Abstract
The aim of this study was to evaluate parameters indicative of sperm quality of fresh and post-thawed semen of Aberdeen Angus, Holstein and Nelore bulls. Thirty-nine bulls were used: Aberdeen Angus (n=13), Holstein (n=13) and Nelore (n=13). The ejaculate collects were performed twice a week using artificial vagina, totaling 792 semen collections, 307 for Aberdeen Angus, 225 for Holstein and 260 for Nelore bulls. After collection, fresh semen was evaluated and semen freezing was performed. After freezing, the batches were thawed and progressive motility was determined. The analysis of fresh semen showed that there was no difference (P = 0.053) between the Aberdeen Angus and Nelore breeds, while ejaculates from Holstein bulls showed a statistical difference (P = 0.024). As well, a difference (P<0.001) was identified in the sperm concentration of the three breeds. In the samples evaluated after thawing, a statistical difference was observed between Holstein and Nelore breeds (P<0.001), while the values of the Angus breed were similar to the other two breeds. The difference in motility of fresh and post-thawing semen showed that Nelore and Angus bulls showed greater variation in values between the analyzes (26.0±8.9% and 25.3±8.4%, respectively) showing a significant difference (P<0.001) in relation to Holstein bulls (20.6±9.3%) that obtained the smallest difference. The analysis of fresh and post-thawing semen did not show any significant difference (P=0.13) between breeds. In conclusion, the semen cryopreservation process causes a decrease in the physical parameters of the semen and these quality losses suffer interference according to the breeds.
Highlights
Reproductive biotechnologies are used to accelerate production, increase reproductive efficiency, and promote genetic improvement in the herd
The semen cryopreservation process causes a decrease in the physical parameters of the semen and these quality losses suffer interference according to the breeds
Regarding the sperm characteristics evaluated in fresh semen, it was possible to observe that for the motility parameter there was no significant difference between the bulls breeds (P = 0.053)
Summary
Reproductive biotechnologies are used to accelerate production, increase reproductive efficiency, and promote genetic improvement in the herd. The cryopreservation process can cause damage to sperm, which reflect a decrease of approximately 50% of sperm motility (Celeghini et al, 2007; Thomas et al, 1997). The negative effects on sperm after thawing are notable, such as decreased motility due to changes in mitochondrial function, damage to the plasma membrane and acrosome (Layek et al, 2016; Ntenka et al, 2016), sperm cryopreservation has the advantage of storage for indefinite periods and providing worldwide distribution (Layek et al, 2016). In order to obtain good results in the use of artificial insemination, rigorous quality processes are necessary, from the management of breeding bulls to the stages of collection and cryopreservation of the semen, taking into account that the process of the semen cryopreservation causes a drop in sperm quality (Abud et al, 2014; García-Álvarez et al, 2014). It is essential to select breeding bulls capable of producing cryopreservation-resistant ejaculates and maintaining high sperm viability and fertilizing capacity after thawing (Ntenka et al, 2016; Queiroz et al, 2015; Ram et al, 2017)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
