تاثیر نمره وضعیت بدن در زمان زایش بر راندمان تولیدمثلی پس از زایش در گاوهای شیری

Background: metabolic status of animal at calving time is influenced on postpartum reproductive performance. objectives: the objective of this study was to investigate the effect of body condition score (bcs) at calving on postpartum reproductive performance in dairy cows. methods: fourteen dairy cows were assigned into two equal thin (bcs < 2.5) and fat (bcs?3) groups, based on their body condition score at calving. body weight (bw) and bcs were measured every other week, starting from two weeks before calving till pregnancy confirmation. rectal palpation was performed weekly to evaluate uterus status and also presence or absent of corpus luteum on ovaries, starting a week after calving. in order to study of interrelationship between bcs and some blood parameters with reproductive traits bleeding was performed every other week. results: least squares means (±se) of blood plasma concentrations of estrogen (pg/ml) for thin and fat cows were 90.6±3 and 37.4±11 and of progesterone (ng/ml) 1.5±0.3 and 6.6±3.0, respectively. blood plasma concentrations of insulin, glucose, urea, total cholesterol and triglyceride were similar in thin and fat cows. mean (±se) uterus returning time (37±6.9 vs. 26.4±3.5 days), time of first ovulation (54.2±6 vs. 37.5±5.2 days) and interval from calving to first service (95.0±14 vs. 67.5±12 days) was significantly greater for thin cows. conception rate in thin and fat cows were 71.4 and 85.7, respectively. correlation between bcs with estrogen and progesterone were -0.7 and -0.35, respectively. in addition, correlation between bcs and reproductive parameters was negative. conclusions: this study showed that bcs at calving affects postpartum reproductive performance