W681?

                   

lllllllllllllllllllllllllllllllllll'llllllllll

31293 00897 8540

This is to certify that the

thesis entitled

The Effect of Maturity on Yield, Quality, and Protein
Degradability for Three Temperate Forage Legumes
(Medicago sativa L., Trifolium pratense L., and
Lotus corniculatus, L.)

 

 

 

presented by

Jeremias Rodriguez

has been accepted towards fulfillment
of the requirements for

Masters Crop and Soil Sciences

degree in

 

 

(aflw 5 Watt/by

Major professor

 

Dan: March 29, 1993

 

0-7639 MS U is an Affirmative Action/Equal Opportunity Institution

 

LIBRARY
Mlchlgan State
Unlverslty ,

 

 

L‘

 

PLACE‘IN RETURN BOX to remove this checkout from your record.
TO AVOID FINES return on or before date due.

  

DATE DUE DATE DUE DATE DUE

 

 
 

til! 1 5 1994

r";

jig— I
ll %

MSU le An Affirmetlve Action/Equal Opportunity Inuitutlon
chG-DJ

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

___.,_—. __.._____—

 

THE EFFECT OF MATURITY ON FORAGE YIELD, QUALITY, AND
PROTEIN DEGRADABILITY FOR THREE TEMPERATE FORAGE

LEGUMES W m L., Trifoligm m L., and
Latin mm L.)

By

Jeremias Rodriguez

A THESIS

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

MASTER OF SCIENCE

Department of Crop and Soil Sciences

1993

ABSTRACT

THE EFFECT OF MATURITY ON FORAGE YIELD, QUALITY, AND
PROTEIN DEGRADABILITY FOR THREE TEMPERATE FORAGE
LEGUMES (Mediggo sativa L. , Trifolium pratense L., and
Lotus gorniculatus L.)

By

Jeremias Rodriguez

Traditionally, forage legumes are harvested according to a calendar date rather
than at a specific morphological stage of development. A randomized complete block
split-plot experiment was used to evaluate the effect of plant maturity on dry matter
yield, forage quality, and i_n §i_tu protein degradability of alfalfa, red clover, and
birdsfoot trefoil at three cutting dates over five harvest cycles in a two-year study.
Legume maturity was quantified using mean stage by weight (MSW). Dry matter
yield, neutral detergent fiber, acid detergent fiber, and escape protein (EP)
concentrations increased with advancing maturity as evaluated using MSW, while no
regular pattern was observed for crude protein. All three legumes had equal EP
concentrations in three harvest cycles. In one harvest cycle, alfalfa and trefoil had
higher EP than did red clover. These legumes are potential sources of EP for
ruminants, and MSW is a useful tool for quantifying yield and quality of red clover

and trefoil.

To my parents, Simeona and Paulino,
I am endlessly grateful to both of you for
everything you have done for me through
my whole life. I love you, sefiores.

To my wife, Rebeca,
With you the life is much easier. Thanks
for being with me during these last 3 years.

To my brothers and sisters,

Because you are the inspiration for continuing
working for a better tomorrow.

ii

ACKNOWLEDGEMENTS

I extend my sincere appreciation to my major professor, Dr. Oran B. Hesterman,
who has guided me through my Master’s studies at MSU. I want to thank Dr.
Hesterman because from him I have learned how to be a better professional and a
researcher in the forage field. Also, I am grateful to Dr. Hesterman for his valuable
help in completing this thesis, which is the corner stone of my career. I am also want
to thank to Dr. Wally Moline, Dr. Dale Harpstead, and Dr. Steve Rust for serving on
my guidance committee.

Special thanks to Dr. Kim Cassida for her help with the statistics and corrections
for this thesis. I am also grateful to Dr. Cassida for her constructive suggestions during
the thesis elaboration. Also, special thanks to Joe Paling, M.S. for showing me how to
use the sickle-bar mower for harvesting forages, and how to handle all lab equipment for
herbage quality analysis. Furthermore, I would like to thank Stacey Campbell and Jason
Neumann, for their help on the herbage quality work in the lab. I also want to thank
Eric Spandl, Peter Tiffm, and Dr. Glen Harris for supporting me during these two and
a half years.

I would also like to thank the Instituto Superior de Agricultura (ISA) and the

Agency for International Development (AID) for their sponsorship.

iii

PREFACE

This thesis is written as a manuscript in the style required for publication in the

Agronomy Journal.

iv

TABLE OF CONTENTS

PAGE

LIST OF TABLES vi

LIST OF FIGURES viii
INTRODUCTION 1

MATERIALS AND METHODS 12
RESULTS AND DISCUSSION 18
CONCLUSIONS AND RECOMMENDATIONS 30
REFERENCES 43

APPENDIX 50

TABLE

A1

LIST OF TABLES

TITLE

Air temperature and precipitation in spring
and summer of 1991 and 1992 at the

Agronomy Farm at Michigan State University,

East Lansing, MI.

Effect of cutting date on dry matter (DM)
yield, neutral detergent fiber (NDF), acid
detergent fiber (ADF), crude protein (CP),
and escape protein (EP) concentrations of
alfalfa, red clover, and birdsfoot trefoil
for five harvest cycles in 1991 and 1992.

Effect of forage species on dry matter (DM)
yield, neutral detergent fiber (NDF), acid
detergent fiber (ADF), crude protein (CP),
and escape protein (EP) concentrations of
alfalfa, red clover, and birdsfoot trefoil

for five harvest cycles in 1991 and 1992.

Interaction between species and cutting date
for dry matter (DM) yield, neutral detergent
fiber (NDF), acid detergent fiber (ADF),
crude protein (CP), and escape protein (EP)
concentrations of alfalfa, red clover, and
birdsfoot trefoil for five harvest cycles

in 1991 and 1992.

Growing degree days (GDD) for alfalfa, red
red clover, and birdsfoot trefoil at early-,

medium-, and late-cutting date during five
harvest cycles in 1991 and 1992.

vi

PAGE

33

34

36

38

50

A3

A4

A6

A7

Mean stage by weight (MSW) for alfalfa, red
clover, and birdsfoot trefoil at early-, medium-,
and late-cutting date for five harvest cycles

in 1991 and 1992.

Linear and quadratic regression equations and

r2 values of dry matter (DM) yield, neutral
detergent fiber (NDF), acid detergent fiber (ADF),
crude protein (CP), and escape protein (EP)
concentrations of alfalfa, red clover, and

birdsfoot trefoil regressed on growing degree

days (GDD) for five harvest cycles in 1991 and
1992.

Linear and quadratic regression equations and

r2 values of dry matter O)M) yield, neutral
detergent fiber (NDF), acid detergent fiber
(ADF), crude protein (CP), and escape protein
(EP) concentrations of alfalfa, red clover, and
birdsfoot trefoil regressed on mean stage by
weight (MSW) for five harvest cycles in 1991 and
1992.

Table of means of dry matter (DM) yield,
neutral detergent fiber (NDF), acid detergent
fiber (ADF), crude protein (CP), and escape
protein (EP) concentrations of alfalfa, red
clover, and birdsfoot trefoil at early-, medium,
and late-cutting date for five harvest cycles

in 1991 and 1992.

Table of means of m si_tu dry matter digestibility
(ISDMD) of alfalfa, red clover, and birdsfoot
trefoil at early-, medium-, and late-cutting date
for five harvest cycles in 1991 and 1992.

Correlation coefficients of dry matter (DM) yield,
neutral detergent fiber (NDF), acid detergent fiber
(ADP), crude protein (CP), and escape protein (EP)
concentrations of alfalfa, red clover, and birdsfoot
trefoil at five harvest cycles in 1991 and 1992.

vii

51

52

54

55

57

58

A8

Dry matter (DM) yield and crude protein (CP) yield
total over a two-year study for three temperate
legume species (alfalfa, red clover, and birdsfoot
trefoil) at three cutting dates (early-, medium-, and
late-).

viii

59

FIGURE

LIST OF FIGURES

TITLE

Dry matter (DM) yield of red clover and birdsfoot
trefoil regressed on mean stage by weight (MSW).

Neutral detergent fiber (NDF) of alfalfa, red clover,
and birdsfoot trefoil and acid detergent fiber (ADF)
concentrations of red clover and birdsfoot trefoil
regressed on mean stage by weight (MSW).

Escape protein (EP) concentration of red clover
regressed on mean stage by weight (MSW).

PAGE

40

41

42

INTRODUCTION

Forage legumes are an important source of nutrients for feeding ruminant
livestock because animals can efficiently convert these high-quality fibrous materials
into milk and meat. In many countries in which cattle production is important, forage
legumes are valuable because they produce high dry matter yields.

More than 50 percent of the world’s cattle population resides in the Tropics
and Subtropics; however, these areas only produce 20 to 30 percent of the world
supply of meat and milk (Rotar and Krestchmer, 1985). This is partly because
forages are not efficiently managed in tropical areas. In contrast, in the temperate
zones of North America and Europe, where the dairy enterprise is important, forages
are intensively managed and animal rations are often based upon the use of legumes.

Alfalfa (Medicago sati_va L.) and red clover (Trifolium p_r_at_en_se L.) are the
primary forage legumes used for animal feeds in the northern and northeastern parts
of the USA (Smith, 1962; Barnes and Sheaffer, 1985; Taylor, 1985; MacGraw and
Marten, 1986). Birdsfoot trefoil (_Lo_tus corniculatus L.) has become a very important
forage crop in the last several years in the northwestern and northcentral parts of the

USA (Grant and Marten, 1985).

2
In recent years in the USA, considerable emphasis has been given to

harvesting forage legumes at proper stages of maturity. Traditionally, legumes were
harvested according to a calendar date instead of a specific plant morphological stage
of development. This kind of legume management produced high herbage yield, but a
lower protein concentration than considered optimum (Smith, 1962; Van Soest et al.,
1978).

Forage quality and yield are influenced both by harvest schedule and by the
plant’s morphological stages of development at harvest. Differences in dry matter
(DM) yield and crude protein (CP) concentration exist among different plant species
harvested on differing schedules (Van Soest et al. , 1978). Additionally, stages of
plant maturity can influence protein degradability (Brink and Marten, 1970 and 1983;
Smith, 1972; Kalu and Fick, 1981 and 1983; Fick and Jansen, 1990; Olhson and
Wedin, 1989; Sanderson et al., 1989).

At more advanced stages of maturity, forage legumes decrease in CF
concentration and increase in neutral detergent fiber (N DF), acid detergent fiber
(ADF), and lignin concentrations. Herbage dry matter yield also increases as cell-
wall components (cellulose, hemicellulose, and lignin) increase with maturity (Van
Soest, 1967). Rumen escape protein concentration in legumes also may increase with
the increase in herbage cell-wall components as plants mature (Griffin et al. , 1991).

To obtain maximum nutritive value from alfalfa, red clover, and birdsfoot
trefoil, a sound management approach must be used to relate plant maturity stage at
harvest to herbage yield, quality, and protein degradability (Marten, 1970; Van Soest,

1978; Sanderson and Wedin, 1989). The experiment described in this thesis provides

3

information critical to developing a more efficient approach to harvest management of

three temperate forage legume species.

Impact of stages of maturity and harvest schedule on forage yield of alfalfa, red
clover, and birdsfoot trefoil

In the northern of the USA, researchers have recommended a three-cut system
for harvesting legumes (Smith, 1962 and 1965; Marten et al. 1988) because three
cuttings before 1 September gave higher seasonal herbage yields than cutting at more
or less frequent intervals. In contrast to the three cut-system recommended by Smith,
Tesar (1970) reported that a system with four harvests, the first by late May to early
June (bud stage), the second by 5 to 10 July (first flower), the third by 20 to 25
August (first flower), and the fourth by 15 to 30 October yielded 10 percent more
herbage than the standard three-cut system (1 June, 15 July, and 15 August). Brink
and Marten (1983) showed results similar to those of Tesar when using a four-cut
system with the last cut by 1 October. Other researchers have also related
morphological stages of legume plant development to total herbage yield and protein
content and digestibility (Brink and Marten, 1983; Smith, 1972; Kalu and Pick, 1982
and 1983; Pick and Jason, 1989; Olhsson and Wedin, 1989; Sanderson and Wedin,
1989). Management systems for legumes based on harvest schedule and plant
morphological stages of development may result in both high dry matter yield and
high nutrient content (protein, minerals, and nonstructural carbohydrates) with plant

maturity (Sheaffer et al., 1988).

