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.