 “Ch In? e 0 e 14 - 21-21 April 15.3. 0.15 x 17-17 Cow 4 February RJ‘. 0.17 - 55-55 “Oh R .R. 0021 " 36 April 3.11. 0.29 x 29-31 December RJ'. 0.14 - 70-70 February R.F. 0.14 - 51-58 R .F O 0.12 I 32.31 nrch 56. . . . ... _ . . _. . . rm . . a. c . . . . . ._ ... .- .__'_. ' .L. ..J.e ' . . .. . D O I U Q .0 0 I ‘ 0.0I 0 "LL: ._ E . l .- _ 0 I O O I . C Q Q 0 I 0 ..n _ . ... . . . r. . I . 37. Cow No. 66, showed a great deviation from normal as compared to the other animals. The fimiings are sunmarized in the following table. Table XIII : : z :moridés: Fat :53 m Month :Quarter: 3.53.3. :Strept.;per cent: 75 : grams CO! 66 November R.R. Normal R 0F 0 Normal LQF. Nbrmal I..R. Normal 0.16 3.2 26 0.16 3.3 39 0.16 3.2 48 0.16 3.6 60-59 lilN 0.21 4.9 62-62 0.17 3.7 70-70 0.17 3.7 74-47 0.17 3.9 100-91 December 3.3. V.L.G. R.F. Normal LeFe NOW]. Len e Normal IIIH 0.24 4.9 105-96 0019 5.1 91799 0.22 5.5 103 0.18 5.6 55-57 February R.R. Vs L.G. 39F e Normal LeF 0 Normal L.R. Normal IIIH mch ReRe VeLeGe x 0.22 5.6 80-77 ReFe VeLeGe " 0.20 5e0 '- IieFe YoLoGo x 0.23 4.8 67‘65 13.3. veLeGe x Doze 5e]. 52-53 m1]. ROB. DoGo I 0.31 5.2 65-62 ROFO Notmal x 0.29 5.5 "“ LOFO Rom]. "' 0.25 409 _- LORO mom]. I 0022 5.4 64—61 The effect of an high acid content of milk. The data showing the effect of a h1g1 acid cmtent of milk taken from one individual cow be- cause of the apparent abnormal results obtained during the month in which the milk showed'an increased acidity by the bran thymol blue test. --I. .. .. ' .. ~ ' . . . ...,v 'I. - .l. . - .- .. r . . I“. . I - . ) .. ..i . ‘ . . .5' " ' -' ...-:11 l' .. . ' '. MO I.-.-. .. marl- .3. ..:l- ...-I— - _-: 5 . . .: i: . -: - . . . .z.._....-. . . ... . - . - - -.-......—...-. . i”. .t.‘ . . 5? I1. -.' '- . ... ' -O ‘I Q g .. "'J:-:DI' l .I 'I 'l ‘ ' ' ‘." . Is " '- '1 m e. u '1 r- '_ - 'o t. - "' - " .- l' O . ; "' I .'. "e . " —'- '-'-'-' w w:. I u , I .. . ..- \ '."'. _ u ' .. o q. 'n. .'. .__ ‘ . - . - .7. _.e " s s ,. . . __ -.. "' e'e . V" - ' s- v . .- . .._ . ,-. . . -"u- a —.'w 0'. o:e - .. . . ' .._.. -. f.‘ .. .'. --~- w e ......— _... .-.U -. (_- -_[.- . ..- .. - I. 'e - Ie- -' J: ""' " w e. .._--.. . ... .. -_ . .......-....-.-........ .--.......-.. '4‘ .'I ' ',- ' \ {I W 0 I.“ . ‘ C. . - "'1': .I".:::--- :. 5.' n. 1 l: .1 '. ' . ...-....----... ..-.... .. .-_..._.. .. . . . . . . ~ . 'v' : . . 'o.":(.vn- ._. .:‘-:‘- -.' \ . . 1'_n ". .r ' ' '. ' '.- “..' .'. .'2 11-" i 1' '-'. - '(J "' g; .. . .. II . '.~ ‘ \ -_- 'C'. I. ' ~ '31.“: ' . I... . L .-'.'. Table m - The effect of a high acid December February larch content : z 3 3 Ford North : Quarter : B.T.B. : Strep}. : character R.R. Iellow‘ - 68-61 R.F. Yellow - 70-70 D.F. Yellow - 70-69 3.3. Yellow - 70-71 has. Normal - 45-49 R.F. Nod-ml - 51-48 I..F. Normal - 45-44 13.1.1. Normal - 50 11.3. Norml - 40-55 R.F. Normal x 32-31 I..F. Normal - 37-35 LeRe NW1 '- 37 " The yellow color is on the acid side of the range of color change with the indicator brom thymol blue. The effect of fat on the curd character. The data taken from the normal group of cows showing the effect of fat on card character are presented in Table IV. Table X7 - The effect of fat on the curd character ‘55s: cent ‘ifiurd character : Nuiber of fat 3 :_grams 3 cases 0 - 3.5 33.3 38 5.5 ‘ 5.0 45.8 79 Above 500 5401 55 39. DISCUSSION OF EXPERIMENTAL DATA In a preliminary experiment the two instruments recomended by the man Agricultural Experimental Station were used. However, these instruments failed to give satisfactory checks for curd character on duplicate samples of milk. An instrument was developed which gave satisfactory results. The Card Test It was found that the greatest error introduced by the instru- ments in semen use for curd character determinations was that caused by the human element controlling the speed at which the knife was drawn throng: the coagulated milk. This was eliminated by the hydrau- lic pulsp principle employed on the Curd Test. The downward speed of the platform which is attached to the free and of the pump shaft should require from 18 to 25 seconds to travel through a distance of five centimters. This motion is made uniform and smooth by the use of a heavy iron platform. The weight of the platform plus the milk and coagulating cylinder is approximately two pounds. The dial type spring balance was used because of its ability to adJust itself rapidly to the actual cutting force after the abnormal initial break. This rapidity is acquired because it is necessary for the spring to make only one-half revolution in order for the hand to register a force of 200 grams. The distance ahich the knife travels during this adjustment is from one to two centimeters. In the use of the conventional coiled spring balance this adjustment is not attained as the space through which the knife must travel during this adjustment is so great that the mife is out of the curd before the adjustment is complete. ‘merefore. only