Sperm parameters on Iberian red deer: Electroejaculation and post-mortem collection

Abstract

Artificial reproductive technologies (ART) for cervids have improved, but a need remains for the collection of basic data. We studied two models of sperm collection in Iberian red deer, post-mortem (PM) in a wild population (179 samples) and by electroejaculation (EE) in a farmed population (37 samples), recording: testicular and epididymal weight, testicular diameter, sperm quantity, pH and osmolality and spermatozoa quality (motility by CASA, abnormal forms, cytoplasmic droplets, viability and acrosomal status). We tested the relationship of these parameters with stag age and compared the two models (PM and EE; medians showed). Genitalia parameters were linearly related to stag age (testicular diameter: 31.5–50.5 mm for 2–9 years). Total number of spermatozoa collected were PM: 2.5 × 109 and EE: 3.6 × 109 (P > 0.05), increasing with age only for PM. We found a positive relationship between testicular size and spermatozoa collected for PM. Osmolality and pH were PM: 6.28 and 378 mOsm/kg; EE: 7.63 and 309 mOsm/kg (P < 0.05). The pH increased with age only for EE. Percentage of motile spermatozoa was similar for PM and EE, but motility quality was lower for PM. Abnormal forms, proximal and distal droplets were lower for EE (22%, 1.3%, 1.5% vs. PM: 23%, 4.3%, 83%). Viability was similar (74%) and intact acrosomes were higher for EE (97% vs. 89%). Both PM and EE samples could be used for germplasm banking. This study contributes with new data on red deer spermatology and for the development of ART in cervids.