Equusの Spring 2020 の目次

RESEARCH LINKS DIET AND BEHAVIOR A University of Glasgow study confirms something that owners of feisty ponies have long observed—diets high in starch can contribute to “spookier” behavior. To investigate possible correlations between behavior and the gut micro-biome, the researchers used 10 untrained ponies. For two weeks, half of the ponies received a high-starch ration, and half were fed a high-fiber diet. The rations were then switched for an additional two-week period. At the end of each 14-day feeding period, the researchers collected fecal samples from each pony and extracted DNA data from the bacteria present. They also performed two tests to gauge how the ponies reacted to various stimuli. In the first test, an unfamiliar person stood passively in a small area with each pony. For the second test,…

Our emotions, taken together with the way we respond to these emotions, create what is often called “character.” More than any other factor, character determines the success or failure of your relationship with horses. “Whoa,” you may think, “a dissertation on character is a long way from tips on how good riders get good.” But believe me, it is the best-kept secret of riding success. Why? We riders experience the same wide range of emotions as all other human athletes—but with a difference: We aren’t alone. The horse we ride also has emotion. Plus, our emotions affect him, and his emotions affect us. When a baseball player is nervous as he steps up to the plate, his baseball bat doesn’t sense his anxiety and start shaking, too! But a horse…

Photographs and videos can add more power to contracts and enhance the protections they provide. For example, a lease contract can include the photograph of the horse at the beginning of the agreement so there aren’t any questions about whether the person is managing the horse properly. Often photos or video documentation are made part of an agreement to reduce the amount of interpretation required if issues arise. Include photographs and videos so the level or condition of the horse is clear and make sure this documentation is referenced correctly in the contract. With proper visual documentation, there is less chance that issues will need to be decided by a mediator or through a lawsuit.…

It’s easy to go on autopilot when it comes to your horse’s vaccination schedule. Spring rolls around and you simply schedule the same vaccines he received last year. Or may be your veterinarian offers a health plan that includes vaccinations in its regular spring-checkup package. Either approach usually works just fine. After all, good habits are the foundation of any effective health-care regimen. Nonetheless, it’s wise to periodically take a step back to reassess the variables in your horse’s vaccination program—his health, lifestyle, the products available—and adjust accordingly. Whether it’s giving a different set of vaccines or changing the timing of the actual injections, many components of a vaccination program can be adjusted for optimum results. Here are the four primary factors to consider when reviewing your horse’s vaccination protocol…

You might think your horse’s advancing age may be reason to alter his vaccination protocol, but if he’s on an appropriate program to begin with, advancing years alone don’t necessitate a change. Likewise, there’s no truth to the notion that older horses need fewer vaccines because their immune systems have already “learned” to fight various diseases. In fact, research has shown just the opposite—a horse’s immune system may “forget” what it knows as the horse ages, a natural event called immunosenescence. In other words, more frequent vaccination might be a better plan. There’s no truth to the notion that older horses need fewer vaccinations. Why not “pull a titer” to see if an older horse still has sufficient antibodies against a given disease? Great question. Although previously titers were not…

Gene: The unit of inheritance. A gene is a sequence of molecules on the DNA strand that encodes the synthesis of a protein. In Sewall Wright and Kleberg’s time this was not known; geneticists of that era conceptualized genes as discrete particles, often pictured as beads. Genotype or Genome: The genes of an individual (not visible to ordinary observation) that determine traits that can be observed; see phenotype. Gene Pool: The stock of genes carried by a breeding population, including all possible allelic variants that can be found in that population. Note the difference between the genome (possessed by the individual) and the gene pool (representing the whole population). Phenotype: All the factors about an individual that are observed or measured. The term covers an individual horse’s conformation, developmental process,…

Chicaro (1923)—Sired by the imported Thoroughbred *Chicle, Chicaro was the first Thoroughbred purchased by Bob Kleberg as an outcross sire. Before being acquired by the King Ranch, Chicaro had already sired the nearly unbeatable short-track horse Flying Bob (see “Quarter Horses Adapt to a New Century,” EQUUS 495) along with a dozen other good mares and stallions bred by Louisiana and Texas short-horse fanciers. After arriving at the King Ranch in 1934, Chicaro was put to cover both pedigreed Thoroughbreds and mares of Quarter Horse type who had been sired by Little Joe, Yellow Jacket, Ace of Hearts, John Dial, Old Sorrel and the Old Sorrel son Solis. Chicaro’s own dam is the Thoroughbred Wendy by Peter Pan of the Himyar line; her tail-female goes to Bonnie Scotland and the…

The best place for a horse to recover after strenuous exercise is with a group of companions rather than alone in a box stall, according to a new study from Sweden. Researchers at the Swedish University of Agricultural Sciences in Uppsala investigated the effects of housing on post-exercise recovery in eight mature trotting horses. The horses were kept in either small herds in a group housing system or alone in box stalls for 21 days, then switched to the other housing method. On days 7 and 14 of each study period, the horses underwent a race-like exercise test. Researchers collected blood before, during and several times after exercise. The data showed that after intense exercise, horses kept alone in box stalls ate less than horses living outdoors in groups. In…