the abnormally large force required to start the knife cutting is registered. i change of temperature seems to throw the scale slightly out of adjustment. This factor was eliminated by providing means of adjustment for both ears and span readings. The curd knife as part of the curd test differs considerably from those of other instrumnts. In Previous work with gelatin and agar solidified solutions it was found that the large center shaft of the Hill knife apparently allowed the formtion of a vacuum which greatly affected results. Also the speed which is desirable in drawing the lmife through the curd was too slow for the knife to cut cleanly. This is due to the small angles formed by the blades at the center of the knife. The first factor was eliminated by mak- ing the shaft from hollow brass tubing and inserting a raucvable metal plug. A clean out was obtained by manufacturing a knife which did not present angles less than 90°. It was then found that regardless of the speed used, clean cutting of the coagulated milk is always attained. This is true regardless of the hardness of the curd. In test trials with this instrument with ten or more samples of milk with a curd character of 45 grams or less the variation did not exceed three yams. Such exact che cks are not always attained but whether this is because of faulty mechanism or improper technique and care is questionable. Hill: which runs from 60 to 100 grams curd character will check within seven per cent of variation. Hill claims it checks within five grams on soft-curd milk with his apparatus. Hill: with a curd character from zero to 50 grams was classified as soft- ourd milk. This allowed for about 17 per cent variation for this type 41. of milk as compared to only about a six per cent variation with the instrument used in this investigation. The efficient Operation of this instrument requires very little practice. The Effect of nastitis on the Curd.Character of lilk Leucocytes‘pgr_c.c. and.the_per cent chlorides. In the cases studied it was shown in general that the leucccyte comt increased as the severity of the infection bucreased. adders hasing‘both.infected and non-infected quarters showed a higher leucocyte count in those in- fected by mastitis. There was, however, so wide a variation in this respect between individual animals and so marry other influences on the curd character of milk that a correlation between these points is impossible. The data indicates that the curd character of the milk is not affected until the leueocytes exceed 3,000,000 per c.c. un- doubtedly even this large count played little part in.altering the curd character of the milk but maybe a normal phenomenon in the de- fense by the organism in the presence of inflamatory processes. The data chow that the per cent of chlorides greatly influenced curd character of the milk from both infected and non-infected quarters. is shown in.Table XI, a tendency exists for the per cent chlorides to increase as the curd character reading decreases. The mean of 0.159 per cent seems to be in accord with more extensive work carried on at this station. The chloride content of the milk from quarters showing negative to streptococcus cultures was not significantly different from that of the milk from the normal group of cows. Milk from the quarters that were positive to streptococcus tests had.a considercbly higher chloride content than milk from the non-infected quarters. There was also a tendency for the chlorides to increase as the curd . I I . _ I . I I .-_ . I. a I ._ I . . . . . .- .. I .I-I.. III I . l. \— - . . . 'i - '. ~ ' .. '. -'— . . .. I . .. . I . . . . . . . .. . _ l. . . . . - '- . I ' U ' .I .l ' . I 7 I I e--. - . - __ I I - - . . I I - - -.. . .: ' . 1' ' . - ...-...-....-.. ... .. .. .-.. .... ...... .I.. . . ‘ .. I . . ... ... .. . .. .._...-- .I . . . ' . II . . , . ‘ . . I. ' . .- I I ' .. 4 .- . a - . ... .. '. 1L .' I a. .' . ' t 3 . . _ : . _ . . . - ' e -' ' ' . '.- ' ' :. .’. ...-' -_ - .. ,- - . l.‘ - _ - . ' ..._'_ '_ I' - ' .- .' I... I- II o- .- . - . - . .-.-.- . .I I . '.— I. I . I . . I .. . . ‘ I. :. . p' - _| l f . ..';9' . . . . - . , . . . .- . . .. ..- I I . '. . . I I. . - . . . . w- .. . .--- . - _ . . . . . _ . .' .I I I .. . I . .' I "I' I "- si-e' ' ' s a H '- '.- .. . ' ' ' "-"- I I . I .I . I_ I - . . . . 4 . '- '1 . ' .. . - .' ---.:".."' .- I -II . I I . I . . _- ,II I I I-I -I I ‘ - . 'I. -. . '.I. . I ._ . ' ' . I . '- ' . ‘ - . . - e -_.. . .. ' 'l. I '. . I-'. I . II'_I I I ' I' - - ."' I ' . ' I . . I.- I I. a . I -. I ' - I " ' '. . - ' .'-' I I- . .. - ‘ .. . - , I - I . . ' . . . . I. .. . I . I . ' l .. . w . . - . i - -. - - .- . .. - ' -'- - . I 'I- I . ‘ . ' . . -I . . -. . ... . w.- . I . .'. I- I I .I . I I .' I I III -. II I . II I I' . ' ' . ‘ I. l' ' . - ' . - . I. ' . "'l I. II‘ . II I' I'I I . I I .II- . I .... . . - '_. . I..- 'I .