Physiological, oxidative and metabolic responses of lactating water buffaloes to tropical climate of South China

Abstract

Background Heat stress in tropics is generally associated with significant economic losses resulting from reduced performance, morbidity, and mortality of livestock. To avoid serious consequences of heat stress, it is imperative to better understand the physiological responses and biochemical changes under the state of altered body homeostasis during different seasons of the year. Objectives This study aimed to evaluate the seasonal dynamics of physiological, oxidative and metabolic responses of lactating Nili‐Ravi buffaloes to the tropical climate of South China. Methods Physiological responses including rectal temperature (RT), body surface temperature (BST) and respiratory rate (RR) along with serum biochemical and antioxidant parameters of 20 lactating Nili‐Ravi buffaloes were evaluated during different seasons of the year. Results Higher temperature‐humidity Index (THI) during the summer season (>80) resulted in a significant increases in RR and BST as compared to the winter season. Higher oxidative stress was observed in the summer season as revealed by significantly higher MDA while lower serum antioxidant enzyme (TAC, GSH‐Px, SOD and CAT) contents. Moreover, serum cortisol was also significantly higher in summer and autumn. The levels of growth hormone and ACTH were also significantly (P < 0.05) lower in summer and autumn as compared to other seasons. The negative association of THI with physiological and antioxidant parameters was observed while it was positively associated with serum MDA and cortisol levels. Conclusions Our study revealed moderate heat stress in lactating buffaloes in the summer season which calls for attention to avoid economic losses and animal welfare issues.

Effect of the Season on Blood Changes of Oxidative Stress Index in the Italian Mediterranean Buffalo (Bubalis bubalis)

“…RT is a sensitive indicator of the physiological response to heat stress, as it is nearly constant under normal conditions [ 37 ]. However, some authors have reported no significant differences in the RT at different THI levels or seasons on non-lactating buffaloes [ 38 , 39 ]. This is not surprising, since calves and heifers generate less metabolic heat than lactating cows [ 40 ].…”

“…Studies have mostly focused on the effects of diseases like mastitis or acidosis in cattle [ 20 , 26 , 42 , 43 ], but few studies have been reported in buffalo [ 30 , 38 , 39 ]. There are a number of biomarkers that can be used to monitor oxidative stress; however, differences in the endpoints and methodologies used to investigate the oxidant and antioxidant markers make the comparison between studies meaningless, even for studies quite similar [ 38 ]. For instance, Megahed G.A., et al [ 34 ].…”