It’s perfectly natural to want a silver bullet that will instantly remove the threat of devastating health problems like laminitis but it’s just not that simple.
The classical laminitis stance is something you never want to see.
The latest proposed silver bullet currently popping up in mail boxes and on groups is a magazine article from 2016 regarding a vaccine developed in Canada. The headline was “Laminitis Vaccine Offers Horse Owners a Preventive Tool”.
The vaccine is against two exotoxins produced by Streptococcal bacteria which proliferate in the hind gut when there is an overload of grain starch or fructan. These exotoxins are believed to trigger the enzymatic cascade that breaks down the laminar connections in hind gut associated laminitis. In an experimental model the vaccine prevented laminitis in 20 out of 24 horses and reduced the severity in the remaining 4 animals. Formal testing for regulatory approval has not been done.
Sounds really promising so far but there’s one big problem. The vast majority of laminitis cases are caused by insulin resistance, not hind gut carbohydrate overload. Streptoccal overgrowth and exotoxin absorption are not involved so obviously protecting against those exotoxins isn’t going to work.
There is no guaranteed protection against pasture laminitis with an IR horse. There are times of the day, weather conditions and grass growth stages that are more likely to be safe than others but no guarantees because grass is a living tissue with sugar and starch levels in constant flux.
Well controlled IR horses are more likely to escape without problems if they accidentally get pasture access, or if you roll the dice and allow grazing when sugar and starch levels should be safe.
Good control requires hormonal normalization if the horse has Cushing’s disease/PPID (pergolide) and an IR appropriate diet with sugar and starch intake at less than 10% of the analyzed nutrients. Correct mineral amounts and balancing are also very important. Common deficiencies and imbalances which are involved with normal functioning and hormonal activity include magnesium, phosphorus, copper, zinc, selenium and iodine. If your hay was grown on alkaline soils, common in the mid West, adding chromium can be of benefit since uptake of this mineral is impaired in alkaline soil.
Acetyl-l-carnitine is a metabolite normally present in the body that supports insulin sensitivity in other species when supplemented. Jiaogulan is a Chinese herb that also participates in insulin responsiveness and supports normal blood flow to the foot in the face of the high vascular tone induced by IR.
It’s not as easy as a shot in the neck but correct nutritional support for an IR horse is your best defense against laminitis.
Eleanor Kellon, VMD