Humans have fed seaweed to domesticated animals for a very long time, perhaps even longer than recorded history. Although people may have first used beach-cast kelp as cattle or sheep forage to save money or to get through scarce times with a free resource, those with keen observational skills saw that their animal’s health and vitality improved with seaweed rations. Much like humans in that respect! Today, we find many examples of animal rations containing seaweed, including ones for the four-legged companions we share our homes with. But, is it actually good for pets? And, is it OK to feed them human food-grade sea vegetables? The short answer is yes and yes, with some caveats. Read on to learn more about the history and science of seaweed for domesticated animals, and how to use it for pets.
History and science of seaweed for domesticated animals
People probably ate seaweed long before they domesticated animals. Dogs are thought to be the first domesticated wild animal, probably about 15,000 years ago. Sheep and goats were domesticated starting about 12,000 years ago, cats about 10,000 years ago, and chickens and cattle about 8,000 years ago. These animals all thrive when they eat seaweed and it’s been used in animal rations since the dawn of recorded writing. Cattle especially, perhaps because they are ruminants accustomed to forage, have often been fed seaweed rations. The Bellum Africanum, written in 45 BC, records that in times of scarcity Greeks collected seaweed from the shore and fed it to their cattle, and “thus prolonged their lives.” European coastal residents also used seaweed as sheep fodder, especially dulse. Sheep that naturally graze along the shore have been observed to prefer dulse and Alaria over other species such as rockweed or sugar kelp. Horses, on the other hand, are reported to prefer sugar kelp when given a choice.
However, mammals can’t survive long on seaweed alone and the science supporting it as a nutritious animal feed additive wasn’t very strong through much of the twentieth century. This was probably because scientists mostly focused on proximate analysis and energy availability studies, both of which failed to capture seaweed’s true benefits. It wasn’t until the 1970’s that researchers discovered that chelated minerals, such as those found in seaweed, more efficiently delivered micro-elements than the conventional inorganic minerals typically used in animal feeds (Evans and Critchley, 2014). In the early 2000’s, it also became understood that the complex polysaccharides found in seaweeds exerted prebiotic actions in the gut. Prebiotics are food and energy sources for probiotic bacteria, which benefit human and animal health in myriad fashions. This discovery is the basis for how certain seaweed species, particularly Asparagopsis taxiformis, can reduce methane production from cows and thus potentially lower their climate impact. Scientists also learned in the early 2000’s that the bioactive constituents abundant in seaweed, such as phlorotannins and antioxidants, had potentially powerful health benefits. This topic remains an area of intense study.
Friends and customers tell us that rockweed powder (sometimes known as kelp powder) improves their dog's sensitive skin and reduces hot spots. Kelp is especially beneficial for egg laying hens and ducks. A certain seaweed harvester we know trades their seaweed for duck eggs with exceptionally rich yolks. Take note, those of you with backyard flocks! Kelp can enhance pigments such as β-carotene, violaxanthin and fucoxanthin, resulting in richer colored and more nutritious yolks. Interestingly, feeding hens the brown seaweed Sargassum dentifolium at levels of 3% to 6% total feed ration lowered the level of cholesterol in their eggs. Besides improving egg quality, seaweed contains prebiotics that encourage a robust and diverse population of gut microbes, making it harder for avian and human pathogens such as Salmonella and Clostridium to gain purchase.
Chickens & ducks that get kelp in their diet lay richer eggs, like those seen on the left.
The most studied seaweed for animal feed has been rockweed, Ascophyllum nodosum. Rockweed has long been an animal forage feed, probably because it grows abundantly in the intertidal zone and is easy to gather at low tide. The Canadian company Acadian Seaplants started manufacturing Tasco® from wild harvested sundried rockweed about 30 years ago as an animal feed prebiotic. The company is happy to contribute their product to research studies, most of which affirm its benefit in animal nutrition. Acadian Seaplants has since become a good learning resource regarding seaweed for pets and other animals.
Another highly regarded company specializing in rockweed for animals is Source micronutrients, established in Maine in 1975. The story of Source’s founding says much about the benefits of seaweed for animals. In the late 1960’s, company founder Susan Domizi was competing on her eventing horse, Hull, with dreams of being on the US Equestrian Olympic Team. The horse had hoof problems that went unresolved despite top-notch veterinary care and a scientific diet. In search of solutions, Domizi learned of the nutritional power of seaweed and eventually developed a finely ground blend that she included in her horse’s feed. By 1969 Hull was named U.S. Intermediate Horse of the Year in Combined Training. Word of his improved health spread fast through the equestrian community and Domizi was soon in business. Today, Source continues to cater to horses but also has a Source Plus! blend specially designed for dogs. Maine Coast Sea Vegetables is pleased to offer this product in our web store.
