Animal Science Department


Date of this Version

January 1973


Published in JOURNAL OF ANIMAL SCIENCE, vol. 36, no. 1, 1973. Copyright American Society of Animal Science. Used by permission.


Thirty-six Angus-Hereford steers were fed four diets of different potassium concentration for 2-week periods such that each steer received each diet for a 2-week period. The relationship between 40K count loss and weight loss during a 24-hr. shrink period was evaluated by regression analysis. At the end of each of the four feeding periods the steers ,were weighed and 40K counted unshrunk and again after 24-hr. shrink.

The mean weight loss during shrink was similar for all treatments (overall mean of 22.8 kg), however the mean 40K count loss was larger for the high potassium diets than for low potassium diets although the rank of these means did not correspond to the potassium content of the diets. The overall loss in 40K count during shrink was 708.3 (S.D.= 449.2) counts per minute. The regression coefficients of count loss on weight loss during shrink were not significantly different among treatments. The pooled regression coefficient was 22.5 ± 5.4 cpm per kilogram.

When 40K count was regressed on weight, all regression coefficients were significantly (P <.01 ) greater than zero, however regression coefficients for the various treatments were not significantly different from each other, although there was a tendency for coefficients to be higher for high potassium diets and on unshrunk measurements. Pooled unshrunk and shrunk regression coefficients of 40K count on weight were 14.75±1.92 and 12.41±1.76 cpm per kilogram, respectively.