Feeding dairy ewes with a diet containing agri-food co-products: Implications on rumen metabolism

In a worldwide context of increasing demand for animal-derived products, speculations of the feed market and climatic risks, sheep farming faces the daily challenge of ensuring its sustainability, while food by-products arise as alternative feeds, due to their nutritional value and wide availability. The aim of the present study was to evaluate the use of orange peels from a Greek orange juice industry as a high value secondary feedstuff for dairy sheep, within a circular economy approach. Enzymatically hydrolyzed (processed) and unprocessed orange peels were introduced to 2 groups (n=12/group) of dairy ewes of Chios breed at 11% DM inclusion levels (groups P & U), while group C of 12 ewes served as controls. All rations were isoenergetic and isonitrogenous and ewes were individually fed for 84 days. Milk production and composition were measured biweekly. Although fat corrected milk yield was significantly higher (p<0.05) between U and C treatments on Day 14 only, at most samplings milk fat of U group was significantly higher (p<0.05) than the C and milk protein was higher at all samplings for U group (p>0.05) . It appears that unprocessed orange peel feed could increase acetic acid production in the rumen, thus increasing milk fat content . In conclusion, orange peels could potentially be a promising secondary feedstuff that can be used as a sustainable alternative ingredient for dairy sheep nutrition.