Cow lameness could be higher than 10 per cent a year nationally and cost dairy farmers an average of $500 for each case of a cow out of production.
Accurate figures are not kept for lame cows because not every incident is reported, there can be repeat cases for the same cow and the extent of lameness can vary.
DairyNZ animal husbandry extension specialist Anna Irwin said lameness was more difficult to measure than mastitis or other animal health issues because it was not routinely measured by all farmers, had different treatments and few cows needed medical treatment. "We have industry estimates of somewhere around 10 per cent and it could be as high as 15 per cent and that's incidents for the whole year."
This does not mean that 10 per cent of the national herd was affected by lameness as some cows would have repeat problems.
However, lameness could add to farm working expenses and no farmers wanted to see their cows suffering, she said.
"It varies individually for every farmer and depends on their factors, but it's around $500 a cow just for one lameness incident. We used to think it was $200 but we think $450 to $500 is a better estimate so it's quite high and can be minimised."
A lame cow is unable or finds it difficult to travel to milk sheds and can find it difficult to eat grass or be available for mating.
Lameness peaks from October to March and early in the season cows may have soft hooves which can come under pressure during mating. Later the hooves might be thinner from wear on cow lanes.
Irwin said lameness could be influenced by the quality of lanes, wear in large yards, and damp paddocks.
Good management and staff training to allow cows to walk at their own pace and regular maintenance of cow lanes could help prevent lameness, she said.
"When we talk to farmers money is a factor, but the main thing is the time it takes and it's a welfare issue because people don't want to see lame cows."
Detecting lameness early could also prevent hoof problems from deteriorating and allow them to recover faster.
Cows lame from white line disease needs their hooves lifted and treated, usually by trimming and ensuring they are not placing weight on the hoof. Cows with foot rot might need antibiotic treatment with pain reduced from anti- inflammatory injections or a foam hoof block.
Lameness can also occur from hooves bruised on hard surfaces, footrot in damp conditions and infection setting in from bacteria as well as abscesses.
Irwin said heavy use tracks next to the dairy shed were a source of lameness and needed to be well drained, well compacted with a suitable surface, ideally lime, and not too steep.
Cows also needed enough space to manoeuvre in yards - about 1.5 metres to rotate freely, she said.
DairyNZ has a Healthy Hoof programme and upgraded lameness scoring in 2012 to help farmers detect lame cows with a scale from 0 to 3. A lameness cost calculator attached to this factors in treatment, labour, loss of production, reproduction and culling costs.
A track or lane should have a camber of 3 per cent to 5 per cent and be wide enough for herd access especially near the dairy shed.
The gradient should be less than 10 per cent.
Have a well-formed and compacted base, with suitable top-surface such as lime rock.
Tracks made boggy during wet spells can be stabilised with shingle.
The transition between race and yard can be a problem zone. Ensure it has good drainage and compacted material or use concrete.
Remove stones on the yard or feed-pad and eliminate slippery surfaces by grooving concrete and rubber mats at entry and exit points.