Effects of Energy and Mineral Supplementation on Nutrient Digestibility and Efficiency of Milk Production in Lactating Goats

Crossbred (Alpine x Beetal, Saanen x Beetal) lactating goats in their 2^nd and 3^rd lactation were fed with varying levels of energy and minerals through an isonitrogenous diet for a period of 120 days. The first two groups (E₁M₀and E₁M₁) received their normal levels of energy requirements and the rest two groups were supplemented with 20% more energy (E₂M₀ and -E₂M₁) as per NRC (1981). The diets E₁M₁ and E₂M₁ were supplemented with mineral mixture (30 g kg⁻¹ concentrate mixture). DM intake, which varied marginally (P>0.05), were 894.3±20.02, 855.1±27.64,957.4±73.79 and 976.7±43.67 g animal⁻¹ day⁻¹ in E₁M₀, E₁M₁, E₂M₀ and E₂M, respectively. Intake of OM and CP was higher (P<0.05) in E₂M₀ and E₂M₁ (954.3±19.52 and 913.7±45.12 g OM, 215.9±20.83 and 210.7±10.22 g CP animar⁻¹ day⁻¹ respectively) compared to E₁M₀ (844.7±13.39 g OM and 195.9±3.76 g CP animal⁻¹ day⁻¹) and E₁M₁ (795.1±25.18 g OM and 186.5±3.14 g CP animal⁻¹day⁻¹). Digestibility of OM, CP, NDF, ADF, hemicellulose and cellulose apparently improved (P>0.05) in the energy supplemented groups particularly in E₂M₀. N retention was higher (P<0.05) in E₂M₀ (13.45±0.57 g day⁻¹ animal”‘) and E₂M¹ (9.66±0.56 g day⁻¹ animal⁻¹) compared to that in E₁M₀ and E₁M₁ (7.71±0.27 and 6.94±0.75 g day⁻¹ animal⁻¹ respectively). Gross energy efficiency of milk production improved (P<0.05) in E₂M₀ and E₂M₁ (23.3±1.96 and 27.7±2.91% respectively) vis-a-vis that in E₁M₀ and E₁M₁ (15.9±1.69 and 18.6±2.45% respectively). Protein efficiency for milk production was lower (P<0.05) in E₁M₀ and E₁M₁ (19.6±2.25 and 19.1±4.53% respectively) in groups fed with normal level of energy. The highest (P<0.05) protein efficiency was observed in E₂M₁ (33.3±4.69%) and that in case of E₂M₀was 24.4±2.06%. However, the effects of supplemental minerals either alone or together with higher level of energy did not exihibit in the present study.