Ram and buck management

Changes in Sexual Behaviour and Semen Quality Associated with Age and Type of Enclosure of Saint Croix Rams in Different Seasons of the Year

“…In hair sheep, natural breeding is carried out throughout the year. The rams used in this study exhibited acceptable libido and sexual behaviour under different temperature and environmental conditions all year round (Sánchez-Dávila et al, 2011;Ridler et al, 2012). Consequently, it is necessary that rams show an effective sexual activity according to age and the relationship between their breeding capacity and sexual orientation, because this translates into high conception and lambing rates throughout the breeding year (Stellflug et al, 2006;Ridler et al, 2012;Sánchez-Dávila et al, 2012).…”

“…The rams used in this study exhibited acceptable libido and sexual behaviour under different temperature and environmental conditions all year round (Sánchez-Dávila et al, 2011;Ridler et al, 2012). Consequently, it is necessary that rams show an effective sexual activity according to age and the relationship between their breeding capacity and sexual orientation, because this translates into high conception and lambing rates throughout the breeding year (Stellflug et al, 2006;Ridler et al, 2012;Sánchez-Dávila et al, 2012). In general, fertility is higher and more efficient when ewes are exposed to rams that exhibit better sexual behaviour, leading to higher conception rates in comparison with ewes exposed to ram lambs (4-6 months) exhibiting poor sexual behaviour and variable semen quality (Stellflug and Lewis, 2007;Ungerfeld et al, 2008;Alexander et al, 2012).…”

“…Photoperiod (Delgadillo et al, 2009), availability of food supplements during critical seasons (Scaramuzzi et al, 2006) and low forage production in semi-arid regions due to climatic conditions (Sánchez-Dávila et al, 2011) play an important role in the productivity of the various species. Consequently, efficient reproduction in males should be enhanced through an adequate understanding of environmental factors, such as climate, nutrition and health, since they influence male fertility in different seasons of the year and under different reproductive management methods, such as continuous or controlled breeding (Stellflug et al, 2008;Ridler et al, 2012). It has been reported that seasonality of hair sheep is not as marked as in wool breeds (Godfrey, 2005;Valencia and Ledezma, 2005;Valencia et al, 2006;Uthlaut et al, 2011).…”

“…It has been reported that seasonality of hair sheep is not as marked as in wool breeds (Godfrey, 2005;Valencia and Ledezma, 2005;Valencia et al, 2006;Uthlaut et al, 2011). In summer, a decrease in semen quality (Martín et al, 2004;Ridler et al, 2012), scrotal circumference, testicular weight, and sexual behaviour is observed in wool rams living in latitudes higher than 40° (Ungerfeld et al, 2007). Their sexual behaviour is completely inhibited due to the lack of gonadotropin hormone support (Ungerfeld et al, 2007;Sanford and Dickson, 2008), thus affecting the capacity to induce oestrous in ewes (Stellflug et al, 2006).…”

Seasonal variation in semen quality of Dorper rams using different collection techniques

“…When addressing the problem, the element of seasonality is a factor to be considered, as sheep are seasonal breeders and this ultimately affects the semen quality (Hafez & Hafez, 2000;Senger, 2003). In sheep, a decrease in daylight length is known to increase the rate of spermatogenesis, owing to the production of melatonin, which ultimately stimulates the release of the gonadotrophin-releasing hormones (GnRH) (Leahy et al, 2010;Ridler et al, 2012). Greyling & Grobbelaar (1983) have reported that little information is available about the seasonal fertility of rams (including the Dorper) throughout the year in South Africa.…”