School of Veterinary Medicine and Animal Science, Sao Paulo State University (UNESP), Botucatu 18168-000, Brazil.
Department of Animal Science, Texas A&M University, College Station, TX 77843-2471, USA.
Anim Reprod Sci. 2022 Aug;243:107028. doi: 10.1016/j.anireprosci.2022.107028. Epub 2022 Jun 18.
This experiment evaluated pregnancy rates to fixed-time artificial insemination (FTAI) in Bos indicus beef cows according to their body condition score (BCS) at calving and subsequent change until 30 days after FTAI. Non-pregnant, suckling Nelore cows (n = 593 primiparous, 461 secundiparous, and 893 multiparous) were evaluated for BCS at calving and FTAI, and at 30 days after FTAI when cow pregnancy status was verified. Cow BCS at calving was subtracted from BCS recorded at pregnancy diagnosis, and cows classified as those that lost BCS (L), maintained BCS (M), or gained BCS (G) during this period. Cows that calved with BCS ≥ 5.0 had greater (P < 0.01) BCS throughout the experiment, and greater (P < 0.01) pregnancy rates to FTAI compared with cows that calved with BCS < 5.0 (54.8 vs. 34.2%). Pregnancy rates to FTAI were greater (P < 0.01) for G and M cows compared with L cows (50.0%, 47.5%, and 36.0%, respectively), and similar (P = 0.46) between G and M cows. Moreover, pregnancy rates to FTAI in G cows that calved with BCS < 5.0 were less compared with L (tendency; P = 0.08) and M cows (P < 0.01) that calved with BCS ≥ 5.0 (42.2%, 48.3%, and 58.3%, respectively). In summary, pregnancy rates to FTAI were greater in B. indicus cows that calved with a BCS ≥ 5.0 regardless of parity and post-calving BCS change, and greater in M and G cows within those that calved with BCS < 5.0 or ≥ 5.0.
本试验评估了根据产犊时体况评分（BCS）和随后至固定时间人工授精（FTAI）后 30 天的变化，对婆罗门瘤牛的妊娠率。非妊娠、哺乳期内罗尔牛（n=593 头初产，461 头经产，893 头多产）在产犊时和 FTAI 时进行 BCS 评估，并在 FTAI 后 30 天妊娠状态得到验证时进行评估。从妊娠诊断时记录的 BCS 中减去产犊时的 BCS，将牛分为在这段时间内失去 BCS（L）、保持 BCS（M）或获得 BCS（G）的牛。BCS≥5.0 的牛在整个试验中具有更高的 BCS（P<0.01），且与 BCS<5.0 的牛相比，FTAI 的妊娠率更高（54.8%对 34.2%）。与 L 牛相比，G 和 M 牛的 FTAI 妊娠率更高（P<0.01）（50.0%、47.5%和 36.0%），G 和 M 牛之间没有差异（P=0.46）。此外，与 L 牛（倾向；P=0.08）和 M 牛（P<0.01）相比，BCS<5.0 产犊的 G 牛的 FTAI 妊娠率较低，BCS≥5.0 产犊的 L 牛和 M 牛分别为 42.2%、48.3%和 58.3%。总之，BCS≥5.0 产犊的婆罗门瘤牛的 FTAI 妊娠率更高，与胎次和产后 BCS 变化无关，而 BCS<5.0 或≥5.0 产犊的 M 和 G 牛的妊娠率更高。
