Causes
Laminitis has multiple causes, some of which commonly co-occur. These causes can be grouped into broad categories.
Endotoxins
Carbohydrate overload
One of the more common causes. Current theory states that if a horse is given grain in excess or eats grass that is under stress and has accumulated excess non-structural carbohydrates (NSC, i.e. sugars, starch or fructan), it may be unable to digest all of the carbohydrate in the foregut. The excess then moves on to thehindgut and ferments in the cecum. The presence of this fermenting carbohydrate in the cecum causes proliferation of lactic acid bacteria and an increase in acidity. This process kills beneficial bacteria, which ferment fiber. The endotoxins and exotoxins may then be absorbed into the bloodstream, due to increased gut permeability, caused by irritation of the gut lining by increased acidity. The endotoxaemia results in impaired circulation, particularly in the feet. This results in laminitis.
Nitrogen compound overload
Herbivores are equipped to deal with a normal level of potentially-toxic non-protein nitrogen (NPN) compounds in their forage. If, for any reason, there is rapid upward fluctuation in levels of these compounds, for instance in lush spring growth on artificially fertilized lowland pasture, the natural metabolic processes can become overloaded, resulting in liver disturbance and toxic imbalance. For this reason, many avoid using artificial nitrogen fertilizer on horse pasture. If clover (or any legume) is allowed to dominate the pasture, this may also allow excess nitrogen to accumulate in forage, under stressful conditions such as frost or drought. Many weeds eaten by horses are nitrate accumulators. Direct ingestion of nitrate fertilizer material can also trigger laminitis, via a similar mechanism.
Colic
Laminitis can sometimes develop after a serious case of colic, due to the release of endotoxins into the blood stream. Refer to Carbohydrate Overload.
So, here is more research I found, that the grass grazing in combo with alf hay that the vet called for, is for the ulcer care. I guess that makes sense...here is what I found:
ReplyDeleteHorses at pasture graze almost continuously, and at the same time they produce saliva. "Acid in the stomach is produced on a continuous basis," he says. "It doesn't stop. So the constant eating is a help."
Tom Trotter, MS, general manager of Progressive Nutrition in Iowa, says horses are not like humans in how their digestive systems work. "We salivate mainly when we eat, and certain enzymes are produced when food enters the stomach. Horses are producing digestive acids all the time. So if a horse has an empty stomach, he is at risk for ulcers," says Trotter. "The most effective way to prevent ulcers is to allow horses full-time access to hay or pasture. This also gives the animal something to do, which relieves stress and boredom. When we do consultations on farms, one of the first things we do is check to see if there is hay in the stall."
A&M discovered that alfalfa hay was more efficient in buffering against stomach ulcers than grass hay, due to the higher level of calcium (and protein) in alfalfa. The extra protein and calcium can both act as potential buffers for stomach acid."
Oh - darn! That poor horse - yes, colic can bring on laminitis, because of the toxins that can be released into the horse's system. It's actually pretty common. If you trust your vet, then follow their advice. Horses are amazingly fragile, indeed. Keeping my fingers crossed for you and him!
ReplyDeleteTrue. Stress due to colic and other things can bring on laminitis. I'm no vet either but I very seriously doubt that the grass did it. I've heard of mares having laminitis following a difficult foaling, too. Poor guy. Hope all is well soon.
ReplyDeleteI am not a vet either, but we have had a ton of luck with grass and alfalfa for ulcers. Basically, whatever these horses are stressing from on the track, the natural environment of almost 24/7 turnout and good quality alfalfa seems to "relax" the tension and bad acids. As far as laminitis - in the past we have had improvement with slow, consistent, daily walking(leading) on soft ground. (Start in small increments and work up to more). Just like a person with gout who has had too rich food, laminitis seems to improve with slow even exercise - this can increase blood flow and regenerate the good cells to that area.
ReplyDelete