TIMED ARTIFICIAL-INSEMINATION IN DAIRY-CATTLE - PART I

A timed artificial insemination (TAI) protocol using gonadotropin-rele asing hormone coupled with prostaglandin F-2 alpha has been developed that improves reproductive performance in lactating dairy. cows. This protocol synchronizes ovulation, followed by TAI ata fixed time, and i s thus known as OvSynch/TAI. Because ail cows are inseminated, the pro tocol eliminates errors in estrus detection (i.e., failure to detect c ows that are in estrus); consequently. pregnancy rate improves. Improv ing the pregnancy rate results in a decrease in the calving-to-concept ion interval, which positively influences herd net income. Using OvSyn ch/TAI can allow for first insemination to occur 75 days postpartum, w hich is when most dairy cows are returning to a positive energy balanc e. Implementing the OvSynch/TAI program to all cows on a given day pos tpartum also eliminates the problem of first insemination occurring to o early or too late in lactation. In addition, the OvSynch/TAI protoco l improves reproduction during periods of heat stress by eliminating e rrors in estrus detection caused by heat stress. The OvSynch/TAI proto col could eliminate the need for estrus detection from a dairy herd, p articularly if early pregnancy diagnosis is performed with transrectal ultrasonography. Part I of this two-part presentation discusses the p rotocol and uses of OvSynch/TAI; Part II will review the economic anal ysis that compares the cost:benefit ratio between TAI using the OvSync h protocol and insemination at detected estrus.