Corneal Ulcers in Critically Ill Foals in Intensive Care: Case Series of Standard Treatment and Corneal Cross-Linking.

Riboflavin/UV-A corneal cross-linking (CXL) has been applied to treat corneal ulcers in adult horses, but its use in critically ill neonatal foals has not been described. Five cases of hospitalized, critically ill neonatal foals that were in intensive care with corneal ulcers, the ophthalmic treatment, and their outcome up to 1 year are described. A single treatment of CXL phototherapy was performed in three of five foals (five eyes). The application of a riboflavin ophthalmic solution for 20 minutes was followed by the UV-A light irradiation at 30 mW/cm2 for 3 minutes. Topical antibiotic administration was withdrawn after CXL. Two other foals received standard treatment. Descriptions of ocular lesions, fluorescein staining, and photographic documentation were recorded. The visual outcome, corneal transparency, and aesthetics, as well as healing time were evaluated in the follow-up. The frequency of topical medication considerably decreased in cases treated with CXL. Corneal opacity and pain decreased within 3 days following CXL. In the foals treated with CXL, the ulcers healed (fluorescein stain negative) in 24, 28, and 35 days after the onset of clinical signs and 10, 15, and 21, after CXL. No fibrosis or corneal scars were found in the cases treated with CXL. The two standard treatment cases healed after 26 and 36 days respectively. Corneal cross-linking may be an additional or alternative treatment of corneal ulcers in critically ill neonatal foals and may reduce the use of antibiotics.

Susceptibility pattern of bacterial isolates in equine ulcerative keratitis: Implications for empirical treatment at a university teaching hospital in Sydney.

Corneal ulceration is a common ophthalmic condition in horses. It is frequently caused by trauma to the corneal surface, followed by secondary infection by commensal or pathogenic organisms including Streptococcus equi subspecies zooepidemicus, Pseudomonas aeruginosa and Staphylococcus spp. Emerging antimicrobial resistance amongst these organisms has raised the need for appropriate antimicrobial therapy selection, to optimise treatment efficacy while minimising further antimicrobial resistance. Medical records of 38 horses presented at the University Veterinary Teaching Hospital Camden for ulcerative keratitis between 2010 and 2020 were reviewed to identify those with positive bacterial cultures and antimicrobial susceptibility profiles (13/38). Common susceptibility patterns were identified and used to guide the empirical treatment of equine bacterial corneal ulcers. Pseudomonas spp. (64.3%), Streptococcus equi subspecies zooepidemicus (14.3%) and Actinobacillus spp. (14.3%) were most commonly identified. Susceptibility to amikacin, gentamicin and ciprofloxacin was observed in 100%, 66.7% and 85.7% Pseudomonas spp. isolates respectively. Resistance to polymyxin B and neomycin occurred in 85.7% and 71.4% of Pseudomonas spp., respectively. All Streptococcus equi subspecies zooepidemicus organisms in this study were susceptible to ceftiofur, cephalexin, penicillin and ampicillin, while they were all resistant to gentamicin, neomycin, enrofloxacin and marbofloxacin. Predominating in this study, Pseudomonas spp. maintained overall aminoglycoside susceptibility despite some emerging resistance, and good fluoroquinolone susceptibility. High resistance to Polymyxin B could have arisen from its common use as first-line therapy for bacterial corneal ulcers. Although further research is required, these new findings about predominant bacteria in equine corneal ulceration in the Camden region and their antimicrobial susceptibility patterns can be used to guide the empirical treatment of bacterial corneal ulcers in horses.

Long-chain polyunsaturated fatty acid supplementation increases levels in red blood cells and reduces the prevalence and severity of squamous gastric ulcers in exercised Thoroughbreds.

OBJECTIVE: To assess the relationship between plasma and RBC fatty acid composition and incidence and severity of squamous gastric ulcers when altered by short-chain (SC) or long-chain (LC) polyunsaturated fatty acid (PUFA) supplementation. ANIMALS: 13 fit Thoroughbred horses in training. PROCEDURES: Horses were evaluated by gastroscopy for squamous ulcer score, gastric pH, and blood fatty acid composition prior to supplementation (UNSUPP) and after 3 months of supplementation with a corn-flax oil blend of alpha-linolenic acid and linoleic acid (SC-PUFA) or a gamma-linolenic acid (GLA)-fish oil blend of GLA, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA; LC-PUFA) in a crossover design. Prior to gastroscopy and blood collection, horses performed a 4,600-m standardized exercise test on the racetrack as a stressor. RESULTS: Three months of supplementation with LC-PUFAs increased RBC levels of GLA, dihomo-gamma-linolenic acid (DGLA), arachidonic acid (AA), EPA, and DHA, and reduced severe ulcer prevalence (38% UNSUPP vs 8% LC-PUFA with a severe ulcer score of grade 3 to 4). Short-chain PUFA supplementation did not effectively elevate RBC GLA, DGLA, AA, EPA, or DHA and severe ulcer incidence was not different (38% UNSUPP vs 23% SC-PUFA with a severe ulcer score of grade 3 to 4). Lower levels of RBC GLA, DGLA, AA, and EPA correlated with severe squamous gastric ulceration (grade 3 to 4). CLINICAL RELEVANCE: Equine gastric ulcer syndrome is prevalent in high-performance horses and is a concern to owners and trainers. Long-chain PUFA supplementation increased levels of GLA, DGLA, AA, EPA, and DHA, unlike SC-PUFA supplementation, and was associated positively with prevention or resolution of severe squamous gastric ulceration. Further studies are needed to evaluate different management styles and exercise intensities.

