Conservation of Ha Giang highland cattle breed by frozen semen and artificial insemination

One study aimed at producing frozen semen pellets with a post thawing progressive motility of 35% or more, was undertaken in Dong Van, Meo Vac, Quan Ba districs - Ha Giang province from March 2007 and November 2007. Five bulls ageing 30-40 months old, weighing 350 kg/head, with normal reproductive organs and a high libido, were chosen for the study. Two medium: VCN (medium 1) and Thai binh Research Centre (medium 2) were used. After training, semen was collected and checked for volume, color, smell, progressive motility, sperm concentration, morphology, pH) Frozen semen after thawing was also checked for the progressive motility. It was shown that four of five bulls chosen met the standard of breeding bulls according to Vietnamese standard of semen quality for breeding bulls (TCVN2002). Volume, concentration of collected semen, and abnormal rate of sperm in collected semen were 3.87ml/ejaculation, 84.9, 11.9% respectively. After dilution, the progressive motility was high and no different between medium 1 and medium 2 (P>0.05). After equilibration, the progressive motility was changed slightly (P > 0.05) and ranged from 37.48 to 37.58% after thawing. The pregnancy rate of the first AI examined at 90th day was 68,2% (n = 22). (Résumé d'auteur