New thinking suggests that both shivers and stringhalt (as explained here) may have similarities to certain muscle disorders that can be managed effectively with a change in diet.
Findings from a researcher in America suggest that both these conditions may be related to ERS, the muscle syndrome that we most commonly refer to as “tying up”.
While the name of Dr Stephanie Valberg is synonymous with defining certain cases of ERS into two new syndromes, polysaccharide storage myopathy (PSSM) and recurrent exertional rhabydomyolosis (RER), a second researcher, Dr. Beth Valentine, a vet from Oregon State University, has now made the link between a related condition, equine polysaccharide storage myopathy (EPSM), and muscle conditions of heavy breeds.
In her opinion, shivers and stringhalt are manifestations of EPSM in these horses.
In susceptible horses, both conditions seem to centre on the rapid accumulation of glycogen in muscle cells after starchy, sugary meals, which in turn causes damage to the cells. Management practices have been proposed to reduce the likelihood of occurrences, involving a chance in diet and exercise patterns.
Dietary changes involve reducing the amount of starch and sugar in the diet, replacing them with fibre and oil, with training adaptations to make muscles burn fibre and oil as energy sources.
These changes are not a panacea, however, and will not eradicate shivers or stringhalt in every case, pointing to the gaps in our knowledge about the interactions between the nervous system and muscle function.
Feeding the shiverer