b'STACEY OKE, DVM, MSCor the past several hundred years horse owners have F struggled to care for charges afflicted with Monday morning disease, a crippling condition that affects horses after a day off from work. Although owners did recognizerefusing to move, with spasming the terrible discomfort their horsesmusclesthe level of discomfort far were in, recall that horses weresurpasses that of the usual aches the primary means of transporta- and pains associated with hard tion in those days, says Stephaniework. This is because horses suffer-Valberg, DVM, PhD, Dipl. ACVIM,ing from ER actually have sustained ACVSMR. Time off from tying-upsevere muscle damage. In fact, the was a major problem, effectivelyterm exertional rhabdomyolysis is grinding the transportation systemdefined as a breakdown or destruc-to a halt. tion of skeletal muscle cells associ-Horse owners didnt realize theated with exercise. conditions severity and, so, carriedTying-up is referred to as a syn-on with their riding and driving asdrome because it simply describes a the symptoms cleared. Now, wecollection of clinical signs describ-know Monday morning disease ising a disease process, says Valberg. actually the muscle disorder exer- There are actually many different tional rhabdomyolysis (ER), morecauses of tying-up, one of which is commonly referred to as tying-up,polysaccharide storage myopathy, or and it must be managed carefully.PSSM. If youve ever witnessed a horseValberg, currently the Mary Anne actively tying-upsweating,McPhail Dressage Chair in Equine March 2018 THE HORSE TheHorse.com 23'