Estrus (Heat) Detection in Cattle
Estrus in cattle is commonly referred to as heat. It occurs every 18 to 24 days in sexually mature, open (nonpregnant) female cattle when they are receptive to mounting activity by bulls or other cows or heifers.
Heat detection is critical to heat synchronization and breeding programs, particularly artificial insemination and embryo transfer programs. Effective heat detection is often the most limiting factor in an artificial insemination program. Heat detection can also be used to monitor onset of puberty in heifers, regularity of estrous cycles in breeding age females, and breeding effectiveness of natural service sires via returns to heat in the cow herd.
Heat detection efficiency (rate) is the percentage of eligible cows seen or detected in heat. Eligible cows are cows eligible for insemination. Heifers have reached puberty if they have resumed normal estrus function (cycling) after calving (typically 40 days or more postcalving), are free of reproductive disorders or reproductive tract infections, and are open. A heat detection rate of 80 to 85 percent should be attainable.
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