The effect of breed-production systems on the myosin heavy chain 1, the biochemical characteristics and the colour variables of Longissimus thoracis from seven Spanish beef cattle breeds.

The effect of breed-production system on the myosin heavy chain 1 (MHC-I), the biochemical characteristics and the colour variables of longissimus thoracis (LT) from seven beef breeds was studied: Asturiana de la Montaña (AM), Asturiana de los Valles (AV), Avileña-Negra Ibérica (A-NI), Bruna dels Pirineus (BP), Morucha (MO), Pirenaica (PI) and Retinta (RE) (Age at slaughter between 368 and 541 days; carcass weight between 249 and 334 kg). Significant differences between breed-production systems were found for all traits evaluated. LT from the MO, a rustic type breed, was the most oxidative (MHC-I, 39.3%; isocitrate dehydrogenase activity, 52 nmol min(-1) mg(-1); pigment content, 188.4 µg acid haematin g(-1)) and showed a low L* value (32.6) and high a* and C* values (24 and 27.2, respectively). In terms of meat colour (L* and a*) the canonical discriminant analysis separated the breeds into two groups, the AV, the PI and the A-NI (the lightest ones) from the AM and the MO breeds (the reddest and darkest) whereas the BP showed an intermediate position. The RE and the A-NI were distinguished from the others by their high intramuscular fat content. Meat colour was affected by the muscle biochemical traits in the breed-production systems studied.

Carcass and meat quality characteristics of immunocastrated male, surgically castrated male, entire male and female pigs.

The aim of the study was to evaluate the effect of immunocastration on meat and carcass quality compared with meat from females, entire and surgically castrated males. One hundred and eighteen (LandracexDuroc)xPietrain crossbred pigs were assigned to four experimental groups: entire males (EM), females (FE), surgically castrated males (CM) and vaccinated males (IM). Pigs were reared in two pens per sex and slaughtered at an average of 180 days of age. Carcass and meat quality characteristics such as testis size and length, fat depth, lean content, proportion of the carcass represented by each joint, pH, colour and intramuscular fat were evaluated. There was a significant reduction in the size of these sexual organs in IM compared with EM. CM and IM were fatter than FE and EM in the loin area but, in the ham area, CM was the fattest and EM the leanest, while IM and FE were in between. Intramuscular fat of IM (2.1%) was no different from the other sexes evaluated, although it was higher in CM (2.5%) with respect to FE (1.7%) and EM (1.8%). There was no difference between the IM and other treatment groups in meat quality. Regarding ours results we can conclude that from the point of view of meat and carcass quality the immunocastration could be a good alternative to the surgical castration.