The Veterinary clinics of North America. Equine practice.
Publisher:
W.B. Saunders,
Frequency: Three no. a year
Country: United States
Language: English
Start Year:1985 -
ISSN:
0749-0739 (Print)
1558-4224 (Electronic)
0749-0739 (Linking)
1558-4224 (Electronic)
0749-0739 (Linking)
Impact Factor
1.1
2022
| NLM ID: | 8511904 |
| (DNLM): | SR0053812(s) |
| (OCoLC): | 11078671 |
| LCCN: | sn 84006968 |
| Classification: | W1 VE929F |
Medical examination of horses at auction sales. The role of the veterinarian at auction sales begins long before the consignment is assembled. A number of veterinarians are called upon by sales companies to evaluate the candidates before acceptance into the consignment. At sales time, the number of veterinarians involved grows to large numbers as the prospective buyers employ them to evaluate the animals to suit their individual needs. Professional ethics must be considered at all times when evaluating animals before auction. The findings must be kept confidential. The consignor allows veterinarians to examine his or her animals with the un...
The legal aspects of pre-purchase examinations. This article should be of interest to every veterinarian who performs pre-purchase examinations. Important definitions are included that describe the legal relationship between the buyer, seller, and veterinarian. The author recommends that all examination agreements should be made in writing, signed by the buyer and seller, and include factual representations with respect to the animal to be examined. Copies of sample agreements are included in the Appendix.
Examination of the upper and lower respiratory tract relevant to purchase. The intent and extent of the respiratory tract examination relevant to purchase are dictated by numerous factors, including historical information, signs suggestive of respiratory tract abnormalities, intended use of the horse, and economic considerations. Following a thorough and systematic examination of the horse at rest, evaluation during and following exercise may be warranted. The physical examination should include evaluation of regional symmetry of the head, neck, and thorax; evaluation of nasal airflow and patency; palpation of the nasal septum, larynx, and trachea; examination for su...
Recording of the medical evaluation relevant to purchase. In reporting the results of the medical examination for purchase, the veterinarian should not make an evaluation as to the animal's suitability for the purpose intended but should rather reveal all of the abnormal and undesirable findings and give his or her opinion as to the effect these findings will have on the performance of the horse for the purpose intended. A written report should be provided, and any factors that have had an influence on the opinion rendered should be a part of the report. A record of all procedures performed, the results of these procedures, the names and addresses of...
Medical examination of the digestive system relevant to purchase. Routine examination of the digestive system relevant to purchase includes gross examination of the feces, auscultation of the abdomen, and examination of the oral cavity and teeth for verification of age and identification of any gross abnormality. Further examination is indicated only when there is a history of diseases such as colic, especially colic surgery, or esophageal obstruction. Special procedures that might be indicated, depending upon the history and findings on the routine physical examination, include rectal palpation of the abdominal viscera; endoscopic examination of the esophag...
Medical evaluation of the eye relevant to purchase. Performance and pleasure horses depend upon their ability to see and assess the environment. Thus, the veterinarian must be able to examine the eyes and recognize abnormalities so that the owner or purchaser can be informed about the visual status and prognosis for the horse's vision. If the veterinarian encounters suspicious or abnormal findings during the examination, a more detailed examination and/or referral to a veterinary ophthalmologist can be recommended to the owner or purchaser.
Normal and abnormal sexual behavior. This article includes a brief description of the reproductive patterns and specific behaviors comprising courtship and copulation in equids. The author then focuses on breeding behavior of the domestic stallion. Descriptions of normal breeding behavior under a variety of domestic management systems, comments on sexual behavior of donkeys and exotic equids, and the most common types and treatments of sexual behavior dysfunction are included.
Training the novice stallion for natural breeding. There are myriad problems that can arise when training the novice stallion for natural service. Many problems can be avoided by proper early training of the novice stallion. In the final analysis, common sense should prevail. The major ally of common sense is patience. One should keep in mind that the goal is to have a stallion behave in a disciplined manner, allowing for his expression of libido and effective mounting, intromission, and ejaculation. This is accomplished through judicious training and, as with any training process, takes some time and work. Proper training will help circumvent...
Endocrine abnormalities and hormonal therapy. Routine measurement of estrogens, testosterone, T4, insulin, FSH, and LH at least four times per year (e.g., during each of the four seasons) may improve the efficiency of stallion management. Benefits may not be realized in the short term but will provide valuable historical data on individual stallions that, when added to other data, will improve ability of management personnel to initiate early treatment and delay or slow declining fertility. This ability will be greatly improved as more data and products become available. There appears to be a relationship between low total estrogen concen...
