Pasture skills power production

Moving south from Waikato in 2008, the couple are in their second season sharemilking 900 crossbred cows for John, Yvonne and Richard Evans at Springhills, central Southland.

In 2009/10 their predecessor on the farm achieved 268,000 kgMS from 800 cows. The Roskam’s pumped that up to 320,090 kgMS from 880 crossbreds in 2010/11, and this season are on target for about 385,000 kg/MS from a herd of 910.

About 170 Southland farmers gained an insight into the management behind that at the awards’ winner’s field day on the 296ha property a fortnight ago.

The couple, who won the Ravensdown pasture management award as well as the overall title, say pasture quality has a major impact on milksolids production, and their system balances pasture and cow demands to maximise sustainable profit. 

Farm walks are a crucial part of their strategy to ensure targets are met, with these happening weekly from August to May and monthly in June and July.

“We try to target a 1500 kg/DM residual all year round and use our pre-grazing calculations to achieve that,” says Billy. Pre-grazing cover is calculated by multiplying the stocking rate by intake and round length, plus the optimum residual, while feed cover is distributed over the farm in a wedge.

“We just focus on the basics,” Sharn adds. “We just work out the calculations and go from there.”

On average their cows were 490kg as at December 1. They have to walk 4km/day on average and by last month’s field day were still producing 1.4kg/MS.

“We calculated the maintenance, the walking, the milksolids and the liveweight gain, which works out that they need 191ME (megajoules of metabolisable energy). Divide that by an 11 ME feed, and it works out that we need 17.4kg per cow of feed offered.”

Good stockmanship is also crucial.

“You can plate a paddock, and use scales and dry matter tests – but at the end of the day you’ve just got to look at the cows and see whether they’ve been fed enough.”

Average pasture cover targets throughout the season are: 1800kgDM/ha at June 1; 2100kgDM/ha at August 1; 2050-2100kgDM/ha in summer and 2300kgDM/ha down to 1800kgDM/ha in autumn, to maximise pasture growth rates.

“This year we started at 1800kgDM/ha and built the cover up, then the snow hit, followed by the drought, and we got extremely high growth out of that and cut a lot of baleage.”

The first round finishes no earlier than September 20, followed by a 20-25 day round to the end of February, then a 30-35 day round through March and April, and 40 days in April and May.

“We’re putting in more silage now and building up our covers while it’s dry and then when it gets wet we’ll let the cows have a bit more area.”

Feed wedges, average pasture cover and round length are used to calculate supplement use and to top up the cow’s diet.

A wagon with scales and dry matter testing of supplements ensure they know exactly what’s going to the cows.

“Any genuine surplus is put into baleage first.”

Effluent is spread by slurry wagon to improve fertility in selected paddocks – “not a cheap exercise, but we try to use it to target certain areas on the farm” – and pods.