Question
My senior Quarter Horse gelding Cobbles has heaves and pars pituitary intermedia dysfunction (PPID). I manage him outdoors on good-quality grass pasture and timothy/alfalfa hay. In addition, I feed him 6 lb (2.7 kg) beet pulp (dry weight) and 2.5 lb (1.1 kg) of ration balancer daily. I also supplement with 2 lb (0.9 kg) stabilized rice bran and an electrolyte. I am interested in adding chasteberry to his diet along with something to help muscle atrophy. What would you suggest?
Answer
I have a few recommendations and some questions to help me better understand Cobbles’s current diet and management. The questions are simple: do you know how much hay Cobbles is consuming daily by weight, and how many meals are offered?
The amount of beet pulp fed leads me to believe he may not be consuming enough forage if pasture grass is not available year-round. I imagine you may also be feeding beet pulp to reduce the amount of long-stem hay needed as it can exacerbate airway disease. Although beet pulp is an excellent source of calories and fiber, it should not be fed to replace forage. Many nutritionists recommend that beet pulp be fed in meals no larger than 2 lb (0.9 kg). If you want to limit hay intake, but not forage consumption, you may consider switching out some of the beet pulp for hay pellets, hay cubes, or dampened chopped hay.
From the snapshot you provided, Cobbles does not look underweight. Given his diagnosis of PPID, a photograph without a saddle may reveal some loss of topline musculature, a common symptom of the disorder. Offering a balanced diet with quality protein sources, maintaining regular exercise, and providing appropriate medications (pergolide) are some of the best ways to reduce muscle loss in horses with PPID.
Providing a low-intake ration balancer is essential for easy keepers with metabolic conditions. If you are concerned about him getting enough amino acids even after the addition of a ration balancer, you could consider adding a supplemental source of branched-chain amino acids to support protein synthesis and delay onset of fatigue.
Muscle health can also be supported with antioxidant protection from natural-source vitamin E, the best form of vitamin E for horses, especially when compared to synthetic forms (dl‐alpha‐tocopherol). Nano‐E is a water‐soluble, natural‐source form of vitamin E that is rapidly absorbed, providing protection to the muscle through its antioxidant mechanisms.
Although Kentucky Equine Research has not investigated chasteberry supplementation, other research groups have. German researchers supplemented chasteberry to PPID horses already prescribed pergolide. They found that horses on pergolide and chasteberry had higher ACTH levels than horses on pergolide alone, the opposite of the intended outcome. The researchers concluded that the chasteberry may interfere with the effects of pergolide. Given this, consult with your veterinarian before introducing chasteberry to the diet.
In place of chasteberry, I suggest adding a source of long-chain omega-3 fatty acids to support metabolic and respiratory health. These omega-3 fatty acids play an important role in the inflammatory process by inhibiting activity of the enzyme cyclooxygenase, which enables inflammation and pain. Because of its anti-inflammatory properties, omega-3 fatty acids have been found to help horses with heaves. Research has shown marine-derived sources of DHA and EPA—the most important long-chain omega-3s—are far more effectively utilized by the horse than ALA, which is a short-chain omega-3 derived from plants, like flax. EO-3 is a palatable minty-apple flavored oil that incorporates efficiently into cellular membranes and decreases the production of inflammatory pathways. Improvement in insulin sensitivity and glucose tolerance are also a benefit of long-chain omega-3 supplementation.