Ultrasonographic evaluation of the testis, epididymis, and spermatic cord of the stallion. Ultrasonographic examination of the testis, epididymis, and spermatic cord of the stallion can be used to enhance the routine breeding soundness evaluation of the stallion. Normal ultrasonographic anatomy of the testes and associated structures are presented to aid the clinician in differentiating abnormalities of these structures.
Reproductive anatomy and physiology of the stallion. Examination of the stallion's reproductive tract involves assessments of external and internal anatomy. External examinations are performed by visual inspection, palpation, or ultrasonography and include the scrotum, testes, epididymides, penis, and prepuce. Internal examinations may be performed by rectal palpation, transrectal ultrasonography, or endoscopy and include the accessory sex glands, pelvic urethra, and inguinal rings. A fertile stallion must produce, transport, store, and deliver viable spermatozoa to the mare. The physiologic processes involved include neuroendocrine control, spe...
Transrectal ultrasonography for the evaluation of stallion accessory sex glands. This article reviews the capabilities of transrectal ultrasonography for determining the distribution of fluid and tissue within stallion accessory sex glands. Emphasis is placed on describing the normal ultrasonographic appearance of the accessory sex glands, excurrent ducts, and pelvic urethra of stallions during rest, after teasing, and after ejaculation and using this information to detect glandular abnormalities.
Semen collection techniques. Semen collection techniques in the stallion have evolved considerably over the last 70 to 80 years and are used today primarily for artificial insemination. Semen can be collected from stallions that are otherwise unable to breed, allowing continued use of valuable animals. There are many options for collection of semen from stallions that present with ejaculatory dysfunction (see the article by McDonnell elsewhere in this issue.) Although there are many advantages to the use of artificial breeding, the collector must understand each step of the collection procedure as well as stallion prefere...
Evaluation of stallion semen. This article outlines a basic method for conducting a stallion semen evaluation. After the removal of the gel fraction of the ejaculate, semen gel-free volume is determined, and any abnormality in appearance is noted. Concentration of sperm cells in semen can be determined with the use of either a hemacytometer or spectrophotometer after appropriate dilution of raw semen. The percentage of progressively motile sperm is evaluated promptly after collection of semen with the use of a phase-contrast microscope. The total numbers of sperm and progressively motile sperm in the ejaculate are calculat...
Ejaculation. Physiology and dysfunction. In summary, important events of ejaculation include emission of sperm and the accessory gland fluids into the urethra, simultaneous closure of the bladder neck, and forceful ejaculation of the combined semen through the urethra. Emission and bladder neck closure are primarily alpha-adrenergically mediated thoracolumbar sympathetic reflex events with supraspinal modulation. Ejaculation is a sacralspinal reflex mediated by the pudendal nerve. In stallions, the most common ejaculation disorders are emission and ejaculation failure, and urine contamination of semen. Rare disorders are azoospermia ...
Training the novice stallion for artificial breeding. Although the act of breeding is instinctive to the stallion, the use of a phantom mare and AV represent an unnatural element to this act. The use of these devices, as well as proper breeding manners and etiquette, must be taught to the stallion. The novice stallion usually learns these techniques rapidly and is quite manageable if proper restraint is used during training. Positive reinforcement for good behavior is essential. The ultimate goal in training the novice stallion is to develop an individual that will enter the breeding area with controlled enthusiasm, develop an erection and gracef...
Endocrine and testicular changes associated with season, artificial photoperiod, and the peri-pubertal period in stallions. The seasonal reproductive cycle of stallions is characterized by an annual regression and recrudescence in testicular function and concentrations of LH, FSH, and testosterone in serum. Maximum reproductive capacity occurs during the increasing day lengths of spring and summer. The annual cycle in LH secretion may reflect a seasonally associated and photosensitive reduction and replenishment in pituitary content of LH. Similar to other seasonal breeders, it appears that stallions may possess an endogenous circannual rhythm in reproductive function that is subject to manipulation by altering the...
Management of stallions on large breeding farms. Often, there is an adversarial relationship between senior management and livestock managers. It is important that the veterinarian responsible for breeding management and health care maintain open communications with senior managers. Although the veterinarian may recognize livestock-management deficiencies that need changing, he or she must remain flexible within the constraints provided on the breeding farm. Years may be required to solidify this give-and-take relationship, and opinions on the value of many management procedures will change. The underpinnings of a successful stallion manager...
