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University

 

UREA UTILIZATION BY
THE YOUNG DAIRY CALF

by

Gail D. Riegle

AN ABSTRAC

Submitted to the School of Graduate Studies of Michigan
State University of Agriculture and Applied Science
in partial fulfillment of the requirements
for the degree of

MASTER OF SCIEICE

Department of Dairy

1960

Approved //<?:/f7 574é;19~é Effc»

ABSTRACT

A study was carried out to determine the ability
of young calves to utilize milk replacers supplemented
with urea. Twenty-four male Holstein calves were as-
signed to three milk replacer diets. A basal ration
containing 10% crude protein was compared to rations
containing 18% crude protein. One of the 18% crude
protein rations was supplemented with milk proteins
and urea supplied the supplemental protein in the
other. The calves were weaned at ten days of age.

At twenty days of age, the eight calves comprising
each replacer group were randomly divided into sub-
groups A and B, of four calves each. The calves in
sub-group A were fed an increasing amount of milk
replacer. The calves in sub-group B were fed lesser
amounts of milk replacer but were allowed free access
to a urea supplemented calf starter. Neither group
were allowed hay during the study. Digestion studies
were conducted on all calves at 15, 29, and #3 days

of age. Chemical analyses were conducted to determine
nitrogen balance, apparent protein digestibility, ap-
parent dry matter digestibility, blood urea, and blood

non-protein nitrogen values.

Calves fed the urea supplemented milk replacer
were found to have significantly greater (R=<0.0l)
values for nitrogen balance, and apparent protein di-
gestibility. Dry matter digestibility values increased
with age for calves in sub-group B, fed the calf starter
as a dry feed, and decreased with increasing age for
calves that were continued on the gruel diet alone.
Blood levels of urea nitrogen and hon-protein nitrogen
'were found to consistantly decrease with age. In most
instances the calves fed the urea supplemented milk
replacer had greater blood urea nitrogen and blood non-
protein nitrogen values than did the calves fed either
of the other two experimental rations.

The data assembled from the digestion studies in-
dicated that the young calf could utilize urea as a

dietary source of nitrogen at 15 to 19 days of age.

UREA UTILIZATION BY
HE YOUNG DRIRY CALF

by
Gail D. Riegle

A THESIS
Submitted to the School of Graduate Studies of Kichigan
State University of Agriculture and Applied Science

in partial fulfillment of the requirements
for the degree of

MASTER OF SCIENCE

Department of Dairy

1960

TABLE OF CONTENTS

Acknowledgements .

Introduction . . .

Review of Literature .

Experimental Procedure

ReSUlts . . . . .
Part I . .
Part II. 0

Discussion . . . .

Summary . . . . .

Literature Cited .

.Blood Studies

.Digestibility Studies

Page

21
30
30
36
60
67
69

Table

LIST OF TABLES AID FIGURES

I. Milk and Replacer Feeding Schedule,

C\ \n -¥' UJ [U
0

7.

9.
10.
ll.
12.
13.
1H.
15.

Figure

Composition of Experimental Milk Replacers

Composition of Experimental Calf Starter.

Chemical Analysis of Feeds Fed . .

Digestion Study Schedule. . . . . .

Nitrogen Balance-Individual Calf Values.

Nitrogen Balance-~Statistical Analysis.

Dry Matter Digestibility--Individual Calf Values #3

Dry Hatter Digestibility--Statistical AnalysiSw

Protein Digestibility--Individual Calf Values

Protein Digestibility-~Statistical Analysis

Blood Urea-~Individual Calf Values.
Blood Urea-~Statistical Analysis. .

Blood NPN--Individual Calf Values

Blood NPN--Statistical Analysis .

Average Nitrogen Balance Values 0 .

1+5
1+6
48
49
51
52
54

Page

Average Apparent Dry Matter Digestibility Values 56

Average Apparent Protein Digestibility Values

Average Blood Urea Values 0 - . ~ .

Average Blood NPN Values- - . . . .

57
58

ACKNOWLEDGEMENTS

The author wishes to express his appreciation
to Dr. N. P. Balaton, Head of Department of Dairy,
for award of the Graduate Assistantship and provision
of the facilities for conducting the study; to Dr. C.
A. Lassiter, Professor of Dairying, for suggesting
the problem and his continued interest and guidance
throughout the study; to Dr. C. F. Huffman, Professor
of Dairying, for his suggestions and counsel; to Dr.
R. S. Emery, Assistant Professor of Dairying, for as-
sistance in the chemical analysis of the samples; to
Dr. R. L. Baten, Professor of Statistics, for assist-
ance in the statistical analysis of the data; to Mr.
L. D. Brown, and Mr. J. P. Everett for advice on the
details of conducting the experiment; to Mr. Ralph
Reid and Mr. L. Reid for assistance in caring for the
animals; to all the graduate students of the dairy de-
partment for their advice and suggestions throughout
the trial; and to my fiancee, Miss Barbara Welch, for

her interest and encouragement throughout the study.

INTRODUCTION

Many studies have been carried out determining
the relative value of urea as a dietary source of
protein for mature ruminants. When properly fed,
its generally favorable responses are well known and
accepted. However, the age at which the young calf
can efficiently begin to utilize urea has not been
agreed upon.

Most workers agree that on a limited milk feed-
ing program, the young dairy calf is mature in rum-
inal function; as measured by fatty acid production,
at about six weeks of age. Other work has shown that
the rate of ruminal development, measured by papillary
development, is to a large extent determined by the
relative amounts of milk offered in the calf's diet.
When dry feeds were introduced into the young calf's
diet to supplement or replace the milk being fed,
some ruminal papillary development was measured at
12 to 20 days of age. The relative amount of the
deve10pment was seemingly dependent on the amounts
of forages or grains being consumed.

Recent research in urea feeding to young dairy

calves indicated that under a limited milk feeding

-2-

program, the calf was able to utilize urea efficient-
ly by h to 5 weeks of age. In this work no attempt
was made to determine the earliest possible age at
which the calf could begin to utilize the non-protein
nitrogen supplied by urea.

The present research was designed to study the
early utilization of dietary urea by the young dairy
calf.

A REVIEW OF LITERATURE

The role of urea in ruminant nutrition has re-
cently been extensively reviewed by Du Pont De Nemours
and Company (1958), and in an earlier review by Reid
(1953). The reviewers indicatedthe general acceptance
of urea, when properly fed, as a source of dietary ni~
trogen for mature ruminants.

The use of urea as a source of protein for dairy
heifers has been investigated by several workers.
Lassiter gt; g1; (1958), working with dairy heifers,
compared concentrate rations containing 3, 5, and 7%
urea. They found a decrease in daily gain and feed
consumption for each increase in the level of urea
fed. Additional studies reported by Lassiter (1958)
indicated that the heifers could utilize concentrate
rations containing as much as 5% urea when sulfur sup-
plementation was provided. They found that heifers
fed concentrate rations containing 7% urea did not
grow satisfactorily regardless of sulfur supplement-
ation.

In tests conducted by Parham gt;_g1‘,(l955), 19
to 33 months old heifers showed no significant de-

crease in gains when ammoniated molasses and urea sup-

-h-

plied 18% of the ration crude protein. However, more
energy per unit of gain was required by the animals
receiving urea.

Bartlett and Cotton (1933) reported that dairy
heifers 7 to 17 months of age utilized urea as well
as conventional vegetable proteins. They also observ-
ed that the urea supplemented heifers gained signifi-
cantly more than heifers fed a low protein control
ration.

However, Hart g§;_glg (1939) working with dairy
heifers, observed that when 70% of the dietary nitro-
gen was in the form of urea, diuresis along with in-
creased levels of blood urea occurred. These workers
concluded that less efficient utilization of the urea
protein was obtained. Most authors agree that when
feeding urea to functionally mature ruminants urea
nitrogen can replace up to 1/3 of the total protein
in the ration without significantly reducing utiliz-
ation efficiency.

Experimental data concerning the utilization of
urea for dairy calves younger than 6 months of age
are not as plentiful. Urea utilization by young
dairy calves was studied by Brown gt; g1;.(1958).

-5.

