Road test tries out the best alternatives
Road test tries out the best alternatives
The design and maintenance
of farm roadways are topics
given a high priority at
Gelli Aur college farm in
Carmarthenshire.
Robert Davies reports
INTRODUCING rotational grazing at Gelli Aur College meant that extra roads were needed, prompting a trial of different track alternatives.
The existing network of cattle tracks was fine while a field set stocking system was used, but flexible access was required for the new grazing paddocks system introduced as part of a two-herd trial comparing the policy of going for maximum margin/litre with maximum margin a cow.
All options for moving 100 milkers were costed. Manager, John Owen, and his team decided that if surfaces such as tarmac or concrete were used roads would need to be 2.4m (8ft) wide. Estimated costs were £30 plus a running metre (£27/yd) and £16 a running metre (£14.40/yd), respectively. They decided that cows would move more quickly and safely if they installed the type of bark-surfaced 1m (3ft 3in) wide cow track developed by dairy consultant John Hughes.
This cost £10/m (£9/yd), including £6/m (£5.40/yd) for the two membranes and £1/m (90p/yd) for bark fill. The cows like the surface and Mr Owen wants to lay more tracks like this, but he questions whether the construction and maintenance costs can be justified.
Layer of bark
Instead, with 1000m (1100yds) of new tracks still required, he began experimenting this spring with an adaptation of the cow track idea. This saves £6/m (£5.40/yd) by avoiding use of two membranes. A thin layer of bark is placed over 15cm (6in) of large rounded stones, in which a plastic field drain is laid to take away rainwater.
Because the walkway is less comfortable than the conventional cow track it has been made 2.4m (8ft) wide to take account of any slower walking cows. By early June the stones, which were consolidated using a vibrating roller, were starting to rise through the bark in places. Though no feet problems had occurred, Mr Owen decided further rolling was necessary.
"Though the trial walkway is twice as wide as the cow track, it cost 30% less. In time we hope that the bark will rot down to form a sort of carpet surface over the stones," he says.
Now Mr Owen plans to experiment with another low-cost version requiring no excavation. A single 2m (6.7ft) wide membrane will be laid on grass and covered with 2m (6.7ft) wide cambered layer of a compactable washed stone product. Electric fencing will discourage cows from walking on the edges.
Best use of grazing
"We are aiming to get 6500 litres of milk from the cows, with more than 4500 litres coming from forage. Clearly we have to make the best possible use of grazed grass, which means providing roadways to ensuring good access. Tracks will give us greater management flexibility, but costs must be kept in check."
Half the college farms three miles of roads and tracks were made many years ago and were constructed of either tarmac, concrete or hardcore to carry machines and livestock. Mr Owen particularly likes tracks surfaced with river gravel, which are durable and relatively easy to maintain.
"If we had a source of similar stone on the farm we would probably have made the new roads we require in the same way," he adds.
To successfully use tracks that combine economy with cow comfort, Mr Owen believes it is essential to avoid predisposing cows to feet problems. This means regularly scraping slurry off concrete surfaces and having well designed comfortable cubicles that encourage cows to lie rather than standing with their back feet in the slurry channel.
It also requires regular feet care and good stockmen who can spot problems early. A contractor visits the farm monthly and the feet of every cow in the herd are checked at some time during the year. Cows that prove particularly susceptible to feet problems are culled. *
Cows at Gelli Aur College like the narrow bark tracks built using membrane, but John Owen is not sure the cost is justified.
John Owen hopes the bark will rot down on the wider bark track to form a carpet-like surface.