Isolation, identification, and pathogenic characteristics of Nocardia seriolae in largemouth bass Micropterus salmoides.

The largemouth bass Micropterus salmoides is an important freshwater aquaculture fish in China. Recently, largemouth bass at a fish farm in Guangdong province experienced an outbreak of a serious ulcer disease. As part of the investigations conducted to identify the aetiology and identify potentially effective control measures, we isolated a pathogenic bacterium (NK-1 strain) from the diseased fish. It was identified as Nocardia seriolae through morphological observation, physiological and biochemical analysis, and molecular identification, and its pathogenicity was verified by experimental infection. Pathological changes in the diseased fish included granulomatous lesions in the liver and spleen, destruction of renal tubules, necrosis of intestinal epithelial cells, infiltration of inflammatory cells in the brain, vacuolation of cells, and swelling and cracking of the mitochondria and endoplasmic reticulum. Bacterial detection using qPCR showed that the spleen and intestine were the main organs targeted by N. seriolae. The mortality of largemouth bass experimentally infected with N. seriolae at 21°C was significantly lower than that in fish infected at higher temperatures between 24 and 33°C; there were no significant differences in the levels of mortality at these higher temperatures. The level of mortality of largemouth bass infected with N. seriolae was lowest at a neutral water pH of 7 but increased significantly at higher and lower pH. Of the tested Chinese herbal medicines, Chinese sumac Galla chinensis and Chinese skullcap Scutellaria baicalensis exhibited the best antibacterial effects. This study lays a foundation for the clinical diagnosis and scientific control of ulcer disease in largemouth bass.

Effect of an orally administered antacid agent containing aluminum hydroxide and magnesium hydroxide on abomasal luminal pH in clinically normal milk-fed calves.

OBJECTIVE: To determine the effects of a commercially available orally administered antacid agent containing aluminum hydroxide and magnesium hydroxide on abomasal luminal pH in clinically normal milk-fed calves. DESIGN: Randomized trial. ANIMALS: 5 male dairy calves. PROCEDURE: Throughout the study, calves were fed milk replacer at 7:30 AM and 7:30 PM. Cannulae for pH electrodes were placed in the abomasal body and pyloric antrum. Treatments consisted of oral administration of a high (50 ml) or low (25 ml) dose of the antacid agent and oral administration of milk replacer alone (control). Antacid was given at 7:30 AM, 3:30 PM, and 11:30 PM, and luminal pH was monitored continuously for 24 hours, beginning 15 minutes before administration of the first dose of antacid. RESULTS: Administration of the first dose of antacid at the time of the morning feeding resulted in an increase in mean abomasal body luminal pH of < 1 pH unit, whereas administration of the second and third doses of the antacid caused transient (< 3 hours) increases in mean luminal pH of approximately 1.5 (low dose) and 2.5 (high dose) pH units. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that clinically normal milk-fed calves given a commercially available antacid agent, PO, will have a transient increase in abomasal luminal pH. Such agents may, therefore, have a role in the treatment of abomasal ulceration in calves; however, the long-term effects of orally administered antacid agents in milk-fed calves and the clinical efficacy of such agents in treating abomasal ulceration remain to be determined.

Probable toxicosis in cattle in Israel caused by the oak Quercus calliprinos.

A probable outbreak of oak (Quercus calliprinos) toxicosis in a herd of beef cattle--heifers and first-calving cows--grazing in the Judean foothills of Israel is described. Toxicosis probably occurred because of the consumption of oak leaves and buds during a period of pasture scarcity without any feed supplementation. A progressive syndrome of wasting, dullness, anorexia, polyuria, nephrosis, constipation and recumbency, culminating in death, was seen. A high mortality rate of 83% (38/46 animals) was noted. The clinical-pathological findings revealed increases in blood urea, creatinine, aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT), creatine kinase (CK), lactate dehydrogenase (LDH) and inorganic phosphorus. Decreases were found in alkaline phosphatase (ALP), total serum protein, albumin (ALB), triglyceride (TG), calcium (Ca), magnesium (Mg), sodium (Na) and chloride (CI). The main pathological findings were severe nephrosis, chronic interstitial nephritis, and occasional intestinal ulceration. On the basis of epidemiology, clinical signs, clinical-pathological and pathological findings and renal histology, a tentative diagnosis of oak toxicosis was made.

Effects of large doses of phenylbutazone administration to horses.

The effects of large doses of phenylbutazone were evaluated in clinically normal horses. The drug was given to 4 groups of 2 horses each at the rate of 30 mg/kg of body weight, orally, or 30, 15, or 8 mg/kg IV daily for up to 2 weeks. All horses became anorectic and depressed after 2 to 4 phenylbutazone treatments, and the horses given 15 or 30 mg/kg died on or between days 4 and 7 of treatment. A decrease in total blood neutrophil count occurred in all horses, and was associated with toxic left shift in horses given the 2 larger dosage schedules. The horses also had progressive increases in serum urea nitrogen, creatinine, and phosphorus concentrations, accompanied by decreasing serum calcium concentrations. There was a progressive decrease in total serum protein in all 8 horses. Gastrointestinal ulcerations, renal papillary necrosis, and vascular thromboses were the predominant postmortem findings.