Acute reduction in serum progesterone concentrations after feed intake in dairy cows.

摘要: Abstract This study tested the hypothesis that high feed consumption will acutely decrease circulating progesterone concentrations. In first experiment, a Latin Square design was used to test whether feeding pattern would alter in pregnant lactating Holstein cows ( n =12). Feed removed for 12h before experiment and were then either fed 100% of total mixed ration (TMR), 50% TMR every 12h, 25% 6h, or left unfed an additional 12h. Blood samples taken hour 24h. Provision 100 decreased by 1h after remained depressed until 8–9h feeding. Feeding did not reduce Experiment 2 crossover measure effect acute on LH concentrations during delivery constant amount exogenous (Eazi-Breed CIDRs) =8) nonpregnant dry =6). 15min 8h. There no change serum 8h treatment period cows; however, P =0.01) than nonlactating cows. Thus, reduced apparently due increase metabolism. Interestingly, multiple smaller meals eliminated progesterone.