23 August 2002

Keep bedding straw dry

By Richard Allison

ENSURE straw bales bought for bedding dairy cows are dry and consider using a mechanical straw shredder this winter to help minimise mastitis.

An MDC-funded project across four dairy units revealed that many straw bales used for bedding cows were too wet, says Cheshire-based dairy consultant John Hughes.

"About half of bale edges and more than one-third of bale centres tested exceeded the target of 15% moisture. Some bales contained more than one-third water."

Using wet straw will lead to poorer cow cleanliness, as wet beds cant keep livestock dry and clean. The herd with the lowest incidence of mastitis in the study, at 10-13 cases/100 cows, had the cleanest cows and good dry straw beds.

He advises checking straw moisture with a Balemaster probe to avoid buying wet straw bales, which appear dry on the outside. "Aim for 15-20% moisture or less."

Bales with wet edges and dry centres indicate a problem with storage or transport. Ideally, straw for bedding should be stored undercover, but where space is limited, bales can be successfully stored outside.

"Choose a hard flat stone surface and place bales in straight-sided stacks, round bales should be placed on their ends. Dont cover the stack with a plastic sheet as they rarely work. Birds will soon damage it causing water to drain down in the centre of the stack."

Instead, cover with a layer of bales to be sacrificed, which can be replaced to protect remaining bales, says Mr Hughes.

Storage policy at Rodbaston College, Staffs, is to store large square bales under cover, says its farm manager Ian Sanday. "Square bales rapidly deteriorate when wet."

However, round bales are able to withstand outside storage better than large square bales, says Mr Hughes. "They are able to hold out the wet more effectively."

Mr Sanday believes good straw storage is critical when using a chopper or shredder to bed yards, as wet straw blocks the machine more readily.

The project also found that using a mechanical straw shredder benefited cow cleanliness, says Mr Hughes. "It produced a drier and fluffier surface which has a cleaning effect on cows walking around the yard."

It is impossible to provide clean beds in large yards by manually teasing out bales. Hollows form in the bed, which become filled with dung, contaminating cows.

Mechanical choppers also cut straw use by nearly 60%, as found last year in a farmers weekly and Rodbaston College trial. "It showed the cost of the chopper would be swiftly recouped by savings in straw and labour costs."

After the study, the chopper was bought with more straw now being sold to the colleges equine unit. Even with lower straw prices this summer, Mr Sanday believes there is still an economic benefit in purchasing a straw chopper.

"We were expecting an increase in somatic cell counts as spring calving cows were housed in straw yards for the first time. But cell counts remained at about 150,000-180,000 cells/ml."

Mr Sanday believes using a straw chopper to bed cows daily helped to keep cell counts under control, when switching from cubicle housing to loose straw yards. "Cows were certainly cleaner and straw beds seemed to absorb water and dung more effectively."

Dung consistency is also an important factor affecting cow cleanliness and mastitis, says Mr Hughes. The herd in the study with the lowest mastitis incidence was fed a ration which rarely caused loose dung.

He believes bedding stock with good quality barley straw helps encourage animals to eat more straw, leading to drier dung. &#42

STRAW BEDDING

Check straw moisture.

Good stack design.

Mechanical shredder.

&#8226 Check straw moisture.

&#8226 Good stack design.

&#8226 Mechanical shredder.