Nutrition

The effect of hay net design on rate and amount of forage consumed by adult horses

K. Martinson, E. Glunk and W. Weber
Description of the problem

Horses have evolved to consume several small forage-based meals throughout the day, often spending greater than 14.5 hours grazing each day. However, many of today’s horses are housed in boxstalls or drylots, fed two large meals each day, and have limited opportunity to forage. To mimic a more natural feeding pattern many horse owners provide unlimited access to hay. In many cases, this results in obesity because the horses tend to consume hay in excess of their energy requirement. Therefore, it is of interest to identify feeding methods that reduce excess intake, but extend the foraging period beyond a few hours around meal time.
Objective

To investigate the effect of hay net design on the rate and amount of forage consumed by adult horses.
Materials and methods

Eight adult horses in were fed in individual boxstalls. Horses were fed hay off the boxstall floor (control), or from one of three hay nets: large net (6 inch openings), medium net (1.75 inches) and small net (1.0 inch). Horses were acclimated to their assigned treatment for 2 days, followed by 3 days of data collection, and a wash-out period of 2 days. Horses had access to hay inside the nets for two 4hour periods: 7:00 to 11:00 am and 4:00 to 8:00 pm each day. Throughout the trial, grass hay was fed at 1% body weight twice each day. To determine forage consumption rate, stopwatches were started once horses began eating, and stopped once horses either finished all offered hay, were no longer interested in eating, or the 4 hour time period had expired. All refuse hay was collected and weighed. Total forage consumed was calculated by subtracting amount of refuse from hay offered.
Results

Mean consumption rates were 3.3, 2.9, 2.4, and 1.9 pounds per hour for the control, large net, medium net and small net respectively. Horses were able to consume all hay from the control and large during the 4hour feeding period, but not all horses finished the hay meal when fed from the medium and small nets. Mean percentage of offered hay consumed was 95, 95, 89 and 72% for the control, large net, medium net and small net, respectively. A second study revealed that horse feeding from the medium net took just over 5 hours to consume the hay meal, while horses eating from the small nets took 6.5 hours to consume the meal. Both the control and large net resulted in consumption times of 3.2 and 3.4 hours, respectively.
Benefits to the equine industry

These results demonstrate that the small or medium nets were effective in decreasing rate and amount of forage consumed and increasing the total time of forage consumption by adult horses. If small or medium hay nets were used for twice daily feedings in a boxstall setting, the anticipated amount of time horses would spend foraging would be 10 to 13 hours each day; more closely mimicking a horse’s natural grazing behavior. Small and medium hay nets represent simple and affordable management tools for extending foraging time when meal feeding horses. However, use of the small and medium hay nets is not likely practical for all horses and it does take time (usually 4 to 5 feedings) for horses to acclimate to feeding from the nets.

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Steaming’s Effect Horse Hay

Steaming’s Effect Horse Hay Studied
By Casie Bazay, BS, NBCAAM

Soaking hay in water is a common practice used to reduce dust and non-structural carbohydrate (NSC) levels for horses with respiratory or metabolic conditions. But soaking can leach essential nutrients, such as phosphorus and magnesium, from hay and be labor-intensive.

In the last few years hay steaming has gained popularity as a soaking alternative, but how does it compare to soaking? University of Minnesota researchers, who recently studied soaking’s effect on hay, set out to answer that question.

“We had been receiving many questions from horse owners and professionals about the effectiveness of steaming on forage quality and no data (that we could find) existed,” explained Krishona Martinson, PhD, assistant professor in the Department of Animal Science.

The group set out to evaluate steaming’s effects on four factors:

Nutritive values, including dry mater (DM), crude protein, water soluble carbohydrates (WSC), ethanol soluble carbohydrates (ESC), calcium, and phosphorus among others;
Mold concentrations;
Airborne dust particles (TSP, or total suspended particulates); and
Horses’ voluntary dry matter (DM) intake.
Two hay producers harvested two lots of alfalfa-orchardgrass small-square bales at different moisture levels. The researchers randomly selected 40 bales from each lot and took core samples from 26 bales in each lot to analyze.

Then, the team classified the bales as having either low mold (LM) or medium mold (MM) concentrations. Researchers then selected 10 LM and 10 MM bales to steam for 90 minutes using The Professional Hay Steamer by Happy Horse Products, Ltd. Samples from the steamed bales were also analyzed.

Finally, the team fed six adult horses steamed and un-steamed LM and MM hay in a 10-day crossover design to measure the animals’ hay intake. Horses received both steamed and un-steamed hay from one lot simultaneously for a 2-hour period each day.

