EFFECT OF UREA SUPPLEMENTATION ON SOME METABOLIC PROFILES IN BLOOD SERUM OF SHEEP BEFORE AND AFTER GRAZING

This trial was carried out using twelve growing Ossimi rams previously adapted to urea feeding (initial body weight 29 kg and 7 months age), to evaluate the effects of different urea levels and feeding system (pre and post grazing) on some blood metabolites. Animals were divided into four groups of three animals each: control group was daily fed basal diet without urea and three treated groups were fed basal diet with 1%, 1.5% and 2% urea on dry matter (DM) basis. The duration of the study was 6 months. Animals were kept in a stall for three months (pre grazing period) then they were allowed to graze three hours daily in the morning for the other 3 months. During the pregrazing period, allowed daily feed was divided into two equal portions, while in the grazing period the concentrate portion of the diet was offered to rams in mid afternoon. The results indicated that blood serum total protein, globulin, total cholesterol, urea nitrogen, total bilirubin and glutamic oxaloacetic transaminase (GOT) levels tended to be lower in urea treated groups with different response compared with untreated group. Addition of 1% urea to the diet decreased blood urea nitrogen by 29% (P<0.01). Diet contained 1.5% urea decreased total bilirubin by 30.9% (P<0.05) and GOT by 9% (P<0.05). When sheep were fed 2% urea diet, serum total protein, globulin, total cholesterol and GOT levels insignificantly (P>0.05) decreased when compared with the control. On the other hand, serum glucose and total lipids were significantly higher in urea treated groups when compared with the control. Rams fed 1% urea diet had 23. 3% (P<0.05) more serum total lipids. Serum glucose was higher by 29.7% (P<0.05) when 1.5% urea diet was fed than the other groups. Rams fed diet supplemented with 2% urea had 39.5% (P<0.01) and 9.4% (P<0.10) more serum glucose and total lipids, respectively. However, grazing rams exhibited significnatly higher levels of serum total protein, globulin, total bilirubin and GOT with lower levels of serum albumin, total lipids and glutamic pyrovic transaminase (GPT) than ungrazed group. The study
Assiut Vet. Med. J. Vol. 30 No. 60, January 1994.
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MET ABOLIC PROFILES, SHEEP BEFORE & AFTER GRAZING
declared that feeding with different urea levels improved the nutritional status (daily gain and feed efficiency) of growing rams without adverse effect on the selected serum constituents.