I was lucky enough to spend a few days in Louisiana the end of September where I talked about how to teach livestock to eat weeds, and I got to teach folks to eat cricket brownies and fried larvae. It was a GREAT trip thanks to my host, Alan DeRamus. But perhaps the highlight was my visit with Don and Betty Ashford who used my training process to teach their cows to eat weeds. Not only did their herd learn to eat chamberbitter weed/Mimosa weed (phyllanthus urinaria), they also decided all on their own to eat teaweed (Sida spinosa) and huge mouthfuls of horsenettle (Solanum carolinense). I was so tickled about them eating horsenettle that I jumped up and down, giggled a lot, and hugged everyone in the vicinity.
I’ve been looking at horsenettle over and over again for a long time because lots of people ask me if cows can eat it. Here’s what I started to tell everyone:
“The primary toxin in horse nettle is solanine. I haven’t found anything that specifically says that this plant causes poisonings. All my resources simply say that it is part of a genus that has been associated with toxic effects. The primary problem is irritation of the digestive tract. But it appears that results can be erratic. Here’s a quote from Toxic Plants of North America: ” There has been particular concern about the toxicity potential of the speicies of Solanum commonly called nightshades, but the hazard with the various species is quite erratic, and evidence is conflicting as to the actual overall risk. In some instances, investigators have been unable to produce intoxications…and in other cases digestive disturbances have been reported.” What the editors of the book seem most concerned about is actually potatoes.
“If it were me, I’d go ahead and train cattle to eat it, but I’d be sure that they have plenty of variety available. I would watch for evidence of digestive tract upset, and if they suddenly seemed “depressed” I’d give them some activated charcoal as that is supposed to help with any negative effects. I really don’t think that would be necessary, but I’ve done a couple of plants (Leafy spurge) for example, that I’ve been prepared for, even though nothing happened.”
That being said, horsenettle did make me a little nervous. Because I’ve spent so much time watching and teaching cows, it’s a plant that I’d want to be on site to work with the farmer/rancher on teaching. That way I could pay attention to the animals and know if they were having difficulties. But that isn’t always possible. So in the case of a plant that makes me nervous, I always suggest teaching something else instead. My experience is that the teaching process opens animals’ minds to the idea that food could come in all kinds of shapes, sizes, and flavors, so they begin trying lots of things in pasture, and will probably try the plant that makes me a little hesitant. For example, I followed one herd for 6 years and found that they were eating all kinds of things in pasture including things I thought they probably shouldn’t. But there were no harmful effects.
When I think through all the research that is out there, it makes sense. First, the dose is what causes problems, and animals eating a wide variety of forages are unlikely to eat enough of the questionable plant to be poisoned. Second, research has demonstrated that some toxins and some nutrients offset the effects of other toxins. The problem is that it will take us decades to untangle all the possible relationships. Meanwhile, I know that animals choose foods based on the feedback they get from them. That means that I don’t have to know all the answers. I can just rely on the cow’s feedback mechanism to do the job.
When I started working with Don Ashford in Louisiana he had three weeds he was interested in: teaweed, chamberbitter weed, and horsenettle. He told me that he had heifers who had eaten the berries of horsenettle with no problem. About the same time I got a note from a reader who said that her herd of sheep had spent almost a week eating horse nettle berries with no negative effects. But I was still on the fence. So we settled on teaching the cattle to eat chamberbitter weed first. I figured that if they were successful with chamberbitter weed, they’d go on and try the others in pasture on their own. Sure enough, that’s what happened. And they ate BIG mouthfuls of the horse nettle.
I’d say the success is due in part to the kinds of pastures Don has. There’s plenty of grass, but there’s plenty of chamberbitterweed, teaweed, and assorted other forbs as well. All that makes for a smorgasbord that allows cows to be very successful when using their internal feedback to decide what to eat.
Should you teach your cows to eat horsenettle? You could, but I would probably go the same route that I went with Don. It’s so easy, and you run no risks at all.