ASSOCIATIVE EFFECT OF MOLASSES-UREA BLOCK AND FORAGE QUALITY ON NUTRIENT DIGESTION AND NITROGEN RETENTION IN SHEEP

A study was conducted in a 4x4 Latin square design involving four adult crossbred (Kaghani x Rambouillet) weather kept in individual metabolic crates and four experimental diets viz: maize stovers (Diet A), maize stovers with 150 g/d molasses-urea block (Diet B), lucerne hay (Diet C)and lucerne hay with 150 g/d molasses-urea block (Diet D). The forage intake was restricted to 2% of body weight. Each experimental period consisted 10 days of adaptation followed by five days of data collection. Total dry matter intake on molasses-urea block (MUB) supplemented diets was higher (p<0.05) than unsupplemented diets. The daily quantity of total dry matter and water consumed by weathers was higher (p < 0.001) on MUB supplemented diets. Water consumption was positively co-related to nitrogen intake (r2 0.66: p< 0.00 I) and varied due to diets (p < 0.00 I). in vivo dry matter digestibility (DMD) and organic matter digestibility (OMD) of lucerne hay-based diets were greater (P< 005) than those containing maize stovers. Supplementation of MUB did not affect the DMD or OMD of the diets. The interaction of MUB and forage (P = 0.06) revealed that MUB was effective in increasing (P< 0.05) the nitrogen digestibility of maize stovers from 30,59% on diet A to 51.33% on diet B but did not affect the nitrogen digestibility in animals fed lucerne hay. The wethers receiving lucerne hay-based diets retained more nitrogen (p< 0.001) than those given maize stovers (8.50 's 3,12 g/d). Molasses-urea block supplementation on both forages increased (p < 0.05) the nitrogen retention. Mean nitrogen retention was I 82. 4.41, 7 .19 and 9.82 gld in wethers receiving diets A. B. C and D. respectively. Mean rumen ammonia concentration (mg N/lOO ml) in wethers receiving maize stovers. was 10.52. which increased (p< 0,05) to 17.87 in response to MUB supplementation. On lucerne hay. the rumen ammonia concentrations did not change due to MUB and the mean values on diets C and D were 24,24 and 29.88 mg N/100 ml. rcspectively. It was concluded that MUB supplementation did not affect in vivo dry matter or organic matter digestibility of the experimental diets. but was effective in supporting higher nitrogen retention. Diets based on lucerne hay supported higher nitrogen retention in wethers than those fed maize stovers. Feeding of MUB increased the demand for drinking water