The effect of season on the scrotal circumference and sperm motility and morphology in rams

Effect of Heat Stress on Buck’s Adaptability and Semen Characteristics

“…Similar results were also found by El-Darawany Curtis (1983) and El-Darawany (1999) for the scrotal skin temperature of sheep. Mikelsen et al (1981) recorded the greatest scrotal circumference measurements during the autumn season. Yarny et al (1990) claimed that scrotal circumference and testis length in hot summer in sheep decreased to the extent that they became lower than those of the same breeds reared under temperate environmental conditions.…”

Variations saisonnières du diamètre testiculaire et de la morphologie des spermatozoïdes chez le bélier Vendéen et chez le bélier Texel

“…In the V breed, no significant variations appeared at any time of the experiment, except in the last month when BW decreased (P < 0.05). However, Thibault, 1956 ;Ortavant, 1958 ;Pelletier, 1971 ;Albério, 1976 ;Colas, 1980Colas, , 1981 (Colyer, 1971 ;Courot, 1971 ;Albério, 1976) En plus du pourcentage total d'anomalies morphologiques, nous avons calculé la proportion de spermatozoïdes porteurs de malformations de la tête (lésions de l'acrosome, micro-ou macro-céphalies, têtes pyriformes ou allongées etc...), connues pour leur effet sur la fécondance (Colas, 19811 et (Ortavant et Thibault, 1956 ;Ortavant, 1958, Pelletier, 1971Albério, 1976 ;Schanbacher, 1979 ;Schanbacher et Ford, 1979 ;Lincoln, 1979 ;Colas et al, 1985) (Fowler, 1965 ;Neves, Günzel et Schmidt, 1980 ;Colas, 1980 ;Mickelsen, Paisley et Dahmen, 1981 ;Amir et al, 1986).…”

Changes in semen quality and morphology of the reproductive tract of the male tammar wallaby parallel seasonal breeding activity in the female

“…As in other mammals, spermatozoa acquire the capacity for motility in the epididymis in the tammar (Jones et al 1984, 1988, Jones 1989 and motility increases as the number of structurally mature spermatozoa increase in the corpus and caudal regions (Jones et al Semen quality and seasonal breeding in the male tammar wallaby 373 1984). In many seasonally breeding eutherians, increased testosterone levels and testis and epididymis size in the breeding season are accompanied by improved sperm morphology and increased sperm motility (Mickelsen et al 1981, Brown et al 1991, Monfort et al 1993, Smith et al 1999, Goeritz et al 2003. Thus, in the tammar it is likely that elevated testosterone in the breeding season(s) results in an increase in the proportion of functionally mature and highly motile spermatozoa.…”

“…In the Southern hairy-nosed wombat and in many eutherian species, season has a distinct influence on semen volume and quality. Seasonal variation in these characteristics is positively correlated with plasma testosterone levels and the size of testes and accessory glands (Mickelsen et al 1981, Brown et al 1991, Monfort et al 1993, Swanson et al 1996, Smith et al 1999, Ciereszko et al 2000, Goeritz et al 2003. Thus, high quality semen is associated with increased circulating testosterone and enlarged testes and accessory sex glands during the breeding season.…”