Friday, 16 February 2018 14:29

Cloud over fodder beet long-term

Written by  Nigel Malthus
DairyNZ is planning a national survey of fodder beet usage on farm. DairyNZ is planning a national survey of fodder beet usage on farm.

Farm veterinarians are struggling with the emerging health effects of long-term fodder beet use on dairy farms, says DairyNZ senior scientist Dawn Dalley.

The issue is now the focus of a big research grant from MPI’s Sustainable Farming Fund, at $565,000 the largest single grant in the latest round.

Problems are turning up on farms that have sorted out the initial transitioning issues, said Dalley.

“A lot of farms won’t have any problems for two or three or four years but what we’re seeing is that the farms that seem to be getting these issues, particularly over phosphorus, are the ones that have been in the fodder beet feeding game for up to 10 years now,” said Dalley.

Cows are showing very low blood phosphorus levels, despite supplementing with DCP or NCP, and giving low production despite good body condition scores. 

“On some of those farms the vets are struggling to understand what’s happening and animals aren’t responding to treatment that should be working. So we’re tying to look and see what it is on those farms that could be causing that.

“The challenge we’ve got in our grass-based system is that phosphorus has not been a mineral that we’ve really had to think about previously, because pastures have a pretty good calcium-to-phosphorus ratio; it’s something that’s new to our systems.”

The research will be a joint project by the South Island Dairy Development Centre (SIDDC), along with DairyNZ and AgResearch, and will partner with other agencies such as PGG Wrightson and Plant&Food.

Dalley said it will aim to better understand the mineral interactions at play when fodder beet is included in the diet.

The initial phase will include a national survey of farmers’ fodder beet usage.

“We know it’s being used differently in different regions. Farmers are very innovative and they’ve been trialling different things to make it work in their system – to really understand what the issues are that they’ve had, if they’ve changed anything with their feeding or mineral supplementation, and what that’s meant in animal health,” said Dalley.

Alongside that will be analysis of fodder beet’s mineral content, which is thought to differ between regions and cultivars. That aspect of the project will start on samples already held by Plant&Food and PGGW, which may have been analysed already for dry matter content but not minerals.

Because the SFF project funding starts in midwinter this year the project will be less hands-on in the first 12 months but then they will identify farmers to partner with, said Dalley -- those who’ve been using fodder beet for some time and are having issues, or those who’ve been feeding it without issues.

“In winter 2019 we will actually go in and take animal and feed measurements on those farms to fully understand their system, and try to tease out what’s happening at that mineral interaction level.”

Dalley said the project will also link with the Southern Dairy Hub, the new research and demonstration farm at Wallaceville, Southland, which is in the process of setting up four separate farm systems to run for three years, two using fodder beet and two using kale.

Dalley said some of the changes may be happening in calves even before birth so the Southern Dairy Hub project will be a good chance to track calves born to dams fed on kale versus those fed on fodder beet.

“We can take animals in two different directions and see what that means once they get into the herd.”

In its funding application to MPI, SIDDC called fodder beet “a game-changer in dairy systems” but said its benefits were jeopardised by animal health and welfare issues. If not addressed, those issues would cause a decline in fodder beet use, increasing cost, workload, and farmer stress, and could negatively impact the social licence to farm.

“What we want to do with this project is move away from the anecdotal information and put more science around what the opportunities are, where the challenges are, and how to rectify them, and give farmers real solutions based on science,” said SIDDC executive director Ron Pellow.

Fodder beet has gone from very little to about 75,000ha in 10 years. 

Pellow said that is the equivalent of 100,000ha of any other feed because of its high energy content. It is valuable in providing energy without too much protein, and so is useful in lowering nitrogen losses.

“It’s a really good feed and that’s why it’s taken off so rapidly, but we’ve probably got to do some things differently.”


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