Qualitative indicators of sperm from producing goats before and after cryopreservation

Abstract

Currently, artificial insemination, as one of the types of assisted reproductive technologies, is widely used in dairy and beef cattle breeding. The same cannot be said about such a promising direction in the agricultural industry as goat breeding. One of the limiting factors is the negative impact of low temperature on the morphofunctional charateristics of sperm of breeding goats. The purpose of this research was to test a protocol of sperm cryopreservation of stud goats with modification of prepreparation and subsequent assessment of the quality indicators of sperm before and after its deep freezing. A comprehensive assessment of sperm quality (volume, concentration, morphology, motility) of goats (n=10) was carried out using generally accepted methods and protocols. The assessment of sperm quality indicators included five stages: after sperm collection, two hours after cooling, after thawing: 0 hours, 1 and 2 hours. According on the obtained results, the sperm of breeding goats ha low cryoresistance. After cryopreservation (0, 1 and 2 hours after thawing), there is an increase in the number of sperm with tail damage by 7.5% (p≤0.05), 15.5% and 21.8% (p≤0.01), and also a decrease in the number of progressively moving sperm by 1.4; 1.6 and 2.5 times (p≤0.01) compared with the results of the assessment 0 hours after collection. The use of a deep two-phase sperm freezing protocol allows maintaining the viability of sperm with a progression of movements equal to 54.2±5.1% and a number of morphologically normal sperm equal to 64.1±1.9%. In this case, the prepreparation of sperm for the cryopreservation process (current protocol) includes sperm centrifugation (mode: 7000 rpm for 15 minutes), removal of seminal plasma, dilution 1:4 (OptiXcell diluent), cooling (4 hours at 4℃); sperm cryopreservation protocol: 1. immersion of goblets with paillettes 4 cm above liquid nitrogen for 7 minutes; 2. complete immersion in liquid nitrogen.