The objective ofthis study was to identify and to correlate parameters that characterize pubertyand 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. Bloodsamples were collected from the jugular vein and centrifugated and the plasmawere stored at -20°C until analysis of progesterone (P4) concentrationby radioimmunoassay (RIA). The morphometric measurements included: head lengthand 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 concentrationwas >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 ofage) were lighter. The morphometric measurements has medium to low correlationswith age and weight at puberty.
