Crossing breeds the first time can be daunting!

24
Mar
2017
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Designing cattle by combining the genetics of different breeds has enabled livestock producers to better match their cattle to their environment and market for a long time.

The large poultry and pig companies mostly produce designer animals. Straight-bred animals in these industries play only a minor part.

Combining two or more breeds produces an animal with a genetic package average of the breeds involved.

The breed effects of the components are the main reason for doing so – a bit of extra growth from one breed, extra muscle from another, earlier maturing from another.

Charolais bull angus cow web

It’s a skill to pick and combine the breeds in the best percentage for the beef operation at hand.

Combining breed effects is the main reason for crossbreeding, but the extra advantage from heterosis is the other.

Heterosis delivers hybrid vigour, as the crossbred animals recover from a level of inbreeding most straight-breds probably have.

The extra production is described as production greater than the average of the parents for the trait in question. It doesn’t mean the crossbred will outperform both parents for a particular trait.

Dairy farmers still milk Friesians in large numbers, because the Friesian crossbred still produces less milk than the straight-bred.

In the cattle industry in southern Australia, most producers have grown up with a straight-bred herd. Up until the early 1970’s this was almost entirely British breeds.

Market forces today would suggest that some straight-bred herds return more money per kilogram of beef sold. This of course needs to be balanced with the possible extra kilograms of beef a crossbred herd should produce.

People trying new things go gently until their confidence increases.

Confidence can increase exponentially once a few wins are scored.

Crossbreeding production for someone with a long straight-breeding history can be daunting.

The easiest way to start is to use a different bull over some of the cows that are older, and are not needed to breed replacements to go back into the herd.

It’s a ‘try it and see it’ approach. If it’s not what the producer wants they can easily go back to straight-breeding.

In some recent modelling I ran for the Tumbarumba Beef Group, we looked at the age and number of females that are required to breed replacement heifers for the herd.

This is called the ‘replacement rate’, and the age structure of the herd, particularly the age at which older females are sold, has a big effect.

In a younger herd, more heifer calves are needed to be grown out as replacements.

In the herd we designed, the replacement rate increased from fifteen percent to twenty percent as the oldest cow kept went from ten to seven years.

In the young herd, there was a higher number of replacements needed, but also a higher number of animals within each age group.

Both herds showed that once a cow had gone through her third pregnancy, her calves were no longer needed as replacements.

This meant that all cows from then on, regardless of the eventual age they are culled, can be crossed to another breed, and all these higher producing crossbred progeny can be sold.

A lot of cattle producers don’t crossbred, and the reasons are fair and many.

However using a second breed over the older cows is one way to start.

Once the success of this has been thoroughly enjoyed the process becomes intoxicating!

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