STUDY ON FROZEN-SEMEN SPERM CHARACTERISTICS OF BREEDING BULLS AND THEIR FERTILITY RATE IN FIELD LEVEL

Abstract

Artificial Insemination (AI) is a convenient means of improving livestock productivity and improving the return on investment in livestock. The success of AI program mostly depends on post thaw quality of semen . The main object of semen quality test is to ensure the fertility of sperm present in semen sample. Semen quality and its relation to fertility are major interest in animal production. However, frozen sperm characteristics in relation to field fertility have not been explored extensively. The objective of this study was to assess the relationship between frozen thawed-semen sperm characteristics (motility, viability and abnormality) and fertility rate in the field level of Sylhet district. For this purpose, frozen semen of four genetic groups was collected from District Artificial Insemination Centre, Sylhet. Field fertility information was collected from AI record book. The motile sperm estimated by individual motility.To evaluate sperm viability and abnormalities eosin-nigrosin staining was used. The highest mean value of post-thaw sperm motility, viability were found 52.75±0.37%, 72±0.42% in SL breed and highest mean value of abnormal spermatozoa found 19.75± 1.02% in LXFXFXF breed. A significant variation was found in semen parameters among four genotypic bulls after thawing. Sperm motility and abnormality appeared to be significantly different (P<0.05) among four genotype, while live sperm percentage did not vary significantly. A total of 400 inseminations were performed in cows by different AI technician in Sylhet district, Sylhet. Fertility rate attained in a single insemination was recorded on the basis of rectal palpation at day 60 after insemination. Individual pregnancy rate of 54%, 59%, 62% and 65% were found in the frozen thawed semen of SL, LXF, LXFXF, LXFXFXF genotype respectively. A significant negative correlation (r=-0.71; P<0.0001) was reported between sperm motility and fertility.