Indian Journal of Science and Technology
Year: 2018, Volume: 11, Issue: 19, Pages: 1-7
Emílio Pereira de Brito Neto1 , Rafael Otero2 , Darwin Hernández2*, Eduardo Paulino da Costa1 and Ademir Moraes Ferreira3
1 Universidade Federal de Viçosa, Viçosa - MG, 36570-900, Brasil; [email protected], [email protected],
2 Universidad de Sucre, Campus Ciencias Agropecuarias, Sincelejo, Sucre, Colombia; [email protected], [email protected]
3 Embrapa Gado de Leite, Juiz de Fora - MG, 36038-330, Brasil; [email protected]
*Author for correspondence
Universidad de Sucre, Campus Ciencias Agropecuarias, Sincelejo, Sucre, Colombia; [email protected]
Objective: This study was conducted to evaluate the effect of the follicular diameter upon gestation rate of cows submitted to Artificial Insemination at Fixed Time (IATF). Methods: Forty-seven crossbred cows Bos taurus x indicus presenting cyclical luteal ovarian activity and under nursing were used. The cows were given 150µg of PGF2α via Intra-Muscular (IM). The diameter of the present largest follicle was measured through Ultra-Sound Examination (USE). After 24 hours, the cows were given 2µg of estradiol via IM and they were again evaluated through USE for certification of the follicular dominance. Later, they were divided into two treatments: treatment 1 (cows with dominant follicle <13mm) and treatment 2 (cows with dominant follicle ≥13mm). After 48 hours from the application of E2 , the cows were Artificially Inseminated (AI). However, those cows presenting estrus in advance were inseminated at 12 hours after manifestation of the same one. Ten days after AI the concentration of progesterone (P4) was quantified by radioimmunoassay using a commercial kit. The gestation diagnosis was accomplished at 30 and 100 days after IA through USE. Findings: Differences (p<0.05) were observed in the gestation rates, that is 76% and 45.5% for animals of the treatments 1 and 2, respectively. The serum concentrations of P4 were 1.34±0.49 and 2.16±1.17 for the treatments 1 and 2 respectively (p<0.01). A low correlation (r=0.45) was observed between P4 levels and the presentation of pregnancy. Application: Cows with dominant follicles <13 mm in diameter at the time of application E2 have a higher gestation rate even with lower production of P4.
Keywords: Cows, Gestation, Reproductive Biotechnology, Reproduction
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