Breeding Soundness Evaluation in Alpaca (Vicugna pacos) Males: A Long Retrospective Study of the Effects of Cystic Masses and Environmental Temperatures on Scrotal Measures

Male alpacas have reproductive peculiarities that can influence the breeding soundness evaluation (BSE). This study was aimed to analyse the frequency of epididymal and testicular cystic lesions in alpacas (Vicugna pacos) retrospectively during different environmental temperatures. A total of 45 subject from 120 males were evaluated with linear probe (10 MHz; MyLab VetONE) between at 5 different alpaca farms in Italy. Semen was collected via artificial vagina and semen parameters were evaluated. Twenty % (9/45) of the males demonstrated the presence of abnormal testicular and epididymal cyst. Those cystic lesions could represent a simple result of drainage defect of the fluid produced (ectasia of the rete testis), congenitally derived from a probable hereditary pattern (2/9) or affecting epididymal structures (3/9). Cystic lesions can increase the scrotal volumetric asymmetry due to the most common mono -lateral lesions (P<0.05). Some diagnostic biochemical parameters such as the seminal plasma alkaline phosphatase was higher in affected males (P<0.05). Besides, environmental temperature can influence scrotal swelling independently by the presence of cystic lesions thus alter the scrotal volume. The ultrasonography can provide more specific information about the presence of epididymal and testicular anomalies influencing the BSE results.