Influence of dietary exogenous fibrolytic enzymes on wool characteristics of sheep fed high roughage based total mixed ration

Addition of exogenous fibrolytic enzymes (EFE) in high roughage based ruminant diets can improve their feeding value and thus animal performance. The present study aimed to assess the effect of EFE cocktail inclusion in the diet of sheep on wool quantitative and qualitative characteristics and economics. An in vitro experiment was carried out to evaluate the effect of graded increasing levels (0.00, 0.20, 0.40, 0.60, 0.80 and 1.00% substrate dry matter) of EFE inclusion in total mixed ration (TMR) of sheep (each in six replicates) on nutrient degradability parameters. The results revealed the effective level of EFE inclusion in TMR for optimal nutrient degradability was observed at 0.60% (p = 0.001). The in vitro assay was followed by an in vivo experiment in which a feeding trail was conducted for three months on 12 number of crossbred (HampshirexFec-B gene carrying strain) male sheep distributed uniformly into two equal groups: control fed basal TMR only and the treatment group fed basal TMR added with EFE cocktail at 0.60% (as top), the level chosen on basis of the best results of in vitro assay. A digestibility trial by total collection method of 6 days collection period was carried out in last fortnight of the feeding trial after which the animals were shorn to quantify the wool yields from each sheep. Fibre qualitative characteristics and production economics of wool were also evaluated. The animals of both the group had similar feed intake (81.26 vs 76.90 g DM/kg W0.75/day), digestible nutrient contents (9.98 vs 10.70% digestible crude protein, 59.02 vs 65.30% total digestible nutrients) and their intakes except TDN intake (p<0.05) of 515.51 vs 616.22 g/d in control and treatment group, respectively. Significantly (p<0.05) higher digestibility of crude fibre and nitrogen free extract was recorded in treatment compared to control group. In wool quantitative parameters, greasy as well as clean wool yield were higher (p<0.05) in treatment compared to control group, while skirting yield, total wool yield, wool production per day, fleece weight index and feed conversion to wool were not affected. Likewise, wool qualitative characters were comparable between the two dietary treatment groups; however, the values tended to be better for animals fed EFE cocktail added TMR. Cost of wool production ($/kg) lowered numerically to the tune of 18.15% with the profit of 0.29 $ per animal for market sale price of wool yield in treatment compared to control group. It was concluded that incorporation of 0.60% EFE cocktail in basal TMR of sheep resulted in economical benefits through higher wool production with no adverse effect on quality characteristics.