"My mare has episodes of colic..."

"My mare colics in the hours that follow a stressful event (being separated from her foal, travelling, being turned out to grass after a long spell being stabled…). She suddenly starts to swell up and unfortunately this is a reoccurring event. 
Should I change something in her feeding in order to help limit these episodes of colic?"

The Reverdy answer

It would seem that your mare has a sensitive microbiota (= gut flora) that can be very quickly disrupted by an emotional or dietary stress.
There is very little scientific research on the subject, however one study has demonstrated that mares who had colics following foaling, showed changes in the proportions of intestinal bacteria in the days proceeding the colics1. It would seem that a link exists between the microbiota and episodes of colic.

In this case, the hypothesis would seem to be that certain bacteria develop more than others following a stress, and therefore are at the origin of a large production of gas, causing pain and having serious consequences for the mare.
Emotional stress and dietary stress (a sudden dietary change without a transition) have an influence on the intestinal microbiota and, this influence can be of more or less of importance depending on the initial bacterial balance in the horse2,3.

In this case, stress for the mare must be kept to a minimum:

    • Emotional: by ensuring the mare is in a calm and stable environment, with a regular routine,
    • Dietary: the best method of stabilising the intestinal microbiota and to keep the mare occupied, and thus reduce dietary and emotional stress, is to feed at least 2kg of hay per 100kg live-weight (so 10kg for a 500kg horse) per day.
      The hay must be good quality, but it’s best to avoid hays made from legume crops (like luzerne) which can be the cause of fermentation in the large intestine. Sudden dietary changes must also be avoided (don’t suddenly turn the horse out to grass without a transition period), and divide the concentrate ration into as many meals as possible, in order to avoid starch passing directly into the large intestine. If so, the starch will engender unwanted fermentations in the large intestine, which is what we are aiming to avoid. It is equally of interest to replace part of the energy provided by starch by oil (about 150ml per day to replace approximately 500g of feed). The mare must also have free access to fresh water.

We also recommend adding Flora feed supplement to the diet (up to 3 measures may be given daily). This will supply postbiotics, in the form of assimilation factors obtained from the lactic fermentation of germinated barley grains and organic cereal ferments, whose role is to feed the “beneficial” microbiota, as well as probiotics, in the form of live yeast with the aim of maintaining an optimal microbiota balance for a healthy digestive system.

Further reading:

1. Weese, J. et al. Changes in the faecal microbiota of mares precede the development of post partum colic. Equine Vet. J. 47, 641–649 (2015).
2. Schoster, A., Mosing, M., Jalali, M., Staempfli, H. & Weese, J. Effects of transport, fasting and anaesthesia on the faecal microbiota of healthy adult horses. Equine Vet. J. 48, 595–602 (2016).
3. Daly, K. et al. Alterations in microbiota and fermentation products in equine large intestine in response to dietary variation and intestinal disease. Br. J. Nutr. 107, 989–995 (2012).