As Autumn settles in, the composition of pasture grasses begins to change. The horses are still interested in grazing, and grasses may still largely be green, but the nutrition is not the same.
All grasses have a natural growth cycle and preferred growing conditions during which they will take a few weeks to grow to full height, develop and then drop seed. The stage of active growth and before the grass has set seed is when hay should be cut for peak nutritional value.
After full height is reached and seed begins to form, the caloric value, carbohydrate level and protein in the plant start to drop. Fiber and lignin begin to rise, decreasing digestibility overall. Mineral levels may drop and the minerals present may be less bioavailable because of complexation with fiber. Levels of vitamin E and fat progressively fall. The fat loss is almost exclusively the more fragile omega-3 fats.
For horses being maintained on pasture, the signs of declining nutritional value include:
- Weight loss
- Loss of “bloom” (duller, dry coat)
- Poor hoof quality
- Appearance of hoof abscesses
- Low energy
- Slowed growth in young animals
Horses with poor hind gut function may show a distended abdomen, increased gas and/or loose manure or increased free fluid with manure.
It’s better to start supplemental feeding before you see any of these signs. Offer hay in a covered feeder or in hay bags in shelters. When pasture quality is adequate, they will eat very little or ignore it. A growing interest in hay is a strong indicator pasture nutrition is lacking.
All horses should receive vitamin E, 1000 to 2000 IU/day, preferably in an oil base. Begin supplementing a high omega-3, flax based product at 2 to 6 oz/day. Horses on mature stands of grass should all be supported with an essential amino acid supplement of L-lysine, D,L-methionine and L-threonine. As the pasture ages and begins to lose the bright green color, a concentrated quality protein supplement based on soy and whey should be added if supplemental feeds are not meeting protein requirements. When in doubt about protein and fiber levels, a short pasture analysis can be obtained very inexpensively. Ask your local agricultural extension agent.
If you know when and what to supplement, your pastured horses can keep that Spring glow of health all year long.
Eleanor Kellon, VMD