Dunedin company AbacusBio has been working on the research project with DairyNZ for more than a year and in mid-August presented its first findings at the 10th World Congress of Genetics Applied to Livestock Production in Vancouver.
NZ Animal Evaluation Limited (NZAEL) manager Jeremy Bryant of DairyNZ, which funded the work, said the investigations were the result of industry interest in the area but were still in the early stages.
“It is still very much a work in progress but what we may get out of it in the end is a different ranking for animals catering to DairyNZ system four and five farms. These farms feed in excess of one tonne of dry matter per cow as imported supplement but still rely heavily on grazed pasture. They represent about 20% of farms in New Zealand,” Bryant said.
AbacusBio scientist Peter Amer said the thinking was the new ranking would likely weight milk, fat, and protein production higher than currently in Breeding Worth and, if the next phase of research confirmed it, some of the traits other than production (TOPs) such as udder overall and udder support.
‘There is a lot of research and onfarm evidence to show that Breeding Worth works well across a wide range of systems including high input.’
“Anecdotally, cows which are managed to achieve high production can be more prone to udder breakdown and culled because of it. We are keen to test if this shows through in the national data we have,” Amer said.
Somatic cells may also need to be more heavily weighted as the more a cow produces, the more milk and revenue is lost when it gets mastitis or if it contributes to pushing the herd over bulk tank SCC thresholds.
“However, fertility becomes slightly less important on high-input farms as in low-input systems cows tend to be dried off on one date but, in high input farms, cows which calve late are usually able to be milked late into the season.”
Amer said one of the reasons for the research was the high quantity of North American genetics now in the New Zealand dairy herd.
“In the past 10 years the amount of US genes in our black and white cows has risen to about 40% to 50%. The New Zealand genetics companies have done a very good job blending these with our own genetics and making sure through sire proving that these genetics work on our farms and are better than what we had.
“Interestingly, looking at overseas and New Zealand bull rankings there is very little difference between the same bull in the Netherlands and in the US but there is a big difference if you rank that same bull here.”
He said the push for the research had not only come from high-input farms but also from grass-based systems which had low stocking rates.
“These people are asking us the same questions so it’s not about high-input or feeding buckets of barley. It’s really about high production per cow herds.”
The cows that stood out with the new weightings were Friesian.
“Jerseys tend not to respond as well as other breed types in high-input systems but that doesn’t mean we should look differently at them. Jersey and crossbred cows are an incredible asset for our wide range of farming systems which other countries don’t have.”
Amer said the next step was to use industry data to see how bulls re-ranked for individual traits in different production environments. So far the work had focused on adapting economic index weightings to determine if different priorities should be placed on traits for the higher output systems.
“If we go ahead we can find the high production per cow farms in the data and see how the bulls’ daughters are doing on them compared with on low production per cow farms.”
However, there was still a lot of work to do before launching a secondary economic index, Bryant said.
“There is a lot of research and onfarm evidence to show that Breeding Worth works well across a wide range of systems including high input.
“We will have to make sure that having two economic indices is justified and won’t confuse farmers as this could then slow down the rate of the national herd’s genetic progress.”
Peter Amer is leading the AbacusBio team of Bruno Santos, Tim Byrne, and Bram Visser.
“When Bruno gave the address at the world congress in Vancouver there would have been 400 or 500 people in the audience so it shows there is international interest in what we are doing here,” Amer said.
