Cactus-alfalfa blend silage as an alternative feedstuff for Saanen dairy goats: Effect on feed intake, milk yield and components, blood and rumen parameters

Abstract

The effects of substituting corn silage (CS) by cactus-alfalfa blend silage (CABS) on feed intake, milk production and composition, blood parameters, rumen fermentation parameters, and feeding behavior of dairy goats were examined here. The spineless cactus (Opuntia ficus Indica) was chopped and blended with alfalfa hay (66:34 % dry matter (DM) basis, respectively) and ensiled for 45 days. After determining the chemical composition of the ensiled material (31.4 % DM, 1.01 mcal/kg NEL, 12.7 % CP and 48.6 % NDF), it was used in feeding dairy goats. Eight Saanen dairy goats (43.5 ± 3.5 kg BW) were used in a replicated 4 × 4 Latin squares design (21-d period) and fed separated ration, which CS was replaced by levels 0 %, 10 %, 20 % and 30 % DM of CABS. Substitution of CS with CABS increased linearly ruminal propionic acid molar with the maximum point of 22.5 (mol/100 mol) and decreased linearly acetic acid and acetate to propionate ratio (P < 0.05). There was no significant difference observed for dry matter intake (DMI), nutrients apparent digestibility, average daily gain (ADG) and milk yield, except for milk composition for all the diets. There was a quadratic effect on milk protein percentage whit the maximum points of 3.83 % by feeding 30 % of CABS (P < 0.006). There was a quadratic effect on somatic cell count (SCC) of milk whit the minimum value of 4.72 (105 cell/ml) by feeding 30 % of CABS (P < 0.001). Feeding CABS decreased linearly the concentrations of butyric acid (C4:0) and significantly changed margaric acid (C17:0) in milk fat (P < 0.05). The results of this study indicated that CABS did not affect DMI, milk yield and feeding behavior. However, the increase in milk protein content and the reduction of SCC suggest a positive effect of CABS on improving mammary gland functionality. Therefore, CABS can serve as an alternative feedstuff up to 30 % on DM basis, especially in semi-arid regions, to replace CS in the diet of dairy goats.