Age, empty body weight and carcass composition at the same proportion of total carcass fat in Portuguese cattle breeds

Abstract

A total of 165 male animals from large, Alentejana (24), Mirandesa (24), Marinhoa (24), and small Portuguese breeds, Arouquesa (24), Barrosã (23), Maronesa (24) and Mertolenga (22), were serially slaughtered at three different weights. Large breeds were slaughtered at 400, 525 and 650 kg and small breeds at 300, 425 and 550 kg. Data were adjusted to a standard total fat proportion in the carcass that corresponds to the maximum subcutaneous fat concentration value commercially acceptable in Portugal. Though it took 30–60 days longer for the Alentejana to reach the same proportion of total carcass fat of the small breeds, this difference was not significant. Globally, the between breeds carcass composition tended to be homogeneous. Only the Mertolenga breed, with a 4.57 muscle:bone ratio, was significantly different of all other breeds. This reflects the reduction in bone of 19.6 g/kg of carcass weight and an increase of 20.9 g of muscle per kg of carcass. There was a significant difference of 8.8 g/kg between the Mertolenga and Alentejana, Mirandesa and Marinhoa, regarding intermuscular fat. There was also a significant increase of 6.4 g/kg in kidney knob and channel fat in the Mertolenga in relation to the Alentejana. The tendency for homogeneity between breeds in fat deposit proportions reflects the similarity of the respective regression coefficients.