BIG HEAD DISEASE IN HORSES

Nutritional secondary hyperparathyroidism is a metabolic bone disease --a disease that affects bone metabolism.
It is often called  big head or bran disease.It has also been called Miller's disease.

Causes

• Insufficient calcium intake
• Excess phosphorus intake
• Eating plants which contains oxalates

Nutritional Secondary Hyperparathyroidism is seen mostly in horses grazing exclusively on grasses containing high levels of oxalate that locks up calcium, making it unabsorbable by the horse's intestines.

An excess of phosphorus affects the body stores of calcium in a few ways.

1.High levels of dietary phosphorus reduce calcium absorbtion from the intestine.
2.Excess intake of phosphorus results in the blood phosphate concentration.The phosphorus bind to the calcium in the blood stream,causing the blood calcium concentration to drop.
3.A high blood phosphates concntration also interfers with the conversion of inactive vitamin D to its active form.

Signs

• Enlargement of facial bones
• lameness
• Gait is stiff and stilted
• Physitis in young horses
• Neck pain
• Poor body or coat condition
• lethargy
• Poor growth
• In severe cases tearing of tendon,
• Bone fracture

Treatment and prevention

• Horses grazing oxalate containing pastures and those affected with clinical signs of bighead should be provided with daily calcium supplementation.
• Because NSH is a condition that results from dietary imbalance,treatment  and prevention must focus on correcting the diet
• Mineral and supplement mixtures that will provide the required amount of calcium and phosphorus for horses for a week include 1 kg rock phosphate mixed with 1.5 kg molasses plus 1 kg of a mixture of 1/3 ground limestone and 2/3 dicalcium phosphate mixed with 1.5 kg molasses.
• Calcium supplements
• Supplementation should be continued for 6 months or indefinitely if the horse is to be kept on the offending pasture. Lucerne hay is also high in calcium and should be given in addition to the calcium supplements.
• calcium can be provided through a variety of sources.
• But supplements also contains phosphorus ,such as dicalcium phosphate.
• Alfalfa is a very good natural source of calcium.
• In severe cases, affected horses should be confined to a stall .
• NSAIDS should be used with caution because reducing pain may inspire an increase in the horse's level of activity,which increases the risk of bone damage.
• The horse should not allow for a vigorous exercise even after recovery.

Reference

Lameness
Equine Research
by Christine King and Richard Mansmann

FEEDING FOR IMMUNITY

Allergies, heaves, thrush, insect bite reactions, and hives all can reflect a struggling immune system, as can the more obvious signs of respiratory disease.

Some infections and diseases are beyond your control, but you can influence the outcome by boosting your horse's immune response nutritionally. 

Stress and the Immune System

One of the best things you can do for your horse is pay attention to his stress level and adjust activities accordingly. 
Chronic stress, whether physical or mental, weakens his immune system. When cortisol, the stress hormone, becomes elevated, disease agents that don't normally faze your horse might make him sick--for example, equine herpesvirus (EHV). 

Did you know that your horse might already be infected? This opportunistic organism can remain latent until something (e.g., stress) triggers it, giving it the "opportunity" to cause clinical signs.

Encountering some stressors is inevitable: Horses travel long distances, congregate in strange settings with unfamiliar horses, and are subject to performance stress and other factors. But one of the most common stressors--an empty stomach--is easy to fix. Horses are "trickle feeders" that evolved to roam and graze freely. Not being permitted to graze at will works against a horse's physiology. This is because the horse's stomach, unlike our own, secretes acid continuously, even when empty. Chewing produces saliva, a natural antacid, but it can't help neutralize stomach acid if the horse is left with nothing to chew. Exercising on an empty stomach causes acid to slosh onto the unprotected areas of the stomach's lining, potentially causing ulcers.

Nutrients to Protect Your Horse

Healthy, well-managed pastures supply your horse with many important nutrients, including vitamins E, A (as beta carotene), and C.

 Grasses are also high in omega-3 fatty acids in the proper proportion to omega-6s. 

And if a variety of grasses and clover grow in your pasture, you can expect the protein quality to be good.

