Valorisation of spent coffee grounds as functional feed ingredient improves productive performance of Latxa dairy ewes

Abstract

Spent coffee grounds (SCG) represent one of the main residues derived from restoration and hostelry. The aim of this study was to evaluate the effect of SCG, included in the concentrate at different concentrations (0, 30, 50 and 100 g/kg), on milk yield and quality, feeding behaviour, dry matter intake, apparent digestibility and ruminal short chain fatty acid profile. In this trial of 51 days of duration, 48 Latxa dairy ewes were used. The ewes were blocked in quartets according to milk yield (1918 ± 287 g) and days in milk (35.7 ± 8.9 days). All of the concentrates were formulated to be isoenergetic (1.01 UFL), isoproteic (166 g/kg), isofat (76 g/kg) and to meet the production needs. The concentrate was given in two doses of 450 g of dry matter during the morning and afternoon milkings, and fescue hay was offered ad libitum. Milk production was recorded and samples were taken for fat, protein and lactose composition analysis. Dry matter intake and apparent dry matter digestibility were estimated using two markers, and feeding behaviour data was recorded. Increasing doses of SCG in the concentrate up to 100 g/kg resulted in a linear (P < 0.001) increase in the rumen of the isovaleric and isobutyric acid contents which could explain the observed quadratic response (P < 0.001) in milk yield and a linear increase (P < 0.001) in milk protein. A linear increase (P < 0.001) in milk fat was found which could be explained by the observed linear increase (P < 0.001) in ruminal acetic and butyric acid contents. Increasing doses of SCG in the concentrate linearly decreased ruminal (P < 0.001) propionic acid content, resulting in a concomitant linear increase (P < 0.001) in acetic:propionic ratio. Furthermore, no differences were found in intake, apparent dry matter digestibility and feeding behaviour. In conclusion, inclusion of SCG up to 100 g/kg in the concentrate modified ruminal fermentation pattern towards an increase in isoacids and acetic and butyric acid contents in the rumen with a concomitant improvement in milk production and composition without impairing feeding behaviour or apparent digestibility.