Enjoy the free benefits of heterosis 

Heterosis gives you natural resistance against the effects of inbreeding. Your herd will remain healthy and long-producing. By using a three-way cross you can achieve steady heterosis of 86% in your herd. This way the genetic heritage of your herd remains stronger.

What is heterosis? 

Heterosis is created when two unrelated breeds with different genetic heritage are crossed together. The lower the relation between breeds, the higher the heterosis that you get. The effects of heterosis are the opposite of inbreeding depression which is a decline in performance of dairy cattle. Research indicates that heterosis can really improve traits like Vitality, Fertility, Health and Survival. There is also an indication that heterosis can increase production compared to the parent average. Heterosis is the extra added genetic value that is generated above the parent average.

When we have breeds that share the same breeding goals, we can get improved results from crossbreeding. As an example, we have two dairy breeds and we cross them together (eg. VikingHolstein and VikingJersey), we will keep the desired traits in dairy production but as an added benefit the crossbred offspring will have improved fertility and health traits. 

Counteracting inbreeding

Pure breed populations face the threat of inbreeding depression because animals are starting to become more closely related to each other. Inbreeding depression is a big threat in purebred populations because it effects negatively on traits connected with survival and overall fitness, e.g. reproductive rate, health and disease resistance. Hence, it increases the risk of recessive lethal diseases and defects, reduces the performance of your cows and also reduces the adaptability to production environments.

The opposite of inbreeding depression is hybrid vigour (heterosis) where we have animals whose parents are not related at all. This increases fertility, health and even production because this crossbred animal doesn't get the possible negative traits in one breed population (eg. possible hoof health issues typical for Holstein). 

The main point in crossbreeding is to get all the good traits and lose the bad undesired ones!  

Two-way or three-way rotation?

The simplest model of rotational crossbreeding is the two-way cross where two different breeds are crossed. The next generation is called F1 and if the offspring from this cross is mated back to one of the original breeds, this is called a backcross. The highest level of heterosis is always in the first generation and the level decreases in following generations. When F1 cows are backcrossed, in generation F2 the heterosis is halved compared to the level in the F1. The heterosis rises again in the F3 generation but then levels to 67% in few generations. Below you can see an example of a Holstein and Jersey cross and the development of heterosis level in different generations. 

Two-way cross 

The three-breed crossing can be seen as the optimal crossbreeding system as the heterosis stays higher than in two-way crossbreeding. With four-way crossbreeding even higher heterosis can be achieved but maintaining the correct rotation gets more complicated and it's harder to find breeds that complement each other well and are unrelated populations. Therefore, the four-way crossbreeding is not recommended. In three-way crossbreeding the first generation is also called F1, but instead of starting the backcrossing with the cows, the cows are mated to a third breed. The heterosis stays at 100% for the first two generations, but then drops when the first backcrossing is made to one of the original breeds in F3 generation. After few generations the heterosis level steadies at 86%. Below you can see an example of a GoldenCross cross and the development of heterosis level in different generations. 

Three-way cross