We ran our Murray Greys at Picton for about 35 years and never had a problem with feet despite keeping many cows into their teenage years. The herd was fairly early maturing and we had a couple of dam lines that tended to be roly poly fat. The pasture at Picton was essentially C4 tropical type grasses like paspalum, kikuyu and natives such as kangaroo grass.
When we moved the herd to Binda in the Southern Tablelands about 15 years ago we started to have trouble with feet. There were two main problems. Firstly, some animals developed long claws, as in the examples below.

bad-feet

Problems occurred in some older cows that had been quite sound at Picton but a proportion of animals born at Binda developed problems when quite young. We had problems in a group of heifers purchased from further west. Their feet looked good on arrival and the breeder, who we trust, said their were no feet problems in their background.

Secondly, we had many cases of foot abscesses which we had rarely encountered at Picton. Having to walk affected cows back to the yards for treatment was time consuming. We think that walking them on newly built gravel roads may have predisposed them to further infection. Some foot abscesses proved difficult to treat and a couple were eventually culled because of persistent lameness. Other cows developed deformed claws as a result of the infection.

Initially we thought that the soft ground and more muddy conditions at Binda was responsible for the change. The ground at Picton was generally hard and dry and the feet maintained a good shape. We considered that when the foot anatomy was suspect, with low heels, the softer ground at Binda allowed the feet to grow longer.

We sought advice from local experienced cattlemen. Some described feet problems that developed in cattle brought in from the North Coast. The conclusion was that it was caused by our softer pastures.

Our interest in recent research in laminitis in horses has provided some interesting information of relevance to cattle. It has now been shown that laminitis in horses is triggered by elevated levels of insulin which occur when horses are fed diets high in sugars or starch. All previous theories about toxins can be disregarded. Furthermore there is work to show that cattle have the same problem although in beef cattle it is more commonly subclinical. For a description of the condition see:
txanc.org/wp-content/uploads/2011/08/BovineLaminitis.pdf
(Note that this article was published before the role of insulin was discovered.)

Below are diagrams of a normal and a laminitic foot

diagram-laminitic-footdiagram-normal-foot-300x185

A high sugar level in the blood causes a spike in insulin levels which can create a chain of events resulting in a breakdown of the attachment between the pedal or claw bone and the hoof wall. There is a separation between the pedal bone and the hoof wall. In acute cases the pedal bone may penetrate towards the sole and a sole ulcer will result. If the pedal bone is retained at the normal angle the hoof grows out more parallel with the ground.

laminitic-foot-section-624x400

So what does “fat” have to do with feet problems?
The problem of insulin resistance causing obesity in humans has been well documented. Individuals with insulin resistance have a prolonged rise in the level of insulin after getting a rise in blood sugar. The insulin drives the conversion of the sugar into fat storage. Horse owners know well that horses and ponies that are good “doers” are the ones prone to laminitis or founder. These horse often develop fatty deposits along the crest of the neck. The same association appears to happen in cattle except that the fatty deposits tend to be around the tail and pin bones.

We have noticed a higher proportion of foot problems in our “good doers” and those with very high fat EBVs. Not all animals with high fat EBVs have bad feet but the tendency is there.

So how is it that the “softer pastures” lead to feet problems?
In the Tablelands there is a much higher proportion of C3 temperate species like rye grass and prairie grass which do not persist in warmer areas. These grasses have a relatively higher concentration of non structural carbohydrates (NSC) in their stems and leaves which leads to an increase in blood sugar.

We have tested our pastures, hay and silage to determine the high and low risk pastures for our horses. Rye grass can easily contain over 25% NSC which is very risky for horses. Now we realise that this is great for lactating cows but not so good for cattle if they do not have a high requirement. Of particular interest is the high NSC content in cereal hay, particularly if it has been baled because frost or drought has spoilt the grain. During growth the plant stores sugars in the leaves and stem ready to use for grain formation. When frost or drought prevents the formation of the grain the stems and leaves contain high levels of sugar. We had a number of problems in the feet of a mob of heifers fed on frosted cereal hay during the 2006-07 drought. Now we know why.

Another cause of insulin induced laminitis is the feeding of a high proportion of starchy grains in the ration. Starch is broken down and absorbed as sugar which results in insulin production. Many animals on high grain diets break down in the feet and it appears that high insulin is the root cause of the problem.

Bad feet – not a simple problem.
Bad feet are caused by a combination of factors. Structural problems in the legs or pelvis will accentuate uneven wear and misshapen feet. Nutritional factors such as high NSC will increase insulin which in susceptible animals will lead to subclinical laminitis and misshapen feet, sole ulcers and predisposition to infection. So there are anatomical, metabolic and nutritional aspects contributing.

We hope this explains the problem.

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