BENTONVILLE, Ark. - It had the makings of a pleasant fall day when Sonny strolled into the office, humming a tune to match his opinion of the day.

"What's got you so lively this morning?" I asked.

Breaking into a big smile, he replied, "On top of the fine weather, someone fed my cows this morning and I don't even know who to thank!"

My curiosity piqued; I asked for details and Sonny obliged.

"Well, I'm pasturing a group of cows in a field just off the county road," he said. "When I stopped to check them this morning, someone had already tossed a whole truckload of haygrazer over the fence.

"The cows were really liking it too since that field was getting pretty short," Sonny said.

My next question only served to cloud Sonny's day.

"Do you suppose someone was using your cows to check the toxicity of the haygrazer before feeding it to their own?"

Sonny's smile turned to a frown just before reaching a full-blown state of mad as the idea settled in that anyone would do such a thing.

Haygrazer, sudan, johnsongrass and related plants can be some of the best forage on any farm of any size, but each is tied to two potential toxins. Nitrate toxicity, a factor of nitrogen fertilization level, has eased due to higher prices and animal manure regulations. The second toxin, prussic acid or cyanide, is comparable to a lazy brother-in-law since you never know when he might show up.

As dairy farms diminish, so have the acres of sorghum-related forages. However, johnsongrass continues to fill road right-of-ways and fence rows, serving as a seed bank to contaminate forage acreage. Nutritionally, johnsongrass can be superior forage, but weather patterns (hot, dry, cloudy, or cold) may cause a buildup of cyanide in the plant throughout the growing season.

Unlike nitrates, it is impossible to check cyanide levels, leaving producers to question the safety of certain fields. Hay is not a problem since the toxin turns to gas and dissipates after plants cure. That logic is often implemented in pastures, where patches of johnsongrass are clipped and allowed to cure a few days before turning cattle in to graze.

Another confounding point is that some producers report johnsongrass in every pasture and never experience problems. Experienced veterinarians subscribe to the theory that cattle must develop tolerance to johnsongrass toxins while grazing it during the April - October growing season. However, place a new animal in that group and you could easily find it dead within the hour.

Although Sonny didn't lose any cows, he did lose a little faith in his fellow man. ‘Til next week!

Source: Robert Seay, Benton County Extension Agent Staff Chair, University of Arkansas Extension