Animal and Veterinary Science, University of Idaho, Moscow, Idaho 83844, USA.
Statistical Programs, University of Idaho, Moscow, Idaho 84844, USA.
Anim Reprod Sci. 2020 Jan;212:106253. doi: 10.1016/j.anireprosci.2019.106253. Epub 2019 Nov 26.
Embryonic loss in cattle may be related to a hormonal imbalance resulting in alterations in timing of prostaglandin F (PGF) secretion around the time of maternal recognition of pregnancy. The objective of this study was to examine effects of aspirin (a PGF inhibitor) on pregnancy per AI (P/AI), and progesterone (P), and pregnancy specific protein B (PSPB) concentrations in lactating dairy cows inseminated more than once after parturition. Fourteen days after second or subsequent AI (Day 0 = Day of AI), 556 cows were assigned randomly to aspirin (187.2 g total; n = 277) or control (n = 279) groups. Aspirin was administered orally on Day 14 and 15, and control cows were subjected to sham bolus administration. On Day 25, blood samples were collected from a subset of cows (n = 194) to quantify P and PSPB, whereas pregnancy was determined in all cows at 35-42 days post-AI. Maximum daily ambient temperature ranged from 38-41 °C during the experiment. Mean parity, days in milk, and times bred before treatment (TBRD) did not differ between groups. There were no differences in P/AI between treatments (aspirin 21.6 % compared with control 27.5 %). Neither treatment, parity, TBRD, or any two-way interactions with treatment affected concentrations of P. Moreover, there were no effects (P > 0.50) of treatment, or treatment by TBRD interaction on serum PSPB concentrations. A tendency (P = 0.07) occurred for multiparous cows to have greater serum PSPB concentrations compared with primiparous cows. Mean serum PSPB concentrations tended (P = 0.07) to be greater for second or third TBRD compared to fourth and greater TBRD. These results provide evidence that aspirin administered during periods of heat stress after the second and subsequent AI post-partum during the summer months does not improve P/AI or alter P and PSPB in lactating dairy cows.
牛的胚胎丢失可能与激素失衡有关，导致妊娠识别后前列腺素 F（PGF）分泌的时间发生变化。本研究的目的是研究阿司匹林（PGF 抑制剂）对产奶奶牛多次配种后的妊娠率（P/AI）、孕酮（P）和妊娠特异性蛋白 B（PSPB）浓度的影响。产后第二次或多次配种后 14 天（第 0 天=配种日），将 556 头奶牛随机分为阿司匹林（187.2g 总量；n=277）或对照组（n=279）。阿司匹林于第 14 天和第 15 天口服给药，对照组接受假冲击给药。第 25 天，从一部分奶牛（n=194）采集血样以定量检测 P 和 PSPB，而所有奶牛均在配种后 35-42 天进行妊娠检测。实验期间，环境日最高温度范围为 38-41°C。两组间的平均胎次、产奶天数和配种前的配种次数（TBRD）无差异。处理组之间的 P/AI 没有差异（阿司匹林组 21.6%，对照组 27.5%）。处理、胎次、TBRD 或两者与处理的任何双向相互作用均未影响 P 的浓度。此外，处理或处理与 TBRD 相互作用对血清 PSPB 浓度均无影响（P>0.50）。多胎奶牛的血清 PSPB 浓度高于初产奶牛，有增加的趋势（P=0.07）。与第四次及以后的 TBRD 相比，第二次或第三次 TBRD 的血清 PSPB 浓度有增加的趋势（P=0.07）。这些结果表明，在夏季产犊后第二次和随后的 AI 期间，在热应激期间给予阿司匹林并不能提高 P/AI，也不能改变产奶奶牛的 P 和 PSPB。
