Over half of mature light-breed horses in the U.S. are obese — an incidence that’s among the highest in the world.

For most of them, the problem is equine metabolic syndrome, which centers around abnormal insulin activity. That, in turn, is driven by people feeding their horses grain-based diets and concentrated carbohydrates. The resulting long-term insulin elevation drives fat storage, which predisposes the horse to laminitis — a painful, and sometimes fatal, breakdown of hoof structures — as well as other problems.

Now, equine veterinarians aren’t just focusing on a horse’s weight loss, they’re measuring the insulin levels that can drive obesity. As consumers and horse stewards, people can do their part by feeding better diets, including good quality hay, instead of relying heavily on tasty grains.

The American Heartworm Society, or AHS, recently released the results of its latest three-year survey of canine heartworm disease.

Although the Gulf Coast and southeastern U.S. still have high case numbers, the updated AHS map shows that canine heartworm disease has expanded to new areas far from these epicenters.

Several reasons are cited for these trends. Populations of infected wildlife, like coyotes, are expanding into urban areas. In addition, dogs are being adopted from heartworm-established areas and relocated to lower-risk locales. Increased storm activity is also fueling subsequent spikes in mosquito numbers. Finally, families moving into high-risk regions may be bringing unprotected pets.

Just remember, canine heartworm disease is nearly always avoidable with the right preventative.

While you were sleeping, your muscles knit themselves back together and your metabolism whirred along. Now, researchers from California are exploring the system behind sleep and human growth hormone — two factors responsible for some of slumber’s most important benefits.

The study looked at how mouse brains reacted to light stimulation. These mammals tend to sleep only a little bit at a time, helping researchers better observe changes in their growth hormone activity through different sleep and wake cycles. Growth hormones juggle a myriad of responsibilities, including muscle and bone construction and fat burning.

Research has previously shown these levels peak during sleep. Thanks to circuity tracing techniques, the team pinpointed how, exactly, the brain coordinates this process.

It starts with a feedback loop that toes the line between wakefulness and sleep. As the growth hormone increases during the latter, it triggers the locus coeruleus [sih-roo-lee-us], an area of the brainstem that encourages alertness. When this activity reaches a breaking point — or should we say waking point — the locus coeruleus begins encouraging drowsiness instead.

In short: Sleep is the driver of growth hormone release, and this hormone, in turn, regulates wakefulness. Getting too little sleep lowers growth hormone levels, but too much of it shifts the brain toward wakefulness. A balance between the two keeps muscle growth and metabolic health in check, and the locus coeruleus’s part points to the possibility of the circuit affecting cognitive functions like attention.

Who are we to argue with another reason to hit the hay?

For dogs with severe hip dysplasia that progresses in spite of conservative treatment, total hip replacement can restore their quality of life.

The hip joint is a classic ball-and-socket structure. The ball at the top of the thigh bone should fit smoothly into a cup-shaped part of the pelvis. In dogs with hip dysplasia, that fit is damaged. So, in a total hip replacement, both sites are removed and replaced with implants.

Postoperative pain management is critical, as is canine rehabilitation, which is a dog’s version of physical therapy. The animal’s activity must be strictly limited for at least three months, including crate confinement when the rest of the family is away.

If pet parents follow their veterinarian’s instructions to a T, their dogs will very likely regain excellent function.

An achy knee or hip joint’s thin or nonexistent cartilage growing back sounds like something a person facing joint-replacement surgery might daydream about.

But researchers led by Stanford University say they have developed a new treatment that could make such a thing possible.

The treatment targets a protein linked to aging. It restored lost knee cartilage in older mice and helped prevent arthritis from developing after serious joint injuries.

In other tests, human cartilage samples taken during knee replacement surgeries showed similar signs of regeneration when given the treatment.

Here’s how it works: 15-PGDH is a “gerozyme,” [JERR-uh-zime] a type of protein that becomes more prevalent with age and contributes to weakening of tissue function throughout the body. The treatment merely blocks the protein.

In past studies, when scientists blocked the protein, older animals gained muscle mass and endurance. When it was artificially increased in young mice, their muscles became weaker and smaller.

Current treatments for osteoarthritis, which slowly breaks down joint cartilage, focus on mitigation and from there, surgery. No medicine slows or stops osteoarthritis.

The researchers say their findings could make it possible to repair damaged knees, ankles, hips and other joints with an injection or an oral medication.

And that would be great news for at least 33 million Americans who find themselves with swollen, painful joints, unable to take the stairs or to stand after sitting without a loud groan.

When it comes to damaged cartilage, most of us would likely welcome repair over replacement.

