Resumen de Performance, carcass characteristics, economic margin and meat quality in young Tudanca bulls fed on two levels of grass silage and concentrate

Emma Serrano Martínez, M. J. Humada, Irma Caro Canales, Ibán Vázquez González, Ana Olaizola Tolosana, Helena Resano Ezcaray, Sergio Soto Simental, Javier Mateo Oyagüe

• This study investigates the effect on performance, carcass and meat characteristics of increasing the forage level in the diet of fattening Tudanca young bulls using silage as the forage source as compared with a conventional ad libitum straw plus concentrate diet. Twenty two Tudanca young bulls were assigned to three different finishing diets: ad libitum grass silage plus ad libitum concentrate (GS-AC), ad libitum grass silage plus concentrate limited to a half of the intake of the ad libitum group (GS-LC), ad libitum barley straw plus ad libitum concentrate (Str-AC) and then slaughtered at around 11 months of age. GS-LC diet resulted in relation to GS-AC and Str-AC diets in lower (p≤0.05) average daily weight gain (750 vs 1,059 and 991 g/animal/day, respectively), lower (p≤0.05) carcass weight (133 vs 159 and 152 kg, respectively) and carcasses with slightly lower conformation scores. Although GS-LC diet allowed for a lower dependence on concentrate (372 vs 657 and 729 kg/animal, respectively), economic margin was similar for the two GS groups (-63.1 and -64.1 vs -91.8 €/head). The polyunsaturated/saturated fatty acid ratio was the lowest (p≤0.05) in GS-AC meat (the group showing the highest IMF levels) and the ratio n-6/n-3 was the highest (p≤0.05) in Str-AC meat. GS-LC meat showed higher collagen content and Str-AC meat presented higher cohesiveness, springiness and chewiness values. Results suggested that the substitution of straw by grass silage and the restriction of the concentrate level could be recommended for finishing young Tudanca bulls in indoors systems.