TABLE OF CONTENTS
Semen Evaluation Techniques in Animals: Precautions, Parameters & Quality Assessment Tests
Semen evaluation techniques are a series of diagnostic tests and assessments used to determine the quality, viability, and fertility potential of semen. The semen examination is of great diagnostic value in determining the cause, severity and degree of pathological conditions of the testes and other genital organs.
The quality of the semen can be useful in assessing the fertility of a male animal and it vary only in narrow limits between different ejaculates of a bull.
During adverse conditions the semen quality will be affected at a very faster rate but the recovery takes a longer time.
The semen is a highly fragile material. The semen quality should be assessed immediately after collection.
Once the sample is received inside the laboratory, it should be kept in a water bath of 37°C and evaluation should be started.
There are several parameters are available to assess the semen quality. The good quality semen will have better fertility but the poor quality semen will have poor fertility.
There are combination of tests are used to assess the semen quality. There is no any single test available to certify a semen sample.
Precaution to be taken to Maintain Semen Quality
The artificial vagina (AV) or containers used for semen collection should be clean and free from contaminants that might injure sperms such as alcohol, excessive petroleum jelly, and powder present on new liners and antiseptics and chemicals of any kind.
At the time of collection excessive dirt and debris should be kept out of AV water and urine adversely affects sperms. Excessive blood and serum also affect the semen quality.
Immediately after collection the semen vial should be placed in a water bath at 37°C. Overheating and rapid chilling of semen should be avoided as it affects the semen quality.
Too much agitation and shaking of semen should be avoided. Exposure of semen to sunlight should be avoided.
Different Tests to Assess the Sperm Quality
There are different test are available to assess the semen quality.
The classified under following headings:
- Macroscopic examination
- Microscopic examination
- Special biochemical tests
1. Macroscopic Examination
- Volume
- Colour
- Consistency/density
- Presence of foreign materials
- Gross motility
2. Microscopic Examination
- Mass activity
- Individual motility
- Concentration estimation
- Live and dead sperm estimation
- Abnormal sperm estimation
- Acrosome integrity evaluation
- Incubation test
- Cold shock resistance test
3. Special Biochemical Tests
- pH estimation
- Methylene blue reduction test
- Fructolytic index
- Oxygen uptake
- Pyruvate utilization test
- GOT activity
- Hyaluronidase activity
Even though various tests are available only few important tests are commonly followed as routine tests. Other tests are followed only during specific conditions.