While free access to pasture often provides all the nutrients a horse at maintenance requires to remain healthy, many horses rely on hay as their main forage source during winter.

 Hay loses some of its vitamins and omega-3s in storage, so horses consuming only hay for prolonged periods of time (more than three or four months without fresh pasture) might require additional feed supplementation.

 Most horses do well on a fortified commercial feed in recommended amounts. But if your horse exhibits signs of suppressed immune function (e.g., signs of respiratory infections including a runny nose, coughing, and fever; recurrent thrush; bacterial infections; fever; allergic reactions; and general malaise), it's time to boost his diet's nutrient content.

Your horse might need the following vitamins and minerals to fill nutritional gaps and maintain a healthy immune system:

Vitamin E is a powerful antioxidant. Antioxidants protect against disease by neutralizing the damaging free radicals (unstable molecules with an unpaired electron that pull electrons from other molecules) that mental and physical stress produce.

Rhode Island's Department of Fisheries, Animal and Veterinary Sciences, and colleagues examined the impact of vitamin E dosages 15 times the National Research Council's recommended levels on aging horses' immune systems. They found that horses supplemented with vitamin E were more capable of fighting bacteria and produced increased amounts of the antibody immunoglobulin. However, Carey Williams, PhD, associate extension specialist and associate professor at Rutgers University's Department of Animal Science, discovered that just 10 times the recommended dose of vitamin E in otherwise healthy horses interfered with Vitamin A absorption. Gross excess supplementation is not recommended, therefore, even in chronically stressed horses.

"The benefits of vitamin E as an antioxidant and its ability to improve immune function have been known for years--vitamin E impacts several key components of immune function," says Stacy Oke, DVM, MSc, president of Rolling Thunder Scientific, in Ontario, Canada. "There are four different types of vitamin E: α, β, γ, and ? tocopherols. What remains to be known is which types are the most effective."

Many different tocopherols exist in forages and other sources. The form manufacturers most commonly add to commercial feeds and supplements is α- tocopherol. When added in its natural state manufacturers note it as d-α tocopherol in the ingredients, and in its synthetic version they list it as dl-α tocopheryl acetate. Natural vitamin E is more effective as an immune system booster than the manufactured vitamin; however, the synthetic form is more stable and, therefore, has a longer shelf-life.

Vitamin E works parallel to selenium compounds that also serve as antioxidants. University of Kentucky researchers found that a low blood selenium status experienced a delayed immune response to vaccinations. However, selenium can be toxic in high amounts, so horses should only be supplemented if veterinarians document a deficit, and supplement levels should be kept low (below 5 mg/day for an average-sized horse). Vitamin E and selenium are commonly packaged together; evaluate the diet's total selenium content before adding more. For therapeutic doses, it might be better to purchase vitamin E alone.

Vitamin A, in humans, is necessary for normal regeneration of mucosal barriers damaged by infection, and it enhances the function of neutrophils, macrophages, and natural killer cells--three types of white blood cells critical to the immune system. Plants contain beta carotene, which the body uses to produce vitamin A. Beta carotene, vitamin E, and vitamin C work synergistically to reduce inflammation and protect lipids in cell membranes against free radicals' damaging effects.

Boon Chew, PhD, of Washington State University's Department of Animal Science, explains that beta carotene has been reported to modulate the immune system in humans and animals. It increases the ability of specialized white blood cells to damage harmful cells. The resulting inflammation helps eradicate bacterial and viral pathogens and stimulates production of various cytokines, which are messenger cells in the immune system. Beta carotene also stimulates blood neutrophils' phagocytic ability, by which they engulf and eliminate bacteria.

Since most vitamin/mineral supplements and feeds are fortified with vitamin A, it is important to monitor levels before supplementing. The active form of vitamin A (Retinol, retinyl compounds) is toxic at five times the National Research Council's recommended level.

