Assessment of ejaculate quality and sperm characteristics in turkeys: sperm mobility phenotype is independent of time

Given a pool of genetically superior male turkeys, the subsequent selection of toms as semen donors for artificial insemination should be based upon criteria that are predictive of the tom's fertility and fecundity over the course of a production cycle. Recently, sperm mobility phenotype has been shown to correlate highly with fertility. Therefore, the objectives of this study were to determine: 1) whether sperm mobility phenotypes of individual toms were independent of time, and 2) the extent to which traditional semen quality variables changed as a function of time during the study interval. Sperm mobility phenotype was determined by objectively measuring the ability of sperm to penetrate 2% Accudenz solution at body temperature. During the initial assessments of a flock (n = 94), sperm mobility indexes (SMI) were significantly higher for the High Mobility Phenotype toms (56.61 +/-1.03% SMI) compared to the Low Mobility Phenotype (30.46+/-1.27% SMI, P < or = 0.0001) toms. Over the 5 mo of this study, the High Mobility Phenotype toms consistently had higher (P < or = 0.05) SMI values than the Low Mobility Phenotype toms, with SMI values similar to those of the initial screen. Ejaculate volume, concentration, and plasma membrane integrity showed no significant differences between phenotypes (P > or = 0.05). Sperm viability remained significantly lower (P < or = 0.05) over the course of this study for the High Mobility Phenotype toms than for the Low Mobility Phenotype toms. Because sperm mobility phenotype remained consistent through time, the Sperm Mobility Test provides a potentially important tool for selecting semen donors in turkeys.