Hay Belly
My 23 y.o. mare Lea has what most horse people know as a “hay belly”. Although she still has what I believe to be the most beautiful head and neck of a horse I’ve ever seen, she came out of last winter with a large, sagging mid-section despite a moderate (range 5-6) body condition score. This outline coincided with some muscle wastage along her topline and a steep dip along her back from the withers. Lea was diagnosed with PPID or “Cushings Disease” approximately 2 years ago, and has struggled with osteoarthritis and pain issues.
One of the symptoms of PPID is ligament and muscle weakening, which may lead to suspensory ligament or tendon injuries in the lower limbs or an overall “sagging” of the skeleton and its tensegrity (i.e., holding strength). This may lead to a dropped or loose appearance of the topline and belly. Hay belly may also be the result of high levels of indigestible fiber (e.g., lignin) from poor quality or over-mature hay that does not ferment easily within the horse’s hindgut. Due to aging or disease, some horses may also digest and ferment forage less efficiently. In both cases, the fiber is retained longer during digestion, increases “gut fill”, and appears in the form of a distended belly. Any disruption in the microbial populations responsible for fermentation in the hind gut, due to indigestible fiber or otherwise (e.g., changes in feed, NSAIDS use, stress, etc.) may also produce gas and cause the horse’s belly to bloat.
In the case of Lea, her hay belly was probably the result of PPID plus digestive upset caused from past NSAID use and stress. We did a forage analysis of the grass hay forming the bulk of Lea’s diet to determine its Acid Detergent Fiber (ADF) value, which represents the amount of indigestible fiber in the forage. A percentage greater than 45% is more likely to cause hay belly since the fiber remains within the hindgut longer, but Lea’s hay was found to be within acceptable parameters (31.6 %). We removed rice bran from Lea’s ration and increased ground flaxseed in the ration, hence creating a more positive omega profile in Lea’s diet that supported anti-inflammatory effects. We also changed and increased Lea’s mineral & vitamin intake to balance her nutrition, boost immune and metabolic function, and provide essential amino acids for topline health. For Lea, it became key to maintain her feeding, exercise, and social routine to manage stress and decrease the opportunity for digestive upset. We also addressed some osteoarthritis pain issues for Lea without use of NSAIDS. Over 1-2 months we did see a slight change in Lea’s hay belly and less signs of discomfort.