4

Legume dry matter yields increase from vegetative to reproductive stages of
development of the plant (Kilcher and Heinrichs, 1974). Dry matter yield of stems
increases at a constant rate throughout plant development from vegetative to
reproductive stages. However, the dry matter yield of leaves increases at a constant
rate only during vegetative stages; as plants mature, leaf dry matter increases at a
decreasing rate (Kalu and Pick, 1983). Kalu and Fick (1983) found that alfalfa had a
higher yield when harvested at later stages of development compared to earlier stages
of development. They used a IO-stage numerical system (3 vegetative, 2 bud, 2
flower, and 3 seed-pod stages) to quantify phenological development based on a mean
stage by weight system. Similar results were reported by Latheef et al. (1988).

On many soils, at later stages of plant maturity, birdsfoot trefoil produces less
total DM yield than is produced either by alfalfa or red clover (Marten and Jordan,
1979). Nevertheless, dry matter yield of birdsfoot trefoil increases with advancing

maturity similarly to the other two legume species (MacGraw and Marten, 1986).

Impact of stage of maturity and harvest schedule on forage quality of alfalfa, red
clover, and birdsfoot trefoil

Forage quality refers to the nutritive value of the plant material and is
commonly determined by the concentration of acid detergent fiber (ADF), neutral
detergent fiber (NDF), and crude protein (CP) in the herbage. Typically, forage
quality declines as plants progress from vegetative to reproductive stages of
development (Smith, 1972). As plants mature, major changes occur in the quality of

plant stems (Albrecht et al. , 1987), while leaves change little in quality with maturity

5
(Buxton et al. , 1985). Total herbage quality declines with maturity due to the

decrease in leaf: stem ratio (Buxton and Horstein, 1986). Highest concentrations of
herbage nutrients (crude protein and soluble carbohydrates) are usually obtained with

forage harvested at immature stages of development (Brink and Marten, 1983).

Components of forage quality
Neutral detergent fiber

The term NDF is synonymous with plant cell—wall components, which are
cellulose, hemicellulose, and lignin (Van Soest and Wine, 1967). Neutral detergent
fiber is measured by an extraction procedure with a neutral-pH detergent solution
(Goering and Van Soest, 1970) and is the measure of plant structural components
most related to forage intake in animals. As NDF concentration of a forage
increases, intake potential decreases (Van Soest, 1982).

Sanderson and Wedin (1989) reported a quadratic increase in alfalfa stem and
total plant herbage N DF concentration with advanced plant maturity. Sanderson and
Wedin stated that the increase in NDF concentration was due to a decrease in the
leaf: stem ratio. Thus, it appears that stems contain higher NDF concentration than
leaves. According to Sanderson and Wedin (1989), 97 percent of the variation in
stem NDF concentration was accounted for by the variation in phenological stages of
development as measured by MSW. They also reported that 98 percent of the
variation in herbage NDF concentration was accounted for by the variation in

phenological stages of development as measured by MSW.

6
Sanderson and Wedin (1989) also reported a linear increase in NDF

concentration of red clover stems and herbage with advanced phenological maturity.
They stated that phenological stage accounted for 85 and 94 percent of the variation in
red clover stem and herbage NDF concentrations, respectively. Birdsfoot trefoil
herbage also increases in N DF concentration as plants mature (Buxton and Brasche,
1991). At later stages of maturity, NDF concentration in birdsfoot trefoil has been
reported to be lower than at similar maturity stages in alfalfa (Buxton and Brasche,

1991).

Acid detergent fiber

Acid detergent fiber is the plant cell-wall component related to herbage
digestibility, and is composed of cellulose and lignin (Van Soest, 1965). The
cellulose component of ADF is a potential source of carbohydrate for rumen
microbes. Lignin is not degraded by rumen microbes and provides no nutrients,
while also decreasing the degradability of cellulose. Lower ADF concentration in
herbage indicates higher herbage digestibility (Van Soest, 1982). An extraction
procedure with an acid-pH detergent solution is used to determine ADF concentration
(Goering and Van Soest, 1970).

As legume herbage matures, the ADF fraction of plant cell-walls increases
(Sanderson and Wedin, 1989). The proportion of ADF composed of lignin also
increases with advancing maturity, reducing the proportion of cellulose, and therefore,

decreasing forage digestibility (Akin, 1989). Lignification of plant cell-walls is a

7

major factor limiting legume digestibility. As plants mature, core lignin increases,
reducing forage digestibility (Akin, 1989; Jung, 1989).

Kalu and Pick (1983) found that ADF concentration of alfalfa leaves remained
unchanged (range of 13 to 22 percent) as plants matured. However, they found that
alfalfa stem ADF concentration increased from 34 percent at an early vegetative stage
to 55 percent at the late seed pod stage. Aman (1985) reported that red clover
herbage digestibility decreased with maturity and that the component responsible for
this decrease was an increase in ADF concentration of stems. Birdsfoot trefoil ADF
concentration also increases as plants mature. Despite the increase in lignin, birdsfoot
trefoil has been reported to contain similar or increased digestibility compared to

alfalfa and red clover as plants mature (Marten and Jordan, 1979).

Crude protein

Crude protein is composed of both rumen degraded and rumen escape protein,
and contains N from both cell-soluble contents and cell-walls (Van Soest, 1967).
Crude protein is determined by measuring the amount of total nitrogen in a legume
sample using a Kjeldahl modified nitrogen technique (AOAC, 1975), and then
multiplying total nitrogen by a factor of 6.25. The factor of 6.25 is based upon the
fact that proteins contain 16 percent nitrogen (AOAC, 1975).

Crude protein concentration in forage legumes is, like the fiber fractions,
correlated to plant morphological stages of development (Onstad and Fick, 1988;
Sanderson et al., 1989; Ohlsson and Wedin, 1989). Crude protein concentration of

legumes decreases as plants mature (Moline and Wedin, 1969; Latheef et al., 1988).

8
Along with other researchers, Smith (1981) confirmed that alfalfa has a higher CP

concentration at earlier than at later stages of development. Other researchers have
quantified the decline in alfalfa CP concentration with maturity. Kalu and F ick
(1983) quantified the decline in alfalfa CP concentration using an index based on the
mean stage by weight (MSW) of the plant. Plant MSW is an average of the
individual stages present in the herbage sample weighted for the dry weight of the
herbage in each stage number (Kalu and Pick, 1983). Kalu and Pick (1983) reported
that CP concentration of alfalfa leaves decreased 3 to 9 percentage units between stage
0 (early vegetative) and stage 2 (late vegetative) and 5 percentage units between stage
3 (early bud) and stage 9 (ripe seed pod). Furthermore, Kalu and Pick found that CP
concentration in alfalfa stems declined from 2 to 3 percentage units between stage 0
and stage 2, and alfalfa stems decreased less than 2 percentage units in CP
concentration beyond stage 2.

The decline in crude protein concentration with alfalfa maturity is, as with
fiber, due in large measure to a decrease in the leaf: stem ratio of the plant (Marten et
al. , 1988). These researchers documented that although alfalfa leaves retained a high
CP concentration during the growing season, at later morphological stages of growth
the plant stems became the predominant part of the plant, causing a decline in CF
concentration of the total herbage. Buxton et al. (1985) found that CP concentration
of alfalfa leaves declined continuously from vegetative to early seed stages.

Faberger (1988) reported a linear decline in CF concentration of red clover
herbage as plant phenological stages advanced. Faberger found that at early maturity,

red clover had 27% CP, but at late maturity, CP concentration was 16%. He also

9
found that DM yield of red clover increased with maturity, concluding that the

increase in DM yield was associated with the decline in CF concentration of the
plants. At advanced stages of maturity, birdsfoot trefoil may have a similar protein
concentration to alfalfa (Marten and Jordan, 1979). MacGraw and Marten (1986)
compared protein concentration of leaves and herbage in alfalfa and birdsfoot trefoil
and found that, at early stages of maturity, alfalfa and birdsfoot trefoil leaves had 38
and 31 percent CP, respectively. As plants advanced in maturity, however, both

alfalfa and birdsfoot trefoil herbage contained 29 percent CP.

Escape protein

Part of the value of forage protein fed to ruminants is dependent on the
amount that escapes ruminal fermentation because this escape protein is directly
available for intestinal digestion and absorption (Broderick, 1978; Mullahey et al.,
1992). After meeting the requirement of microbes for rumen degraded protein,
legumes ideally would provide undegraded or escape protein to supply any protein
deficit of the animal (Erasmus et al, 1988). Escape protein is believed to be mostly
associated with nitrogen located in the plant cell-walls (Griffin et al., 1991), which
represents 5 % of the total herbage N (Howarth, 1988).

One way to measure escape protein is to quantify the amount of protein
remaining in a sample using an i_r_1 _si_tu digestion technique. The i_r_1 si_tu technique
consists of suspending forage material in the rumen, thus creating contact with the
rumen environment. This technique allows determination of forage EP by measuring

nitrogen disappearance over time (Sauer et al., 1983; Stern and Calsamiglia, 1991).

10
Undegraded forage N is then determined by subtraction from the original herbage

sample (Anderson et al., 1988). The in s_itu_ technique is widely used for forage
digestibility estimates because it is inexpensive, simple, rapid, and reproducible
(Mehnrez and Orskov, 1977). Due to its increased popularity, this technique has
been put under continuous evaluation and criticism. Factors such as bag pore size,
sample size, and sample particle size have been evaluated using the i_n sifl
digestibility technique (Nocek, 1988).

Legume escape protein concentration has been reported to increase at advanced
stages of plant maturity (Griffin et al., 1991). Griffin et al. (1991) reported that
alfalfa EP concentration was a linear function of MSW, increasing from 5 to 15 % of
the CP as plants matured. Stern and Calsamiglia (1991) agreed with those results,
suggesting that legumes had higher rumen degradable protein at earlier stages of plant
maturity than at later stages. Other researchers also have suggested that escape
protein increases with plant maturity because of the decrease in the leaf: stern ratio
(Marten, 1970; Kuhbauch and Pletl, 1981).

Although red clover and birdsfoot trefoil are probably the most important
forage legumes in the USA after alfalfa (Tesar, 1978; Barnes and Sheaffer, 1985;
Grant and Marten, 1985; Van Keuren and Hoveland, 1985), few reports are available
about their escape protein values. There is also little data on the effect of maturity on
EP concentrations of legumes. However, Griffin et al. (1991) found that alfalfa EP
concentration increased with advancing maturity and suggested that the increase in EP
may be because of an increase in maturing stems of alfalfa. Alfalfa has also been

suggested to have lower escape protein than red clover at similar stages of maturity

 

11

(Albrecht et al. 1991). There is no published information about EP concentration of
birdsfoot trefoil. However, as in alfalfa and red clover, EP concentration of birdsfoot
trefoil is likely to increase with advancing maturity.

Due to the lack of data on EP concentration for these legumes with advancing
maturity, we undertook an experiment to evaluate EP concentration of three temperate
forage legumes. The specific objectives of this experiment were:

1. to evaluate the effect of harvest schedule and plant maturity stage at harvest on
yield and forage quality of alfalfa, red clover, and birdsfoot trefoil; and 2. to compare
protein degradability of the three forage legumes at different stages of maturity by

using an i_n_ _si_tu digestibility technique.

MATERIALS AND METHODS

This study was conducted in 1991 and 1992 at the Michigan State University
Research Farm at East Lansing, Michigan. The soil was a well-drained Conover
Loam (Ochraquafls, fine loamy, mixed, mesic) with pH 7.4. Soil tests indicated 134
kg of phosphorus, 403 kg of potassium, 3961 kg calcium, and 484 kg of magnesium
per hectare.