Vitamin C neutralizes free radicals through its ability to donate electrons. The horse's liver normally synthesizes vitamin C in more than adequate amounts and releases and excretes it during periods of prolonged stress. Sarah L. Ralston, VMD, PhD, Dipl. ACVN, associate professor in Rutgers' Department of Animal Science, theorizes that older horses' increased susceptibility to infections might be due to the chronically elevated cortisol secretion associated with pituitary dysfunction (equine Cushing's disease). Ralston finds vitamin C to be an effective supplement in reducing the effects of stressful travel. "We verified that after prolonged transportation stress, oral supplementation (with) vitamin C twice a day was beneficial for the horses the first few days after arrival," she explains.

Omega-3 fatty acids have been shown to reduce inflammation as well as allergic inflammatory response in other species. Researchers at the University of Guelph's Equine Research Centre found evidence that the fatty acid source flaxseed can potentially reduce the allergic inflammatory response in horses susceptible to biting midges (Culicoides). Omega-6 fatty acids can exacerbate inflammatory responses if fed in large amounts, but omega-3s do just the opposite--they help inflammation subside. Omega-6 fatty acids are the predominant form in edible oils such as corn and soybean that are commonly used as calorie supplements. If given in reasonable amounts (less than 2 cups per day to an average-sized horse), they should not pose a threat to a horse's inflammatory system. Some omega-6 activity is beneficial, since inflammation is another way the body combats infections.

High-Quality Protein

At least 8% of a horse's diet should be high-quality total crude protein. A high-quality protein has all the essential amino acids in their proper proportion to allow for adequate body protein synthesis. This enables the immune system to produce antibodies and enzymes and to repair tissues. High-quality protein sources for horses include legumes such as alfalfa, clover, and soybeans. For horses fed lower-quality grass hays, add legume hay pellets or cubes to provide high-quality protein. If you feed a commercial product, check for alfalfa or soybean meal on its list of ingredients.

Other Supporting Nutrients

Some veterinarians and manufacturers have said the following supplements further boost immune support, though these claims haven't been scientifically proven:

• Bioflavonoids These supposedly work with vitamin C to enhance antioxidant capability.
• Coenzyme Q10 Used primarily in humans, nutritionists are just starting to recognize this substance as a potent player on the antioxidant team.
• Water soluble vitamins Thiamine, niacin, panthotenic acid, B-6, riboflavin, and cyanocobalamin work together to support digestion, skin, hooves, hair, blood vessels, protein synthesis, nervous system health, and energy production in all species, and their use and excretion is enhanced during periods of stress. However, in horses only thiamine has been clinically proven to be necessary during periods of prolonged stress. Scientists have not documented deficits of the others in horses.
• Spirulina Blue/green algae reportedly reduces allergy signs and improves respiratory function in other animals

Reference

http://www.thehorse.com/articles/30983/feeding-for-immunity

EQUINE NUTRITION DO'S AND DON'T

DO maximize forage in the diet before adding any grain.

DO feed by weight and not volume.

DO feed hay in a feeder to minimize wastage, which could be up to 50% if hay is fed on the ground.

DO pay attention to pecking order when feeding in a group setting so that a bully doesn’t get the bulk of the food, leaving a submissive horse with almost nothing.
If group-feeding in a pasture setting, DO arrange feed buckets in a circle at least 30 feet apart to give each horse space.

DO put out an extra bucket of grain if feeding a group of four or more so the submissive horse can move to another bucket if needed. The same is true for hay feeders.

DO make changes to a horse’s diet slowly, over a one- to two-week period.
DO feed grain based on current activity level and adjust as activity levels change.

DO feed on a set schedule so as not to upset the horse’s GI tract.

DO feed grain mixes formulated especially for horses. Feeds labeled for horse consumption must be balanced to meet the minimum nutritional requirements for the type of horse listed on the label.


DON’T feed more than 11 pounds of grain per day, or 4-5 pounds of grain per feeding, or the horse’s colic risk increases sixfold.

DON’T worry about too much protein making a horse hot. Only 10% of the horse’s energy comes from protein, so it is a very insignificant source.


DON’T feed supplements unless they are needed.
DO read supplement labels to make sure too much of one nutrient isn’t causing a toxicity in the horse’s diet.

DON’T feed grain just to feed grain. A good-quality forage will meet the dietary needs of most horses that are not in serious work.