It was reported that a 12.1% protein equivalent calf
starter (M6.3% of the nitrogen supplied by urea) was
adequate for above normal growth of calves fed a limit-
ed milk ration for #2 days. Nitrogen balance data
indicate that nitrogen retention increased signifi-
cantly with age. Also they found that the blood urea
nitrogen and plasma protein levels were significantly
higher at 2 days of age than M, 8, or 12 weeks of age.
Earlier work by Brown gt; 3;; (1956) compared a
6.7% crude protein calf starter with a 15.1% crude
protein urea supplemented starter (urea contributing
5H.2% of the total protein) and a 15.2% crude protein
conventional milk protein supplemented starter. The
calves grew at comparable rates during the first six
weeks when milk was being fed, after which the calves
on both supplemented rations grew significantly faster
than the calves fed the low protein rations. Differ-
ences between the urea-supplemented and conventional
protein groups as regards average daily gain, total
starter consumption, or pounds of feed required per
pound of gain were not significant. These workers
observed that the calves on the urea ration digested

a lower percentage of crude fiber than those fed the

-6-

conventional protein supplemented diet. Although

the results of these two trials were influenced by
the milk feeding, they indicate that a portion of the
nitrogen requirements of the young calf can be sup-
plied by the addition of urea to the ration.

Urea utilization trials on young non-ruminants
generally have not given favorable results. Taylor
and Ringer (1913) in their work with dogs, Hanson and
Ferrin (1955) with hogs, and Liu 23;.il; (1955) also
working with hogs reported that little if any nutrition-
al benefits are derived from dietary urea. Braude
(19H2), in a study of rations utilizing synthetic pro-
teins, also reported unfavorable results when urea
was incorporated into swine rations.

An extensive study on urea utilization by swine,
conducted by Hays g§g_§1; (1957), demonstrated that
when urea was incorporated into the diet, feed efficien-
cy was significantly reduced, feed required per pound
of gain increased linearly as the percentage of urea
in the ration was increased, and the percent of ni-
trogen retained decreased as the level of urea in the
diet was increased. The replacement of 10 or 20% of

the protein with urea significantly reduced the rate
-7-

of gain.

Kress and Marcy (19HO) fed urea to rats and re-
ported almost complete recovery of the urea in the
urine and feces.

Most studies of urea utilization in poultry have
yielded negative results. Slinger g3; g1; (1952) re-
ported that growth rates in chicks were not improved
by the addition of urea to diets suboptimal in protein
level.

Conversely, in tests conducted by Liu gt; §_l_,_
(1955) on growing swine, a small, but definite amount
of urea labeled with N15 was absorbed into tissue pro-
teins. Grafe g3; §l&,(l9l3) reported that the addition
of urea to the diets of swine increased nitrogen re-
tention.

Rumen development and the utilization, digesti-
bility, and retention of non-protein nitrogen has been
studied extensively in recent years. Conrad and Hibbs
(1953 and 195“) conducted several extensive studies
concerning ruminal development by young dairy calves
on high roughage diets. Their data indicatedthat
feeding of high quality roughages to the very young

calf enhances the development of types of bacteria

-8-

that are numerous in the mature rumen, and also in-
creases the production of volatile fatty acids in
the rumen. This work indicated that the rumen is
functionally mature after 6 weeks of age.

According to Lengemann and Allen (1955), there
are great differences in rumen contents between 1 and
2 month old calves. They report that the development
of adult-like rumen function is gradual and starts
early in the life of the calf. These workers found
that many of the changes were dependent on the nature
of the diet and the amount and kinds of bacteria in-
gested by the calf. Using fatty acid production as
a measure of development, they observed a stabili-
zation of the relative percentages of acetic, butyric,
and propionic acids by the second month of age. They
concluded that at 6 months of age the rumen contained
percentages of the volatile fatty acid that were high
enough to consider the rumen adult in function.

McCarthy and Kesler (1956), working with l to 15
weeks old Holstein calves, found that blood glucose
decreases concurrent with increases in the levels of
the blood volatile fatty acids with increasing age.

This experiment showed a transition in the metabolites

-9-

involved in energy metabolism. At birth and for a
short time afterward, the calf relies on glucose for
its major energy needs. As the calf matures, the in-
crease in volatile fatty acids is probably the result
of increased rumen activity. It was found that all
factors began to shift at 1 week of age. The levels
of volatile fatty acids in the rumen fluid and the
ability or this fluid to digest cellulose (by 1 week
of age) indicated at least a partially functioning
rumen had been developed. Blood volatile fatty acids
underwent their largest increases in concentration
during the first 6 weeks. At this stage the concen-
trations were sufficient to contribute considerably
to the metabolic needs of the animal. These tuthors
concluded that mature development of the rumen is
completed at 5 to 6 weeks of age.

Kesler gt;_§1&,(1951) found a pronounced increase
in weights of rumen contents and tissues between the
ages of 32 and #2 days. It appeared that rum-
ination had begun at 6 weeks of age.

That calves have at least a partially functioning
rumen at an early age was also observed by Swanson

et. al. (1958). It was reported that at 6 to 1% days

-10-

of age, 79% of the Holsteins and 6h% of the Jerseys
studied were ruminating. By 20 to 28 days all the
Holsteins and 91% of the Jerseys were ruminating.
Examination of rumen contents showed that 11 calves
that were killed from 1% to 22 days of age had been
ruminating normally and 6 that were killed from 12
to 15 days had not been ruminating effectively. It
was reported that effective rumination commenced in
the hand-fed calf before it was 3 weeks of age.-
Work by Martin gt;_g1&_(l959) illustrated that
the young calf was able to absorb volatile fatty acids
from its digestive tract by 3 weeks of age. It was
reported that while it is possible for the calf to
absorb volatile fatty acids at an earlier age, the
absorbing ability is enhanced by the developing rumen
mucosa. It was also observed that if the young calf
was fed a lactose-free diet, its blood sugar level
remained constant as :in the shole milk fed calves.
Flatt and co-workers (1958) introduced plastic
and cellulose sponges into young calves' rumens. The
sponges alone did not induce papillary deve10pment of
the rumen, but when solutions of purified preparations

of the sodium salts of acetic, propionic, butyric, and

-11-

lactic acids were introduced, marked development was
stimulated. These authors concluded that the end-
products of rumen fermentation, rather than the
coarse nature of food cause rumen papillary develop-
ment.

Sander §t&.al&.(l959) added sodium acetate,
sodium propionate, sodium butyrate, sodium chloride,
and glucose to the rumens of young dairy calves and
observed the effects on rumen mucosal development.
The administration of sodium butyrate or sodium pro-
pionate caused marked development, however, adding
sodium acetate, sodium chloride, or glucose caused
very little mucosal development. It was hypothesized
that rumen papillary deve10pment was a result of the
metabolism of certain compounds by the rumen wall and
their effect on blood flow supplying the rumen.

Development of rumen papillary epithelium was
used as a criterium for rumen function by Flatt,g§L El;
(1956). It was reported that milk-fed calves had the
least rumen development when compared to animals fed
solid feeds.

Brownlee (1956) also studied papillary develop-

ment as a measure of rumen development. Newborn and

-12..

week-old calves kept on a milk diet did not show de-
ve10pment of rumen papillae for 13 weeks. In con-
trast, week-old calves on a diet of milk plus hay,
grass, or concentrates gave an increasing amount of
papillary development. Since it was also found that
calves kept on a milk diet, increased the weight of
their rumen contents as much as 6 times the original
weight and, did not have any papillary development,
weight of rumen contents considered alone, is not a
true measure of rumen development. Roughage alone
was not a factor in determining the rate of develop-
ment of rumen papillae. It was reported that the de‘
ve10pment was determined by the energy value of the
foods or the rapidity with which they were broken
down into absorbable fractions.

In further studies by Lengemann and Allen (1959),
liberal milk feeding delayed the establishment of adult-
like rumen microflora content as compared to limited
milk fed calves. A rapid decrease in the aerobic
bacterial types, an increase in total numbers of bac-
teria, and the establishment of protozoa types were
apparent within the first 3 weeks of age. The total

numbers of bacteria were low until the animals had

-13-

become established on diets containing solid feeds.
Calves that were continued on milk diets consistantly
showed high aerobic bacteria counts. Conversely, the
calves that were fed solid feeds at an early age, de-
velOped mature levels of protozoa by 5 weeks of age.
These calves achieved an acetic acid content of 63 mM
per liter between the 6th and 7th week, 18.1 mM per
liter of propionic acid by the 3rd week, and lh.5 mM
of butyric acid per liter by the nth week.