Three forage legumes, ’Big Ten’ alfalfa, ’Arlington’ red clover, and ’Norcen’
birdsfoot trefoil, were established on 15 May 1991. Alfalfa and red clover were
seeded at 18 kg ha’1 and birdsfoot trefoil was seeded at 11 kg ha‘1 in plots measuring

0.9 by 7.6 m. Alfalfa and red clover seeds were inoculated with Rhizobium meliloti

 

(Nitragin Co., Milwaukee, WI). Birdsfoot trefoil was inoculated with Rhizobium
him—Iii (Nitragin Co., Milwaukee, WI).

The experiment was designed as a randomized complete block design (RCBD)
with four replications and two factors in a split-plot arrangement. Factor A (main
plots) was legume species (alfalfa, red clover, and birdsfoot trefoil) and factor B
(subplots) was cutting date (early, medium, and late).

On 16 April 1991, prior to plowing, the field was treated with glyphosate (N-
phosphonomethyl glycine) at 2.2 kg a.i. ha'1 to control existing legumes and perennial
grasses in the field. The field was then moldboard plowed on 2 May. On 13 May,
the field was treated with EPTC (S-ethyl dipropylthiocarbamate), preplant
incorporated at 3.3 kg a.i. ha“. To control broadleaf weeds, butyrac 200 (4-(2,4-

dichlorophenoxy) butyric acid) was applied at 1.1 kg a.i. ha'l on 14 June. Irrigation

12

13

(25.4 mm) was applied to the field on 20 June due to lack of normal precipitation.
Permethrin ((3-phenoxyphenyl)methyl(i)-_cis,_t;_a_ns—3-(2,2-dichloroethenyl)-2,2-
dimethylcyclopropanecarboxylate)) and carbaryl (l-naphthyl-N-methylcarbamate) were
applied at 0.1 and 1.1 kg a.i. ha'l on 27 June and 13 August, respectively, to control
leafhopper (Emmasca gable Harris). On 19 August 1992, the field was again
sprayed, this time with permethrin at 0.1 a.i. kg"1 to control leafhopper. Weather
data (Table 1) and accumulation of growing degree days (GDD) (Appendix Table A1)
were obtained from the Regional Weather Service Office at Michigan State University
at East Lansing, MI.

Over the two years (1991 and 1992) all forage legumes were subjected to five
harvest cycles. Within each harvest cycle, species were cut at 3 cutting dates (early,
medium, and late). Cutting dates for the seeding year (1991) were 10, 19, and 31
July 1991 for harvest cycle 1; 13, 22, and 29 August 1991 for harvest cycle 2.
Cutting dates for the following year (1992) were 15 and 26 May and 6 June 1992 for
harvest cycle 3; 1, 9, and 18 July 1992 for harvest cycle 4; and 10, 19, and 28
August 1992 for harvest cycle 5.

legume plots were harvested using a Jari sickle-bar mower (Jari Division of
Year-A-Round Cab Corp. , Mankato, MN). At the last cutting date of each harvest
cycle, all plots were uniformly clipped and those plots were not used for data
collection again that year. Yields were determined on a dry matter basis.
Approximately 700 g of herbage was subsampled from each harvested plot from each

replication for determination of dry matter and forage quality. Forage subsamples

14

were dried at 65°C for 72 hr. Forage subsamples were then ground (2 mm) in a
Wiley mill and used for forage quality determination.

Mean stage by weight (MSW), as defined by Kalu and Fick (1983), is the
average of the individual stages present in the herbage sample, weighted for the dry
weight of the herbage at each stage number. Alfalfa, red clover, and birdsfoot trefoil
MSW values for this experiment were obtained by classifying 40 stems randomly
selected from a subsample composited across replications for each harvest cycle,
species, and cutting treatment combination (Appendix Table A2). Alfalfa MSW was
quantified according to the system of Kalu and Fick (1983), which classifies stages of
development as: vegetative (0=early vegetative, 1=mid vegetative, and 2 =late
vegetative), bud (3 =early bud and 4=late bud), flowering (5 =early flower and
6=late flower), and reproductive (7=early seed pod, 8=late seed pod, and 9=ripe
seed pod). An eight-number staging system similar to Kalu and Fick’s system was
developed for the staging of red clover and birdsfoot trefoil. Red clover stages of
maturity were: no flowers (vegetative= 1), flowers (flower stage=5), and seed pods
(reproductive stage =8). Birdsfoot trefoil stages of maturity were: no flowers
(vegetative=l), 1 to 2 flowers (early flower=5), 2+ flowers (late flower=6), 1 to 2
immature seed pods (early seed pod=7), and 2’ seed pods (late seed pod=8).

Acid detergent (ADF) and neutral detergent fiber (NDF) for the three legumes
were determined according to Goering and Van Soest technique (1970). Ground
forage samples (0.50 g) were boiled in acid detergent or neutral detergent solution
for 1 hr and then rinsed with hot water (90°C) and acetone. Samples were dried

(100°C) for dry residue determination and then ashed at 500°C for 12 hr. Acid

15

detergent and neutral detergent fibers were expressed on a dry matter basis, and they
were corrected for the ash component.

Crude protein concentrations for the three legume species were obtained by a
modified Kjeldahl procedure using hydrogen peroxide (Watkins et al., 1987). Total
crude protein was then calculated as N x 6.25 in the herbage sample on a dry matter
basis.

Ruminal EP concentrations of the three legume species at each cutting date
were determined by the i_n si_tu bag technique described by Blasi et al. (1990).
However, in contrast to their technique, a different bag pore size and preincubation
time was used in this experiment. In 1991 and 1992, two ruminally cannulated
Holstein steers, averaging 550 and 480 kg in the two years, respectively, were used
during the in si_tu experiment. They were fed an ad libitum mixed alfalfa/brome

(Bromus inermis L.) hay ration (58% NDF, 46% ADF, and 23% CP) twice a day at

 

0900 and 1700 and 0.5 kg animal‘l soybean meal Mine M L. (Merr.)] once a
day at 1700. Steers consumed an average of approximately 14 kg DM clay'1 in 1991
and 11 kg DM day'1 in 1992. During both years, the steers were housed indoors.
Water was available at all times and the basal diet was given to steers for two weeks
prior to the in gig bag incubation.

Quadruplicate sets of nylon bags (pore size 53 um) containing the forage
samples (5.0 g) were put into the steers’ rumens at 1700 before feeding. Forage
treatment combinations were randomly assigned to steers at 36 bags steer“l run". The

bags were placed into the steers for two consecutive days followed by three days off

16

between incubations. Before ruminal incubation, the bags were soaked in 39°C tap
water for 15 min. Bags were removed from the rumen 16 hr after insertion.

In an associated experiment using the same Holstein steers, blank bags were
placed into the steers to assess ruminal microbial attachment to the sample bag during
i_n si_tu incubation. However, the percent of microbial CP found in the blank bags
was less than 0.5 percent of the total percent of EP calculated from the herbage
samples (1.5 %CP) (K. Cassida, 1993, personal communication); therefore, no
correction was made for microbial contamination on this in m experiment.

After removal from the rumen, bags were immediately rinsed with tap water
(approximately 1.5 hr) until the rinse water remained clear. Bags were dried in a
forced-air oven at 55°C for 24 hr. Percent residual dry matter was calculated from
the dry forage residue samples. Escape protein concentration on the residual herbage
sample was calculated as N x 6.25. Total EP concentration of the original forage
sample measured as a percentage of the original crude protein of the herbage was
calculated using the following formula:

EPq, = EPdm/CP,1m [1]
where EPdm = escape protein concentration of the original sample as a percent of dry
matter, CPdm = crude protein concentration of the original sample as a percent of dry
matter.

EP‘,m = (%EP of i_n si_tu residue x (l-ISDMD)) x 100 [2]
where %EP of i_n si_tg residue = escape protein concentration of ill m residue,
ISDMD = in situ dry matter digestibility or degradable dry matter of the herbage

sample, calculated using:

17
ISDMD = ((original sample weight-i_n git; dry residue weight)/original sample

weight» x 100 [3]-
Analysis of variance (ANOVA) for DM yields, NDF, ADF, CP, and EP
concentrations, both by harvest cycle and by legume species within cycles, was
conducted using SAS (SAS, 1986). Means for DM yield, CP, ADF, NDF, and EP
concentrations were separated by Fisher’s Protected Least Significance Difference
(LSD) test at the 5% level of significance. Simple linear regression analysis (SAS,
1986), using means pooled across harvest cycles within species, was conducted to
describe the relationship of DM yield, NDF, ADF, CP, and EP concentrations with
maturity stages as quantified by MSW and GDD. The significance of linear
regressions (PS0.05) were determined using Pearson’s correlation coefficient (SAS,
1986). Predicted mean values for DM yield, NDF, ADF, CP, and EP concentrations

were calculated from the regression equations.

RESULTS AND DISCUSSION

Mean stage by weight and growing degree days

In this study, MSW was calculated to quantify maturity of the legumes at each
cutting date (early-, medium-, and late-cutting date) within harvest cycle. Three
MSW systems were used for the legumes (Appendix Table A2) and there was no
replication for MSW within cutting date for each specie. However, there was a
numerical increase in MSW with advancing cutting date. For alfalfa, the highest
MSW value (5 .0) was obtained at late-cutting date in the fourth harvest cycle, while a
low MSW value (1.5) was obtained at early-cutting date in the third harvest cycle.
For red clover, the highest MSW value (2.8) was obtained at late—cutting date in the
fourth harvest, and a low MSW value (1.0) was obtained at early-cutting date in the
first, third, fourth, and fifth harvest cycles. For birdsfoot trefoil, the highest MSW
value (4.1) was obtained at late-cutting date in the fourth harvest cycle, while a low
MSW value (1.0) was obtained at early-cutting date in the third and fifth harvest
cycles.

Dry matter yields, NDF, ADF, CP, and EP concentrations were regressed on
GDD across harvest cycles within species to determine the relationship between GDD
and the mentioned legume parameters (Appendix Table A3). However, results from
regression analyses indicated a poor relationship between GDD and DM yields, NDF,
ADF, and EP concentrations for all three legumes. Crude protein concentration was

found to be related to GDD, but the regressions had very low r2 values for all the

18

l9

legumes. Therefore, GDD will not be discussed in the results and discussion section

of this study.

Dry matter yield

This study was carried out with soil conditions that were favorable for growing
alfalfa, red clover, and birdsfoot trefoil. Dry matter yields of the legumes for cutting
dates, averaged over legumes species, are reported in Table 2. Results for which
there was no significant species x cutting date interaction will be discussed first.
Interactions will be discussed subsequently. There was a significant effect of cutting
date on DM yield in the second and third harvest cycles. In these two harvest cycles,
DM yield increased with advancing cutting date. A significant effect of cutting date
on dry matter yield also was found in the fourth harvest cycle; however, in contrast to
the second and third harvest cycles, DM yield was higher at late- than at early- and
medium-cutting date. Moline and Wedin (1969) also reported DM yield of alfalfa to
increase 1.5 Mg ha'1 from pro-bud to first flower and 1.1 Mg ha'1 from one half
bloom to early seed pod stage of development. Latheef et al. (1988) reported DM
yield of alfalfa to increase 0.9 Mg ha‘1 from early to late bloom stage of development.
The results for alfalfa do not agree with those reported by Fulkerson et al. (1967),
who found DM yield of alfalfa to decrease 0.4 Mg ha'1 as herbage passed from bud to
early seed pod stage of development. Our results for red clover agree with those
reported by Colville and Torrie ( 1962), who found that DM yield of red clover
increased 0.34 Mg ha'1 as red clover passed from mid-vegetative to late bud stage of

development. Other researchers have also reported increases in DM yield with

20
advancing maturity of alfalfa (Nelson and Smith, 1968; Weir et al., 1960; Winch et

al., 1970), red clover (Van Keuren and Hoveland, 1985) and birdsfoot trefoil (Gasser
and Lachance, 1969; MacGraw and Marten, 1986).