Reference

thehorse.com

COMMON NUTRIENT DEFICIENCY IN HORSE

Vitamin E

This potent antioxidant enhances immune function, facilitates cellular respiration, aids DNA synthesis, and improves the absorption and storage of vitamin A, among other roles.

 Fresh grass contains high levels, but these drop once the grass is cut for hay and stored. There are two diseases associated with a vitamin E deficiency: equine motor neuron disease, a rare oxidative disorder that impacts motor neurons in the spinal cord, and equine degenerative myoencephalopathy, a disease characterized by brain stem and spinal cord deterioration. 

Testing is the only way to know for sure if a forage is deficient in E; horses on hay-only diets might need vitamin E supplementation.

Vitamin A is important for vision, bone and muscle growth of young horses, reproduction, healthy skin, and immune response to infection. 

"When green, grass has plenty of carotene, which is the source of vitamin A," 
"But when you start feeding only hay, sometimes horses don't get enough A. Usually A isn't a vitamin of concern because it is added into almost all commercial horse feeds, and if a horse gets enough green grass it's not an issue at all."

Vitamin C is an antioxidant that helps boost the immune system, notes Crandell. Horses' bodies produce vitamin C naturally, but when stressed they might not make enough. 

"We're talking long-term stress," she adds. "Weaning a foal would be an example. In a study looking at blood levels of vitamin C in foals being weaned, the levels dropped during that stressful time."

Horses off their feed due to illness and/or stress can develop B vitamin deficiencies. The equine hindgut (the large intestine, which consists of the cecum and the colon) contains billions of microbes that digest forage and produce B vitamins, which have a variety of functions such as maintaining healthy skin and muscle, promoting cell growth and division, and enhancing the immune and nervous systems.

"If a horse isn't eating enough or if their hindgut is too acidic (due to too much grain and not enough forage) or if the horse has a fever or colic, the hindgut can become out of balance, which compromises production of B vitamins," Crandell explains. "But again, good-quality feeds have B vitamins included in the mix."

"People are feeding magnesium in therapeutic doses to calm a horse, and some say it reduces the thick, cresty neck and the risk of foundering in insulin resistant horses," 

A diet can be salt-deficient, causing metabolic issues, if a horse does not have access to salt. "Forages are low in sodium and chloride (together they make salt), and commercial feeds usually only add less than 0.5% salt to the feed," 

"Calcium and phosphorus need to be balanced in a 1-1 ratio for adult horses; growing horses need 2-1 (ratio, calcium to phosphorus),". "If that ratio is inverted you'll have definite bone problems, such as osteochondritis dissecans--a cartilage disorder characterized by the presence of large flaps of cartilage or loose cartilaginous bodies within a joint--and epiphysitis (inflammation of the ends of the long bones), in your young horse."

References

http://www.thehorse.com/articles/31995/common-nutrient-deficiencies-in-horses

VITAMINS

VITAMINS

Vitamins are tiny organic compounds with a huge impact on the health and well-being of the horse. Certain pro vitamin exists e.g. beta carotene and 7-dehydrocholesterol that do not posses vitamin activity but which can covert to active vitamins by the body.

Each vitamins have different functions with differing demands on reserves.

Fat soluble vitamins

Vitamin A

Source:Green herbage and lesser extend in carrots,yellow maize and legumes seeds

Deficiency : Night blindness,poor growth,excessive lacrimation, reduction in disease resistance and reduced appetite.

Clinical signs:

Excess; Bone fragility and malformations plus some teratogenic effects.

Adults unthriftiness ,poor muscle tone ,ataxia,and loss of hair.

VITAMIN D

Vitamin D provided as vitamin D3,through ultra violet irradiation of 7-dehydrocholesterol in the skin and D2 through exposure of ergosterol,found in plants.

Vitamin D is not believed to be essential for the absorption of calcium in horses.

Source exposure to direct sunlight

Clinical signs skeletal abnormality in foals and osteomalacia in adults.

Decrease in appetite,food intake and impaired mineralization of growing bone.

Excess hypercalcemia, hyperphospatemia,bone resorption,soft tissue calcification,anorexia and poor performance

VITAMIN E

Vitamin E occurs naturally as several isomers of tocopherol and tocotrienol.

