Trace Minerals and Lameness

Lame cows are a pain in the butt: - and in the wallet! An article in last month’s Dairying Today rightly pointed out that poor race surfaces, combined with forcing cows to walk too fast over stony patches, appears the major predisposing cause of lameness in New Zealand’s dairy cows.

Poor races result in trauma injury, with sole bruising and white line injury accounting for most cases of lameness. Foot rot or other foot infections are considerably less common, and laminitis, (more a problem with high-producing grain fed cattle), seems even rarer in NZ, (or may not be being recognised)..

The obvious answer is to fix up the races to provide a smooth comfortable walking surface. However, some farms experience an unacceptable incidence of lameness despite their races being in good condition. There may be a variety of reasons for this, but in some cases it is because of poor structural integrity and hardness of the hooves of the cattle.

In large herds particularly, cows have to walk a considerable distance each day. Consequently, there can be considerable wear on their soles which also predisposes them to sole bruising, haemorrhage and cracking. As I think most ladies will confirm, if you want to feel and look your best it helps to have good strong nails and avoid them becoming chipped or cracked.

Hooves are like nails; they need care and attention. This includes ensuring that the appropriate nutrients are taken in to provide for their strength and hardness. Considerable research has shown that the hooves of horses and the nails of humans are strengthened when the diet is supplemented with various minerals, including magnesium, calcium, zinc, and sulphur, and the substance, biotin. All contribute to the formation and maintenance of keratin, the main protein that provides strength and resilience to hooves and nails.

There is also evidence that supplementary biotin and zinc improves the hardness of cattle’s hooves. Biotin however, is expensive, and although useful for cattle, it has not gained popularity as a supplement for improving hoof quality.

On the other hand, zinc supplementation is widely used overseas to help maintain hoof hardness and quality, and supplementation for the same reason is growing in popularity in NZ. That zinc supplementation helps improve hooves and reduces the incidence of lameness is largely anecdotal in NZ, but there is research with amino acid complexed zinc that supports this benefit. For example, compared to non-supplemented controls followed over a 2 year period, zinc amino acid supplemented herds had significantly lower clinical and sub-clinical hoof problems, with lower incidence of sole haemorrhage, ulceration, and other foot problems.

I refer to a US trial using high producing herds where dietary and environmental factors were different to NZ conditions, so its relevance should be interpreted with caution. It would be interesting to see a similar trial conducted here. There are however, anecdotal reports from NZ farmers who have supplemented with amino acid zinc complex for the past 2 years, who consider they have fewer lameness problems than in previous years and that hoof hardness does seem better in their cows.

It must be remembered that any positive effect from either biotin or zinc, (or indeed any other supplement), on hoof hardness and quality, will take some months before it may be observable. These nutrients are only slowly incorporated into the new keratin of the hoof as it grows, and it may be 9-12 months before new growth includes the whole hoof.

However, if supplemental zinc is being used regularly to improve milk production, enhance immune responses, and help reproductive performance, an added benefit may be that herd lameness and associated problems may also be improved.

Certainly, the theory that zinc supplementation can improve hoof quality is sound, and I would be interested to hear from farmers who feel that lameness problems in their herd have been helped by any such long-term supplementation.

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