Veterinarski arhiv, Vol. 86 No. 3, 2016.
Izvorni znanstveni članak
Comparison of equine chorionic gonadotropin (eCG) and oestradiol cypionate administered 24 h after CIDR removal during an oestrus synchronization protocol for artificial insemination in Mexican Criollo cattle.
Andrés Quezada-Casasola
; Programa de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Ciudad Juárez, Anillo envolvente y Estocolmo, Ciudad Juárez, Chihuahua, México
Linda V. Beltrán-Prieto
; Facultad de Zootecnia y Ecología, Universidad Autónoma de Chihuahua, Chihuahua, Chihuahua, México
Ulises Macías-Cruz
; Instituto de Ciencias Agrícolas, Universidad Autónoma de Baja California, Ejido Nuevo León, Baja California, México
Leonel Avendaño-Reyes
; Instituto de Ciencias Agrícolas, Universidad Autónoma de Baja California, Ejido Nuevo León, Baja California, México
José A. Ramírez-Godínez
; Facultad de Zootecnia y Ecología, Universidad Autónoma de Chihuahua, Chihuahua, Chihuahua, México
Sažetak
Two experiments were conducted to evaluate the effect of administering equine chorionic gonadotropin (eCG) in substitution of estradiol, 24 h after the removal of a progesterone intravaginal device, on estrus and ovulatory response, and pregnancy rates of Rodeo Criollo cows (exp. 1, n = 21) and heifers (exp. 2, n = 39) subjected to a synchronization protocol (estradiol + CIDR + PGF2α) with estrus-detected artificial insemination. All females were inseminated 12 h after detected estrus. In cows, estrus and ovulation response, and maximum pre-ovulatory follicle diameter were similar (P>0.05) between equine chorionic gonadotropin and estradiol groups. However, the time to estrus was shorter (P<0.05) with estradiol, but equine chorionic gonadotropin increased (P<0.05) the estrus and ovulation grouping, as well as pregnancy rates. In heifers, estradiol increased (P<0.05) estrus response and reduced (P<0.05) time to estrus, without any difference (P>0.05) in ovulation rate. Both treatments resulted in low pregnancy rates, with a significantly lower (P<0.05) rate in heifers treated with equine chorionic gonadotropin. In conclusion, application of equine chorionic gonadotropin in substitution of estradiol, after the removal of a progesterone-releasing device in an estrus-detected AI protocol, increased the estrus and ovulation grouping and, consequently, pregnancy rate in cows, but not in heifers.
Ključne riječi
native cattle; estrus synchronization; equine chorionic gonadotropin
Hrčak ID:
161535
URI
Datum izdavanja:
10.6.2016.
Posjeta: 1.090 *