20 November 1998

High protein can be tricky

THE Royal Agricultural Society of Englands equine event recorded its best crowd to date, of 14,000 over the two days.

The seminars attracted hundreds and particularly popular were those on nutrition by Dr Bill Vandergrift from Euro Vision, South Georgia, USA.

The US is far ahead of the UK in studying equine nutrition, and the UKs nutritionists have to rely on results emerging from the Kentucky Equine Research Centre and Euro Vision.

He revealed recent results on mineral use and how feed can effect hormone release. For instance growth hormone is affected by energy intake, which explains why well-fed young stock are susceptible to orthopaedic disease, where joints can overgrow and deform.

Dr Vandergrift showed that a grass-fed youngsters will have gently fluctuating levels of growth hormone, corresponding to grazing times. However when they are grain fed the peaks and troughs are significantly higher. "This explains the erratic growth," he said.

Erratic behaviour, influenced by the thyroid, may be a result of too much protein. And calm behaviour may be influenced by extra magnesium. He explained: "The recommended levels of magnesium, and most other minerals, for horses has come from cows.

"From anecdotal evidence we expect that there may be many differences. We have now found that the magnesium requirement is much higher than we thought it was."

In these behavioural examples thyroid activity is being effected. One way of combating the temperament problems associated with excess protein is to provide yucca. This absorbs ammonia, which is produced from the breakdown of protein. This means less urine is produced, which means there is less water and electrolyte loss, and less stress to the endocrine system.

Blue Chip feeds has used information from Dr Vandergrift to produce a supplement for competition horses, Blue Chip Pro, which has extra magnesium, copper, iron and yeast. The higher mineral levels are also in Shipston Mills racehorse mix.

&#8226 Contacts: Blue Chip (0114-2666 200); Shipston Mill (01608-661411).

Seminars on nutrition attracted large audiences

at the National Equine Event, reports Tamara Farrant

who heard how well fed young stock can be

susceptible to orthopaedic diseases

Dr Bill Vandergrift: Magnesium requirement is much higher than we thought.