Control of Oestrus and Ovulation in Cows

Although the methods and techniques that will be used to synchronize follicle growth and ovulation in the future may yet to be discovered, many tools that are needed may already exist. Once synchronous growth of a competent dominant follicle occurs, ovulation can be induced at a predictable time by applying drugs or hormones that induce LH release, or by administration of exogenous LH. Development of a practical method for fixed-time AI offers significant advantages to dairy producers if conception rates are close to those seen in breeding after detected estrus. Development of routine methods based on the use of GnRH and PGF for resynchronization should help dairy producers improve reproductive performance. The control of estrus and ovulation program can benefit dairy operation because it allows for timed AI of lactating dairy cows without detection of estrus. However, the cost hormone administration should be considered when selecting this form of reproductive technology for routine use. Any synchrony programs should be used under considerations that reflect the complexities of interactions among management skills, milk production, environment, and nutrition. Alternatively, improved estrus detection will increase effectiveness of other reproductive protocols. [PUBLICATION ABSTRACT]