The woman’s voice on the other end of the line was calm and measured but I could tell this was a difficult discussion for her to have. She had left me a voicemail, stating that her beloved horse was now lame after being leased to someone for only a week. A potentially career-ending injury had occurred during that time. The veterinary bills were piling up, and her horse was now on stall rest for an indefinite period. The owner had never received any money from the person leasing the horse and she wanted to know her legal recourse. After she provided some details, I asked her if she had a contract. She hesitated, finally admitting that she did but that the person leasing the horse hadn’t signed it yet. When…

The core vaccines for horses—those recommended for every horse—protect against the following diseases: • eastern/western equine encephalomyelitis—brain and spinal cord inflammation caused by alphaviruses that are usually transmitted by mosquitos. Two forms that most commonly affect horses are eastern equine encephalomyelitis (EEE), which is fatal in about 90 percent of cases, and western equine encephalomyelitis (WEE), which has a mortality rate of about 50 percent. • rabies—a fatal viral disease of the central nervous system. Rabies is most often spread through saliva from the bite of an infected animal. In the United States, reservoirs of the virus exist in raccoon, skunk, fox and bat populations. Rabies is a public health threat, which means that veterinarians are required to report all cases. • tetanus—paralytic disease characterized by spasms of the voluntary…

Upon his father’s death in 1932, Robert J. Kleberg, Jr. became manager of King Ranch and was named its president three years later when it was incorporated. For the next 50 years, “Mr. Bob” was the prime mover behind King Ranch horse and cattle breeding programs and he deserves major credit for designing a scientific and highly effective breeding system. Gritty, persistent, indomitable and highly knowledgeable, Kleberg famously summed up his philosophy when he told his daughter, “You must have a dream first. Then work like hell to make it come true.” The King Ranch program contains valuable lessons for anyone interested in breeding horses, whether their operation is large or small. As King Ranch enterprises grew to become multi national after 1940, Bob Kleberg’s nephew Richard Kleberg, Jr. (“Mr.…

This chart, which depicts the inheritance of recessive alleles, is very useful if you want to get a concise idea of why matings with known carriers of genetic diseases are best avoided. A short list of genetic diseases of horses (across all breeds) that are inherited as recessives and expressed only when the foal inherits two copies, “aa,” of the recessive alleles: HYPP (hyperkalemic periodic paralysis), HERDA (hereditary equine regional dermal asthenia), LFS (lavendar foal syndrome), CA (cerebellar abiotrophy), GBAD (glycogen branching enzyme deficiency), SCID (severe combined immunodeficiency) and JEB (junctional epider-molysis bullosa). However, any deleterious phenotypic trait—such as thin shelly hoof walls, weak ankles, or retained placenta—is best regarded as charting exactly the same as recessive genetic diseases. Avoidance should be the rule even when the deleterious trait may…

Offered at stud from 1910 on by Ott Adams, Little Joe became an important part of King Ranch breeding when Bob Kleberg noticed that mares by him crossed very well on Old Sorrel. Little Joe (1905) is by Traveler out of Jenny. Jenny is by Sykes Rondo, out of May Mangum by Anthony. Jenny is a double descendant of Old Billy (1860) and the legendary Shiloh (1844). (See “Change on the Horizon,” EQUUS 493, for my analysis of Traveler’s likely pedigree and phenotype.) Almost certainly of Mountain Horse descent, Traveler threw smooth conformation, speed and loud (rabicano) coloration. Little Joe himself was brown with minimal white but many of his descendants resembled Traveler in manifesting white hairs at the top of the tail, high white on the legs, wide blazes…

The King Ranch used covers by a number of stallions from the U.S. Army Remount Service. The availability of these high-quality stallions served to boost the quality of horses on thousands of farms and ranches in the western half of the country, not just the King Ranch. The list used by the Klebergs included American Flag, Lion D’Or, *Naughty Boy II, and Right Royal (see “Quarter Horses Adapt to a New Century,” EQUUS 495). The Ranch also owned many Thoroughbred sires; Martin’s Best and Chicaro are the most important of these but the list also includes John Dial, Brillante, Boojum, Cientifico, Sudden Change, Bim Bam, Moso, Remolino, Don Manners, One Tenth, Beau Max, Destino, On The Mark, Poised, High Gun, and Navigator. As if these were not enough to provide…

MANAGEMENT The implications of excessive urination Q: My 11-year-old Quarter Horse gelding has always been healthy, but lately I’ve noticed that he seems to be urinating more than usual. I don’t actually see him emptying his bladder more often, but I do find that I’m removing more wet bedding from his stall than normal. Is this something to be concerned about? He seems otherwise fine. Name withheld by request A: Excess urination is called polyuria (PU). For a horse with PU to maintain a normal hydration state, he must also have polydipsia (PD), which is increased drinking. PU/PD can be a consequence of diet, a behavior problem or a sign of disease. The kidneys filter waste products from the blood and eliminate these wastes in urine. They also regulate the…