Harrison 23; £1; (1957) investigated retrogression
of the reticulo—rumen when calves were changed from
a hay-grain ration to a milk diet. When this substi-
tution was made on 3 months old calves, the reticulo-
rumen and omasum retrogressed to an undeveloped con-
dition similiar to that of a milk fed calf. This
work along with Conrad's (1953 and 1954) demonstrates
an influence of diet ingredients upon rumen develop—
ment and function.

The digestibility, retention and utilization of
urea and other non-protein nitrogen compounds have
recently been studied extensively by various researchers.

Wegner (l9kl) reported that the rate of urea con-

version to protein within the rumen decreased when the

-14-

crude protein content of the ration exceeded 12%. The
extent of urea conversion was decreased when the crude
protein level of the ration exceeded 18%.

Meiske (1955) observed no difference in growth or
weight gain resulting from feeding urea in combin-
ation rations to growing lambs.

King (1957) reported that when molasses was sup-
plemented with urea, the digestibility of the molasses
in the supplemented rations was considerably increased.

Belasco (1955) reported that the amount and type
of carbohydrate used for energy affected urea utili-
zation and the distribution of volatile fatty acids.
These data indicated that the addition of starch to
the fermentation resulted in better urea utilization
and higher fatty acid production than cellulose.
Starch introduced in vitro yielded more valeric, bu-
tyric, and acetic acids, and less propionic acid than
cellulose. The amount of propionic acid produced was
in direct proportion to the amounts of cellulose, urea
utilization was as extensive as achieved by starch
addition. When either starch or dextrose was intro-
duced at high levels, cellulose digestion was in-

hibited. This was most pbnounced with dextrose.

-15-

Dextrose added at high levels also gave sharp increases
in levels of valeric and butyric acids which were com-
pensated by decreases in levels of production of pro-
pionic and acetic acids.

Earlier work reported by Belasco (195“) indi-
cated ammonium salts of formate, alpha-keto-glutarate,
malate, and especially succinate and lactate produced
higher rates of nitrogen utilization and lower free
ammonia levels than urea or other ammonium salts studied.
Belasco (1954) postulated that these salts enter into
some biosynthetic process stimulatory to nitrogen fix-
ation by rumen microflora. Using cellulose digestion
and the lowering of free ammonia levels as indications
of availability, Belasco (195“) reported that quanidine
salts, carbonates, hydrochloride, and acetate were ef-
fective as sole nitrogen sources in vitro. When amides
were introduced, they also produced low levels of free
ammonia in the system along with a supply of biologi-
cally available nitrogen formed by normal ruminal bac-
terial growth.

Bell gt; El; (1957) working with lambs reported
a significantly greater digestibility of crude pro-
tein and lower digestibility of ether extract for

-16..

urea supplemented rations as compared to cottonseed
meal supplemented rations.

Byers (1957) studied digestion of cows fed all
corn rations with and without urea supplementation.
When urea replaced 3.5% of the ground shelled corn
for lactating cows, the digestibility coefficients
for dry matter, protein, fiber, and nitrogen-free ex-
tract all favored the urea ration. However, only
the increase in protein digestibility was significant-
ly greater.

Hatfield g3; El; (1955) observed a slightly
higher digestibility coefficient of nitrogen when
urea was fed. However, when compared to biuret and
soybean meal supplemented rations, lower digestibility
coefficients for ether extract and crude fiber were
reported.

Gallop (1952) observed higher digestibility of
urea supplemented rations at all levels of feeding.

In order to test the effect of rumen fermentation,
Muhrer g3; g1; (1933) fed swine rations containing
forages and urea that had been fermented in an
artificial rumen. The pre-digested rations im-

proved daily gain and feed efficiency. The authors

-17-

reported that a ration for non-ruminants can be im-
proved by fermenting some ingredients in an artificial
rumen.

In their work with carotene and vitamin A utili-
zation, Gallop gt; g1; (1950) reported that urea was
without effect on vitamin A utilization. Bell gt; El;
(1955) observed that urea feeding to lambs had no
noticeable effect on the retention of calcium, phospho-
rus or nitrogen.

Conversely, Levy and Donker (1955) working with
young dairy steers reported that urea feeding compared
to cottonseed meal supplementation considerably re-
duced daily gain and feed efficiency. In this work
urea composed 33% of the total protein of the ration.
Embry and co-workers (1957) reported no significant
differences in digestibility of nutrients in rations
containing soybean meal or linseed meal, with or with-
out urea (0.9% of the total ration). When 5% lard
was added to the diets the urea supplemented rations
gave significantly greater digestibilities of crude
protein and ether extract, but the digestibility of
fiber and nitrogen-free extract was decreased.

Gallop et. a1. (1952) conducted nitrogen balance

-18-

studies in lambs using urea supplemented rations. As
the roughage levels decreased, urea nitrogen retention
increased. When urea was added above 30 to 40% of the
total crude nitrogen, nitrogen retention decreased.

A study of the nitrogen balance in steers was made by
Hatfield _e_t__._ gig (1955). Rations containing urea,
soybean meal, and biuret were compared. Soybean meal
was only slightly higher than urea in terms of nitrogen
retained, but was significantly greater than the biuret
supplemented ration.

In contrast, studies by Ellis and co-workers
(1955) indicated urea supplemented rations resulted
in significantly less nitrogen retention as compared
to soybean or blood fibrin supplemented rations.

This feeding trial illustrated superior utilization
of "true" protein as compared to urea by sheep.

In general, the literature illustrates that there
is little conclusive evidence which indicates the exact
age that it is possible for be young calf to begin
to utilize a synthetic nitrogen supply. There are
also many ration ingredients that influence the calf's
ability to utilize these non-protein nitrogen com-

pounds that need be considered when formulating a

-19..

non-protein nitrogen supplemented diet for the young

calf.

-20..

EXPERIMENTAL PROCEDURE

Selection and Assignment of Animals

Twenty-four male Holstein calves were used in
this study. The calves were obtained from the uni-
versity herd and several local dairymen. The calves
were assigned to the different milk replacers randomly
as they became available. Towards the end of the ex-
periment, the new calves were assigned according to
body weights in an attempt to equalize the initial
weights among the groups as much as possible. Since
similar feed consumption rates were of considerable
importance in the experiment, any calf that refused
to eat due to illness or other abnormalities was re-
moved from the experiment and another animal substi-
tuted in its place. The only prerequisite for as-
signment was normal health and appearance.

Feeding and Management

Calves were left with their dams for 48 hours
after birth. The calves were then removed from their
dams, fasted 12 hours, weighed, and assigned randomly
to an experimental ration. The feeding schedule for
the calves is presented in Table l. Hilk feeding was

terminated at 10 days of age to allow a digestion study

-21..

TABLE 1
MILK AN' REPLACER FEEDING SCHEDULE

 

 

Age Milk Water Replacer
Group A Group B
------------------ lbs.———-—-------—----

0-2 days Dam

3-7 days h.0 4.0 0.6 0.6

8-10 days 2.0 6.0 1.0 1.0

20-33 days - 12.0 1.6 1.0

H8-56 days - 12.0 2.0 0.#

 

to be made, without the influence of milk, before the
calves reached 21 days of age. The milk replacers
were fed as a gruel in the amounts indicated in

Table 1. At 20 days of age, the 8 calves assigned

to each milk replacer were divided into 2 sub-groups
of h calves each. Sub-group A was continued on a milk
replacer diet without any dry feed for the duration

of the experiment. The calves in sub-group B, at 20
days, were fed reduced amounts of their respective

milk replacers as well as a urea supplemented (urea

-22-

h9.h% of the total protein) calf starter which was
fed ad libitim. Both sub-groups were removed from
the experiment at 56 days of age. Hay was not fed to
either sub-group during the trial.

When the calves were not in digestion stalls,
they were housed in small individual stalls bedded
daily with wood shavings.

Feed Formulation

The formulae for the 3 milk replacers used in
this experiment are presented in Table 2. Milk re-
placer no. Hl served as the low protein control ration.
Milk replacer no. 4% utilized milk proteins for the
supplementary nitrogen. In milk replacer no. 45, the
supplemental protein was urea (46.9% of the total
protein). The protein content of the respective re-
placers was adjusted by varying the proportions of
cerelose, dried whey, and dried skimmilk.