-- I' I. :- I . . - I I ' I I I I ' I ‘ .l I l I 42. character reading decreases. There was a significant difference be- tween the mean per cent chlorides of thousand group and that for the cows positive to streptococcus. The difference of the means is 0.049 and the standard error for the positive group is. 0.012. To be significant 0.049 must exceed 0.012, two or more times. This re- quirement is greatly exceeded. In work carried on at the Pennsylvania station (52) there was no relation between chlorides aha curd character. The data furnished by this investigation showed a higher per cent of chlorides for both normal and abnormal milk than was found by these workers. The tech- nique employed was identical and the variation is difficult to account for. The effect of an intermittent presence and absence of the strepto- coccus organism. There were ll quarters which showed streptococcus organism in the milk one month and the next month were negative to the culture test. In all of the cases the curd character reading was lower for that period during which the infection was active as shown by the presence of the organism. The leucocytes did not necessarily increase during the active infection but in general showed greater numbers. The per cent chlorides increased as the curd character decreased in nearly every case. Cow number 66 in the infected group reacted very abnormally during the entire investigation. In December, 1933, the per cent chlorides increased over the preceding month. During the some period the curd character reading increased about 100 per cent. In February the same trend was shown. However, in March, 1934, there was again an increase in the chlorides but the curd character reading began to fall. The 43 . final month showed a great increase in the chlorides and a consider- able decrease in the curd character. The milk from this individual presented a very rubbery mass on coagulation and it was very difficult to obtain a true curd reading. These results are very difficult to explain and no attempt will be made to account for them. The effect of abnormal acidity of milk on the curd character. It was shown by weisberg and coworkers (53) that the curd character of milk can be increased by the addition of an acid md decreased by the addition of an alkali. Evidence from the work at the Pennsylvania Station (52) indicates that an increase in the pH of milk caused by mastitis infectiOn lowers the curd character reading. Results from one cow used in this investigation were in accord with this evidence. During the month of December, 1953, the milk from this cow showed a distinct yellow color upon the addition of brom thymol blue indica- tor. The curd character reading during this month averaged 68 grams for the four quarters. By February the reaction of the milk to the indicator had returned to norml and the curd character reading had dropped to an average of 48 grams. The following month the color was normal and the curd character was 58 grams, for the milk frm the four quarters. It is reasonable to assume that during the month of December the pH of the milk was reduced to about 6.0 to 6.2 and. it is in this range that the enzymic activity is the greatest. This might have been the cause of the harder curd at the lower pH reading, but the data are entirely too meager to be conclusive. 44. The influence of the fat content of the milk on curd character. Bill (30) concluded that soft-curd milk is usually produced by the lower testing breeds but some high testing cows will give a soft-curd milk. Using the various breeds in compiling the data given in Table IV it is shown that as the fat content of the milk increases the curd character increases. This is in accord with the results of other workers. SUMMARY 1. An apparatus was developed for determining curd character. This instrument proved to be accurate for curd character determinations. 2. Twenty-two cows from the College herd, which were equally divided into an infected and a non-infected group, were used in studying the influence of mastitis on the character of the curd. 3. The leucocyte count played little, if any, part in determining the and character. 4. The chloride content of the milk increased as the curd character reading decreased. This was true with both normal and abnormal milk. 1. 2. 3. 4. 5a 5. 7. 8. 9. 10. 11. 12. 13. 46. LEW CITED Soft-Curd llilk is Easier to Digest 1934 'me Ayrshire Digest, Vol. 20, page 9. Ayrshires head as Soft-Curd Milk Producers 1934. 