#1 Heat detection Visual Heat Detection A large number of studies show that cows’ heat behaviour has weakened over time. On one hand, you can try to improve/ strengthen cows’ ability to show heat. On the other hand, you can try to improve the sensitivity of the way you do heat detection. Finding the problem The frequency of finding heat when detecting visually depends on the number of observations per day, the time of observation and the duration of each individual observation. Low heat detection rate may be due to detecting heat at the wrong time, or in shorter periods of time. If you have more staff members detecting heat at different times, it is important to agree on which heat signals to look for and which signals should lead to insemination and that the information is handed on and collected. Causes The best times to detect heat in a herd depends on the work routines in the individual herd, but not at the same time as the cows are busy doing other things. Heat signs can be categorized as: • No certain signs of heat • Reliable signs showing that the animal is in early heat. Service within 10-20 hours • Very reliable signs of heat. Service immediately Focus areas • Include as many heat signs as possible when detecting heat • Perform heat detection minimum three times a day for at least 20 minutes a time (one should be in the night between 6 pm – 6 am. • Combine visual heat detection with activity measurements • Train your staff members doing heat detection thoroughly and enable them to pass on information to each other. Heat detection technologies With increasing herd sizes and more cows per staff member, a need for tools to manage the work with reproduction may arise. The most used activity monitoring systems have neck tags with movement sensors. Such systems measure the activity level continuously and this will be compared with the average activity level for the individual animal. If the animal differs positively or negatively compared to the average level, the animal may be in heat or be sick. Finding the problem If the service rate is low when using technology for heat detection, it is recommended to check the technique, applications and limit values of the system. Evaluate the system alarms in combination with cows’ heat behaviour and AI technician experience when servicing. On the contrary, if the pregnancy rate is low, focus should be put on the time of service compared with the heats detected. Low pregnancy rate may also be due to faulty settings of the system resulting in alarms for animals that are not in heat. Focus areas • Check the system compared to the user guideline from the system provider and the data available • Evaluate routines for moving transponders between animals • Evaluate number of transponders compared with number of animals 3
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