Feeding a low sugar, high fibre diet is correct, but why?
The problem is not sugar. Fibre is made up of sugar. Sugars are converted to glucose, the single most important energy provider in any species. Malfunction of this biochemical pathway – IR, EMS Cushings – do cause problems, even laminitis, but the same philosophy of feeding holds true. Fibre is fermented in the hindgut, generating volatile fatty acids (VFA) one of which (Propionic) is converted to glucose in the body.
The problem is the amount. There is a limit to the sugars that can be broken down enzymatically and absorbed in the small intestine. Absorbed sugars are utilized immediately or laid down as storage (unless there is the above malfunctions). Those that are not absorbed pass into the hindgut.
Large amounts of starch are fermented to lactic acid and this acidification destroys the hindgut fibre fermenters producing bacterial endotoxins. Absorbed lactic acid, endotoxins and nitrites (fermentation of high levels of protein in the hindgut) release oxygenating free radicals and, inflammatory agents, and vasoconstrictors which means they cannot be flushed away from the hooves.
Therefore the rule in feeding the laminitic horse is to ensure the intake of starch and sugars is not too high, the same for protein. The protein requirement for activity is only marginally higher than maintenance, and feeding extra to an active horse is not advisable.
For starch, how much is over feeding? Recommendations, based on research, are that a normal horse should not eat more than 4 grams of starch (or total sugars) for each kilogram of live weight, 2 for a laminitic. This equates approximately to a ration of 10% starch and sugars.
It is possible to choose feeds that are low in starch, low in protein and high in fibre. But this can be a hidden danger. The profile of the fibre is also important. Some fibres (cellulose for example)will not release lactate, but others can generate appreciable amounts.
Feeding the laminitic isn’t complicated and can be achieved if the above is borne in mind, leading to a few simple rules:
- Keep the daily intake of sugar/starch below 10%.
- Don’t over feed protein. A daily intake of 12% will suffice, even for the most active animal.
- Avoid raw starch. Bruising or crushing does not markedly improve digestibility, but micronizing does.
- Think about which fibre alternatives should be used. Sugar beet, alfalfa, soya hulls and oat hay give good VFA proportions, with sugar beet giving the lowest lactic level.
- Avoid too high an intake of fructans. We know about spring grass, but winter grass, if close cropped, can have higher levels as fructans are stored at the base of the grass stem.
- Feed a product recommended for laminitics. These have been researched to encompass the above points and will help maintain the correct hindgut environment, ensuring those bacteria that can cause harm will not be able to grow.
