cow manure is fine as long as it has been composted for about a 6 months to a year before putting on the garden, it tends to be hot, second to chicken manure which is the hottest. never mix fresh into a garden in the spring or you will burn your plants but if you add it in the fall and till it in it is fine by spring. so many different manures to add, llama/alpaca is the kind you can add mid season to you garden right on top of the soil same for rabbit,goat or sheep and they are all great manures and seed free because those animals digestive systems break down the seed hulls.seeds don't survive chicken digestive tract either but it also has to be composted for a year or more before putting on the garden.equine manures horse/donkey are kind mid range takes about 1-3 months for it too cool enough to be tilled in but it will have seeds that sprout, same as cows the seeds can pass threw the digestive tract of cattle and end up in your garden, the number one thing you will fight with cow manure is chick weed it spreads and is near impossible to remove. horse don't like chick weed so it won't have chick weed seeds but equine manure can have oat and grass seeds. hope this helps
