J. agric. Sci., Camb. (1974), 82, 11-14 Printed in Qreat Britain Some carcass characteristics of commercial quality cattle in Mexico BY M. H. BUTTERWORTH, E. GARCIA AND E. L. AGUIRRE Institute Tecnologico y de Estudios Superiores de Monterrey, Department of Animal Science, Sucursal de Correos '</', Monterrey, N.L. Mexico (Received 5 March 1973) SUMMARY Little is known about the carcass characteristics of unimproved commercial (or 'Criollo') cattle although these still account for a large proportion of slaughter animals in Latin America. Data were collected from 52 commercial cattle in a commercial slaughterhouse in Monterrey, N.L. Mexico. They included carcass weight, length, total edible meat (car- cass fat was negligible), total bone and eleven typical Mexican cuts whose anatomical relations are described. The age of the animals was judged according to dentition and data were stratified using this criterion for analysis. Variations in total edible meat, which averaged 77-4%, were almost entirely accounted for by differences in body weight. Data are presented to indicate amounts of various cuts in the carcasses and some significant differences were demonstrated in values for these cuts among age groups; possible explanations for this were discussed. Prediction equations were calculated to relate total edible meat with the selected cuts and carcass weight and it was found that carcass weight gave the best prediction of total edible meat and could also be used to predict expected weights of individual joints with reasonable accuracy. INTRODUCTION a ^ so P resente( ^ equations for the prediction of total meat. The present paper presents more detailed Although unimproved commercial (or 'Criollo') data with respect to selected joints of the carcasses cattle are said to account for some 80 % of the total referred to in the previous publication, cattle population in Mexico and a proportionally high ratio in other Latin American and Caribbean countries, relatively few studies have been carried MATERIALS AND METHODS out with a view to collecting data on their carcass characteristics. This study was carried out in a commercial USDA Valdez & De Alba (1966) described the system inspected packing plant in Monterrey, N.L. Mexico, used in the slaughter house in Mexico City for Data were taken on 52 commercial quality bulls; classifying these animals and included data on these resembled Criollo cattle but several had a killing-out percentage. Munoz & Martin (1969) small amount (say J maximum) of Zebu breeding, compared Criollo with Santa Gertrudis and Brah- The animals in the present study came from poor man cattle and crosses of the three with respect to quality range and were not given any subsequent killing-out percentage, lean meat, marbling and alimentation. They were taken at random from tenderness. Temple et al. (1970) presented values cattle slaughtered during the normal running of for killing-out percentage of Criollo steers. the plant. They were starved for approximately Willis & Preston (1969) compared Criollo cattle 24 h before slaughter. All carcass weights wore with Santa Gertrudis, Brahman, Holstein, Brown taken after 24 h at a temperature of 3-4 °C. Swiss and Charolais with respect to killing-out Carcass length was measured from the anterior percentage, edible meat, excess fat, first-quality limit of the pelvic symphisis to the middle of the edible meat, percentage bone, conformation index anterior surface of the first rib. and meat:bone ratio. The system used for cutting was that which is In a preliminary report of the present study, traditional in Mexico and other parts of Latin Butterworth etal. (1969) presented data on carcass America and which is believed to have been weight, percentage of total meat and percentage of originally introduced by the Spanish. An anatomical total bone together with differences due to age and relation of the joints weighed in the present study