Several pet food companies include seaweed in their formulations. Evermore Pet Food crafts nutritionally complete, premium diets for dogs and cats that include organic kelp sourced from Maine. Centinela Feed and Pet Supplies makes a special broth treat for dogs in a convenient pouch containing lamb, mackerel, and Maine kelp. Seaweed is said to be good for improving dental health and fighting bad breath in dogs. Animal Essentials sells Sea-Dent Anti-Plaque Powder for dogs, while NaturVet sells kelp-containing chewies and supplements for both dog and cat health.
Birds and fish also like a little seaweed in their diet. TOP’s Parrot Food includes organic dulse and kelp to add iodine and minerals to their avian diets. Hash Fish Foods specializes in high-quality, nutritious fish food for herbivore fish such as tangs, rabbit fish, and various bottom dwelling fish. Their formulation includes laver, dulse, sea lettuce, and Irish moss, all sourced from the North Atlantic.
Can pets eat the same seaweed you do?
Clearly, pets can eat seaweed and it’s good for them, but can they eat the same sea vegetables you do? Maybe you bought more than you can eat, have some past its shelf-life date, or just want to share the wealth with your furry companion. Or maybe you discovered that your pet got into your seaweed stash and you’re not sure if that’s safe. This situation actually occurred when MCSV founder Shep Erhart’s cat Lily developed a love of laver! Lily would go so far as to claw open the cabinet and tear into a bag. Whatever the motivation, your pets can certainly benefit when you share your sea vegetables, so long as you follow some common-sense recommendations.
The first thing to note is that rockweed isn’t the only species pets can eat. All seaweeds contain a healthful blend of chelated microminerals, iodine, prebiotic polysaccharides, and beneficial bioactive compounds. Their composition and levels vary and it’s hard to say that any one species is “best” for pets. However, their flavors surely differ, and just like with humans, pets may prefer some kinds over others. Just don’t be hurt if they don’t like the same seaweed you do! You may have to experiment with different kinds to find one your pet likes.
The second thing to note is that a little bit goes a long way. It’s super important to keep this in mind. In particular, high iodine sugar kelp should be used sparingly and it should not be fed to cats, which are iodine sensitive. But, even species with lower iodine content such as Alaria or dulse should be used in small amounts. Unless you’re a very small person or live with a very large dog like an Irish wolfhound or Saint Bernard, by and large our pets are much smaller than we are. That means you should scale the recommended serving size for a human to the smaller size of your pet. For instance, if you have some organic powdered dulse in your larder, which has a recommended serving size of 1 tsp (about 4g), than a 75lb dog should get about half that amount (1/2 tsp), a 35lb dog about one quarter that amount (1/4 tsp), and just a pinch for a cat. Whatever you do, never just dump a pile of seaweed in your dog’s bowl. They may gobble it down (though most dogs probably wouldn’t), but it’s virtually guaranteed to come back up, and it wouldn’t be good if it did not. Too much seaweed can make dogs and other pets quite ill.
Speaking of seaweed powder, this is probably the easiest and best form for feeding to pets, although flakes and granules are OK too. If you want to feed them leaf, it’s best to grind it into a finer form first. Not only does this make measuring it out more reliable, it also helps you disperse the seaweed throughout your pets’ kibble.
Finally, it’s probably best to include seaweed in your pets’ diet just a few times per week, especially when first starting out. It’s not an exact science, but one meal per day every other day seems reasonable. Keep a close eye on them for the first several weeks. Do their eyes seem more alert and sparkling? Do they have new pep in their step? Does their coat look more lustrous? Perhaps with less dander? Did your pooch's hot spots go away? If the answer is yes to any or all of these, then seaweed is working its magic.
On the other hand, if they throw up shortly after eating seaweed infused kibble, you’re either giving them too much, it’s the wrong species for their physiology, or their physiology won’t tolerate any kind of seaweed. Try reducing the amount and/or using a different species before giving up. Sometimes it just takes a little time for their stomachs to adapt. However, ultimately you may have to accept that your pet simply doesn’t tolerate seaweed. They may just take one sniff and walk away. That’s OK, though. Sea vegetables may not work for everyone, but when they do, this potent superfood can work wonders!