Diet supplementation with hemp (Cannabis sativa L.) inflorescences: effects on quanti-qualitative milk yield and fatty acid profile on grazing dairy goats

: Hemp (Cannabis sativa L.) is an annual plant belonging to the family of Cannabaceae with several varieties characterized by different fatty acid profile, content in flavonoids, polyphenols, and cannabinoid compounds. Hemp is mostly used in livestock nutrition as oil or as protein cake, but not as inflorescences. The aim of this study was to evaluate the effect of dietary hemp inflorescences on milk yield and composition in grazing dairy goats. Twenty Camosciata delle Alpi goats at their 3rd parity and with a mean body weight of 45.2 ± 2.0 kg, immediately after kidding, were equally allocated into two groups (G: Grazing and GH: grazing and hemp). For three months, all goats were fed on a permanent pasture and received 700/head/day of concentrate; diet of group GH was supplemented with 20 g/head/day of hemp inflorescences. Goats' body weight did not change during the trial. Individual milk yield was daily recorded and samples collected every 20 days for chemical composition and fatty acid profile analysis. No significant differences were found for milk yield and chemical composition. Caproic (C6:0) (1.80 vs. 1.74%; p < 0.01) and lauric acids (C12:0) were significantly higher in milk of group GH (4.83 vs. 4.32%; p < 0.01) as well as linoleic (C18:2) (2.04 vs. 1.93%; p < 0.05), adrenic acid (C22:4) (0.046 vs. 0.031%, p < 0.05), omega-6/omega-3 ratio (3.17 vs. 2.93, p < 0.05) and total conjugated linoleic acids (CLAs) (0.435 vs. 0.417%; p < 0.01). The results of this study suggest that the supplementation of grazing goats' diet with hemp inflorescences may enhance the milk nutritional characteristics by increasing its content of CLAs and other beneficial fatty acids.