A recently published case report from the Texas A&M College of Veterinary Medicine & Biomedical Sciences described two dogs that suffered toxicity after accidentally ingesting a livestock feed additive.

Ractopamine is often used as a growth promoter in cattle, pigs and poultry. As a beta-agonist, it can severely damage the heart muscle — as in dogs with access to feed or storage areas.

Both dogs presented with muscle tremors and severe ventricular arrythmias. However, standard treatments for the abnormal cardiac rhythms were ineffective — but beta-blockers did the trick.

This report alerts veterinarians to a novel cause of unexplained ventricular arrhythmias in dogs and details effective treatment. The earlier these dogs are treated, the better their chances are for survival.

Butterflies are beautiful. The colorful patterns on their wings camouflage them and can fool predators into thinking they’re staring into the eyes of larger, more dangerous creatures.

Alas, the lives of these insects are brief, most living just a couple of weeks.

But in the weeping rainforests of Central and South America, a species called Heliconius lives. Its members are the Methuselahs of the butterfly world. Scientists hope they might hold some of the secrets of longevity.

A new study found these butterflies survive, on average, three times longer than their closest relatives, or several months. The longest known lifespan of another subgroup of the species is a whopping 348 days. Compare that to a closely related butterfly species that lives a mere 14 days.

That’s a 25-fold increase in their respective maximum lifespans.

What is more surprising is that another member of the Heliconius species doesn’t show the usual signs of wear and tear that come with aging. Their aging is slowed.

Bottle that and become the world’s next trillionaire.

Researchers believe these insects might provide insight into the biology of healthy aging. What allows them to live so much longer than other butterflies?

If scientists can figure out the mechanism of their longevity, it might provide clues about mammalian aging, including a certain wingless creature that can also fly, in a manner of speaking — humans.

Revealing those aging secrets is undoubtedly many years distant. In the meantime, if you want to live a long life, don’t smoke, eat healthy foods and exercise. And stopping to smell the flowers won’t hurt, either.

Just like their right-handed or left-handed parents, dogs may have a paw preference.

A newly developed test includes four tasks that help determine a dog’s laterality, or pawedness. In one test, a dog is given a KONG toy filled with food, and the technician notes which paw the dog uses to steady it. The paw used to reach for a snack under furniture is also recorded. The technician also notes the paw chosen to take the first step down a staircase, as well as the paw that’s extended when the dog steps off a curb.

Laterality isn’t just a matter of curiosity. Whether a dog is right-pawed or left-pawed may be related to their behavior, emotions and reasoning. For example, left-pawed dogs may be more pessimistic than their right-pawed brethren, while ambidextrous dogs may be more fearful or aggressive.

Alzheimer’s strips its sufferers of their memories and their independence; it robs families of precious time with loved ones who still know them. The disease has no cure. Unsurprisingly, many of us are keen on learning how we can prevent it.

Some brains have already figured that out. According to a new study from researchers in the Netherlands, certain brains are combatting Alzheimer’s by harnessing the protective power of their young cells, helping them survive damage from the disease.

Curiously, the brains of these individuals have all the biological hallmarks associated with Alzheimer’s, but no dementia. They demonstrate something researchers call “cognitive resilience.”

In the study, researchers looked at tissue from a brain bank, analyzing data from samples of brains with Alzheimer’s and without, as well as tissue from brains that showed physical signs of the disease but no dementia. The team focused on an area within the brain’s memory center, where “immature” neurons can still spawn.

Those whose brains demonstrated cognitive resilience — that is, possessed the pathology of Alzheimer’s but no dementia — did not have significantly higher numbers of immature neurons than those with the disease. This, researchers say, could mean that it’s more about how the cells act, rather than how many there are. The immature cells seem to trigger “programs” that help them last through damage, incurring less inflammation and preventing cell death. They might support surrounding tissue and help the brain continue functioning, too.

Further research avenues will look at how these immature neurons talk to other brain cells. For now, it’s heartening to know that some of our brains might know just what to do … even if the rest of us don’t yet.

If you’re a pooch parent, blastomycosis should be on your radar — especially if your dog’s a digger.

Blastomycosis is a fungal infection that most often affects dogs along river valleys in the Midwest as well as in the Southeast. It’s not contagious. Instead, dogs can get infected when they inhale mold spores from the soil.

Signs of blastomycosis — including fever, depression, respiratory problems and weight loss — usually take weeks to months to appear. Infection can spread to other parts of the body, too, with signs referring to the site of infection.

Treatment with antifungal medications generally results in a 50 to 75 percent recovery rate — but only after a dog has been treated for months. As with any infection, the earlier treatment is started, the better.