Dust exposure and pulmonary inflammation in Standardbred racehorses fed dry hay or haylage: A pilot study.

Respirable dust exposure is linked to airway inflammation in racehorses. Feeding haylage may reduce dust exposure by 60-70%. The objective of this study was to compare dust exposure, airway cytology, and inflammatory cytokine concentrations between horses fed haylage or hay over 6 weeks while in training. Seven healthy Standardbred horses were randomly assigned to be fed alfalfa hay (n = 3) or grass-alfalfa mix haylage (n = 4) for six weeks while training on a treadmill. Dust exposure was measured gravimetrically at the breathing zone. Endotoxin and ß-glucan concentrations in respirable dust were measured. Bronchoalveolar lavage fluid (BALF) cytology was determined at baseline and after 2, 4, and 6 weeks. Cytokine concentrations (interferon-γ, tumor necrosis factor-α, and interleukin-4) were measured in BALF at baseline and week 6. The effect of forage on exposure, airway cytology and cytokines were evaluated using generalized linear mixed models. Respirable dust and ß-glucan exposures were lower in horses fed haylage than hay (0.02 ± 0.001 mg/m3 vs. 0.06 ± 0.01 mg/m3; P = 0.03, and 69 ± 18 pg/m3 vs. 160 ± 21 pg/m3; P = 0.02, respectively). In horses eating haylage, BALF neutrophil proportion decreased between baseline (2.2 ± 0.5%), week 2 (0.8 ± 0.3%; P = 0.01) and week 6 (0.7 ± 0.2%; P = 0.03). By week 6, horses fed haylage had lower BALF neutrophilia than horses fed hay (4.0 ± 0.7 %; P = 0.0004). Interleukin-4 concentration in BALF was higher at week 6 (14.4 ± 4.6 pg/mL) in horses fed hay compared to baseline (2.9 ± 4.6 pg/mL; P = 0.007). In conclusion, feeding haylage instead of hay to horses in training can reduce exposure to respirable irritants and mitigate airway neutrophilia.

The Effect of Fasting Duration on Baseline Blood Glucose Concentration, Blood Insulin Concentration, Glucose/Insulin Ratio, Oral Sugar Test, and Insulin Response Test Results in Horses.

OBJECTIVES: Published descriptions of the oral sugar test (OST) and insulin response test (IRT) have been inconsistent when specifying the protocol for fasting horses before testing. The purpose of our study was to examine the effect of fasting duration on blood glucose concentration, blood insulin concentration, glucose/insulin ratio, OST, and IRT results in horses. ANIMALS: Ten healthy adult horses. PROCEDURES: Both OST and IRT were performed on horses without fasting and after fasting for 3, 6, and 12 hours. Thus, 8 tests were performed per horse in a randomized order. Blood collected at the initial time point of the OST was analysed for both blood glucose and serum insulin concentrations so that baseline concentrations and the glucose/insulin ratio could be determined. Unless fasted, horses had free-choice access to grass hay. RESULTS: There was no effect of fasting and fasting duration on blood glucose concentration, serum insulin concentration, glucose/insulin ratio, or the OST. Response to insulin in the IRT was decreased in fasted horses. The effect increased with fasting duration, with the least response to insulin administration after a 12-hour fast. CONCLUSIONS AND CLINICAL RELEVANCE: These data indicate that insulin sensitivity is not a fixed trait in horses. Fasting a horse is not recommended for a glucose/insulin ratio or IRT, and fasting a horse for 3 hours is recommended for the OST.

What's New in Old Horses? Postmortem Diagnoses in Mature and Aged Equids.

Postmortem findings in 241 equids admitted to a teaching hospital that were at least 15 years old at autopsy were reviewed (1) to determine disease prevalence, (2) to compare the cause of death (or euthanasia) in equids 15 to 19 years of age (n = 116) with that in equids ≥20 years of age (n = 125), and (3) to catalog coexisting lesions in equids with pituitary pars intermedia dysfunction (PPID). Breed and sex were evenly distributed between the age groups. Death or euthanasia was attributed to disease of the digestive system (41.5%), pituitary gland (12.9%), locomotor system (10.0%), nervous system (7.9%), cardiovascular system (4.6%), urinary system (4.6%), reproductive system (4.2%), respiratory system (4.2%), integumentary system (4.2%), lymphoid system (2.5%), liver (2.5%), or systemic neoplasia (1.2%). Nervous system disease was more common in the 15- to 19-year group; urinary tract disease was more common in the ≥20-year group. Neoplastic disease, regardless of systemic location, was the basis for death or euthanasia in 18.7% of all equids. Squamous cell carcinoma, lymphoma, and melanoma were the most common malignant neoplasms. PPID was the most common specific diagnosis, based on the postmortem presence of hyperplasia or adenoma, and was the reason for euthanasia in 47.7% of 65 equids with PPID. The most common nonpituitary causes for death or euthanasia in equids with PPID were colic, lameness, cancer, and spinal cord disease. Coexisting conditions in equids with PPID that were not considered the basis for euthanasia included neoplasms, infections, lameness, and recurrent airway obstruction.

