No abstract

-A comparison was made of the distribution of bone, muscle, subcutaneous fat and intermuscular fat (g of tissue in the joint per kg of the respective tissue in the carcass) at the same proportion of total carcass fat for a total of 165 animals from three large (Alentejana (n = 24); Mirandesa (n = 24); Marinhoa (n = 24)), and four small, (Arouquesa (n = 24); Barrosã (n = 23); Maronesa (n = 24) and Mertolenga (n = 22)) Portuguese breeds, serially slaughtered at three different weights. The distribution of muscle was significantly different across breeds in a larger number of joints than either the distribution of bone, subcutaneous fat or intermuscular fat. However, the range of differences in each joint was narrower for muscle. So, amongst the first class joints (leg, sirloin, ribs and fore ribs), only the sirloin and the fore ribs, both with a range across breeds of only 7 g·kg -1 , were significantly different between breeds. On the contrary to subcutaneous fat, the proportions of intermuscular fat tend to decrease, particularly in the leg. As expected, the joints with homogeneous parameters were the most accurate for predicting the proportion of muscle (g·kg -1 ) in the carcass from the proportion of muscle (g·kg -1 ) in the joint. For the large breeds, the most accurate joints were the leg and the coast, with a residual s.d. of 13.91 g·kg -1 and 18.45 g·kg -1 , respectively; and for the small breeds the most accurate joints were the fore ribs and the leg, with a residual s.d. of 15.35 g·kg -1 and 17.11 g·kg -1 , respectively. The difference between the actual breed means and the means predicted using the overall equation for each of the most accurate joints were lower than ± 4 g·kg -1 for all breeds with the exception of the Barrosã with a value of -8 g·kg -1 . distribution / joints / carcasses / beef cattle Résumé -Répartition des tissus dans les carcasses de bovins de races autochtones portugaises. Une étude comparative a été menée sur la répartition des tissus osseux, musculaires, adipeux sous-cutané et adipeux intermusculaires (g de tissu dans le morceau par kg de tissu respectif dans la carcasse) pour une même proportion de gras total. Au total 165 animaux, comprenant des races de grande taille : Alentejana (n = 24), Mirandesa (n = 24), Marinhoa (n = 24), et des races de petite taille : 287 Anim. Res. 52 (2003) Arouquesa (n = 24), Barrosã (n = 23), Maronesa (n = 24) et Mertolenga (n = 23), ont été séquentiel-lement abattus à 3 poids différents. Le muscle était le tissu dont la répartition a été significativement différente entre les morceaux, mais où l'amplitude des différences entre races, pour chaque morceau, a été plus étroite. Parmi les morceaux de première catégorie, seuls l'aloyau et l'entrecôte, tous deux avec une amplitude de 7 g·kg -1 , ont été significativement différents entre les races. Comme attendu, les morceaux avec des paramètres de régression homogènes ont été les plus précis pour prédire la proportion de muscle (g·kg -1 ) dans la carcasse à partir de la proportion de muscle (...

No abstract