14 June 2002

Bed em down well to cut hock injury

By Richard Allison

HIGH straw prices are forcing some producers to reassess winter housing, but the correct choice of bedding material is crucial to minimise hock damage.

Cubicles offer many benefits over straw yards, says SAC Dumfries vet Richard Laven. "Benefits include fewer cases of mastitis, lower labour requirements and less reliance on straw, which is useful in areas such as south west Scotland where straw is expensive."

But cubicle-housed animals are more likely to become lame, particularly with digital dermatitis and sole ulcers. To minimise this risk of lameness, cubicle comfort should be maximised by selecting the right bedding material.

The aim is to encourage cows to spend more time lying down and ruminating. Cows which stand for long periods are more likely to become lame. Excess standing will also cut milk yields and cow health may suffer, says Dr Laven.

"To determine which bedding material maximises cow comfort, research at ADAS Bridgets Research Centre investigated the effect of housing system on hock damage in heifers. Using cubicle mattresses, packed with chopped car tyres, resulted in less hock damage than rubber mats."

By week 26 of lactation, more than 80% of hocks on heifers housed on mats, which showed no damage at calving, were found to have severe damage. In contrast, less than 30% of hocks had severe damage when heifers were on mattresses, he says.

"While hock damage itself is not a problem, it is an indicator of how easily cows can lay in cubicles and level of comfort. A higher level of hock damage will indicate a greater lameness risk."

The reason for less damage could be that mattresses moulded to the cows shape, while mats were relatively hard with only the thin layer of woodshavings, used to keep the bed dry, helping to absorb shock, he explains.

But older cows are more prone to hock damage and further work is needed to ensure the benefits seen in first lactation heifers persist in later lactations.

Dr Laven believes cubicle mattresses are nearly as good as loose straw yards for minimising hock damage in heifers. "Producers replacing worn-out cubicle mats should consider changing to mattresses as they will often see benefits in cow health."

While there is an extra cost associated with mattresses, it is cheaper than having to replace cubicles to improve comfort. Many units have limited capital to invest and will be forced to make their system work.

Another alternative is sand. Dr Laven is convinced that cubicles with sand are more comfortable than those with mattresses. &#42