Reproductive characteristics of Crioulo Lageano breed bulls (Bos taurus) at puberty

Abstract

The aim of this research was to evaluate pubertal development characteristics of Crioulo Lageano breed bulls (n = 10) using morphometric measurements and semen analysis, to identify factors that can be used to estimate age at puberty in this locally adapted breed. Monthly measurement of body weight and fortnightly measurement of scrotal circumference, chest girth, testicular length, width, thickness, and volume were recorded for each of the 10 Crioulo Lageano breed bulls, which were between 10 and 20 months old. During this period, semen samples were collected every two weeks using electroejaculation method and analyzed physically and morphologically. The ages of the appearance of first spermatozoa in the ejaculate (FSE), the first motile spermatozoa in the ejaculate (FSEM), seminal puberty (PUB) and total detachment between glans penis and prepuce (DPP) were ascertained. Crioulo Lageano bulls reached puberty at 14.1 ± 2.0 months old with lower weight and larger testicles than those of other bovine breeds. Similarly, the period from FSEM to PUB was shorter and the period from FSE to FSEM was longer than those reported for other breeds. The most important characteristics studied in order to estimate puberty age in Crioulo Lageano bulls were the measures of testicular length, width, and volume. These parameters can be used as criteria to select young bulls as sires.