Effects of corn and molasses supplements with and without feed additives on performance, voluntary intake, and digestive function in cattle fed bermudagrass hay

324 Pages·1996·10.3 MB·English

by  Balbuena, Osvaldo

EFFECTS OF CORN AND MOLASSES SUPPLEMENTS WITH AND WITHOUT FEED
ADDITIVES ON PERFORMANCE, VOLUNTARY INTAKE, AND DIGESTIVE
FUNCTION IN CATTLE FED BERMUDAGRASS HAY
By
OSVALDO BALBUENA
A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY
UNIVERSITY OF FLORIDA
,1
1
This dissertation is dedicated to my wife Elena for the
years of love, help, and encouragement and to my children
Gonzalo, Nicolas and Maria Daniela.
ACKNOWLEDGMENTS
I wish to express sincere gratitude to the supervisory
committee consisting of Drs. W.E. Kunkle, D.B. Bates, J.E.
Moore, A.C. Hammond, and L.E. Sollenberger. Special
gratitude is extended to Drs. Kunkle and G. Hembry for
financial support during the last six months of my project.
I am very thankful to the Institute Nacional de Tecnologia
Agropecuaria (INTA) for financial support during my first
thirty months at UP. Special thanks to the efforts of Jerry
Wasdin, Dan Price, the Pine Acres and Santa Fe crew, and
Dane Bernis (Feed Mill). Special thanks is extended to
Jeanette Filer and Angelita Mariano for their help in the
lab and during the experiments. I am in debt to John Funk,
Pamela Miles, and Nancy Wilkinson from Nutrition Lab and to
Sandra Armantrout and Christa Jenssen from Extension. I am
also in debt to E. Bowers from STARS-Brooksville, Drs. R.C.
Hill and K. Scott for allowing me to use their GC, and Dr.
C.H. Courtney and Qiyun Jeng for helping me with
parasitology analysis. I am very thankful to Kevin Downs,
Diane Campbell, and Francisco Olbrich for their help during
the experiments. I would also like to extend special thanks
to Diego Rochinotti for his friendship and help, and thanks
to Pedro Garces-Yepez for sharing his experience with me.
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TABLE OF CONTENTS
ACKNOWLEDGMENTS
ABSTRACT
CHAPTERS
1
I INTRODUCTION 1
II LITEI^TURE REVIEW 3
AInnttirboidoutcitcionFeed Additives in Ruminants .... 35
Mechanisms of Action 6
Importance of Gut Metabolism 12
Nonionophore Antibiotics 14
BambentiYcins 15
Ruminant Performance 17
Digestive Function 26
Post-ruminal Effects 31
Summary of Effects of Bamberm^cins 35
lonophore Antibiotics 36
Effects on Performance 38
lonophore Modes of Action 44
Ruminal effects 45
Total tract digestibility 52
Metabolism of the host animal 53
Animal health 56
Interaction with Minerals 57
Frequency of Feeding 60
Summary of Effects of lonophores 62
Considerations in Feeding Molasses 63
Digestive Function 64
Intake and Performance 77
Summary of Feeding Molasses 79
III EFFECT OF BAMBERMYCINS AND MONENSIN IN CORN
OR MOLASSES SUPPLEMENTS ON PERFORMANCE OF
GROWING CATTLE 82
Introduction 82
Materials and Methods 83
Results and Discussion 91
Animal Performance 93
Volatile Fatty Acids 113
iv
Plasma Urea Nitrogen 121
Parasites 123
IV EFFECTS OF BAMBERMYCINS FED IN CORN OR MOLASSES
SUPPLEMENTS ON INTAKE, DIGESTIBILITY, AND DIGESTION
KINETICS IN HEIFERS 125
Introduction 125
Materials and Methods 126
Results and Discussion 135
Pre-trial 136
LLaattiinn SSqquuaarree -- DIingteaksetioanndKDiniegteisctsibility . . 114398
V EFFECTS OF BAMBERMYCINS FED IN CORN OR MOLASSES
SUPPLEMENTS ON RUMEN FUNCTION 162
Introduction 162
Materials and Methods 163
Digesta Kinetics 164
Characteristics of Ruminal Fluid 167
Ruminal and Total Tract Digestion 168
ResNuilttrsogeanndFDliowscuasnsdioMnicrobial Efficiency . . 117730
Digesta Kinetics 175
Characteristics of Ruminal Fluid 181
Ruminal and Total Tract Digestion 204
Nitrogen Flow and Microbial Efficiency . . 220
VI SUMMARY AND CONCLUSIONS 233
EExxppeerriimmeenntt 21 -- AInnitmaakle aPnedrformance (Chapter III) . 233
Digestibility (Chapter IV) 237
Experiment 3 - Riomen Function and
Digestibility (Chapter V) 238
Conclusions 244
APPENDICES
A TABLES 247
B RAW DATA 256
LITERATURE CITED 286
BIOGRAPHICAL SKETCH 315
V
.
Abstract of Dissertation Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy
EFFECTS OF CORN AND MOLASSES SUPPLEMENTS WITH AND WITHOUT
FEED ADDITIVES ON PERFORMANCE, VOLUNTARY INTAKE, AND
DIGESTIVE FUNCTION IN CATTLE FED BERMUDAGRASS HAY
By
Osvaldo Balbuena
December, 1996
Chairperson: W.E. Kunkle
Major Department: Animal Science
lonophores and bambermycins have improved gain of
growing cattle fed forage based diets when mixed in grain or
mineral supplements. In limited research monensin has not
improved gain of growing cattle when fed in molasses based
liquid feeds offered at 2 kg/d or more and the efficacy of
bambermycins in this supplement has not been evaluated.
Growing cattle fed bermudagrass hay were supplemented
with 1.57 kg TDN from corn-urea (CU) or molasses-corn gluten
meal (MCG) without and with monensin or bamberirrycins
