Pathological features in sheep fed rations containing phenolsand condensed tannins

A study was carried out to investigate the effects of feeding low quality non-conventional feeds (NCFs) containing phenols and condensed tannins on the pathological features of sheep. Thirty-two sheep were fed one of 4 ration combinations of 2 roughages, urea treated palm frond and Rhodesgrass hay and 2 concentrates, commercial concentrate and by-products concentrate for 120 days. Non-conventional feeds (palm frond and by-product concentrate) contained higher levels of phenols and condensed tannins than conventional ones (Rhodesgrass hay and commercial concentrate). Villus height and height: Crypt depth ratio were significantly lower in animals on the NCFs. There were signs of chronic inflammation in the intestine; the kidneys showed signs of nephritis and the liver showed congestion and hemorrhagic changes. This experiment indicated that feeding non-conventional feeds containing phenols and condensed tannins for extended periods may produce subtle negative effects on animal health and production.