Many rural dogs, or urban dogs on vacation to an equine hot spot, discover horse manure and develop a horse manure eating habit. Most dog owners find this pretty gross, and this activity can be dangerous to your dog for a couple of reasons. First of all, a dog that constantly goes into the horse pen or pasture to find some tasty horse manure is at risk of being stepped on or kicked by horses who do not appreciate his presence! Also, many dogs experience a toxic reaction to medications given to horses that can be passed in horse manure. The most common cause for concern is the medication ivermectin, which can be fatal to some dogs, and which is commonly used in livestock, such as horses, to control internal parasites. Horse manure containing ivermectin can be fatal if a large dosage is passed through to the dog, or if your dog belongs to one of the breeds that is susceptible to ivermectin toxicity. Keeping your dog from ingesting horse manure not only is a concern from a cleanliness point of view, but also is important to keep your dog safe from harm.
Why dogs love to nosh on horse manure is not entirely understood. Grazing livestock do not always digest all their feed, so if their feed contains tasty grains or molasses, and this passes through in part or whole in manure, this may attract your dog to the manure. If your dog is getting this reward from eating horse manure, you need to implement training to teach him not to eat horse manure and provide a reward for leaving horse manure alone. If your dog has been eating horse manure for an extended period of time, and this habit and reward has become well-established, it will be harder to break than if your dog has just discovered the joys of horse manure! Another complication is that it may be difficult to control your dog’s access to horse manure in a rural settings, so consistency and supervision will be required.
Because of the environment in which dogs have access to and ingest horse manure, diligent effort and supervision will be required to get control of this behavior. Establishing firm control of your dog with voice commands so you can implement 'leave it', 'look at me', and 'down-stay' commands to control horse manure eating behavior will be required. You will need treats to establish these alternate behaviors. You can also use a noise making device, or a training collar to introduce a negative association with the behavior. Electric collars should be used carefully, with only the lowest level of stimulus required to get a reaction from your dog. If you are opting for this option, be sure to read the instructions that come with the product carefully and ensure you understand how to use the collar correctly.