'Ehe Ayrshire Digest, Vol. 20. D889 12. Alleman, D. and H. Schmidt 1916 Ueber die Festigknit des durch Laberzaugten milchhoagulums Landu. Jahrb. Schwiz, Vol. 30, page 355. “801', B. 1932 Soft-Curd llilk Offers a New Market The Jersey Bulletin, Vol. 51, page 333 Bomrth, A. '0 1921 The Main of Cows' m1): and Its Relation to the Digestion and Absorption of Casein. Protein Curds in Stools. American Journal of Diseases of Children, Vol. 22, page 613. Bosworth, A. W. 1921 Studies in Infant Feeding. Anerimn Journal of Diseases of Children, Vol. 22. P869 455. Dosworth, A. I. 1921 Studios in Infant Feeding. American Journal of Diseases of Children, Vol. 22, page 193. Brennemann, J. 1929 The Curd and the Buffer in Infant Feeding. Journal Anerican Hedical Association, Vol. 92, page 364. Drennemann, J. 1917 no Coagulation of llilk in the Human Stomach. Archives of Pediatrics, Vol. 34, page 81. mm. B. P. 1928 The Digestive Work of the Stomach Physiological Reviews, Vol. 8, page 365. Babbctt, Jr., F. I... J. A. Johnston, C. H. Haskins and A. T. Shohl 1923 Hydrogen-ion Concentration of Gastric Contents of Infants. American Journal of Diseases of Children. Vol. 26, page 475 Bolton, C. and G. I. Goodhart. 1931 Variation in Acidity of Gastric Juice During Secretion. Journal of Plursiology , Vol. 73, 115 Carlson, A. J. 1923 The Secretion of Gastric Juice During Health and Disease. Physiological Reviews, vol. 3, page 1. r“ .u .u I .. .. r. .. .1. . u . +u . .. . . . _ .. ... u . . Q . . .. . . . I“ . a. .| u u . ... . s . l . .. . o .. . a .. . .u: ... ._ . . . . w . . - . s. a . . . u. . O u . .0 . n. u . . . . ... _ _ . n . .. . . 1 . — L \I .- ... ... . . . . I.. .. . I. . C . Q ..u .I. Q n .\u . a. . I . . a . ..n .u .. r . .. a .. o a . .. w .. . .— t .. C a. ... . o. . . o . s . a . . . . . I .. L. .. . . ... In - .. . T In. . . ...... .. .[ 14. 15. 16. 17. 18. 19. 20. 23. 26. 46. Cassie, G. and U. Cox 1926 Examination of Gastric Contents of Infants Journal American Medical Association, Vol. 87, page 1244. Courtney, A. M. 1927 Difference in Behavior of Raw, Pasteurised, Boiled, Evaporated and Dried Milk at Hydrogen-ion Concentration of Stomach. The Canadian Medical Association Journal, Vol. 17, page 919. Corbin, Dr. Ca Is 1933 Soft-Curd Milk, Part 1. Certified Milk, Vol. 81, page 5. Corbin, Dr. C. I. 1933 soft-Curd Milk, Part 2. Certified Milk, V01. 82, page 5. Canon, C. 1‘. Personal Communication - Dairy Department Iowa State College ESPB. Do In and Jo ‘0 me 1932 Effect of Curd Tension en 111s Digestibility of Milk American Jaurnal of Diseases of Children, Vol. 43, page 62. Eli‘s. H. S. 1933 Soft-Curd Milk American Journal of Diseases of Children, Vol. 44, page 296 P‘ber' K. K. ”11 F. Baden 1922 The Difference in the Hydrogen-ion Concentration and the Buffer Value of Foods on Digestion Medical Clinic of North Amrica, Vol. 6, page 245. Faber, H. K. 1923 Hydrochloric Acid Milk in Infant Feeding. American Journal of Diseases of Children, Vol. 26, page 401. Congo, J. E. and M. L. Templeton 1930 Gastric Digestion in Nev-Born Infants. American Journal of Diseases of Children, Vol. 26, page 542. Griswold, Ce m A. To $1011]. 1923 Gastric Digestion in Mew-Born Infants American Journal of Diseases of Children, Vol. 26, page 542. Hess, Mine 1!. 1922 Practices and Principles of Infant Feeding, Part 3, Chap. 3. F. A. Davis Company, Philadelphia. Hess, Mine 1!. 1922 Practices aid Principles of Infant Feeding, Part 1, Chap. 5. F. A. Davis Company, Philadelphia. . - . r _. .. - l ..'- . .. .f’ . . €- .. 2?. 28. 29. 30. 51. 32. 33. 34. 35. 36. 37. 38. 39. 47. Ross, Julius 11., Elisabeth M. Koch, Zella C. Sennewald 1926 Peptic Digestion of Cass Milk, the Effect of Various Modifications Used in Infant Feeding. ‘ Journal Anerican Medical Association, Vol. 87. P680 1360 3111. R. L. , 1928 The Physical Curd Character of Milk and Its Relationship to the Digestibility and Food Value for Infants. Utah Agricultural mpsrimait Station, Bulletin 207. Kill, R. 1.. 1927 Physical Curd Character of Milk and Its Probable Relation to Infant nutrition. Utah Agricultural Experiment Station, Bulletin 66. 3111. H. II. 1931 soft-Curd Milk. Utah Agricultural Experiment Station, Bulletin 227. 3111, Re L. 1933 A Decade and a Half of soft-Curd Milk Studies. Utah Agricultural Experimait Station. Circular Bulletin 191. Kill. R. L. 1931 soft-Curd Milk, Matures Food for Infants. Archives of Pediatrics, Vol. 48. P389 417. Holm, George E. and Byron n. lebb 1930 Buffer Capacity of Various Milks and Proprietary Infant Foods. American Journal of Disease of Children, Vol. 40, page 260. Hansen, R. (3., D. R. 'Bheophilus, F. W. Atkison and E. M. Geildon 1934 Influence of Mastitis on Curd Tension of Milk. Journal of Dairy Science, Vol. 17, page 257. Kalk, no Md Be mm 1925 ‘Ihe pH of the stomach Contents Klinische Uochensohrift, Berlin, Vol. 1801. 9883 1806. Kim, Me So and ‘0 Co I” 1933 an the Mode of Action of Secretagogues (Liver Extracts) in Premoting Gastric secretions. American Journal of Physiology, Vol. 105, page 220. 1925 Contribut ions to the Physiology of the Gastric Secret ion. Quarterly Journal of Experimental Physiology, Vol. 15, page 55. W. J. F0. 3. no mm m H. 3. 6.1761218 1933 Adjustment of Salts in Milk by Base-Emma Indnstrial and Engineering Chemistry, Vol. 25, page 1297. mun, Frank C. and Jesse L. Bellman 1930 me Reaction of the Contents of the Castro-Intestinal Tract. Journal American Medical Association, Vol. 95, page 1722. F.