As a homesteader, you’re no doubt aware that there’s a long list of plants you should keep your goats away from. Are tomato plants on that list? While there’s no controversy over goats eating actual tomato fruits, there’s a surprising amount of misinformation surrounding goats eating the leaves and stems from tomato vines.
So can goats eat tomato plants?
Quick answer : Yes they can. And there’s actual science behind that claim.
My own goats have occasionally eaten tomato plants and they’re still hale and hearty. Other goat owners have similar stories.
The rest of this post will focus on the available research which shows that tomato plants are safe for goats to eat.
Where Does the Confusion About Goats Eating Tomato Plants Come From?
Tomatoes belong to the nightshade family of plants – or to give the family its botanical name, the Solanaceae family.
Various plants in this family give us some of our favorite vegetables – potatoes, peppers, eggplant, and of course tomatoes.
Other Solanaceae members like Atropa belladonna (deadly nightsade), are highly toxic.
The toxicity of nightshades is due to certain alkaloids that the plants produce as a defense mechanism against bacteria, parasites, and grazing animals.
Not all of the alkaloids are toxic, and some even have beneficial pharmacological properties.
The alkaloids we need to know about to determine whether goats can eat tomato plants safely, are two glycoalkaloids called tomatine and solanine.
Solanine is a toxin, but it isn’t present in any large amounts in tomato plants. Solanine is the problematic alkaloid found in green potatoes and potato plants.
Tomatine Not Solanine Is The Tomato Plant Glycoalkaloid
The main glycoalkaloid present in tomatoes and tomato plants is tomatine. Tomatine is also called lycopersicin, and far from being toxic, it actually has some health benefits.
While researching a culinary article about tomato leaves for the New York Times back in 2009, food science writer, Harold McGee, scoured medical and veterinary literature looking for evidence of their toxicity.
Having found little convincing evidence, he contacted a researcher at the Department of Agriculture to find out if the leaves of the tomato plant were safe to consume.
Dr. Mendel Friedman, a scientist with a long background in tomato and potato alkaloid research, explained that the tomato glycoalkaloid tomatine, passes through the digestive system of animals largely unabsorbed, and that it had caused no problems in the lab animals used for their experiments.
His research had also found that tomatine was able to lower LDL cholesterol in animals.
During the digestive process, tomatine appears to bind to cholesterol. Then both the tomatine and the cholesterol are excreted from the body.
Cornell University Says Tomato Plants Are Safe For Livestock
The Cornell University College of Agriculture and Life Sciences maintains a database of Plants Poisonous to Livestock.
The first thing to note here, is that while the nightshades Belladonna and Potato both appear on the list of poisonous plants. The tomato and the tomato plant are both absent.
Next, we can go to their entry on steroid alkaloids which is mainly concerned with the type of glycoalkaloid found in potatoes, where they state that
glycoalkaloids are poorly absorbed by the gastrointestinal tract of mammals, […] these metabolites are rapidly excreted in the urine and feces of mammals. Because exposure to these poisons is generally by ingestion, it takes a relatively large amount of them to cause death.Cornell University College of Agriculture and Life Sciences
As we’ve already learned from Dr Mendel Friedman, the glycoalkaloids in potatoes and tomatoes are not the same, and tomatine passes through the digestive system of mammals without causing any harm.
And here, from Cornell, we have another confirmation that these alkaloids not absorbed in any great amount.
What Did Studies In Israel & Egypt Using Tomato Vines As Feed For Livestock Find?
Now let’s turn to feeding trials carried out by researchers in Israel and Egypt.
The trial in Israel lasted for 42 days and looked at the effects of feeding cattle dried tomato vines instead of hay.
The cattle in the trial suffered no adverse effects, there were no negative outcomes for body weight, and there were no differences in blood tests results between the group fed dried tomato vine and the group fed hay.
The amount of crop residue from global tomato production is huge, estimated to be between 10 and 25 millions tons a year.
Making this protein and mineral rich crop residue available as fodder would be a good use for it. But the widespread use of pesticides in most commercial tomato cultivation is a concern, particularly for dairy animals.
Nevertheless, tomato vines have been used as feed for sheep and dairy cows in Costa Rica.
In Egypt, a study using various forms (dried, fresh, silage, added bacteria, etc.) of tomato stems and leaves as a dairy cattle feed for 28 days, found that some forms of the tomato plants increased milk production with no other adverse effects. However the consumption of fresh tomato vines produced elevated levels of blood glucose, cholesterol, globulin, urea, creatinin, and AST & ALT liver enzymes.
The researchers attribute these raised levels to pesticide residue, which was higher on the fresh tomato vines than the dried or silage form of the vines. They report as follows:
However, the changes in carbohydrate metabolism induced by pesticides can be correlated with the effects of these chemicals on the activities of hepatic enzyme system which are intimately involved in glucose production, storage and metabolism and/or correlated with the endocrine activity of the pancreas (insulin activity).STUDY ON THE USE OF TOMATO VINES IN RUMINANT FEEDING – PDF DOWNLOAD
What can we learn from this research?
Large amounts of dried or otherwise treated tomato vines fed to livestock have not produced any toxic effects. Long term consumption of fresh tomato vines had an effect on blood chemistry, but this appears to be related to the action of the pesticide residue on the fresh vines rather than any constituent of the tomato plant itself.
One thing that the studies don’t mention is the effect of this type of feed material on droppings. An answer to a question asked on the Cornell website contains this remark, ” I know of vegetable/sheep operations in California that routinely fed the tomato vines to sheep and just accepted the diarrhea along with this forage, to get rid of the vines and to feed the sheep cheaply.”
Would the small amount of tomato plant material available to an average homesteader have the same effect on goats as it does on sheep routinely fed the crop waste? And what’s the impact of pesticide residue (if any) on this aspect? These are questions I don’t have an answer to.
Can Goats Eat Tomato Plants – What’s The Takeaway For Homesteaders?
We know that the common concern over the glycoalkaloid content in tomato plants in unfounded.
Firstly, because the toxic effect of solanine is a concern for potatoes, not tomatoes.
And secondly, because researchers have stated that tomatine, the tomato glycoalkaloid, is not absorbed into the body during digestion.
Feeding trials have shown no toxic outcomes for livestock fed on tomato plant crop waste. And the changes in blood chemistry that were observed from the long term feeding of fresh tomato foliage were attributed to the effects of pesticide residue.
As a homesteader, if you’re using pesticides on your tomato plants (or any plants), you should probably avoid feeding crop waste to your goats. But I don’t see any cause for concern if your goats only nipped at a few leaves when they broke into your garden area.
If you don’t use any pesticides, then there doesn’t appear to be any cause for concern, other than a possibility of diarrhea, when it comes to letting your goats eat tomato plants.
Personally, by the time I get around to clearing away the tomato plants from my garden and polytunnel, they look in such a degraded state that the only place they’re fit for is the compost heap. If I made an effort to deal with them sooner, so I could feed them to my goats, I would throw a couple of plants into their field each day without any concerns.
I hope this post has given you some useful information, and has set your mind at ease if your goats got loose and attacked your tomato plants.
And if you were wondering if your goats can eat dead tomato plants, the studies referenced above should help you to make an informed decision.
And now for an obligatory disclaimer: I’m not a vet, or an agricultural scientist, or an expert of any kind. I’m a regular homesteader, just like my readers, and I base my opinions on the research I’ve been able to find, along with my own experience. Please do your own research and come to your own conclusions.
Thanks for reading: Can Goats Eat Tomato Plants – What Does Research Show?