170 Embryonic loss and pregnancy rate in response to resynchronisation using oestradiol benzoate or injectable progesterone at 14 days after timed AI in Bos taurus×Bos indicus beef heifers

• DOI: 10.1071/rdv32n2ab170
• Publication Date: 2019-12-02T13:58:17Z
• Authors: C. C. Vieira; V. Buss; A. M. Oliveira; M. E. R. Costa; B. G. Freitas; G. A. Pessoa; F. G. Leivas; B. M. Guerreiro; G. Pugliesi; F. S. Mesquita
• Keywords: Equine chorionic gonadotropin; Cloprostenol; Beef Cattle

The effect of the exposure pregnant cattle to oestradiol benzoate (EB) or injectable long-acting progesterone (iP4), as well their use for early resynchronisation non-pregnant (NP) females within second week after timed AI (TAI), is yet be assessed. This study aimed assess pregnancy rate and embryonic loss cross-bred Bos taurus×Bos indicus beef heifers in response an EB- iP4-based strategy implemented 14 days first TAI. A total 677 cyclic (Braford Brangus; 24 months old) were subjected EB/P4 synchronisation protocol TAI (Day 0=TAI). On Day 14, all received a new P4 intravaginal device (1g, Sincrogest, Ourofino Saúde Animal) randomly assigned two groups: EB (1mg intramuscularly, Sincrodiol; n=339) iP4 (75 mg Sincrogest Injetável; n=338). 22, devices removed underwent colour Doppler ultrasonography evaluation. Non-pregnant identified by assessment structural regression corpus luteum, previously reported our group. NP 1mg cipionate (SincroCP), 250µg sodium cloprostenol (Sincrocio), 200IU equine chorionic gonadotrophin (SincroeCG), they inseminated on 24. diameter preovulatory follicle (POF) was also recorded. Pregnancy diagnosed via B-mode Days 35-40 54. Statistical analyses performed using SAS software (ver. 9.2, Institute Inc.). MIXED procedure used evaluate POF diameter, GLIMMIX develop multivariate model including treatment, breed, age, farm (1-7), possible interactions treatment with farm, age binomial data (pregnancy rates loss). In heifers, 22 did not differ (P>0.05) between (9.77±0.25mm) (9.92±0.22 mm) groups. Exposure post-TAI influence assessed (56.3% (191/339) vs. 60.1% (203/338)) (49.6% (168/339) 53.3% (180/338)). addition, different (12%, 23/191) (11.3%, 23/203) other hand, submitted greater (P=0.01) group (45.95%, 68/148) than (31.85%, 43/135). conclusion, improved can achieved associated without affecting loss. However, further investigation warranted lower obtained association device. research supported FAPESP (2015/10606-9; 2019/15514-6), Graduate Studies Support Program (PAPG-UNIPAMPA), Animal.