EVALUATION OF SEMEN QUALITY, FREEZABILITY AND FERTILITY OF HOLSTEIN BULLS UNDER EGYPTIAN NEWLY-RECLAIMED LAND CONDITIONS | ||||
| Veterinary Medical Journal (Giza) | ||||
| Volume 54, Issue 1, January 2006, Page 7-28 PDF (8.62 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/vmjg.2006.379735 | ||||
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| Author | ||||
| E EL-HASSANEIN* | ||||
| Animal and poultry production Division, Desert Research Center, Cairo, Egypt. | ||||
| Abstract | ||||
| The objective of this study was to evaluate semen quality, freezability and field fertility of five Holstein bulls used for Al under Egyptian conditions. Spermiogram and freezability of raw semen collected twice weekly at a frequency of two ejaculates in succession were assessed throughout a full-yeas. Tris-yolk, skim milk-yolk and citrate yolk extenders were used for dilution either in one of two-steps to achieve a final concentration of 30 x 106 motile sperm/ml. Diluted-equilibrated semen was packaged in 0.5 mi French straws and frozen on nitrogen vapor (at -100°C for 15 minutes) before plunging into liquid nitrogen for storage Samples of each semen batch were thawed at 40 C for 30 seconds and incubated at 37°C for assessment of motility and sperm acrosomal, head and tail defects after 0 and 3 hours of incubation post thaw Field inseminations were conducted in small wale (25 cows), medium-scale (20-50 cows) and large scale (200-500 cows) breeder farms using as insemination doses proven to have minimal values of post-thaw progressive motility and sperm normalcy of 60 and 70 %, respectively. Spermiogram of raw semen was significantly (P< 0.01) affected by the “prevailing temperature. Ejaculate volume and sperm concentration, motility and normality decreased in semen collected in hot summer months, however, the extent of dead cells increased. Semen collected in hot months revealed a poorer freezability (P< 0.01) compared to that collected in cooler months. Dilution in citrate-yolk extender significantly (P< 0.01) improved sperm freezability compared with dilution in Tris-yolk or skim milk-yolk. Glyccrolation after a sufficient holding period at 5°C with egg-yolk r lipoproteins significantly improved sperm freezability. Semen collected in hot months revealed the least post-thawing sperm longevity (P< 0.01) | compared to that collected in cooler months. Dilution in citrate-yolk extender significantly (P< 0.01) improved post-thawing sperm livability compared with dilution in Tris-yolk or skim milk yolk. Post-thawing sperm longevity significantly = (P< 0.01) improved in semen glyccrolated at 5°C. A Total 6063 field first-inseminations revealed an overall conception rate (non-return rate % within 60 days) of about 60% however a significant (p<0.01) difference in conceptions had recorded between the three types of breeder-farms. The least conception (39%) recorded in the small-scale breeder-farms, While the best conceptions (71%) recorded in the large-scale ones. Hormonal control of estrus before AI significantly (P<0.01) improved fertility by about 32% compared to insemination of cows observed standing natural heat. | ||||
| Keywords | ||||
| Holstein bulls; semen; spermiogram | ||||
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