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The endometrium is the inner epithelial layer, along with its mucous membrane, of the mammalian uterus. It has a basal layer and a functional layer: the basal layer contains stem cells which regenerate the functional layer. The functional layer thickens and then is shed during menstruation in humans and some other mammals, including other apes, Old World monkeys, some species of bat, the elephant shrew and the Cairo spiny mouse. In most other mammals, the endometrium is reabsorbed in the estrous cycle. During pregnancy, the glands and blood vessels in the endometrium further increase in size and number. Vascular spaces fuse and become interconnected, forming the placenta, which supplies oxygen and nutrition to the embryo and fetus. The speculated presence of an endometrial microbiota has been argued against.
Zebras are African equines with distinctive black-and-white striped coats. There are three living species: Grévy's zebra, the plains zebra, and the mountain zebra. Zebras share the genus Equus with horses and asses, the three groups being the only living members of the family Equidae. Zebra stripes come in different patterns, unique to each individual. Several theories have been proposed for the function of these patterns, with most evidence supporting them as a deterrent for biting flies. Zebras inhabit eastern and southern Africa and can be found in a variety of habitats such as savannahs, grasslands, woodlands, shrublands, and mountainous areas.
The hoof is the tip of a toe of an ungulate mammal, which is covered and strengthened with a thick and horny keratin covering. Artiodactyls are even-toed ungulates, species whose feet have an even number of digits; the ruminants with two digits are the most numerous, e.g. giraffe, deer, bison, cattle, goat, pigs, and sheep. The feet of perissodactyl mammals have an odd number of toes, e.g. the horse, the rhinoceros, and the tapir. Although hooves are limb structures primarily found in placental mammals, hadrosaurs such as Edmontosaurus possessed hoofed forelimbs. The marsupial Chaeropus also had hooves.
Equus is a genus of mammals in the family Equidae, which includes horses, asses, and zebras. Within the Equidae, Equus is the only recognized extant genus, comprising seven living species. Like Equidae more broadly, Equus has numerous extinct species known only from fossils. The genus originated in North America and dispersed into the Old World and South America during the Early and Middle Pleistocene. Equines are odd-toed ungulates with slender legs, long heads, relatively long necks, manes, and long tails. All species are herbivorous, and mostly grazers, with simpler digestive systems than ruminants but able to subsist on lower-quality vegetation.
A foal is an equine up to one year old; this term is used mainly for horses, but can be used for donkeys. More specific terms are colt for a male foal and filly for a female foal, and are used until the horse is three or four. When the foal is nursing from its dam (mother), it may also be called a "suckling". After it has been weaned from its dam, it may be called a "weanling". When a mare is pregnant, she is said to be "in foal". When the mare gives birth, she is "foaling", and the impending birth is usually stated as "to foal". A newborn horse is "foaled".
Lanugo is very thin, soft, usually unpigmented hair that is sometimes found on the body of a fetus or newborn. It is the first hair to be produced by the fetal hair follicles, and it usually appears around sixteen weeks of gestation and is abundant by week twenty. It is normally shed before birth, around seven or eight months of gestation, but is sometimes present at birth. It disappears on its own within a few weeks.
In human anatomy, the eponychium is the thickened layer of skin at the base of the fingernails and toenails. It can also be called the medial or proximal nail fold. The eponychium differs from the cuticle; the eponychium comprises live skin cells whilst the cuticle is dead skin cells. Its function is to protect the area between the nail and epidermis from exposure to bacteria. The vascularization pattern is similar to that of perionychium.
Laminitis is a inflammation of laminae that affects the feet of ungulates and is found mostly in horses and cattle. Clinical signs include foot tenderness progressing to inability to walk, increased digital pulses, and increased temperature in the hooves. There is also swelling in foot in some cases.Severe cases with outwardly visible clinical signs are known by the colloquial term founder, and progression of the disease will lead to perforation of the coffin bone through the sole of the hoof or being unable to stand up, requiring euthanasia.
Grévy's zebra, also known as the imperial zebra, is the largest living wild equid and the most threatened of the three species of zebra, the other two being the plains zebra and the mountain zebra. Named after Jules Grévy, it is found in parts of Kenya and Ethiopia. Superficially, Grévy's zebras' physical features can help to identify it from the other zebra species; their overall appearance is slightly closer to that of a mule, compared to the more "equine" (horse) appearance of the plains and mountain zebras. Compared to other zebra species, Grévy's are the tallest; they have mule-like, larger ears, and have the tightest stripes of all zebras. They have distinctively erect manes, and more slender snouts.
A horse hoof is the lower extremity of each leg of a horse, the part that makes contact with the ground and carries the weight of the animal. It is both hard and flexible. It is a complex structure surrounding the distal phalanx of the 3rd digit of each of the four limbs, which is covered by soft tissue and keratinised (cornified) matter.
