Agrotecnio Centre; University of Lleida, 25198 Lleida, Spain.
Transfer in Bovine Reproduction SLu, 22300 Barbastro, Spain.
J Reprod Dev. 2021 Apr 21;67(2):135-139. doi: 10.1262/jrd.2020-144. Epub 2021 Feb 15.
Since the 1970s, luteolytic doses used for synchronizing estrus in dairy cattle have remained unchanged. This study aimed to evaluate the dose-response effect of prostaglandin F (PGF), which is used for synchronizing estrus, and subsequent fertility in cows with two or more corpora lutea (CL). The study population consisted of 1,683 cows with a single CL (1CL), 501 cows with multiple CL receiving a single dose of PGF (2CL1), and 252 cows with multiple CL receiving a 1.5 × PGF dose (2CL1.5). Cows with a single CL (n = 1,245) showed estrus significantly (P < 0.01) earlier (3.01 ± 1.23 days; mean ± SD) than cows with multiple CL (n = 287; 3.33 ± 1.69 days). Using 1CL cows as reference, the odds ratio (OR) for the estrus response in 2CL1 cows was 0.13 (P < 0.0001), whereas the ORs for estrus response and pregnancy of 2CL1.5 cows were 1.8 (P = 0.0001) and 1.7 (P = 0.001), respectively. Based on the results for only the 2CL1 cows, the OR for the estrus response was 0.7 (P = 0.01) for cows producing ≥ 45 kg of milk at treatment, compared to the remaining cows producing < 45 kg of milk. Our results showed that the presence of multiple CL reduced the estrus response to that induced by a single PGF dose and milk production was inversely associated with this response, whereas an increased PGF dose improved the estrus response. Therefore, an increase in the standard PGF dose is recommended.
自 20 世纪 70 年代以来,用于奶牛同期发情的溶黄体剂量一直保持不变。本研究旨在评估前列腺素 F(PGF)在具有两个或更多黄体(CL)的奶牛中的剂量反应效应,用于同期发情和随后的生育能力。研究人群由 1683 头具有单个 CL(1CL)的奶牛、501 头接受单次 PGF 剂量的多 CL 奶牛(2CL1)和 252 头接受 1.5×PGF 剂量的多 CL 奶牛(2CL1.5)组成。具有单个 CL 的奶牛(n=1245)发情明显(P<0.01)早(3.01±1.23 天;平均值±SD)于具有多个 CL 的奶牛(n=287;3.33±1.69 天)。以 1CL 奶牛为参考,2CL1 奶牛的发情反应的优势比(OR)为 0.13(P<0.0001),而 2CL1.5 奶牛的发情反应和妊娠的 OR 分别为 1.8(P=0.0001)和 1.7(P=0.001)。仅基于 2CL1 奶牛的结果,与剩余产奶量<45kg 的奶牛相比,在处理时产奶量≥45kg 的奶牛发情反应的 OR 为 0.7(P=0.01)。我们的结果表明,多个 CL 的存在降低了对单个 PGF 剂量的发情反应,而产奶量与这种反应呈负相关,而增加 PGF 剂量则改善了发情反应。因此,建议增加标准 PGF 剂量。