There was no significant effect of species on DM yield during the second,
third, and fourth harvest cycles (Table 3). Other researchers have reported
differences in DM yield when comparing alfalfa and red clover (Smith, 1962) or
alfalfa and birdsfoot trefoil (Smith and Nelson, 1967; MacGraw and Marten, 1986),
with alfalfa producing higher DM yield than either red clover or birdsfoot trefoil.
Dry matter yields of alfalfa and red clover in this experiment are lower than DM
yields expected under similar growing conditions. However, DM yields of birdsfoot
trefoil are in the normal range reported by other researchers. Tesar (MSU,
unpublished data) reported DM yield for alfalfa of 13.3 Mg ha'1 in a two-year study.
Similar DM yield for alfalfa was reported by Hesterman et al. (1989) in a three-year
study. Sheaffer (1986) reported DM yield for red clover between 9.5 and 10.3 Mg
ha“, with a 2 to 4 cut system. Birdsfoot trefoil has been reported to yield 8.6 Mg ha‘
1 by Tesar (1978) in a four-year study, while Leep and Lempke (1986) reported DM
yields of 7.6 Mg ha“1 for birdsfoot trefoil in two years of a three-year study. All
these studies, except the experiment for red clover by Sheaffer, were conducted at
East Lansing, MI.

In the first and fifth harvest cycles there was an interaction between species
and cutting date (PS0.05) for DM yield (Table 4). In the first harvest cycle, DM
yield of red clover and birdsfoot trefoil increased significantly with advancing cutting

date. However, DM yield of alfalfa was not significantly affected by cutting date. In

21
the fifth harvest cycle, DM yield of red clover and birdsfoot trefoil increased

significantly at each cutting date level, while DM yield of alfalfa plateaued at
medium-cutting date. MacGraw and Marten (1986) also reported an interaction
between cutting date and legume species for DM yield. However, they found that
DM yield increased with advancing maturity of alfalfa, while it plateaued at late
flower stage for birdsfoot trefoil.

Regression analysis of DM yield data pooled across harvest cycles within

lT-"“”‘ "'l

species revealed that MSW was an inadequate predictor for DM yield of alfalfa
(Appendix Table A4). However, MSW was a significant linear predictor for DM

yield of red clover and birdsfoot trefoil (Figure 1).

Neutral detergent fiber concentration.

There was a significant effect of cutting date on NDF concentrations in the
first, second, and fourth harvest cycles (Table 2). In the first cycle, NDF
concentration was greater at medium— and late- than at early-cutting date. In the
second harvest cycle, N DF concentration was greater at late- than at early-cutting
date. In the fourth harvest cycle, NDF concentration was higher at late- than at either
early- or medium-cutting date. These results agree with those reported for alfalfa and
birdsfoot trefoil by Buxton and Brasche (1991), who reported NDF concentration to
increase 7.4 and 6.2 percentage units from early- to late-maturity, respectively, for
alfalfa and birdsfoot trefoil during the first year of a two-year study. Sanderson and
Wedin (1988 and 1989) also reported increases in NDF concentration with maturity

for alfalfa and red clover, as did Griffin et al. (1991) for alfalfa.

22

A significant effect of species on NDF concentration was found in the first and
fourth harvest cycles (Table 3). In the first harvest cycle, alfalfa had higher NDF
concentration than either red clover or birdsfoot trefoil. In the fourth harvest cycle,
NDF concentration of alfalfa was greater than red clover, while no differences in
NDF concentration were found between alfalfa and birdsfoot trefoil and between red
clover and birdsfoot trefoil. These results do not agree with those reported by Buxton
and Brasche (1991), who found no significant difference in NDF concentration
between alfalfa and birdsfoot trefoil when using an equal MSW system for both
species.

There was an interaction between species and cutting date (P s 0.05) for NDF
concentration in the third and fifth harvest cycles (Table 4). In the third harvest
cycle, NDF concentration significantly increased with cutting date for all three
legumes. However, the extent of increase in NDF concentration of alfalfa and
birdsfoot trefoil was higher (13 percentage units for both legumes) than for red clover
(7.5 percentage units). In the fifth harvest cycle, N DF concentration of alfalfa
increased at each succeeding cutting date, while N DF concentrations for red clover
and birdsfoot trefoil were significantly higher at late- than at early- and medium-
cutting date. Other researchers have also reported interactions between legume
species and cutting date for NDF concentration (Buxton and Horstein, 1986; Buxton
and Brasche, 1991). Buxton and Brasche (1991) reported an interaction for NDF
concentration between sampling dates for alfalfa and birdsfoot trefoil in a two year
study. They found that during both years, NDF concentration for alfalfa had a larger

rate of increase than for birdsfoot trefoil.

 

23

Results from regression analysis indicated that MSW was a significant
indicator of NDF concentration for alfalfa, red clover, and birdsfoot trefoil when data
across all harvest cycles within species were pooled (Figure 2). These results clearly
agree with the results in our AN OVA table, and further show that the increase in
NDF concentration with cutting date was linear. These results agree with those
reported by Olhsson and Wedin (1989) and Sanderson and Wedin (1989), who found
a linear increase in N DF concentration for red clover with MSW. Buxton et al.
(1985) suggested that an increase in NDF concentration with increasing MSW for red
clover may be because red clover leaves do not readily abscise after they mature,
resulting in a greater proportion of old leaves with advancing maturity. Griffin et a1.
(1991) reported a linear increase in N DF concentration for alfalfa with MSW.
However, our results do not agree with results reported by Kalu and Fick (1983) and
Sanderson and Wedin (1989), who found a quadratic increase in NDF concentration
for alfalfa with increasing MSW. They looked at N DF concentration for alfalfa over
a larger range of MSW values (0 to 9) than we did (1.5 to 5) (Appendix Table 2).
Therefore, with the narrow MSW range found in this study, legumes did not mature
enough to show as great changes in NDF concentration as those found by Kalu and

Fick.

Acid detergent fiber concentrations
A significant effect of cutting date on ADF concentration was obtained in the
first, second, and third harvest cycles for the three species as reported in Table 2. In

the first and second harvest cycles, ADF concentration was higher at medium- and

24
late- than at early—cutting date. In the third harvest cycle, there was a significant

increase in ADF concentration at each cutting date. These results agree with those
reported by Kalu and Fick (1983), who found that ADF concentration in alfalfa leaves
increased 9 percentage units from early vegetative to early bud stage, while
concentration in alfalfa stems increased 17 percentage units from early vegetative to
early bud stage and 1 to 2 percentage units from early bud stage to seed pod stage.
Horstein et al. (1989) supported Kalu and Fick’s results, finding that an increase in
ADF concentration of legumes was due to a decrease in the leaf: stern ratio with
advancing maturity.

There was a significant effect of species in the third harvest cycle on ADF
concentration (Table 3). Alfalfa had a higher ADF concentration than either red
clover or birdsfoot trefoil, while these later two legumes had equal concentrations of
ADF. Despite the increase in fiber, NDF and ADF concentrations of the legumes are
lower than those reported by other researchers at comparable stages of maturity of the
legumes. Neither NDF nor ADF concentrations increased as much as expected with
advancing cutting date of the legumes, perhaps because of the short cutting interval
between cutting date. Paling (1992) reported NDF and ADF concentrations for
alfalfa of 41.7 and 32.3%, respectively, in a two-year study near the site where this
experiment was established. Hesterman et al. (1989) reported NDF and ADF
concentrations for alfalfa of 43.3 and 35.9% , respectively, during a three-year study
at East Lansing, MI. In both preceding experiments, alfalfa was harvested at 10%

bloom stage of maturity.

25
During the fourth and fifth harvest cycles, there was an interaction (PS0.05)

between species and cutting date for ADF concentration; therefore, significant cutting
date differences within species for these harvest cycles are reported in Table 4. In the
fourth harvest cycle, ADF concentration of alfalfa and birdsfoot trefoil increased
significantly from early- to medium-cutting date, where it plateaued. For red clover,
ADF concentration did not increase from early- to medium-cutting date, but it
increased sharply from medium— to late-cutting date. In the fifth harvest cycle, ADF
concentration for alfalfa increased significantly from early- to medium-cutting date
and it plateaued at medium-cutting date. For red clover and birdsfoot trefoil, ADF
concentrations were significantly lower at early and medium- than at late-cutting date.

When pooled data were regressed across harvest cycles for each of the three
legume species, results indicated that MSW was not a significant predictor of ADF
concentration for alfalfa (Appendix Table 4). However, MSW was an adequate
predictor of ADF concentration for red clover and birdsfoot trefoil (Figure 2). These
results for alfalfa do not agree with those reported by Kalu and Fick (1983) and
Griffin et al. (1991), who found a linear relationship between MSW and ADF
concentration for alfalfa. However, results for red clover agree with those reported
by Sanderson and Wedin (1989), who found a linear relationship between ADF

concentration and MSW for red clover.

Crude protein concentration
There was a significant effect of cutting date on CP concentration in the third,

fourth, and fifth harvest cycles (Table 2). In the third harvest cycle, CP

26

concentration was greater at early- and medium- than at late—cutting date. These
results agree with those reported by Silkerson et al. (1967), who found CP
concentration for alfalfa to decrease 4.5 percentage units from bud to first flower
stage and 0.6 percentage units from full bloom to early seed pod stage. Similarly,
Moline and Wedin (1969) found CP concentration for alfalfa to decrease 2.9
percentage units from pre-bud to first flower stage, 1.4 percentage units from one-half
bloom to three-fourth bloom stage, and 0.8 percentage units from full bloom to early
seed pod stage. Sanderson and Wedin (1989) also reported CP concentration for
alfalfa to decrease with advancing maturity. However, in the fourth and fifth harvest
cycles, CP concentration was significantly higher at medium- and late-cutting date
than at early-cutting date. From a practical point of view, these small increases in CP
concentration (0.4 and 0.6 percentage units) with increasing maturity are probably
unimportant.

Possible reasons for the increase in CF concentration were cool temperature
during the fourth and fifth harvest cycles. Air temperature in both harvest cycles
was 3°C below normal (Table 1), and this relatively low temperature could delay
maturation of the legumes and reduce the decline in quality (W algenback, 1983).
Other authors have also reported alfalfa CP concentration to increase under warm
temperatures compared to cool temperatures (Smith, 1969; Marten, 1970). However,
during the fourth and fifth harvest cycles, MSW values indicated that the legumes
matured faster during these harvest cycles than during the first, second, and third

harvest cycles (Appendix Table A2).

27

N 0 significant effect of species was obtained for CP concentration during any
of the five harvest cycles (Table 3). Also, there was no species by maturity
interaction for CP concentration for the legumes during any of the harvest cycles.

The response of CP concentration of the legumes was not consistent during the
experiment. However, for both years (1991 and 1992), CP concentrations were equal
for the three legumes (23 %), and these CP concentrations are higher than CP
percentages reported for alfalfa by Hesterman et al. (1989) (21.7%) and Paling (1992)
(19.1%). Carlson et al. (1983) reported CP concentrations for birdsfoot trefoil
between 16.2 and 20% when harvested three times in a two year study.

When regression analysis was performed across harvest cycles within species
(Appendix Table A4), mean stage by weight was not a good predictor of CP
concentration for alfalfa, red clover, or birdsfoot trefoil. These results do not agree
with results reported by Kalu and Fick (1983) and Faberger (1988), who reported a
quadratic relationship between MSW and CP concentration for alfalfa and red clover,
respectively. Griffin et al. (1991) also found a quadratic increase in CP concentration
with increasing MSW for alfalfa, but they found a wider range for MSW (from 0 to

8) than the MSW range in this study (from 0 to 5).

Escape protein concentration

In the first, second, third, and fourth harvest cycles, there was a significant
effect of cutting date on EP concentration (Table 2). In the first and second harvest
cycles, EP concentrations were greater at late- than at early-cutting date, and no

differences in EP were found between early- and medium- or between medium- and

28

late-cutting date. In the third harvest cycle, EP concentration increased with
advancing cutting date. In the fourth harvest cycle, EP concentration was greater at
late- than at early- and medium-cutting date. These results agree with those reported
by Griffin et al. (1991), who found that EP concentration of alfalfa, as a percent of
total CP in the original sample, increased as plants passed from early flower (5%) to
late seed pod (15 %), while there was no increase from early to late vegetative stages
of development (1.5 %). There are little data on EP concentrations in legumes, but
other authors have reported EP concentrations in grass to increase with advancing
maturity. Blasi et al. (1991) reported that EP concentrations of bromegrass MID—118

inermis Leyss) and big bluestem Andro on gerardii Vitman) increased as they

 

advanced in maturity. Mullahey et al. (1992) reported EP concentration of
switchgrass (Panicum virgatum L.) to increase with advancing maturity, while EP
concentration of bromegrass did not change with plant maturity.

