Effect of breed and finishing diet on growth parameters and carcass quality characteristics of Navarre autochthonous foals

This research was conducted to study the effect of breed, Jaca Navarra (JN) vs. Burguete (BU), and finishing diet, conventional concentrate—diet 1 vs. silage and organic feed diet 2—on growth parameters and carcass characteristics from forty-six foals. Parameters as live weight (LW), average daily gain (ADG), body condition score (BCS), and fat depots were monitoring. In addition, the carcass parameters assessed were: carcass weight (CW), conformation, degree of fatness, morphology, and pH. Moreover, hindquarters of the left-half carcasses were sectioned in the main commercial primal cuts of leg. Results showed a clear “breed effect” in favor of BU foals, recording the highest productive values and carcass traits compared with JN foals. On the other hand, finishing diet contributed to improving the productive and carcass features of JN foals. In particular, diet 1 showed to affect positively the features analyzed compared with diet 2. Nevertheless, the meat primal cuts resulted in being unaffected by the breed and diet effects (except for knuckle), obtaining similar values among the groups of animals.Interreg V SUDOE | Ref. SOE2 / P5 / E0804Universidad Pública de Navarra | Ref. 787/2019CYTED | Ref. 119RT056

Efecto del peso de sacrificio sobre la composición de la grasa de corderos de raza lacha

Due to the fact that domestic consumers prefer low fat meat, the lamb production system in Spain is based on slaughtering low weight animals (12 to 24 kg). Lambs in other European countries are slaughtered at higher weights because consumers prefer more intense flavored and fatter meat. Based on evidence that slaughter weight affects fat characteristics, the effect of slaughtering weight on the fatty acid profile of omental (OM), mesenteric (MES), kidney knob (KK), subcutaneous (SC), intermuscular (IN) and intramuscular (IM) fat in Lacha breed lambs was studied. Forty–two male Lacha lambs were raised and slaughtered at 12 (L12), 24 (L24) and 36 kg (L36) live weight. L12 lambs were fed only on mother's milk until slaughter, one month old. L24 and L36 lambs were fed ad libitum on commercial feed and barley straw from weaning (around 16 kg live weight) until slaughter. Adipose tissue samples were taken at the slaughterhouse, vacuum–packed, frozen and stored. Fatty acid methyl esters were analyzed by capillary gas chromatography, and the relative amounts were recorded. The results were analyzed using ANOVA and Tukey's test (p<0.05). Concentrations of C12:0 and C14:0 decreased after weaning due to the fact that the lambs no longer ingested mother's milk. In all fat depots, L24 showed the highest saturated fatty acid concentration, mainly due to the higher C18:0 content. An increase in C18:1n–9cis in heavier lambs (L24 to L36) was observed, associated to fat reserve accumulation processes. The analysis of these data suggests an increase in desaturation enzymes activity among higher–weight lambs, when ruminal activity was initiated. The most suitable n–6/n–3 and polyunsaturated/saturated ratio in muscle fat for preventing cardiovascular disease were observed in L24 lambs.Debido al hecho de que los consumidores domésticos prefieren carne baja en grasas, el sistema de producción de corderos en España se basa en el sacrificio de animales de bajo peso (12 a 24 kg). Los corderos en otros países europeos se sacrifican a pesos mayores porque los consumidores prefieren carne de sabor más intenso y con más grasa. Debido a que el peso del sacrificio afecta las características de grasa, se estudió el efecto del peso de sacrificio de corderos de raza Lacha en el perfil de ácidos grasos de la grasa omental (OM), mesentérica (MES), pelvicorrenal (PVR), subcutánea (SC), intermuscular (IN) e intramuscular (IM). Cuarenta y dos corderos machos de raza Lacha se criaron y sacrificaron con un peso vivo de 12 (L12), 24 (L24) y 36 (L36) kg. Los L12 se alimentaron únicamente con leche materna hasta su sacrificio, a un mes de nacidos. Los corderos L24 y L36 se alimentaron ad libitum con alimento comercial y paja de cebada desde el destete (alrededor de 16 kg de peso vivo) hasta el sacrificio. En la planta de sacrificio (matadero) se tomaron muestras de tejido adiposo; se empacaron al vacío, se congelaron y se almacenaron. Se analizó los ésteres metílicos de los ácidos grasos por cromatografía de gases capilar y se registraron las cantidades relativas. Los resultados se analizaron usando ANDEVA y la prueba de Tukey (p<0.05). Las concentraciones de C12:0 y C14:0 disminuyeron después del destete debido a que los corderos ya no consumían la leche de la madre. En todos los depósitos de grasa, L24 mostró la concentración más alta de ácidos grasos saturados, principalmente debido al mayor contenido de C18:0. Se observó un aumento en C18:1n–9cis en corderos más pesados (L24 a L36), asociado a los procesos de acumulación de reservas de grasa. El análisis de estos datos sugiere un aumento en la actividad de enzimas de desaturación en los corderos de mayor peso, una vez iniciada la actividad ruminal. La tasa más adecuada de n–6/n–3 y poliinsaturado/saturado en grasa muscular para prevenir la enfermedad cardiovascular se observó en corderos L24