Friday, April 20, 2012

Feed and Feeding

So I know some general principles about digestive tract anatomy and feeding management for horses, but I recently went through the exercise of calculating a more specific estimate of what Delphi is currently consuming.

Before we get the snapshot of Delphi's current menu, some basic principles:
  • Horses have a peculiar digestive tract when it comes to domestic livestock and can be divided into the foregut and hindgut; the foregut accounts for ~35% of the capacity of the digestive tract--pigs' foreguts can handle up to 65% and cattle up to 90%-- so the uniqueness of horses' digestive anatomy is apparent. This relatively small stomach size makes the rate of passage of ingesta relatively fast, and larger meals pass even faster than smaller meals.
illustration of horse digestive tract
Anatomy of the horse digestive tract with relative sizes.Adapted from Feeding Management of the Equine (F-3973
Oklahoma Cooperative Extension Service).
  • Horses should consume 10 to 12 gallons of water per day. Water buckets should be changed at least twice daily to avoid becoming stale or contaminated since horses do not readily tolerate stale or dirty water.  Providing a trace mineralized salt block designed specifically for horses ad libitum may help promote drinking and replace sodium and chloride loss from sweating.  
  • A very general rule of thumb is horses should consume greater than or equal to 1% of their body weight in forage per day, and less than or equal to 1% of their body weight in concentrate. For Delphi (weighing in at ~1200 pounds) that means at least 12 pounds or more of forage (grass/hay) and no more than 12 pounds concentrate per day. Horses in moderate to heavy work have greater feed requirements than the average "rule of thumb" horse.
  • We can assume that a horse grazing on adequate pasture (and supplemented with grain) will consume at least half of their daily dry matter intake from grazing. Since Delphi is out ~12 hours per day, this means she probably eats about 6 pounds of grass daily.
  • In their natural state horses spend ~60% of their time eating and grazing; resting periods are rarely separated by more than three hours of non-eating behaviors.
On to Delphi's snapshot:
  • Delphi's stall has two 5 gallon water buckets, and she has access to a fresh water tank ad libitum in her turnout paddock. She typically drinks more than both her buckets during the day-- at least 12 gallons per day-- probably more. She has stall access to a trace mineralized salt block for horses, a Himalayan salt lick, and receives an electrolyte supplement in her morning feeding.  So CHECK.
  • Delphi gets fed a concentrate mixture of sweet feed and pellets that is approximately slightly more than 1 pound per dry quart. She eats "one scoop" (her feed scoop is 4 dry quarts) two times daily for a total of ~10 pounds concentrate daily over two feedings spaced 11 hours apart. So CHECK.
  • Delphi receives two flakes of quality coastal hay three times daily, plus an extra flake mid-morning so she never has to spend more than three hours in her stall without forage in front of her. The average flake of hay is 3 to 5 pounds, so Delphi probably consumes ~21 to ~35 pounds of hay forage daily, plus the ~6 pounds of grass she eats while she's at paddock overnight.
  • Delphi is definitely getting above and beyond the "rule of thumb" of "12 pounds or more" of forage, which is good since Delphi is in strenuous dressage training five or six days a week with an active show and clinic schedule. Better that she gets her extra feed requirement from forage rather than concentrate. So double CHECK.
Delphi and Lola doing what they do best.

Sources: North Dakota State University Department of Animal and Range Sciences, and University of Kentucky Cooperative Extension Service.


Anonymous said...

Nice analysis, you a very conscientious horsewoman who cares greatly for Ms. Delphi! She looks great too btw!