‘ ... . ... ,.: O .I.. .. .’. . . 41. 46. 47 . 49. 50. 61. 48. Morse and Talbot 1920 Diseases of Nutrition and Infant Feeding, pages 10-43 MacMillan Company, New York MacLeod, J. R. 1920 Physiolog and Bio-Chemistry in Modern medicine, pages 714—721 The C. V. Mosby Company, St. Louis. McLean, Hugh and William Griffith 1928 The Automatic Regulation of Gastric Acidity. Journal of Physiology, Vol. 66, page 356. Havens, W. B. and D. D. Shaw 1933 The Effect of Dairy Manufactung Processes on the nutritive Value of Milk. The Apparent Digestibility of Fresh Whole Milk and of Powdered Milk. The Journal of Nutrition, Vol. 6. P989 139. Mch, James E. 1923 Studies on the control of the Acidity of the Gastric Juice. The American Journal of Physiology, Vol. 89, page 483. Havens, w. B. and D. D. Shaw 1923 Hydrogen-ion Concentration of the Stomach. American Journal of Diseases of Children, Vol. 26, page 483. Sheftel, J. M. 1931 Influence of Acid on Gastric Secretion Journal American Medical Association, Vol. 97, page 361. Sismsen, Walter J. 1931 The Influence of Excessive Milk Feeding on Gastric motility and Its Relation to Chronic Anorexia. American Journal of Diseases of Children, Vol. 41, page 291. Strickland, Franklin 1!. 1934 Holstein Friesian World, Vol. 31, page 15. Vuelaume, R. 1924 Contribution to the Study of the Acidity of Abnormal Milka Lait 14, pages 12-25 Abstract from Chemical Abstracts, Vol. 28, page 1785. Wang, Chi Che and Agnes Wood 1930 The Optimum Conditions for the Precipitation of casein from Human and From Cows' Milk. Anerican Jourml of Diseases of Children, Vol. 40, page 569 Wang, C. C. and L. E. Davis 1924 A Comparison of Metabolism of Some Mineral Constituents of Cows' Milk and of Breast Milk in the same Infant. Chloride Metabolism. American Journal of Diseases of Children, Vol. 27, page 787. - v. . .I.. m . .u‘ . . . . .. u. . .0 .- _ . n . n. I . I . .... . ‘ I . . ,_ ‘ O I\ .1. 52. 53. 54. 550 49. Ielch, R. C. and F. J. mm. 1933 Sort-Curd Milk and Mastitis. Milk Plant Monthly, Vol. 22, page 30. Isisberg, S. M. and A. H. Johnson and E. V. McCallum. 1933 Laboratory Studies on the Chemistry of Sort-Curd Milk. Journal of Dairy Science, Vol. 16, page 225. Wills, L. W. and D. Paterson. 1926 Gastric Acidity in Infants. Journal American Medical Association, Vol. 87. page 1613 Walla-Laurence, Zonja and F. C. Koch. 1930 The Relative Digestibility of Wmetmed, Evaporated Milk, Boiled Milk and. Raw Milk by Trypsin in Vitro. American Journal of Diseases of Children, Vol. 39. page 18. APPEDIX 50. m TO TABLES IV I TO xxxv Inclusive R.R. - right rear BJ‘. - right fore L.F. - left fore L.R. - left rear B.T.B. - brom thmol blue B.F. - butter fat N. - normal G. - green VLG - very light green LG - ligxt green DG - dark green Oran - orange I - indurated S - slightly indurated Cl - Chlorides .._..ai - . ._.: .. . ......rr. ... ... .. .JFflrn .. . _ u.“ Table XVI - Data for 001.93»I 51. : Wait”: x :ml. 8 :Curd : m Ruhr-mar c.c. 23.9.3.3 Cl. :Enn. :Exan. :BJ‘. :Char.‘ :Strept :ter .per 1,000 : 3 i :of Uddersof mu: 3 1% :Reading: 307350! 3.3. 100 I .14 I I 4.9 66-64 - 3.3. 70 H 015 N I 502 51-52 " IloF. 700 I .15 I I 5.2 54-54 - 11.3. 50 N .15 N N 4.3 54-54 - December 3.3. 30 N .16 N I 5.4 42 - R.F. 50 I .17 N H 4.8 44-44 - 11.3. 55 N .17 N I 4.9 50-51 - 5.3. 50 N .17 N N 5.5 45-47 - Febrmry 3.12. 20 I .11 I! N 4.3 65-70 - R.F. 40 H .18 N H 4.4 55-55 - DJ. 18 N .14 U-S N 4.5 50-52 '- Ld. 19 I .14 H-S I 4.7 59 ~ * Date of calving -»9/3/ss T5516 XVII - Data for CO' 170‘ 3076.136! 3.3. 53 I .17 N I 4.4 40-42 - RJ'. 40 N .15 N N 4.0 55-54 - LOP. 50 N .17 N N 4.0 33757 - 13.3. 20 N .17 N N 4.2 54-51 - DOM“! 3.3. 53 N .19 N N 5.5 25-34 - R.F. 40 I .17 N ' N 3.8 34-25 - II.F. 50 N .18 N N 5.5 25-25 - L3. 50 N .18 N I 3.5 -- - January 3.3. 53 N .18 N I! 3.8 25-29 - R.F. 70 H .18 N n 3.8 28.26 "’ InoF. 50 N. .18 H N 3.5 25 - 13.3. 50 N .18 N N 3.9 27 February 3.3. 40 N .22 N N 3.4 54-55 - R.F. 50 N .20 H N 3.7 34-55 - IcoF. 35 N .17 H N 5.4 45-43 '- Inn. 30 N .19 N N 5.5 45 - mall 3.3. 53 N .25 H N 3.3 42-44 '- R.P. 150 N .25 n N 3.2 ' 41-43 '- Inof. 70 N .20 N N 5.5 41 '- Lofio 50 N .21 N N 5.0 45-40 - April 3.3. 530 N .15 N N 4.5 40-40 - R.F. 1 .000 H .22 N N 4.5 35-53 - InF. 50 N .19 N N 4.5 55-57 - 11.3. 1,000 N .22 N N 5.1 59-55 - . Date of calving - 7/28/33 I-Ilv v. ---Q l... 1:. '.'.!'.. '.‘L. .._. '1'... .. _ - I ..‘...1 O u. . . \ u l ‘ . , .- I" O: .' l ‘; . ul- . - I -—" n J- . O - O. Q .". .'-.- l:'. I. '.- . . q .. . 1 o v o a t n O O O I D O t O . .. Table XVIII " Date for 00' 92* 52. : 310110003168: 3 :Phys. :Phys. : :M : 110nm :Qulr-zper c.c. 33.153» 01. :Exam. :Exan. :B.F. sch». :Strept :ter .33.} 1,000 x , j :0: Udderaot H111: : 5 meaning: NOW: 3.3. 30 N .14 N N 8.0 47 " R.F. 15.4 N .14 H N 7.3 M "' L.F. 25 N .15 N N 7.2 48-49 - Ia.R. 40 N .15 N N 8.0 49-50 - Decatur 3.3. 1.000 N .17 N N 5.7 48.51 " 3.3.. 100 N .17 N N 5.7 55-58 - I..F. 400 N .18 N N 6.7 57-58 - L.R. 700 N .15 N N 5.4 50-58 " February 8.3. 