PRODUCTIVE BEHAVIOR OF MEVEZUG LAMBS IN NATIVE GRASSLANDS DURING THERAINY SEASON, IN TIERRA CALIENTE GUERRERO, MEXICO

The objective of the study was to determine the average daily weight (ADG), carcass hot performance (CHP) and the weight of some viscera of MEVEZUG lambs grazing in native grasslands during the rainy season (June- September) of 2016. Eighteen lambs with an average weight of 221.9 ± 4.2 kg were used. The animals grazed 10 hours daily, from 9 am to 7 pm. The animals were weighed every 21 days, in four times, after a previous fast of 12 hours. The statistical analysis included the determination of mean, standard deviation and coefficient of variability. The daily weight gain of the animals was 95.2 ± 19.45 g, with 55.6% of lambs with weight above average. The following numbers were found in the weight of lambs slaughtered, in the carcass and CHP: 27.17±5.2g, 10.39±2.2 kg and 38.12 ± 1.2, respectively. The contents of the compartments of the gastrointestinal tract of the lambs were 6.017.5 ± 1.155.9 kg, and represented 22.23 ± 2.2% in relation to the live weight. The weight of the organs was 98.83 ± 14.8 g, 72.8 ± 14.2 g, 206.9 ± 150.5 g, 502.1 ± 121.0 g and 7.67 ± 5.3 g, for heart, kidneys, liver and gall bladder, respectively. The weight of the fat was 24.0 ± 11.49 g, 8.9 ± 4.05 g, 75.33 ± 72.6 g, 206.9 ± 150 g for mediastinal, pericardial, perirenal and abdominal. The primary sections of the canal recorded the following percentages: 23.5 ± 1.7 for the legs, 22.1 ± 1% for the spine and 20.7 ± 1.3 for the rib. It is concluded that the daily weight gain was in a higher range than those reported in the grasslands production system and similar to when supplemented with energy sources. The CHP and viscera weight was similar to that reported in other work on grazing lambs in native grasslands