Low thyroid … environmental link?

Since last fall 4 horses, geldings and mares, aged 10-14 years, Arabians, arabian crosses, and QHs have come up with low thyroid levels. They also had low white blood cell counts, low red blood cell counts, and high glucose levels. They had muscle wasting along the ...Since last fall 4 horses, geldings and mares, aged 10-14 years, Arabians, arabian crosses, and QHs have come up with low thyroid levels. They also had low white blood cell counts, low red blood cell counts, and high glucose levels. They had muscle wasting along the ...

Story originally posted by: Michael Lowder, DVM, MS

Dr. Lowder:

Since last fall 4 horses, geldings and mares, aged 10-14 years, Arabians, arabian crosses, and QHs have come up with low thyroid levels. They also had low white blood cell counts, low red blood cell counts, and high glucose levels. They had muscle wasting along the topline, pot belly, and winded easily with exercise. No weight changes. No diet changes during this time other than additional hay feeding after killing frost. They are not on fescue pasture or fescue hay. Hay is local grown timothy/orchard grass. Pasture is same. They are on low concentrate, high forage diets. No alfalfa. These horses are on adjoining farms using the same hay source and feedmill source. Water is well water and filtered for minerals and bio hazards. Soil and water are acidic. Soil is heavy clay to gravel. Several other horses in the same county are experiencing similar problems. None of the horses are related. Horses are well cared for and receive all recommended standards of care. Could we be experiencing an environmental cause? Where would you suggest we start looking?

Thanks

Hello:

There is really no such thing as a horse being hypothyroid. Ok, there is … but the chances of you haveing one case much less four is rare. Horses are frequently feed thyroid supplement which increases the metabolism of the horse and thus it looks better (weight loss) and people (vets too) think that it is doing something great. First, how low is the WBC? Second, I would repeat the blood work to confirm. Third, if the WBC is low then I would make sure the lab is doing its job (may consider sending samples to different labs. Both conditions (low EBC and high blood glucose) could be due to stress. Make sure you have not changed anything in the environment. Double check yourself. You may also consider having a complete biochemistry test including minerals evaluated.

Good Luck,
Dr. Lowder