The milk replacers were mixed in quantities suf-
ficiently large enough to last the duration of the
trial. They were stored in fiber barrels to prevent
contamination and to protect the mixed replacers from
moisture.

The formula for the calf starter used by sub»

-23-

COTPOSITIOH OF E} ERIXEYTAL MILK REPLZCERS

 

 

 

Ingredient H1 Replicer #5
---------- lbs.—--------------—

Dried skimmilk 5.0 35.0 5.0
Urea (275%) - - 2.8
Dried whey ' 55.0 37.0 5h.6
Cerelose 28.9 16.9 26.5
Distillers solubles 5.0 5.0 5.0
Beet pulp 3.0 3.0 3.0
Trace salt 0.5 0.5 0.5
Dicalcium phosphate 2.0 2.0 2.0
Aurofac 10 0.5 0.5 ‘0.5
Vit. & mineral conc.* _JQ;1 ._J;;1 0.1

TOTAL 100.0 100.0 100.0

Calculated chemical analysis of ingredients (percent)

Crude protein 10.4 18.0 18.0
Protein from urea - - H6.9
Lactose H0.0 h3.0 39.7

 

*Nixture contained:
Vitamin A conc. 20,000 U.S.P. units/g .........20g.
Irradiated yeast, 9,000 I.U. vitamin D/g .......5g.
Cobaltous sulfate (CoSOu-7H20 ..................3g.
CUPriC sulfate (CuSOu°5H20) ....................2g.
Ferrous sulfate (FeSOn-7H20) ..................llg.

-24-

TABLE 3

 

 

COMPOSITION OF EXPERINENTAL CALF S ARTER
Ingredients Starter
lb.

Ground yellow corn 1,000.0
Crimped oats 300.0
Urea (275%) 59.0
Corn distillers solubles 100.0
Cane molasses' 133.0
Dicalcium phosphate 20.0
Trace salt 20.0
Vit. a a D 1.5
Aurofac 10 3.0
Corn starch 363.5

TOTAL 2,000.0

Calculated chemical analysis of ingredients (percent)
Crude protein l6.h

Protein from urea h9.h

 

group B is presented in Table 3.

Representative samples of the replacers and

starter were obtained f

or chemical analysis. The

chemical analysis for the respective feeds is pre-

sented in Table h.

 

CHEKICAL ANA

u
LYSIS OF FEEDS FED

TABL

Lil

 

Replacer Starter
$1 1+? 1+5

 

Ash

Crude fiber
Ether extract
Water

Protein

Nit.-free-extract

 

 

Diges
Each of the 2% cal
digestion trials. The

tion Studies
ves underwent 3 individual

time schedule for the digestion

studies is indicated in Table 5.

-26..

T [LB LE 5
TION STUDY SCHEDULE

 

 

Age Handling
2 days weaned from dam

12 days in digestion stall
’ 15 days collection begins

19 days collection ends

26 days in digestion stall

29 days collection begins

33 days collection ends

#0 days in digestion stall

#3 days collection begins

47 days collection ends

56 days ' calf off trial

 

A standard 3-day adjustment and a 4-day collection

period was utilized in this study.

used to make the collections.

Frame constructed sheep digestion stalls were

The movable stanchion

allowed length adjustment to compensate for variations

in respective calf ages and lengths. The stalls were

equipped with a double screen arrangement under much
of the area where the calf stood to allow for urine
collection. The screens funneled into gallon glass
jars which were used for the urine collections. Feces
were collected in metal pans attached to the rear of
the individual stalls.

Urine and feces were measured and sampled daily.
Ten ml. of toulene and 5 ml. of HCL (diluted 1:1 with
water) were added to the urine bottles daily to pre-
vent the loss of nitrogen. Five percent aliquot
samples of the urine were taken daily for chemical an-
alysis. These samples were kept under refrigeration
during the collection period and until the time that
the nitrogen content was determined. The feces were
weighed daily and transferred to lard cans which were
stored under refrigeration. At the end of the col-
lection period, a sample was taken of the b day com-
posite which was subjected to dry matter and nitrogen
determinations.

Blood Studies

Forty ml. jugular blood samples were taken from

each calf at 2, 12, 26, and #0 days of age, the ages

that the last 3 samples were taken corresponding to

-28-

the dates the calves entered the digestion stalls.

Blood urea nitrogen and blood non-protein nitrogen

values were determined on the plasma of each sample.
Analytical Procedures

Milk replacers and calf starter: dry matter, crude
fiber, ether extract, water, protein, and nitrogen
free extract, (Association of Official igricultural
Chemists, Official Methods g: Analysis). 1955.

Feces: dry matter and total nitrogen (kjeldahl),
(Association of Official Agricultural Chemists,
Official Methods 9; Analysis). 1955.

Urine: nitrogen (kjeldahl) (Association of Official
Agriculture Chemists, Official Methods of Analysis).
1955.

Blood: urea nitrogen and non-protein nitrogen,
(Hawk, Oser, and Summerson, Practical Physiological
Chemistry). 1954.

 

Statistical analysis of data: (Snedecor, Statistical
I‘iethOdS) o 1956.

 

-29-

RESULTS
PART I -- DIGESTIBILITY STUDIES

The data obtained on individual calves with
accompanying graphs and statistical analysis of the
digestion studies are summarized in Tables 6 to 11
and Figures 1 to 3.

Nitrogen Balance

During the first digestion period the calves fed
milk replacer no. #1 (the low protein basal ration),
showed a negative nitrogen balance of ~2.29 grams per
day (Tables 6 and 7 and Figure 1). In contrast, the
mean nitrogen retention values for replacer no. an
was 3.83 grams and for the urea supplemented replacer,
no. #5 was %.67 grams per day. The nitrogen balance
means for replacer nos. 4% and #5 were both signifi-
cantly higher (B=<0.0l) than the mean for replacer
no. 41. There was no significant difference between
the means for replacer nos. HM and #5.

During period 2 the nitrogen retention values
for the calves not fed starter, sub-group A, for re-
placer nos. al, HM, and M5 were 3.39, lO.#6, and 2.73
grams per day, respectively. The mean for replacer

no. 4% was significantly greater (P=<D.Ol) than either

-30-

replacer no. #1 or #5. The nitrogen retention values
for the calves that had free access to an urea sup-
plemented calf starter (sub-group B) were 2.07 grams
per day for replacer no. #1, 6.81 grams per day for
replacer no. #4, and 5.#l grams per day for replacer
no. #5. Analysis of these values demonstrated that the
means for replacer nos. 4% and #5 were both signifi-
cantly greater (P=<0.0l) than that for replacer no.
#1. In period 2,however, the nitrogen retention mean
for replacer no. an was not significantly greater
than that for replacer no. #5.

Further analysis of the data indicate that the
interaction between starters and the various replacers
was significant during period 2. These data demon-
strate that sub-groups A and B did not give consistant
results among the various replacers. This observed
difference was probably due to sampling errors caused
by small numbers of calves within each of the various
groups.

In the third digestion period, sub-group A re-
tention values for replacer no. 4% were significantly
greater (P=4D.Ol) than for replacer nos. #1 or #5.

The respective average nitrogen retention values of

-31-

sub-group A for replacer nos. #1, ##, and #5 were

#.26, 12.#8, and 0.50 grams per day. The average daily
retention values for the individual replacers in sub-
group B were #.78, 12.0#, and 8.3# grams per day.

The 12.0# grams per day retention for replacer no. ##
was significantly greater (R=(0.05) than the #.78 grams
per day for replacer no. #1, but was not significantly
greater when compared to replacer no. #5's 8.3# grams
per day. During the third period, there were much
greater differences between the sub-group average re-
tention values than during period 2. During period

2 the values were 5.57 grams per day for sub-group A
and 5.89 grams per day for sub-group B. In the third
period sub-group A held close to their previous average
retention with #.7# grams per day, while sub-group B
increased their retention to an average of 8.38 grams
per day.

All sub-groups increased their daily nitrogen
retention through all three periods with the exception
of sub-group A of replacer no. #5. The daily nitrogen
retention for this group decreased from #.67 grams per
day for period 1 to 2.8 grams for period 2, and only

0.50 grams per day during period 3. These values were

-32-

influenced by the difficulties encountered from the

effects of severe diarrhea in all # of the calves

assigned to replacer no. #5 during periods 2 and 3.
Apparent Dry Matter Digestibility

Dry matter digestibility data (Tables 8 and 9,
and Figure 2) indicated that there were no significant
differences between the replacers during period 1.
However, the average digestibility coefficient of 65%
for replacer no. #5 was considerably greater than
56.2% for replacer no. ## or 50.6% digestibility for
replacer no. #1.

