Cardiorespiratory patterns, rectal temperature, serum electrolytes and packed cell volume in beef cattle deprived of feed and water.

Two trials were conducted with a total of 12 beef heifers and steers to determine the effect of 48-hr deprivation of feed or water or both on rectal temperature, respiratory and heart rates, electrocardiograph (EKG) patterns, packed cell volume (PCV) and the concentrations of serum sodium, potassium, calcium and magnesium. The same measurements plus the serum concentration of total acid-soluble phosphorus were made in a third trial with six steers and a 96-hr deprivation period. A fourth trial was conducted with three rumen fistulated steers to determine the effect of manually emptying the rumen on EKG patterns, Deprivation of feed or water or both for 96 hr reduced (P<.05) rectal temperature by 1.5% and respiratory rate by 47% and increased (P<.05) P and R EKG amplitudes by 33% and 35%, respectively, PCB by 21% and serum phosphorus by 43%. Deprivation reduced heart rate 19% and increased serum sodium and potassium 12 and 23%, respectively, but these changes were not significant. These changes appeared smaller and less consistent for animals deprived for 48 hours. The physiological changes associated with both 48-hr and 96-hr deprivation were most pronounced during the deprivation period and for 24 hr after reintroduction of feed and water with little evidence of treatment effects 48 hr after the reintroduction of feed and water. For animals deprived 96 hr, changes in respiratory rate (P<.01), PCV (P~.05) and serum phosphorus (P<.05) were greater for the animals fed concentrate than for those fed