Updated: Sep 5
Some people find it hard to wrap their head around the fact that you can have multiple horses on the same pasture and it will affect them all differently.
This means the horse’s pasture grass is often dismissed as a cause of health, movement & behaviour issues - all the horses can be eating the same forage but not all of them develop issues.
- Some will seem not to be affected at all. - Some will have mild and some more serious/acute ‘symptoms’. - ‘Symptoms’ can be completely different between individuals.
HOW the individual horse is affected depends on the interplay between the changes in nutrient composition of the grass over the previous few days and the nutritional/metabolic status of the individual horse at the time.
If the in-built coping mechanisms of the metabolism have already been working hard and then weather conditions cause further insult then the horse will develop acute ‘symptoms’ overnight.
For example horses who have salt added to a daily feed rather than relying on a salt lick, and who are ‘up’ on their vitamins and minerals - especially calcium and magnesium, are not necessarily immune but are less susceptible. They have ‘something in the bank’ to buffer these changes.
Young horses are more susceptible because they have an increased requirement for macro minerals anyway.
People also ask: 'are certain breeds more likely to be affected eg thoroughbreds or chestnuts with white sox?' The answer is NO - in both cases.
In our experience based on thousands of horses over the last 18 years:
SIZE DOES make a difference – for example head-flicking is more common in larger horses while head-flicking minis are very rare! EMS & laminitis is more common in smaller horses
Larger horses are much more of a challenge due to their larger volume and correspondingly higher requirements.
AGE also makes a difference particularly with Neuro/Musculo/Skeletal issues. We consistently observe that Sacro-Iliac, locking stifles and a variety of other gait abnormalities are more common in young horses.
This is not surprising because growing horses have an increased requirement for nutrients especially the macro-minerals.
Photo - large and small - both problematic when their forage was green grass.