Artificial Insemination - Anatomy & Physiology
Introduction
Artificial insemination involves:
- Collection of semen from the male
- Preservation and extention of sperm
- Insemination of the female
All dairy cattle and a large proportion of beef cattle in the UK are bred by artificial insemination. It is also common practice in Turkeys, Pigs and Horses. Success rates are very dependent on good insemination technique, which can be carried out by an inseminator service or DIY. Generally, success rates are the same or better than natural survice.
Semen Evaluation
- Determine ejaculate volume.
- Estimate the percentage displaying progressive motility (linear motion) at 37◦C.
- Determine sperm concentration.
- Total sperm in ejaculate = ejaculate volume x sperm (ml)
- This determines how many insemination doses are possible from each ejaculate.
- >60% motile sperm = good quality
- <50% motile sperm = discard, especially if it is intended to be frozen
Seminal Extenders
- Extend the number of sperm in the original ejaculate.
- Extend the life of sperm.
- Must be isotonic
- Must minimize cold damage.
- The cell membrane of spermatozoon is sensitive to sudden drops in temperature 'cold shock'.
- Slow, controlled cooling of sperm is important because it minimizes stress on the cell membrane by lowering temperatures gradually.
- A low storage temperature reduces metabolism by about 50% for each 10◦C decline.
- Enables conservation of their fixed amount of metabolic energy.