Researchers at Utah State University have conducted several studies that show that tannins in forages can reduce parasite loads in livestock, and that animals will choose to eat more foods with tannins when they are infested with parasites. Most shrubs contain tannins, and tannins can also be found in sudangrass, birdsfoot and big trefoil, sorghum, sulla, sainfoin and sericea lespedeza. This means that we can reduce our parasite problems by simply adding these forages to our pastures, and helping our livestock to learn to eat them. It’s also possible that we could provide our livestock with supplements that contain tannins to reduce parasite loads.
In trials, researchers worked with sheep because their smaller size made feeding and managing the animals easier. Dr. Juan Villalba and graduate student Larry Lisonbee, fed penned lambs a supplement that contained tannins. In the first of their two studies, they found that lambs with lots of parasites ate more of the supplement than lambs without parasites. Then, as the parasite numbers declined in the lambs, they ate less and less of the tannin containing supplement. In a second study, they actually measured the fecal egg counts in the lambs infested with parasites. Again, they found that infested animals ate more of the tannin containing supplement. They also found a direct correlation between the amount of tannin eat and the decline in fecal egg counts.
What does this tell us?
First, animals can tell when they have parasite infestations. We know this because when the lambs had high parasite loads, they ate lots of tannin containing food, and then ate less as the number of parasites they had declined. Second, animals can learn to eat a food that helps them solve their parasite problems. Finally, we know that tannins can reduce parasite loads.
Introducing Tannin Foods To Your Animals
When Juan and Larry began their trials, at first the lambs weren’t interested in eating the alfalfa with the tannin supplement regardless of their parasite load. So they decided to familiarize the animals with the tannin containing food before continuing with the trial. They gave the lambs the supplement every day for two hours for five days total. This made the supplement familiar to the lambs and they began to eat it. Then those with higher parasite loads began eating a lot of it. Exposing your animals to a supplement over a period of days is a good way to get them used to the idea of eating it.
When it comes to forages, this solution may not work quite as well. In that case, consider teaching your livestock to eat a new forage using Kathy’s technique for training animals to eat weeds. It’s short and sweet, and opens minds of livestock to the idea that there is a lot more in the pasture to eat than they may originally have thought. Here’s a link to an article for more information.