Paternity Efficiency in Turkey Differs Extensively After Heterospermic Insemination

Field testing the influence of sperm competition based on sperm mobility in breeder turkey toms

“…In similar paired insemination studies between low and high mobility tom turkeys, toms with high sperm mobility produced a majority of the offspring (62 to 100%). However, if toms within the same sperm mobility class were paired in the inseminate (high vs high or low vs low) relatively equal numbers of offspring were produced from each tom (Donoghue et al, 1999). Offspring ratios after pooling semen from 10 toms with equal number of sperm from each potential sire were consistent with paired competition trials, the high mobility males consistently outproduced average and low individuals (Donoghue et al, 1999).…”

“…An indirect estimate of the SST capacity has been achieved by counting the number of holes hydrolysed through the perivitelline layer of a freshly laid egg (Bramwell et al, 1995;Wishart, 1995). When semen from toms with high, average and low sperm mobility was pooled by group and used to inseminate hens, the mean number of holes observed for those toms with high and average sperm mobility was almost 4 times higher than those with low sperm mobility, indicating that sperm storage in the hen and the number of sperm at the site of fertilisation is reduced in toms with low mobile sperm (Donoghue et al, 1999). Sperm storage appears to benefit paternity outcome, because paired inseminations of equal numbers of sperm from cockerels (Birkhead et al, 1999) or toms (Donoghue et al, 1999) demonstrated that the majority of offspring were always sired by the male with the higher sperm mobility.…”

“…When semen from toms with high, average and low sperm mobility was pooled by group and used to inseminate hens, the mean number of holes observed for those toms with high and average sperm mobility was almost 4 times higher than those with low sperm mobility, indicating that sperm storage in the hen and the number of sperm at the site of fertilisation is reduced in toms with low mobile sperm (Donoghue et al, 1999). Sperm storage appears to benefit paternity outcome, because paired inseminations of equal numbers of sperm from cockerels (Birkhead et al, 1999) or toms (Donoghue et al, 1999) demonstrated that the majority of offspring were always sired by the male with the higher sperm mobility. Even when sperm numbers were shifted to favour the males with low sperm mobility by 3:1, the toms with high mobility still out-produced those toms with low mobility scores .…”

“…Similar findings were observed in evaluating highly selected broiler breeder males: sperm mobility was predictive of reproductive fitness even though fertility ranged from 3 to 100% . In early studies with controlled insemination doses and set laboratory conditions we have demonstrated repeatedly that sperm mobility influences fertility and paternity of offspring in turkeys (Donoghue et al, , 1999. These earlier studies screened larger flocks of toms (75 to 100 toms/flock) and then selected toms at either end of the mobility distribution to assess fertility.…”

“…While it is known that sperm competition exists, recent studies have demonstrated differences in paternity after pooling semen. DNA fingerprint analysis of turkey offspring produced from pooled inseminations revealed reproductive fitness was highly skewed among individual males (Donoghue et al, 1999). An individual tom produced more than 50% of 70 offspring in one trial in which semen from 10 toms was pooled.…”