It is normal to get more lameness in front feet at this time of the year than at other times. Cows are bulling and when they come off the ridden cow they land on their front feet. This produces more trauma than normal walking. There is no 'suspension' in the front feet, in common with the feet of humans. But whereas a human can create 'suspension' by bending the knees, a cow can't do that, so enormous pressure comes on the locomotion apparatus when they do land on their front feet.

Did you know that you would break your legs if you jumped off the back of a truck with your legs straight? The amount of pressure the average person would put on their feet by such a jump is about 1000kg. No wonder major damage would occur if you kept your legs straight. Similarly a lot of force goes on the front feet of a cow when they ride another cow. A lot of the lameness in the front feet is ligament damage but we do get more hoof problems as well.

This does not mean this sort of lameness is caused only by physical force. Again, the cow must have weakened claws from laminitis and then physical force will make the problem worse resulting in lameness. If it was caused only by physical force we would see a lot more problems because, whereas most cows come on heat, not many go lame in their front feet. We can't stop cows riding each other. We actually don't want to stop it so we have to look at the stress levels on the cows and make sure tracks and holding yards are stone free.

Lameness in bulls is slightly different. A few things are happening with bulls when they arrive on the farm and when they go with the cows. For one, the environment is totally different – different food, routines and lifestyle. I don't think the testosterone levels have an effect on laminitis but all the other changes currently do. We have some physical problems as well. The wear pattern in animals that walk only on pasture is different from animals that walk on hard surfaces.

When bulls suddenly walk on hard surfaces their hooves wear faster, and it will take about six weeks for a bull to adjust the growth rate to the wearing rate, so many bulls end up with thin soles. The solution to this is to have enough bulls to be able to rotate them and make sure you use them in short bursts.

Hoekstra is managing director of Veehof Dairy Services Services in New Zealand.