Factors Characterizing Puberty in Ram Lambs of Four Breeds Raised under High Altitude Conditions

Abstract

The aim of this study was to compare ram lambs of four Colombian wool breeds raised under high altitude conditions to describe evolution of semen characteristics, body development, and libido and plasma testosterone. Corriedale, Hampshire, Romney Marsh, and Creole rams were enrolled since the age of 4 months for libido and testosterone (maximum, mean and amplitude) assessment, whereas semen collection was performed between 6 and 11 months of age by use of electro-ejaculation. Beside analysis of variables in function of breed and over time, a semen maturity score, considering semen volume, mass motility, individual progressive motility, concentration and % of living spermatozoa was established in function of adult rams’ reference data. Colombian Creole displayed significantly higher results regarding all variables and showed the most important body development at each time point of the study.