Effect of Flushed Feeding and Age on Estrus Synchronization and Conception Rate of Holstein × Local Crossbred Cows After Using Analogue GnRH and Prostaglandin F2α Hormone

The study was conducted to know the effect of flushed feeding on estrus synchronization and conception rate of Holstein ÍLocal crossbred cow’s after using the GnRH (fertagyl) and PGF2α hormone. As a representative sample 20 Holstein ÍLocal crossbred cows were chosen from Chittagong Cantonment Military Dairy Farm in Bangladesh and the experimental work was carried out for 60 days. Ten cows were flushed with high energy feed (10.5 mega Joule metabolisable energy/kg feed dry matter) and considered as treated group and 10 cows was allowed for normal feeding. Both the control and treated group cows were injected intramuscularly by the GnRH and PGF2α hormone. After injection of these hormones, 100% cows from both groups showed estrus. Fixed time artificial insemination (AI) was done and the cows were diagnosed in pregnancy after 60 days of AI. It was observed that 20% cows were conceived after AI from control group, but treated group cows showed more conception / pregnancy rate (40%). After using the hormones, age of the cow did not influences for estrus synchronization, but for conception rate it was observed that younger cows showed more than older one.