Use of wool growth response to estimate escape of protein supplements from the rumen

Abstract

Wool growth response to formaldehyde-treated (HCHO) casein was used as an index of protein escaping degradation in the rumen. Merino wethers, 3 years old and weighing 41-49 kg, were given a basal diet of oat husks and urea, supplemented with HCHO-treated casein or 1 of 10 protein supplements. All sheep were given DL-methionine 2.4 g. Wool growth indices (%) were casein 10, linseed oilmeal 82, sunflower oilmeal 84, groundnut oilmeal 68, fish meal 113, lupins 83, peas 29, cottonseed meal 83, soyabean meal 73, HCHO-sunflower oilmeal 83 and HCHO-casein 100%. It was concluded that the technique was not sensitive enough to estimate loss of protein from the rumen with accuracy.