Thursday, October 30, 2008

High Quality Horse Forage - Not Straw

Many of us subscribe to newsletters from  
I just received the first edition of their Nutrition e-newsletter, which links to an article called Nutritional Value of Forages . This hit one of my hot-buttons - perpetuating the myth that what we need for our horses is poor quality hay

The article quotes Jerry Chatterton, PhD, Research Leader of the USDA Agricultural Research Service, Forage and Range Research Laboratory in Logan, Utah:
“Sometimes a little straw filler might be okay,” he said with a smile. In other words, lower-quality forage will keep your horse busy longer, is less likely to make him overweight and/or laminitic, and he’ll eat more of it to get energy--keeping his stomach full and at lower risk of ulcers.

What our horses do need is the best quality horse hay and forage we can afford - not lower quality. Everyone, from growers to veterinarians to horse owners needs to review their definition of high quality forage for horses - which is different than the definition for high quality meat or milk production animal forage. This difference does not make it any lower quality - just different.

Low quality forage (including "straw", which can be extremely high in sugar) or insufficient quantities of forage can cause nutritionally-based problems. By the time you see the signs on the outside - dull coat, lackluster attitude, poor hoof quality - the changes have already occurred on the inside.

High quality horse forage

  • Should provide adequate but not excessive DE (digestible energy/calories expressed in Mcal per pound) and protein levels (by grams consumed, not “percent”) suitable for the horse’s age, reproductive status and level of work
    • The DE needs to be low enough that the horse can consume sufficient forage to ensure good gut function without taking in too many calories.
  • Should provide major minerals at least at the levels known to be required by horses (or have levels that are easily corrected)
  • Should smell good, be free of dust, mold or toxins and be palatable to the horse
    • Hays from species that are known nitrate accumulators or were grown in stressful conditions should be tested for safe nitrate levels
    • Horses may need time to adjust to the taste/smell of a new variety of forage
  • Should be tested for “safe” sugar/starch levels for horses who might be prone to IR (insulin resistance) or laminitis
    • Not all “fat” horses are IR; not all IR horses are fat
    • IR is not a “disease” – it is a metabolic evolution that allowed horses to develop and thrive in harsh conditions
Most of us are learning by now that the only way to accurately determine if a hay or forage is appropriate for our horse is to have it tested (see Analyzing Hay and Feeds) and using the results to determine if corrections are needed. While sugar and starch in forage, as emphasized in the article, are important for metabolically challenged horses, there is a lot more you need to know about the nutritional value of the forage you give your horse. What works for your pasture ornament may be inadequate in many ways for your performance horse, and what works for your performance horse when he is training/working might set him up for laminitis when he's idle. 

Forage testing (even if only done as "spot checks" for an idea of what you're feeding if you can't store large quantities of hay) is cheap insurance - at $30 to $50, a lot less than a vet bill. "Correcting" excesses and deficiencies by targeted mineral balancing can be done economically - often for a lot less than buying an "off the shelf" standard supplement which may or may not provide what's needed (and often adds a lot of "stuff" that's not needed).

So - when looking at forage for your horse, think in terms of the "best" quality you can afford. Take words like "rich" out of your vocabulary; they tell you nothing about your hay. Forget "old", "last year's", "poor quality" and "straw" when trying to find low sugar/starch hay.
Think in terms of how many Mcal your horse needs per day, how many grams of protein he needs, and calcium/phosphorus balance based on test results, not on whether it's "grass" or "alfalfa". Look and test for sugar plus starch equal to 10% or less for an IR or laminitic horse - low sugar/starch does not mean compromising on energy, protein or quality. Avoid excessively high iron levels in forage if you can - it may be an indication of poorly maintained fields or high surface contamination, and has been shown to be "pro-inflammatory". 

You can figure your horse's requirements in many places (see the  Analyzing Hay and Feeds article), find out what your forage supplies from the test results, then the rest is just addition and subtraction. (Well, maybe not "just" but not rocket science either. You might want to try on Dr. Kellon's basic nutrition class - NRC Plus - for starters.)
And use the straw for bedding your cows and goats.

