Experimental acute yellow-wood (Terminalia oblongata) intoxication in sheep

SUMMARY An aqueous suspension of air-dried, hammer-milled leaf of Terminalla oblongata (yellow-wood) was administered to sheep by gavage, as a single dose of 5 to 20 g (dry weight)/kg body weight. Doses of 15 g/kg, or more, caused depression, Inappetence, abdominal pain and reduced ruminal movements within 24 to 48 h and some sheep also showed dyspnoea, oplsthotonus and champing of the Jaws. Haematology and blood gas and acid-base measurements were unaffected. In sheep given a dose of 12.5 g/kg, or more, plasma osmolality, aspartate aminotransferase activity and potassium and bilirubin concentrations Increased while plasma total protein markedly decreased and plasma sodium concentration and alkaline phosphatase activity remained normal. Most sheep were necropsled 48 h after dosing. The liver showed zonal hepatocellular necrosis, the pattern of which varied with the dose given. No renal lesions were observed, although one sheep given a very high dose became azotaemic and hyperkalaemic. Hydrothorax, hydroperlcardlum and ascltes developed In sheep given doses of 15 or 20 g/kg.     

Ectopic ureter in the horse: Three cases and a review of the literature

Ureterovesicular anastomosis resulted in resolution of the clinical signs of urinary incontinence in three horses with unilateral ectopic ureter. Follow-up of two of the horses ten months and three years later indicated no further urinary tract problems; the third horse died four days after surgery from intestinal infarction.

Diagnosis can be readily confirmed by antegrade or retrograde ureterography, or endoscopic visualization of the ectopic ureteral openings. Nephrectomy appears indicated in cases of unilateral ectopic ureter with associated ipsilateral urinary tract infection or hydronephrosis, providing the contralateral kidney has normal function. Ureterovesicular anastomosis appears to be indicated in the management of unilateral ectopic ureters in the absence of ascending urinary tract infection or hydronephrosis, and in cases of bilateral ectopic ureters.

     

Subchondral cystic lesions of the proximal extremity of the tibia in horses: 12 cases (1983-2000)

OBJECTIVE: To determine clinical and radiographic features of subchondral cystic lesions (SCL) of the proximal extremity of the tibia in horses that could be used to classify these lesions as being related to osteochondrosis or osteoarthritis and to evaluate results of surgical debridement. DESIGN: Retrospective study. ANIMALS: 12 horses with 14 SCL. PROCEDURE: Medical records and radiographs obtained before and after treatment were reviewed. RESULTS: In 6 young horses (8 lesions), SCL were considered to be related to osteochondrosis; all involved the lateral tibial condyle. The remaining 6 horses were mature and had radiographic evidence of osteoarthritis in addition to SCL. Arthroscopic debridement was performed in 4 horses in which lesions were considered to be a result of osteochondrosis and in 3 horses with osteoarthritis. Three horses in which SCL were considered to be a result of osteochondrosis performed athletically after debridement. Two horses with moderate osteoarthritis returned to work after arthroscopic debridement but at a lower level of athletic performance. One horse with SCL related to osteochondrosis responded to medical treatment and went on to race. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that arthroscopic debridement of SCL is feasible in horses in which lesions involve the cranial portion of the lateral or medial tibial condyle, and that treated horses may be able to perform athletically.     

Clinical and pathologic findings in two draft horses with progressive muscle atrophy, neuromuscular weakness, and abnormal gait characteristic of shivers syndrome

Two Belgian geldings, 4 and 14 years old, respectively, with muscle atrophy, weakness, and abnormal gait characteristic of severe advanced shivers were examined clinically and on necropsy. Neurologic examination revealed no evidence of ataxia, and the clinical diagnosis was neuromuscular weakness and shivers. Necropsies of both horses, including examination of pituitary, brain, spinal cord, spinal roots and ganglia, and peripheral nerves, revealed no gross or histologic abnormalities. Examination of multiple skeletal muscle specimens revealed chronic myopathic changes and periodic acid-Schiff positive, amylase-resistant inclusions within muscle fibers, characteristic of equine polysaccharide storage myopathy. It is suggested that underlying metabolic myopathy may be the cause of muscle weakness and cramping in horses with shivers.     

Investigations into the role of the thyrohyoid muscles in the pathogenesis of dorsal displacement of the soft palate in horses