Source oils of green plants,wheat germ oil is richest source.

Whether athletic performance is improved by high dietary concentrations of alfa-tocopherol is unproven. But some evidence that exercising animals may benefit from additional supplementation.

Vitamin E is important for immune system in general.

Clinical signs white muscle diseases,depressed immune status,poor performance,reduced fertility and fetal death.

Equine motor neuron disease is believed to be caused by lack of vitamin E.

High dose interferes with absorption or utilization of other fat soluble vitamins.

VITAMIN K

The horse appears to have no need for supplementary sources as the intestinal bacteria seem to synthesis the vitamin k2 which are absorbed in adequate quantities .

Vitamin k status affects bone metabolism as well as blood coagulation.

Water soluble Vitamins

VITAMIN C

Synthesise adequate amount from liver and other tissues from glucose under normal circumstances.

Vitamin C is the key antioxidant in the fluid lining the lungs and that levels are reduced in horses with Recurrent airway obstruction(RAO).

Addtional supplements are required in such circumstances

VITAMIN B1

Synthesized in the intestinal tract and in natural diets.

The richest source is brewer s yeast and baker s yeast

Deficiency

Reduced growth rate,and appetite,leading to anorexia and loss of weight ,ataxia, bradycardia,missing heart beats.

BIOTIN

source is brewer s yeast,oil seed meals,alfalfa meal and maize grain.

Equine hoof defect may be aided by biotin supplementation over many months or years.

Deficiency :poor skin ,poor coat or poor hoof quality .

FOLIC ACID AND VITAMIN B12

Source brewer s yeast, green forages,wheat bran ,oilseeds and whole wheat.

The foal has the greatest need for dietary sources of folic acid and vitamins B12.

Clinical signs Megaloblastic anemia with macrocytosis

Reference

The Equine manual Andrew J.Higgins and Jack R.Snyder 

PREBIOTICS,PROBIOTICS

Prebiotics, probiotics, and the combination of the two (called synbiotics) are nutritional supplements marketed to support and protect the gastrointestinal (GI) system in a variety of mammals, including horses.

 Probiotics are live “good” microorganisms, such as bacteria and yeast. Classic examples of probiotics are the yeast Saccharomyces boulardii and bacteria in the Lactobacillus and Bifobacterium families (e.g., Lactobacillus acidophilus, which is found in some yogurts). In horse supplements, common probiotics include Enterococcus faecium, Lactobacillus acidophilus, Lactobacillus casei, and Lactobacillus plantarum. Millions to billions of colony-forming units (CFUs) are included per serving

In contrast, prebiotics are the foods that feed the probiotics. Examples of prebiotics included in equine supplements include fructooligosaccharides (FOS), xylooligosaccharides (XOS), polydextrose, mannooligosaccharides (MOS), galactooligosaccharides (GOS), pectin, and psyllium. Your horse does not digest these food ingredients. Instead, prebiotics are digested by the “good” microorganisms and probiotics in the horse’s digestive system to increase their numbers or activity.2 When prebiotics and probiotics are supplemented together, the products are referred to as synbiotics, because they work synergistically

 In humans, researchers have studied pre- and probiotics in a variety of disease conditions, including:

 ■ Infectious diarrhea;
 ■ Inflammatory bowel disease (e.g., ulcerative colitis)
 ■ Gastric ulceration;
 ■ Tooth decay/periodontal disease;
 ■ Vaginal infections;
 ■ Skin infections and atopic dermatitis (chronic itchy, scaly skin);
 ■ Weight loss;
 ■ Dysphagia (difficulty swallowing); and
 ■ The treatment of certain cancers.

 In horses, veterinarians primarily recommend prebiotics and probiotics for GI-related concerns, such as diarrhea, to encourage the growth of the good microbes and to minimize the invasion and growth of disease-causing bacteria. 
For example, antibiotic administration, stress, transport, abrupt dietary changes, and Clostridium or Salmonella infections can potentially alter the normal microbe population in a horse’s large intestine. 
Study results have shown that pre- and probiotics aid in digestion and gut health. 
Specifically, probiotics help the horse’s GI tract break down and ferment grass and hay. This fermentation process results in the production of volatile fatty acids that provide a significant energy source to the horse.
 Probiotics also produce B vitamins (such as biotin, which is needed for maintaining healthy hooves) and other nutrients essential to the horse’s overall health. Finally, the “good” intestinal microbes—yeasts, bacteria, protozoa, and fungi—keep the “bad” microbes (such as Salmonella and Clostridium difficile) from overpopulating the intestines and causing diarrhea and illness.

