Studies have shown that as many as 20 percent of the cattle presented for insemination are really not in heat. Poor cow identification can be one cause of this problem. Legible neck chain numbers, large ear tags, and freeze brands can aid in accurate cow identification and reduce mistakes. Consider using heat detection aids to help increase the number of heats detected. Detection devices and detector animals should be used only in conjunction with routine visual observation.
Proper nutrition is critical to optimum reproductive performance.
Energy deficiency, excessive or inadequate protein levels, mineral and vitamin imbalance, and conditions causing anemia or infection are possible causes of poor expression of heat and inferior conception rates. However, dairymen and AI technicians can control and influence conception rates by using proper procedures of semen storage, semen handling, and insemination technique. Such procedures provide the most viable population of sperm at the proper site in the reproductive tract. Dairymen who breed their own cows, or who receive technician service, should handle each cow individually so that each is bred toward the end of standing heat. Poor heat detection and breeding of cows based on secondary signs of heat will cause poor conception rates and excessive days open.