The Story of Equine Atypical Myopathy: A Review from the Beginning to a Possible End
Table 3
Risk and protective factors for the development of atypical myopathy.
Risk factors
Protective factors
Demographic data
Age
Young horses (<3 years)
Sex*
(i) Colts (ii) Stallions
Geldings
Body condition
(i) Thin (ii) Normal weight
(i) Overweight
Management practices at the horse level
Deworming
Frequent deworming
Vaccination
Regular vaccination
Occupation
Training
Pasturing
Full-time pasturing (all year round)
(i) Not at pasture (ii) <6 H per day at pasture (iii) Weather-dependant pasturing in spring and in autumn
Food and water
Supplementary feeds
Hay in autumn
(i) Supplementary feeds in autumn (except hay), in particular silage and complete mix (ii) Supplementary feeds in winter, in particular straw, silage, complete mix, and corn (iii) Supplementary feeds in spring (iv) Supplementary feeds in summer (v) Salt block (all year round)
Water supply
(i) Distribution network (ii) In tank or bath tub
Pasture characteristics
History
Dead horses on the pasture in the past
Grass land
Lush pasture in winter
Incline
(i) Sloping pasture (ii) Steep slope
Gentle slope
Trees
(i) Surrounded by or containing trees (ii) Presence of dead leaves (iii) Presence of dead wood
Humidity
(i) Humid pasture (ii) Pasture surrounded by or containing a stream/river
Management of the pastures
Spreading of manure
*Age was identified as a confounding variable regarding the risk factors associated with the animal’s sex. Sex is linked to age, as “gelding” is a status that follows castration, a procedure usually performed in males >18 months old (i.e., the most risky age for AM). Because females are more frequently kept at pasture than males, a higher percentage of AM cases is females.