Reference
thehorse.com

HAY SOAKING IN HORSE

Why should I soak my hay?

Respirable dust and mold  

Sub optimal growing and harvesting processes can result in excess dust and/or mold in hay that can cause problems in horses. For example, dust can accumulate in hay grown near dusty roads, and mold can form in hay that has been baled in wet conditions. Dust particles can cause or worsen respiratory problems such as recurrent airway obstruction (RAO).
 Mold can cause digestive upset such as colic and also produces airborne spores that can cause respiratory diseases in horses. Many studies have shown soaking hay can reduce respirable particle concentration by at least 88%. Soaking can also reduce the amount of mold present.

Nutrient content 

Some horse owners soak their hay to reduce the amount of sugars, or nonstructural carbohydrates (NSC), in the forage. Horses that require a low-sugar diet, such as those with laminitis or insulin resistance, might benefit from soaked hay. Soaking Orchardgrass hay for an hour, for instance, can reduce NSC by approximately 40%. If the hay started out with 14% NSC, after soaking the concentration would be below the 12% recommended level for feeding horses with laminitis. In addition to removing sugars, soaking also reduces some minerals. Crude protein, calcium, phosphorus, and magnesium concentrations all decrease with soaking. However, certain horses might benefit from the loss of specific nutrients. For example, researchers at the University of California, Davis, School of Veterinary Medicine recommend that horses with hyperkalemic periodic paralysis (HYPP), a metabolic genetic disease, consume a diet containing less than 1.5% of potassium. Soaking Orchardgrass hay for an hour can reduce potassium concentrations from 2.2% to 1.3%. Soaking this hay for 12 hours can bring the potassium concentration down to 0.65%.

How long should I soak my hay?

The length of time you soak your hay results in significant differences in the reduction of respirable particles and nutrients. Soaking hay for 10 minutes can significantly reduce the number of respirable particles in grass hay, and longer soaking times do not necessarily result in a greater reduction in respirable particles. Soaking length does, however, affect sugar concentrations. Generally, the longer alfalfa or cool-season grass hays are soaked, the greater the decrease in these nutrients. In one study, researchers reported that when they soaked cool-season grass hay for an hour, NSC concentrations decreased from 13.8% to 8.6%. When they soaked the same cool-season grass hay for 12 hours, NSC concentrations decreased from 13.8% to 4.8%. Recommendations for hay soaking times range from 30 minutes to an hour to reduce nutrient concentrations for horses with special needs while still being time-efficient.

Will my horse eat soaked hay?

One study has shown that when soaked hay is the only hay offered, there is no difference in a horse's voluntary intake compared to dry hay. Gradually introducing soaked hay into the diet might not only help avoid digestive upset due to a sudden diet change, but might also help a picky eater acclimate to new forage and maintain a normal feed intake.

What are reasons not to soak?

Although soaked hay has many beneficial effects, there are also reasons not to soak. Soaking hay causes a reduction in NSC concentrations, which is the highest energy component of the hay. For horses that have high nutrient requirements, such as performance horses, growing horses, or lactating mares, nutrient losses due to soaking might be a problem. If appropriate hay is already available, such as low-NSC hay for a horse with laminitis, there is no additional benefit of soaking. The soaking process is time-consuming, and soaked hay cannot be stored for extended periods due to the risk of mold. Furthermore, it is difficult to soak in bulk (round bales) for horses in group housing, and soaking hay in cold winter weather is challenging.

Ashley Fowler, PhD candidate; Tayler Hansen, MS candidate; Brittany Harlow, PhD candidate; and Laura Strasinger, MS candidate, all in UK’s Department of Animal and Food Sciences, provided this information.