Table Of ContentUSE OF BOVINE SOMATOTROPIN (BST) IN MANAGEMENT OF GROWING
HEIFERS AND TRANSITION COWS TO IMPROVE GROWTH RATES AND MILK
PRODUCTION
ALFREDO N. GARCIA GAVIDIA
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
1998
To the memory ofmy parents Alejandro Garcia and Aminta Gavidia de Garcia.
To my children Ahraham, Manuel and Indira Garcia Mattos and specially to my wife Elsa
Mattos de Garcia, who has givento me all the emotional support I have needed to be here
working toward this goal.
ACKNOWLEDGMENTS
I would like to thank my professors for all the help I have received from them,
especiallythose who have been members ofmy Ph.D. committee, Dr. H. Herbert Head as
chairman, and Dr. Charles J. Wilcox, Dr. John E. Moore, Dr. Douglas B. Bates and Dr.
Ramon C. Littell.
Special recognition goes to Ms. Joyce Hayen, our laboratory chemist, who has
givento me all the help I have needed as a son.
1 thank Dr. Mary Beth Hall, Dr. Roger West, Dr. William Thatcher and Dr.
Charles Staples fortheir support during this research.
thank Mary Ellen Hissem and Helen Hester for their friendship.
I
1 thank all the persormel from the DRU, especially Mr. Dale Hissem, James
Lindsey, Charlene Roomes, Joe Cline, Robert Tillman, Mary Russell, Helen Lindsey,
Elese Griffin and others.
I thank my friends Rafael Roman, Diego Rochinotti, John Kobera, Amelia
Luengo, Thais Diaz, Tomas I. Belloso, Andres Kowalski, Elide Valencia, Carlos
Arechiga, Oswaldo Rosendo, Maria Eugeniia Cadario, Antonio Landaeta, Carlos Vargas,
Victor Monterroso, Mario Binelli, Morgan Pletier, David Feitsma, Mehmet Gulay, Alice
Moraes, JenniferTrout and all my classmates who have shared with me during all this
time. Finally, I acknowledge all those persons who, in one way or another, have helped
me.
Ill
TABLE OF CONTENTS
ACKNOWLEDGMENTS
iii
ABSTRACT
vii
CHAPTERS
INTRODUCTION
1 1
2 MILK PRODUCTION OF FIRST CALF HEIFERS RAISED ON TWO
PLANES OF NUTRITION AND INJECTED WITH BST
7
Introduction 7
Body Growth, Puberty and Mammary Gland Development 9
Growth Rates, Age at Calving and Milk Yield 13
Somatotropin, Growth and Mammary Gland Development 18
Materials and Methods 23
Experiment I 24
Animals 24
Experimental design 24
Injections ofbST 25
Feeding 25
Animal measurements 26
Statistical analyses 28
Experiment II 29
Animals 29
Experimental design 30
Injections ofbST 31
Feeding 31
Animal measurements 32
Milking and sampling 34
Statistical analyses 34
Results and Discussion 35
Conclusions 63
t
IV
3 EFFECT OF NUTRITIONAL STATUS AND PREPARTUM AND
POSTPARTUM BST TREATMENTS ON DRY MATTER INTAKE,
ENERGY STATUS, BODY WEIGHT CHANGE AND MILK YIELD
OF DAIRY COWS DURING EARLY LACTATION
64
Introduction 64
Dry Matter and Energy Intake During the Transition Period 65
Diet and Intake the During Transition Period 68
Body Condition Score and Transition Period 75
Energy Status and Metabolism During the Transition Period 79
Mechanism ofMetabolic Regulation During the Transition Period .... 83
Materials and Methods 88
Experimental Animals 88
Injections ofbST 93
Feeding Program 94
Data Collection 94
Feed intake 94
Body weight and body condition score 95
Milk samples 95
Blood samples 95
Net energy intake and energy status 96
Statistical Analyses 97
Results and Diseussion 98
Dry Matter Intake, Energy Status, and Changes in Body Weight
and Body Condition 103
Milk Yield, 4% FCM and Milk Constituents 123
Conclusions 134
4 EFFECTS OF NUTRITIONAL STATUS AND PREPARTUM AND
POSTPARTUM BST TREATMENT ON METABOLIC HORMONES
AND OVARIAN ACTIVITY OF DAIRY COWS DURING EARLY
LACTATION
136
Introduction 136
Insulin, Somatotropin and Insulin-like Growth Factor-I 137
Somatotropin, IGF-I and Ovarian Activity 143
Other Metabolic Hormones 147
Materials and Methods 149
Insulin Assay 151
Prolactin Assay 154
Insulin-like Growth Factor I (IGF-I) Extraction and Assay 157
Somatotropin Assay 161
Triiodothyronine Assay 164
V
Thyroxine Assay 165
Statistical Analyses 167
Results and Discussion 168
Conclusions 189
GENERAL CONCLUSIONS
5 190
APPENDIX
194
REFERENCES
198
BIOGRAPHICAL SKETCH
222
VI
Abstract ofDissertation Presented to the Graduate School
ofthe University ofFlorida in Partial Fulfillment ofthe
Requirements for the Degree Doctor ofPhilosophy
USE OF BOVINE SOMATOTROPIN (BST) IN MANAGEMENT OF GROWING
HEIFERS AND TRANSITION COWS TO IMPROVE GROWTH RATES AND MILK
PRODUCTION
By
Alfredo N. Garcia Gavidia
May 1998
Chairperson: H. Herbert Head
Major Department: Dairy and Poultry Sciences
Milk production of 194 Holstein heifers was evaluated for effects ofplane of
nutrition during the growth period from 90 to 365 d and bST injections (12.36 mg/d or
500 mg/14 d) from 220 to 365 d ofage. Two groups ofHolstein heifers were utilized
(I = 63 II =183 heifers). Heifers were fed either alfalfa silage or com silage plus grain
;
concentrates. Actual or 305-d and total milk yield records were used in the analyses.
