Animal Health Matters: Rusty oats and information sources

Russ Daly
Special to the Farm Forum

It seems like I’ve led off most of my columns this year with some sort of statement about the weather. Blizzards from January through April, a wet cool spring, the recent rains and flooding – they’ve affected us all in some way or another, including the animals we care for.

So here I go again. The abnormally wet and cool spring and early summer threw big obstacles in the way of farmers and their planting plans. It wasn’t uncommon to hear from producers unable to plant half or more of their ground.

When corn or soybeans became out of the question for most of these fields, cover crops entered the picture. In fields that eventually dried, crops like peas, radishes, grasses, and small grains were able to be planted. This was much better than letting the farmground sit idle, providing for healthier soil and a better foundation for next year’s crops. Additionally, some of these cover crops could be utilized for hay or for grazing livestock.

One of those popular cover crops, oats, has been the source of a lot of questions this fall. Unfortunately, the cool wet weather that screwed up farmers’ planting intentions also fostered a disease problem for oats – crown rust.

My response to animal disease questions is usually, “I got this,” while my response to crop disease questions is usually, “Crops get diseases?” Crown rust in oats is something I have vast experience with, though. We raised a lot of oats on our farm in the days before rust-resistant varieties were developed. It wasn’t uncommon for me to return home from windrowing (in a no-cab IH windrower) coated in an orange film of rust from the oats.

That rust – yellow-orange spots on the leaves of the oat plant – was bad for crop productivity but it didn’t affect the cattle we fed the oat hay or oatlage to. The question of whether cattle could be harmed from rusty oats has been a pretty common one lately.

When molds like crown rust affect forage or feed crops, there are two considerations. One is their potential to produce toxic by-products; an example would be aflatoxin produced by the Aspergillus mold in corn. Crown rust doesn’t do this – any substances it produces aren’t considered toxic to livestock. The other consideration is the millions of mold spores thrown into the air when the crop is fed as hay (or windrowed by a teenager). These are mostly harmless, but some animals, particularly horses, can be sensitive to these spores, resulting in an allergic asthma type of situation. This happens only in certain individual animals, and isn’t a phenomenon limited to rusty oats.

As I took the calls about the livestock safety of rusty oats this month, it became apparent to me that many livestock producers didn’t get the message about their relative harmlessness. Many assumed the worst without doing much homework. I heard of producers destroying their rusty oats instead of feeding it to their livestock. Maybe this was a strategy some were going to employ anyway (they’d already gotten the soil benefits), but it occurred to me that some livestock feeding opportunities had been lost.

The rusty oats issue probably doesn’t affect very many producers. But it made me think about the larger issues of where and how we get our information. The people who contacted me or others in Extension got the correct answers. What about those who heard that rusty oats would kill their cattle? Where did they get their facts from? If the answer doesn’t come to the top on a Google search, do they just give up and assume the worst? Do they get their information from a trusted neighbor or friend who may mean well but isn’t as well-informed as they should be?

It’s those questions about information sources – just as much as the “scientsy” ones – that inspire my work, and the work of others in Extension. We work hard to bring unbiased, evidence-based answers to the technical questions while dealing with the challenges of getting heard. The next time you have a question about the effects of something unusual on your animals or crops, check SDSU’s Extension website, or give us a call.