171 Testicular size in Peruvian alpacas (Vicugna pacos): correlations with bodyweight, and age
J. Chacón A , J. Villanueva C , W. Huanca C , A. Chacón-Obando A , B. Vargas A , M. Urviola B , S. Pablo-Caqui C , F. Huanca C and F. Rioja CA Research Program on Applied Animal Andrology, UNA, Heredia, Costa Rica
B Laboratorio de Fisiología Animal, Fac Medicina Veterinaria, UNA, Puno, Perú
C Facultad de Veterinaria, Universidad Nacional Mayor de San Marcos, Lima, Perú
Reproduction, Fertility and Development 35(2) 213-213 https://doi.org/10.1071/RDv35n2Ab171
Published: 5 December 2022
© 2023 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of the IETS
The assessment of testicular size is a critical step during the breeding examination, albeit in most species—including Alpacas—farmers and clinicians often overlook it, causing the permanency of undesirable males in the stock, thus impairing the herd’s productive efficiency. We aim to report the testicular measurements (TM) length, width, and depth of clinically healthy Vicugna pacos sires raised under standard conditions in the Peruvian highlands of the Puno region. A total of 309 alpacas (Huacaya n = 233 and Suri n = 76) were clinically inspected. The males (6.0 ± 3.3, 2–12 years old) (63.5 ± 9.3, 37.6–84.4 kg bodyweight [BW]) were placed at the CE-La Raya and CIP-Quimsachata (n = 168 and 141, respectively) in the Puno region. They were under the same feed management conditions, based on Gramineae (Festuca and Stipa), which prevails in the Puna highlands. No additional supplementation was provided. The scrotum was inspected visually and by palpation to determine left to right symmetry. Males were classified as symmetrical by visual inspection only if no differences were noticed in the TM assessed. TM were determined on left and right testicle separately only in symmetrical males using a calliper. T-tests for independent means were used to compare TM between the Huacaya and Suri breeds. Pearson correlation coefficients and paired t-tests were used to compare TM in left and right testicles in the same males. These correlations were also obtained between TM versus bodyweight and age. In addition, TM were assessed through a linear regression model that considered the fixed effects of breed, age, bodyweight, and the random within-male repeated effect of testicle (left vs right). A total of 253 males were symmetrical (81.87%) and 53 asymmetrical (17.15%). Furthermore, three males were found as unilateral cryptorchids. No significant (P > 0.05) differences among TM according to left or right testicle, breed, or location were found. BW and age had a significant effect (P < 0.0001) on the TM regardless of the breed or location. Correlations for BW and age versus testicular length, width, and depth were respectively 0.38 and 0.20, 0.39 and 0.26, and 0.44 and 0.19 (P < 0.0001). The higher correlations between BW versus TM compared to age versus TM resemble other species.
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