June 2, 2017

Nutrena has released an updated statement regarding two horse deaths in California.

The company says it is “confident that the unfortunate deaths of these two horses was not caused by monensin contamination in our feed [sic].” The statement is the result of an inspection conducted by the State of California Department of Food and Agriculture (CDFA), in addition to the testing of multiple feed samples and gut contents.

Nutrena states testing of reserve feed and the gut contents did not contain monensin. We have requested the feed types, lot numbers, and documentation from the company and CDFA.

We have been unable to verify the current status of the CDFA investigation through the state.

Nutrena states it takes the “obligation to provide safe and quality feed very seriously”.

Stay with us as we bring you more information as it becomes available.


SafeChoice Senior Horse Feed

Lab results detected two ionophores in a bag of Nutrena horse feed after two horses died last month. The horses’ SafeChoice Senior horse feed tested positive for monensin and showed trace amounts of lasalocid.

California officials tested the feed after two horses at La Tuna Stables in Sun Valley, CA died three days apart. Kristina Boyd split the same bag of SafeChoice Senior, lot #8470746581, between the horses.

Lab results detected two ionophores in a bag of Nutrena horse feed after two horses died last month. The horses' SafeChoice Senior horse feed tested positive for monensin and showed trace amounts of lasalocid.

No expert or regulatory body has opined how the horse feed may have become contaminated.

Boyd’s 18-year-old Hanoverian gelding dropped dead in his stall on April 25. Two days prior, Boyd says Mickey didn’t seem like himself. “He was sluggish, he didn’t want to trot, so I put him back in the pasture.”

Boyd says she initially thought Mickey suffered a heart attack. That is, until his stablemate that shared the same bag of Nutrena feed, died suddenly. After Tango died, Boyd called her veterinarian, who reportedly told her about monensin, which led to the state’s testing of the feed.

“I had never heard the word monensin,” Boyd adds. She says if she had known a “toxic ingredient” meant for cattle was milled at the same place as her equine feed she would not have purchased it.

UC Davis California Animal Health and Food Safety is testing additional feed samples, limited tissue samples from the second horse and its gut contents.

Cattle and poultry producers use the antibacterial agents monensin and lasalocid to promote more efficient growth.

Both ionophores are highly poisonous to horses. The level of toxicity is dose and individual dependent. Symptoms may include colic, sweating, muscle wasting, nosebleed, fatigue, bloating, kidney failure, heart damage, respiratory distress, and the inability to stand.

There is no antidote for monensin poisoning.

Nutrena investigates

“The test results were a surprise to us along with the horses’ symptoms,” Roy Johnson, a Cargill Equine Feed Expert tells Rate My Horse PRO. He adds the company is conducting its own “thorough investigation”.

Nutrena obtained samples of hay, forage, and water from La Tuna Stables for testing. “Our goal is to find out what happened to [the] horses. If it’s our problem, we own it,” Johnson adds.

While it is not certain that the two deaths are related, it does not appear that the deaths were the result of monensin poisoning, Nutrena said in a public statement. The company also promised transparency throughout the process.

Nutrena manufactured the dry pelleted senior horse feed at its Stockton, CA plant. Tim Loesch, Communications Director for Cargill Animal Nutrition tells us the location “does have monensin onsite but uses a monensin-free packing line for our equine feeds”. It also manufactures feed for poultry, swine, and dairy cattle, but only in bulk for the latter, Loesch notes.

Although Nutrena claims the majority of its manufacturing mills are monensin-free, Loesch wouldn’t share how many are also milling medicated feeds for other species, citing Cargill’s “confidential production practices”.

Cargill Feed and Nutrition has 44 feed mills in the U.S., which 22 of the plants produce retail horse feed. Loesch says there is no connection between “the medicated feed license status and whether they have monensin on site.”

Cross contamination of equine feed

The toxicology report from UC Davis detected lasalocid in “trace concentrations” from the initial feed sample.

Monensin was detected above the reporting limit of .1 ppm (parts per million) but the actual concentration is estimated to be below 1 ppm, the report adds. “Below the 1 ppm, the estimation is not accurate, though considered positive. Concentrations of 1 ppm are common in commercial feeds due to carryover issues in the processing plants.”

The FDA maintains there is no acceptable amount of monensin allowed in equine feed since it is not approved.

On the farm, contamination may pose a risk for horses living with cattle or other ruminants that eat medicated feed.

Two goats and two mini-alpacas are residents at La Tuna Stables, which offers horse boarding near Burbank. Boyd says the alpacas eat timothy hay but she isn’t sure what the goats eat since their owner feeds them. “The goat feed is in a separate room away from the horses’ feed,” Boyd adds.

Cross-contamination in the milling process of equine feed, due to human error or mechanical failure, can expose horses to varying amounts of monensin.

Nutrena states it implements strict safety measures at its facilities manufacturing horse feeds that aren’t monensin-free. The company adds the facilities mitigate the risk of contamination by following FDA-approved Good Manufacturing Practices.

Boyd says after the test results came back on Thursday, May 11, her conversation days later with Johnson, Cargill’s Equine Feed Expert was “a bit disappointing”. “We have two horses dead and monensin shouldn’t be there. He just wanted to tell stories. It didn’t seem like he wanted to take any responsibility.”

Boyd continues, “it is very suspicious. There should be no monensin in horse feed, no matter how small the amount.”

No expert or regulatory body has opined how the horse feed may have become contaminated.

Nutrena has not issued a product recall. Read the company’s full statement here.

Stay with us as we continue to provide updates as confirmed information becomes available.


Disclosure: Cargill’s brand Nutrena has sponsored Rate My Horse PRO since 2013.

Update: Nutrena ended its business relationship with Rate My Horse PRO in June 2017. As a reputable and trusted source of horse news, our business relationships have no bearing on our news reporting.