The types of information recorded on the chart include signs of estrus and results from using other estrous detection aids. Information recorded on a heat expectancy chart also may be useful to a veterinarian diagnosing a cow that is a problem breeder. Heat expectancy charts are often available at low cost through artificial insemination organizations. Mount detectors are glued to the rump of a cow according to the directions supplied by the manufacturer. The mount detector is activated by the weight of another cow mounting the cow on which the mount detector is attached.
Activation changes the detector's color.
Partially triggered detectors may indicate a cow is coming into estrus. The biggest problem with pressure-sensitive mount detectors is false triggering. As a consequence, cows are bred when they are not in estrus which results in low conception rates for the herd. If the cow was bred previously, an abortion may result from breeding the cow when she was not actually in estrus. Use of other signs of estrus or other estrous detection aids to confirm a triggered mount detector is essential to obtain acceptable conception rates.