The Challenge of Global Warming in Water Buffalo Farming: Physiological and Behavioral Aspects and Strategies to Face Heat Stress

Abstract

Water buffaloes have morphological and behavioral characteristics for efficient thermoregulation. However, their health, welfare, and productive performance can be affected by GW. The objective of this review was to analyze the adverse effects of GW on the productive behavior and health of water buffaloes. The physiological, morphological, and behavioral characteristics of the species were discussed to understand the impact of climate change and extreme meteorological events on buffaloes' thermoregulation. In addition, management strategies in buffalo farms, as well as the use of infrared thermography as a method to recognize heat stress in water buffaloes, were addressed. We concluded that heat stress causes a change in energy mobilization to restore animal homeostasis. Preventing hyperthermia limits the physiological, endocrine, and behavioral changes so that they return to thermoneutrality. The use of fans, sprinklers, foggers, and natural sources of water are appropriate additions to current buffalo facilities, and infrared thermography could be used to monitor the thermal states of water buffaloes.

Keywords: behavior and thermoregulation; global warming; heat stress; infrared thermography; water buffalo.

Figure 1

Main effects of heat stress on water buffaloes and bovines of the genus Bos. (A) Animals from the Bos genus. (B) Animals from the Bubalus genus. HR: heart rate; LH: luteinizing hormone; RR: respiratory rate; RT: rectal temperature; TSH: thyroid-stimulating hormone.

Figure 2

Thermoregulatory pathway of water buffaloes when facing heat stress. Peripheral thermoreceptors process and transmit information about the external thermal environment of mammals. Through a complex connection between the spinal cord (DRG and DH), the LPBd, and supraspinal structures (primarily the POA, MPO, and MnPO), the organism triggers different responses to increase heat dissipation. For example, the vasodilation of dermal arterioles and capillaries increases heat loss in water buffaloes exposed to heat stress. Similarly, other compensatory mechanisms such as increases in respiratory rate and heart rate serve to restore thermoneutrality. DH: dorsal horn; DMH: dorsomedial hypothalamus; DRG: dorsal root ganglion; GABA: gamma amino butyric acid; GLU: glutamate; HPA: hypothalamic–pituitary–adrenal; IML: intermediolateral; LPBd: dorsal part of the lateral parabrachial nucleus; MnPO: median preoptic nucleus; MPO: medial preoptic area; NE: norepinephrine; POA: preoptic area; rMR: rostral medullary raphe region; SAM: sympathetic-adrenomedullary; ↑: increase; ↓: decrease.

Figure 3

Structure and species-specific characteristics of water buffaloes’ skin.

Figure 4

Thermoregulatory behaviors of water buffaloes when exceeding their thermoneutral zone. When the thermoneutral zone of the animals is exceeded and they begin a process of thermal discomfort, they present a series of behaviors to increase heat dissipation. For water buffaloes, the most common thermoregulatory behaviors are immersing themselves in flood zones, wallowing in mud, searching for shaded areas, and modifying their feed intake schedules or reducing their feed intake.

Figure 5

Productive performance of Nili Ravi buffaloes under different ambient management interventions. (a) kg of milk produced per day under different conditions: shade (control); shade and fan; and shade plus fan plus sprinklers. An increase of 0.7 kg/day was observed when implementing shade plus fans, while an increase of 3.14 kg/day was reported when using the three elements. (b) Percentage of fat in buffalo milk. It was observed that the use of three resources increased milk fat by 0.74%. (c) Percentage of protein in buffalo milk. The control group presents 3.39% protein, 0.2%, and 0.4% less than those shown by other groups. (d) Percentage of lactose in buffalo milk. In the same way, the control group shows the lowest percentages of lactose (4.11%), followed by the group with shade and fan, with an increase of 0.21%, and the highest values on shade plus fan plus sprinklers.

Figure 6

Variation of rectal temperature and respirations per minute in buffalo calves at 9 A.M. and 2 P.M. under different types of roof materials. (A) Rectal temperature of calves. It is shown that all the roofs, except for the asbestos roof, have the highest temperature at 2 P.M, with a difference of up to 0.25 °C compared to that presented at 9 A.M. Likewise, it is observed that the buffaloes under the pre-painted CGI sheet roof and galvanized iron sheet roof have the highest temperatures in both hours, while the lowest temperature is recorded in buffaloes under thatch with polythene shading roof, with a difference of 0.5.°C in comparison with the pre-painted CGI sheet roof. (B) Breaths per minute. Observe the difference in respirations shown at different times of the day. Thatch with polythene shading roof recorded 8.4 breaths per minute, which is less than those expressed with the galvanized iron sheet roof at 2 P.M.