A significant effect of species on EP concentration was found in the third
harvest cycle (Table 3). In the third harvest cycle, alfalfa and birdsfoot trefoil had
greater EP concentration than did red clover. There was no significant effect of
species on EP concentration for the other four harvest cycles. Results for red clover
do not agree with results reported by Albrecht et al. (1991), who found EP
concentration of red clover to be higher than EP concentration of alfalfa.

There was an interaction between species and cutting date for EP concentration
in the fifth harvest cycle (Table 4). In this harvest cycle, EP concentration of alfalfa

was not affected by cutting date. Escape protein concentration of red clover

29

decreased from early- to medium-cutting date, while EP of birdsfoot trefoil increased
from early- to medium-cutting date.

When EP concentration was regressed across all harvest cycles within legume
species, results indicated that MSW was an adequate predictor of EP concentration of
red clover (Figure 3); however, MSW was not a good predictor of EP concentrations
of alfalfa and birdsfoot trefoil (Appendix Table A4). These results for alfalfa do not
agree with results reported by Griffin et al. (1991), who reported a linear increase in
EP concentration of alfalfa with MSW. There is a lack of information relating
concentration of EP to maturity of legumes. However, in general, with advancing
maturity the proportion of leaf to stem decreases in herbage (Buxton et al, 1985),
increasing the amount of plant cell-wall and, therefore, increasing the concentration of
fibers and lignin in herbage. Escape protein concentration is also expected to increase
as cell-wall mass increases with plant maturity (Griffin et al., 1991) because most of

the N that escapes rumen fermentation is bound to the cell-wall.

 

CONCLUSIONS AND RECOMNIENDATIONS

This experiment indicated that MSW was not a useful tool for estimating DM
yield and quality of the legumes with a few exceptions. These exceptions are DM
yield, NDF and ADF for red clover and birdsfoot trefoil, NDF for alfalfa, and EP
concentration for red clover. However, for all previous mentioned parameters, the r2
values were pretty low.

During the two-year study, legume quality declined with advancing cutting
date, the decline being more accentuated in the second than in the seeding year. This
study supports previous research reporting increases in DM yields and declines in
herbage quality of alfalfa, red clover, and birdsfoot trefoil with advancing maturity.
However, DM yields were not compromised with the quality of the legumes at
advancing maturity because maximum MSW values were 4 (late bud) for alfalfa, 2
(late vegetative) for red clover, and 3 (early bud) for birdsfoot trefoil. At these
maturity levels, the highest N DF concentration was 41% for alfalfa and 37% for both
red clover and birdsfoot trefoil, while the highest ADF was 31% for alfalfa, 29% for
red clover, and 28% for birdsfoot trefoil. Crude protein concentrations of the
legumgs were not affected consistently neither by species nor by maturity, but all

three legumes had 23% CP at the late-cutting date.

30

31
Van Soest (1982) and Hesterman et al. (1991) have suggested that high quality

legumes contain more than 19% CP, and less than 40 and 31% NDF and ADF,
respectively. Using this criteria, I conclude that the late-cutting date was the best
harvest time for alfalfa, red clover, and birdsfoot trefoil. This maturity stage
corresponded to late bud for alfalfa, late vegetative for red clover, and early bud stage
for birdsfoot trefoil. The legumes in this experiment were harvested at an earlier
maturity level than current harvest recommendations which are: 10% bloom for
alfalfa, prebloom to early-bloom for red clover, and full flower for birdsfoot trefoil
(Smith, 1972; Leep and Tesar, 1981; Taylor, 1985).

In this experiment, the EP concentrations found in alfalfa, red clover, and
birdsfoot trefoil are not high enough to contribute a great deal to the EP
recommended for supplementing ruminant diets. Conrad and Klopfenstein (1988)
have suggested that cattle rations should contain 50% of the digestible crude protein
as EP. However, during this study, there was a continuous increase in EP
concentrations for the legumes from early- to late-cutting date. This means that EP
concentrations could continue increasing with advancing cutting date, especially for
alfalfa and birdsfoot trefoil, which tended to have higher EP concentrations than did
red clover. Therefore, I conclude that all three legumes can be of particular interest
to animal nutritionists looking for legume EP sources for feeding animals; however,
When feeding rations relying solely on legumes, an EP supplement may be required.

I recommend that the MSW system used in this experiment be tested further in
order to establish its consistency in predicting DM yield and forage quality of the

1081111168. Also, for achieving greater precision in quantifying the relationship of yield

32

and quality parameters to MSW, I recommend that every single plot of legumes be
harvested and quantified for maturity instead of a composited sample of the legume.
Furthermore, I recommend increasing the cutting interval between maturity stages
within harvest cycles in order to better assess the maturity stages of legumes using
MSW. Finally, I recommend further studies relating MSW and EP concentrations of

the legumes because this is a relatively new field.

33

Table 1. Air temperature and precipitation'i in spring and summer of 1991 and 1992
at the Agronomy Farm at Michigan State University, East Lansing, MI.

 

 

 

Tempemture (°C) Rainfall (mm)
Max Min Avg. 30 year meanzl: Total 30 year mean:

l9_91

April 16 5 10 8 104 71
May 24 12 18 14 42 69
June 28 14 21 19 74 90
July 28 16 22 22 91 77
August 27 14 21 21 74 79
&

April 1 1 2 7 8 97 71
May 21 8 14 14 41 69
June 24 10 17 19 64 90
July 24 14 19 22 182 77
August 24 12 18 21 37 79

 

TWeather data collected from the Horticulture Experiment Station at Michigan State
University at East Lansing, MI.
:l:Long term (1951-1980) mean from the Regional Weather Office at Michigan State
University at East Lansing, MI.

34

Table 2. Effect of cutting date on dry matter (DM) yield, neutral detergent fiber
(NDF), acid detergent fiber (ADF), crude protein (CP), and escape protein (EP)
concentrations of alfalfa, red clover, and birdsfoot trefoil for five harvest cycles in
1991 and 1992.

 

 

 

 

 

Cutting date
Early Medium Late c.v. mm, m

1" harvest cycle‘l'

DM yield (Mg/ha) «i -- -- --
NDF (% of DM) 33.0a 35.6" 366" 6.6
ADF (% of DM) 23.3a 25.2b 26.2b 8.6
CP (% of DM) 23.5 23.6 23.5 0.7
EP (% of CP) 6.4“ 7.2"b 8.4b 19.0
2"d harvest cvcle

DM yield (Mg/ha) 1.7“ 2.7" 3.2c 5.2
NDF (% of DM) 33.6‘ 35.6ab 37.6b 8.7
ADF (% of DM) 25.0a 29.1b 28.7b 10.8
CP (% of DM) 23.4 23.5 23.6 0.9
EP (% of DM) 62‘ 6.9" 7.7° 21.0
3" harvest cycle

DM yield (Mg/ha) 2.1a 3.9" 5.1c 9.6
NDF (% of DM) «1: -- -- --
ADF (% of DM) 21.8’I 27.7b 32.4° 8.6
CP (% of DM) 23.28 23.28 22.1" 1.0
EP (% of DM) 37‘ 4.7" 6.0c 17.9

 

1'1" Harvest cycle: 10, 19, and 31 July 1991; 2°° Harvest cycle: 13, 22, and 29
August 1991; 3rd Harvest cycle: 15 and 26 May and 6 June 1991.

:tSignificant interaction effect between species and cutting date. See Table 4 for
interaction effects.

“Numbers within rows followed by the same letter are not significantly different as
determined by Fisher’s protected LSD (P5005).

35
[Table 2 (con’t)].

 

 

 

 

 

Cutting date
Early Medium Late C.V. mm, W

4th h_aLrvest cycle‘l'

DM yield (Mg/ha) 2.5a 2.8a 3.4b 17.7
NDF (% of DM) 32.9a 37.7b 40.7c 5.9
ADF (% of DM) «1: -— -- --
CP (% of DM) 22.0‘ 224° 22.4" 0.9
EP (% of CP) 49' 5.9‘ 7.72" 24.6
5'h harvest cvcle

DM yield (Mg/ha) --:l: -- -- --
NDF (% of DM) “1: -- -- --
ADF (% of DM) "t -- -- --
CP (% of DM) 23.0ll 23.6b 23.6b 1.0
EP (% of CP) --:l: -- -- --

 

1'1“ Harvest cycle: 10, 19, and 31 July 1991; 2“‘1 Harvest cycle: 13, 22, and 29
August 1991; 3" Harvest cycle: 15 and 26 May and 6 June 1991; 4‘h Harvest cycle:
1, 9, and 18 July 1992; 5th Harvest cycle: 10, 19, and 28 August 1992.

:tSignificant interaction effect between species and cutting date. See Table 4 for
interaction effects.

“Numbers within rows followed by the same letter are not significantly different as
determined by Fisher’s protected LSD (PS0.05).

36

Table 3. Effect of forage species on dry matter (DM) yield, neutral detergent fiber
(NDF), acid detergent fiber (ADF), crude protein (CP), and escape protein (EP)
concentrations of alfalfa, red clover, and birdsfoot trefoil for five harvest cycles in
1991 and 1992.

 

 

 

 

Species
Alfalfa Red clover Trefoil C.V.specim

1" harvest cvcle'l'

DM yield (Mg/ha) "i -- -- --
NDF (% of DM) 38.33 340° 329" 3.6
ADF (% of DM) 26.0 24.7 24.0 5.1
CP (% of DM) 23.5 23.5 23.5 0.2
EP (% of CP) 7.6 6.4 8.0 6.7
2‘" harvest cycle

DM yield (Mg/ha) 2.5 2.7 2.4 5.3
NDF (% of DM) 37.4 34.1 35.2 3.4
ADF (% of DM) 28.5 27.8 26.7 4.5
CP (% of DM) 23.6 23.5 23.6 0.2
EP (% of CP) 7.3 6.7 6.9 3.8
3" harvest cycle

DM yield (Mg/ha) 3.8 3.7 3.5 5.6
NDF (%) "i -- -- --
ADF (%) 30.2”I 25.0" 266" 3.4
CP (%) 22.9 22.8 22.8 0.4
EP (%) 5.8a 3.7" 5.1a 8.3

I

 

‘l'l’t Harvest cycle: 10, 19, and 31 July 1991; 2" Harvest cycle: 13, 22, and 29
August 1991; 3" Harvest cycle: 15 and 26 May and 6 June 1992.

:tSignificant interaction effect between species and maturity. See Table 4 for
interaction effects.

“Numbers within rows followed by the same letter are not significantly different as
determined by Fisher’s protected LSD (P5005).

37
[Table 3 (con’t)].

 

 

 

 

Species
Alfalfa Red clover Trefoil C.V.,pccig

4‘“ harvest cycle‘l'

DM yield (Mg/ha) 2.9 2.7 3.1 5.0
NDF (% of DM) 38.5“ 35.7b 37.1“b 1.4
ADF (% of DM) nil: -- -- ~-
CP (% of DM) 22.3 22.3 22.3 0.3
EP (% of CP) 6.8 5.0 6.7 10.1
5th harvest cycle

DM yield «1 -— -- --
NDF (% of DM) "1: -- -- --
ADF (% of DM) "1 -- -- --
CP (% of DM) 23.4 23.4 23.4 0.5
EP (% of CP) -- -- -- --

 

“[1" Harvest cycle: 10, 19, and 31 July 1991; 2“d Harvest cycle: 13, 22, and 29
August 1991; 3" Harvest cycle: 15 and 26 May and 6 June 1992; 4‘h Harvest cycle:
1, 9, and 18 July 1992 and 5‘" Harvest cycle: 10, 19, and 28 August 1992.

iSignificant interaction effect between species and maturity. See Table 4 for
interaction effects.

“Numbers within row followed by the same letter are not significantly different as
determined by Fisher’s protected LSD (P5005).

38

Table 4. Interaction effect between species and cutting date on dry matter (DM)
yield, neutral detergent fiber (NDF), and acid detergent fiber (ADF) concentrations of
alfalfa, red clover, and birdsfoot trefoil for five harvest cycles in 1991 and 1992.

