Dietary inclusion of restaurant food waste effects on nutrient digestibility, milk yield and its composition, blood metabolites of lactating Zaraibi goats, and their offspring performance

This study aimed to evaluate the effects of rations containing restaurant food waste (RFW) on nutrient digestibility, milk yield and its composition, and some blood parameters of lactating Zaraibi goats. In the last month of pregnancy, 30 goats (32.8 + 0.91 kg body weight and aged 3–4 years) were chosen and divided into three similar groups (10 goats per group). Each group was randomly assigned to be fed one of the experimental rations. The control group (R1) fed on a ration comprising concentrate feed mixture (CFM1) and berseem as a fresh roughage whereas the second (R2) and the third groups (R3) fed on CFM partially substituted by 15 and 30% of RFW (CFM2 and CFM3, respectively). Nutrient digestibility and feeding values were improved with R3 goats, which had the highest level of RFW (30%) versus R2 and R1 goats. The total volatile fatty acid (TVFA) concentration in the in-rumen liquor was elevated by increasing the level of RFW up to 30% in CFM3 of R3 goats. Actual daily milk yields were significantly (P < 0.05) higher (1269.30 g/h/d) for R3 goats versus R1 and R2 (1037.57 and 1180.70 g/h/d, respectively). The inclusion of RFW in rations had a significant effect on the yield of milk constituents, without significant different among experimental rations regarding some blood constituents and offspring performance. Economic feed efficiency (relative feed cost and relative daily profit) was improved by including RFW in the CFM. Therefore, it can be concluded that the inclusion of up to 30% RFW improved productive performance and economic efficiency in lactating Zaraibi goat rations.