Estimating Creatinine Excretion in Sheep

Abstract

Urine was collected by catheter from 12 ewes at 6-hr, intervals for 5 consecutive days to evaluate sources of variation in creatinine excretion rate for the purpose of determining satisfactory collection procedures. There was no significant difference among days when the first day was considered as a standardization period. Excretion rates averaged 0.79 mg./hr./kg. of live weight and 38.0 mg./hr. and were significantly (P<.005) different among ewes. More creatinine was excreted from midnight to 6 a.m. than from 6 a.m. to noon (P<.005). Excretion rates for 6-hr, intervals starting at noon or at 6 p.m. were approximately the same as the 4-day average. Creatinine excretion rate varied significantly (P<.001) among 6-hr, intervals but not among 12- and 24-hr, intervals. The coefficients of variation were 10.2, 6.8, 7.3 and 5.5%, respectively, for 6-hr, intervals, 12-hr, intervals beginning at noon, 12-hr, intervals beginning at 6 a.m. and 24-hr, intervals. The part-whole correlations between accumulative average excretion at 24-hr, and 48-hr, of the 4-day experimental period and the 4-day average by ewes were 0.90 and 0.95, respectively. For 24-hr, intervals, 90% of the collections from individual ewes differed from the 4-day average by less than 10%, as compared with 80% for 12-hr, intervals and 66% for 6-hr, intervals. Copyright © 1967. American Society of Animal Science . Copyright 1967 by American Society of Animal Science