Can Cows Eat Tomato Plants?

By Erin Marissa Russell

Do you need to know whether cows can eat tomato plants? We’ve got everything you need to know about tomato plants and cows right here.

Cows can eat ripe red tomatoes, but other parts of the tomato plant, along with unripe green tomatoes, are toxic to cows. Even the occasional green portion of a ripe red tomato contains poison and should not be fed to cows. Cooking green tomatoes does not decrease their toxicity to cows.

The poison that makes the tomato plants and green tomato fruits toxic is an alkaloid similar to solanine, called tomatine or saponin. It is a natural poison from the steroidal glycoalkaloid group. Other members of the nightshade family (the plant family to which tomatoes belong) also contain this alkaloid in their foliage, tubers, and green fruit. These include potato, eggplant, and bell pepper.

The tomato plant’s unpleasant smell is a natural defense system on the plant’s part to keep animals from eating it. The green portions of the tomato fruit lose their toxicity as they ripen. Once the fruit is red, it no longer contains poison and is safe to consume. (Of course, some varieties of tomatoes ripen to yellow or orange instead of red. Once they have ripened, these are as safe for cows to consume as red tomatoes.)

Ripe tomatoes are a nutritious food source for cows. They contain lots of fiber, vitamins, and minerals that make them a great addition to the cows’ diet. Tomatoes are comparable in protein and energy content to high quality hay.

You can feed ripe tomatoes to cows as up to 15 percent of a concentrate ration. A weekly total of three or four tomatoes, spread out over two or three feeding sessions per week, is plenty for cows and they should not be fed more. Because of their water content, too many tomatoes can soften the stool of cows. Make sure that tomatoes you feed to cows are fresh and not spoiled or moldy. Consumption of spoiled or moldy tomatoes can cause illness in cows.

To sum up, while you can feed ripe red tomatoes to your cows, the animals should not be allowed to feed on the tomatoes from the plants on their own. Parts of the tomato plant other than the ripe fruits should not be consumed, as the rest of the plant is toxic for cows. Any green portions of the ripe tomatoes should be cut out and discarded before ripe tomatoes are fed to the cows.

Consumption of the tomato plant or unripe tomato fruits can cause symptoms in cows like diarrhea, intestinal irritation, lethargy, or vomiting. If your cow ingests tomato plants or unripe tomato fruit, contact your veterinarian.