During period 2, however, there was a definite
increase in digestibility of dry matter by the animals
comprising sub-group B. As compared to sub-group A,
average coefficients of sub-group B were 71.7% com-
pared to only #5.7% for sub-group A, (calves which
were not fed any dry feed). This difference was found
to be significant (P=<0.0l).

Calves in sub-group A had average dry matter
digestibility coefficients of 37, 56, and ##.2% for
replacer nos. #1, ##, and #5, respectively. The aver-
age coefficient of replacer no. ## was significantly

greater (R=<0.05) than for replacer no. #1, but was

-33-

not significantly greater than the average coefficient
of replacer no ##. Calves in sub-group B had respect-
ive digestibility coefficients of 70.1, 80.9, .aa 71.2%.
There were no differences among the replacers at the

5% level of significance.

In the third period there were even greater differ-
ences between the sub-groups' dry matter digestibility.
The calves fed the urea supplemented starter (sub-group
B) had a dry matter digestibility of 77.7%. In con-
trast, the digestibility coefficient mean for sub-
group A was only 36.7%. This difference was signi-
ficant (P=<0.0l). However, in period 3, there was
not a significant difference in dry matter digesti-
bility (P=<0.05) between the calves fed replacer nos.
#1, ##, or #5 in either of the sub-groups..

The composite data for the 3 periods demonstrates
that in all cases dry matter digestibility increased
with age of the calves allowed free access to liberal
amounts of starter and decreased with age for animals
that were continued on a gruel diet with no dry feeds
available.

Apparent Crude Protein Digestibility

The effect of the various replacers on crude

-3#-

protein digestibility was similiar to the results of
the nitrogen balance study. Namely in all three
trials there was a significant difference observed

in protein digestibility between the various replacers
(Table 10 and 11, and Figure 3).

In the first period the average protein digestibil-
ity coefficients were 63.1, 80.#, and 83.0% digesti-
bility for milk replacer nos. #1, ##, and #5 respect-
ively. At the 5% level of significance protein digesti-
bility values for replacer nos. ## and #5 were signifi-
cantly greater than the value for replacer no. #1.

During the second period there were no signifi—
cant increases in digestibility due to starter feeding.
However, in sub-group A the average digestibility co-
efficients were 67.6, 8#.3, and 78.6% for replacer
nos. #1, ##, and #5, respectively. The values for
replacer nos. ## and #5 were significantly greater
(P&<0.0l) than the value for replacer no. #1. Average
crude protein digestibility coefficients for sub-group
B in the second period were 72.9% for aplacer no. #1,
86.8% for no. ##, and 79.3% for replacer no. #5. The
apparent protein digestibility of replacer no. ## was

significantly greater (P=<b.01) than the value for re-

-35-

placer no. #1 and was greater than replacer no. #5
at the 5% level of significance. The average co-
efficient of protein digestibility for replacer no.
#5 was significantly greater (P=<0.05) than was the
average coefficient for replacer no. #1.

In period three the average protein digestibility
coefficient of 83.1% obtained for replacer no. ##,
sub-group A, was significantly greater (P=<0.05) than
the mean values for replacer nos. #1 or #5 which were
73.1 and 7#.#%, respectively. Considering sub-group
B, the 87.1% digestibility coefficient for replacer
no. ## and 80.3% digestibility value for replacer no.
#5 were both larger than the value of 71.8% for re-
placer no. #1 at the 5% level of significance.

The protein digestibility coefficients for each
replacer were relatively constant during all 3 col-
lection periods.

PART II --- BLOOD STUDIES

Tables summarizing the blood studies for the in-
dividual calves with accompanying graphs and the sta-
tistical analysis of the data are presented in Tables

12 to 15, and Figures # and 5.

-35-

Blood Urea Nitrogen
While there were some differences among calves
and replacer groups in blood urea nitrogen values
when the calves were assigned to the experiment, the
differences among replacer groups were not signifi-
cant (Tables 12 and 13, and Figure #).

lacer no. #1

‘J

At 12 days of age calves fed re:
averaged 9.05 mg.% blood urea nitrogen, as compared
to 9.91 mg.% for replacer n0. ##, and 11.31 mg.% for
replacer no. #5. These differences were not signifi-
cant.

The data from sample three (26 days of age) also
indicate no significant differences in the mean values.
The averages for the eight calves in each replacer
group were 7.76, 9.68, and 10.39 mg.% for replacer
nos. #1, ##, and #5, respectively. However, the mean
value for the urea supplemented replacer no. #5 ap-
proached significance (R=<0.05) in relation to the
value obtained for replacer no. #1. There were no
significant differences among replacers due to starter
feeding. However, the starter fed calves averaged
8.5 mg.%, as compared to 10.05 mg.% blood urea nitro-

gen for the calves on the gruel diet.

-37-

At #0 days of age the blood urea nitrogen aver--
ages for replacer nos. #1, ##, and #5 were 7.5#, 8.86,
and 8.71 mg.%, respectively. The differences among
groups were not significant. The mean blood urea
level for calves in sub-group A was 9.08 mg.% as c0m-
pared to 7.06 mg.% for sub-group B, again a non-signifi-
cant difference.

Blood Non-Protein Nitrogen

In general the data for blood NPN showed similiar
trends to that for blood urea nitrogen (Tables 1# and
15, and Figure 5). The values for the calves assigned
to replacer nos. #1, ##, and #5 were 25.9, 2#.5 and
28.1 mg.%, respectively. These differences among
groups were not significant.

At 12 days of age, the values for both replacer
nos. ## and #5 were not significantly larger (P=<©.O5)
than that for replacer no. #1. The actual values were
22.1, 2#.1, and 2#.2 mg.% for replacer nos. #1, ##, and
#5, respectively.

At 26 days of age, blood NPN values averaged
20.0, 21.1, and 25.96 mg.% for calves fed replacer
nos. #1, ##, and #5. The NPN level of calves fed re—

placer no. #5 was significantly higher (P=<D.05) than

-38-

values for the other two replacers. Calves in sub-
group A were found to have averages higher than the
calves of sub-group B, the averages being 23.5 mg.%
for A and 21.2 mg.% for sub-group B. Similarly to
the urea nitrogen studies, however, these differences
were not significant at the 5% level.

The calves on replacer no. #5 had the highest mean
NPN value at #0 days of age. Their mean NPN value
was 22.2 mg.%, as compared to 19.5 mg.%, and 20.2 mg.
% for replacer nos. #1, and ##, respectively. This
difference was not significant.(B=(0.05). The mean
NPN value for sub-group A was greater than for sub-
group B. However, this difference was very small,
averaging 20.7# mg.% for A, as compared to 20.53 mg.

% for sub-group B.

-39-

TABLE 6.
NITROGEN BALANCE
INDIVIDUAL CALF VALUFS

Grams nitrogen retained during 4—day collection period

REFLACER fi4l-A

 

 

calf no. period 1 period 2 period 5
445 ~15.74 ~2.28 7.62
465 17.04 41.57 ~6.88
456 —5.28 7.85 55.50
466 12.05 7.26 54.02
Av. 2.51 . 15.55 I7.02
HEPLACER #41-B -
calf no. period 1 period 2 period 5
427 ~55.79 -5.20 29.77
455 1.51 20.31 -5.14
455 - 2.69 15.67 52.15
465 —26.07 1.88 17.62
Av. —20.81 8.29 19.10
REPLACER #44—A
calf no. period 1 neriod 2 period 5
454 15.45 28.16 48.62
449 - .55 50.27 45.95
455 40.05 48.20 58.95
470 17.55 40.67 48.25
Av. 18.15 41.85 49.95
REPLACER #44—8
calf no. period 1 period 2 neriod 5
421 20.12 25.74 54.02
425 6.85 5.74 54.52
452 1.85 48.45 51.82
460 57.15 52.94 52.46
AV. .LE. :8 Q; .6". 43.16
~40-

TABLE 6 Continued
NITROGEN BALANCE
INDIVIDUAL CALF VALUES

Grams nitrogen retained during 4—day collection period

HEPL ACE-'1 #45—1‘.

calf no. period 1 period 2 period 5

 

444 11.71 6.22 —14.06
440 26.68 5.11 -59.7

476 22.88 22.94 41.57
478 50.08 12.20 20.42
AV. 22.84 11. 2 2.01

REPLACE-W #45—8

 

calf no. period 1 period 2 nerioi 5
422 51.15 15.48 59.86
432 5.29 15.5 14.14
458 9.45 26.8' 57.00
469 14.04 28.57 42.56
Av. 14.47 21.62 55.54

 

 

TABLE 7.