The team concluded that steaming hay:

Reduced the DM concentration for LM and MM hay, by 14 and 11%, respectively;
Reduced WSC by 12% and ESC by 31% in MM hay, but had no effect on WSC or ESC in LM hay;
Did not affect other measured nutritive values in MM or LM hay;
Reduced mold concentrations in by 99% in LM hay and 91% in MM hay; and
Considerably reduced TSP in MM hay (by 55%) but did not affect TSP in LM hay.
Additionally, the researchers found that steaming did not increase horses’ MM hay intake, but horses did consume more LM hay after steaming. Martinson explained this could be because steaming kills the mold, but doesn’t remove it: “If mold had an unpalatable flavor …. its mere presence, whether dead or alive, likely affected forage intake rates.”

Martinson said the main benefit of steaming appears to be the increase in consumption of good-quality hay. She added that “steamed hay might be useful for horses recovering from surgery, malnourished horses, older horses with poor teeth, or picky eaters.”

Martinson said soaking is likely “more affordable and a better solution when managing horses with respiratory issues or when the goal is leaching out NSC (for horse with laminitis, EMS, obesity) or potassium (for horses with HYPP).”

The study, “Effect of hay steaming on forage nutritive value and dry matter intake by horses,” was published in the December issue of Journal of Animal Science. 

Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.

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“Nutritional Management of Insulin Resistance in Horses”

Nutritional Management of Insulin Resistance in Horses

By Alexandra Beckstett, The Horse

Managing Editor December 9, 2013 8:00

When it comes to caring for insulin-resistant (IR) horses, diet plays a very important role in managing insulin levels and preventing associated diseases such laminitis. Insulin resistance and hyperinsulinemia are key features of equine metabolic syndrome (EMS) and can also occur in horses with pituitary pars intermedia dysfunction (or equine Cushing’s disease). These animals often need to lose weight and consume fewer carbs.

To that end, Ray Geor, BVSc, PhD, Dipl. ACVIM, a professor and researcher at Michigan State University’s department of large animal clinical sciences, shared best feeding practices for IR horses at the 2013 International Equine Conference on Laminitis and Diseases of the Foot, held Nov. 1-3 in West Palm Beach, Fla. He first discussed weight loss, then carbohydrate consumption.

Managing Obesity

Geor explained that dietary restriction and exercise are two key components to curbing obesity in IR horses. “Dietary restriction is not rocket science,” he said. “But it requires owner/trainer compliance and patience and sticking to the program (to be successful). Diet changes are likely a lifelong pursuit, especially for horses with EMS that are easy keepers and have a tendency to become obese.”

Geor recommended owners of affected horses institute a weight loss program with the goal of improving the animal’s metabolism to reduce his risk of developing associated laminitis. He offered the following guidelines for developing a program:

Base your horse’s diet on forage or a forage substitute, and eliminate grain and calorie-dense feeds (e.g., sweet feeds) if possible. – Feed a lower-quality, low-energy forage, such as late-maturity hay, at between 60 and 80% of your horse’s daily energy requirements based on his body weight.
When feeding a low-quality forage, add a ration balancer to help your horse meet his vitamin E, copper, zinc, and other requirements. “Alternatively, forage-based, low-calorie feeds that contain added vitamins and minerals are now available commercially,” Geor said. “This type of feed offers convenience and may be used as a substitute for hay or fed as a component of the ration along with hay.”
Although all weight loss programs need to be individually tailored, as a general guide start by restricting your horse’s daily dry matter intake (DMI) to 1.5% of his body weight in total feed. The rate of weight loss will vary between horses but in general at least six to eight weeks of dietary restriction is needed for noticeable weight loss to occur, Geor said. If your horse’s weight loss response is less than desired, you might need to restrict his DMI to 1.25% body weight. If he still doesn’t lose weight after another six to eight weeks, you can restrict his DMI even further to 1% body weight, but Geor recommended never feeding lower amounts than that for health and behavior reasons. “Hay feeders and slow feeders (e.g., hay nets with multiple small holes) are one way to extend your horse’s hay supply if you’re not feeding much,” he said.
Restrict or eliminate pasture grazing using a grazing muzzle or a drylot for turnout. “It should be noted that simply restricting the time allowed for grazing may not be an effective strategy for weight loss,” Geor cautioned. “Ponies have been observed to consume up to 1% of body weight within three hours of pasture turnout.”
And as with any diet changes, make feed changes gradually and avoiding withholding food from your horse for long periods. Divide rations into three to four small meals, and do not bed a dieting horse on straw or shavings to reduce the risk of him eating them and potentially suffering an impaction, Geor said.
Geor encouraged owners to use a number of simple tools to monitor their horses’ weight loss, including body condition scoring and measurements of girth and abdominal (‘belly’) circumference. “Body condition score is not always a sensitive indicator of weight loss,” he added. “However, girth and belly circumference measurements will decrease with weight loss, and I recommend recording these measurements at three- to four-week intervals.”

