Amongst the environmental factors, hot ambient temperature has significant impact on the productive and reproductive performance of livestock species. Several factors are responsible for causing heat stress and major factors are high ambient temperature and high humidity.
Common symptoms of heat-stressed animal include
Heat stress challenges the production and reproduction performance dairy animals. The milk production declines. Milk composition like milk fat%, SNF% are also affected. Heat stress negatively affects follicular development and estrous cycle.
As cows exhibit lesser heat symptoms during heat stress zones as compared to thermal comfort periods, it is necessary to adopt a good heat detection program to detect cows with marginal heat symptoms. It is always advisable to continue AI breeding instead of using bulls because in natural breeding both bull and cows suffers infertility due to summer stress. Genetic selection of heat tolerant animals and inclusion of heat tolerance as a trait in selection programme will be a boon to the farms.
Fans in combination with water sprinkling facility provide the best cooling option. Excessive sprinkling should never be practised as it can result into wet bedding making animal prone to mastitis and other diseases. The farm should be well ventilated.
Heat stressed animals are more likely to have lower reproductive and productive performance. Feeding high quality forages and balanced rations will decrease some of the effects of heat stress and will boost performance of the animals. Some nutritional management tips to manage heat stress are:
Plantation around the farm will help in alleviating heat load from the animals. But, in today’s commercial dairy industry, it is not always practicable. Therefore, provision of artificial shade area by shade cloth or a naturally well ventilated structure with open sidewalls can keep the animals away from direct solar radiation.
Genetic Selection of animals based on specific molecular genetic markers for heat tolerance will definitely be a boon to alleviate heat stress in cattle and buffaloes by identifying the heat tolerant animals.
Heat stress in dairy animals can challenge the reproductive and production potential of the animals. Implementing proper breeding programs, cooling strategies at farm with better feeding programs can help to minimize some of the negative effects of heat stress.