The reliability and efficiency of various methods for estimating spermatozoa concentration.

A study was conducted of the reliability and the efficiency of four methods to estimate concentration of spermatozoa in chicken semen. The methods used were hemocytometer, Coulter counter, optical density, and spermatocrit. Twenty-four samples of pooled semen (5 males per sample) were used in this experiment. Sperm concentration estimates were determined on each of three subsamples: pure semen, semen diluted 1:1, and semen diluted 1:3. The average time to prepare and evaluate 6 replications of each subsample with the hemocytometer, Coulter counter, optical density, and spermatocrit methods was 9.0, 2.6, 2.3, and 4.4 min, respectively. Correlation coefficients ranged from .78 to .93 between the hemocytometer and either optical density or Coulter counter in both pure and diluted 1:1 and 1:3 samples. However, no significant correlation was observed between the hemocytometer and spermatocrit in the 1:3 dilution. The reliability expressed as coefficient of variation for each technique was: hemocytometer 17.9%, Coulter counter 1.57%, optical density 2.24%, and spermatocrit 9.95%. It is concluded from these results that the optical density and Coulter counter methods are more reliable and more efficient (less time consuming) than either hemocytometer or spermatocrit methods in estimating semen concentrations in chickens.