There is an increasing interest in using polled bulls, to breed away from horned cows and thereby avoid dehorning of calves. In other countries such as Germany, this is an area that is greatly in focus, and they have many polled bulls to choose between. In the Nordic countries, the focus has been limited until recently. Currently, approximately 10 % of the AI bulls carry polled genes, but this number is increasing.
6 Jun 2019 - By Ruth Bønløkke Davis and Anders Fogh, SEGES
Polled bulls are gaining popularity
Use the best polled bulls
The actual costs associated with dehorning a calf (including labour) is approximately €7, which corresponds to the value of 1 NTM-unit. In this calculation, any effects following the dehorning are not accounted for. If this matter is regarded purely economically, the benefit of choosing a polled sire, does not outweigh the benefit of using a bull with a high NTM value. However, if there is a polled bull at the same genetic level, then there is an added benefit of using this bull.
There can also be other reasons to use polled bulls besides saving money. There could be ethical considerations or a wish to save time and avoid a somewhat tedious task. Whatever the reason for choosing a polled sire, it is important to understand the consequences.
Be strategic when using polled bulls
Choose polled bulls with a high NTM and use them strategically to get the maximum amount of calves without horns. The polled gene is inherited dominantly, which means if the animal carries the gene, it will not have horns. This makes it relatively easy to obtain a high number of polled animals in the herd. By using a heterozygously polled bull, on a horned cow, 50 % of the calves will be polled. If a homozygous bull is used all the calves will be polled. VikingGenetics displays the polledness in the names of the bulls e.g. VH Monty P is heterozygote polled and VR Henrik PP is homozygote polled.
If the best polled bulls continuously are used on horned cows, the proportion of polled animals in the herds will increase, without compromising the genetic level. If a cow is heterozygous polled, 50 % of her calves will be polled, so there is no need to use a polled sire as well.
High genetic level of many polled bulls
Fortunately there are many polled AI bulls, especially for VikingRed and VikingHolstein. Most of these bulls are heterozygote polled and they are at the same genetic level as the best AI bulls on the market. Homozygous polled bulls are on average at a somewhat lower genetic level and are often closely related.
Take home message: Use polled bulls but do it strategically and don’t compromise on the genetic level!