 

 

 

 

 

 

Species
Cutting date Alfalfa Red clover Trefoil
1““ Harvest cycle
DM yield (Mg/ha)
Early 2.2“ 1.8“I 1.3“
Medium 2.9“ 2.5“ 2.8“
Late 2.9“ 3.4“ 3.6“
01an,“, 31.0 15.0 11.8
3‘“ Harvest cvcle
m (% of DM)
Early 31.5“ 30.3“ 27.3“
Medium 38.9“ 33.8“ 36.3“
Late 44.6“ 37.8“ 40.7“
C.V.w,,,ngm 2.9 4.6 5.6
4‘“ Harvest cycle
fl (% of DM)
Early 27.1“ 22.5“I 25.2“
Medium 31.7“ 24.2“ 31.4“
Late 31.9“ 29.9“ 29.9“
C.V.wmm 3.6 6.1 8.5

 

“““Numbers within columns followed by the same letter are not significantly different
as determined by Fisher’s protected LSD (P5005).

:lzl‘t Harvest cycle: 10, 19, and 31 July; 2‘" Harvest cycle: 13, 22, and 29 August
1991; 3" Harvest cycle: 15 and 26 May and 6 June 1992; 4‘“ Harvest cycle: 1, 9,
and 18 July 1992.

[Table 4 (cont’n)]

 

 

 

Species
Cutting date Alfalfa Red clover Trefoil
5‘“ Harvest cycle
DM yield (Mg/ha)
Early 1.5“ 1.2“ 0.7“
Medium 3.5“ 2.1“ 1.9“
Late 3.5“ 3.1“ 2.5“
C.V.w,,,ng m 8.1 11.8 6.2
NDF, (% of DM)
Early 32.4“ 31.5“ 31.4“
Medium 38.3“ 30.8“ 30.6“
Late 41.0“ 36.1“ 35.0“
C'V°cutringdate 3.1 3.6 5.1
fl (% of DM)
Early 26.0“ 20.8“ 24.5“
Medium 31.0“ 22.4“ 23.2“
Late 33.2“ 26.0“ 28.0“
C.V.,,uningdatc 5.4 4.6 6.7
_E_P (% of CP)
Early 7.2“l 8.1“ 2.4“
Medium 5 .9“ 4.6“ 3.9“
Late 5.8“ 6.2““ 2.9““
C.V.wmm 19.8 29.0 18.4

 

“““Numbers within columns followed by the same letter are not significantly different
as determined by Fisher’s protected LSD (P50‘S’ 1

#1“ Harvest cycle: 10, 19, and 31 July; 2‘" Harvest cycle: 13, 22, and 29 August
1991; 3" Harvest cycle: 15 and 26 May and 6 June 1992; 4‘“ Harvest cycle: 1, 9,

and 18 July 1992; 5‘“ Harvest cycle: 10, 19, and 28 August 1992.

40

 

 

 

 

 

 

 

 

 

 

Red clover "'DM predicted
'1: 5 — + + DM meene
‘8
3..
E
a
u 3 -
"6
8.
a 2 -
5
as +
“' ’ ' DM= 1 5.5+o. 7254(MSW); r2
P<0. 05; d. f. =13
00 0:5 ‘1| 1 .15 2 2. 5 31 3.5 4 4.5 5
MSW
6
Blrdefoot trefoil ‘DM product-a

 

 

+ '1' DM meene

 

a
l

N
I

 

Percentage of dry matter yield
0
l

.e
l

+
+ DM=O.79+0.8468(MSW); r2=o.5%
+ P5055; d.f.=13

l L l
0.5 1 1.5 2 2.5 3 3.5 4 4.6 5
MSW

 

 

 

O
0

Figure 1. Dry matter (DM) yields of red clover and birdsfoot trefoil regressed on
mean stage by weight (MSW).

41.

 

 

 

 

 

 

 

 

10
Red GIOVOT —EP prodlctod
8 + EP moans
1%
s
5 ° 7
'5
0
f!” 4 -
§
:5
a. 2 P
EP=1.75+1.949(MSW); r2=046
P<0.05; d.f.=13
OO 0 5 1 1 5 2 2.5 3 3.5 4 4.5 5
MSW

Figure 3. Escape protein (EP) concentration of red clover regressed on mean stage
by weight (MSW).

42

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

50
Alfalfa ...
.5 ‘° — + +
g + + +4—
5'30 - +
"6 —NDF predicted
%20 .- + NDF meene
§
‘ 1° - NDF=30. 63+2. 37(MSW); r2=o. 44
P<0. 05; d. f.=13
00 0.1511 1522553151 4155555
Msw
50
Birdsfoot trefoil
5 ‘° ’ ., + + .. *
530 r ... ‘ _1, ..., —NDF predicted
.5 + ‘4': .— g— ‘A — + NDF meene
E, :55..- ‘ ‘ -'ADF predicted
§ 20 — A ADF meene
g 10 _ NDF=27.37+3.21(MSW); r2=o.66
ADF=21.57+2.13(MSW); r2=o.39
Ps005; d.f.l=13 . l . 1
on 0.5 1 1.5 2 2.5 a 5.5 4 4.5 5
MSW
50
Red clover
g 40 b + "’

_ %)./t —NDF predicted
€30 ‘95— " ’ 4' NDF meene
§2o P . f ‘3‘ A -- ADF predicted
g ‘ ADF "1"".
IL 10 __ NDF=28.79+3.18$MS;=1'2 0.52

ADF- 19 24+3 56 MS ;r2=0. 49
P<0. 05; d..f= 13
00 0:5 1 1. 5 2 2. 5 a 5.15 4 4:5 5

MSW

Figure 2. Neutral detergent fiber (NDF) of alfalfa, red clover, and birdsfoot trefoil
and acid detergent fiber (ADF) concentrations of red clover and birdsfoot trefoil

regressed on mean stage by weight (MSW).

REFERENCES

REFERENCES

Akin, DE. 1989. Histological and physical factors affecting digestibility of forages.
Agron. J. 81:17-25.

Albrecht, K.A., W.F. Wedin, and DR. Buxton. 1987. Cell-wall and digestibility of
alfalfa stems and leaves. Crop sci. 27:735—741.

Albrecht, K.A. 1991. Degradation of forage legume protein by rumen
microorganisms in vitro. NC-189 Progress Report, Saint Louis, Missouri.
1 Oct.-30 Sept. 1991. University of Wisconsin, Madison, WI.

Aman, P. 1985. Chemical composition and in vitro degradability of major chemical
constituents in botanical fractions of red clover harvested at different stages of
maturity. J. Sci. Food Agric. 36:775-780.

Anderson, S.J., T.J. Klopfenstein, and V.A. Wilkerson. 1988. Escape protein of
yearling steers grazing smooth brome pastures. J. Anim. Sci. 66:237-242.

AOAC. 1975. Official Methods of Analysis 13th ed. Association of Official
Analytical Chemists, Washington, DC.

Barnes, D.K. and CC. Sheaffer. 1985. Alfalfa. p. 89-97. In Maurice E. Heath,
Robert F. Barnes, and Darrel S. Metcalfe (ed.) Forages the Science of Grassland
agg'culture. 4‘“ ed. Iowa State University Press, Ames, Iowa.

Blasi, D.A., J .K. Ward, T]. Klopfenstein, and RA. Britton. 1991. Escape protein
for beef cows: III. Performance of lactating beef cows grazing smooth brome or
big bluestem. J. Anim. Sci. 69:2294-2302.

Broderick, GA. 1978. In vitro procedures for estimating rates of ruminal protein
degradation and proportions of protein escaping the rumen undegraded. J. Nutr.
108: 181.

Buxton, D.R., J.S. Horstein, W.F. Wedin, and G.C. Marten. 1985. Forage quality

in stratified canopies of alfalfa, birdsfoot trefoil, and red clover. Crop Sci.
25:27 3-279.

43

44

Buxton, DR. and MR. Brasche. 1991. Digestibility of structural carbohydrates in
cool-season grass legume forages. Crop Sci. 31:1338—1345.

Buxton, DR and J .S. Horstein. 1986. Cell-wall concentration and components of
stratified canopies of alfalfa, birdsfoot trefoil, and red clover. Crop Sci. 26:180—
186.

Brink, G.A. and G.C. Marten. 1983. Contemporary vs traditional harvest
management of alfalfa-effects on yield, quality, and persistence. p. 103. In
Agron. Abstracts. ASA, Madison, WI.

Carlson, I.T., L.J. Elling, D.A. Miller, and RR. Bauselink. 1983. Noreen birdsfoot
trefoil. Iowa State University NC 199 Coop. Ext. Serv., Ames, Iowa.

Colville, W.L. and J .H. Torrie. 1962. Effects of management on food reserves, .
root rot incidence and forage yields of medium red clover,(Trifolium pratense L.) l
Agron. J. 22:332-335.

 

Conrad, HR. and TJ. Klopfenstein. 1988. Role in livestock feeding-greenchop,
silage, hay, and dehy. p. 539-551. In Hanson A.A., D.K. Barnes, and RR. Hill
2‘“ ed. Alfalfa and Alfalfa Improvement. ASA, CSSA, and SSSA, Madison, WI.

Fagerberg, Britta. 1988. The change in nutritive value in timothy, red clover, and

lucerne in relation to phenological stage, cutting time, and weather conditions.
Acta Agric. Scand. 38:347-362.

Fick, G.W. and C. Garth Janson. 1990. Testing mean as a predictor of alfalfa
forage quality with growth chamber trials. Crop. Sci. 30:678-682.

Fulkerson, R.S., D.N. Mowat, W. E. Tossel, and J .E. Winch. 1967. Yield of dry
matter, in vitro-digestible dry matter and crude protein of forages. Can. J. Plant
Sci. 47:683-690.

Gasser, H. and L. Lachance. 1969. Effect of dates of cutting on dry matter
production and chemical content of alfalfa and birdsfoot trefoil. Can. J. Plant Sci.
49:339-349.

Goering, H.K., and R]. Van Soest. 1970. Forage fiber analyses (apparatus,
reagents, procedures, and some applications). Agric. Handbook no. 379. US.
Gov. Printing Office, Washington, DC.

Grant, W.F. and CG. Marten. 1985. Birdsfoot trefoil. p. 98-108. In Maurice E.
Heath, Robert F. Barnes, and Darrel S. Metcalfe 4‘“ ed. Forages the Science of
Grassland Agg'gulture. Iowa State University Press, Ames, Iowa.

45

Griffin, T.S., O.B. Hesterman, and SR. Rust. 1991. Effect of alfalfa maturity and
cultivar on ip si_tp escape protein. NC-189 Proc. AFCG, Saint Louis,
Missouri. 1 Oct-30 Sept. 1991. Michigan State University, East Lansing, MI.

Hesterman, O.B., R. H. Leep, and J. Paling. 1989. Alfalfa variety tests.
(unpublished). Central alfalfa improvement conference report. Michigan Agr.
Exp. Stat., East Lansing, MI.

Hesterman, O.B., H.F. Bucholtz, and MS. Allen. 1991. Forage quality: What is
it? Michigan State Univ. Coop. Ext. Serv. Bull. E—2292.

Howarth, R. E. 1988. Antiquality factors and non nutritive chemical components.
In Hanson A.A., D.K. Barnes, and RR. Hill 2‘“ ed. Alfalfa and Alfalfa
Improvement. ASA, CSSA, and SSSA, Madison, WI.

Jung, H.G. 1989. Forage lignins and their effects on fiber digestibility. Agron. J.
81:33-38.

Kalu, EA. and G.W. Fick. 1981. Quantifying morphological development of alfalfa
for studies of herbage quality. Crop. Sci. 21: 267-271.

Kalu, B.A., and G.W. Fick. 1983. Morphological stage of development as a
predictor of alfalfa herbage quality. Crop. Sci. 23:1167-1172.

Kilcher, MR. and DH. Heinrichs. 1974. Contribution of stems and leaves to the
yield and nutrient level of irrigated alfalfa at different stages of development.
Can. J. Plant. Sci. 54:739-742.

Kuhbauch, W. and L. Pletl. 1981. Estimation of feed quality of white clover, red
clover, and lucerne using morphological criteria and/or chemical constituents of
plants. I. Reportzestimation of feed quality from stem length or from cell-wall
content of the stem. 2. Acker Pflanzenbase 150:271-280.

Latheef, M.A., J .L. Caddel, R.C. Berberet, and J.F. Stritzke. 1988. Alfalfa forage
yield, stand persistence, and weed colonization as influenced by variable first
harvest in Oklahoma. J. Prod. Agri. 1:155-159.

Leep, RH. and MB. Tesar. 1981. Growing birdsfoot trefoil in Michigan.
Michigan state University Coop. Ext. Ser. Bull. E1536, East Lansing, MI.

Leep, RH. and JR. Lempke. 1986. Birdsfoot trefoil variety evaluations in northern
Michigan. Research rep. 474 Agri. Exp. Stat., Michigan State University, East
Lansing, MI.

46

MacGraw, R.L., and G.C. Marten. 1986. Analysis of primary spring growth of
four pasture species. Agron. J. 78:704-710.

Marten, G.C. 1970. Temperature as a determinant of quality of alfalfa harvested by
bloom stage or age criteria. p. 506-509. In M.J.T. Norman (ed.) Proc. 11‘“ Int.
Grassl. Congr., Queensland, Australia.

Marten, G.C. and RM. Jordan. 1979. Substitution value of birdsfoot trefoil for
alfalfa-grass in pasture systems. Agron. J. 71:55-59.

Marten, G.C., D.R. Buxton, and RF. Barnes. 1988. Feeding value (Forage
quality). p. 463-491. In Hanson A.A., D.K. Barnes, and RR. Hill 2‘“ ed.
Alfalfa and Alfalfa Improvement. ASA, CSSA, and SSSA, Madison, WI.

Mehrez, AZ. and ER. Orskov. 1977. A study of the artificial fibre bag technique
for determining the digestibility of feeds in the rumen. J. Agric. Sci., Camb.
88:645-650.

Moline, W.J. and W.F. Wedin. 1969. Yield and quality evaluations of first-cutting
Vernal alfalfa. J. Sci. 43:261-273.

Mullahey, J.J., S.S. Waller, K.J. Moore, and LE. Moser. 1992. I_n m ruminal
protein degradation of swithchgrass and smooth bromegrass. Agron. J. 2:183-188.

Nelson, C.J. and D. Smith. 1968. Growth of birdsfoot trefoil. II. Morphological
development and dry matter distribution. Crop Sci. 8:21-25.

Nocek, J .E. 1988. 1a _si_tu and other methods to estimate ruminal protein and energy
digestibility: A review. J. Dairy Sci. 71:2051-5069.

Ohlson, Ch. and W. F. Wedin 1989. Phenological staging schemes for predicting red
clover quality. Crop Sci. 29: 416—420.

Onstad, D.W. and G.W. Fick. 1988. Statistical models for predicting alfalfa
herbage quality from morphological or weather data. J. Prod. Agric. 1:160—166.

Paling, 1.]. 1992. The effect of 3, 4, and 5 cuttings on alfalfa yield, persistence,
forage quality, and milk production. M.S. thesis. Michigan State University, East
Lansing, MI. (In press).

Rotar, RP. and A.E. Kretschmer. 1985. Tropical and subtropical forages. p. 154-
165. In Maurice E. Heat, Robert F. Barnes, and Darrel S. Metcalfe 4‘“ ed.
Forages the Science of Grassland Agriculture. Iowa State University Press, Ames,

Iowa.

47

Sanderson, M.A., J.S. Horstein, and W.F. Wedin. 1989. Alfalfa morphological
stage and its relation to i_n gtp digestibility of detergent fiber fractions of stems.
Crop. Sci. 29:1315-1319.

Sanderson, M.A., M. A. and W. F. Wedin. 1988. Cell wall composition of alfalfa
stems at similar morphological stages and chronological age during spring growth
and summer regrowth. Crop Sci. 28:342-347.

Sanderson, M.A., M. A. and W. F. Wedin. 1989. Phenological stage and herbage
quality relationships in temperate grasses and legumes. Agron. J. 81:864-869.

SAS Institute. 1986. SAS user’s guide: statistics. SAS Institute, Cary, NC.

Sauer, W.C., H. Jorgensen, and R. Berzins. 1983. A modified bag technique for
determining apparent digestibilities of protein feedstuff for pigs. Can. J. Anim.
Sci. 63:233-237.

Sheaffer, C.C., G.D. Lacefield, and V.L. Marble. 1988. Cutting schedules and
stands. p. 411-437. In Hanson A.A., D.K. Barnes, and RR. Hill 2‘“ ed. Alfalfa
and Alfalfa Improvement. ASA, CSSA, and SSSA, Madison, WI.

Smith, Dale. 1962. Forage production of red clover and alfalfa under differential
cutting. Agron. J. 57:463-465.

Smith, Dale. 1962. Carbohydrate root reserves in alfalfa, red clover, and birdsfoot
trefoil under several management schedules. Crop Sci. 41 :244-251

Smith, Dale. 1965. Forage production of red clover and alfalfa under differential
cutting. Agron. J. 57:463-465.

Smith, Dale and C.J. Nelson. 1967. Growth of birdsfoot trefoil and alfalfa. 1.
Responses to height and frequency of cutting. Crop Sci. 7:130-133.

Smith, Dale. 1969. Influence of temperature on the yield and chemical composition
of ’Vernal’ alfalfa at first flower. Agronomy J. 61:470-472.

Smith, Dale. 1972. Cutting schedules and maintaining pure stands. In C.H.
Hanson (ed.) Alfalfa science and technology. Agronomy 15:481-496.

Smith, Dale.. 1981. Variations in the composition of forage. p. 197-207. In D.
Smith (ed.) Forage Management in the North. Kendall/Hunt Publishing Co. ,
Dubuque, IA.

48

Stem, MD. and C. Sergio. 1991. Measuring protein degradability and intestinal
protein digestibility of feedstuffs. Proc. Minn. Nutr. Conf. 52:1-13. University
of Minnesota, Mn.

Taylor, N.L. 1985. Red clover. p. 109-117. In Maurice E. Heat, Robert F.
Barnes, and Darrel S. Metcalfe 4‘“ ed. Forages the Science of Grassland
Agg'culture. Iowa State University Press, Ames, Iowa.

Tesar, MB. 1970. Response of alfalfa to frequent cutting and variable dates of fall
cutting. Agron. Abstr. American Society of Agronomy, Madison, WI, p. 57.

Tesar, MB. 1978. Forage management. A notebook prepared for forage crops
courses at Michigan State University, East Lansing, MI.

Van Keuren, R.W. and CS. Hoveland. 1985. Clover management and utilization.
p. 326—348. In N .L. Taylor (ed.) no. 25 in Agronomy. Madison, Wisconsin,
USA.

Van Soest, P.J. 1965. Symposium on factors influencing the voluntary intake of
herbage by ruminants: Voluntary intake in relation to chemical composition and
digestibility. J. Animal Sci. 24:834-843.

Van Soest, P.J. 1967. Development of a comprehensive system of feed analysis and
its application to forages. J. Animal Sci. 26:119-128.

Van Soest, P.J. and RH. Wine. 1967. Use of detergents in the analysis of fibrous
feeds. IV. Determination of plant cell-wall constituents. In A.O.A.C. vol.
50(1):50-55.

Van Soest, P.J., D.R. Martens, and B. Deinum. 1978. Preharvest factors
influencing quality of conserved forage. J. Anim. Sci. 47:712-720.

Van Soest, P.J. 1982. Nutritional ecology of the ruminant. O&B, Corvallis, OR.

Walgenbach, RF. 1983. Autumn management of alfalfa affects forage yield,
quality, and persistence. p. 112-117. In Proc. Am. Grass. Counc., Eau Claire,
WI. 23-26 January. American Forage and Grassland Council, Lexington, KY.

Watkins, K.L., T.L. Venn, and GP. Krause. 1987. Total nitrogen determinations
of various sample types: A comparison of the Hack, Kjeltec, and Kjeldahl
methods. J. Assoc. Off. Anal. Chem. 70:410-412.

Weir, W.C., L.G. Jones, and James H. M. 1960. Effect of cutting interval and
stage of maturity on the digestibility and yield of alfalfa. J. Anim. Sci. 19:5-19.

49

Winch, J.E., R.W. Sheard, and D.N. Mowat. 1970. Determining cutting schedules
for maximum yield and quality of brome grass, timothy, lucerne, and
lucerne/grass mixtures. J. Br. Grassl. Soc. 25:44-52.

APPENDIX

50

Appendix Table A1. Growing degree days (GDD)1‘ for alfalfa, red clover, and
birdsfoot trefoil at early-, medium-, and late-cutting date during five harvest cycles in
1991 and 1992.

 

 

 

 

Cutting date Date GDD(°C)
1" Harvest cycle Early July 10 758
Medium July 19 768
Late July 31 870
2““ Harvest cycle Early August 13 1004
Medium August 22 1138
Late August 29 1303
3" Harvest cycle Early May 15 84
Medium May 26 203
Late June 6 309
4‘“ Harvest cycle Early July 1 412
Medium July 9 514
Late July 18 635
5‘“ Harvest cycle Early August 10 870
Medium August 19 938
Late August 28 967

 

TGDD=((maximum daily temperature86 oF +minirnum daily temperature50 °F)/2)-50
°F. Growing degree days in “F was converted to °C using the formula: °C=5/9(°F-
32). Growing degree days is cumulative from 1 April 1991 and from 1 April 1992.

 

51

Appendix Table A2. Mean stage by weight (MSW)? for alfalfa, red clover, and
birdsfoot trefoil at early-, medium-, and late-cutting date for five harvest cycles in
1991 and 1992.

 

 

 

 

 

Species
Cutting date Alfalfa Red clover Trefoil
#

1“ Harvest cycle

Early 1.7 1.0 1.6
Medium 4.7 1.5 2.3
Late 4.0 1.6 3.3
2'" Harvest cycle

Early 2.5 1.4 2.0
Medium 3.8 1.5 1.8
Late 3.0 2.7 2.9
3‘“ Harvest cycle

Early 1.5 1.0 1.0
Medium 2.8 1.3 3.1
Late 3.0 1.7 3.0
4‘“ Harvest cycle

Early 2.3 1.0 1.6
Medium 3.5 2.6 3.7
Late 5.0 2.8 4.1
5‘“ Harvest cycle

Early 2.3 1.0 1.0
Medium 2.9 1.4 1.2
Late 4.2 1.6 1.5

 

TFor alfalfa, the Kalu and Fick’s mean stage by weight system was used. For red
clover and birdsfoot trefoil, the MSW system described earlier in the Material and
Method section of this thesis was used.

52

Appendix Table A3. Linear and quadratic regression equations and r2 values of dry
matter (DM) yield, neutral detergent fiber (N DF), acid detergent fiber (ADF), crude

protein (CP), and escape protein (EP) concentrations of alfalfa, red clover, and

birdsfoot trefoil regressed on growing degree days (GDD) for five harvest cycles in

 

 

1991 and 1992.

Species Variables Equations? r2

Alfalfa

Linear DM DM = 22.58 +0.0008(GDD):[: 0.29
CP CP=28.21+0.0015(GDD) 0.02
ADF ADF=36.65 +0.0021(GDD) 0.57
NDF NDF = 6.76 +0.0002(GDD) 0.57
EP EP=5.68+00015(GDD) 0.28

Quadratic DM DM=23.12-0.0019+(GDD)+0.00001(GDD2) 0.48
CP CP=28.50+0.0001(GDD)-0.00001(GDD2) 0.02
ADF ADF = 34.29 +0.0138(GDD)-0.01379(GDD2) 0.08
N DF N DF = 8.60-0.0001(GDD)-0.55666(GDD2) 0.57
EP EP=5.03 +0.0041(GDD)-0.00001(GDD2) 0.33

Red clover

Linear DM DM=22.41+0.0010(GDD) 0.35
CP CP=23.50+0.0021(GDD) 0.04
ADF ADF=33.54+0.0004(GDD) 0.003
NDF NDF=7.19+0.0007(GDD) 0.06
EP EP = 3 .08 +0.0027(GDD) 0.24

Quadratic DM DM = 22. 87-0.0012(GDD) + 0.000002(GDD2) 0.45
CP CP = 23 .02 +0.0045(GDD)-0.000009(GDD2) 0.04
ADF ADF=31.37+0.0112(GDD)-0.000009(GDD2) 0.16
NDF NDF = 8.50 +0.0004(GDD)—0.040216(GDD2) 0.29
EP EP = 2.95 + 0.0032(GDD)-0.0000004(GDD“) 0.24

 

TAll equations were not significant at P 50.05 level. All linear regression equation
calculations were based on 13 d.f. All quadratic equation calculations were based on

12 d.f.

iGDD=((maximum daily temperature86 °F+minimum daily temperatures0 °F)/2)-50
°F. Growing degree days on °F was converted to °C using the formula: °C=5/9(°F-

32).

