Prevalences and clinical signs of polysaccharide storage myopathy and shivers in Belgian draft horses.

This study investigates the prevalence of two conditions (polysaccharide storage myopathy and shivers) in Belgian Draft Horses and endeavours to determine a link between them. The research found that a significant proportion of assessed horses had either condition independently, but a notable association between the two conditions wasn’t evident.

Methodology

• The study was a prospective cohort study involving 103 Belgian Draft Horses that were over a year old.
• Horse owners were surveyed about clinical signs of polysaccharide storage myopathy (PSSM), shivers, or hindquarter weakness (defined as weak muscling and propulsion in the horse’s rear).
• Blood samples were collected to measure serum creatine kinase and aspartate transferase activities, as well as serum selenium and vitamin E levels.
• Muscle biopsies were taken from the gluteus medius muscle to conduct histologic, histochemical, and biochemical analyses. A diagnosis of PSSM was established if abnormal amylase-resistant polysaccharide inclusions were detected in the histological analysis.

Results

• Out of the 103 horses, 37 (or 36%) were found to have PSSM, 19 (or 18%) had shivers.
• Significantly, only six horses (6%) had both PSSM and shivers, suggesting a weak association between the two conditions.
• On the other hand, 31 horses presented with only PSSM, and 13 presented with only shivers. Thus showing that these conditions frequently occur independently of each other.
• Thirty horses were identified with hindquarter weakness. Only 35% of the PSSM diagnosed horses and 58% of shivers diagnosed horses showed hindquarter weakness.
• A difference in serum creatine kinase and aspartate transferase activities was not found between the horses with and without the PSSM or shivers, indicating these biological markers were not significantly influential for these conditions. Similarly, there was no significant difference in serum selenium and vitamin E levels for horses with or without the conditions.

Conclusions

• The study concluded that PSSM and shivers are relatively common disorders in Belgian Draft Horses. However, no significant association was found between them, suggesting that these are, fundamentally, independent disorders.