Pregnancy Rate of Bunaji Cows in a Fixed Time AI Synchronization Protocol Using Ovatide

Abstract

This study accessed the reproductive performance of Bunaji cows in an Ovsynch protocol involving ovatide. Bunaji cows (n = 16) aged 4-6 years and weighing between 250-350 kg with body condition scores (BCS) of 2.5-3.5 were used. There were two treatment groups for synchronization of ovulation. Treatment group 1 comprising Bunaji (n = 8) received 50 µg of gonadotropin releasing hormone (GnRH) (Cystorelin) and 25 mg of PGF 2α. While, treatment group 2 comprising Bunaji (n = 8) received 50 µg of ovatide and 25 mg of PGF 2α. All cows from both treatment groups were inseminated at 16 h after each second GnRH or ovatide injections. Cows that showed mucus discharge from the vagina on the day of artificial insemination (AI) were recorded as well as those that had patent cervix. Cervical dilation was measured by taking note of the cows that had mid cervix insemination due to non-passage of the AI gun through the cervix. Transrectal palpation was conducted twice at a month interval to select cycling cows within 5-12 d of the estrous cycle before initiating Ovsynch protocol. It was repeated on day 45 post AI to confirm pregnancies in animals. Results showed that the rate of mucus discharge from the vagina was 37.5% and 87.5% for ovatide and Cystorelin, respectively; while the rate of cervical dilation were 75% and 87.5% for ovatide and Cystorelin, respectively (p > 0.05), and pregnancy rates were 0% and 12.5% for ovatide and Cystorelin, respectively. There were no significant differences between the two groups. It was concluded that treatment of Bunaji cows with 50 µg ovatide in Ovsynh protocol has heat and ovulation synchronization potentials and zero pregnancy rate. It was recommended that further studies be carried out using graded doses of 50, 100 and 150 µg of ovatide in a fixed time AI synchronization protocol in Bunaji cows, to tap the potentials of the hormone in manipulation of bovine reproduction.

A utilização de GnRH ou Galectina-1 no momento da IA aumenta a taxa de concepção em vacas de corte submetidas a IATF?

“…Na presente pesquisa, a administração de GnRH ocorreu em todos os animais do experimento, não sendo verificado tamanho do folículo dominante, nem presença ou ausência de estro. De forma semelhante, Azubuike et al, (2019) observaram índices de prenhez superiores a 52% quando utilizaram estas estratégias em planos de IATF em bovinos da raça Bunaji, criados na Nigéria.…”