I have an old animal husbandry text (1943) that gives descriptions of "sugar mules", "cotton mules", "farm mules", and "army mules". These mules were bred for work on sugar and cotton plantations and for general farm and military work. Are mules bred today for different purposes. I know that there are draft mules and I've seen miniature mules produced from Shetland mares. I'm just curious about the subject. Thanks.