Effect of temperature-season on bovine adrenal cortical function, blood cell profile, and milk production.
Data collected monthly for one calendar year from Holstein cows lactating under Louisiana ambient climatic conditions comprised a total of 264 cow-months. The year was divided into seasons of cool, intermediate, and hot temperatures. The hot season elicited depressions in circulating corticoids and percent hematocrit. Leukocytosis was a response to increasing ambient temperature primarily accounted for by an increase in circulating neutrophils. Progression from intermediate to hot season gave evidence of eosinophila, and in addition, a relative eosinopenia may have been induced by increased adrenal cortex activity. Milk production was depressed during the hot temperature-season and showed no significant relationship with corticoids of plasma. Rectal temperatures and respiration rates were indicative of heat stress in the hot temperature-season and gave significant negative correlations with circulating corticoid concentration.
D000302:Adrenal Cortex / Q000502:physiology; D000305:Adrenal Cortex Hormones / Q000097:blood*; D000818:Animals; D001772:Blood Cell Count; D001831:Body Temperature; D002417:Cattle / Q000502:physiology*; D004906:Erythrocyte Count; D005260:Female; D006400:Hematocrit; D007774:Lactation; D007958:Leukocyte Count; D007964:Leukocytosis / Q000209:etiology; D008145:Louisiana; D011247:Pregnancy; D012119:Respiration; D012621:Seasons; D013312:Stress, Physiological; D013696:Temperature
D000305:Adrenal Cortex Hormones