Semen characteristics of a ram population in southern Spain: An on-farm program of elimination of low-fertility males diagnosed by electroejaculation

Abstract The objective of this study was to identify and exclude rams that presented signals that might indicate low fertility in a program to improve the profitability of sheep farms within a large sheep cooperative in Spain. The study involved 966 rams of 10 breeds on 45 farms, and ram examinations were performed from Sep 2017 to Jan 2019. A breeding-soundness examination (BSE) and semen collection by electroejaculation (EE) was performed on each ram. Genital alterations, morphological or pathological injuries, and minimum thresholds for semen motility, volume, and concentration were factors that led to the exclusion of a ram. Among the rams in the study, 805 (83.5%) were classified “suitable”, 130 were declared “failed” (13.5%), and 29 (3%) were deemed to be borderline case and required a re-examination. Sperm quality (substandard semen quality, total azoospermia, or necrozoospermia) was the primary reason for the exclusion of a ram (82.4%). Testicular abnormalities, were responsible for 12% of the rams excluded. Mean body condition score (BCS), ejaculate volume, and scrotal circumference (SC) did not differ significantly between suitable and failed rams; however, on average, failed rams were older, had lower sperm concentrations and mass and individual motilities than did suitable rams (P