Williams G
Milk Marketing Board Cattle Breeding Centre, Welshpool, Powys.
Vet Rec. 1987 Sep 12;121(11):248-50. doi: 10.1136/vr.121.11.248.
A specific spermatozoal defect was found in two apparently sterile Charolais bulls. Eighty to 90 per cent of the spermatozoa had a stump, or a droplet-like appendage, instead of a normal tail.