This improvement improves the amount of Food a Villager can carry, which is useful when hunting so the Villagers do not have to make as many trips. It also improves the rate at which Cows, Goats and Pigs fatten.  Fattening animals have more Food in them the longer you wait before killing them. With Husbandry, that wait is shorter. 

In conjunction with the development of farming and the domestication of animals, new techniques in husbandry (for carrying, storing, and preserving food, for example) were developed to take best advantage of renewable food sources. Without improvements in husbandry, a high percentage of perishable foods would have become worthless. Important early advances in husbandry included: basket weaving; pottery making; salting of meat and fish; cheese making; smoking of meat and fish; and using animals for transport.