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Dairy Pipeline: February 2009
John Currin
Extension Dairy Veterinarian
(540) 231-5838; jcurrin@vt.edu
Heat Detection presents a real challenge on modern dairy farms. The simple answer to heat detection has always been to spend more time watching cows for signs of heat. The problem is that there are many tasks competing for time around the dairy. Add the fact that the modern dairy cow only shows heat for about 8 hours and heat detection can be a real challenge. None of this changes the fact that in order to avoid losing cows from semen deficiency, cows must be found in heat. There are three ways to improve heat detection.
The first way is to put more emphasis on heat detection. There are many ways to accomplish this goal. One person on the farm must be put in charge of heat detection. The old saying “if it’s everyone’s job it’s no one’s job” is apt when it comes to heat detection. While everyone can help with heat detection, having one person who is ultimately responsible will improve the program’s success rate.
The second option to improve heat detection is to use one of the timed artificial insemination (TAI) protocols like Ovsynch. Since all synchronized cows are inseminated, heat detection for that cycle will be 100%. One of the big misconceptions in TAI protocols is that they eliminate heat detection. While they do eliminate heat detection for the cycle the cows were synchronized, as many as 70% of these cows will likely not conceive and thus will be coming in heat 18-23 days later.
The final method of improving heat detection is to simply put a bull in with the cows. Bulls are often considered to have 100% heat detection. When young, fit, and healthy this fact is close to true. The problem with bulls on dairy farms is that they must be managed to ensure that they maintain healthy feet and legs and are free of other health problems. The most common mistakes with bull breeding herds are having too few bulls for the number of cows and not monitoring bulls for health problems.