Cooled storage of semen from livestock animals (Part II): Camelids, goats, and sheep

Effect of the donor's age and type of extender (egg yolk versus clarified egg yolk) over the sperm quality of Majorera bucks preserved at 4°C: In vitro results and fertility trials

“…Previous studies developed in the same breed (Batista et al., 2011, 2014) showed practically similar values in sperm motility of stored semen at 4°C for 24–48 hr and were comparable when the sperm quality was assessed in chilled semen, whether the diluent used was based on egg yolk (Tabarez et al., 2017) or skimmed milk (Mocé et al., 2020; Sadeghi et al, 2020; Salvador et al., 2006) with medium values between 50% and 65% for the first 48 hr of chilling. In our study, sperm motility was reduced after 72 hr of storage, regardless of the diluent used or the age of the males; as a general rule, as the preservation time increases, a decrease in sperm motility is observed, probably as a consequence of metabolic depletion of sperm (Bashawat et al., 2021), being a fact to take into account, in order to reach an adequate fertility rate. Although the kinetic parameters of sperm motility were not assessed in our study, the subjective assessment showed that the spermatozoa moved more easily probably due to the lower number of particles present in the CEY extender, and, consequently, the spermatozoa found fewer obstacles and moved, apparently, quickly.…”

“…as a general rule, as the preservation time increases, a decrease in sperm motility is observed, probably as a consequence of metabolic depletion of sperm (Bashawat et al, 2021), being a fact to take into account, in order to reach an adequate fertility rate. Although the kinetic parameters of sperm motility were not assessed in our study, the subjective assessment showed that the spermatozoa moved more easily probably due to the lower number of particles present in the CEY extender, and, consequently, the spermatozoa found fewer obstacles and moved, apparently, quickly.…”

“…In addition, no significant differences were observed between extenders and bucks (young versus mature). Usually, these parameters did not change during the cooling procedure (Bashawat et al, 2021;Batista et al, 2011Batista et al, , 2014, suggesting that the storage at 4 °C did not increase the development of sperm abnormalities and the sperm viability does not change substantially, when the semen is refrigerated for a few days. However, the percentage of spermatozoa with membrane intact acrosomes showed a similar behaviour to the sperm motility, without detecting differences based on the extender used or the donor´s age.…”

“…Semen preservation in bucks has become a basic tool for reproduction technology, but its success is directly linked to many quality factors such as semen quality, type of extender quality or sample handling during the semen preservation. It is necessary to decrease the metabolism of spermatozoa, just before the cooling or freezing of semen, and so, adding substances to protect it from cold shock is necessary (Bashawat et al., 2021). The aim of adding extenders to semen is to create a protective atmosphere, where plasma‐membrane functionality, spermatozoa motility and acrosome integrity remain unchanged (Allai et al., 2018; Memon et al., 2013; Salvador et al., 2006).…”

“…Fresh egg yolk is a common component in sperm preservation media, basically used to prevent cold shock, but some components of seminal plasma may interact with egg yolk substances (Salamon & Maxwell, 2000; Tabarez et al., 2017). Buck semen present lipases secreted by the bulbourethral glands, and it has been defined a toxic interaction causing coagulation of egg yolk and hydrolyses lecithin to fatty acids and spermicidal lysolecithins that inhibit the motility of spermatozoa, producing toxic substances and reducing its freezing ability (Bashawat et al., 2021; Leboeuf et al., 2000). For this reason, the procedure of semen preservation in bucks is more complex than in other species and usually, and sperm washing by centrifugation is usually done in order to remove the seminal plasma (Paulenz et al., 2005; Salvador et al., 2007).…”