Production, composition, fatty acid profile and sensory traits of milk from goats fed crude glycerin from waste frying oils used in biodiesel production

•Goats fed crude glycerin from waste frying oils show decreased intake and milk production.•Crude glycerin from waste frying oils does not affect the sensory attributes of the goat milk.•Crude glycerin from waste frying oil supplementation improves the milk FA profile.•Crude glycerin from waste frying oils in goats’ diet improves AI and elongase enzyme activity. Eight Anglo-Nubian goats with 42.06 ± 3.5 kg body weight (BW) and 51 ± 4.0 d in milk were randomly assigned in a double 4 × 4 Latin square experiment with 20-d periods and four diets with different concentrations of crude glycerin (0, 70, 140 and 210 g/kg on DM basis) to evaluate the effects on intake and on production, composition, fatty acid (FA) profile and sensory traits of milk. The inclusion of crude glycerin from waste frying oils in the goat diets linearly decreased the intake of DM (P=0.001), NDF (P