20 N .16 N N 6.1 60 - NJ. 22 N .16 N N 6.4 64-60 - LJ’. 53 N .14 N N 6.2 74-64 «- I..R. 55 N .19 N N 6.1 60 - larch 3.3. 500 N .17 N N 5.5 57-50 - R.F. 200 N .16 N N 6.9 56-58 - NJ. 100 N .17 N N 6.5 60-58 .. Inn. 80 N .17 . N N 6.5 67-66 - April 3.3. 30 N .10 N-S N 5.8 67-55 - 3.3. 50 N .10 N-S N 4.2 55.58 " L.F. 40 ' N .11 N-S N 3.8 55-58 - I..R. 32 N .11 N-S N 4.4 61-60 «- . Date of mung - 9/10/33 Table XIX - Date for CO! 246* November 11.3. 530 N .17 S N 5.4 48-49 - NJ. 1,000 V1.6 .17 S N 5.9 49-54 - L.F. 700 N .19 I H 5.2 -"-' " Inn. 800 FIG .17 S N 6.4 68-65 - mob 3.3. 20 n .15 34 N 4.4 '65 - L.F. 40 N .14 I N 4.4 65.65 - Inn. 50 N .15 I N 4.6 62-66 - April 11.3. 20 N .14 S N 4.2 40v - R.F. 18 N .16 S N 4.1 41 - LOP. 22 I .10 S N 4.1 41-41 '- I..R. 15.2 N .13 S N 4.2 41-39 - Deoaber R.R. 10 N .15 S N 5.0 51-53 - NJ. 10 N .15 S N 5.0 62-60 - I..F. 15 N .15 S N 5.2 57—58 - Ink. 12 N .13 S N 4.8 65 - February 3.3. 40 N .15 S N 4.2 42-40 - NJ. 20 N .15 S N 4.5 58-40 - LJ'. 30 N .15 S N 4.6 45-46 - IIORO 15 I .30 S H ‘.6 42 .'. . vat. of calving - 2/15/53 ... I. . ‘.‘ .9 _ r .=- .- . ...-... -..- l . _ I. __ . ., .--. Table xx - Date for Gov 197* 53. : 717940001708: 3 z a. a . 3 3:03:41 : loath mun-ape): c.c. :B.1'.B.: 01. gm. am. :B.F. sonar. :S'brept :ter spar 1,000 x s j :0: merge: N111: : :5 meeting: December k.k. 20 A N .16 N N 3.4 26-23 - RJ‘. 70 N .16 N N 3.2 23-23 - Ink. 60 N .16 N N 3.1 26-27 - L.R. 75 N' .15 N N 3.2 26-26 - Jammy k.k. 150 N .14 S N 3.6 25-27 - k.F. 100 N .15 S N 3.5 25-27 - Ink. 70 N .15 S N 3.4 35-33 - Infi. 50 N .15 S N 3.4 33-34 - February 3.2. 50 N .18 N N 3.3 26-26 - 3.3. 45 K .30 K N 5.2 27-35 - 10.3. - 50 H .15 I N 3.2 35-23 '0 19.3. 20 N .17 N N 3.4 35 '- Naroh k.k. 25 N .17 N N 3.2 27-27 - . 3.19. 50 I .15 N N 3.3 25-25 '- In.F. 40 N .15 N N 3.3 25-26 - 3.13. 60 N .16 N N 3.1 25-23 - April k.k. 35 N .20 N-S N 5.7 22-23 - 8.1“. 30 N .18 N-S N 3.5 23-25 - InF . 24 N . 18 '- N-S n 3 .5 27.26 "' L.k. 18 N .19 11-8 N 3.8 23-23 - ‘ Date of calving - 7/23/33 T3131. m - Data for 00' 132‘ Dem 3.3. 100 I .14 S N 5.0 68-71 - NJ. 70 Y .14 S N 4.7 70-70 - LJ'. 53 Y .14 S N 4.9 70-69 - Ink. 80 Y .14 S N 5.1 70-71 - February k.k. 10 N .10 N N 3.4 46-49 - 30F. 30 N .14 H H ‘ 5.3 51-48 - luF. 18 N .10 N N 3.7 45-44 - 11.3. 50 N .11 N N 3.4 50 - ”on 3.3. 22 N .1‘ N N 4.2 W '- R.F. 20 N .12 N N 4.2 32-31 - L.F. 12 N .12 N N 4.3 37-35 - Inn. 32 I .15 N N 4.3 57 '- " Date of calving - 12/9/32 .x. ,- |-| O I O O I v . o O O O O O:. 0.0 G O O. Q I. 0 fl 0 o o O Q . Ia. . o I 9 I O I 0 j. C u b O 6 O O I U I Q Q 0 D O i I O O .I I O U I I .J... Table XXII - Date. for Car 20* 54. : immortal: : M. : :Cur'd" : m SW8”: 0.0. 83.T.B.8 01. 8M. 831.3. 83.3. 3011”. 38131361)? star 8!! 1,000 3 3 j :0! Warm! N11]: 3. % mending: January 3.1: 4.0 N .16 N-S n " 6.7 59 - 3.! . 10 N .15 N N 7.1 47‘51 - " 10.3. 50 N .16 N N 6.5 50-52 - Inn. 50 N .16 N N 6.5 44-45 - Februn-y k.k. ' 30 N .11 N N' 4.4 39-41 - NJ. 100 N .12 N N 4.7 42-41 '- L.F. 40 N .12 N N 4.5 42-“ - Inn. 50 N .12 N N 4.7 40 " “13011 3.3. 32 N .1‘ N N 4.5 40-41 " R.F. 100 N .15 N n 4.4 32.31 "' L.F. 70 H .13 n N 4.0 37-55 "' 13.3. 53 N .14 N N 4.5 37 - April 3.3. 25 N .12 S N 5.7 41-45 '- RJ. 30 N .10 N N 5.0 43-11 - L3. 20 N .11 N N 5.5 41-44 - 11.3. 18 N .12 ‘ N N 6.5 . 40-42 - ’ Date or calving - 12/8/34 Table XXIII - Date. for Gov 2* November k.k. 25 N .15 N N 5.1 53-66 - R.F. 15 N .15 N-S N 5.3 57-55 '- L.F. 15 N .15 N-S -N 5.1 57-50 '- L.B. 18 N .15 N N 5.4 59-62 - Dem: Rofi. 53 N .15 N N 5.1 “_- " ' RJ. 40 N .15 N-S N 5.1 52-49 '- II.P. 50 N .15 N-S N 5.7 58 '- L.R. 50 N .15 N N 5.1 33-42 - January 3.3. 800 N . 16 N N 4.7 42-43 '0 RJ. 100 N .16 N N 4.8 414‘ '- L.F. 20 N .15 N-S N 4.3 45 '- ’ 13.11. 53 N .15 N N 5.0 43-45 - February R.k. 30 N .17 N N 4.7 48-50 - R.P . 500 H .17 N N 4.8 49"52 " In.F. 55 N .15 N N 4.3 45-57 '- Iven. 30 N .15 N _ N 4.9 45-40 '- Nareh 3.3. 100 m .18 N N 9.4 43-43 '- RJ'. 200 710 ' .15 N N 10.0 55-58 - luF. 400 m .30 N N 10.0 45-43 - I..k. 300 m .21 N N 9.2 44-44 - * Date of calving - 6/25/33 :\Z "- n a 0‘ _ . . [-1 -. ._. ..-. : : :- ': ..',.:: 3 _. .. ...----. ':.. ..'. '.".' . e-c 0|. . o I . '. I- ' ..‘. 10'. o n.- .'o- L:- ..'. 'I'I . I o'- '1' n a 0... o ... ' r . '. .'1. I: .__ . . . . .. , .‘. . ' e A ‘ o m. .'. ' ' '- 0 v o . o .I o o I' ' n I. a v e .- 9 0 ' '- ... o . o a: 0'. ..11 cl. .' 0 a ' I ' . .. ‘ .. .....- .--.— 55. '.t'lble XII? - Data for 00' 134’ 2 :Wocfies : : :Ws. : “gain-I : Month :QuAb-zper' c.c. :B.’I'.B.: 01. am. 3mm. :BJ'. sch”. :Strept ate: :per 1,000 a 8 fl :0! 116118230! [111: t 2 3390111113: November R.R. 50 N .15 N N 4.0 54-56 - 3.F. 500 N .15 N N 4.0 55-54 - IMF. 50 N .15 N N 4.0 53‘54 'I‘ 13.3. 12 N .15 N N 4.0 ‘52 - Decanber 3.3. 20 N .16 S N 4.7 49-49 - 3.F. 10 N .13 S N 4.9 72-70 - L.F. 120 N .18 S N 4.9 58-57 " 10.3. 15 N .17 S N 4.7 57-60 " January 3.3. 