I know that Mudik are used for herding AND livestock guardians. They were often kept as alert dogs for the bigger and more intimidating guardians, like Komondors or Kuvasc. So, in other words, not only will they try to scare off the potential predator, they will also try to alert you on what's going on. They have a relatively curly coat, but it doesn't knot up all that much and it doesn't require a lot of grooming. They are small, their head no higher than your knee. They are rare in America, but I know there is a Mudi breed club if you want to know more.
Another breed I would suggest is the Beauceron. They are also known as the French Shepherd. They are more livestock guardian and they are big, but they have shorter hair that doesn't require a lot of grooming. And because one of the color markings is very similar to that of a Doberman, you don't have to worry about anyone trying to break into your property. These dogs are also rare in America, but they're slowly growing more popular due to their fantastic flock guarding skills. They can also be trained to herd.
More common dogs that are easier to find that I would suggest are Collies (there is a short haired variety, called smooth-coat), German Shepherds, Doberman (which were created to protect people, and eventually started being used as a flock guardian), Dutch Shepherd, Belgian Malimois, Berger Picard (also known as Picardy Shepherd), and all of the Bull Terriers.
Sorry about ranting, my career and profession specializes in dogs. Hope this helps!