The influence of rapid growth on sodium salicylate pharmacokinetics in male turkeys

The aim of this study was to assess the influence of growth on the pharmacokinetics of sodium salicylate (SS) in male turkeys. SS was administered intravenously at a dose of 50 mg/kg. Plasma drug concentrations were assessed by high‐performance liquid chromatography, and pharmacokinetic parameters were calculated by noncompartmental analysis. As the age increased from 6 to 13 weeks (body weight increase from 2.35 to 9.43 kg), median body clearance decreased from 1.34 to 0.87 ml/min/kg. This caused a significant increase in the median mean residence time from 3.42 to 4.44 hr. Elimination phase proved to be biphasic and two elimination half‐lives (T_1/2el) were distinguished. Whereas T_1/2el1 was found to increase with age by 128%, T_1/2el2 represented a later but faster and less age‐dependent phase of elimination (increase by 56% in the respective groups). Volume of distribution decreased with age. These effects may lead to different therapeutic response to SS in turkeys of different age and body weights.     

<Emphasis Type="SmallCaps">d</Emphasis>-Cloprostenol enhances estrus synchronization in tropical hair sheep

To compare the effects of PGF2α (dinoprost tromethamine) and d-cloprostenol in a two-dose protocol for estrus synchronization in hair sheep during breeding season in Yucatán, México, two experiments were conducted. In experiment 1, 61 cyclic hair sheep were divided into two groups: G1 (control n?=?30), two doses of 50 μg of dinoprost tromethamine IM with 12 days between applications, and G2 (n?=?31), two doses of 50 μg of d-cloprostenol IM at the same time interval. For determination of progesterone levels, 16 ewes from each group were randomly selected. In experiment 2, 70 cyclic hair sheep were assigned at the same treatments (G1 and G2, n?=?35) and 48 h after the second application, the ewes in estrus were detected by two vasectomized rams. Sheep with detected estrus were inseminated, and 45 days after, pregnant animals were identified by ultrasonography. An exact Fisher’s test was performed for the analysis of ewes in estrus (experiments 1 and 2) and number of pregnant ewes (experiment 2); for the comparison of time between end of treatment-estrus presentation, a survival analysis was used. Duration of estrus in hours was analyzed using a generalized mixed model (GLM) ANOVA whereas plasma progesterone concentrations were analyzed by non-linear regression. There were significant differences (P?<?0.05) in the proportion of ewes in estrus upon treatments (G1, 57% vs G2, 87% and G1, 37.1% vs G2, 65.7% in experiments 1 and 2, respectively), and between the end of treatment-onset estrus interval (P?<?0.01), survival curves showed the highest number of sheep in estrus between 40 and 48 h (G1, 43.7?+?8.05 h vs G2, 42.9?+?6.7 h, experiment 1). There were no significant differences (P?>?0.05) in duration of estrus (G1, 42?+?6.1 h, vs G2, 41.1?+?11.2 h, experiment 1) and pregnancy in the ewes that presented estrus, and were inseminated (G1, 38.4% vs 52.1%, experiment 2). With regard to concentrations of progesterone, significant differences (P?<?0.01) were found between treatments, and progesterone levels before the second application of d-cloprostenol were higher. In consideration of the results, it can be concluded that in a two-dose protocol of a luteolytic agent, more ewes presented estrus in response to d-cloprostenol compared to dinoprost tromethamine with similar pregnancy rates.     

