In Part 1 of our crossbreeding series, we discussed the scientific basis behind the practice, and introduced the two concepts of complementarity and heterosis. In Part 2, we spoke about some of the practical considerations of crossbreeding, as well as a few pause-and-think concerns when choosing to go down this pathway. In today’s post, we’re looking at some brand new Dairy Australia-funded research which is examining crossbreeding – exciting news for those of us who are looking for real answers behind the practice.
Crossbreeding is often a topic that raises a great deal of passion amongst farmers and service providers. It seems like you’re either for it, or against it, with little in-between. But when I asked researcher Dr Jo Coombe (University of Melbourne) where she stands, it became clear that she strides the middle ground very well.
She used to work as a dairy vet for the old Timboon Vet Group (I’m sure some of my southwest readers will also recognise her rather marvellous British accent). Jo recognises that crossbreeding is a strategy that works well for some but may not for others. As a researcher, she’s passionate about the data that lies behind the practice and answering the ‘how’ of it all. She’s certainly not selling anything or pushing an agenda. Her aim is to help farmers back-up their decisions with numbers… and in this case, there are a lot of numbers to work through.
‘We’ve got this massive dataset from ADHIS which basically goes back 24 years or so,’ she tells me. ‘I mean it’s millions, millions of cows. We selected herds that had a minimum of 20% of the herd as non-purebred. That gave us 140,000 herd-years or lactations, and then we had to narrow that down to the breeds of interest.’
‘The breeds we’ve gone for are Ayrshire, Brown Swiss, Friesian Holstein, Guernsey, Jersey, Illawarra, Normande, Montbéliarde. If you have a first cross, three-way cross or back cross, that spreads it out to 329 different combinations. Obviously we’ve got to filter that, because if in a particular lactation there’s only one cow or two cows of that combination, then that won’t count.’ Still, that’s an enormous variety of breeds and crossbreeds to sort through.
Jo’s research is a combination of two data analysis efforts. The first requires trawling through pure numbers from the ADHIS databases, and the second is about talking with crossbreeding farmers about their current practices and records. I asked her if she’d found any trends so far as to why farmers are starting to crossbreed.
‘I have talked to at least half a dozen different farmers that are doing crossbreeding and from what I’ve talked to them about, the main motivation has been the problems with fertility and the longevity of cows within the herd, more than production reasons. The ones who seem to have consciously gone for it – I think mostly they’re chasing that longevity and improved fertility, and just trying to get a better calving pattern.’
Hmm, interesting. Digging deeper, there are three parts to Jo’s research.
‘The first is looking over the last 24 years and how many herds have crossbred. We want to see how those have changed in the last 24 years and also what kinds of breeds people use.
Study 2 will delve deeper and look at a subset of those crossbreeding herds and look at their fertility, longevity and production compared to purebreeding herds.
Study 3… I think this is most relevant to farmers. We’re going to compare first cross animals with back cross animals and three-way cross cows. Hopefully then that will really give us the answers as to what farmers should do after that first cross.’
I was curious about whether these answers would be definitive. Did Jo have any idea whether a two-way cross (or back cross) system or three-way cross system would come out on top as best? In typical researcher fashion, however, she was cautious about guessing without data to back her conclusion (a good habit to get into).
‘I can’t say whether a particular method is better at this stage. I’m thinking that farmers are still experimenting with that themselves. Trialling the whole back cross option, flipping between Friesian and Jersey for example, and occasionally they bring in the third breed… but they don’t know, some of them might be trying things out but they don’t have the numbers to back up whether it works. I’m hoping we’ll have the definitive answers on that – should they go back to the original breed, or should they go to a third breed?’
‘For myself and Michael [Pyman, another crossbreeding researcher], that’s our biggest goal – to be able to produce a guideline for farmers, backed up with science. We can’t be anecdotal.’
There are no current scientific guidelines about how to crossbreed under Australian conditions. Much information about it is pulled from other farmers’ experiences overseas – which, while very useful, may not hold true in Australian conditions or the systems of farming that are popular down here. As a result of this lack of information, a scattered mix of crossbreeding strategies are used across the country.
So, dear reader, this is where *you* come in. Jo currently has six Australian farms in her study that crossbreed – surely there are more of you out there? She’s aiming to have at least 20 farmers to talk to about crossbreeding under Australian conditions. However, she’s been restricted from approaching farmers due to privacy concerns and human research ethics.
So let’s lend a hand. Are you a farmer, or do you know a farmer, who fulfils the following requirements:
- Herd testing
- Has good records (especially sire data and fertility information – health would be a bonus)
- Willing to chat to Jo for 15 minutes? (I promise she’s terribly nice)
If you answered YES to all these questions, then send Jo an email at firstname.lastname@example.org or give her a call at 0425 712 832. She assures me she’d really love to talk to you, even if it’s simply just to get your ideas about crossbreeding or have a chat to her about the research. You don’t have to have an entire herd of ‘pure’ crossbreds – as long as it’s more than 20% of the herd, you’ll do.
In the meantime, did you have a particular strategy for crossbreeding? What works best for you on your farm? Leave a note in the comments below or email me at email@example.com.