:: a wiki project
There are bunch of things to explore with this question.
One is, what is sentience and how sentient are animals? Trees and plants? With dena Yeresbeth changing humans, how have animals changed? Some have changed a great deal, and tend not to deal with humans at all, so humans have difficulty evaluating that change. The world from these creatures' POV is radically different: it's bounded by places you don't go because of Them--the humans, who tend to spread worse than ivy. covering everything with their touch, roots, etc.
For humans, the question of eating animals goes right back to the fraught early days on how to become civilized--how not to be summarily destroyed by the indigenous races. Because three impressions came through crystal clear: the indigenous races thought humans evil predators because they killed one another, they force-mated one another, and they ate other child-bearing beings.
The question of cannibalism has been hotly debated in mage circles: did it actually take place, or did the indigenous beings conflate all mammals as the same type of being? That question certainly was important early on, because the very first mages firmly set mammals (those who birthed and cared for their young) as outside the category of food. Also outside were those with wings, and again, here the reasoning is dicey because there may have been dragons in the world at that time, there is scarce, but definite evidence, and what did they eat? Anyway, food category included fowl who did not fly (turkeys, chicken, etc) and fish--but not mammalian fish, as big cetaceans, etc, made their wishes clear over time.
But the question of eating any animal has been debated down through the years. What if chickens become sentient? So far, no one has pointed to sentient chickens, and no chickens have exhibited any signs: if they did, would they run away? But then they become prey to the big carnivores, who do prey on one another, and can humans interfere with that? The animals in what humans call the wild seem to have their own rules, but they refuse to permit human interference.
A whole separate world is experienced by some animals who live in the human world and the wild. Cats and rats (and mice) are two examples. Dogs, to a lesser degree, as they have aligned with humans more closely over the centuries. Rats in some areas are considered part of the cycle of keeping the houses and cities clean. The question of rat droppings is solved by spell: it's far easier to establish a single spell over your home than many spells to ward various insects, etc. In such places, rats frequently have their limitation on birth lifted so they can have more than one litter. Then their population rises. The rats have adapted to eat what humans don't want around, and their leavings are zapped by wards, which makes humans happy, but when their population rises, the cats go to war.
No one has successfully bred the war instinct out of cats and rats. The cats simply vanish if the humans interfere too much with them. Cats are fascinating to many humans as they cross boundaries easily, they domesticate when they feel like it, but cat wars persist: against one another, against rats. (mice are at the bottom of the chain, and their defense is to hide. Because of the one littler spell, mice don't overrun anywhere. They are kept as pets in some places.)
Humans in various places keep the single-litter spell in place so the rat population stays down, in which case the feral cat population moves elsewhere. the Cats vs Rats war never impinges much on human life because the populations of cats and rats never rise above a certain level: if, somewhere, someone has done a local eradication spell on the universal ward limiting cat and rat reproduction and the resultant population swells and spreads, someone else re-establishes the spell, and the population gradually subsides.
In the wild, of course, the animals have their own summary methods of population control.
There are wild dogs, but mostly they've aligned themselves firmly with the humans. Questions of dog sentience have become fraught since DY made its reappearance, even among dogs. They and some of the sea creatures have found methods of communication that do not include talking, but their perception of being, communication, reality, history, etc are so different than human (just in the category of smell alone) that finding common ground for exchange of ideas is still in its rudimentary stages.
Relations are not all that startlingly different. Human/bee relations are largely the same, for example. Honey is a strong food staple, and bee-keeping has its guild, but there's no monumental difference as humans never ate bees. Relations with sea creatures were historically more fraught, but mammal/human relations were settled early on, and sea life and humans leave one another alone, except when humans are found in the sea, they are usually taken by the mers.
Human/horse relations get more story time, so there doesn't need to be much added here: in some places the communication is strong, like with dogs, others, life is separate but intersecting circles in the expected area of travel, etc.
Cows and oxen are for milk, cheese, beasts of travel and plough. Cows and oxen are peaceable creatures, who seem not to have found it necessary to venture into the angsty world of communication, etc. A day spent chewing grass is a good day: a day hauling a wagon with one's companion without too much interference from the humans is a good day.
This is actually a complex question, but outside of mages, few bother with it. After all, trees don't talk, and except for in certain circumstances, they don't move around. The Hervithe are tree guardians of indigenous species, but as the Wood Guild and the Mage Council are deadly strict about wood laws, the Hervithe have little to do with humans.
It is believed that Old Sartorans had a lot more communication with trees than present humans, and there was evidence in some taerans that turning human into tree for a stated time was the common method of social correction. Until after the Norsunder war of the late 4700s, when a couple of Old Sartorans resumed life in the world, it was not known if this was something the mages did, or other races. The figurative language and the ancient paintings and art made both interpretations possible.
It is also surmised that many mages chose to take the form of a tree, or one of the great root-community plants, for a time of meditation and other-awareness.
One last note that must be added: as is well known to Gardeners' Guild members, especially in the Southern portion of the world, the Rose Guardeners of Alsais are an older family even than the royal Lirendis, and they insist that they communicate with the ancient rose vine in the Queen's Rose Garden. There are two more of these extremely old rose plans elsewhere in the world, and there, too, humans who work with them insist the roses talk. "How to roses talk?" "Like roses, of course." It is up to the seeker to determine the truth or facetiousness of these statements.
The morvende and maulan solved the food question by refusing to eat any creature who moves. They confine their meals to seasonal crops and that which drops from trees. Outsiders do not know the number of nuts grown and harvested by these populations, but over the many centuries the variety has become astonishingly large.
The debate even extends to tubers and wheat, etc--can plants be killed? The maulan insist the hervithe say that carrots, etc, do not experience negated life like trees do: that being consumed in a fashion changes their state, and adds 'being' to the consumer, otherwise they return their being to the ground. These questions still are unresolved, though there are laments about the nature of being an aleatory creature who must consume but desires not an existence based on consumption. There are entire language categories, in fact, that deal with these quesitons of being.