Winter hunger busters

01-09-2010 | Joanna Grigg

Got feed? They have.

Two Marlborough hill farms, Meadowbank and Jedburgh, had good winter crops on display when visited by farmers on the Beef + Lamb New Zealand Monitor Farm day.

Fifty farmers saw first-hand how brassica, annual ryegrass and Omaka barley are used to feed ewes and cattle through winter, freeing up hill country to grow feed for lambing. While winter cropping systems are not new, there were plenty of fresh ideas on making them successful.

The key message was that summer fallow, ground preparation and timely sowing are critical to a profitable crop.

William and Duncan Grigg spend time planning which blocks at Meadowbank will go into crop. The long-term aim is for winter cropping to be used as a stepping stone towards establishing 170 hectare (ha) of lucerne and 250ha of quality permanent pasture. The balance (2400ha) is oversown top-dressed extensive hill country.

This year 40ha of crop was grown, half for multiple-bearing ewes and the rest for yearling and trading cattle.

William said key to success is early spring spraying of pasture, even though late grazing is tempting. He targets late October although he is guided by whether moisture is still in the soil.

"Effectively you are transferring spring moisture through to autumn."

Grazing off the dead matter is vital to a good spray kill, he says. Omaka barley or a rape/Italian ryegrass mix are drilled in mid-February. The barley is sown deeper as the seeds are bigger, meaning it can strike without rain. "It really takes off when the rains do arrive."

Barley is usually ready for first grazing by mid-autumn. The rape/Italian ryegrass crop is later, grazed from late June. The crops give 40 days of feed for ewes leading up to lambing on August 12th.

"We usually sow a lot more rape than we need for ewes and this is used to winter trading cattle."

William was a bit disappointed with this year's yield of 8.4 tonnes/ha (t/ha) compared with the almost perfect crop last year. The whopper Goliath crop yielded an impressive 16t/ha at the end of June. The poor season is graphically illustrated by the fact that it took 23ha to feed ewes this winter while it took only 10ha last year. Titon rape was used this year.

In the cracker 2009 season Meadowbank wintered 474 two-year trading cattle, while this year only 80 were bought. Despite this, William looks on the bright side.

"The beauty of the whole system is when you do get a dry autumn you still get an acceptable crop if you summer fallow."

A crop yielding 12t/ha produces feed one-third cheaper than an 8t crop. William calculates that an 8t crop cost him 6.2 cents/kg DM to grow while his 16t crop cost only 2.8 cents/kg DM (see Table E). This is at an establishment cost of $500/ha (two sprays).

To put this in perspective, they are both far cheaper than feeding supplements. Even developing the "native" hill pasture (costing $789/ha because it includes four tonne of lime and higher glyphosate rates) and yielding eight tonnes gave a feed cost of only 9.9 cents.

William has seen the risk from relying on pasture.

"I will never forget the horrible year of 2001 when the farm had no winter feed sown and we had to buy in feed.

"It cost us a fortune and we won't do that again."

William did not include spring regrowth in his calculations. He treats it as a bonus. If pugging is minimal the ryegrass, in particular, should yield well.

"That is why it is included in the brassica mix."

Chris Dawkins, from previous Monitor Farm The Pyramid, commented that including ryegrass reduces pugging.

When it comes to grazing, Duncan Grigg checks nitrate levels frequently, as part of his crop management. When wet and cold, ewes are allocated 1.8 to 2kg DM/head. If dry, rations are trimmed to 1.5kg. A 1/8th quadrant is thrown over four crop samples and cut, dried and weighed. From this the dry matter can be worked out. More cuts can then be taken using the fresh weight to estimate dry matter.

"It doesn't go down too well in the home camp when the oven is full of rape for two days," William says.

Brassica is assumed to have an energy value of 12.3.

Ewes are given a pasture run-off at all times and, if really wet, are run on to the crop for a few hours, then shut off it. 

"Otherwise the bad-mannered ewes break out towards the end of the day."

Iodine is provided via an oral potassium iodide at scanning and again pre-lamb via Vet Centre LSD.

Winter crops allows the Griggs to shut up most multiple lambing blocks two months before lambing. Cattle are sometimes used to tidy up the lambing blocks if covers are too high. Over winter the singles run through a couple of their lambing blocks, then clean up laneways and a small lease block before set stocking. 

The night before the tour 2000 ewes had broken into the demonstration block and "hammered" part of it, but William estimates it had covers of 1500kg DM, despite a slow growing season. The block had been sown with 20kg of Flecha MaxP tall fescue, 5kg of Prairie grass, 6kg of Woogenellup subterranean clover and 6kg of Arrotas arrowleaf clover a hectare.

On the lambing blocks the Griggs favour fescue, prairie grass and legumes over ryegrass .

On the shady face 20kg of Advance tall fescue and 2kg Phalaris a hectare were also in the mix. Plantain and chicory will be oversown after a winter thistle spray.

Dick Lucas, of Lincoln University, warned that prairie grass might last only five years.

"Seeds germinate but croak. I would be thrilled to be proved wrong that prairie grass can't reseed."

William and Duncan are planning to plant a brassica crop via air, into a steep sprayed-out gorse block.

"I can't see why it would fail if we do things properly," William says.

If successful, 300ha of similar shady hill country will go through a winter crop rotation.

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