Actually it should be “uh oh September” but that is both less alliterative and this year not so appropriate. September 2014 was particularly warm and the temperature was rarely lower than 15°C. But now October has arrived and the first really cold nights are just around the corner. Along with the increased dangers of higher fructose content in the grass.

We tend to think of springtime as being the most dangerous period for laminitis in our horses – and to a greater extent, that is true. Low temperatures and plenty of sun means a high rate of photosynthesis but just about no growth which leads to fructose being stored in the plant for later growth. Added to this the fact that many horses are kept indoors throughout the winter because owners believe that their horses are incapable of withstanding temperatures below about 10˚C and they are worried about them getting wet. The state of the pasture is also a consideration. All this means a sledgehammer blow to the system during spring turnout after such a period of “abstinence” and some horses (actually a surprisingly high number) are not capable of coping with this change.

But now the autumn is upon us, even with the possible promise of warmer days in mid-October, we are starting to run into the same sort of circumstances that increase the amount of fructose in the grass. Only now, the danger moment is shifted from the morning to the evening. A sunny day with temperatures not reaching above about 15˚C will mean higher fructose levels in the afternoon and evening rather than early mornings.

Because our horses have been out all summer, they are less prone to the dangers of high fructose levels but those horses that are particularly sensitive need more protection.

This table may be of some help determining the danger moments:

Weather Plant Metabolism Fructose Levels
Night Temp Day Temp Sun Photosynthesis Growth morning afternoon evening night
<0˚C <0˚C No No None 3 3 3 3
<0˚C <0˚C Much Much None 5 5 5 5
<0˚C <15˚C Much Much Low 5 4 4 3
>5˚C <15˚C Much Much Low 1 3 4 2
>15˚C >15˚C Much Much High 1 2 3 2
>15˚C >15˚C No Little Much 1 1 1 1
The risk on a scale from 1 (low) to 5 (very high)