Evaluation of Complete Diets with Different Levels of Deseeded Sunflower Heads and Concentrate by in vitro and in situ Techniques

Sixteen complete diets were formulated using sunflower heads (SFH) as sole roughage source or in combinations with sorghum straw (SS), sugarcane bagasse (SB) and maize cobs (MC) in four roughage concentrate ratio of 20:80, 30:70, 40:60 and 60:40. The crude protein (CP) in the diets containing up to 40% roughage was similar among all the diets (15.48 to 17.49%) except for lower (P<0.01) CP in diet containing 20% MC and 20% SFH (14.74%). The CP content reduced as the roughage content in diets increased beyond 40%. The ash content in diets was higher (P<0.05) when SFH was present as sole roughage. Incorporation of SB increased (P<0.01) the fibre content in diets, while it was reduced when SFH was present as sole roughage. Such differences in fibre content with regard to source of roughage disappeared at higher roughage (60%) concentration. The neutral detergent and acid detergent fibre content were similar among all the diets. The in vitro organic matter (IVOMD) and neutral detergent fibre (IVNDFD) digestibilities ranged from 50.40 to 69.49% and 11.84 to 52.35%, respectively. The roughage source was not affecting the IVOMD in diets containing either 20, 30 or 40% roughage, but at higher roughage concentration (60%) the IVOMD was higher in diets containing 50% SFH or 40% SFH in combination with MC. The IVNDFD lowered (P<0.01) as the SS or SB increased in diets beyond 10%, but such effect was not observed when SFH was present as sole roughage (20–40%) or at 50% level along with 10% SS. Similarly, the effective DM degradability (EDMD) was higher (P<0.01) when SFH was present as sole roughage source (69.04%) compared to other dietary combinations. The EDMD% was highest (P<0.05) for diet containing 50% SFH (69.70%) followed by diets with 40% SFH as sole roughage (69.04%). From the results it can be inferred that SFH can be incorporated in complete diets either as sole roughage source at 40% level or at 50% level in combination with 10% sorghum straw.