Craig asks:

“A couple of months ago I read about getting the most out of your dog in the field, and one comment was to not feed your dog for twelve hours before going afield, there were other factors as well, conditioning etc. but this jumped out at me as odd. I would agree that you would not feed them, and go right out and run them full tilt for two miles. The claim included a dog will run better on an empty colon. What am I missing?”

Much of this type of advice seems to be in regards to avoiding gastric dilatation - volvulus (bloat).  Bloat is often studied and remains a near complete mystery.  For reasons still unknown, a dog's empty or full stomach seals up and traps gas.  Once that happens, the expanding stomach and the dog's internal geometry combine to twist the stomach which reinforces the seal and shuts off blood-flow to the stomach.  With proper care the tissue damage can kill up to 30% of the dogs.  Without proper care the stomach ruptures.  It's no wonder folks will do almost anything to avoid GDV.

I took a look at the most recent studies which didn't turn up much.  GDV is more common in Giant breeds than smaller and most common in Large breeds.  It is more common in dogs who are fed once a day than the rest, but not exclusive to them.  Bloat occurs slightly more often in dogs that eat a food that has a fat or oil in the first four ingredients.  One study in military dogs found that half the cases occurred in November, December and January, but they only had 48 cases to look at.  The weather has been studied as a factor, and eliminated.  There is no apparent breed correlation.  They have not studied the effects of Patriots Football, but don't laugh, a study trying to correlate the Pats with emergency room visits got published (and there appears to be none).

Sports nutrition is advancing at a rapid pace in humans and I try to draw from that information.  Those who say dogs shouldn't eat before exercise today are as misguided as those who said athletes shouldn't have water at practice.  We now know that they don't just need hydration during practice, but they need to pre-load their systems, starting the day before.  An athlete who starts drinking when he is thirsty is already behind and trying to catch up.

The same is true for calories.  Specifically the kind of calories our body can store and use short-term.  Marathoners have been "carbo-loading" for years.  Dogs don't use carbs the same way people do, but they need them. 

Unfortunately my experience is anecdotal, but I run my Corgis in agility.  I noticed that despite being "fitter" than the other dogs in class, they wore down earlier.  They keep up with GSP's every day.  I feed a 40% protein 20% fat dog food, so I assumed I was doing everything right, nutritionally.  I started feeding a small portion of high protein, high fat and calorie dense food (usually her normal kibble) a few hours prior to agility.  The difference has been night and day.  I would never run my dogs on a completely empty stomach in any strenuous activity.  I would also recommend feeding small, calorie-dense snacks whenever possible.

I think if everyone (bipeds and quadrupeds) consumes a reasonable and nutritious breakfast, they are off to a good day afield.  Consuming high-quality, calorie-dense food and good hydration before, during, and after hunting will help keep energy levels high all day.

Purina had a (now defunct) product based on the need to replace glycogen in a dog during exercise.  The Pro Plan Performance Bar was to be fed prior to hunting, at each 45 minute interval, and immediately following hunting.  Its main ingredient was Maltodextrin, which metabolizes to glucose in the bloodstream which converts to glycogen in the muscles.

Wakshlag JJ, Sneddon K, Otis AM, et al. The effects of post-exercise supplements on skeletal muscle glycogen repletion. A manuscript submitted to the American Journal of Veterinary Research, 2003.

Dr. Rizner is a veterinarian and animal chiropractor who practices at York County Animal Hospital in Arundel Maine.  She has special interests in pain management, canine reproduction and geriatric and performance animals.  You may submit a general interest question to: