Effect of ovulation synchronization with Ovsynch program on reproductive performance and blood parameters in Holstein cows

Abstract

This study was undertaken to investigate the effect Ovsynch program on reproductive performance, plasma progesterone concentrations and some blood biochemical parameters of Holstein cows subjected and non-subjected to OvSynch protocol. The study involved 20 cows divided randomly into two groups. The cows within the first group were subjected to OvSynch protocol, received 10µ/ cow GnRH injection at day 1, followed by an injection of 500µ/ cow PGF2α i.m. at day 8 and second GnRH injection (10µ/ cow) at day 10. The cows were artificially inseminated, 18-24 hours later. Simultaneously, the cows in the second group were injected only with normal saline solution at similar days (placebo group) and artificially inseminated following detection of estrus. Blood samples (10 ml) were collected via jugular venipuncture from all cows at days 1, 8 and 10 of OvSynch protocol for plasma progesterone assay and some blood biochemical parameters measurements. Pregnancy were detected using plasma progesterone concentrations and ultrasonography at days 35, 45 and 60 PM and by rectal palpation at days 45 and 60 PM. The T1 group had higher (P<0.05) conception and pregnancy rates than T2 group (50 vs. 40%). Greater (P<0.05) progesterone concentration was observed following first GnRH injection (day 8) of cows subjected to OvSynch protocol and declined (P<0.05) after PGF2α injection (day 10). Higher (P<0.05) plasma glucose concentrations were noticed at day 8 as compared with day 10 in cows subjected to OvSynch protocol. Plasma cholesterol, triglycerides and very low density lipoproteins were significantly (P<0.05) increased at day 10 in comparison with day 8 in cows subjected to OvSynch protocol. It can be concluded that OvSynch protocol as an economic tool for estrus synchronization application may enhanced conception and pregnancy rates without negative influences on blood biochemical parameters of Holstein cows