,
Cattle fed supplements without antibiotics gained .62 kg/d.
Monensin increased gain .035 kg/d in CU and decreased gain
.029 kg/d in MCG. Bambermycins increased gain .106 kg/d in
CU and .042 kg/d in MCG. Monensin decreased hay intake .14%
of BW while bambermycins increased hay intake .14% of BW in
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Year 1 and had no effect in Year 2, Monensin increased the
difference between observed and predicted gains (an
estimator of feed efficiency) .102 and .026 kg/d in CU and
MCG, while bambemrycins increased that difference .063 and
.041 kg/d in CU and MCG, respectively.
Effects of CU or MCG with and without bambermycins on
feed intake and digestive function were evaluated in two 4 x
4 Latin squares with ad libitum and restricted intake.
Bambennycins increased total DM intake .08% of BW but did
not affect digestibility. Bambennycins increased ruminal pH
(6.63 vs 6,52), decreased butyrate molar proportions (9.8 vs
10.6), and did not affect acetate:propionate ratio (C2:C3)
and microbial N efficiency. Ruminal pH, total VFA, VFA molar
proportions, and CjtCj exhibited a supplement by time
postfeeding interaction (P < .07). Steers fed CU had higher
(P < .033) apparent (3.59 vs 2.99 g N/100 g OM) and true
(2.47 vs 2.19 g N/100 g OM) microbial N efficiency, and
higher ruminal feed CP degradability (69.2 vs 58.9%) than
those fed MCG.
Monensin improved gain in cattle fed corn but did not
improve gain in cattle fed molasses supplement. Bambermycins
improved gain in cattle fed corn and molasses supplements
but this effect was greater in corn than in molasses.
Increased gain due to bambermycins was not explained by
changes in digestive function.
I
CHAPTER 1
INTRODUCTION
,
Warm-season grasses are the main feed resource for cow-
calf and backgrounding production systems. Animal production
based on warm season forages is usually lower than on
temperate forages because intake and nutritive value of C4
grasses is lower. Excess biomass production during the warm
and humid season is conserved as hay, haylage or stockpiled
forage to be used as the basal diet during the winter
months. High animal performance is not possible with this
feed resource alone because intake of digestible energy
often is only enough to meet maintenance requirements or
support low gains Supplemental feeds to meet animal
.
requirements for energy, protein, and minerals are
recommended in Florida. Feed additives that enhance animal
production and therefore improve the biological and
economical response to supplemental feeding are desirable.
Molasses is a locally available energy source competitively
priced compared to traditional feeds. Researchers at
University of Florida have evaluated high levels of molasses
supplementation with the addition of dry ingredients
containing natural protein sources (molasses slurries) An
.
effective feed additive to improve gain in cattle fed
1
.
2
molasses slurries at levels of 30 to 40% of the total diet
is not available. Limited research has suggested that
ionophores are not effective when fed in molasses slurries
but more evidence is necessary.
Objectives of this research are as follows:
1. Evaluate the efficacy of ionophore (monensin) and
nonionophore (bambermycins antibiotics to improve gain in
)
growing cattle fed high forage diets (bermudagrass hay)
supplemented with a corn- or molasses-based feeds.
2. Evaluate the effects of feeding bambermycins on
voluntary hay intake and digestive function of cattle fed
high forage diets supplemented with corn- or molasses-based
feeds.
3. Compare the digestive function in cattle fed high
forage-based diets supplemented with corn- or molasses-based
feeds
CHAPTER 2
LITERATURE REVIEW
Tntrodnrtion
Animal performance (growth, reproduction) is often
suboptimal when only warm-season forages are fed.
Consequently, some type of protein and(or) energy
supplementation is often needed. Molasses-based supplements
are often fed to cattle consuming warm-season forage diets.
Feed additives that enhance growth may improve biological
and economical response to supplementation.
Competitive feedstuffs are defined as those that can
also be used as human food, while complementary feedstuffs
are not used directly for human consumption. Rumsey (1984)
and Hammond (1991) discussed the noncompetitive nature of
ruminant production using the protein conversion ratio
(Table 2-1). Relative input/output for ruminant protein is
less efficient than protein produced by nonruminant animals.
However, the use of competitive feedstuffs inputs is lower
in ruminant production systems. The advantage of ruminants
is the use of complementary feeds. The challenge is,
therefore, to increase the animal output using
noncompetitive feeds.
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