Clinical findings and survival in 56 sick neonatal New World camelids.

BACKGROUND: Information pertaining to clinical presentation and outcome of neonatal New World camelids (NWC) is limited when compared to calves and foals. HYPOTHESIS: Values of variables at admission and subsequent treatment would predict survival in sick neonatal NWC. ANIMALS: Fifty-six client-owned sick neonatal NWC presented over a 10-year period to the Purdue University Veterinary Teaching Hospital. METHODS: A retrospective study was performed. Inclusion criteria were NWC less than 30 days of age with complete medical records that presented between 2000 and 2010. RESULTS: The median age at presentation was 1 day (range 1-20). The most common diagnoses were systemic inflammatory response syndrome (50%), congenital defects (41%), ophthalmic lesions (21%), sepsis (16%), and gastrointestinal diseases (16%). Sixty-six percent of NWC survived to discharge. Clinicopathologic findings on admission were variable and not specific for disorders. Factors associated with survival were absence of choanal atresia (P = .001, OR: 55.9 [2.5-1,232]), administration of llama plasma (P = .013, OR: 4.9 [1.4-17.7]), and antimicrobial treatment with trimethoprim-sulfamethoxazole (TMS) (P = .016, OR: 6.5 [1.3-32.2]). CONCLUSIONS AND CLINICAL IMPORTANCE: The use of antibiotics, particularly TMS, and llama plasma are recommended in sick neonatal NWC. Results from this study could contribute toward defining a NWC-specific sepsis scoring system.

Arsenic toxicosis in cattle: meta-analysis of 156 cases.

BACKGROUND: Arsenic toxicosis is uncommon in cattle and successful treatment is rarely reported. OBJECTIVES: This analysis reviews all cases of acute arsenic toxicosis in cattle reported in the literature and describes cases from Purdue University that had a favorable outcome. Clinical presentation of the disease, treatments, and variables associated with survival are described. ANIMALS: One hundred and fifty-six cattle with arsenic toxicosis from 16 outbreaks. METHODS: Meta-analysis. RESULTS: The most common clinical signs were sudden death (68%), diarrhea (33%), ataxia (29%), dehydration (22%), and respiratory distress (4%). The most common clinicopathologic abnormalities included azotemia (100%), hematuria (100%), increased liver enzyme activity (86%), and increased hematocrit (60%). One percent of cattle survived and the survival time for nonsurvivors ranged from 20 hours to 21 days. None of the clinical signs or clinicopathologic findings was associated with survival. Treatment was attempted in 24% of cases and was not associated with survival (P = .055), but administration of an antidote and administration of fluids were associated with better outcome (P = .036 and P = .009, respectively). In the animals presented to Purdue University, treatment with IV fluids and sodium thiosulfate resulted in decreased blood arsenic concentrations in all animals (P = .009) and a survival rate of 50%. CONCLUSIONS AND CLINICAL IMPORTANCE: Although acute arsenic toxicosis has a poor prognosis, survival is possible if aggressive fluid therapy and antidotes are administered.

Comparison of a 2-step insulin-response test to conventional insulin-sensitivity testing in horses.

Equine insulin resistance is important because of its association with laminitis. The insulin-response test is described to diagnose insulin resistance in clinical settings. Practitioners may be reluctant to perform this test because of the time needed for the test and the fear of inducing hypoglycemia. The objective of the study was to compare a 2-step insulin-response test with a complete insulin-response test. A complete insulin-response test was performed on 6 insulin-resistant horses and 6 controls. A 2-step insulin-response test consisting of an intravenous injection of 0.1 IU/kg human insulin and blood glucose determination at 0 and 30 min after injection was performed on the same horses. Times to reach a 50% reduction of glucose baseline were compared between tests and horses. All the horses tolerated both tests well. No significant difference was observed between baseline glucose concentrations of insulin-resistant horses and controls (P = 0.09). Time to reach 50% reduction of glucose baseline for controls was not significantly different with the use of the complete insulin-response test or the 2-step test (P = 0.98). For insulin-resistant horses, the time to reach 50% reduction of glucose baseline with the use of the 2-step test was significantly longer than for controls (P = 0.004). With a cut-off time of 30 min, the 2-step test had the same characteristics as the complete test. The 2-step test provided a safe, rapid, and low-cost method to diagnose insulin resistance in horses in a clinical setting.