Influence of fat supplementation on postpartum reproductive performance in Brahman cows
Date
1996
Journal Title
Journal ISSN
Volume Title
Publisher
Texas A&M University
Abstract
Multiparous Brahman cows (n=40) in excellent body condition (6.45 [] 0.12) were randomly assigned to receive either a fat-added (rice bran, 5.18 % EE) or a no fat-added (control, 3.74 % EE) supplement after calving. The experimental diets were formulated to be isocaloric and isonitrogenous. Cows were weighed, scored for body condition, and bled at weekly intervals from day 1 through day 50 after calving. Weekly breedings of the cows continued until the first detectable estrus. Thereafter, daily blood samples were collected throughout the first normal estrous cycle. Cows showing abnormal estrous cycle length continued to be bled until a first normal estrous cycle was completed. Ovarian follicular populations were recorded weekly by transrectal uftrasonography from days 14 to 49 after calving. A final ultrasound was performed on day 12 of the first normal estrous cycle to verify the presence of a CL and register follicular populations once normal cyclic activity had resumed. Calf weights were recorded at 14 day intervals from days 1 to 43 after birth and at weaning (205 days). Fat supplemented cows gained more body condition (Day x Treatment, P<0.05) than cows receiving the control supplement. The numbers of small (< 4.0 mm; Treatment, P<0.05), medium (4.0 to 7.9 mm; Day x Treatment, P<0.05) and total follicles (Treatment, P<0.05) were increased in fat supplemented cows during the early postpartum period (14 to 29 days after calving), while large follicles L> 8.0 mm) increased in number (P<.05) and the largest follicle increased in size (P4.001) across time regardless of the level of dietary fat. Fat supplementation also increased the numbers of medium (P<0.01), large (P<0.05), and total (P<,O.Ol) follicles as well as the size of the largest follicle (P<0.05) from weeks 3 to 1 prior to the first normal estrous cycle. Similar follicular populations (P>0.10) were observed between dietary treatments once normal ovarian cycles had resumed. The intervals from parturition to reproductively important endpoints were similar between dietary treatments as well as the percentage of cows showing normal or abnormal estrous cyclic activity. Daily serum P4 concentrations were not influenced (P>0.10) by treatment. However, there was a tendency (P=0.09) for more nice bran supplemented cows to be pregnant after being exposed to a fertile bull. Enhanced calf performance was observed in calves nursed by fat supplemented cows possibly due to a stimulatory effect of dietary fat on milk production. In conclusion, using dm bran as a fat supplement for multiparous postpartum Brahman cows enhanced follicular growth causing the development of smaller sized follicles into ovulatory sized follicles before normal ovarian cycles resumed. Dietary fat also increased body condition scores, pregnancy rates, and calf weights without altering postpartum interval or serum P4 concentrations.
Description
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Includes bibliographical references.
Issued also on microfiche from Lange Micrographics.
Includes bibliographical references.
Issued also on microfiche from Lange Micrographics.
Keywords
physiology of reproduction., Major physiology of reproduction.