Testicular biometrics of Murrah buffaloes in different age groups

Knowledge of the testicles’ biometric parameters is fundamental to performing an andrological evaluation of a breeder. The present study was conducted to determine Murrah buffaloes’ testicular biometry. Twenty-four buffaloes were classified into three age groups: G1 (15 to 19 months), G2 (20 to 23 months), and G3 (>24 months), located in Montelíbano, Córdoba, Colombia, from March to November 2022. The measurements analyzed were scrotal circumference (SC), spermatic cord circumference (CC), Testicular volume (TV), Testicular length (TL), and width (TW). To measure the TL, testes were measured, excluding the epididymal tail in the dorsal-ventral direction. In contrast, TW was measured in the middle portion of each testis in the lateral-medial direction. The TV was determined using the equation of the spheroid prolate and represented the average of both testes. Descriptive statistics were performed for each variable; for the SC and TV, a linear regression model as a function of age and weight was analyzed, and simple Pearson correlations were performed. The mean values observed for G1, G2, and G3 were SC (21.7 ± 2.2.0 cm; 24.2 ± 1.2 cm and 27.4 ± 1.2 cm), CC (18.3 ± 2.7 cm; 20.0 ± 2.7 cm and 25.7 ± 2.1 cm), TV (79.7 ± 41.6 cm3; 142.2 ± 32.8 cm3 and 220.7 ± 39.5 cm3), right TL (6.8 ± 1.7 cm; 8.2 ± 0.8 cm and 9.0 ± 0.4 cm), left TL (6.7 ± 1.7 cm; 8.2 ± 0.8 cm and 9.0 ± 0.5 cm), Right TW (3.5 ± 0.5 cm; 4.2 ± 0.3 cm and 5.0 ± 0.4 cm) and left TW (3.4 ± 0.5 cm; 4.2 ± 0.2 cm and 5.0 ± 0.3 cm). The average weights of the groups were: G1 (350.0 ± 27.6 kg), G2 (387.9 ± 45.6 kg), and G3 (469.3 ± 40.1 kg). Positive and significant correlations of weight and age were found with SC (R: 0.86 and 0.90, respectively), as well as with TV (R: 0.85 and 0.87, respectively). From the linear regression models, the estimated monthly variations were for 1.16 ± 0.01 cm (p<0.01), and the TV grows by 8.2 ± 0.3 cm3 (p<0.01). In addition, it was estimated that, for each kilogram of live weight that the animal gains, the SC grows 0.05 ± 0.00 cm (p<0.01) and TV 0.42 ± 0.1 cm3 (p<0.01). Some testicular biometry parameters typical of the Murrah breed were known, and the variations concerning age were identified. In addition, it was possible to estimate the relationship with body weight, which will allow us to establish precision and comparison of testicular development models. More studies are necessary to standardize the morphofunctional changes of buffaloes chronologically.