~Dr Sagarika Barman and Dr Dibakar Baruah
Buffaloes are well suited to hot and humid climates and muddy terrain, but they exhibit signs of great distress when exposed to direct solar radiation or when working in the sun during hot weather because their bodies absorb a great deal of solar radiation due to its dark skin and sparse coat or hair, and in addition to that they possess a less efficient evaporative cooling system due to their rather poor sweating ability. Amongst different environmental conditions, it is the hot weather that ubiquitously compromises the productive and reproductive performance of livestock species.
The main effects of summer heat in buffaloes can broadly be summarized as:
- Decline in Growth rate
- Lose of weight due to unfavorable period largely due to fall in the status of the feeding.
- There is decrease in the milk production during hot summer of the year.
PHYSIOLOGICAL EFFECT OF HEAT
How to recognize heat stress
- Changes in consciousness: Rapid and weak pulse, rapid but shallow breathing.
- Abnormal vital parameters: Elevated heart rate, respiration rate, rectal temperature.
- Abnormal vital parameters.
- Signs of heat exhaustion: Dizziness / unconsciousness; Skin becomes dull and may be cold too.
- In case of heat stroke – very high body temperature – sometimes as high as 106 – 108°F.
MANAGEMENT OF HEAT STRESS
- SHADE: Simple shade is the basic method of protecting animals from direct solar radiation in day-time during summer. The most effective source of shade is the trees and plants. They provide not only protection from sunlight, but also create a cooling effect through the evaporation of moisture from their leaves.
- AIR MOVEMENT:: Air movement becomes more important during hot-humid climate for providing cooling and comfort to the animal. Air movement increases the rate of heat loss from animal’s body surface, only as long as the air temperature is lower than the animal’s skin temperature.
- EVAPORATIVE COOLING:Various cooling systems have been developed such as holding-pen cooling, exit-lane cooling, and free-stall cooling.An evaporative system which uses water mist with fan is more effective and economises water use in comparison to repeatedly bathing the animals.
- Feeding of green fodders/silage/hay
- Feeding green fodder mixed with dry fodder
- Provision for night feeding to increase the intake
- Grazing early in the morning and late in the afternoon to avoid sun exposure
- Area specific mineral mixture supplementation
- Proper pre-partum feeding of advance pregnant heifers.
- Provision of thermal comfort to heifers, buffaloes and bulls
- Improve heat detection efficiency
- Observe for estrus thrice in a day and at least once during night hours
- Close observation of all non-pregnant buffaloes for cervical mucus discharge and its characteristics
- AI during cooler parts of the day and night
- Insemination between mid and late estrus with good quality semen
- Repeat insemination in case of prolonged estrus
- Provide cooler environment for first 15 days after AI
- Avoid breeding of underweight heifers
- Loose housing is the most economical system of keeping animals.
- Open paddock is provided with shelter along one side under which the animals can take feed and do rest when it is very hot or cold.
- A common watering tank and feeding manager is provided to make management more effective.
- In loose house,animals get optimum exercise and it also facilitate easy heat detection of animals.
- Loose housing system has an advantage over the conventional housing system as cost of construction is significantly lower and further expansion is possible according to requirement.
- . Hormonal alterations associated with heat stress include decline in plasma somatotropin and thyroxine concentrations in an attempt to reduce metabolic heat and consequently, milk production.
- Heat-stressed buffalo exhibits altered blood acid-base chemistry as a result of the shift in thermoregulation from conduction, convection and radiation mediated heat-loss to evaporative cooling. Heat-stressed animal has elevated rectal temperature and respiration rate accompanied with diurnal variations in blood pH and bicarbonate values.
- Water intake: Water is arguably the most important nutrient for buffalo during hot climate.
- Night grazing: Buffaloes kept in a shed maintain rapid heartbeat during the night. However, when the animals are allowed out into a pasture at night, these physiological responses decrease immediately.
- Feeding high energy diet.
- Feeding by pass protein.
In hot-humid climates, although buffalo attempts to acclimatize through physiological changes including cutting down on feed intake and heat production, but this does not come without sacrificing part of its productivity. In order to prevent this economic loss to the farmer, there is need to understand and effectively combat heat stress by minimizing its impact on animal body and its productivity. In the short term, there is no substitute to good management practices to ameliorate heat stress, which include nutritional management and infrastructure facilities for providing comfort to the animal in the event of harsh hot climate.
Authors- Dr Sagarika Barman 1 and Dr Dibakar Baruah 2
- Research Fellow, College of Veterinary Science,
- Khanapara,Veterinary Officer , Demow, Sivasagar