Evaluation of the stallion for breeding soundness. The breeding soundness evaluation of a stallion is a thorough investigation of a stallion's libido, mating ability, and semen quality. The evaluation should include historical data about the medical aspects of the horse's performance and breeding career, observations and breeding behavior characteristics, collection and evaluation of semen, tests to determine freedom from infectious or contagious disease, and production of foals free of genetic defects. This information should allow the examiner to anticipate the impact of the stallion on the reproductive efficiency of a group of mares. The br...
Artificial insemination and preservation of semen. Artificial insemination is an effective technique for improving utilization of stallions in breeding programs. When proper semen handling and insemination procedures are used, optimal pregnancy rates are attainable. When AI techniques are employed for mares and stallions with marginal fertility, pregnancy rates may be improved in comparison with natural mating. Preservation of stallion semen in the liquid or frozen state reduces the costs and potential health hazards incurred by transporting mares and provides easier access to genetic material that may otherwise be unavailable. Acceptable preg...
Venereal disease. Equine venereal infections of concern in the United States include EHV-3, T. equigenitalis, P. aeruginosa, and K. pneumoniae. Stallions may also harbor EAV in the genital tract and transmit the virus to mares during coitus. With the exception of EHV-3, the stallion generally remains asymptomatic while transmitting infections to mares during breeding. Methods for diagnosis, treatment, and control of these infections are discussed.
Standing laparoscopic surgery. Laparoscopic procedures can replace many more invasive procedures. Guided visceral biopsy, cryptorchid castration, ovariectomy, and limited abdominal exploration may be done laparoscopically in the standing horse.
Standing surgical procedures of the foot. Several surgical conditions affecting the foot can be successfully managed with the horse standing. Many factors affect the clinician's choice of whether to perform surgery with the horse standing or anesthetized. Temperament or pregnancy of the horse and economics may influence the decision to perform surgery with the horse standing. This article discusses several foot conditions that can be treated successfully in the ambulatory horse.
The pharmacology of local anesthetics. Understanding of the pharmacology of local anesthesia is important for selection of a local anesthetic for use in equine standing surgery. In general, the action potential is inhibited by local anesthetics by preventing the influx of sodium ions across the axonal membrane. The physicochemical properties of each local anesthetic determine the onset of action, potency, and duration of action. Procaine, chlorprocaine, lidocaine, and mepivacaine are the local anesthetics still used clinically in horses; lidocaine is the most widely used. The future of equine local anesthesia may see the introducti...
Standing rectal and tail surgery. A variety of rectal, perirectal, and coccygeal surgeries can be performed in the standing equine patient if appropriate chemical and physical restraints are available and adequate regional anesthesia can be achieved. Some rectal tears and most rectal prolapses, mass lesions, perirectal abscesses, rectal biopsies, and selected injuries of the tail can be managed without prohibitive difficulty. Severe injuries that compromise the small colon cranial to the peritoneal reflection may require flank laparotomy, midline celiotomy, or humane euthanasia to manage the disease process effectively and app...
Standing endoscopic electrosurgery. Common equine upper respiratory conditions are diagnosed via endoscopy. Endoscopic surgery facilitates correction of many conditions without general anesthesia or laryngotomy, reducing the morbidity and cost of the procedures. Modalities of endoscopic surgery include the Nd-YAG laser or electrosurgery, which may be complementary. The least expensive method is electrosurgery, and instruments are available that can be passed through the biopsy channel of the endoscope. Conditions amenable to such procedures include entrapped epiglottis, rostral displacement of the palatopharyngeal arch, pharynge...
Chemical restraint for surgery in the standing horse. Chemical restraint can be a useful pharmacologic tool to assist the veterinarian performing surgery in the standing horse. The agents discussed impose minimal adverse side effects and are considered relatively safe when administered in the doses described. Acetylpromazine, the most widely used tranquilizer, produces mild sedation but no analgesia. The use of tranquilizers for surgical procedures requires the combined use of either a local anesthetic technique or a sedative-hypnotic or opiate to provide analgesia. Sedative-hypnotics such as xylazine and detomidine or opiates such as morphine an...
Standing musculoskeletal surgery. Indications for performing orthopedic surgery on the standing horse include inability to tolerate general anesthesia, risk of worsening an injury during recovery from anesthesia, and cost. The surgeon should be aware that performing surgery in the standing horse can be more demanding and require more experience than the same procedures when the time and convenience of general anesthesia are available. Improved sedatives and analgesics have allowed more latitude because the horses now are more tolerant than when older agents were used. Common sense should be applied to each situation before the...