Obesity is a serious problem in horses as in some cases it can lead to laminitis and founder.  Laminitis is a painful foot condition that can even end in the horse’s death in some cases.  It is difficult to get horses to lose weight and still get them exercise as most horses gain weight from eating grass in the pasture, not from grain or concentrates.  Exercise is really important to aid in weight loss. Also, horses generally have a better mental attitude in a pasture versus being kept in a stall. 

However, unless you have a large area fenced with no grass, turnout can be difficult but one option is a grazing muzzle.  A grazing muzzle has been shown to decrease grass ingestion by 30-80%, depending on the grass and muzzle used.  The major problem my clients have is keeping the muzzle on the horse as some horses are really good at getting the muzzle off and some muzzles are certainly better than others.  The muzzle allows the horse to get some grass inside the muzzle but prevents a large portion from being eaten. 

Dr. Amy Burk was concerned about the mental stress the muzzle could cause, so she developed a study using six miniature horses that were in adjacent grass paddocks 24 hours a day.  They rotated two Minis at a time through three 21-day treatment periods: no muzzle, muzzled for 10 hours per day, and muzzled for 24 hours per day. Miniature horses were used because they commonly are obese and need to lose weight.  The horses were recorded hourly and their weights were checked routinely.  Heart rate and salivary cortisol levels were also measured to check for stress.  The results showed that no negative effects occurred.  Minis muzzled for 24 hours showed no evidence of stress and lost weight compared to other groups that gained weight so if your horse is overweight, a grazing muzzle is an option to consider and still keep your horse in the pasture.