Impact of Management and Nutrition on HSP70 Gene Expression in Heat-stressed Dairy Cows

Abstract

Background: This research investigated the effects of management and nutrition strategies on dairy cows under heat stress. Objectives: We aimed to evaluate the effects of zinc mineral supplementation and mist spray, alone and in combination, on yield, milk production and composition, blood parameters and HSP70 gene expression in dairy cows. Methods: Sixteen Holstein lactating cows were used for our experiment in four treatment groups: Basal diet without heat stress alleviation methods (control), zinc supplementation in diet, basal diet and application of mist spray method and supplementation of zinc in basal diet with mist spray. We measured milk production and composition, blood parameters and HSP70 gene expression in all cows. Results: The results showed that the cows in the mist and zinc+mist treatments had significantly better performance and temperature-humidity index than the control group. The milk yield and its compounds were significantly affected by experimental treatments, with the best results seen in the treatment with both spray and zinc. The cows exposed to dry and lactation periods showed a significant increase in the concentration of blood biochemical factors and antioxidant indices in response to heat stress. HSP70 gene expression was significantly decreased in all treatments compared to the control. Conclusion: This experiment suggests that applying nutritional and management strategies can effectively mitigate the effects of heat stress on dairy cows. The study recommends using zinc supplementation and mist spray to alleviate heat stress effectively. Overall, this study highlights the importance of implementing management and nutrition strategies to improve the welfare and productivity of dairy cows under heat stress.