Effects of anthelmintics and supplementation on productivity of Menz and Menz-Awassi crossbred sheep with sub-clinical helminthosis

Abstract

A total of 108 weaned Menz (n=39), 50% Awassi X Menz (n=38) and 75% Awassi X Menz (n=31) sheep genotypes of two sexes were randomly allocated into two nutrition levels (supplemented and non-supplemented) and two anthelmintic treatments (treated and untreated) to investigate their differential response to natural sub-clinical helminthosis on-station at Debre Berhan, Ethiopia. Data were collected on feed intake, live weight (LWT), eggs per gram of faeces (EPG), packed cell volume (PCV), fleece weight (FWT), slaughter weight (SLWT), carcass weight (CWT), dressing percentage (DP), and adult worm burden counts (WB) with worm identification. Anthelmintic treatment reduced EPG and WB and this was consistent with the higher PCV (31.6 vs. 27.4%; p<0.0001) for treated than for non-treated sheeThis, in turn, was reflected on higher (p<0.05) LWT, SLWT, and CWT in treated than for non-treated sheeEPG of Strongyle and egg prevalence of Fasciola and Trichuris as well as WB of F. hepatica and Trichostrongylus colubriformis for treated sheep was significantly lower (p<0.05) than for non-treated sheeSupplementation had no significant effect on TPG and WB counts. However, supplemented lambs enormously improved (p<0.0001) ADG, SLWT, CWT, and DBreed difference (p<0.0001) was observed in dry matter intake (DMI); the intake of 75% Awassi X Menz sheep being highest compared with 50% Awassi X Menz and indigenous Menz sheeMenz rind its 50% cross with Awassi were able to maintain their PCV and had higher DP in spite of their relatively higher parasite load than the 75% AwassixMenz genotype. Significant interactions were treatment by nutrition for LWT and SLWT, breed by treatment for PCV, LWT and ADG, and breed by nutrition for LWT and total DMI. Supplementation and strategic anthelmintic treatment could be used to maintain high-grade sheep genotypes under sub-clinical parasitism in the highlands of Ethiopia