 

 

 

NI’T‘T‘ OFTEN BM A?”
STATIS ICAL ANALYSIS
PERIOD I
2
source :th 2}” n1.sq. F ratio
total 25 10,098.45
replacers 2 5, 9 2.29 1,966.16 6.696
within 21 6,166.16 295.65
PERIOD II

source d.f. {x2 111.3. . 1“. ratio
total 25 5,971.59
renlacors 2 1,638.(5 819.12 9.524
starters 1 11.69 11.69 .156
rep. x

starters 2 775.25 586.61 4.495
within 18 1,542.22 86.01

”37103 III

source 1.f‘. ix? m.s . F ratio
replacers 2 £190.225 2,595.11 6.858
starters 1 669.50 669.50 1.764
Pep. x

starters 2 1,521. 10 660. 55 1.740
within 18 6,851.75 579.5

~42u

TA: 6E 8
Ju" If. A”??? )I’}'_ F3 '" IE IL IT!
I“ DIVIJTT 1L CU F 17.413173
igestibility coefficients (percent)

REPL AC.“ 1741—11

 

 

 

 

 

 

 

calf no. Eexiod 1 period 2 Beriod 5
445 47.9 8.7 2.4
465 57.0 68.8 55.7
456 7.2 41.9 57.2
466 69. 2 28.5 25.2
Av. 52.3 57.0 35.:
REDLACFR #41—8
calf no. neriod11 period 2 reriod 5
427 16. 5.4 78.6
55 78.6 75.8 67.8
45 65.7 60.2 76.7
463 54.3 71.1 04.2
Av. 43.5 70.1 71.8
Ill-2:731: .47??? ,7}, '14- A
calf no. period 1 period 2 Period 5
454 85.7 57 45.7
449 27.1 54.4 22.4
455 42.2 60.8 45.0
470 32.5 51.0 27.3
Av. 46.5 56.0 54.1
I1EPJI 101-11 37,44—3
calf no. neriod 1 WGPIOW 5
m m J—-—-—————
421 42.5 78.2 91.4
25 80.6 82.8 86.4
52 78.5 87.5 80.5
460 62.5 75.5 73.6

_4:’~..

TMWJCB Cmfifinued
3?? NR“??? 3197RTTFIKITV

waIVI van can? VALV23
Digestibility coefficients (percent

22714022 #45—A
calf no. nertod 1 neviod 2 neviofl 5

444 57.4 54.
440 75.1 55
476 69.8

 

 

5
478 65.5 1.4.3 — 1.. 6:-
Av. 66.5 44.2 40.9
REPLACER #45-B
calf no. nerlod 1 neriod 2 rcriml 5
422 22.4 80.7 87.4
452 70.1 70.6 70.1
458 50.8 72.5 71.6
469 44.5 61.] 78.9

 

 

 

AV.

('7‘
C23
.
UT
q
p
o
'0
<1
\1
.
O

* value discarded

~44—

S OHPC e-

total
replacers
W I thi 11

S OJT‘C e

total
replacers
starters
rep. x
starters
within

30111799
————-———

total
replacers
starters
rep. X
starters
within

TABLE 9 .
JRY warms?

STR'PT77T7“I A‘

 

‘)_ 1L) I'Ut
PUJ.‘ I(JL) I
’7)
ngf. z.xo
O

3 8,465.79
2 811. 4:
1

7,622.55

 

 

PliEI 00 II
d.f. g x2
2. 9,192.95
2 948.72
1 4,819.50
2 . 75.87
'18 5,550. 84
ERIC!) III
d.f. 2f 2
25 11,841.51
2 165.62
1 10,081.90
2 250.3?
18 1,545.45

JTQFCMIFIIIMY
T'QVfi‘r-s
|).b-.-

\

474.56
4,819.50

56.94
186.16

.810
10,081.900

125.280
74.640

F ratio

1.4
U
1.4
n
D

g).

"11
"S
:17

(+-
[-1.
0

I0

in PC)
0 O
('13 tn
<0 OI

W.

1.109
125 . 070

1.678

J. "TABJJE 10
PROT FIN .JIG E." 7IBIIJIT '
IN DIVI JTIUJ CAI F VAI TTES

Digestibi1ity coefficients (percent)

calf no.

 

 

 

 

 

REPLACPR #44-A
oeriyil.

 

.. 46...

period 2

 

{EFT 115 ‘
calf no. BET 101 1
445 59.2 77.9
465 71.9 72.-
456 62:5 71.3
466 80.8 71.1
Av. 68.6 75.1
REPLACER #41—8
calf no. _Qeriod 1 Period 2 Epriod 5
427 41.1 72.9 74.0
455 84.3 75.5 62.8
455 66.0 69.4 76.1
465 58.6 75.9 74.5
Av. 57.6 72.9 71.8

oerioi
h—fi—

 

454 92.1 80.6 85.1
449 65.8 82.5 79.7
455 76.5 89.0 85.8
470 75.0 5.4 85.7
v. 77.5 84.5 85.1
REPLKCER #44~B
calf no.— period 1 period 2 Eeriod 5
421 69.5 81.6 92.2
425 88.8 87.5 87. 2
452 88.5 90.1 84.4
460 87.0 88.2 84.5
Av. 55.4 86.8 87.I

TABLE 10 Continued
PROTEIN DIGESTIBILITY
TNDIVIJUXL CALF VALUES

Digestibility coef icients (percent)

 

 

 

 

 

REFLACER #45—A

calf no. Eprlod 1 . period 2 period 5

444 75.5 80.4 81.5

440 85.0 80.1 71.8

476 88.6 84.2 86.4

478 87.2 69.5 57.7

Av. 84.0 78.6 74.4
REPLACE: #45-8

calf no. nerioi 1 Eeriod 2 neriod 5

422 89.9 85.8 86.4

452 85.7 69.0 69.0

458 79.8 82.0 82.1

469 74.9 80.5 85.7

Av. 82.0 79.5 80.5

S 01.) 1"? 9

total

replacers

within

TAELE 11.

PROTEIN DTGFSEIBILITY

222109 I

d.f. érxg

3 4,274.07
2 1,863 79

21 2,905. 28

3

‘u
\\

PERIOD II

 

source r1.f. gx?’
total 25 1,955.56
replacer 2 1 ,144.8;
starter 1 49.02
rep. x
start er 2 22 .07
within 18 717.5
PERIOD III
(3
source §§§;__
total 25 1,614.45
replacer 2 647.42
starter 1 49.60
rep. x
starter 2 56.72
within 18 860.69

-48~

IST 1 C 1L AN AT.

YSIS

954. 40
158.55

LI. 8‘) .

2.44
49.02

Ind

11.05

'2" Q
L’u . 'J

5.71
49.60

28.56
7.32

 

F rptio

 

‘1.:z/61
1“)" (I

an
09'

F T8t10

(‘\

Hcfi
Q I

r) ‘3
'51 .‘ .
\1 (I)

O

n
(O
Cfl

calf no!
445

465
4.76
460
Av.

ij‘ r10.

427
455

455

flI’T'Z
'71'\)\‘

Av.

091f no.

454
449
455
470
Av.

‘
08: T10.
W
91
~.L
425

452
460

Av.

("111711 E 12
19911TWn
I‘I DT‘JI DTIAJI C111 ‘T I?

.' 1’;
If i? . ‘Ila

VALUE?

