What Does It Mean To Be Polled?
Polled is a simple "dominant" gene trait. One can get hornless heifers from your horned cows in a single generation. 50 percent of calves will be polled if the bull is heterozygous polled and 100 percent of calves if the bull is homozygous polled.
Why Use Polled Bulls?
Dehorning has become an animal rights issue in Europe, where laws now dictate who dehorns calves and how it is done. Specifically, by a veterinarian using anesthetics. Thus proactive EEC breeders have sought out the handful of herds with productive polled cattle and have placed their bulls into AI service.
Dehorning sets calf growth rates back two to four weeks, depending on how early it is done. For those who calve in the spring season, dehorning all calves at once can lead to a higher chance of infection from flies. Other blood-born diseases like Johnes, can also be transmitted unless you burn off the horn buds.
Do We Sacrifice "Genetic Value" To Obtain Polled Heads?
There are fewer polled than horned sire choices; at this point less than 2 percent of new Genomic tested sires entering AI in North America have polled heads. However, the existing polled sires are being widely used in higher profile cow lines to increase the number in the future.
Polled has higher frequency today in Red Holsteins than it does in Black & White, because Red breeders pay attention to the European genetics market and add in traits they can sell to them. Thus the polled gene is getting linked in pedigrees to the higher cow fertility and health trait profiles we see comparing Red Holsteins to Black Holsteins.
If polled were a "recessive" gene it would take an additional generation to acquire, which might feel like too great a wait to those chasing higher "index" sires. When it only takes one generation (as a "dominant" gene) your herd improvement scheme will not suffer. Polled sires may prove to be useful as "outcross" sources of heterosis vigor, helping you avoid "inbreeding" effects.
Are Markets Developing For "Polled" Breeding Cattle?
For the purebred breeder who would raise bulls to sell, there is a premium demand for polled sires. an example is Mark Yeazel, Ja-Bob Holsteins, Eaton Ohio. Besides the bulls he sells to European AI studs, he ships polled service sires as fas as Texas at a several hundred dollar premium over what anyone ever pays for a horned bull. Many good Michigan dairymen search for polled cleanup sires.
In the Jersey breed, we have more orders than we can fill for polled service sires. Virtually every USA AI stud has polled Jersey bulls in their program. The demand comes from graziers here in the USA and many subtropical parts of the world where the heat-resistant Jersey is the dominant dairy breed.
Our Sources for Polled Red & White Sires: