THERMOREGULATORY BEHAVIOR OF BUFFALOES
Divya Patel1, Nutan Chouhan2, Garima Kansal1
- PhD Scholar, Division of Livestock Production Management, NDRI, Karnal, Haryana
- PhD Scholar, Division of Animal Nutrition, NDRI, Karnal, Haryana
Email: ddnv4321@gmail.com
Introduction
The domestic buffalo is a multipurpose species (meat, milk, work) that presents two types (river and swamp). Water buffalo are well adapted to swamps and flooding area. In homoeothermic animals, thermoregulation involves both physiological and behavioral responses. Some mammal species have a high capacity to dissipate heat (e.g. humans, horses), while in others, the ability to sweat is limited (e.g. dogs, cats, pigs, and buffaloes have few sweat glands) or non-existent and need to rely on different mechanisms to efficiently thermo regulate. Because of its scarce hair and dark skin, the river buffalo’s body absorbs large amount of solar radiation that make it susceptible to thermal stress. At the same time, this species’ evaporative cooling system may be inefficient if the environmental conditions and farming facilities are inappropriate. For these reasons, it is important to understand the buffalo’s behavioral habits and physiology and their relation to thermoregulation.
Heat stress
Heat stress occurs when the body temperature is elevated, due to excessive metabolic heat production or high ambient temperatures, or reduced heat loss. Extreme ambient conditions can negatively affect animal production. Temperature, humidity, ventilation and light are related to the regulation of metabolic processes in animals, affecting the ability of the individual to adapt to its environment. In this way, many productive and reproductive parameters can be compromised, like nutrient intake, weight gain, milk production and fertility. Temperature Humidity Index combines effects of two variables temperature and humidity on animal production, serves as an indicator of effects of potential heat stress periods on livestock. Physiological responses to thermal stress in animals include the activation of endocrine, autonomic and central nervous systems, as well as cardiovascular mechanisms for redistribution of blood flow. All of them act in a synergistic way depending on the magnitude of the stress factor and they respond to it by generating physiological mechanisms to suppress or decrease the threat of the adverse effects of the stressor.
BEHAVIORAL CHANGES DUE TO HEAT STRESS
Livestock’s behavior is directly in relation to that of its status of well-being. The effect of heat stress and other environmental changes often leads to a reduction in the animal’s performance and productivity. Changes in the behavioral pattern can indication a dreadful environment. The major behavioral responses to livestock adaptation are feeding, defecating and urinating frequency, water intake, lying time, standing time, shade seeking behavior and increased frequency of drinking. There are also several factors influencing these behavioral responses which have been depicted
Feeding: When the cattle are exposed to hot environmental conditions, reduced feed intake was observed. Feeding act as a source for heat production in ruminants, reduction in feed intake can help to decrease heat production during warm climate and due to this negative energy balance body weight and the body condition score will go down. It was seen that cows showed an increased probability of starting to feed with the advancement of time since the last feeding. Under heat stress conditions dairy cows show a reduced rumination but if the feed contains high starch content, longer rumination was observed in order to reduce the ruminal PH.
Defecation and urination: Urination and defecation are a common natural physiological process of the livestock. The frequency of urination and defecation vary with the factors affecting the livestock like water intake, feed intake, type of feed, environmental temperature, disease condition, immunity of the animal and stresses etc. Among the stresses, heat stress frequency of urination and defecation decreases.
Lying and standing behavior: The changes in behavior associated with high heat stress increases the standing time. The animals maximize the evaporative heat loss from the body surface and assist in convection by standing more time to get away by the conductive and radioactive heat from the hot ground surface. Further, the time spent on standing has increased by 10% (13.8-15.3 h dayG1) when the heat load increased by 15% (THI = 60-70) to enhance the heat loss by increasing the surface area of skin exposed to air or wind flow. The higher standing time during heat stress is an adaptive behavioral mechanism in animals to avoid the additional heat load from the ground and to favor easy heat dissipation form the body. Further, standing diminishes heat gain by direct contact with the ground and tends to decrease heat stress. The conductive heat loss is minimal in the standing animals due to the presence of a layer of air against the skin where most of the body heat load is transferred to the air. In addition, the standing animals transmit its heat load to the ground only by the feet with a small area of contact. Moreover, the distance between the blood vessels and surface area is much greater in the feet of the animals than its skin.
Shade seeking behavior: The shaded structures are commonly used on dairy farms to alleviate heat stresses condition in animals. Cows gave more preference towards standing in the shade rather than lying during hot weather conditions. Cows preferred shade created by iron roof even when given access to every shade type (like shade cloth, choko vines and single trees) because it blocked 70% of solar radiation provided that less solar radiation was allowed to fall on it. Another study shows the preference of cows towards shade created by trees due to the efficiency in blocking the solar radiation and evaporation from leaves which causes the air to cool rather than artificial shade. Buffaloes seek for shade in the absence of wallows and shade seeking is a common behavior among livestock to adapt to hot humid conditions.
