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Archive:Think Carefully About Crossbreeding

Published 5 May 09

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Crossbreeding is a hot topic among farmers, seen as a solution to some of the health and welfare issues that have to be tackled on a regular basis, such as fertility and mastitis. But farmers considering crossbreeding need to think very carefully about the choices they make, and look at all the alternative options available before deciding if it is really the right approach.

There is no quick fix to any breeding issue, and crossbreeding is not for everyone. It's important that anyone considering crossbreeding realises that if it isn't done well it is highly likely to complicate and exacerbate problems instead of solving them.  It can also be a slower way of making herd improvements - the genetic information available for assisting crossbreeding decisions is simply nowhere near as comprehensive and reliable as that which we have for within breed improvements. The recommended approach in the first instance is to look at the current within breed tools that are available to tackle particular breeding issues, as the vast majority of problems can be addressed with the tools available, negating the need for crossbreeding. 

There is an extensive set of tools to satisfy within breed requirements for genetic traits.  These include the Profitable Lifetime Index, (£PLI) which includes direct measures of milk, fat, protein, lifespan, fertility, and predictors for reducing lameness and mastitis - through locomotion and Somatic Cell Counts. DairyCo is currently part funding, with other industry partners and Defra, 'Expanding indices', a research project which has just completed its first year. This will expand the current portfolio of indices available with two new additional indices, one for calving ease and the second for direct udder health. In addition the project will aim to improve on the current Lifespan index.

With these indices, breeders will be able to broaden their selection policy, reducing the cost of poor calving ease and improving further on udder health issues and increased longevity. For some time the £PLI has ranked traits according to economic value, and up until 2007 Production traits were given higher weightings than health and welfare. However, last year, the ratio was revised, and is now tilted in favour of 'Fitness' traits, with a ratio of 55:45 non-production to production.

This goes some way to demonstrating that in the past we have increased production at the expense of health and welfare, but that we're now making sure that in the future we continue to increase production (albeit at a much slower rate) and health, without compromising the animals' 'Fitness'.

For the future, DairyCo breeding+ is now working on a tool that will enable farmers to adjust the relative weights of the traits under selection for themselves.  So if they want to select a bull with particularly good daughter fertility, then that can be given a higher level of importance than, for example, fat yield.

According to Dr Mike Coffey of SAC, crossbreeding is something that only those who are already making good and successful within breed decisions should really be considering. "Moving into crossbreeding means keeping extensive records on the sire of each cow. It also requires farmers to keep a large inventory of semen as they have to have the right breed to hand at the point the cow is bulling.

"If farmers are prepared to invest the time and effort then there are rewards to be had, but it's important that we also concentrate on improving the breed we have now because without pure breeds there can be no crossbreeding." DairyCo extension officer Andy Dodd agrees. "Farmers need to be sure of what they want to achieve when making breeding decisions. Whatever bulls are eventually used, it's vital that you use genetic data and only select top bulls that suit your needs, it is also important that you are realistic about the results.

"Many farmers seem to make the choice to cross breed to improve their herd performance, but there is little information out there to guide them and also a lack of information regarding sires and their breeding potential, unlike selection within breeds.

"Crossbreeding can be beneficial in helping to combine breed qualities such as yield, fertility and milk components," adds Mr Dodd.  "When it is done well farmers can benefit from heterosis, or hybrid vigour, where the crossing of two breeds results in extra, additional benefits for that trait." 

With crossbreeding farmers need to consider a number of potential problems, such as loss of pedigree status, TB valuations and surplus stock sales. While there are many published results showing the benefits of crossbreeding in a variety of species, at present there is a very limited amount of scientific evidence from UK farms to support any crossbreeding decision. To that extent DairyCo breeding+ is now developing the genetic data, based on UK recorded data collected from milk recording organisations, that will make relative genetic comparison of bulls between breeds, as well as within breed, possible.

Overall, the most important factor is that all decisions made about breeding are well informed, whether for crossbreeding or within breeds. It may only take a minute to breed a cow, but it can take a lifetime to breed out the problems created by a poor breeding decision.