53
[Appendix Table A3 (con’t)].

 

 

Species Variables EquationsT r2

Birdsfoot trefoil

Linear DM DM = 22.30 +0.0010(GDD)$ 0. 34
CP CP=27.41-0.0015(GDD) 0.06
ADF ADF = 35 . 52-0.0010(GDD) 0.02
NDF NDF=6.31+0.0010(GDD) 0.21
EP EP=5.26+0.0018(GDD) 0.19

Quadratic DM DM =22.84-0.0008(GDD) +0.001013(GDD2) 0.40
CP CP = 29 .72—0.0095(GDD) +0.000005(GDD2) 0. 15
ADF ADF = 37. 89-0.0091(GDD) +0.000006(GDD2) 0.08
NDF NDF = 8.99 +0.0001(GDD)-0.733747(GDD2) 0.57
EP EP = 3 .56 +0.0087(GDD)-0.000005(GDD2) 0.38

 

TAll equations were not significant at P5005 level. All linear regression equation
calculations were based on 13 d.f. All quadratic equation calculations were based on
12 d.f.

:l:GDD=((maximum daily temperature86 °F+minimum daily temperature50 °F)/2)-50
°F. Growing degree days on “F was converted to °C using the formula: °C=5/9(°F-
32).

54

Appendix Table A4. Linear and quadratic regression equations and r2 values of dry
matter (DM) yield, neutral detergent fiber (N DF), acid detergent fiber (ADF), crude

protein (CP), and escape protein (EP) concentrations of alfalfa, red clover, and

birdsfoot trefoil regressed on mean stage by weight (MSW) for five harvest cycles in

 

 

1991 and 1992 .

Species Variables Equationsl' r“:

Alfalfa

Lineari DM DM=1.74+0.3916(MSW) 0.18
CP CP=23.11+0.0039(MSW) 0.001
ADF ADF = 24.23 +1.5434(MSW) 0.21
NDF NDF = 30.63 +2. 3768(MSW) 0.44
EP EP=5.45+0.4288(MSW) 0.19

Quadratic DM DM = -0. 83 +2. 1230(MSW) + 2. 12300(MSW2) 0.27
CP CP=22.97+0.1014(MSW)-0.01487(MSW2) 0.005
ADF ADF = 10.02 +11.1264(MSW)-l.46200(MSW2) 0.08
NDF NDF = 8.60—0.0001(MSW)-0. 55665(GDD2) 0.42
EP EP=5.03 +0.7117(MSW)-0.04315(MSW) 0.19

Red clover

Linear CP CP = 23 .25-0.0792(MSW) 0.008

Quadratic DM DM =-3. 14-3.142(MSW)-1.49550(MSW2) 0.43
CP CP=21.80+1.682(MSW)-0.46417(MSW2) 0.06
ADF ADF=5.99+19.60901(MSW)-4.22773(MSVV2) 0.63
NDF NDF = 24. 82 + 7.98382(MSW)-1 .26664(MS\V2) 0.29
EP EP=-0.51+4.67955(MSW)-0.71965(MSW2) 0.47

Birdsfoot trefoil

Linear CP CP =23 .49-0. 18587CMSW) 0.09
EP EP=4.99+0.70959(MSW) 0.21

Quadratic DM DM = -0.47 +2.09390(MSW)-0.26164(MSW2) 0.58
CP CP = 22.79 +0. 50702(MSW)-0. 14536(MSW2) 0. 13
ADF ADF = 17.95 + 5 . 70068(MSW)-0.74951(MSW2) 0.43
NDF NDF = 22 .66 + 7 . 85723 (MSW)-0. 97591(MSW2) 0. 71
EP EP=5.21+0.049237(MSW)+0.04557(MSW) 0.21

 

TAll linear regression equation calculations were based on 13 d.f. All quadratic
regression equation calculations were based on 12 d.f.
:tAll equations are not significant, P 50.05.

55

.52 883 .53 Siege: .53.. 215m a 255 data: :3 8"qu ..=;
HHEBBE ..=: _Hbcem a. £96 zeta: 6:3 onafi .552 cNHEeEo—z :32 flux—Hem ”m 298 58.55 twee. managed
twe< NNHEEBE ..m=< flux—58 ”N 298 585m 32. finned..— .._:_. Eugen—€02 ..=—p. Sum—Em A 298 emote=+

 

 

 

 

 

 

 

 

«.5 8.9. 4.8 o.«« an em a: 5.8 c.«« «.m 3 5.3. ”.8 «.8 3 33
3. «.8 8.8 «.8 3m 5. 5.8 5.8 «.8 an E 5.8 «.8 2.8 3. 5282
«.5 m8 5.8 5.8 o.« «.« won 58 «.8 3 3. n: 5.8 «.8 c.« 55
lasts: am

«.8 3m 88 5.8 In as 5.8 4.8 m8 3 E. 5.8 5.8 5.8 3 33
no a: 58 «.8 e.« 3 5.8 4.8 08 e.« «.w «.8 2.8 58 e.« .582
3 men 4.8 «.8 2 no ”.8 «.8 n8 w.« 5.5 «.8 n8 n8 5 ram
“mug: in

no «.8 8.8 08 em 58 is 5.8 08 ...m «.w 5.9. 58 08 a.« 23
w.» 88 n8 08 w.« 3 5.8 58 5.8 m.« 2 28 4.8 5.8 m.« 5:502
5.5 ”.8 w.«« m8 3 «.m 5.8 n.«« 5.8 M: «.« 08 n8 «.8 «.« ram
.6 do a i..- 295 5 -..: «Em: 50.5 a l..- So do 5 «a»: do? 5... ...... So do a i... new: lease: ..l_
5m "52 an? do 25 5m "52 59.. do 25 mm "52 53. 50 Sn as. 5:55

:85: 8885 585 Ba file?
5158.5.

 

55$ one 32 5 5.83.8 emote: can com 38 wage
-82 peeraaeoa [£58 8 =89: Seem—En dds ..8>o_o 52 .533 no 825855358 Ems $385 0588 pea .38 £885
835 55$ see 5858 28 .5525 5E 58558 :58: .255 :28 5:5: be .5 885 .5 use. .2 ”38 588%

56

.w:< wNflBfi ..w=< Eunice: ..w:< Subs ”m 298 55253 3:... wfiflafi :3».
“"8332 ..=: “Hz—55m ”v 2950 559:5: 6:2. onaj $52 anEEBE $52 flux—«am “m £98 538$ ”.wfix manofiq
..w=< NNHEEBE ..m:< Sum—.550 ”N 298 5035—.” 33. _muuumq :3». EHEBBE ..=—H 5:an a £93 555Em+

 

 

 

 

 

 

 

 

«.5 5.5« 5.«« 5.«« 5.« 5.« 5.5« 5.5« 5.«« 5.« «.5 5.: «.8 «.8 5.« 33
5.5 5.5« «.8 5.«« 5._ 5.« «.5« 5.«« «.8 5.« 5.5 «.5« 5.5« 5.«« 5.« 52552
5.« 5.5« 5.5« 5.«« «.5 5.« 5.5« «.5« 5.8 «.5 «.5 5.«« 5.5« 5.«« 5.5 «Em
“mug: an

5.« «.5« 5.5« «.8 5.« E «.5 5.5« 5.«« «.« 5.« 5.: 5.5« 5.«« 5.« 23
5.5 «.5« 5.5« 5.«« 5.« «.5 5.5« «.5« 5.«« 5.« 5.5 5.5« «.5« «.8 5.« 55552
«.5 5.«« «.5« 5.«« 5.« 5.« «.5« 5.«« 5.5« 5.« «.5 5.5« 5.«« 5.«« 5.« «Em
85.5 2555:... «£52 50555 £29555; «£52 50555 $2955.! «552 18.55....
mm ”52 59.. .6 2m 5m "52 "5.« mo 2m 5m "52 .552 50 Sn 555 «55:6

5555 58555 llldawm g?
535on

 

5.585 2 258. 55555555

57

55< 833 .53. Snags: .53 55ub5m 5 555 55555 555 fines :55
flung—€02 ..=—m "Hm—Em ”v 2950 “magi 6:3. oHSwA .5552 canaavuz $52 flux—55m “m 298 565m ”53‘ omuaj

..w:< Snag—502 ..w=< mdflbfio ”N 293 505$ 33 Qua—J ..=; Evin—=52 ..=—m Subs J 293 5553535
63855 0935: 05 .8 2Q 50 Enema 55 595—355 DEA—m1.

 

 

 

 

 

 

 

 

 

55 55 «5 55 5 55 55 55 5 555 5550
55 55 55 55 55 55 55 55 5 555555.355
55 55 5 55 5 55 «5 55 55 3:5
55 55 55 «5 55 55 55 55 5 5.555%
55 55 «5 55 «5 55 55 55 «5 3
55 55 «5 55 5 55 55 55 55 5555555155

55
33 5582 55m 33 85552 555 33 85552 5.5m
5555 585555 5.65 555 lea?
555 5553\ng

 

.82 5:5 83 E 5298 550% gm 5.5 855 $553.35— 555 $8338 .4258
5 5555 585555 5.5 .555 5a .5555 5 552955 55555555 5555 55 3'5 5 5 555 5 555.5 .55. 5555 555555.

58

Appendix Table A7. Correlation coefficients of dry matter (DM) yield, neutral
detergent fiber (NDF), acid detergent fiber (ADF), crude protein (CP), and escape
protein (EP) concentrations of alfalfa, red clover, and birdsfoot trefoil at five harvest

cycles in 1991 and 1992.

 

 

 

 

PM
Species/parameters NDF ADF CP EP
Alfalfa
DM yield (Mg/ha) 0.85* 0.81* -0.19 -0.01
NDF (%DM) 082* -0.10 0.40
ADF (%DM) -0.25 0.07
CP (%DM) 0.03
Red clover
DM yield (Mg/ha) 068* 0.77* -0.29 0.35
NDF (%DM) 0.81* -0.39 056*
ADF (%DM) -0.15 0.73*
CP (%DM) 0.20
M11.
DM yield (Mg/ha) 0.74* 0.64* -0.46 0.07
NDF (%DM) 093* -0.45 0.34
ADF (%DM) -0.48 0.18
CP (%DM) 0.10

 

*Significant correlation, P5005.

59

Appendix Table A8. Dry matter (DM) yield and crude protein (CP) yield total over a
two-year study for three legume species (alfalfa, red clover, and birdsfoot trefoil) at
three cutting datesT (early-, medium-, and late-).

 

 

 

 

 

Species
Alfalfa Red clover Trefoil

Mg/ha
DM yield
Early 10.0a 8.5al 9.1a
Medium 15.8b 13.6b 13.9"
Late 18.2c 17.7c 18.1c
C.V. 8.0 8.7 5.2
Chield
Early 2.3a 1.9a 2.0a
Medium 3.4b 3.4b 3.2b
Late 4.2c 4.0c 4.2c
C.V. 13.3 10.4 5.8

 

TEarly cutting date: 10 July and 13 August 1991 and 15 May, 1 July and 10 August
1992; medium cutting date: 19 July and 22 August 1991 and 26 May, 9 July, and 19
August 1992; late cutting date: 31 July and 29 August 1991 and 6 June, 18 July, and
28 August 1992.

abcNumbers within column followed by the same letter are not significantly different
(P5005).

"‘ltltulllillllwiilit