Hempseed By-Product in Diets of Italian Simmental Cull Dairy Cows and Its Effects on Animal Performance and Meat Quality.

Cull dairy cows are important contributors to total beef production in the USA and in Europe. Hempseed cake is a by-product of oil production and it is rich in unsaturated fatty acids (FA). This study aimed to investigate the effect of adding hempseed cake to the diet of Italian Simmental (IS) cull dairy cows on performances and meat quality. Twenty-six cull dairy cows were divided into three dietary groups: hay-based, corn silage-based and pasture-based diets. Within each group, the animals were equally divided into two treatments according to the protein source of the concentrate: hempseed cake (HEMP) or soybeans meal (SB). The trial lasted four months. HEMP showed similar in vivo performance and carcass characteristics, such as average daily gain ( p > 0.05) and dressing percentage ( p > 0.05), compared with SB. Meat characteristics, such as ether extract content and Warner-Bratzler shear force, were also similar between experimental groups ( p > 0.05). Considering FA composition, HEMP showed similar saturated FA and polyunsaturated FA content ( p > 0.05) but lower desirable fatty acids ( p < 0.05) content and a tendentially lower hypocholesterolemic/hypercholesterolemic ratio ( p < 0.10) than SFA. Hempseed cake can substitute soybean in the diet of cull dairy cows without effects on performance or meat quality.