A surgical approach to the lateral compartment of the equine guttural pouch in the standing horse: modification of the forgotten "Garm technique"

The objective of this study was to evaluate the feasibility, efficacy and complications following lavage and drainage of the lateral compartment (LC) of the equine guttural pouch (GP) using a modified Garm's technique (MGT). In an ex vivo study (study 1), six cadaver heads were examined to assess the anatomical limits of the surgical approach and whether vital structures might be damaged. This was followed by an in vivo study (study 2) in which a lavage/drainage tube was placed for 3 days into each LC of four standing horses using the MGT. In both studies, the procedure offered direct access into the LC and indirect access into the medial compartments of the GP. In study 1, the MGT provided a rostroventral point of access allowing drainage of the LC, with no obvious iatrogenic damage. In study 2, the MGT permitted lavage of the entire GP in three healthy horses and one horse with mild GP empyema. The only major complication was development of emphysema of the lateral wall of one LC, with secondary collapse of the mucous membrane. The time for secondary wound healing was 12-14 days. The MGT can be performed safely in standing horses and may be of value in providing access for lavage and drainage in horses with mild GP empyema.     

Characterization of Mycobacterium avium subspecies paratuberculosis disseminated infection in dairy cattle and its association with antemortem test results

Mycobacterium avium subspecies paratuberculosis (MAP) disseminated infection in dairy cattle affects animal health and productivity and is also a potential public health concern. The study objectives were to characterize MAP disseminated infection in dairy cattle and to determine the role of antemortem tests in detecting cattle with disseminated infection. Forty culled dairy cows representing a variety of serum enzyme-linked immunosorbent assay (ELISA) results and body conditions were selected for the study. The physical condition of the cows was assessed via clinical examination prior to euthanasia and blood and feces were collected and tested by serum ELISA and fecal culture, respectively. Fifteen tissues were aseptically collected from each cow during necropsy and cultured for isolation of MAP. Disseminated infection was diagnosed when MAP was isolated in tissues other than the intestines or their associated lymph nodes (LNs) and was distinguished from infection found only in the gastrointestinal tissues and from absence of infection. Of the 40 cows in the study, 21 had MAP disseminated infection. Results showed that 57% (12/21) of cows with disseminated infection had average to heavy body condition and no diarrhea. Cows with disseminated infection had no to minimal gross pathologic evidence of infection in 37% (8/21) of cases. Only 76% (16/21) of cows with disseminated infection had positive historical ELISA results and only 62% (13/21) had a positive ELISA at slaughter. Thus, antemortem evidence of MAP infection was lacking in a high proportion of cows where MAP disseminated infection was confirmed.     

Cushing's disease in dogs: cabergoline treatment

The treatment of pituitary-dependent hyperadrenocorticism (PDH) in dogs has for a long time been focused on inhibiting the adrenal gland using drugs such as o-p'-DDD, Ketoconazole and Trilostane, without attacking the primary cause: the corticotrophinoma. Corticotroph cells can express the D2 dopaminergic receptor; therefore cabergoline (Cbg) could be effective as a treatment. Follow-up over 4 years was carried out in 40 dogs with PDH that were treated with Cbg (0.07 mg/kg/week. Out of the 40 dogs, 17 responded to Cbg (42.5%). A year after the treatment, there was a significant decrease in ACTH (p<0.0001), alpha-MSH (p<0.01), urinary cortisol/creatinine ratio (p<0.001), and of the tumor size (p<0.0001) evaluated by nuclear magnetic resonance. Dogs responding to Cbg lived significantly longer (p<0.001) than those in the control group. To conclude, Cbg is useful in 42.5% of dogs with PDH, justifying its use as a treatment.     

Response of Thawed Epidi dymal Red Deer Spermatozoa to Increasing Concentrations of Hydrogen Peroxide,and Importance of Individual Male Variability