REPLACER #4l-A

'1ij“ (3. , O 'z
191. S4Kflc 2

13‘;]i"71 e L)

 

 

10.45 5 20 8.15
15.75 15.25 10.20
12.85 5.85 10.2
19.95 15.20 7.45
14.65 9.52

 

 

6.15 7 75 3.50
9. 35 12.20 5.20
11.:15 '7 20 9.00
17.99 7.75 9.49
11226 '9775 6.55

REPLJ43?R
abmnle 1

#44—4

8 ‘41 1 1) -1- C 2 3 #111111 e 3

 

 

9.25 10. 70 8.45
4.55 7. 90 8.00
11.90 8.85 12.
7.75 17.10 8.29
8.32 m 9.00

 

 

 

REPLACE? #44-8
Sump1e 1 99mn1€ 2 sunnlé 5
19.80 7.50 8.70
6.70 6.00 11.10
6.15 12.15 8.50
9.50 9.10 11.50
10.54 8.69 9.85

821(k)]. C 4

"' Cl

Lt.k1

6.60
10.75
6.60
7.55

savTflws 4

6.40
10.75
8.55
16.00
10.45

O
4
H
4)

.0
)QCn
nincno

4-1
01—41191
no
f)?!

 

‘1
o

03
(D

calf no.

 

444
449

4'7»
‘210

478
Av.

Cu1f no.

m6fi33
()QAOOD

wa4>¢~$
(T:

‘V

t’1

M30 fl

 

R"nLP.3:1{ 3145-11
Sqmnle 1 Szrnp1e 2 samnle 5
8.85 8.95 14.5-
0.30 6.80 13.00
13.2 13.50 11.45
17.10 10.25 7.90

12.24

5.55
10.45
11.85
15.5?

11.1.4-

11.50

)

O
t
k.

0
:1”. CH CH H

mcnm)m
:nCDm

 

(D
O

1'"
C-l

snmfile 4

15.9
6.70
9.19

6.80
9.45

S :3 vmv1€ 4
W

C
3T

 

source d.P
total 23
sampling 2
\‘v'itZIin 21
source d.f.
total 23
replacers 2
within 21
source g.f.
total 23
replacers 2
starters 1
rep. x
starters 2
within 18
source i.f.
total 23.
replacers 2
starters 1
rep. x
starters 2
within 18

RTIS7ICKL

TABLE 13.

4

BLC

O

3 HT“. ;.: ’1
AN ALYS IS

8 ALIFL E I

5X2 1‘5. 8 .
543.42

49.74 24.37

493.68 23.51

SAMPLE II

 

 

 

{x2 1'. so.
393.72
20.74 10.37
372.93 17.76
SAMPLE III
25x2 M. sq.
162.40
29.60 14.80
14.50 14.5
10.87 5.43
107.43 5.97
SANPLE IV
5x2 __ N. so.
258.81
8.26 4.13
12.12 12.12
12.26 6.13
226.17 12.57

—51—

F ratio

1.058

F ratio

.584

F ratio

2.479
2. 429

.910

.329
.964

.488

031? no.

443
405
456
466
AV.

calf no.

(31"?
.L,’

33

AC"!
‘r0./x_)

463
Av.

091? no.

434
449
455
470
Av.

7')
m
FJ
w

 

42
42.
452
460
AV.

1 -
J NrN

INDIVIDUAL C .' RF VALUE?

 

 

.- ,4
‘Vrr. [’0
VEPTACER #41—A

samn1e 1 sqmwle 2 s-mvle 3
._ 4.. L .9
22.7 18.7 20.0
50.4 p'3.5 :3";.5
91.9 13.? 2?.

n
an-.. ’9.8 34.9
”5.0 25.05 20.5

 

'7’?
tr.7
n
(35.7
f5
24.0
23.?
(\f‘ “
(4on

” SHQD3€ 3

21.9 21.1
25.2 15.3
12.8 21.5
22.6 13.9
22.12 19.45

 

OJ L J _b

abuts-QC)"

‘3

JCfll-JQF-J
o

 

M
C
O

as

 

?1.1 90.6
21.1 17.7
q r", H (‘II‘
L I . I (4;). (.I
'IC '7 “(V n
\,'--. 1., l-L'I.‘J
0” q 0“
Cut}. (.1 L.‘
I. {TUNE ié‘I4AT~B

fiamnle 2 Samrle 3

 

 

O
0103me
O
(Q

‘~
t

3 so u to
.44>C>o
O

 

 

m
s
.p.
D
(n

U}
F
Q
m
.5

I
._,.

 

0
‘0 O F’ [‘0
Q

H‘DFJH
—o»aqca
O

 

‘.J
<1

0

'1)

 

sarrmle 4
.-——-h——

 

TABLE 14 Continued
BLOOD NPN
II‘JDIVI DUAL CALF VfiLUEf‘)
MEL. 3‘;

REPLACE 42145—11
1 smmle 2 sovmle 3 samr‘ale 4

50
Q3
3
:5
1.1
(b

Calf no.

 

 

 

 

444 23.8 21.4 24.9 23.2
440 20.9 18.7 20.3 10.1
476 37.0 27.0 38.2 29.4
478 27.0 29.4 29.4 24.7
Av. 27.175 24. 25 28.2 23.75
I? E21140??? #45-2
calf no. Sumnle 1 ssmn1e 2 sth19 3 samnle 4
422 21.7 24.1 --- 18.7
432 42.3 20.9 26.0 18.5
458 24.8 27.0 22.6 26.5
469 26.5 25.9 22.6 20.4
Av. 28.9 5 94. 4'75 2W3 “c.'1".'025

30 {1‘0 e

total
8 ampl ing
within

S O‘JI‘C 8

total
rep1scers
within

8 011110 e

total
replacers
starters
rep. x

starters

within

8 0111106

total
replacers
starters
rep. X

starters 2

within

 

 

 

TABLE 15.

757 an 17-11?
IDA-ILA .' ) 1‘11” JV

 

 

 

 

STATISTICAL
3111‘211’1111'? I
d. f. 2x2
23 982.16
2 57.77
21 924.39
SAMPLE II
1.r. .5x2
23 551.66
-2 24.08
21 527.58
SAMPLE III
1. 1‘. 2x2
25 534.06
2 160.49
1 31.28
2 14.42
18 327.96
SANPLE IV
d.f. 233
25 457.12
2 30.7
1 .2
7 34.15
18 371.92

ANALYSIS

 

L. 8.. F ratio

28.89 .656

44.02

M. 39. F ratio

12.04 .479

25.12

M. sq. F ratio

80.20 4.402

31.28 1.717
7.2 .396

18.22

F. sg. F ratio
15.39 .745.

.2‘ .0013

17.08 .827
20.66

en Retained Per Day

3"
Q

Grams Nitro;

 

Sub-group A

 

 

 

Sub-group B ___________
Raglager No.
44-A
12.0 -— /
‘1—44—8
/
/
/
/
l0.0_. /
/
/
/
/ r_
800 " / /4'—40 B
/ /
/
/// /
/
/
/// __,.//
744’7”# .4- 91-13
/
4‘0 ’ / 41-11
/
/
—.____ ./
2.o- ‘‘‘‘‘ /
+5-&
000 L 4
15-19 29-33 43-47

A30 of Calf (Days)
Figure 1
AVERAGE NITROGEN BALANCE VAUJES

~55-

 

Sub-gr cup A

 

 

 

&mnflmq1B ——————w—————
90 r“
me 112222.19:

80 — //"

75 / / x/l—zw-B

(D / / /

3 / // _, ,,,,, *4—11-8

£§70'_ /‘// /;/”'

‘~.°\ / /// /

V ” / /

m / /

3 /

,__4

:1 60 "- / //

I: /

‘3?

9’0 /

S /

$.50

(D

+_)

.3

>1

5E3 40 >— 5‘14;

4-A
l-A

30 l I
15-19 29-33 43-47

age of Calf (Days)

Figure 2

AVERAGE APPARLAT DRY MATTER DIGLQTIBILITY VAUJLS

~3

Sub-group A

 

Sub-graip B _________ '—
90
ieplacer ho.

 

/ /’M4-B

Protein Digestibility (% Retained)

 

 

50 L l
15-19 29-33 43-47

Age of Calf (Days)
Figure 2
AVERAGE APPBRLNT PROTEIN DIGLSTIBIL'TY VALUES

.57.

