The effect of administration of combined-GnRH and PGF 2 α and organic zinc on crossbred cow fertility.

The objective of this study was to evaluate the administration of a combination of GnRH, PGF 2 α, and organic zinc on crossbred cow fertility. Twenty-four crossbred cows (LimPO/SimPO) were allotted into four different treatments: A: GnRH, PGF 2 alfa injection and zinc methionine (ZnMeth), B: GnRH injection and ZnMeth, C: PGF 2α injection and ZnMeth, and D: ZnMeth as control. The GnRH was injected at 5 ml/head and PGF 2 α was intramuscularly injected at 2 ml/head, ZnMeth was offered at 3 g/head/day for 63 days. Plasma samples were collected on days 0, 21,42, and 63. The mating system was artificial insemination (AI). The pregnancy was examined two months after AI. The data were analyzed using analysis of variance (ANOVA) using SPSS version 23. The results showed that the body condition score was not different between treatments (p>0.05), A: 7.08±0.15 (32.32%), B: 7.25±0.11 (32.78%), C: 7.08±0.83 (40.38%) and D: 7.33±0.17 (34.59%). The concentration of estrogen (17.52–43.09 ng/mL) and progesterone (5.72–20.88 ng/ml) were not different between treatments (P>0,05). The D group had the lowest libido rate than other groups; the percentage of conception rates were 16.67%, 16.67%, 0%, and 0% respectively; while the pregnancy rates for A, B, C, and D were 66.67%, 50%, 33.33%, and 0% respectively. Thus, the combination of GnRH and PGF 2 α in crossbred cows resulted in a higher pregnancy rate than a group receiving only ZnMeth. It was concluded that a combination of GnRH, PGF 2 α, and ZnMeth treatments improved the reproductive performance of cows and the pregnancy rate reached 66.67%. [ABSTRACT FROM AUTHOR]