Oxidative stress represents a challenge during sperm manipulation. We have tested the effect of increasing hydrogen peroxide (H₂O₂) levels on red deer spermatozoa after cryopreservation, and the role of male‐to‐male variation in that response. In a first experiment, eight thawed samples were submitted to 0, 25, 50, 100 and 200 μm H₂O₂ for 2 h at 37°C. Intracellular reactive oxygen species (H₂DCFDA‐CM) increased with H₂O₂ concentration, but we only detected a decrease in sperm function (motility by CASA and chromatin damage by sperm chromatin structure assay) with 200 μm . Lipoperoxidation assessed by the thiobarbituric acid reactive substance (TBARS) method increased slightly with 50 μm H₂O₂ and above. In a second experiment, samples from seven males were submitted to 0 and 200 μm H₂O₂ for 2 h, triplicating the experiment within each male. Males differed at thawing and regarding their response to incubation and H₂O₂ presence. We found that the kinematic parameters reflected male‐to‐male variability, whereas the response of the different males was similar for lipid peroxidation and viability. A multiparametric analysis showed that males grouped differently if samples were assessed after thawing, after incubation without H₂O₂ or after incubation with H₂O₂. Red deer spermatozoa are relatively resilient to H₂O₂ after thawing, but it seems to be a great male‐to‐male variability regarding the response to oxidative stress. The acknowledgement of this individual variability might improve the development of optimized sperm work protocols.     

Outbreak of acute bovine viral diarrhea in Brazilian beef cattle: clinicopathological findings and molecular characterization of a wild-type BVDV strain subtype 1b

When first described in 1946, bovine viral diarrhea (BVD) was characterized as an acute transmissible disease associated with severe leucopenia, high fever, depression, diarrhea, gastrointestinal erosions, and hemorrhages. Recently the severe acute form has been related only to some hypervirulent BVDV-2 strains. This article reports the detection of BVDV-1b associated with an acute and fatal outbreak of BVD in a Brazilian beef cattle herd. Depression, anorexia, watery diarrhea, sialorrhea, and weakness were observed in six steers. One of these animals was evaluated for laboratorial, clinical, and pathological alterations. Laboratory findings were non-specific; clinically, the animal was weak, with dehydration and erosive oral lesions. Pathological alterations were predominant at the tongue, esophagus, and rumen. A RT-PCR assay using primers to partially amplify the 5′ untranslated region (5′UTR) of the BVDV genome was performed and identified BVDV in all clinical samples analyzed. Phylogenetic analysis of BVDV derived from lymph node revealed that this strain was clustered within the BVDV subtype 1b. This differentiating was only possible to be performed by molecular characterization since both clinical presentation and pathologic findings were similar to BVDV-2 infection.     

Renal handling of calcium and phosphorus in experimental renal hyperparathyroidism in dogs

Twenty-four hour urinary excretion, fractional excretion and the filtered load of calcium and phosphorus were monitored as hyperparathyroidism evolved in a model of progressive canine renal failure. Thirteen beagles of both sexes aged four and a half months were used. Nine of them were subjected to a renal damaging schedule (neomycine, 60 mg/kg/48 h, IM, 32 weeks) in order to induce chronic renal failure leading to secondary hyperparathyroidism (2HPT group). The remaining four were kept as the control group. The experiment was conducted over 32 weeks. Blood and 24 h urine were collected every four weeks. Calcium, phosphorus and creatinine were analyzed. Plasma parathormone and calcitonin were determined at weeks 0, 12, 24 and 32. The level of renal function in the 2HPT animals was reduced to 25% of that of the controls (endogenous creatinine clearance was 0.45 +/- 0.22 mL/min/kg as opposed to 1.81 +/- 0.54 mL/min/kg). Hyperparathyroidism was confirmed by a progressive increase in the levels of the parathyroid hormone. Calcitonin levels were not modified. A tendency to hypocalcaemia was observed, reaching statistically significant levels from the twenty-eighth week of the study, when hyperphosphataemia also became significant. Daily urinary excretion of calcium and phosphorus remained at values considered normal throughout the experiment with no alteration imputable to the impaired renal function. This is explained by the decrease in the filtered load of these elements (in both cases statistically significant from the 24th week on) being associated with an increase in their fractional excretion. Thus, calcium and phosphorus urinary excretion values could be maintained in a normal range up to the end of the experiment, showing that renal calcium handling in dogs with experimentally induced renal failure seems to differ from that observed in human patients.