Journal of Animal Science, Vol 68, Issue 11 3886-3896, Copyright © 1990 by American Society of Animal Science

JOURNAL ARTICLE

Nutrient intake and digestion as influenced by wash water solids as a protein source for lambs fed orchardgrass hay

T. May, J. E. Williams, J. S. Caton and E. E. Beaver
Dept. of Anim. Sci., University of Missouri, Columbia 65211.

Two experiments were conducted with sheep fed orchardgrass hay plus one of four supplements to evaluate use of a cheese processing wash water solid (WWS) material as a protein supplement. In both trials, lambs were fed either a cornstarch control (0% WWS-N) or a protein supplement containing 25, 50 or 75% N from WWS (25, 50 or 75% WWS-N, respectively). The majority of the remaining protein was supplied by soybean meal (SBM). Trial 1 was a replicated 4 x 4 extra-period Latin square. Protein supplementation increased total tract NDF and N digestibilities (P less than .10) 13% and 29%, respectively, compared with the cornstarch control. Total tract N digestibility was depressed (P less than .10) when 75% WWS-N (71.5%) vs 25 or 50% WWS-N (75.9 and 75.9%, respectively) was fed. Total VFA were depressed (P less than .10) 6 and 9 h postfeeding in sheep fed 75% WWS-N compared with the control (78.3 and 74.6 mM vs 98.8 and 94.6 mM for 6 and 9 h, respectively). Two hours postfeeding, lambs fed control had lower (P less than .10) ruminal pH compared with lambs fed 25, 50 and 75% WWS-N (6.2 vs 6.4, 6.5 and 6.5, respectively). Ruminal ammonia concentrations were 5 to 10 mg/dl lower (P less than .10) at all times in control lambs. In Trial 2, a metabolism study, feeding 75% WWS-N resulted in lower N digestibility (P less than .10) than did feeding 25% and 50% WWS-N (47.2 vs 56.4 and 55.2%, respectively). Data suggest that up to 50% of the SBM-N in a protein supplement for wethers may be replaced by WWS-N without adversely altering nutrient digestibility, ruminal fermentation or N metabolism.