Hi Ceie
If your horse has insulin dysregulation and needs metformin or an SGLT2 inhibitor such as Invokana (canagliflozin) to control insulin, should they still have access to grass?
Medication can produce much better blood results. But a lower insulin result while medicated doesn't necessarily mean the underlying problem has gone away.
Medication doesn't make grass safe
Metformin and SGLT2 inhibitors work differently, but the principle is the same: medication shouldn't be used to make an unsuitable diet appear safe.
If insulin has been sufficiently difficult to control that medication is required, we also need to minimise the dietary factors continually challenging the insulin response. And one of the hardest things to control is living grass.
Short or brown doesn't mean low sugar
A field can look short, yellow, stressed or almost bare and still be unsuitable for a horse with poorly controlled insulin.
The sugar content of grass changes with sunlight, temperature, rainfall, drought stress and growth. This is particularly important when rain follows prolonged dry weather and grass begins actively growing again.
Hay gives us more control
Unlike grass, hay can be analysed. We can measure ESC and starch and establish the hydrolysable carbohydrate (HC) level, giving us a much more controlled source of carbohydrate.
For horses with significantly dysregulated insulin, replacing grazing with a controlled amount of analysed, suitably low sugar and starch hay can therefore be an important part of management.
The goal isn't just a lower blood result. We want medication and management working together: controlled forage, appropriate body condition, exercise where safe and veterinary treatment, producing the lowest and most stable insulin response possible.
Grazing may then be reassessed with your vet as insulin regulation improves. Because we don't want to discover that the only thing keeping insulin down was the medication while the dietary trigger remained unchanged.
None of this is a reason to change or stop any medication your vet has prescribed. Speak to them before altering treatment or turnout.
Test. Don't guess. Especially when managing insulin dysregulation.
