Planning for fodder beet

That was one of several key messages to come out of a recent ‘Fodder Beet – Your Questions Answered’ field day in South Canterbury.

“Within a five tonne bracket is about as accurate as you can be if you’re talking about a large hectarage,” Lincoln University’s Jim Gibbs told the Beef + Lamb New Zealand event.

But that doesn’t mean to say yield shouldn’t be assessed, he stressed. Having a good estimate of yield is important for feed budgets and for preventing problems transitioning stock onto the crop.

To avoid biased selection of rows when checking yields, Gibbs’ fellow speaker, Seed Force agronomist David Walsh, flings a 4m rope with a weight attached into the crop, stretching the rope along the row nearest to wherever the weight lands.

“Otherwise people innately walk across the paddock to the heavier bits,” warned Gibbs. “Gravity draws them to them.”

Another way to do it is to use a spreadsheet’s random number generator to provide coordinates for sample points in a paddock.

Whatever the location method, having weighed roots and tops from 4m row samples, some plants, preferably whole, should be sent for dry matter assessment rather than relying on typical cultivar dry matter figures. Gibbs pointed out he’s seen Brigadier samples from 6% dry matter to 19%, and warned against DIY assessments. “If it’s important to you, get someone to do it professionally.”

If beets have to be sub-sampled, quarter them crown to tip rather than slice across, but whole bulb assessments are much better.

Having estimated yield, transition cattle onto the crop feeding 1-2kgDM/head/day initially and increasing that 1kg every second day. Lifting beet by bucket to feed on grass could be useful initially, as could “transition headlands” of grass.

Allocation during transitioning should be on area and hence quantity, using the upper limit of yield estimates. Gibbs warns against allocating by grazing time because some animals will wolf down a lot more than others. “It’s extremely dangerous to do it on time, especially with dairy cows.”

Once one mob is transitioned it could be used to open up other paddocks to facilitate transitioning other mobs.

Gibbs warned cattle will start eating all the beet they can, typically 8-9kgDM/head/day for R2 beef steers, after a week on the crop but the rumen takes a fortnight to adapt, so if problems do occur it’s usually in this later stage of transitioning.

But Gibbs stresses there is “nothing dangerous about feeding fodder beet if you follow the rules” and in some ways it’s simpler than other winter feeds. “You’ve not got to worry about nitrate or bloat too like you do with brassica.”

Once transitioned, unrestricted feeding is safest so cattle are always eating all they can. If restricting intake due to feed shortage, or rationing to dairy cows, hot-wires have to be secure. “A lot of people don’t have the electricity they should have. It should be glowing in the dark.”

For beef cattle over 350kg on unrestricted beet the only supplement needed is 1kg/head/day of a fibre source. “Pick that on price.”

Below that weight, beet will likely not provide enough protein so a green supplement such as grass or lucerne silage should be used, particularly for 180-250kg cattle.

Grazing on/off grass or possibly a greenfeed such as ryecorn – taking care that it remains green and hasn’t been browned off by frost – is an alternative.

“If you’ve got really good quality grass hay… you can get away with it too,” he added, in response to a question.

Supplementing with PKE would replace beet, likely increasing the cost of the diet, but a positive is PKE’s fat content could drive intake and high phosphate content could help compensate where beet’s content is too low for sensitive cattle such as late pregnancy dairy cows.