|
||||
|
Musculoskeletal
and Neurologic Disease Introduction Libido, mounting, thrusting, and ejaculatory dysfunction represent a major cause of poor breeding performance in stallions.1,2 Musculoskeletal and neurologic disease contribute to a considerable portion (as high as half) of these problems.2-4 Poor breeding performance due to musculoskeletal disease has been reported in dairy bulls.5 Stallion breeding soundness examination does not routinely include a complete musculoskeletal and neurologic examination. This paper reviews a series of twenty-three cases of stallions presented to the George D. Widener Hospital or Hofmann Center, University of Pennsylvania, School of Veterinary Medicine, New Bolton Center between 1987 and 1996 either for routine breeding soundness examination, or for evaluation of specific libido or ejaculatory dysfunction, for which the primary cause was determined to be musculoskeletal or neurologic disease. Materials and Methods The case records of stallions presented to our veterinary teaching hospital between 1987 and 1996 for routine breeding soundness examination, or for evaluation of specific libido or ejaculatory dysfunction, for which the primary cause was determined to be musculoskeletal or neurologic disease were examined in this retrospective study. The breeding experience, presenting problem, duration, result of musculoskeletal and neurologic examination, treatment, management, and outcome were determined for each of twenty-three stallions fitting the criteria. Summary statistics were performed. Results The clinical population included stallions representing 5 breeds, 5 performance types, ranging in age from 3 to 19 years. Only one of these was a novice breeder. The duration of poor breeding performance ranged from less than one year to greater than 10 years. Twenty-two of 23 stallions presented with the primary problem of retarded ejaculation. One of twenty-three presented with the primary problem of intermittent falling during breeding. Nine of 23 stallions presented with reduced libido as an additional problem. Two stallions had a secondary problem of falling from the dummy during dismount. Two stallions also had recurrent urospermia as an additional problem. The most common musculoskeletal disease was a sore back, detected in 83% of these stallion cases. Lameness was detected in 70%; degenerative joint disease was detected in 43%; lameness after breeding was detected in 25%; myositis was detected in 17% (Creatine phosphokinase [CK] range 1000-44,000 IU/L =/- 17,000) and laminitis in 13 %. Congenital vertebral malformation was diagnosed in 26% and Equine protozoal myeloencephalitis in 4%. Nonsteroidal anti-inflammatory drugs (NSAID) were the most common medical treatment (78%) followed by acupuncture (22%) and corrective shoeing (13%). Special breeding management techniques (78%) and medication to enhance ejaculation in copula or ex copula (26%) were the most common management techniques. Special long-term management and assisted breeding techniques were found useful for prolonging the breeding life in six horses (26%). Discussion Poor breeding performance can be attributed to musculosketal and/or neurologic disease in many cases. Such cases often present for or with the additional signs of psychological sexual behavior dysfunction. These signs often confound the evaluation and diagnosis of primary factors. It may be difficult to sort out other factors such as novice breeder, footing, artificial vagina conditions, dummy mount or mare factors. Most of the stallions with diagnosis and treatment of musculoskeletal problems typically maintain adequate performance for many years with well-designed management plans and minimal medication 1-4,6. The musculoskeletal and neurologic problems represented in this clinical population were not always evident on traditional lameness exam alone. Examination during breeding is an important component of evaluation of poor breeding performance in stallions. Repeated examinations, before and after breeding and before and after a course of analgesic treatment are often useful. Once a treatment is determined to be effective it is advisable to titrate the medication to the minimum effective dose in order to minimize the risk of side effects with long-term use. It is important to recognize that even though a primary physical cause of poor breeding performance may be identified, successful therapy for such stallions usually requires treatment of the secondary psychological component of the problem. In summary, poor breeding performance in stallions can be a combination of musculoskeletal, neurologic, behavioral, and management factors. Successful evaluation and treatment includes simultaneously recognizing and addressing all of these components. References 1. Martin BB, McDonnell SM, Love CL 1998. Effects of Musculoskeletal and Neurologic disease on Breeding Performance in Stallions. Compendium on Continuing Education 20 (10): 1159-1168. 2. McDonnell SM 1982. Normal and abnormal sexual behavior. Veterinary Clinics of North America Equine Practice 8 (1): 71-89. 3. McDonnell SM 1992. Ejaculation physiology and dysfunction. Veterinary Clinics of North America Equine Practice 8 (1): 57-70. 4. McDonnell SM, Garcia MC, Kenney RM 1987. Imipramine-induced erection, masturbation, and ejaculation in male horses. Pharmacology, Biochemistry and Behavior 27: 187-191. 5. Gelhoedg W 1996. Aging bull. Medical Hypotheses 47(6): 471-479. 6. McDonnell SM, Love CC, Martin BB, Reef VB 1993. Ejaculatory failure associated with aortic-iliac thrombosis in 2 stallions. Journal of the American Veterinary Medical Association 200 (7): 954-957. |
||||
