title: Eight generations of selection for duration of fertility of frozen-thawed semen in the chicken.
abstract: The response to eight generations of selection for duration of fertility of frozen-thawed chicken semen, the correlated responses of other fertility parameters of frozen-thawed semen and the fertility of fresh semen, and the heritabilities of frozen-thawed and fresh semen were studied. The selected and control lines were derived from a base meat-type control male population developed at Peel's Poultry Farm Ltd., Port Perry, Ontario. Selection has improved duration of fertility of frozen-thawed semen significantly (P less than .01) with the mean increasing from 1 day in Generation 1 to 5 days in Generation 8 and an average improvement per generation of .29 day since Generation 3. There were significant (P less than .01) correlated increases in percent fertility for 2 to 8 days postinsemination and percent fertility for the duration of fertility of frozen-thawed semen as well as the fertility of fresh semen. Percent hatchability of fertile eggs of frozen-thawed semen did not change. In Generation 8, means and standard errors of fertility parameters of frozen-thawed semen in the selected and control lines, respectively, were: 38.54 +/- 1.39 and 25.58 +/- 1.77 for percent fertility for 2 to 8 days postinsemination, 47.73 +/- 3.54 and 32.02 +/- 2.17 for percent fertility for the duration of fertility, and 78.21 +/- 1.56 and 79.27 +/- 2.53 for percent hatchability of fertile eggs. For fertility of fresh semen, means and standard errors were: 12.69 +/- .20 and 11.54 +/- .42 for duration of fertility, 82.91 +/- 1.45 and 75.71 +/- 2.83 for percent fertility for 2 to 8 days postinsemination, and 71.89 +/- 1.25 and 69.22 +/- 2.06 for percent fertility for the duration of fertility. The means of the heritability estimates of the fertility of frozen-thawed and fresh semen, respectively, ranged from .01 to .31 and -.01 to .21. The realized heritability of duration of fertility of frozen-thawed semen, based on five generations, was .17 +/- .05. The phenotypic correlations of duration of fertility of frozen-thawed semen with percent fertility for 2 to 8 days postinsemination and percent fertility for the duration of fertility of frozen-thawed semen were high and positive and correlations between fertility of frozen-thawed and fresh semen were low but positive.
mesh_terms: D000818:Animals; D002645:Chickens / Q000235:genetics* / Q000502:physiology; D005298:Fertility; D008297:Male; D012641:Selection, Genetic; D012661:Semen / Q000502:physiology*; D012662:Semen Preservation / Q000662:veterinary*