Management of Dairy animals during heat stress

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.

Signs of heat Stress

Common symptoms of heat-stressed animal include

• Animal moves to shade
• Water intake enhanced while feed intake reduced
• Prefers standing than lying down
• Increased respiration rate, body temperature
• Increased production of saliva
• Open-mouth panting

Reproductive and Production Challenges

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.

Strategies to reduce the negative effects of heat stress

Breeding Management

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.

Cooling systems in the farm

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.

Feeding Management

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:

• Provide high quality feeds like total mixed rations
• Increase the frequency of feedings
• Feed during cooler times of the day
• Keep feed fresh as much as possible
• Provide high-quality forage
• Provide adequate fibre
• Use of by–pass proteins  can enhance the milk yield and protein content.
• Intake of sufficient cool water is probably the most important strategy for animals to undertake during heat stress.

Providing natural or artificial shade area

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.

Selection of heat tolerant animals

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.

Conclusion

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.

References

1. Managing Reproduction during Times of Heat Stress, ABS Global Technical Services Newsletter
2. Rensis, Fabio D. and Rex.J. Scaramuzzi. 2003. Heat stress and seasonal effects on reproduction in the dairy cow—a review. Theriogenology 60:1139-1151.
3. Buffalo under Heat Stress, AK Balhara, Jerome A and Inderjeet Singh. Central Institute for Research on Buffaloes, Indian Council of Agricultural Research.

Source

1. Adhikari Sahu, College of Vetrinary Science Korutla, Telengana
2. Rajalaxmi Behera, ERS of ICAR-NDRI, Kalyani, West Bengal