Wait, which animals raise livestock?
Several species of ants will 'herd' aphids around (a type of plant lice)- even picking them up and putting them back with the group if they wander off. The ants will attack anything that approaches their aphid herds, defending them. The aphids produce a sugary excretion called honeydew, which the ants harvest and eat.
Some ants will even 'milk' the aphids, stroking the aphids with their antennae, to stimulate them to release honeydew. Some aphids have become 'domesticated' by the ants, and depend entirely on their caretaker ants to milk them.
When the host plant is depleted of resources and dies, the ants will pick up their herd of aphids and carry them to a new plant to feed on - a new 'pasture' if you will.
Some ants continue to care for aphids overwinter, when otherwise they'd die. The ants carry aphid eggs into their own nests, and will even go out of their way to destroy the eggs of aphid-predators, like ladybugs.
--
Microhylids – or narrow-mouthed frogs - have an interesting symbiosis with Tarantulas.
While the spiders could very easily kill and eat the much-tinier frogs, and DO normally prey on small frogs, young spiders instead will use their mouthparts to pick up the microhylid frogs, bring them back to their burrow, and release them unharmed.
The frog benefits from hanging out in/around the burrow of the tarantula, because the tarantula can scare away or eat predators that normally prey on tiny frogs, like snakes, geckos, and mantids. The tarantula gets a babysitter.
Microhylid frogs specialize in eating ants, and ants are one of the major predators of spider eggs. By eating ants, the frogs protect the spider's eggs. The frogs can also lay their eggs in the burrow, and won't be eaten by the spider.
So it's less 'livestock' and more like a housepet - a dog or a cat. You stop coyotes/eagles from hurting your little dog/cat, and in return the dog/cat keeps rats away from your baby.
--
Damselfish grow algae on rocks and corals. They defend these gardens ferociously, and will attack anything that comes too close - even humans. They spend much of their time weeding the gardens, removing unwanted algaes that might overtake their crop.
The species of algae that they cultivate is weak and and sensitive to growing conditions, and can easily be overgrazed by other herbivores. That particular algae tends to grow poorly in areas where damselfish aren't around to protect and farm it.
Damselfish will ALSO actively protect Mysidium integrum (little shrimp-like crustacians) in their reef farms, despite eating other similarly sized invertebrates. The mysids are filter feeders, who feed on zooplankton and free-floating algae, and their waste fertilizes the algae farms. Many types of zooplankton can feed on the algae crop, and the mysids prevent that.
While Mysids can be found around the world, the only place you'll find swarms of Musidium integrum is on the algae farms that Damselfish cultivate.
Damselfish treat the little mysids like some homesteaders treat ducks. Ducks eat snails and other insect pests on our crops, and their poop fertilizes the land. The ducks can be eaten, but aren't often, since they're more useful for their services than their meat.
--
There are SEVERAL species of insect and animal which actively farm. They perform fungiculture and horticulture: deliberately growing and harvesting fungus and plants at a large-scale to feed their population.
Leaf-cutter ants and Termites both chew up plant material and then seed it with a specific type of fungus. The fungus grows, and the termites/ants harvest the mushroom as a food source.
Ambrosia beetles burrow into decaying trees, hollow out little farming rooms, and introduce a specific fungii (the ambrosia fungi), which both adults and larval beetles feed on.
Marsh Periwinkles (a type of snail) cultivates fungus on cordgrass. They wound the plant with their scraping tongue, then defecate into the wound so their preferred fungus will infect it and grow there. They let the fungus grow in the wound a bit, and come back later to eat.