70 N .17 N N 5.2 45-53 '- 3.F. 100 N .17 N N 4.5 54-55 - II.F. .000 N .17 N N 4.9 ‘1'. O. 11.3. 700 N .17 N N 4.8 57 - April 3.3.. 800 N .18 S N 2.5 29-50 - R.N. 400 N .17 S N 2.4 32 '- In.F. 55 N .17 S N 2.5 52-32 «- L.3. 100 N .17 S N 2.5 29-50 - . Date or calving - 5/17/53 Table m - Data for Gov 193’ November 3.12. 20 n .16 s' n 3.2 4.5-4.0 - II.F. 10 N .16 S N 3.5 44—57 " 10.3. 12 N .15 S N 5.1 43-40 '- J 811113” 3.3. 100 N .15 N N 3.8 51-31 " 3.1“. 80 N .15 N _ N 3.7 32-32 - L.F. 50 N .15 N N 5.8 55-40 - ma. 75 N .16 N N 3.9 33-34. ." February R.B.. 20 N .10 N-S N 2.7 37.37 '- 3.F. 12 N .10 N N 2.7 58-40 - InF. 15 N .10 N N 2.8 40-41 - 13.3. 15 N .10 N N 2.9 41 '- m11 R.R. 50 N .18 S N 3.5 37.57 .‘. R.F. 20 N .19 S N 5.7 37 - Lofi. 20 N .18 S N 3.5 37-58 - * Date of calving .. 8/6/33 "'0 {I‘m 3 I .I. 6 56. . Table XXVI - Data. for Gov 87¢ : :WWfiOO: : a a. s . : 3:531 : loath mun-are: c.c. 33.1.3.3 01. :m. :Exm. 33.1% 30112:. :S‘brept 3159: 3199: 1,000 x z 5 :0! Uddemof H.111: : f mending: November 3.3 100 I .15 H-S I 9.0 27-26 - 3.]? 5,500 VDG .18 I H ‘- ~— 2 1.3 80,000 G . .33 I Flaked 7.6 15-13 x 1.3 5,000 1.0 .20 N—S H 8.2 27-26 1 March 3.3 300 N .17 N N 5.5 45 '- RJ‘ 530 VII-G .16 N N 5.1 41-41 - I»? 6,000 DG .17 11-8 N 5.1 42-43 - L.R. 1 .000 N .17 N N 5 .2 39-40 1 April 3.3 90 N .21 I N 5.0 19-19 - 3.? 700 ll .16 I H 4.9 17-16 x . Inn 200 N .18 I N 4.7 17-19 I * Date of calving - 3/30/33 23/281311. Table mu - Data. for ca. 167* 110er 3.3 ' 1,000 700 .27 I H 2.5 5- 5 x 3.? 5,000 15 .25 I N 3.5 34-37 X 11-6? 1,600 G .22 I N 3.5 31-29 X 1.3 12,000 VDG .27 I N 2.5 6- 6 x Decanber 11.3 60,000 VDG .29 I N 5.6 ~— 1 RJ‘ 3,000 N .25 I N 5.0 27-29 x II.F 1.400 m .25 I N 5.0 22-24 I 10.3 80.000 VDG .30 I N 3.3 .'. x larch 3.3. 11,000 Orange .25 N N 2.5 0- 0 x R.F 15 9 000 N .23 N N 4.5 51-49 I I..F 20,000 1! .20 N H 4.5 65-62 x Ink 200,000 Orange .21 N x 2,5 .. 1 April 11.3 100,000 7 .33 M G 1.3 0- 0 x R.F 50,000 71.0 .19 I N 3.6 28-30 x 1|.F 80,000 N .15 M N 3.8 34-23 I L.R 100,000 I .23 M G 1.3 0" 0 x ' Date of calving - 4/1/33 3/12/34 57. 1.51. mm: - Data for Gov 242. L I 3 50110003108: 3 x . :P . : :zi‘irtf : Honth 8M3”? 0.3. 5.153.: 01. 8m. SEX”. 83. F.8Ch”. :Strept star :Per 1,000 x x 5 :or Udderwf ml: 3 1 330201113: Ember 3.3 1,000 0 .23 I 3 4.8 ~— 1 2.3 600 m .20 s n 4.5 54-37 - IMF 5.300 G .23 I N 4.‘ ..- - 15.3 1,000 71.0 .23 1““ N 4.5 34-37 1 December 3.3 1,000 1.0 .22 I n 3.4 -- x 3.1? 4,000 n .17 1 n 4.6 38 - LoF 8.000 m .2‘ I N ‘.5 .'. x M 5,500 N .19 I H 4.7 58 - January R.B 180,000 LG .17 I N 4.5 58-40 x 1.3 1,000,000 12 .17 1 n 4,5 .. x , IIOR 500 I .17 I R 4.6 42 - February 3.3 1,400 IE .21 I N 5.5 42-59 x 3.? 200 I .17 I N 5.5 48-45 - 1.3 1,000 m .20 I n 5.5 - x 10.3 300 N .17 I N 5.4 42-48 - larch 3.3 15 ,000 G 027 I N 4. 5 ..- x 3.3 1,500 n .19 I n 4.4 42-59 .- 13.? 5.000 G .19 I N 4.0 '.- '- 1..n 4.000 n .20 I n 4.5 41-45 - April 3.]: 1,800 x .21 I n 4.0 ~— 1 3.? 700 I .21 I N 4.5 57-59 - II.F 500 N .31 I N 4.5 .'- I 15.11 300 N .19 I N 4.5 58-40 - . 0.1;. of 0.11553 - 1/5/35 Table mx - Data for 00' 4* February 11.3: 1.000 at .17 s n 4.0 55-55 - 3.]? 70 VII .14 S N 4.2 55-55 - In? 50 VII .15 I I 4.1 54 - Infi ‘ 52.4 VII .15 I N 4.5 58 - March 3.11 1,200 0 .21 s n 4.2 55 x 11.? 500 H .14 S H 4.8 56-57 - In? 400 H .15 I N 5.8 59-59 - 13.3 800 G .15 I N 4.8 58-59 «- mu 3.3 5.000 n .29 I n 4.5 29-51 x 3.? 900 N .17 l-S N 4.5 50-50 - I»? 500 H .18 S N 4.5 51-51 - 13.3 100 I .15 N N 4.5 51-55 - 2 Date of canine - 2/25 55 215 54 “nu..— ~<__ _.-u— _. ' . Q . ‘ Q’— .0 t I . Q - fl Q ._..* ( .'.. . -‘-, e -_. u . 9 'Q“ ..‘ C ‘._ ‘--I "' E -- t , ... Q .Q Q _ fl ‘ »- U U 41.6 \‘ \ -.‘ Q, “-9 -'-9 ..‘ C -1 Q t- --‘! ’ .-O -.’ I I c 58. Table m - 1351:. for 00' 12' 8 :jieuoocytes: 8 3mm : :C‘arct : loath mar-3P8: c.c. :B.'1'.B.: 01. 3m. 2m. 33.3.1511”. :Stropt :50: :Per 1,000 : z 5 :0! Uddarzor m1): 3 5 330% lumber 3.3 30 ' 3 .14 S N 5.6 55-60 - 3.1" 20 3 .14 I N 5.7 49-50 - IIOF 2,000 LG .17 I Elm 5.3 5m 1 L.3 40 N .14 S l 6.1 48-53 - December 3.3 53 n .15 11-3 3 4.5 27-26 - 3.? 5,300 N .15 I 3 4.7 31-33 - I..F 15,000 G .18 H I 4.5 26-25 x 13.3 159 N .16 N N 4.9 30-38 - January 3.3 100 N .16 N N 4.9 59-63 - 3.3 .800 , N .16 S N 4.7 67 - In}? 2.400 G .22 3 Elm 4.9 55-57 1 1.3 2,000 3 .17 N N 5.1 70 - February 3.3 700 n .13 N N 4.7 .41-40 - R.F 800 N .14- S N 4.5 35-54 '- L.F 4,000 G .23 S N 4.7 35-34, x 11.3 700 N .15 N N 4.4 33 . "’ men 3.3 1,000 n .18 ' 4.8 52-53 - 3.3 2,000 3 .18 4.5 33-34 .- I..]? 7,000 LG .25 4.5 30-31 x L.3 1,000 n .18 4.9 35-36 - April 3.3 1,000 N .21 3 H 5.1 -- - R.F 2.000 K .25 N N 5.2 27 "’ 1.1? 10,000 53 .28 I N 5.0 , 27-27 x 3.3 1,000 I .23 n 3 4.7 59-40 x 7 Date of calving - 9/27/33 Tuble XXII - Data. for cat 28‘ November 3.3 1,000 N .16 H 3 7.1 40-42 x 3.3 2,500 N .16 H n 7.1 45-47 x I..F 2,000 N .16 N N 7.4 43-43 x L.R 106 H .16 N N 8.6 52-54 - February 3.3 80 N .12 S 3 4.5 68-64 - 3.5 100 N .11 S H 4.6 58-58 - In? 50 N .11 S N 4.6 60-58 - Inn 30 N .12 S N 4.5 51 '- Naroh 3.3 4,000 N .17 S N 5.4 32-32 x 3.3 200 II .16 S N 5.0 28-29 x II.F 12° N .15 S H 5.