ABSTRACT
Physicochemical characteristics were determined in the longissimus lumborum muscle, after 8 days of ageing of steers (n=12) and bulls (n=12) from Mertolenga breed slaughtered directly from pasture (day 0) or after a finishing period of 50, 100 and 150 days in a feed-lot facility. Bulls and steers presented similar live weight (averaging 388 kg), carcass weight (CW; averaging 213 kg), dressing percentage (averaging 60%), carcass fatness (11.9% CW) and carcass fat thickness (averaging 3.03 mm). Live weight, CW, carcass fatness and fat thickness increased along time-on-feed. Gender only had a negligible effect on meat characteristics, with b and h being the only parameters of colour affected by gender, also presenting a significant interaction gender × time-on-feed. Nevertheless, both the genders presented a high-quality grade concerning tenderness (Warner-Bratzler shear force (WBSF)). L increased until 50 days on feed and decreased afterwards, whereas a and C values increased along time-on-feed. Pigment content was also affected by time-on-feed and showed a gender × time-on-feed interaction. Beef colour became darker and redder along time-on-feed, but still in a colour range highly acceptable by Portuguese consumers. Despite the increase in intramuscular fat and myofibrillar fragmentation index, as well as the decrease in collagen content of steers and bulls along time-on-feed, it did not affect the tenderness/hardness, indicating a small effect of time-on-feed in meat characteristics. Despite only small differences in carcass characteristics and meat-quality parameters that have been noticed along time-on-feed, those differences were only significant after 100 days on feed. Principal component analysis (PCA) was performed. The first PC axis (39.6% of the total variance) included colour variables a, b and C, and carcass fatness, fat thickness, CW and live weight, whereas the second one (12.7% of the total variance) included h, cooking losses and dressing-out. The principal component (PC) analysis confirmed the lack of differences between bulls and steers and indicates a differentiation of the first two periods of feeding (0 and 50 days on feed) from the two latter (100 and 150 days on feed) periods of feeding.
Subject(s)
Animal Feed , Animal Husbandry/methods , Cattle/physiology , Meat/standards , Animal Nutritional Physiological Phenomena , Animals , Body Weight , Breeding , Male , Muscle, Skeletal/chemistry , Muscle, Skeletal/metabolism , Orchiectomy/veterinaryABSTRACT
Three quality branded meats (n=68), "Vitela Tradicional do Montado"-PGI veal, Mertolenga-PDO veal and Mertolenga-PDO beef were analysed for cholesterol (HPLC-UV), α-tocopherol (HPLC-FD), fatty acid composition (GC-FID), including conjugated linoleic acid (CLA) isomeric profile (Ag+-HPLC), and nutritional value of lipids. All the meats analysed had similar contents (P>0.05) of cholesterol, α-tocopherol and intramuscular fat. In contrast, the percentage of 18:0 was lower for PGI veal, and that of 18:1 c9 was higher in PDO veal, whilst the percentage of 18:2 n-6 was higher in PDO beef, relative to other two meats. The content of total CLA and the percentage of its t11,c13 isomer were higher, and the n-6/n-3 ratio was lower, in PDO veal, relative to the other two meats. The data suggested that PGI veal has higher variability for most fatty acids than the other two types of meat. Finally, a discriminant analysis was conducted and the three meat types were well discriminated using the meat fatty acid profile as variables.
