Evaluation of scrotal circumference and testosterone levels at different ages of Gayo buffalo as local animal genetic resources

Abstract

The purpose of this study was to evaluate the scrotum circumference and testosterone levels at various ages of the Gayo buffalo. This study involved 10 Gayo buffalo with four different age groups I: (1.0–2.0), II (2.1–3.0), III (3.1–4.0), IV (4.1–5.0). Blood serum sampling, measurement of scrotal circumference, and age were carried out in Central Aceh regency. The analysis of blood serum testosterone levels was carried out in the physiology laboratory of the Faculty of Veterinary Medicine at Universitas Syiah Kuala. Data on testosterone levels, scrotal circumference, and age were analyzed for variance and continued with Duncan’s Multiple Range Test for data with significant differences. Simple regression analysis was used to determine the relationship between scrotal circumference, age, and testosterone levels. The results of the analysis in the age group and the concentration of the hormone testosterone showed significant differences (P <0.05). The age group of 3.1 to 4.0 years was significantly different from the age group of 1.0–2.0, 2.1–3.0 years, and 4.1–5.0 years. The results of the analysis on the scrotal circumference and testosterone concentration showed no significant difference (P>0.05) in various age groups. There was a significant relationship (P<0.05) between the concentration of the testosterone hormone with age and scrotal circumference, with a regression equation Y= 1.009-0.076X1+0.002X2, with a correlation coefficient (r) of 1 and a coefficient of determination (R2) of 1. These results indicated that scrotal circumference and age greatly influenced the concentration of the testosterone hormone of Gayo buffalo. The conclusion was that age affected the scrotal circumference, but it did not affect the concentration of the testosterone hormone. Gayo buffalo aged 3.1–4.0 and 4.1–5.0 years had a stronger correlation than Gayo buffalo aged 1.0–2.0 and 2.1–3.0 years to scrotal circumference and testosterone concentration.