‘ 28.28 X 1.3 1,000 N .14 S N 5.6 33-30 x April 3.3 40 N .18 S N 4.5 33-33 - 3.1? 50 H .16 S N 4.1 32-52 - In.F 30 N .18 S N 4.4 29-27 I 1.3 40 N .19 S N 4.6 32-32 - * Date of calving - 183:4 Table mm - Data. for Cow 71" 59. : fiawomeas : 3P 8. :P a. : :gécurd : [011th gQuar-xl’er c.c. :B.T.B.: 01. :Exam. 33103. :B. F.:Char. :Strept star :Per 1,000 3 .J :of undergo: mu : 5 :Reading: November 3.3 5,000 G .24 4.3 49-49 x 3.1? 5,000 G .24 4.7 44-44 x In? 550 N - .17 6.8 47-41 x I..3 1,590 IT .17 7.1 35-37 1 December 3.3 8,000 71.8 .23 7.3 39-46 x 3.3 7,000 71.0 .26 7.1 59- x 5.3 15,000 m .32 6.4 -- x 1.3 3,500 ‘ 71.8 .33 7.4 27-32 at January 3.3 2,000 N .20 5.0 33-34 x R.F 5,400 N .20 4.9 .- '1 I"? 7,600 N .20 7.0 49-46 x 15.3 7,800 I . 5.7 29 x . Date or calving - 11/25/32 Table mIII - Date on cow 66* November 3.3 1,600 N .16 N N 3.2 -- 1 3.3 100 ' H .16 N N 3.3 26 - 1.3 60 N .16 I N 3.2 39 - I..3 30 N .16 H N 3.5 48 - December 3.3 2,000 v1.0 .21 3-1 N 3.7 60-59 x 3.1? 100 N .17 S-I H 4.9 62-62 - I»? 70 H .17 I N 3.7 70-70 - L.3 40 N .17 I N 3.7 74-47 - February 3.3 400 m .24 N H 3.9 100-91 1 3.3 1,000 3 .19 N N 4.9 105-96 - ‘ L.F 500 3 .22 I 3 5.1 91-99 - 13.3 200 N .18 I N 5.5 103 - lhrch. 3.3 20,000 VLG .22 s N 5.6 55-57 x 3.3 550 m .20 H H 5.0 80-77 - I..F _700 no .23 S N 4.8 -- x 3.3 1,000 V1.8 .20 I N 5.1 67-65 1 April 3.3 900 D8 .51 S-I N 5.2 52-53 x 3.3 800 N .29 S N 5.5 65-62 x I..F 2,000 N .25 s N 4.9 -- ‘ - 5.3 N .22 I N 5.4 64-61 x ' Date or calving - 8/4/35 ...: a - l I .. .. n. 1 Q . . .... . .4. . o . m.. n \ .1 .0 Il- . . 0 u . . . . b u ~. : ... . . . n t o . .‘ . C l I ..' l. I- n .. . . .1 I O . . o. a I D .. .. - 0 O C I I II C . . u . . . In I o . . . _ _ _ v. n . u .I- I II- . . . . . . . . .. . . a .. .. _ ..-...- 60. Table mm - Data for Gov 171* : :fioomeas 8. 3M0. : {Laird t loath :Quar-grer 0.0. 33.3.3.3 01. 3m. 8m. - :B. 3.:01181'. :strept :50: :Per 1,000 : s % :0! Merge! H111! : % 33844158: February 3.3 5,000 m .11 I N 4.1 -- z 3.1" 1,600 N .10 I N 4.4 22-24 - I»)? 200 N .10 I N 4.1 24-23 - 13.3 5,000 0 .10 s N 4.2 ~— a: March 3.3 1,000 N .17 I N 5.4 22-21 x 3.3 700 N .17 I N 4.2 20-19 x I..F 500 N .14 I N 4.1 21-21 - I..3 2,000 V1.8 .14 S N 4.0 15-14 - Aprn 3.3 1,800 71.0 .17 I N 2.6 11-10 x 3.3. 2,800 71.8 .17 I N 2.4 11-11 x In? 100 N .15 I N 2.7 17-17 x I..B 50,000 LG .18 I N 2.8 11-11 x . Date of caring - 1/8/33 1/28/34 Table mv - Data for 001 172' November 3.3 200 N .16 I N 3.5 56-35 - R.F 530 I .17 11 N 5.8 57.37 I L.F 31m ' 1.3 5,300 G .27 M F 5.5 38-35 1 January 3.3 2,000 8 .24 I N 4.2 25-25 - 3.3 1,500 8 .20 I N 4.3 25-23 x I..F Blind W 3.3 4,000 7138 .30 M F 3.1 0- 0 1: Table XXXVI - Data for 00' 22” November 3.3 70 N .14 I N 5.2 62-65 - ' 3.3 106 N .14 I N 5.2 62-65 - L.F 53 N .14 I N 5.3 57-62 - I..3 30 N .14 I N 5.1 59-64 - Decanber 3.3 50 I .14 S H 5.1 37 '- 11.]? 100 71.8 .17 S N 5.8 38 - I..F 80 VLG .16 S N 5.8 45-45 - 1..3 53 N .14 S N 5.4 42-45 - January 3.3 55 N .14 S N 5.6 34-32 - 3.]? 1,500 N .17 s N 6.0 -- - I..F 100 N .17 S N 5.3 35-32 - - I..3 70 N .17 S N 4.9 38-38 - February 3.3 40 N .18 N-S N 4.8 64-70 - 3.? 400 N .20 N-S N 4.8 """"’ " 13.3 100 N . .22 151-8 N 5.1 74-70 - DJ! 40 N .19 N-S N 4.9 72-76 - * Date of calving - 4/18/33 u Date of. calving - 5/10/33 . . . -n .'- '- \ u .'v - .- .. 0 \ \ \ . . Qw'rf .. ;.. Table XXXVII - MATHEMATICAL CALCULATIONS m Chlorides for the Normal Group 61. fird : z 8 Difference : a Character : Chloride. : Frequency : from : 12 : 312 Range .PerCent : :lteanorX: : 5. 0-30 0.171 27 1.012 .000144 .003880 30-60 0.159 90 .000 .000000 .000000 50 and up 0.152 55 -.007 .000049 .002695 172 172/w .006575/.000382 lean -.159 per cent Standard error -.019 (equals square root of .000382) a The positive to streptococcus cons of infected group 0-30 0.219 32 .011 .000121 .003872 30-50 0.195 23 .013 .000169 .003887 58 58/ .008122/.0001400 Mean -.208 per cent Standard error 0.012 (equals square root of .0001400) 2 The negative to streptococcus cave of the infected group 0-30 0.165 10 .010 .000100 .000100 30-50 0.161 41 .006 .000036 .001476 50 and up 0.134 17 .021 .000441 .007497 68 887 .009973/.00147 Mean .155 per cent Standard error .012 (equals square root of .000147) The difference of the means between A and B is .049 .012 x 2 g .024 To be significant the difference of the means must exceed the standard error by two or more times. The difference of the means between A and 0 is .040 .049 exceeds .024 .020 x 2 3 .040 This is one the border line of being significant. 62. Curd test Figure 1 . Knife (Note the metal plunger which is inserted in the hollow shaft during coagulation of the milk). 63. ROOM USE ONLY “1135 “M“ v '1 r $312531» ' ”’m , V ' , - ~‘ Ml“HM3AF STAT or.“ .. ’ " " 1;. ‘ ”’53.: ‘1‘} m“ ‘\ h . “‘ VH3! 11219: 5w _3 0304 If I l BRARIES ..‘ TIM!!! — ; : K 43' were — .. e.- *5 .. ..’Jy) 025" 21;” ‘ .‘- 1 ”2,3...“ p .