Suspected “B”-Vitamin Deficiency of Sheep Fed a Protein-Free Urea Containing Purified Diet

Abstract

Symptoms ofcerebrocortical necrosis (CCN) were observed in sheep fed a synthetic protein-free urea diet for 7 months. When six of the B vitamins were supplied individually into the rumen of sheep in the feed refusal state only thiamine and, to some extent, nicotinamide were able to restore feed uptake for a few days. Thereafter feed refusal was observed again. A vitamin B complex solution re-established normal feed intake for 2 to 3 weeks. Ruminal thiamine concentrations in diseased sheep were extremely low. During the vitamin dificient state, butyric acid production in vitro increased significantly, mainly at the expense of propionic acid formation. Thiamine added to incubations in vitro was almost entirely transferred to the solid phase of the samples, and about 25% of the thiamine added could not be recovered after 1 hour. Rumen motility and mixing of rumen contents markedly decreased when deficiency symptoms developed. Total fermentation rate, microbial growth, dry matter digestibility and nitrogen balance were not changed during the deficient state. Urine volume drastically increased in diseased sheep.