Grass-only maintenance may boost spring growth
Grazing beef cattle over
winter with minimal
supplementation may help to
boost growth rates at grass
according to new Irish research.
Emma Penny reports
WINTER grazing, providing a maintenance ration for beef cattle, could cut over-wintering costs and enhance compensatory liveweight gain when cattle go to grass in spring.
A trial at Grange, Co Meath – beef centre for Irish advisory and research service Teagasc – is examining whether this system is practical, profitable and welfare acceptable.
Eddie ORiordan, head of the centre, explains that providing cattle with a grass only maintenance diet over winter could help maximise spring compensatory growth, producing cattle that are little different from those fed over winter, but at much lower cost.
"It is difficult to know how much cheaper production from grass would be – perhaps two-thirds of the cost of housing overwinter.
"But that saving has to be set against tighter grazing in autumn to ensure there is enough grass on farm over winter, and any loss in spring grazing must also be considered. The jury is still out as to whether it is much cheaper."
Trials at Grange last year compared cattle grazed from Jan 1 to Mar 23 and fed about 2kg concentrate with housed cattle fed silage and concentrates. All cattle weighed about the same at the start of the trial.
"At the end of the winter, there was an average 30kg difference between the two groups. But when they were turned out, the housed cattle lost about 15kg initially, while the others gained weight straight away. After three weeks both groups weighed the same, and when steers were slaughtered at 20 months all averaged 345kg carcass weight."
This year, the trial has been extended. Four groups of 10 cattle are being run, receiving: Only grass for three to four hours a day, three to four hours grass a day plus 2kg concentrate, housed full-time with ad lib silage, housed full-time with ad lib silage plus 2kg concentrate.
"The two grazing groups are allowed three to fours hours of access to set herbage levels each day, and are housed for the remaining time. The aim is to maintain pasture intakes at 4kg dry matter a head a day, although this has been increased to 5kg DM a head a day recently.
"We have wintered 20 yearlings on 7.5ha over three months so far. When the cattle are turned out into a paddock it is completely defoliated within three to four hours, but the grass seems to recover very well. Being smaller cattle, they also cause less sward damage than cows."
Dr ORiordan admits that he expected the cattle receiving only grass would be skin and bone by now, but says that they are in reasonable condition.
"I think we will find that the wintering system has little effect on finishing. There may perhaps be a 10kg difference between the maintenance only ration and the ad lib silage plus concentrate ration, but that will be more than compensated for by greatly reduced costs."
But he admits that he has reservations about the system. "The first is that cattle have to be moved every day, which is time consuming.
"Producers might also wonder whether it is feasible on farms without infrastructure such as tracks, but we have managed by sacrificing an area for access. Although it looks messy at the moment, it is likely to recover well."
Dr ORiordan is also concerned about possible knock-on effects of winter grazing. "The biggest liveweight gain is obtained from spring grass. I do not think there is any point in jeopardising that, so winter grazing would have to be very carefully planned."
Carrying over grass from one season to the next may also be more difficult than in the dairy herd, he concedes. "Beef cattle are always growing – there is no rest like the dry cow period in dairying, when requirements reduce."
But those concerns aside, he believes winter grazing or similar simple systems have a place in beef production.
"The cost of housing is huge. Perhaps we should be looking at simpler systems where cattle are on hard standing with bales and limited access to grass, but welfare and environmental consequences will have to be assessed carefully." *
Winter grazing could reduce beef production costs with little impact on finishing, but care must be taken not to jeopardise spring grass availability, warns Eddie ORiordan.
• Young cattle.
• Compensatory growth.
• Cost savings possible.