Thursday, October 23, 2008

Winter Water Needs for Our Horses

As cold weather approaches (and already here for those in the North), we need to continue to pay attention to our horses' water intake. Horses who are used to obtaining some of their fluid from grasses may not increase their water intake as pastures brown up or as their winter ration begins to include more cured hay. 

Risks of Lowered Water Intake
Impaction colic, related to a diet of drier forage coupled with lessened water consumption is not the only risk to horses who drink less in cooler weather. Dehydration may also expose horses to increased respiratory problems. While I could find no direct equine references, in humans, dehydration is associated with poor mucus mobilization and clearance, with a lessening of a critical airway defense mechanism. (

The maintenance water intake for an adult non-working horse is around 5 L per 100 kg/BW (NRC 2007, p132). This translates to about 1.3 gallons for each 220 lbs your horse weighs. You can figure your horse's minimum requirement by dividing his weight by 220, then multiplying by 1.3, or you can find the closest weight in the chart below.

Horse’s Weight

Minimum Daily Water Requirement

220 lbs

1.3 gallons

440 lbs

2.6 gallons

660 lbs

3.9 gallons

880 lbs

5.2 gallons

1000 lbs

5.9 gallons

1100 lbs

6.5 gallons

1320 lbs

7.8 gallons

1540 lbs

9.1 gallons

These requirements are increased by dry, windy or warm weather conditions, work or lactation. 

Work Related Fluid Losses
Most of us are aware that working horses lose water in sweat during work but don't always consider that substantial moisture is also lost from the respiratory tract. Unless you weigh your horse before and after work, it may be easy to underestimate the amount of total fluid loss in cool, dry conditions when sweat may evaporate quickly. It's important that you become familiar with signs that may indicate dehydration - elevated heart rate or poor heart rate recovery, elevated respiratory (breathing) rate, dry mucous membranes, skin tenting - and to know what's normal for your horse.

Lactating Mares
Mares with suckling foals are providing fluid for two and their water requirements are two to three times normal maintenance needs. These requirements are also increased by warm, dry or windy conditions.

Monitoring Water Intake
If you use automatic waterers or floats, it's impossible to measure water intake unless they are fitted with a meter. A horse may also become dehydrated if the auto waterer should freeze or malfunction.
If you notice your horses' water intake dropping off, it may be necessary to warm their water either by adding a heater (with a GFI electrical circuit for their protection) or by adding warm or hot water to their tanks or buckets.

The Role of Salt
Sodium and Chloride (NaCl or "salt") play critical roles  in the body's metabolism and are tightly regulated in the blood. Because blood levels are so tightly regulated, standard tests may not indicate a sodium deficiency at the cellular level. When ingested salt levels are low, the body will respond by pulling salt from interstitial fluid into the bloodstream, and by increasing the reabsorption of sodium by the kidneys. (For details on some of the mechanisms involved in sodium regulation, see

Feeding salt on a regular basis at the NRC recommended levels helps ensure an adequate thirst response. After the interstitial fluid has reached an equilibrium, excess sodium, in the absence of disease, will be excreted by the kidneys.

The minimum requirement for sodium in a 1,000 lb horse ranges from 9 grams at maintenance, 16 grams in moderate work, to 37 grams in very heavy work. This is roughly equivalent to a range of from 1 to 3+ ounces of salt per day.  Forages may supply as little as 1 to 2 grams of sodium per day. The best way to making up the sodium deficit is by adding salt directly to the feed. If using a salt block, the amount of sodium it provides should be calculated and the horse's consumption monitored to ensure adequate intake.

 These requirements remain steady except when accounting for sweat loss during work - which can cause large increases. Many "commercial" electrolyte formulas contain high levels of potassium but insufficient sodium and chloride - you should have an understanding of what you actually need before simply adding electrolytes (and never give electrolytes to an already dehydrated horse).

A well hydrated horse will more easily handle the extremes of winter weather and activity. Taking the time to monitor his water intake can set your mind at ease, knowing that you've minimized his risk for cold-weather related colic and respiratory problems.