Frozen Semen Quality
In continuous attempt to improve quality of frozen semen, NLBC in the past has brought about many changes in laboratory practices and will continue to improve further in future also. Following are the major changes introduced in the laboratory with an aim of improving the semen quality.
1. Bull Rearing:
- Screening of bulls against diseases (Brucellosis, TB, FMD, Campylobactor etc).
- Maintaining health and hygiene of the bulls regularly.
- Regular drenching of bulls against external and internal parasites.
2. Semen Collection
- Use of bull apron to prevent contamination.
- Collecting semen from a bull twice a week and only two ejaculates with an interval of minimum thirty minutes on the day of semen collection.
- Maintaining hygiene at collection yard and introducing the new Dummy Cow for the collection.
- Collection of semen through use of SMILE technology
- Use of double distilled rain water or water from water mili-poor water filtration instead of single distilled tap water.
- Use of ready made egg yolk free semen extender (Non Biological base made in France and Jermany) from FY 2012/13.
- Change of buffer from tri-sodium citrate to tris.
- Addition of egg-yolk and antibiotics in the morning of collection day instead of previous evening.
4. Semen Evaluation
- Regular use of photometer to determine sperm concentration.
- Reduction of sperms per dose of semen from 40000000 to 20000000.
- Evaluation of semen through CASA System.
5. Semen Processing
- Single step extension instead of phased extension.
- Use of masks, gloves etc and increased laboratory sanitation.
- Filling, Sealing and Printing of semen straws by IS-4, Genom'x (France) and Quattro automatic filling and sealing Machine (Jermany) which is great change for this lab.
6. Quality control
- Checking post thaw semen motility 48 hrs after freezing before storage.
- Periodic checking of post thaw viability.
- Checking of bacterial load in laboratory and semen.
- Periodic Hypo-osmotic Swelling test to check sperm cell integrity
- Periodic Live-dead count of frozen semen.
- Use of separate mother referees for storing individual bull semen.
- Counting of semen straws in LN2 while transferring.
- Counting semen straw in LN2 during distribution.
- Allotment and rotation of bulls for different regions to prevent inbreeding.