Four-Year Trial Confirms Plantain Cuts N Losses 33%
A four year trial has reaffirmed that mixing plantain into dairy pastures can help reduce nitrogen losses to freshwater while maintaining milk production and profitability, say researchers.
Too much of the high-sugar crop, too quickly, can lead to lactic acid in the cow's rumen, causing acidosis leading to rumen damage and even death.
Take it slowly, says DairyNZ, attend to detail and closely monitor animals during the transition.
Seed supplier Seed Force agrees, but says the ultimate goal ought to be a generous regime, the cows effectively getting as much beet as they want in a self-regulating intake.
Extension manager James White advocates a three-week transition to fodder beet with the aim of getting to "almost unrestricted" quantities.
"We're trying to get them to consume quite high quantities with the aim that once they're fully transitioned and the gut's adjusted and we hold them for another week, we can allow the animal to self-regulate – pretty much ad-lib feed."
White says by then the farmer would still be using moveable electric fencing to control the herd's access to the fodder beet crop but cows would hold back from breaking through, knowing they could have their fill.
"Imagine, if they're putting pressure on the line while being held at 8kg, and there's a breakout or the line goes down for any reason, they then [can] consume as much beet as they want and because they've been at 8kg their system hasn't adjusted to these high feeding levels.
"So even though the farmer thinks he's safe because he's done the transition well, he could still get acidosis in the middle of winter, if he's been restricted-feeding those animals.
White says that's why they advocate high-level beet feeding with limited supplements – because that's the safest form of beet feeding.
DairyNZ regional leader for Southland, Richard Kyte, says cows must be very slowly introduced to fodder beet by gradually decreasing pasture/silage allocation and increasing the crop over 14-21 days.
"[Pay] attention to every detail all the way through the transition process. We can see issues after the first eight to 10 days, when people think they are through."
Even for cows eating fodder beet during late lactation, careful transition up to their winter feed allocation is required, Kyte says.
"We've had cases recently of acidosis in cows, related to fodder beet. Acidosis can cause rumen damage or death and will definitely reduce a cow's food consumption.
"People [must be] vigilant: if they think cows aren't looking well, call a vet to check them out. The feed regime can then be adjusted to keep cows healthy."
White says many farmers will now have transitioned but should realise there was still danger of acidosis if they've been advised to keep their cows' beet intake restricted.
He says a high-beet diet should also be cheaper because of the relatively high cost of supplements such as hay, straw, silage or baleage.
A low-beet diet could be 8kg/day/cow with about 4kg/day/cow of supplements; a high-beet diet 10kg/day/cow plus 2kg of supplement.
"They're satisfied and they're self-regulating," says White. "They actually slow down the way they consume. They've got beet under their feet. They know it's not going anywhere. They're not having to pressure themselves."
