Nutrient intake and digestibility of selected browse plants fed in combination with Panicum maximum to West African dwarf (WAD) bucks

Abstract

A study was conducted to evaluate nutrient intake and digestibility of Panicum maximum fed in combination with selected browse plants to West African dwarf (WAD) bucks. Four intact West African dwarf (WAD) bucks of mean body weight 17.50kg were used to conduct digestibility study in a 4 x 4 Latin Square design experiment. Four forage combinations, diets A, B, C and D were fed to the goats. Diet A, the control, was 100% Panicum maximuni, while diets B, C and D contained 60% Panicum maximum each plus 40% of Alchornea cordifolia, Manniophyton fulvum and Gmelina arborea, respectively. The study lasted 56 days in a 14 day x 4 change over periods. Data were collected on dry matter intake (DMI), nutrient intake and digestibility. Simple linear regression and correlation were used to assess the degree of relationship between some of the digestion components. The result of proximate analysis indicated that the diets (P. max + browse) B, C and D had significantly (p<0.05) higher dry matter (%DM) contents of 81.12, 81.09 and 80.68%, respectively, than the 75.71% for diet A (sole P.max). Crude protein content of 17.56, 15.62 and 17.52%, respectively were also higher (p<0.05) than the 8.38%for diet A. There was higher (p<0.05) ether extract content of 2.43, 2.38 and 2.32%, for diets B, C, and D, respectively than the 1.32% for diet A. The ash content of 10.71, 9.78 and 9.76% for diets B, C and D respectively, were also higher (p<0.05) than the 7.83% for diets A. Metabolizable energy (MJKg-1) values of 1.41, 1.42 and 1.42 for diets B, C and D were also higher (p<0.05) than the 1.31 for diet A. However, the crude fibre value of the diet A (27.26%) was significantly (p<0.05) higher than the 18.30, 19.30 and 18.58% for diets B, C and D. respectively. There were significant (p<0.05) differences in DMI among treatment means. Vitro significantly (p<0.05) higher for animals fed diets B(15.04). C(13.12 ) and D(14.48 ) wherein P.max was fed in combination with browse plants than in the diet A( 6.28) group fed sole Pmax. Faecal nitrogen showed no significant (p>0.05) difference among treatment means. Urinary nitrogen was significantly (p<0.05) higher in diet A group (0.39) than in diets B (0.30), C (0.34) and D (0.43) groups. There was positive nitrogen balance for all in the treatment groups. Apparent nitrogen digestibility (%) was significantly (p<0.05) higher in diets B (92.37). C (90.51) and D (97.63) groups than in diet A (79.49). Nitrogen intake (g/d) could not reliably predict faecal nitrogen (g/kgDM) in diets C and D groups. Absorbed nitrogen (g/d/WKg0.75) could not predict urinary nitrogen (g/d/WKg0.75) in any of the diets. Biological value (BV) of the diets were A (55), B (45), C (81) and D (97). The result of this study shows that the animals fed P. max + browse recorded higher DMI, nutrient intake and digestibility than the sole P.max diet. These evaluation indices were, however, mostly better in the diet B group (60% P.maximum + 40% Alchornea cordifolia). The combination of 60% P. maximum + 40% Alchornea cordifolia is therefore recommended for West African dwarf (WAD) goats reared in the humid tropics of Nigeria for optimum intake and improved nutrient utilization.