Crossbreeding

Why crossbreed? 

Are you struggling with poor fertility and health in your dairy herd? Would you like to improve lifetime production and, at the same time, have fewer problems with your cows? Crossbreeding can offer a solution to these issues. 
 
Are you experiencing some of these problems in your herd?
 
  •  Low fertility
  • No increase in lifetime production
  • High veterinarian costs
  • Too much work per cow
  • Too many problem-cows
 
When switching from a pure-bred herd to crossbreeding, you don’t need to worry about the production level dropping. With the right combination of breeds in your crossbreeding strategy you can achieve improvements in lifetime production and, at the same time, reduce the costs and amount of work per cow.

One of the great benefits of crossbreeding is heterosis. Heterosis is the increase of favorable characteristics of a hybrid organism over those characteristics of its parents, when two unrelated breeds are crossed. Research has found that heterosis has the greatest improvement in traits like Vitality, Fertility, Health and Survival. Crossbred cows stay longer in the herd and lifetime production is increased.  

Heterosis

Heterosis is created when two unrelated breeds with different genetic heritage are crossed together. The lower the relation between the breeds, the greater the degree of heterosis achieved. 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 (e.g. VikingHolstein and VikingRed); 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


With pure bred cows you need to keep an eye on the level of inbreeding in your animals. Inbreeding depression negatively impacts traits connected with survival and overall fitness, e.g. reproductive rate, health and disease resistance. It therefore increases the risk of recessive lethal diseases and defects, reduces the performance of your cows and also reduces adaptability to production environments.
 
Inbreeding leads to the following most common situations

  • Cow's performance does not match the breeding values
  • Problems with fertility
  • Problems with calving and more stillborns
  • Cows lose vitality
  • More labor for the farmer
  • Lower cull value of cows
  • Lifetime production does not improve
 
The opposite of inbreeding depression is hybrid vigor (heterosis) where we have animals whose parents are not related at all. This increases fertility, health and even production.  
 
The main point in crossbreeding is to get all the good traits and lose the bad, undesirable ones!  

Two-way or three-way rotation?

Two-way 


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 F1. Heterosis rises again in the F3 generation, but then levels to 67% in a few generations. 
 
Here you can see an example of a Holstein and VikingRed cross and the development of heterosis level in different generations. 

Three-way 


The three-breed crossing can be seen as the optimal crossbreeding system as heterosis remains higher than in two-way crossbreeding. With four-way crossbreeding even higher heterosis can be achieved, but maintaining the correct rotation becomes more complicated and it's harder to find breeds that complement each other well and are from unrelated populations. Four-way crossbreeding is therefore 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 with 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 the F3 generation. After a few generations, the heterosis level steadies at 86%
 
We will keep the desired traits in dairy production, but as an added benefit the crossbred offspring will have improved fertility and health traits.