Models included bST, diet, season ofcalving, year ofcalving, age at calving, calving
weight, DIM, DO ADG, and appropriate interactions. The ADG from 220 to 365 d time
,
period when bST was injected, was significantly and positively associated withthe milk
yield (P< 0.0208). Effects ofDIM, DO and season ofcalving were significant. The mean
yields were 6841 (n= 52) and 7024 (n= 56) kg/305-d for heifers on control and high
vix
energy diets without bST 7006 (n= 36) and 7076 (n= 27) kg/305-d for heifers fed
;
control and high energy diets plus 35.7 mg bST/d; and 6706 (n= 9) and 6860 (n= 14)
kg/305-d for heifers on control and high energy diets plus 12.6 mg bST/d. Heifers raised
on different planes ofnutrition injected or not with bST during the peripubertal period
produced the same amount ofmilk during the first lactation. The second study included
48 Holstein cows to evaluate prepartum and postpartum treatments ofbST and nutrition
status on DMI, energy status, milk yield, some metabolic hormones and progesterone (P4)
during early postpartum period. Treatments were arranged in a 2x2x2 factorial and
included prepartum injections ofbST (0 and 5 mg/d), postpartum injections ofbST (0 and
%
5 mg/d), and diet (0 and 15 WCS). Models included the main effect oftreatments and
the two- and three-way interactions oftreatments. Prepartum bST treatment resulted in
higher concentrations ofST, IGF-I and glucose before parturition. Prepartum and
postpartum bST treatment resulted in increased DMI (P <0.0281), slightly higher milk
yield, improved energy status (P < 0.1038) and increased concentrations ofST and IGF-I
during early postpartum period.
Vltl«l•
CHAPTER
1
INTRODUCTION
One ofthe first biotechnology derived products available for use in animal
production is Bovine Somatotropin (bST). In contrast to steroids, bST is a protein
hormone. Many investigations have demonstrated milk yield and lactation persistency
responses to bST for all breeds ofdairy animals examined. However, quality of
management apparently is amajor factor affecting magnitude ofmilk response to bST.
Productive efficiency ofdairy cows has been defined as the yield ofmilk and milk
components relative to the nutritional cost ofmaintenance, lactation, and the return ofthe
cowto the level ofbody condition that existed before onset ofthe lactation.
On the other hand, dairy farmers must invest capital, time and feed in orderto
raise replacements for their dairy herds. Raising heifer replacements will increase
profitability when it can be accomplished more efficiently with reduced costs. One way
to decrease the cost ofraising replacements is by decreasing the time forthem to reach
first parturition. A major factorthat affects age at first calving is the limited capacity of
heifers to partition nutrients when attempts are made to increase their growth rates.
Possible effects ofthis limited capacity are on development ofmammary epithelial tissue
or accretion ofbody protein, both ofwhich are important but remain secondary to
partitioning ofnutrients for more rapid grov^h (Hoffman and Funk, 1992).
1
2
The heifer raising program may be a separate enterprise on a dairy farm but it is
likely that it would be an integral part ofdairy operations. Advanced age at first
I
parturition usually is considered to be detrimental for dairy profit because ofincreased
labor and feed costs and delayed income from sale ofmilk (Lin et al., 1988). It has been
recommended that replacement dairy heifers reach first parturition at about 22- 24 mo of
age and at least 550 to 560 kg oflive weight after calving (NRC, 1989; VandeHaar,
1998). These recommendations are largely based upon the positive correlations between
size at first calving and milk production.
Growth ofdairy heifers has been described as a natural expansion process such
that the heifer increases in external size in all directions at a rather uniform but not
constant rate (Brody, 1945). Growth ofdairy heifers is affected by many factors
including genetics, nutrition, health and management. Maturation ofthe reproductive
system occurs along with an increase in body weight and size (Brody, 1945).
Traditionally, for cattle, weight has been used as the measurement unit that is
representative ofanimal size. However, skeletal measurements in conjunction with body
weight may be better indicators ofan animal's size (Heinrichs and Hargrove, 1987, 1991;
Swanson et al., 1967).
Many years ofresearch have resulted in recommendations for growth ofdairy
heifers during the prepubertal and postpubertal growth periods. Because research has
shown the economic benefits offirst parturition between 22-24 mo ofage, it is necessary
to evaluate various alternatives offeeding and management ofdairy heifers that will
allow the farmerto achieve these target body weights at first calving. Several
