VGO 511: Veterinary Andrology and Reproductive Techniques (1+1)

HYDROGEN ION CONCENTRATION OR pH OF THE SEMEN

• The pH of the domestic animals at the time of collection is having practical value in accepting or rejecting a semen sample.
• Depending upon the concentration and activity of the spermatozoa the pH of the semen varies.
• Since the sperm concentration and activity can be measured directly there is no better information gained with pH.
• The pH of the semen can best be measured with pH meter. It can be measured with pH paper or by using dyes also.
• The use of narrow range indicators is more convenient in the routine work of artificial insemination.

pH paper

• It is more convenient for routine work.
• Tear the paper strip from the indicator book (touch the paper only at one end).
• Tip the torn end of the paper in a drop of semen.
• Look for the first change in color.
• Find the matching color on the cover book and note the corresponding pH.

TOP

Indicator dyes (Bromothymol blue or Bromo cresole purple or Phenol red)

• Take two capillary tubes which are marked for equal volume
• Take the semen in on capillary and dye in the other capillary up to the marked volume.
• Add the semen and dye in a watch glass and mix it well.
• Take the mixed solution in a clean capillary tube and the color is compared with the comparator set (which has set of capillary tube according to the pH).
• pH of the semen is assessed by reading the matching capillary from the comparator set.
• The ranges of pH that can be assessed by using different dyes are as follows.
  • Bromothymol blue - 5.2-6.8
  • Bromo cresole purple – 6.0-7.6
  • Phenol red – 6.8 – 8.4.

TOP

pH of semen of different species

Species	pH
Bull	6.8
Stallion	7.4
Ram/Buck	6.8
Boar	6.8
Dog	6.7
Cat	7.4

• pH of the semen affected during
  • Inflammatory conditions affecting the accessory sex glands
  • When bulls are used excessively – Alkaline pH
  • Incomplete ejaculation – Alkaline pH

TOP