my horse with heaves

Question
Hello,
i have a 12 year old mare that had gotten diagnosed with the heaves about a year ago, but we had her on pasture for about 6 years but she still then coughed towards the last 2 or 3 years.

Last year, she started coughing really bad even out on pasture and we had a alfalfa bale out for her and the other horses. and then my father had to move (he was the one that kept her for me)so after my dad moved we moved Lucy down only a couple of miles from me, and we gave her alfalfa and had wet it down she didn't cough as bad but she still did cough. we had even gave her 500ml of calcium tablet and put them in her feed that seemed to help for a little while.

After we had found out that she had the heaves we had started giving her grass hay but it had no nutrients in it, and now she is loosing weight and we think it is because of the hay. my question is, can we start giving Lucy alfalfa again, if we wet it down increase on her antihistamine. And we give her omolene 400 in the morning and normal sweet mix in the evening, does the omolene 400 help her too?

Answer
Hi McKenzie,

Thank you for your question.  This is a bit of a difficult situation.  Its interesting that your mare developed the heaves despite being kept on pasture.  The heaves are normally the result of dust-laden environments; either from dusty hay of from a closed-in dusty environment.  That fact that she lives outdoors on pasture makes it seem odd that she's developed a cough from dust.  I'm wondering, have you tested her for allergies?

Grass hay is traditionally less nutrient dense than alfalfa based hay so some weight loss with the switch would make sense if the rest of the diet was not adjusted for energy content. You have a couple of options for your mare;  go back to feeding alfalfa hay but watering it to cut down on dust, or continue to feed grass hay and balance the rest of the diet (using supplements) to help her maintain condition. If you need help with balancing a ration, I can help you.  I would need your mare's body weight, workload and the information from a hay analysis.  

As a side note, grapeseed extract is a great antihistamine for horses and Basic Equine Nutrition (a Canadian company) makes a great product for horses.

I would make a suggestion, and the reasoning would be a bit hard to explain but I'll give it a shot.  I would suggest that you switch off the Omolene 400 and other sweet feed, and start feeding a fiber and fat based complete feed like Purina's Equine Adult.  There are some instances when starch-rich diets can lead to higher than normal blood histamine levels.  There is a bacteria in the hindgut of the horse that under abnormal conditions (not something we can visually detect, more internal) can convert a normally useful amino acid into histamine in the cecum and if the pH of the cecum falls to a certain level the histamine can travel across the cecum wall and into the bloodstream where it causes all of the histamine related side effects.  Two ways of stopping this cycle are to remove starch from the diet and get rid of the bacteria that causes the problem. You can get rid of a lot of dietary starch by switching to a high fiber and high fat feed.  Getting rid of the bacteria that causes the problem is much more complicated, although I strongly suspect a product like Alltech's LifeForce Formula can help.

I hope that helps.  Send me the mare's information if you would like me to balance a ration.

Thanks, Corlena