Impacts of heat stress on blood metabolic in different periods of lactation and pregnancy in Holstein cows

Abstract

Heat stress (HS) greatly affects sustainable livestock production, thereby affecting the productive performance and welfare of animals. The effect of summer heat on lactating Holstein cows at different lactation, pregnancy phases, and blood metabolism were investigated in this study. Eighteen Holstein cows were selected randomly and housed in the cow farm. Climatic reads and blood parameters were measured. The temperature-humidity index has been designed as a measure of animal comfort and is a simple combination of temperature and humidity. The study showed that heat stress has a significant effect (P ≤ 0.01) on hematological and biochemical parameters. Mean platelet volume (MPV) and red blood cell distribution width (RDW) were reduced significantly (P ≤ 0.01) during lactation. There was a significant increase in creatinine level at 45 days in milk. A significant inverse correlation between HS with milk production and feed intake. So far, it was concluded that certain hematological and biochemical parameters were substantially altered by HS. A negative effect of HS on milk production and feed intake was observed.