Laminitis Conference part 1

[bellajack]

The Royal Veterinary College Laminitis Conference 24th May 2007

I attended this conference under false pretenses as it was really intended to inform Veterinary Surgeons of the results of the latest international research on Laminitis with speakers from both here and abroad, principally USA and New Zealand.

I have summarized the main information as I understood it, but some of it was highly technical so I apologise for any inaccuracies. I think that I understood most of it and have copious notes, both my own and conference literature, so if you want anything clarifying I MAY be able to do so.

There was a lot of ground covered, so I will post this in installments and get it all out asap.


Starch Sugar and Fructan

The speaker for this section of the conference was:
Annette C Longland BSc PhD DIC. She gained her PhD in plant pathology and after a post-doctoral fellowship has worked on the detailed chemical analysis of forages and their fermentation by equid and ruminant microbiota.

Plant carbohydrates include Structural and Non Structural Carbohydrates.

Structural carbohydrates are trapped in the cell wall of the plant and are easily digested in the fore gut – no problems.

Non structural carbohydrates are the ones in the cell contents and consist of starch, fructan and simple sugars.

Starch is stored mainly in the seeds of plants and so over consumption is easily avoidable by reducing/avoiding feeding cereals.

Fructan accumulates in the leaves and stems of grasses and can reach substantial levels (as high as 400gms fructan per kg dry matter) with some of the highest levels recorded in a cold sunny January.

The simple sugars in pasture grasses are sucrose, fructose and glucose in order of predominance but these occur in much lower amounts than fructan.

Oat starch is fairly digestible in the fore gut unprocessed (85%) but barley is poorly digested (21%) along with other cereals and they should be micronised or extruded to improve fore gut digestibility if they must be fed at all.

Fructan is not digestible in the fore gut and passes into the hind gut where the entry of large quantities can cause colic and laminitis.

The simple sugars can be digested in the fore gut but large quantities may exacerbate insulin resistance and add to the risk of laminitis. More on signs of insulin resistance later but most Dales Ponies would be suspect on appearance.

Amounts of fructan in grass varies greatly from season to season, day to day, and hour to hour. Also fructan levels vary in varieties of grass (and can be high in weeds, esp. Dandelions). Grass seed mixtures suitable for horses at risk from laminitis are being developed and may be available soon, but are not yet on the market.

Fructan levels depend on the amount of production (photosynthesis) compared to the rate of utilization (plant growth) and variations of as much as 46% increase by afternoon as compared with morning have been recorded. Dull warm days are safer than sunny days and laminitis cases have been shown to rise in proportion to hours of sunlight, regardless of temperature and rainfall.

The fructan levels in hay are equally difficult to predict and will vary according to, among other things, whether the hay was cut in the morning or afternoon. Hay made late in the season, after seed dispersal, and cut in the morning, will be safest for at risk horses.

Haylages, Particularly quite wet ones, are lower in fructans generally than hay but are much more palatable so the amount fed needs to be carefully monitored.

TAKE HOME MESSAGE.

There is no way you can guess on the fructan content of grass or hay by looking.
Remember that it is the overall amount of fructan consumed that is important, so even horses eating grass/hay low in fructan may be consuming a lot if they are eating large amounts of grass/hay.

[bellajack]

The Royal Veterinary College Laminitis Conference. 24th March 2007.

Advice for managing horses known to be at highest risk of developing laminitis (those who have had it before) and horses of the type likely to be at high risk of developing it (overweight and/or cresty neck and localised fat deposits partic. around sheath or udder - signs of insulin resistance. Advice as given, word for word, by:

Pat A Harris MA PHD Dip ECVCN Vet MB MRCVS. Qualified Cambridge Veterinary School
in 1983.
Adjunct Professor of Equine Studies at Virginia State University and European Specialist in Veterinary Clinical and Comparative Nutrition. President of The British Equine Veterinary Association 1999.

Due to the highly variable and unpredictable nature of Fructan accumulation in pasture, animals predisposed to laminitis should preferably be denied access to grass pastures during the growing season.

If some grazing is unavoidable, turn animals out very late at night or very early in the morning removing them from the pasture by mid morning at the latest as fructan levels are likely to be at their lowest at night to early morning.

Avoid pastures which have not been properly managed by regular grazing or cutting as mature stemmy grasses may contain more fructan as it is stored in the stem.

Avoid turning horses out to pasture during late spring when Water Soluble Carbohydrate/fructan levels are rising.

Do not turn horses out onto pasture that has been exposed to low temperatures in conjunction with bright sunlight, as occurs in the autumn after the autumn flush of growth, or bright, cold winter days as cold temperatures will reduce grass growth resulting in the accumulation of fructan.

Do not allow horses to graze recently cut hay stubble as fructan is stored predominantly in the stem.


Next installment to follow shortly but basic message is to feed hay soaked for 30mins to remove 50% of Water Soluble Carbohydrates, or haylage if you can slow consumption sufficiently (treble haynets) and chaff based feeds with a high quality vit/min supplement. If cereals must be fed they should be processed to enhance digestibility in the fore gut (micronised or extruded). Also weeds can be very high in fructan.

[greydales]

bellajack said:

The Royal Veterinary College Laminitis Conference 24th May 2007

. Also fructan levels vary in varieties of grass (and can be high in weeds, esp. Dandelions)

Oh dear ......



think maybe I ought to concrete my fields over!!!!!!!

Thanks for that bellajack, lots to take in (and panic about ;D)

[harveydales]

Thanks so much for taking the time to write this all out and post. Brilliant! I will print it all out and read it again.

It never crossed my mind that Dandelions could be a problem as regards fructans levels!

I will be very interested in what grass seed mixes are developed as breeding new grass varieties and producing mixes was my profession many years ago. I had always hoped our hayfield, which is ancient meadow with lots of different grasses in but few Rye grasses, would produce safe hay but now I'm not so sure. We rarely cut before 11AM as it is generally too damp here. However, it does confirm that my gut feeling was right in that my ponies are safer grazing small amounts of the very short stressed grass rather than large quantities of long grass.

Thank you very much - fascinating reading. I'm looking forward to the next installment!

[bevbob]

Thanks from me too Bellajack, glad to see you back too.

[PonyGirl]

I can't thank you enough for this posting. I had to print it and read it over and over. Thank you so much.

[bellajack]

No problem. Hope it helps. They did say at conference that laminitis is now THE most common cause of lameness in USA,so you are even worse off than us - 2nd most common after foot infections here.