Journal of Animal Science, Vol 74, Issue 10 2331-2335, Copyright © 1996 by American Society of Animal Science

JOURNAL ARTICLE

Protein and energy value of dehydrated poultry excreta in diets for feedlot cattle

R. A. Zinn, R. Barajas, M. Montano and Y. Shen
Imperial Valley Agricultural Center, University of California, El Centro 92243, USA.

Four Holstein steers (222 kg) with cannulas in the rumen and proximal duodenum were used in a crossover design experiment to evaluate the energy and protein value of dehydrated poultry excreta (DPE). Dietary treatments contained (DM basis) 4% alfalfa hay, 8% sudangrass hay, 49% flaked barley, 8% cane molasses, 3% yellow grease, .8% urea, 1.4% limestone, .3% mineral salt, and .4% chromic oxide, plus 25% of either tapioca pellets or DPE. The DPE contained 42% ash and 27% CP (6% true protein). Substituting DPE for tapioca decreased the DE value of the diet (P < .01). The estimated DE value of the DPE was 1.36 Mcal/kg (.34 Mcal NEm/ kg). There were no treatment effects (P > .10) on microbial N flow to the small intestine or ruminal microbial efficiency (grams of microbial N/kilogram of OM fermented). The addition of DPE increased (P < .05) the flow of non-ammonia and feed N to the small intestine. The estimated ruminal escape N value of DPE was 22%, although very little of this was true protein. Dehydrated poultry excreta did not increase (P > .10) flow of alpha-amino N to the small intestine. Ruminal degradability of uric acid was 96%. Total tract true digestibility of N in DPE was 84%. It is concluded that the NE value of DPE is markedly overestimated in current tables of feeding standards. Less than 10% of the N in DPE escapes the rumen as true protein N.