Changing Hay Sources for Horses

As a horse owner, I have moved quite a few horses around and recently moved my gelding to a new boarding facility, so thought this would be a good opportunity to share one aspect of my experience. 

To help maintain as much consistency in his routine as possible, I made sure that I had 2 weeks’ worth of hay to take with me to help keep his diet consistent throughout the move and to allow for a gradual transition to the new hay. 

When I told the barn managers at the new facility that I was bringing a few bales of hay over, they seemed a little surprised at this and told me not to worry about it, because they had really high quality hay.  I asked them if they would recommend a sudden change in a horse’s grain ration, and immediately they said of course not, due to colic risk. I replied, “Then why would you switch their hay cold turkey, when it makes up 60 – 70% of the horses diet?” and watched their expressions as they realized the point I was making.

As a result, along with keeping his grain ration and meal times consistent with the previous routine, a gradual transition from the previous hay to the new hay was done over a 2 week period.  For the first couple of days he received his “old” hay only, and over time we incrementally replaced a small portion of his “old hay” with the “new hay” so that at 2 weeks post-move, he was completely switched over without any problems or decline in performance. 

As horse owners, it is important to keep in mind that ANY sudden changes in diet, including fresh pasture and hay, can disrupt the environment in the gut where communities of microbes reside.  Consequently, this disruption in the microbial population and digestive process can put the horse at risk for GI upsets (e.g. excessive gas production, colic, diarrhea, discomfort, etc.). The energy and nutrient content in hay can vary drastically depending on the plant species, geography, soil conditions, plant maturity at harvest, climate conditions, baling and storage methods, etc.  Even hay that comes out of the same field from consecutive cuttings can have large differences in quality and nutrient content that should be considered. 

It takes approximately 3 weeks for the microbes in a horses gut to adapt to dietary changes, thus making slow, gradual transitions over a 2 – 3 week period important to help prevent GI upset.  When it isn’t possible to make a full two week transition, then allow for as much of a gradual transition as possible even if is only over 2 – 3 days.  Providing dietary pre- and probiotics can also help support gut microbes through dietary changes especially if they are rapid.

Judging Hay Quality for Horses

Because hay is such a common part of a horses diet, judging quality on visual inspection is important, as lab analysis is not always easily available.  Here are three simple things to look for to help you select the best hay for your horses and your money.

  1. The initial check that most people are familiar with is color and smell.  Horse hay should be bright green and smell slightly sweet.  Brown hay indicates either a problem in the baling process, such as being rained on, or age.  Acrid or musty smells generally indicate the presence of mold.
  2. Another sign of good horse hay is the leaf:stem ratio.  The more leaves, the better, since the leaves are where most of the nutrition in the hay is stored.  Hay that has too many hard, woody stems is difficult to digest.  Even if it cheaper, most horses will pick through and leave the bulk of the stems behind, costing more in the long run.  High quality hay is fine-stemmed, pliable, and full of leaves.
  3. Type of hay is another factor.  Grass hays, such as timothy or orchard grass, generally provide sound basic nutrition.  The higher the concentration of legumes, such as alfalfa or clover, the higher the energy content.  High quality alfalfa is generally better than high quality grass hay, but good quality grass hay can be better than average quality alfalfa hay.

The best thing, in the end, is to have hay tested.  This is not always feasible for every load, but if your hay source is consistent from load to load, this may be a good option to get a general feel for what nutrients your hay contains.