The main factors implicated in causing lameness are as follows:
- Calving. At calving, horn growth slows down and almost stops, but the rate of wear increases. Increased wear occurs because the cow spends more time standing. Also for the two weeks before calving until two weeks after, there is excess movement of the pedal bone within the hoof, predisposing the corium to damage. This leads to lameness due to sole ulcers and white line disease some 2-3 months later. Many studies have shown that the incidence of lameness peaks 2–3 months after calving.
- Excess Standing. Cows stand to be milked, stand to feed, stand to drink and stand for social interactions. The majority of social interactions occur during the first few days after cows are mixed, where there are approximately 10 aggressive interactions per hour for the recently mixed animal. The high-yielding cow has to stand to eat for some 6-8 hours per day; even longer if there is inadequate space at the feedbunk.
Cows should not be made to stand for half an hour after milking to allow the teat end to close. They should be allowed to walk back past fresh or pushed-up feed. If they walk past and want to lie down, then that is what they should be allowed to do. Milking times should be examined to make sure that cows are standing for the minimum time possible. The fresh calvers are particularly susceptible to long standing times and it may be appropriate to have a fresh group, so that cows in the 1-2 weeks after calving can be brought in for milking as a separate group at the start of milking to minimize standing time.
- Free stall comfort. Free stalls should be comfortable and allow the cows freedom of movement. Ideally the neck rail needs to be at least 4 feet (and preferably 4 feet 6 inches) high, but the loop at the rear of the free stall should be no more than 22 inches above the bed, otherwise cows will lie diagonally and this will lead to soiling of the bed.
- Free stall Bedding. Even if mats and mattresses are used, bedding is vital, but obviously if mattresses are in use the quantities of bedding required are less. On mats, 1 kg of sawdust or 1.5 kgs of straw should be used. On concrete, 2 kgs of sawdust, 2-3 kgs of straw or 8 kgs of sand are appropriate.
The small amount of bedding that falls off the surface of the free stall and into the passage is of considerable value. It acts as a cushion as the cows reverse out of the free stall, it acts as a drying agent within the passage and it also acts as an anti-friction agent when the cow swivels on her foot as she reverses out of the free stall. The 5kg/cow/day of sawdust in the free stall passage used by some producers makes an ideal floor surface.
- Heifer rearing. It is vital that heifers should be reared in free stalls so that they know what to expect after calving. They should also be reared at least partly standing on concrete so that, by the time they calve, they have learned how to walk on a slippery surface. Concrete produces some trauma to the bottom of the foot and this then stimulates the growth rate of the sole. Hence after calving, heifers reared on concrete have a thicker sole than those reared on softer surfaces.
- Diet. It is important to avoid diets that produce acidosis, as rumen acidosis reduces the rate of biotin synthesis. In older cows, where the rate of white line disease is higher, studies have shown that supplementation of concentrate with biotin can produce a four-fold reduction in the incidence of lameness caused by white line disease. High fibre transition diets are becoming very popular because they stimulate good rumination without overfeeding. Ideally cows need to stay on this ration for the first week post-partum, until they have recovered from the trauma of calving.
source: Roger Blowey, Nova Scotia Dairy Focus 2008