Birds nesting in your barn present a dilemma. Yes, they can be noisy, destructive and messy, but birds help keep the insect population under control and contribute to a balanced ecosystem around your farm. Before deciding whether to try to evict birds from your barn, do a bit of research on the species. Swallows, for instance, eat so many insects they are worth the mess they may make. And if you have a barn owl, do whatever you can to encourage him to stay and hunt mice. Some species of birds may be protected by federal or local statutes, particularly when they are nesting. The most effective tactic for thwarting unwanted birds is to disturb their nests as they are building them. If you notice birds coming in and out…

A study from Spain suggests that parasite-eating fungi may be used to prolong the efficacy of deworming treatments for horses. The life cycles of many parasites that infect horses, including small strongyles, rely on pastures. When parasite eggs are expelled with manure, a reservoir of larvae develop in the soil and then re-infect horses as they graze. One way to break this cycle is to remove horses from a pasture until the parasites die off, but some can persist for long periods, which makes this method less reliable. Working at the University of Santiago de Compostela, researchers dewormed 22 mature horses with ivermectin, then divided them into three groups. The first group was kept continually on the same pastures and fed a standard pelleted feed. The second group also received…

In retrospect, I know that I did many things wrong on my pack trip into California’s Sierra Nevada mountains. Initially, all was well as I rode my horse, leading a two-pack string, while my boss and a friend hiked behind me. But then I made a basic and irreversible mistake: I didn’t hold onto or securely tie my horses when I dismounted to confer with my boss. My horses are smart and trained to ground tie, so I wasn’t too worried when they started to walk down the trail away from us. I said “Whoa, boys,” and began to follow. In response, they defiantly picked up a trot. I clearly remember my feeling of disbelief as I watched the dust kicked up from their hooves. Then came a sinking realization…

The “risk-based” vaccines—recommended for horses only if their health, lifestyle or location puts them at increased risk—protect against the following diseases: • anthrax—a potentially fatal systemic infection caused by the spore-forming bacterium Bacillus anthracis, which is found in the soil in some regions. • botulism—neuro-poisoning caused by the toxin secreted by Clostridium botulinum bacteria, which can contaminate feed, water or wounds. Horses may die from respiratory failure or complications of recumbency. Shaker foal syndrome is another form of the disease. • equine influenza—a common, acute viral infection involving the respiratory tract. The virus mutates easily and immunity is short-lived, making horses susceptible to influenza even after recovery. • equine viral arteritis—a highly contagious disease that causes mild respiratory signs in most horses. EVA can trigger abortion in broodmares. Breeding stallions…

Several important insights may be gleaned from this table. The degree of relatedness, expressed as a percentage, increases with the number of generations over which inbreeding continues to be carried out. The rate of increase is higher when matings occur between more closely related individuals—it is higher between parent and offspring than between uncles and nieces. All inbreeding plans ultimately lead to fixation of recessive alleles. In the “Plan A” breeding scheme, a single male is mated to two half-sisters in each generation. Under “Plan B,” a single male is mated to many half-sisters in each generation. This table shows the degree of relatedness that results from different breeding plans, which is a measure of the number of identical alleles found in related individuals. Degree of relatedness is vastly different…

A sketch of Old Sorrel surrounded by various imaginary broodmares, some of Thoroughbred type, others of Billy type, still others more or less mixed. They represent the variety of mares actually brought to Old Sorrel between about 1921 and his last foal crop, sired in 1943 (Old Sorrel covered a total of about 70 different mares in his lifetime, so this diagram is a simplification). I have assigned each mare a letter which can be thought of as a “mare family” or “mare bloodline.” Pink circles in the next part of the chart represent mares and fillies while blue squares represent colts. Mares A, B, C, D, E, and F may be covered more than once so that they bear one, two, or three foals, ideally over a short span…

Bold Venture (1933) is by St. Germans of the Isinglass sire-line, out of Possible by Ultimus, a sire-line descendant of Himyar, with tail female tracing to the elegant Glencoe and the redoubtable and durable Sir Archy. Bold Venture is the sire of 1946 Triple Crown winner Assault (out of Igual, a mare bred by Bob Kleberg from Incandescent by *Chicle) as well as King Ranch bred 1950 Kentucky Derby and Belmont winner Middleground. On the Quarter Horse side, Bold Venture also sired several mares essential to Kleberg’s breeding program. Miss Princess, a.k.a. “Woven Web,” foaled in 1943, is one of Bold Venture’s daughters who had a performance rather than a breeding career. The photo demonstrates that very fast horses do not have to be tall. Miss Princess represents one of…

Was King Ranch performance testing meaningful? Here are a few photos of the Klebergs and ranch foreman Lauro Cavazos, Sr., who along with many other Kineño employees tested King Ranch stallions and mares and rated them for inclusion in the Quarter Horse herd. Bred for aptitude to the work, the horses did not take long to learn their jobs, and when they were fully mature at six years of age, the Klebergs confronted them with real-world working conditions that demanded all a good horse can give. Denhardt reports that Bob and Dick Kleberg and Cavazos were a working team and maintained a long-running friendly rivalry to see whose horse could outperform all others. These photos bring out an old argument between those who ride “English” and those who ride “Western,”…