of the more common penile injuries observed in the bull stud is preputial laceration/avulsion at the site of the preputial reflection. This injury occurs as a friction “tear” due to misapplication of the AV as it is placed on the bull to collect the semen sample. Most often, the only evidence of injury initially will be drops of blood in the AV or in the ejaculate, or by blood dripping from the preputial orifice. This is to be considered a medical emergency and should be addressed as soon as possible after injury. After a pudendal nerve block and/or local anesthesia, the wound should be debrided with copious lavage of the site. Debridement should be followed by suturing with simple interrupted sutures or by surgical stapling. Bandaging of the orifice to maintain the penis in the sheath, with antibiotics and anti‐inflammatory drugs, will be required for several days. After recovery, the bull should only be collected with an electroejaculator or rested from sexual activity for about four weeks.
Occasional preputial lacerations from self‐trauma may occur. It is not uncommon to see bulls “catch” the prepuce with a dew claw as they start to rise. These may only require antibiotics and topical medication instead of debridement and surgery. Each case should be independently assessed. Occasionally, the injury may scar sufficiently to reduce the diameter of the prepuce and impede full extension of the penis. If this occurs a penile reefing or circumcision may be required in the future.
Gastrointestinal Tract Problems
AICs will need veterinary services to treat a wide variety of gastrointestinal problems. Most are simple ruminal tympanies or bloat, followed by non‐specific and transient diarrheas. Most are thought to be due to mistakes in feeding protocols but on occasion may be caused by changes in gastrointestinal motility brought on by a host of other primary problems. These incidents will respond to systemic treatment of laxatives, oral fluids, and analgesics if warranted. More serious gastrointestinal problems encountered include hemorrhagic bowel disease, perforating abomasal ulcers, intestinal intussusception, and intestinal volvulus. Once diagnosed, these are best referred to those most experienced in dealing with such problems as these bulls will need surgery and intensive aftercare.
Occasionally, an acute disease due to a foreign body may occur in a bull at an AIC. Of course, the penetrating foreign body could have been present for years; such subtle problems should not be overlooked when making a differential list. Advising a custom stud owner on per‐os administration of rumen magnets should be considered when creating entry requirements.
Urinary Tract Problems
Urinary tract problems are rare at stud but do occasionally occur. Initial presentation of a bull with urinary obstruction is much like any other abdominal problem: colic‐like symptoms, kicking at abdomen, elevated heart rate, increased salivation, straining attempts to defecate and urinate, etc. Most often bulls may respond to analgesic therapy along with smooth muscle relaxants and urinary acidification. It is to be remembered that if the urinary obstruction is relieved, there are probably still many calculi left in the bladder. When urinary calculi are involved it is wise to diagnose the type of calculi present and adjust therapy accordingly, maintaining the bull on acidification until the calculi significantly decrease in a urine sample. In some areas, calculi do not respond to urinary acidification, presenting the clinician with a whole new set of problems. Most bulls that have calculi problems also have an ongoing cystitis requiring bacterial culture and sensitivity testing and prolonged antibiotic therapy.
Summary
Consulting for an AIC can be rewarding both financially and professionally. Many breeders working with an AIC are the elite within their breed and by exposure to the veterinarian through association with the bull stud new client relationships can develop. Consultation services, from disease prevention to improving reproductive efficiency and development, can occur through contacts made with the AIC.
Acknowledgment
The author wishes to acknowledge his mentor Dr. Wallace Cardwell for his countless contributions to the information found in this chapter.
13 Testicular Degeneration
Albert Barth1 and John P. Kastelic2
1 Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
2 Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
Introduction
Testicular degeneration may be temporary or permanent; temporary degeneration is much more common and, with removal of underlying cause, testis structure and function often recover. It may be difficult to distinguish between degeneration and a severe disturbance of spermatogenesis, with a marked decline in semen quality. The term “degeneration” is somewhat arbitrary, but usually implies reduction in scrotal circumference, testes may be soft, and sperm quality is poor (usually <20% morphologically normal). With temporary degeneration, there is loss of germinal cell layers near the lumen in many or all seminiferous tubules. Sertoli cells and spermatogonia, which are more resistant to damage, are likely to be retained and if the cause of degeneration is removed, tubules are repopulated with spermatocytes and spermatids, restoring testis size and semen quality. Advanced degenerative changes causing permanent damage include spermiostasis, tubular mineralization, granuloma formation, thickened basement membranes, and fibrosis in focal or diffuse areas of testicular parenchyma.
Pathogenesis
Factors involved in pathogenesis of testicular degeneration include abnormal testicular thermoregulation, nutritional excess or deficiency, toxicity, inheritance, congenital blockage of sperm outflow from testes, infectious disease, severe trauma, and senile atrophy.
Testes of scrotal mammals function normally when testis temperature is 2–6 °C below body temperature [1]. Scrotal insulation is a classic model to induce temporary testicular degeneration [2, 3]. In one study, the scrotum was insulated for 10 days; there were reductions in semen quality, but no fibrotic lesions within 6 months after insulation [4]. Therefore abnormal testicular thermoregulation that is reversible (e.g. obesity) may not be a common cause of permanent damage. Other less common causes of chronic abnormal thermoregulation that may lead to temporary or permanent testicular degeneration include severe chronic scrotal dermatitis, heat and swelling due to orchitis, trauma, chronic illness with prolonged fever, endotoxins (potent gonadotropin inhibitors), a congenitally short scrotum, severe scrotal frostbite leading to adhesions, and incomplete descent of a testis into the scrotum.
Obesity is a leading cause of testicular degeneration in bulls. It is common to fatten bulls for livestock shows and sales. Many bulls become obese and fat accumulates in the scrotum, chronically increasing testicular temperatures [2]. However, after a reduction in body condition, including loss of fat from the scrotum, regeneration of seminiferous tubules may occur with return to normal sperm production [5].
Nutritional deficiencies seldom cause testicular degeneration in bulls. Naturally occurring deficiencies are usually multiple and deficiency of any single nutrient as a cause of bull infertility is rare. Similarly, vitamin deficiencies are also rare as a cause of infertility in larger male domestic animals if forages are normal in quality and quantity. However, reductions in feed quality and/or quantity causing weight loss may depress spermatogenesis via an endocrine effect on developing germ cells rather than by vitamin or mineral deficiencies. In one study, protein supplementation of bulls on poor‐quality forage significantly increased dry matter intake, enabling maintenance of live weight, whereas in control (unsupplemented) bulls, weight loss was accompanied by a significant decrease in scrotal circumference and daily sperm production per gram of testis. However, histologically, seminiferous tubule activity was apparently not different between bulls with or without protein