Short Term Changes in Plasma Hormones, Metabolites, Milk Yield and Physiological Responses in Epinephrine Administrated Cows

This investigation summarizes the effect of epinephrine administration on milk production and plasma hormones. The epinephrine and nor-epinephrine hormone are released during stress and may have adverse effect on milk yield of lactating animals. Lactating cows were administered epinephrine intravenously (@0.5 ug/kg body wt./ day) for a period of five days. Blood samples were collected before and after the administration of epinephrine. Plasma metabolites and hormones were analyzed. Epinephrine treatment significantly increased plasma epinephrine and nor-epinephrine (P<0.01) levels concomitant to decline in milk yield (P<0.01) in all the cows on day 1 of injections and the effect on milk yield continued during the treatment period. Plasma insulin and glucose level increased (P<0.05) after the treatment, however plasma cortisol, thyroid hormone and NEFA level was not influenced by treatment. Further, there was no effect of treatment on milk composition (fat, protein, lactose, solid not fat and somatic cell count), respiration rate, pulse rate, rectal temperature and skin temperature. It was concluded that elevated plasma epinephrine and norepinephrine level inhibit milk secretion (P<0.05) in cows, however milk composition, physiological responses and plasma cortisol levels remain unaffected.