This is a particularly distressing recall. It involves horse feed that was distributed to four states that could “possibly” be contaminated with a feed additive that is deadly to horses. The worst part? There is no antidote.

First, the recall:

Bartlett Milling Company Issues Recall of Horse Food

FOR IMMEDIATE RELEASE – October 31, 2014 – Bartlett Milling Company has initiated a limited recall of certain horse feeds due to potential Rumensin contamination. The products were distributed to customers and retailers in North Carolina, South Carolina, Tennessee and Virginia.

Rumensin contamination can result in health problems, including mortality, in horses.

The products and lot number involved in the recall are:

50 lb. bags of Bartlett Pasture Horse 10 Feed – Lot 288

50 lb. bags of Cleveland Carolina Champion Horse Feed – Lot 288

The recalled products were packaged in typical brand-specific feed bags. Lot numbers are printed on the front and back of each bag.

Retailers have been contacted and instructed to immediately withdraw from sale the recalled product and to notify customers who purchased the product. Customers should discontinue feeding the product immediately. Customers who purchased this product should return remaining bags to their retailer.

For more information on the product recall, contact Bartlett Milling at 1-800-438-6016 from 8AM to 5PM Monday through Friday. Contact Bartlett at 1-336-655-1840 outside of regular business hours.

This recall is being conducted with the knowledge of the North Carolina Department of Agriculture & Consumer Services and the United States Food and Drug Administration.

Now, about the drug, Rumensin:

Monensin (Rumensin—Elanco) is produced as an additive for feeds for ruminants and is commonly used as an additive in cattle and poultry food – and is often added to drinking water to prevent coccidiosis on dairy farms.

The problem, however, is that horses are extremely sensitive to monensin poisoning. The LD50 (lethal dose) for monensin in horses is 2 to 3 mg/kg body weight (LD50 is the dose required to kill half the members of a tested population after a specified test duration) whereas cattle and poultry can tolerate more than ten times this dose without issue.

Depending on dose and individual susceptibility, death can occur in less than 24 hours.

10kg of this feed fed over a short period of time would be enough to kill a horse. With smaller doses the horse may survive but will suffer permanent damage to the heart and skeletal muscles.

Horses surviving the acute intoxication and those with chronic intoxication may exhibit signs of progressive congestive heart failure and muscle wasting. The damage to cardiac muscle is irreparable.

Horses surviving intoxication have a guarded prognosis for long-term survival and return to fitness.

Sudden deaths in the weeks or even months following intoxication have been reported.

Treatment of monensin poisoning is primarily supportive – there is no antidote.

SOURCE: http://www.fda.gov/Safety/Recalls/ucm421466.htm