Mid-summer horse feeding update

Beware of feeding weed-ridden hay to horses; the risk of consuming hoary alyssum is greater in light of this summer’s weather.

The summer of 2012 will be one of those summers that will be talked about for years to come. “Remember the year it was 80 degrees in March and over 100 in June and again in July, and how muggy it was”, will likely be some of the memories being created this summer. The responsible horse owner has been careful to provide shade and plenty of fresh water, as well as taking extra steps to ensure that their horse does not become dehydrated during riding. So have we taken enough steps to have all the safety bases covered so far in the summer of 2012?

Probably not. The hot temperatures and lack of rainfall that most of Michigan has been experiencing this summer will produce further concerns.

Pastures have turned dry and yellow and have gone dormant, creating additional need for supplementing forages; the hay crop appears to be significantly down from the last two years’ bumper crop. The 2012 short hay crop will lead to higher prices, so plan ahead and try and buy your winter supply now, or at least lock in your winter supply in some mutual arrangement with your supplier.

Caution will also need to be taken when shopping for and buying hay this year. Both first and second cutting hay will have more weeds than in a more normal growing year. Weeds still manage to grow when all the desirable crops are droughty from lack of moisture. Marginal fields that tend to have more weeds are often harvested in “short hay crop” years, because the increased price for hay will make it economically feasible for suppliers to harvest those, often weed infested, poor producing fields.

Hay quality is often determined by if the hay was rained on or not. Nearly all hay harvested for horse hay this summer will not have any rain on it, therefore moisture-created molds will be much less of a concern than in most years. Second, cutting in general will be of good quality, but the smaller crop will drive the price upward. Hoary alyssum continues to thrive in Michigan and seems to be spreading, and in a dry year such as 2012, there appears to be heavy infestations of horary alyssum.

Hoary alyssum is toxic to horses, so educate yourself to know what it looks like and how to identify it in your horse’s hay.

  • Hoary alyssum is toxic only to horses. It’s a perennial weed that is commonly found in pastures and hay fields after areas experience drought.
  • Hoary alyssum is light green to gray in color with white flowers.
  • The seeds are small and oblong and easily seen in baled hay.
  • Horses that ingest hoary alyssum might experience stocking-up or swelling of the limbs, founder, and even death.
  • The toxic dose of hoary alyssum is estimated at 20 percent (of the plant ingested) in hay, but is known to affect some horses differently. Some horses have a zero tolerance to hoary alyssum.

Pay attention to what your horse does not eat from hay. Horses will generally sort out any weeds from the good grasses and not eat them, but if the weeds are left in the stall and the horse is encouraged to clean up all the material before more hay is fed, they may eat questionable weeds and the problems may begin. Keep in mind that each horse is different and may have a different tolerance level.

For more information on horse hay see Michigan State Univesity Extension’s Bulletin #E2305.

Related Articles