Effect of feeding slow-release bolus of zinc, selenium and cobalt on growth performance and some blood metabolites of Markhoz male goats

This trial was conducted to evaluate the effects of slow-release bolus containing zinc, selenium and cobalt on growth performance and blood parameters of Markhoz male goats for 60 days. Eighteen Markhoz male goats, 15 months of age with average weight of 24.4±5.1 kg were randomly divided into 2 groups (9 goats per group) including: 1) control group (basal diet without any mineral supplements and slow-release bolus and 2) bolus group (basal diet one slow release bolus). The dry matter intake, average daily gain and feed efficiency were determined. Blood parameters were measured on days 30 and 60. Daily feed intake was similar among treatments. Daily weight gain (37.41 gr/day), plasma concentrations of vitamin B12 (185.05 IU/L) and Zinc (0.86 mg/L), the activity of serum alkaline phosphatase (167.31 IU/L) and whole blood glutathione peroxidase (261.28 IU/gr Hb) and serum T3 level (1.35 nmol/L) were lower in control group than group receiving bolus (P