Cerebellar abiotrophy (CA), also called cerebellar cortical abiotrophy (CCA), is a genetic neurological disease in animals, best known to affect certain breeds of horses, dogs and cats. It can also develop in humans. It develops when the neurons known as Purkinje cells, located in the cerebellum of the brain, begin to die off. These cells affect balance and coordination. They have a critical role to play in the brain. The Purkinje layer allows communication between the granular and molecular cortical layers in the cerebellum. Put simply, without Purkinje cells, an animal loses its sense of space and distance, making balance and coordination difficult. People with damage to the cerebellum can experience symptoms like unsteady gait, poor muscle control, and trouble speaking or swallowing.
Decidualization is a process that results in significant changes to cells of the endometrium in preparation for, and during, pregnancy. This includes morphological and functional changes to endometrial stromal cells (ESCs), the presence of decidual white blood cells (leukocytes), and vascular changes to maternal arteries. The sum of these changes results in the endometrium changing into a structure called the decidua. In humans, the decidua is shed during childbirth.
Equine viral arteritis (EVA) is a disease of horses caused by a virus of the species Alphaarterivirus equid, an RNA virus. It is the only species in the genus Alphaarterivirus, and that is the only genus in the Equarterivirinae subfamily. The virus which causes EVA was first isolated in 1953, but the disease has afflicted equine animals worldwide for centuries. It has been more common in some breeds of horses in the United States, but there is no breed "immunity". In the UK, it is a notifiable disease. There is no known human hazard.
Isoxsuprine is a drug used as a vasodilator in humans and equines. Isoxsuprine is a β2 adrenoreceptor agonist that causes direct relaxation of uterine and vascular smooth muscle via β2 receptors.
Lameness is an abnormal gait or stance of an animal that is the result of dysfunction of the locomotor system. In the horse, it is most commonly caused by pain, but can be due to neurologic or mechanical dysfunction. Lameness is a common veterinary problem in racehorses, sport horses, and pleasure horses. It is one of the most costly health problems for the equine industry, both monetarily for the cost of diagnosis and treatment, and for the cost of time off resulting in loss-of-use.
Primitive markings are a group of hair coat markings and qualities seen in several equine species, including horses, donkeys, and asses. In horses, they are associated with primitive breeds, though not limited to such breeds. The markings are particularly associated with the dun coat color family. All dun horses possess at least the dorsal stripe, but the presence of the other primitive markings varies. Other common markings may include horizontal striping on the legs, transverse striping across the shoulders, and lighter guard hairs along the edges of a dark mane and tail.
Dominant white (W) is a group of genetically related coat color alleles on the KIT gene of the horse, best known for producing an all-white coat, but also able to produce various forms of white spotting, as well as bold white markings. Prior to the discovery of the W allelic series, many of these patterns were described by the term sabino, which is still used by some breed registries.
Roan is a horse coat color pattern characterized by an even mixture of colored and white hairs on the body, while the head and "points"—lower legs, mane, and tail—are mostly solid-colored. Horses with roan coats have white hairs evenly intermingled throughout any other color. The head, legs, mane, and tail have fewer scattered white hairs or none at all. The roan pattern is dominantly inherited, and is found in many horse breeds. While the specific mutation responsible for roan has not been exactly identified, a DNA test can determine zygosity for roan in several breeds. True roan is always present at birth, though it may be hard to see until after the foal coat sheds out. The coat may lighten or darken from winter to summer, but unlike the gray coat color, which also begins with intermixed white and colored hairs, roans do not become progressively lighter in color as they age. The silvering effect of mixed white and colored hairs can create coats that look bluish or pinkish.
Chapman's zebra, named after explorer James Chapman, is a subspecies of the plains zebra from southern Africa.
Ann Trommershausen Bowling was an American scientist who was one of the world's leading geneticists in the study of horses, conducting research in the areas of molecular genetics and cytogenetics. She was a major figure in the development of testing to determine animal parentage, first with blood typing in the 1980s and then DNA testing in the 1990s. She later became known for her studies of hereditary diseases in horses and equine coat color genetics, as well as research on horse evolution and the development of horse breeds. She studied the population genetics of feral horses, did considerable work to help preserve the Przewalski's horse, and was one of the founding members of the international project to map the horse genome. She was an adjunct professor at the University of California, Davis (UCD), and at the time of her death in 2000 was the executive associate director of the Veterinary Genetics Laboratory (VGL) there. Her unexpected death on December 8, 2000, at age 57 was attributed to a massive stroke.
References
- ↑ Bragulla, Hermann (1991). "Die hinfällige Hufkapsel (Capsula ungulae decidua) des Pferdefetus und neugeborenen Fohlens*" [The deciduous hoof capsule (Capsula ungulae decidua) of the equine fetus and newborn foal]. Anatomia, Histologia, Embryologia (in German). 20 (1): 66–74. doi:10.1111/j.1439-0264.1991.tb00293.x. PMID 1877762. S2CID 221396589.
- 1 2 3 Ginther, Oliver J. (2022). "Physical Interplay between Equine Fetus and Uterus from Day 180 to End of Pregnancy". Journal of Equine Veterinary Science. 112: 103918. doi:10.1016/j.jevs.2022.103918. PMID 35257827. S2CID 247266319.
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