Effects of dietary fat and season on steroid hormonal profiles before parturition and on hormonal, cholesterol, triglycerides, follicular patterns, and postpartum reproduction in Brahman cows

被引：0

作者：

Lammoglia, MA ^{[1
]}

Willard, ST ^{[1
]}

Oldham, JR ^{[1
]}

Randel, RD ^{[1
]}

机构：

[1] TEXAS AGR EXPTL STN,OVERTON,TX 75684

来源：

JOURNAL OF ANIMAL SCIENCE | 1996年 / 74卷 / 09期

关键词：

cows; dietary fat; follicles; postpartum; season;

D O I：

暂无

中图分类号：

S8 [畜牧、动物医学、狩猎、蚕、蜂];

学科分类号：

0905 ;

摘要：

Spring-calving Brahman cows (S) artificially inseminated to Brahman, Angus, or Tuli sires and fall-calving Brahman cows (F) naturally bred to Brahman were allotted randomly to receive 3.74% (LF; n = 9 S and 6 F), 5.20% (MF; n = 8 S and 6 Fl, or 6.55% dietary fat (HF; n = 8 S). Diets were formulated to contain differing fatty acid concentrations and to be isocaloric and isonitrogenous. Cows were bled and fed twice daily from 2 wk before expected calving date through d 21 after calving. Ultrasonography was performed on d 14 and 21 after calving. From d 21 to 90 after calving a sterile bull equipped with a chin-ball marker was placed with the cows to aid in estrus detection. In both seasons progesterone decreased (P < .01) and estradiol-17 beta increased (P < .01) as parturition approached. Cows receiving MF and HF had increased (P < .01) total numbers of follicles compared to LF cows, and cows receiving MF had larger (P < .01) follicles. During the spring, cows receiving HF and cows bred to Brahman or Tuli sires had longer (P < .01) gestation lengths. Progesterone concentrations before calving were affected (P < .01) by treatment x sire and estradiol-17 beta by a time x treatment interaction (P < .01). Cholesterol after calving was higher (P <.01) in HF cows than in LF or MF cows. In the fall, LF cows had heavier (P <.01) calves than cows receiving MF. Birth weight was also affected (P <.01) by treatment x sex of calf. Progesterone was affected (P <.01) by treatment x sex of calf. Estradiol-17 beta was affected (P < .01) by sex of calf and treatment x sex of calf. Across seasons, by d 90 after calving, 9 of 15 (60%) LF and 11 of 15 (73.3%) MF cows showed estrual behavior. Cows in the spring had increased (P < .01) numbers and larger follicles compared to the fall. In conclusion, dietary fat may influence steroid hormone concentrations before calving, calf birth weight and postpartum follicular populations; furthermore, follicular populations may also be influenced by season.

引用

页码：2253 / 2262

页数：10