Water intake and water drinking frequency: Water is an important nutrient during heat stress and the properties of water are an important factor for the transfer of heat from the body to environment. Cows generally prefer moderate temperature water to drink, which is neither too cold nor too hot. The consumption of water will be 40% higher during summer than that in winter. The temperature of water is also a crucial factor, generally cold water can be given during hot conditions and water temperature below the body temperature would be better than warm water. The salinity of water also may increase during hot conditions due to evaporation. The increased consumption of water is used to dissipate heat and for cooling the reticulo-rumen. Water intake by cattle can be affected by many factors including water quality and ambient temperature.
Wallowing: Wallowing behavior is a learnt behavior, especially in buffaloes. The wallowing behavior of animals can enhance their level of production of buffalo heifers as well as improve their welfare. Wallowing would enhance the grazing time of buffaloes because it reduces the heat stress. Buffaloes are adapted to the tropical and sub-tropical climatic conditions because of their thermoregulatory mechanisms such as wallowing that would protect them from solar radiation and provide cooling effect. It was reported that the greater amount of wallowing occurs during the sunrise and sunset time and especially during high solar radiation. Generally wallowing is done for two purposes, one for cooling purposes and the other for protection from insect. Wallowing is done both during day and night time. During the day time it is done in the hottest period and at night time it is done to protect it from insects.
FACTOR AFFECTING BEHAVIORAL RESPONSE
- Feeding – Milk production, body weight,, disease, competitive feeding,, feeding space/time/frequency, calving, design of feed barrier and heat stress.
- Shade seeking – Heat load/stress, roofing/shade, types/colour, colour of the animals.
- Defecation and urination – Shade seeking Lactating cows, walking, milk, production, temperature of barn,, ambient temperature, type of breed,, relative humidity, compulsory, standing and walking, quality and, quantity of feed, excitement of animal,, high body movement, resting time
- Lying – Design of resting area, environmental conditions, gestation, time, lameness, feeding, milking
- Milking – Vocalization/companionship,, grazing, lactation period, milking, frequency, machine milking,, attachment with calves, lameness,, odour of the calves,multiparous/primiparous
- Standing – Design of resting area, environmental conditions, gestation time, lameness, feeding, milking
- Heat stress – Heat stress, cold stress, ambient temperature, temperature of drinking water, lactation, eating pattern, cow dominance, calving, access to watering area, relative Water intake
- Wallowing – Heat stress/high temperature, high relative humidity, prone to attack of insects
COLD STRESS
All mammals are warm blooded and need to maintain a constant core body temperature. Animals experience cold stress when the temperature falls, below the lower limit of thermo neutral zone, called the “lower critical temperature”. Increase in metabolic activity of body to generate more heat, is the first reaction of body to combat the effects of cold stress. When environmental temperature decreases below the thermal comfort level, heat loss must equal endogenous heat production (thermo genesis) in order to achieve homeostasis, i.e. maintenance of body temperature in a stable thermo neutral range. Cold stress activates several physiological responses.
BEHAVIORAL CHANGES DUE TO COLD STRESS
Water buffalo activities can be divided into two: winter and summer activities. Water buffalo are very sensitive to changes in temperature. It has been observed that animals increase their food consumption when it is cold; this allows them to maintain a higher metabolic rate and, consequently, to increase heat production, which gives them greater tolerance to cold. Main behavioral responses of cows to cold and wet conditions were reductions in resting and feeding time. If the surface is wet, resting behavior is inhibited. When there is cold stress, the energy ingested through food can be diverted towards the maintenance of functions for the generation of body heat. In the cold stress condition local people provide fodder directly to the animals in their yards in winter. Thus, the amount of buffalo milk increases in the winter and trading milk and fodder becomes the dominant economic activity during winter and spring. If food provision is not possible, capacity to produce heat is decreased and can generate various respiratory diseases, diarrhea in young animals, pneumonia and finally death. The minimum critical temperature is defined as the ambient temperature below which the animal has to increase its heat production to prevent its body temperature from falling. The reduction of the exposed body surface when the animal is rolled up also reduces heat loss by convection. Also, social thermoregulation is a behavior that consists of maintaining close body contact with other individuals, so that the surface exposed to the environment decreases. In a way, by keeping very close together, animals acquire the thermal advantages of a very large animal, thus increasing its resistance to cold. Recommends that for buffalo kept in cold climates it is necessary to have a shelter that protects animals from rain, snow and strong winds, this can be a simple construction with a roof and three walls, this system It allows buffaloes to graze when the weather permits, it also points out that there should be a feeding area inside the shelter in case there are several days with low temperatures and in this case, a separate warm milking area is recommended. He also mentions that it is important to have access to a clean and dry straw bed.
Conclusion – Behavioural response is the first step taken by animal to combat the stress, studying the animal behaviour is a useful tool not only to overcome the stress but also to understand how to best use and design strategies to manipulate the micro-environment. The behavioural attitudes of livestock towards climate change are complex and it is not well understood by the farmers. Adaptation is not only the tolerance level of the livestock of environmental stresses but also their ability to grow and reproduce in comfortable environment
https://www.frontiersin.org/articles/10.3389/fvets.2020.522551/full
