Weight and age at puberty and their correlations with morphometric measurements in crossbred breed Suffolk ewe lambs

The objective of this study was to identify and to correlate parameters that characterize puberty and estimate the age and weight of Suffolk ewe lambs in Mato Grosso do Sul. This study was carried out with twenty-two Suffolk ewe lambs for 256 days. Blood samples were collected from the jugular vein and centrifugated and the plasma were stored at -20 degrees C until analysis of progesterone (P-4) concentration by radioimmunoassay (RIA). The morphometric measurements included: head length and width, body length, elbow height, chest perimeter, back-sternal diameter, croup length, width and height, cannon bone perimeter and shoulder and hip width, using a tape. The animals became pubertal when the plasma progesterone concentration was > 1.0 ng/mL, at 34.1 +/- 5.2 kg and 39.5 +/- 8.5 weeks of age. Meanwhile, the lambs that did not reach puberty (37.7 +/- 11.4 weeks of age) were lighter. The morphometric measurements has medium to low correlations with age and weight at puberty.