REASONS FOR PERFORMING STUDY: Contributes to the understanding of the pathogenesis of dorsal displacement of the soft palate during exercise so that management of this condition could be enhanced. HYPOTHESIS: That the thyrohyoid muscles play an important role in the stability of the laryngo-palatal relationship and that dysfunction of these muscles leads to dorsal displacement of the soft palate (DDSP) during exercise. METHODS: Ten horses were exercised on a high-speed treadmill under 4 different treatment conditions: control conditions (n = 10), after resection of thyrohyoid muscles (TH, n = 10), after sham-treatment (n = 5), or after restoration of function of the thyrohyoid muscles with surgical sutures (prosthesis-treatment, n = 6). During trials, the following determinations were made: videoendoscopy of the upper airway, gait frequency and pharyngeal and tracheal static pressures. RESULTS: None of the 10 horses developed DDSP during 2 separate treadmill-exercise trials under the control conditions. Seven of the 10 horses developed DDSP after resection of the TH muscles, 4 of 5 of these horses still experienced DDSP after sham-treatment, but 5 of 6 horses no longer experienced DDSP at exercise after the prosthesis-treatment. There were significant anomalies in airway pressures, respiratory frequency, and occurrence of DDSP in both the TH resection and sham-treatment conditions compared to control conditions. In contrast, no statistical differences were noted in any of the parameters measured between the prosthesis-treatment and control conditions. CONCLUSIONS: That the function of the TH muscles is important to the stability of the laryngo-palatal relationship and plays a role in the pathophysiology of exercise-induced DDSP. POTENTIAL RELEVANCE: Management of horses with DDSP could be enhanced by restoring the function of the TH muscles.     

Treatment of right dorsal ulcerative colitis in a horse

Excessive administration of phenylbutazone was associated with development of right dorsal ulcerative colitis. The clinical signs of right dorsal colitis include chronic colic and weight loss. The laboratory abnormalities include panhypoproteinemia and a high WBC count in the abdominal fluid. Medical management of the chronic colic and protein-losing enteropathy associated with the ulcerative lesions in the right dorsal colon and surgical bypass of the right dorsal colon did not result in long-term resolution of clinical signs. Resection of the ulcerated right dorsal colon through a right lateral approach at the 16th rib resulted in resolution of intestinal protein loss and colic. The results of this case suggest that surgical resection of the ulcerated right dorsal colon may be the recommended treatment for right dorsal ulcerative colitis.     

Immunohistochemical Expression of Growth Factors in the Follicular Wall of Normal and Cystic Ovaries of Sows

The expression of growth factors was evaluated immunohistochemically in normal and cystic ovaries of sows. The immunohistochemically stained area (IHCSA) was quantified by image analysis to analyse the expression of these proteins in the follicular wall of secondary, tertiary and cystic follicles. IGF‐I immunoreactivity was strong in the granulosa cell layer (GC), moderate in the theca interna (TI) and mild in the theca externa (TE) of the normal follicles. There was severe reduction of the labelling to IGF‐I in the GC of the follicular and luteinized cysts. In the normal follicles, the reactivity for IGF‐II was very similar to pattern noted in IGF‐I. There was reduction of the IHCSAs in the GC of the follicular and luteinized cysts, but the decrease was not significant. The staining of the IGF‐II in the TI and TE of the cysts was increased, in comparison with normal follicles. The IHCSAs for VEGF were higher in the GC and TE of the normal follicles in contrast to TI, but this difference was noted only in the tertiary follicle. The VEGF reactivity increased in the GC of the cysts, in relation to normal follicles. The results of the current study show that the formation of ovarian cysts in sows is associated with alterations in the immunohistochemical expression of some growth factors.     

Changes in productivity and profitability of wool-growing farms that follow recommendations from agricultural and veterinary studies

Objective To estimate the changes in productivity and profitability in a group of wool-growing farms as they adopted major recommendations from agricultural and veterinary studies.
Farms Four wool-growing farms in south western Victoria were selected from the clients of the Mackinnon Project, a farm consultancy service run from the University of Melbourne. Each farm had closely followed recommended procedures, kept comprehensive financial and physical records and had been clients for at least 5 years. The comparison group was the South Western Victoria Monitor Farm Project (SWVMFP), about 45 farms in the same region as the study farms that were monitored annually by Agriculture Victoria.
Procedure For a 7-year period, the financial and physical performance of both groups of farms was estimated. Stocking rate, wool production, gross farm income, farm operating costs, net farm income and return on assets were compared.
Results Mean gross farm income of the four study farms steadily rose from 86% of the average SWVMFP farm before the adoption of recommendations to an average of 155%. During the same period, net farm income rose from 70% to 207% of the average of the SWVMFP. Return on asset of the four farms rose irregularly from 26% to 145% of the average of the SWVMFP. Farm operating costs on the four farms were higher than for the SWVMFP group, but the ratio of costs remained relatively constant.
Conclusion The adoption of proven research results was associated with large increases in net farm income. An increase in gross income, rather than a reduction in costs was the main reason for this. Research results offer a way to increase the financial viability of wool-growing farmers, many of whom are currently unable to maintain their lifestyle, resources and infrastructure.     

A computer-derived protocol using recursive partitioning to aid in estimating prognosis of horses with abdominal pain in referral hospitals

In order to determine which variables are useful and accurate in estimating prognosis in horses with abdominal pain, data were analyzed from 231 horses presented at a veterinary teaching hospital. Using multiple stepwise discriminant analysis in a recursive partition model, we obtained a decision protocol that identified survivors and nonsurvivors. The prevalence of survivors was 61% in this population. The sensitivity, specificity, and positive and negative predictive values of this model were 71, 83, 87 and 65%, respectively. This decision protocol was validated by Jackknife classification and also by evaluation with a referral population of 100 horses in which the prevalence of survivors was 83%. This led to sensitivity, specificity, and positive and negative predictive values of 83, 78, 94 and 50%, respectively.