Abstract

The objective was to determine the variation in the number of thoracolumbar (TL) vertebrae and its effect on size and weight of the carcass, as well as weight of joints in Suffolk lambs. The vertebral number was determined by means of radiographs in 51 lambs, and its formulas by means of the thoracolumbar sum. The carcasses were weighed at slaughter, the joints and the zoometric measurements were made the following day. There is variation in the thoracolumbar number with respect to the ancestral number TL19, finding TL20 and TL21, observing 4 different formulas, one ancestral T13L6 (19.6%), and three multivertebral T13L7 (70.6%), T14L6 (5.9%) and T14L7 (3.9%). TL21 (T14L7) lambs produce carcasses 4.4 kg heavier and 6.14 cm longer than TL19, and 3.9 kg heavier and 5.24 cm longer than TL20. The weights of the carcass joints of multivertebrae lambs were heavier than those obtained from those with ancestral number.