Age at puberty in Obispo Creole lambs from La Montaña of Guerrero, Mexico

Abstract

Objective. Determine the age and body weight at the onset of puberty in Criollo Obispo lambs from a sheep herd. Materials and methods. The present study was carried out ex situ (18⁰ 15’ 52’’ LN). 10 lambs born during the spring were used, which were detected at 3 m of age. The detachment of the urethral process was verified at the age of 5.0 to 5.5 months of age. A semen sample was taken every two weeks with the help of an electro-ejaculator. Sperm concentration was evaluated with a digital photometer, while light microscopy was used for progressive motility and sperm morphology. The Kaplan-Meier procedure was used to estimate the risk or survival time function.to determine the days of onset of puberty. A male is considered to have entered puberty when the ejaculate registers at least 150 million sperm per mL, with a minimum of 50% abnormal cells and a motility greater than 30%. Results. It was observed that the average age of onset of puberty was 211.4±25.09 d, with a body weight of 19.3±1.27 kg. Conclusions. Criollo Obispo lambs begin puberty at 7 m of age and with a body weight of 19.3±1.27 kg.