The actual percentage of cows in heat during a 24-hour period can be influenced by the season of the year, with more cows showing heat at night during hot weather and more showing heat during the day during cold weather. Housing conditions also can have an effect on the distribution of heat during a 24-hour period. The important point to remember is that heat can occur at any time. Detect Heat Keen observation is of primary importance in detecting heat. Several aids also are available to help confirm and identify cows not exhibiting obvious signs of heat.
All aids require careful management and proper interpretation to be successful.
Other factors that may assist conception are discussed in items five and six. Anticipate heat with records. By recording accurate herd heat detection and insemination information on barn charts, individual cow record cards, and heat expectancy charts, it is possible and practical to project when cows are most apt to come into heat. Cattle identification by tag number and sound record keeping make it possible to know which cow is bred to which bull, and whether or not she has been bred before. Chin ball markers are quite effective.