Relación entre el peso vivo, la circunferencia escrotal y las características seminales en corderos Pampinta durante el desarrollo puberal: Relationship between live weight, scrotal circumference, and seminal characteristics in Pampinta lambs during pubertal development

There is limited information regarding pubertal development in Pampinta breed males, despite the importance of this breed in sheep production systems in Argentina. The objective of this study was to describe changes in live weight, scrotal circumference, and seminal characteristics during the growth of Pampinta lambs, and to analyze their relationship with the onset of puberty. The study was conducted at three farms in La Pampa province using 45 male lambs born during the second half of August 2025. The animals were evaluated at approximately 60, 90, 130, 140, and 200 days of age. At each evaluation, live weight and scrotal circumference were recorded; once preputial separation had occurred, semen was collected via electro-ejaculation to determine ejaculate volume, mass motility, individual motility, and sperm concentration. Puberty was defined as the production of an ejaculate with a minimum concentration of 50 × 10⁶ spermatozoa/mL and individual progressive motility ≥10%. Scrotal circumference increased from 22.4 ± 1.8 cm to 34.7 ± 1.2 cm between 60 and 200 days of age, paralleling the increase in live weight. At the end of the experimental period, the animals had an average weight of 56.76 ± 7.09 kg, an average scrotal circumference of 32.54 ± 2.90 cm, and a sperm concentration of 726.6 ± 201.3 × 10⁶ spermatozoa/ml. The average age at the onset of puberty was approximately 188 days, at which point the animals exhibited seminal parameters consistent with the beginning of reproductive capacity. The results indicate that the reproductive development of Pampinta lambs is closely associated with body growth and that scrotal circumference serves as a practical indicator for monitoring puberty and the early selection of future breeding rams.