Agriculture Reference
In-Depth Information
antioxidants, vitamins and minerals that might counteract on the metabolic
imbalance created by AM and support muscle function. Supplementary
feeding can consist of silage, straw, complete mix, corn or oats. However, one
must be careful with giving hay in the autumn (Votion et al. 2009). Hay is
often given from the ground and thus possibly stimulates contact with soil and
the causative agent. Hay can also be a source of bacteria and fungal spores
exerting potential toxicity especially in humid environment.
2.2.3. Preventive Measures Based on Risk and Protective Factors:
Pasture Characteristics and Management
A history of previous dead horses on the pasture, regardless the cause and
date, was found to be a risk factor for AM (Votion et al. 2009) and should be
avoided whenever possible. Pastures where AM has declared in the past
remain a danger for horses grazing on it, as pastures have been described to
declare AM in successive years (Votion et al. 2007; van Galen et al. 2010).
The etiological agent probably remains present at the pasture and it can exert
its toxicity during specific seasons and environmental and climatic conditions.
Pastures that are lush during the winter season were found to be a risk
factor for AM. These data should be interpreted with caution, because a
discrepancy between observations by scientists and horse owners was noted.
Owners often described their pastures as having lush grass, but regularly
scientists found them to be bare (Votion et al. 2009). Additional study
strengthened the observation that the majority of pastures was bare (66%) and
only a minority were pastures with lush grass (29%) (van Galen et al. 2010).
Sloping pastures, especially those with a steep slope, should be avoided to
prevent AM (Votion et al. 2009; van Galen et al. 2010). This can be a
confounding effect with the geographic area where AM regularly occurs, but it
might in one way or the other also play a role in creating an optimal
microclimate for the causative agent to cause AM. Horses grazing on sloping
pastures probably also use their postural muscles more intensively and this
might add to the energetic imbalance when muscles are affected by AM.
Pastures that contain dead leaves and dead wood form a risk (Votion et al.
2009; van Galen et al. 2010) and therefore dead leaves and wood should be
removed from the pasture and be burned. Pastures surrounded by or containing
trees were also determined to be a risk factor, and almost for all described
cases trees were present at their pasture (34/35 pastures (Votion et al. 2009)
and 194/198 pastures (van Galen et al. 2010). Trees, dead leaves and dead
wood might contain the causative agent (for example a phytotoxin or a
mycotoxin), favour its development, and/or contribute to its toxicity or act in
