Reproductive characteristics of captive male jaguars (Panthera onca)

Abstract

Ejaculate traits, testicular volume and plasma testosterone levels were determined once every two months for one year in 4 adult male jaguars (Panthera onca) housed at the São Paulo Zoo, SP, Brazil. Semen samples was collected by electroejaculation and analyzed for pH, total volume, motility (0-100%), status (0-5), total spermatozoa count and morphology. Blood samples was obtained by cephalic venipuncture immediately before the onset of electroejaculation and stored at -20ºC until assay of testosterone by RIA. Using a calliper, the length and width of each testis was measured and the values were combined to determine the testicular volume. Semen analyses demonstrated a high percentage of structurally abnormal sperm (mean = 51%) and low rates of motility (50.6%) and status (2.2). No correlation was found between semen traits, plasma testosterone and testicular volume (Spearman’s test). No season variation was detected throughout the year for semen traits, plasma testosterone and testicular volume (p>0.05, Friedman’s test). The results of this study suggest that the captive jaguars in Brazil are not seasonal, and that semen collections can be performed throughout the year without a perturbation in overall ejaculate quality. However, underlying causes of high percentages of structurally abnormal sperm, found in captive jaguars, need to be investigated mainly to improve semen quality.