The polled (non-horned) gene does not appear to be present in Fullblood Wagyu catlecattle but the polled gene exists in Grade and Purebred Wagyu cattle especially if they have been upgraded from an Angus base. Breeders of Purebred Wagyu cattle are likely to select for pallidness to avoid the need to dehorn their cattle. Depending on the method of dehorning the practice normally causes stress to the animal and weight loss for a period after dehorning. Bacterial infection is also reported to cause mortalities, particularly in northern pastoral regions.
The polled gene is the same gene in all breeds and is dominant. Therefore it is not important which base breed is used to introgress the polled gene into a breed. Homozygous (both copies of the poll gene are polled) polled sires are most desirable as they will always breed polled progeny.
If a breeder started with a Fullblood sire over base Angus females 100% of the F1 progeny would be polled and heterozygous ie one copy of the poll gene and one non-polled gene. In the grading up process using Fullblood sires 50% of the F2 progeny would be polled, 25% of the F3 progeny would be polled and 12.5% of the Purebred progeny would be polled .
Mating of a polled Purebred sire to a polled Purebred dam the probability of the progeny being homozygous polled would be 25%.
The scurred condition (small, loose, horny growths in the skin where horns would be) is controlled by a different gene to the polled gene and scuds are only expressed in polled cattle. The scur gene is sex linked and is dominant in males (animals with one copy have scurs) and recessive in females (scuds only expressed when the animal has two copies of the scur gene). Homozygous polled animals do not exhibit scurs so long term selection for pallidness will also eliminate scurs.
Wagyu breeders can now test their polled animals to check if they are homozygous polled. The test is available from the University of Queensland
Animal Genetics Laboratory (UQAGL) and the cost of the test is $27.50 (GST inclusive)
There is a proviso however. At this stage of development of the test for Wagyu about 28 percent of the samples submitted will not get a result. If
you do get a result for your animal it will be at least 90 percent accurate. eg the result given could be incorrect for up to 10 percent of animals.
The reason for the relatively high level of “no results” is that so far only 78 Wagyu animals have been tested at UQAGL using the test initially
developed for the Brahman breed. For breeds which have had much larger numbers of animals tested the level of no tests is as low as four percent.
If you are breeding for polledness in Wagyu animals then identification of a homozygous polled bull will be very valuable as it will produce 100 percent of polled progeny if mated to horned cows. A heterozygous polled bull will produce only 50percent of polled animals when mated to horned cows.
The test for homozygous polled animals should only be used on animals which are polled and both parents are polled.
The test is conducted on hair samples with hair roots intact taken from the switch of the tail.and sample submission forms and test kits can be obtained by calling UQAGL on 07 5460 1960 or email email@example.com
If you wish to discuss the use of the horn/poll test for Wagyu cattle please call the AWA Technical Officer, Carel Teseling.