But once your horse meets his targeted weight and condition, you can’t just stop there: “Develop and continually update an appropriate weight maintenance program,” Geor said. “It should include monthly assessment of body weight and BCS to ensure that the feeding program is appropriate for the current level of physical activity and other environmental influences on energy requirements.”

Controlling Carbohydrates

Veterinarians and researchers have long associated laminitis with increased nonstructural carbohydrate (NSC) intake—especially in pastured horses. And because NSCs can contribute to exaggerated insulin responses, it’s particularly important to restrict their intake in IR horses.

Geor offered suggestions for controlling NSC intake:

Feed a forage-based diet with a low NSC content (less than 12%). “Soaking hay can help lower NSC levels, but it’s not a panacea,” he said.
Eliminate grain and sweet feed (both high in NSCs) from the diet.
Restrict or eliminate pasture access. At certain times of year (e.g., during spring and early summer growth periods, after summer or fall rains, or after drought or frost) pasture forages’ NSC content is quite high, so Geor advised keeping IR horses off pasture during these periods to reduce the risk of developing laminitis. He said a grazing muzzle might be the best way to safely restrict grass consumption (studies show it can decrease pasture intake by about 80%), as simply providing a smaller space to graze can lead to an overgrazed area, which will still have high NSC content due to stress. Also, “beware the ‘Hoover’ pony,” Geor said. “They can adapt and consume around 40% of their daily DMI in just two to three hours.”
In conclusion, Geor said correcting obesity and restricting NSCs are not a cure for insulin resistance but these strategies can help to prevent laminitis in affected horses.

Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.

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The Aged Horse: Immune System and Nutrition

From the Equine Disease Quarterly, University of KY

The Importance of Nutrition in Enhancing Immunity in the Aging Horse

Over the past century, improvements in health care and advancements in biology, chemistry and medicine have extended the average lifespan of humans and companion animals, including horses. However, we are now facing new challenges with the paradox of an older population with increased longevity, while confronted with the potential for many years of poor health. A better understanding of the mechanisms leading to a decline in physiologic function with age would provide new predictive biomarkers and potential therapeutic targets.It has been well-documented that the aged, including horses, have increased susceptibility to and prolonged recovery from infectious diseases, poor responses to vaccination, and increased incidence of various cancers. Furthermore, it is now accepted that chronic inflammation (inflamm-aging) is a major underlying condition of many age-related diseases, such as atherosclerosis, arthritis, cancer, diabetes, osteoporosis, dementia, vascular diseases, obesity and metabolic syndrome.In anti-aging research, much attention is focused on nutritional interventions as practical, cost-effective approaches to mitigating this agerelated breakdown in immune function. These natural dietary compounds found in a variety of fruits, vegetables, nuts and seeds are promising candidates in helping to combat the effects of aging. They possess broad biological activities: anti-oxidative, anti-inflammatory, detoxification, regulating signaling pathway, and modulation of enzyme activities (see Table 1).Since aged horses (>20 years) have increased levels of inflammation, and treatment with longterm use of non-steroidal anti-inflammatory drugs (NSAIDs) such as flunixin meglumine and phenylbutazone can pose health problems, we are interested in nutritional interventions to counteract this inflamm-aging process.Flavonoid (quercetin) and polyphenolic compounds (curcuminoids, resveratrol, pterostilbene and hydroxypterostilbene) were compared to phenylbutazone and flunixin meglumine to determine differences in equine cytokine production in cell culture. White blood cells from aged horses were isolated and incubated overnight with each compound or NSAID at multiple concentrations. Inflammation production was measured when cells were stimulated.At varying doses (measured in micromolar units [μM]), each of the compounds and NSAIDs significantly reduced cellular inflammation: curcuminoids (20 μM), hydroxypterostilbene (40 μM), pterostilbene (80 μM), quercetin (160 μM), resveratrol (160 μM), flunixin meglumine (40 μM) and phenylbutazone (>320 μM). Interestingly, curcuminoids at a concentration of 20 μM reduced inflammation to the same level as higher doses of flunixin meglumine (40 μM) and phenylbutazone (>320 μM). All natural compounds outperformed phenylbutazone by being effective at lower doses.This preliminary research has led into two studies using aged horses to determine: 1) if a relationship exists between circulating vitamin and fatty acid levels to systemic inflammation and muscle mass, and 2) if anti-inflammatory supplementation affects immune responses to vaccination. These are preliminary steps to identify effective nutritional intervention regimens to improve function of the immune system in the aged horse.

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