Studies on Dimensional Characteristics of Spermatozoa in Pure and Strain Crosses of White Leghorn Cockerels

Abstract

Sperm head dimensional characteristics were evaluated in three pure strains (M, N, and P) and three strain crosses (N × P, M × N, and P × M) of White Leghorn cockerels. A total of 120 collections from 24 cockerels were taken. The average sperm head length recorded was 14.58 ± .09 μ, with an average maximum value of 15.29 ± .19 μ for spermatozoa from the P × M strain cockerels. The average sperm breadth was found to be .722 ± .005 μ. Maximum values were found for spermatozoa from the M × N strain cockerels that averaged .735 ± .004 μ. There was a significant difference (P<.01) between strains for sperm head length. The P × M strain had a significantly longer sperm head length than the other strains. This may be associated with heterosis. There were no significant differences among strains for sperm head breadth.The mean sperm head area was recorded to be 10.61 ± .08 μ2. Maximum sperm head area was observed in semen from P × M strain cockerels (11.03 ± .15 μ2). The average sperm head shape was found to be 20.14 ± .22. There were significant differences (P<.01) among strains for sperm head area and sperm head shape.The repeatability estimates for all the dimensional characteristics showed that they are highly repeatable traits, indicating that additive gene action is playing an important role in the expression of these traits.