Effect of GnRH at Estrus and 12-Day Post Matting and Propylene Glycol on Sera Metabolites Concentrations and Ewe Conception Rate
Published on: 2018-06-28
In this study GnRH and propylene glycol respectively used as hormonal treatment and to supply precursor material of glucose. Animals (56 crossbred ewes, Arkhamerino-Ghezel (AG) and Arkhamerino-Moghani (AM), 2.5 years old) were classified to 1 control and 3 treatment groups randomly. After estrus detection and before mating, one milliliter of physiological saline (0.9% NaCl, placebo) was administered to each ewe in control group, group 1 were injected with 2.5 ml GnRH and after 2 hours they were mated by ram, group 2 were injected with 5 ml GnRH 12 days after mating, group 3 were received 30 ml propylene glycol for 5 days after mating. Blood samples were taken on 6 d after mating by using vacuum tube. Glucose, urea, phosphorus, total protein, β-hydroxybutyrate (BHBA) and progesterone concentrations in blood serum were measured. Results shows that glucose in AM was significantly higher than AG (P<0.01). Urea and BHBA in AM were significantly (P<0.01) lower than AG. In repeat breeder ewes, progesterone concentration in estrus 2 was significantly (P<0.05) higher than estrus 1, and urea and BHBA concentrations in estrus 2 were significantly (P<0.05) lower than estrus 1. Administration 5 ml of GnRH on day-12 after mating was effective on reproductive performance than others. In conclusion, results showed that only one sheep in GnRH-2.5 ml treatment at estrus and five sheep in GnRH-5 ml on day-12 after mating showed repeat estrus and suggested that using 2.5 ml of GnRH before mating had better effect to prevent of repeat breeder.