info:eu-repo/semantics/article
Effect of GnRH and D-Chloprostenol application on pregnancy and prolificacy rates on Pelibuey ewes
Autor
Martínez T, Jaime
Montañez V, Oziel
Ley De C, Alejandro
Izaguirre F, Fernando
Velazco Z, María
Aguirre M, Juan
Institución
Resumen
ABSTRACTObjective. Was to evaluate the effect of GnRH and D-Chloprostenol application on pregnancy and prolificacy rates on Pelibuey ewes. Materials and methods. Forty five ewes were randomly allocated to one of three treatments: T1(n=15), day 0: sponges with 65 mg medroxyprogesterone acetate (MPA) + 200 IU equine chorionic gonadotropin (eCG) and sponge removal (day 12) + breeding by natural mating (days 12-15); T2 (n=15), day 0: 50 μg gonadotropin releasing hormone (GnRH) + 7.5 mg D-Chloprostenol (day 5) + 50 μg GnRH (day 7) + insemination at fixed time (AIFT) 12 to 14 h after last injection of GnRH; T3 (n=15), 100 μg GnRH (day 0) + 7.5 mg D-Chloprostenol (day 5) + 100 μg GnRH (day 7) + AIFT 12 to 14 h after last injection of GnRH. Results. The average concentration of progesterone (P4) in blood was 1.22 ± 0.74 ng/mL, which was used to verify ovarian activity at the beginning of the treatments. 100% of the T1 ewes presented estrus, beginning at 38.4±9.56 h after sponge removal. There were differences (p<0.05) for pregnancy rates, of 60, 33.33 and 46.66% respectively, among the treatments. Prolificacy was no different (p>0.05) among the treatments where the values were 1.2, 1.4 and 1.4 lambs/ewe for T1, T2 and T3, Conclusions. The results of this study show that the use of GnRH and D-Chloprostenol did improve pregnancy rates but did not improve prolificacy in tropical ewes