Growth performances and meat quality of Maremmana growing bulls fed grain legumes

The effects of dietary inclusion of lupine and faba bean throughout the growing and finishing periods were evaluated in Maremmana bulls raised in an extensive organic farm (Bracciano, Roma). Twelve young bulls (7.7±0.29 months; 241±13.8 kg BW) were allotted into two groups. The control group was fed farmer's diets based on meadow hay, straw, maize silage and a mixture (50/50) of barley and maize meal. The experimental group was fed diets in which barley/maize meal was substituted by growing and finishing concentrates containing lupine and faba bean (on average, 7.5 and 30.5%, respectively). The average forage/concentrate ratio were, respectively for control and experimental diets, 61/39 vs 60/40, Meat FU 0.75 vs 0.69/kg DM, CP 8.7 vs 12.8% DM. Animals were weighed at the beginning of the trial and thereafter every 2 months until prefixed slaughtering age (21 months). Metabolic profile was measured at month 9 and 12 of experimental period. Meat quality assessment (i.e. chemical composition and collagen content, colour, drip and cooking loss, shear force on raw and cooked meat) was performed on 7-day aged Longissimus thoraci. ADG was analysed by a mixed model for repeated measures including the effects of diet, time and the interaction diet*time. The effect of diet on metabolic profile, carcass traits and meat quality were analysed by one-way ANOVA. Carcass score was compared by the Kruskal-Wallis test. Legume fed animals showed higher (P<0.05) ADG (960 vs 1230 g/d, SE 0.44), slaughtering weight (637 vs 746 kg, SE 22.4) and carcass weight (310 vs 395 kg, SE 22.8) than control animals. No differences were observed for metabolic profile, slaughtering traits and carcass scores. Meat quality was not affected by diet, except drip loss (0.9 vs 1.2; SE 0.06; P<0.01). Results suggest that use of legumes in diets for Maremmana growing bulls may be an advantageous choice for animal performance, without detrimental effect on meat quality