Fertility programs for lactating dairy cows: A novel presynch + timed artificial insemination program (Double E-Synch) produces similar ovarian dynamics, synchronization, and fertility as Double-Ovsynch

• Published in: Journal of dairy science Vol. 108; no. 4; pp. 4435 - 4447
• Main Authors: Consentini, Carlos E.C., Abadia, Tattiany, Galindez, Juan P.A., Lopes, Ana L.M., Ferro, Pedro P.C., Pazini, Yasmim E., Faria, Natalia V., Machado, Fernando, Capella, Tuanne, dos Santos, Tiago N., Duarte, Marcelo, Ferreira, Paulo P., Matos, Luiz M.F., Ferreira, Danilo R., Campos, Ernane, Prata, Alexandre, Melo, Leonardo F., Wiltbank, Milo C., Sartori, Roberto
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.04.2025; Elsevier
• Subjects: acetates; Animals; artificial insemination; Cattle; cloprostenol; corpus luteum; dairy cow; dairy science; estradiol; estrus; Estrus Synchronization - methods; Female; fertility; Fertility - drug effects; Gonadotropin-Releasing Hormone - administration & dosage; Insemination, Artificial - methods; Insemination, Artificial - veterinary; Lactation; Ovary - drug effects; Ovary - physiology; ovulation; Pregnancy; progesterone; Progesterone - administration & dosage; Progesterone - pharmacology; synchronization; timed artificial insemination; synchronization; dairy cow; timed artificial insemination; fertility
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.2024-25221

Fertility programs were implemented for the first postpartum timed artificial insemination (TAI) in 800 (primiparous and multiparous) lactating dairy cows, evaluating 2 presynchronization (presynch) strategies and 2 TAI protocols, in a 2 × 2 factorial arrangement. Weekly, cows were enrolled into 1 of 4 groups (Ovs+Ovs [Double-Ovsynch], Ovs+OvsP4/E2, PreP4/E2+Ovs, and PreP4/E2+OvsP4/E2 [Double E-Synch]). On d −17 (34 ± 3 DIM), the Ovsynch [Ovs] presynch was initiated with 10 µg of buserelin acetate (GnRH), and cows received 0.5 mg of cloprostenol sodium PGF2α analog (PGF) on d −10, and 10 µg of GnRH on d −7. The PreP4/E2 presynch was initiated on d −17 with a used 2-g progesterone (P4) insert, which was removed on d −10, together with 0.5 mg of PGF and 1 mg of estradiol (E2) cypionate (EC). For TAI protocols, Ovs group received the following: on d 0, 20 µg of GnRH (double dose); on d 7, PGF; on d 8, PGF; on d 9.5, 10 µg of GnRH; and on d 10, TAI (16 h after GnRH). Cows submitted to OvsP4/E2 received the following: on d 0, 20 µg of GnRH (double dose) and a new 2-g P4 insert; on d 7, PGF; on d 8, P4 insert removal, PGF, and EC; and on d 10, TAI (48 h after P4 insert removal). The GLIMMIX procedure of SAS 9.4 was used for statistical analyses (P ≤ 0.05). The presence of corpus luteum (CL) on d −17 (average = 68.8% [550/800]) was similar among treatments. The presence of CL on d 0 of TAI protocols was high, and Ovs as a presynch increased percentage of cows with CL (95.5% [382/400] vs. 90.8% [363/400]). However, at the first PGF of the breeding (TAI) protocols (d 7), there was no effect of presynchronization program and 98.5% (788/800) of the cows had at least 1 CL. Ovulation after d 0 was greater in cows submitted to PreP4/E2 than Ovs (72.0% [288/400] vs. 64.3% [257/400]), and those ovulating had greater pregnancies per artificial insemination (P/AI; 51.0% [278/545] vs. 41.6% [106/255]). Overall, multiple ovulations after TAI were low and similar between TAI protocols and presynch strategies (7.2% [54/753]). Expression of estrus in OvsP4/E2 protocols was greater than Ovs (69.4% [274/395] vs. 41.5% [168/405]), and an interaction was detected, in which cows not expressing estrus ovulated more after TAI in Ovs compared with OvsP4/E2 protocol (93.3 [221/237] vs. 77.7% [94/121]). Cows expressing estrus had greater P/AI in both Ovs (58.3 [98/168] vs. 42.2% [100/237]) and OvsP4/E2 (57.3 [157/274] vs. 24.0% [29/121]). There was no interaction between presynch and TAI protocol on P/AI on d 32 of cows that ovulated after TAI (48.4%, 49.7%, 53.3%, and 52.5% for Ovs+Ovs, Ovs+OvsP4/E2, PreP4/E2+Ovs, and PreP4/E2+OvsP4/E2, respectively), and no differences in pregnancy loss between d 32 and 90 (average = 24.0% [92/384]). In conclusion, the study validated 2 presynchronization strategies and 2 TAI protocols, establishing 4 possible fertility programs, all of them producing well-controlled ovarian dynamics, excellent synchronization, and high fertility. Moreover, Double-Ovsynch and Double E-Synch both produced similar results, despite differences in pharmacological bases. The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. [Display omitted]