Sub-group A

 

amfixwpfl _"____"____
13

12‘ ‘

Repiacer No.
11~

p
O
l

 

mg Z Blood Urea
¢>

CD
I

 

 

5L 1 I I
.2 12 26 40
Age of Calf (Days)
Figure 4

AVERAGE BLOODIJRLA VADJES

-58~

en (m5 2)

‘ -
0

Blood Non-Protein Nitro:

 

Sub-group a

Sub-group B ————————
30.0 _

 

27.5
Replacer No.

 

 

5 ‘A

4l-A

15.0 , J
12 26 4o

 

If)

age of Calf (Days)
Figure 5
AVERAGE BLOOD RON-PROTEIN NITROGLN VALUES

[—

DISCUSSION

Data for the urea supplemented milk replacer
no. #5, during the first digestion period, indicated
that the 15 to 19 day old calf utilized the non-pro-—
tein nitrogen source, urea. The nitrogen balance,
apparent protein digestibility, and apparent dry
matter digestibility average values indicated that
the young calf can utilize urea equally as well as
the conventional milk protein diets as studied in
this trial.

However, the results for the two succeeding di-
gestion studies were not as conclusive. In digestion
periods 2 and 3, the calves that were fed the urea
replacer, no. #5, in sub-group B, (calves allowed
free access to calf starter) significantly exceeded
the mean nitrogen balance for the control group.
During the second digestion study (calves 29 to 33
days of age), the relative increase of replacer no.
#5 over no. #1, was 70.53 as large as the increase
of no. an over no. #1. The actual values for the 3
replacer groups during period 2 were for no. #1, 2.07
grams/day, no. ##, 6.81 grams/day, and for no. #5,

5.Hl grams/day nitrogen retention. In the third

-60...

digestion period in sub-group B, the calves allowed
urea starter as a dry feed (the urea supplemented
calves, replacer no. #5) account for M9% of the in-
crease in nitrogen retention of replacer no. 4% over
no. #1. The actual retention values for the replacer
groups were for no. 41, H.78 grams per day, no. nu,
12.0% grams per day, and for no. #5, 8.3” grams per
day.

iany workers have pointed out that ration char-
acteristics greatly influence urea utilization.
Lengemann and Allen (1955) reported that amounts of
dry feeds and amounts and kinds of bacteria ingested
effected the deve10pment of a functioning rumen.
Flatt at; El; (1956) reported that the rumen mucosa
of calves fed dry feeds developed faster than those
kept on milk diets. Brownies (1956) reported that
nutritive values of the dry feeds also influenced
development of a functionally mature rumen.

The results of this study also indicated in-
creased utilization when dry feeds were included in
the young calf's diet. More favorable results were
obtained when the combination of gruel and the urea

supplemented calf starter was offered ad libitum

-61-

compared to gruel feeding alone. The relative differ-
ences in nitrogen retention between the calves fed

the starter and those fed only gruel increased with
age, indicating that under the conditions of this
study, including dry feed in the diet increased the
relative nitrogen balance and urea utilization by the
calves. The calves receiving only milk replacer no.
#5, (the urea supplemented replacer), as a gruel with
no dry feed offered, were afflicted with severe diarrhea
which may have influenced their respective nitrogen
balance values.

It is apparent that the very young calf is able
to utilize urea nitrogen at all ages studied. The
results of the first digestion period indicate that
when the calf is weaned from milk at an early age it
becomes able to utilize non-protein nitrogen by 15
days of age.

Critical analysis of the apparent protein digesti-
bility coefficient values also indicated early utili-
zation of urea. The relative results were very similar
to those obtained in the nitrogen balance study.

During the first digestion period the calves on

replacer no. 45 digested a higher percentage of their

-62..

nitrogen intake than those on the conventional protein
supplemented replacer no. an or the low protein basal
group fed replacer no. #1.

In the second period the apparent protein digesti-
bility values for these calves were 67.6% and 72.9%
for 41 A and B, 84.3% and 86.8% for an A and B, and
78.6% and 79.3% for #5 A and B, respectively. Compar-
ing the relative increase in protein digestibility of
the calves fed replacer no. #4 over no. #1 to those
fed replacer no. #5 over no. 41, the increase for
replacer no. #5 in sub-group A was 65.2% as great as
that for those fed replacer no. #4. The relative
increase of replacer no. #5 over no. 41 for sub-group
B was 43.0%. These values for calves fed replacer no.
#5 were significantly greater (P=<0.05) than the ap-
parent protein digestibility of the calves fed the
basal diet, replacer no. #1. The mean value for sub-
group B, (replacer no. #5) during the third period was
55.5% as great as for no. 8%. The actual values for
sub-group B were 71.8%, 87.1%, and 80.3%, respectively,
for replacer nos. #1, 4%, and #5. However, in sub-
group A, during period three, the increase over the

basal group was slight, due in part to errors from

-53.

unnatural responses by the animals.

The similarity of the results from the nitrogen
balance and nitrogen digestibility portions of the
study supports the conclusions derived from the early
nitrogen utilization.

The mean coefficients for apparent dry matter
digestibility were much more stable between the re-
placers and among the sub-groups than were the coef-
ficients for either nitrogen balance or apparent pro—
tein digestibility. The largest and most significant
differences were between the sub-groups, that is,
calves receiving the starter gave significantly
greater retention values than the gruel fed animals.
This condition is at least partially explained by the
difference in fecal characteristics of the sub-groups.
The calves assigned to sub-group A produced consider-
ably more fluid excreta than the calves in sub-group
B which had the dry feed.

Higher levels of protein in the supplemented
replacer nos. ##, and 45, as shown in the second and
third periods, both gave significantly greater (B=<0.05)
dry matter digestibility values than that for replacer
no. 41.

-6h-

In all cases there is a positive correlation_
between apparent dry matter digestibility and age.

The blood data produced few statistical conclusions.
In general, the values for blood urea and non-protein
nitrogen reduced with increasing age of the calves.
The most notable exception to this generalization was
for sub-group A fed replacer no. #5 whose values for
urea nitrogen and NPN held quite steady during the
second and third periods.

The mean values for both blood urea and non-pro-
tein nitrogen were within the averages quoted by
Handbook 9: Biological Data (1956). In the last three
samples taken after replacer feeding was commenced,
the calves fed the urea supplemented replacer, no. 45,
produced higher blood urea and non-protein nitrogen
values than did either the calves fed replacer no. #1,
the basal group, or those fed replacer no. an, the
conventionally supplemented group. In all samples
studied, the mean for sub-group A of replacer no. #5
calves was higher than sub-group B. In sample three
the non-protein nitrogen value for replacer no. #5,
sub-group A was significantly higher (2:40.05) than

the averages for replacer nos. #1 or #5.

-65-

It can be concluded that the feeding of urea to
the young calf tends to raise the blood levels of urea
nitrogen and non-protein nitrogen. However, since
with only the one exception, these values were not
significantly higher, it can be concluded that the
calf has the ability to utilize at least a portion of

its nitrogen from a urea source.

~66-

SUM IARY

A study was carried out to determine the ability
of young calves to utilize milk replacers supplemented
with urea. Twenty-four male Holstein calves were
assigned to three experimental milk replacer diets.

The basal diet was a 10% crude protein replacer
designated as no. 41. {ilk replacer no. MM was a 18%
protein replacer supplemented with conventional milk
proteins. Milk replacer no. #5 was an 18% protein

urea supplemented ration (urea 46.9% of the total
protein). The calves were weaned from milk at ten

days of age. At twenty days, the eight calves assigned
to each replacer group were divided into two sub-groups,
A and B, of four calves each. Sub-group A were fed

an increasing amount of milk replacer as a gruel with
no dry feed offered. In contrast sub-group B calves
were fed a decreasing amount of replacer but had free
access to an urea supplemented calf starter (urea H9.h%
of the total protein). Neither group were allowed hay
during any period in the study. Digestion studies

were conducted on all calves at 15, 29, and #3 days

or age.

-67-

The data assembled from the digestion studies in—
dicated that the young calf could utilize urea as a
dietary source of protein at 15 to 19 days of age.
Blood levels of urea nitrogen and non-protein nitrogen
were found to consistently decrease with age. The
calves receiving the urea supplemented milk replacer
had higher blood values for urea nitrogen and non-pro-
tein nitrogen than did calves in either of the other
two experimental rations.

The results of the present study are in agreement
with earlier studies reported. It appears that when
the young calf is weaned at a very early age, it
develops the ability to utilize a non-protein nitrogen
source by the time it reaches three weeks of age. How-
ever, it appears that several dietary and managerial
factors must be considered in determining the future
use of urea as a protein substitute in the diets of

the very young calf.

-68-

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“_

9; Research gg Urea and Ruminant Nutrition. A
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-70-

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u.

 

 

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