Presynchronization with prostaglandin F2α and gonadotropin-releasing hormone simultaneously improved first-service pregnancy per artificial insemination in lactating Holstein cows compared with Presynch-14 when combined with detection of estrus

• DOI: 10.3168/jds.2022-22651
• Publication Date: 2023-05-08T19:21:14Z
• Authors: J.P.N. Martins; T.O. Cunha; W. Martinez; J.S. Schmitt
• Keywords: fertility; 04 agricultural and veterinary sciences; SF250.5-275; Dinoprost; detection of estrus; Gonadotropin-Releasing Hormone; Dairying; SF221-250; Estrus; Pregnancy; Animals; Lactation; Female; Cattle; Ovsynch; Estrus Synchronization; 0405 other agricultural sciences; timed artificial insemination; Progesterone; Insemination, Artificial; presynchronization; Dairy processing. Dairy products

This study aimed to determine the effect of 2 simple breeding strategies combining artificial insemination (AI) after detection estrus (AIED) and timed AI (TAI) on first-service fertility in lactating Holstein cows. Weekly, cows (n = l,049) between 40 46 d milk (DIM) were randomly assigned initiate 1 for first service: Presynch-14 PG+G. is a presynchronization strategy with PGF2α treatments 14 apart last before initiation Ovsynch protocol. Cows treated PG+G receive simpler program that uses GnRH simultaneously 7 Ovsynch. In both treatments, detected standing by tail chalk at any time ≥55 DIM inseminated, treatment was discontinued 525). completing received TAI from 78 84 526). subgroup TAI, blood collected 163) assess circulating concentrations progesterone, ultrasonographic evaluations ovaries performed day 162) 122). The proportion greater compared (63.5 vs. 31.9%), which increased service (75.5 ± 0.4 68.7 0.4). For receiving ovulatory response (73.8 48.8%) functional corpora lutea (92.6 73.1%) than Presynch-14. had overall pregnancy per (P/AI) 42 (40.2 33.6%) calving (32.1 25.2%) AIED, did not affect P/AI AI. However, (44.6 35.2%). Overall, (42.5 31.5%) (34.1 23.7%) decreased loss (16.8 AIED. summary, service, P/AI, when programs combined