Resumen

ZARATE-MARTINEZ, Juan Prisciliano; RAMIREZ-GODINEZ, José Alejandro  y  RODRIGUEZ-ALMEIDA, Felipe Alonso. Comportamiento reproductivo de vacas criollas con amamantamiento restringido y sincronización del estro. Agron. Mesoam [online]. 2010, vol.21, n.1, pp.121-130. ISSN 2215-3608.

Reproductive performance of Creole cows with restricted suckling and estrus synchronization. The objectives were to study the reproductive performance, initiation of post-partum ovarian activity, response to restricted suckling, estrus synchronization, and conception rate using artificial insemination at a fixed time of Creole rodeo cows (C). In Chihuahua, México, during the summer 2008, twenty-seven cows were used over 95 d, and the beginning of post-partum ovarian activity was detected by ultrasonography. Hormone treatment for estrus synchronization was administered to 22 cows (n=11 per group). In treatment1 (T1) the cows (n=11) received a CIDR with 1,9 g of progesterone and one IM injection with 1 mg of β-estradiol + 50 mg of P₄. The CIDR was removed after d 7 and an IM injection of 30 mg of PGF_2α was applie d. After 24 h, 1 mg of β-estradiol was applied, and the cows were inseminated 54 h after removing the CIDR. T2 (n=11) was similar, but the IM injection contained β-estradiol only. The C showed aggressive behavior (AB) during the restricted suckling. The average days from the beginning of the ovarian activity were 11,66 d and only 11,11% of the cows exhibited estrus during initial ovarian activity. One hundred percent of the animals underwent estrus on d 9 post synchronization, there were not differences (P>0,05) among the levels of progesterone of the T1 (4,94±0,331 ng/ml) vs the T2 (4,87±0,30 ng/ml. There was a T*DS interaction for concentrations of progesterone and E₂ (P=0.06). There were no differences (P>0.05) in conception rate (18,8%). Adding P4 with a CIDR did not increase the levels of progesterone in C.

Palabras clave : Bovine; progesterone; estradiol; corpora lutea.

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