Sample handling substantially affects Johne's ELISA

Detection methods for Mycobacterium avium subsp. paratuberculosis (MAP) are imperfect, yet crucial for diagnosis of Johne's disease. Our purpose was to test for significant and biologically relevant changes in Johne's ELISA results associated with how field-collected blood samples were transported to the laboratory, prepared and stored prior to testing, while removing potential confounding by test kit and laboratory variables. Blood samples were collected from 21 cows that previously had MAP ELISA scores ranging from negative to highly positive. Samples for immediate laboratory processing were subjected to different transportation temperatures (on ice, 26 °C) and preparation methods (serum separated, hemolyzed and serum separated, clotted whole blood), but were tested using the same ELISA kit in the same laboratory. Samples for laboratory processing after one week of storage were subjected to different storage temperatures (4 °C, −20 °C) and preparation methods (serum separated, hemolyzed and serum separated, clotted whole blood), and again were tested using the same ELISA kit in the same laboratory. Finally, samples were evaluated by time to processing (one day, one week) and storage temperature (4 °C, −20 °C). Data were checked for normality and analyzed with repeated measures ANOVAs. Significantly (P = 0.027) higher MAP ELISA scores were recorded for whole blood and hemolyzed samples transported at 26 °C than serum separated samples. Sample storage for one week at −20 °C resulted in significantly (P < 0.001) lower MAP ELISA scores, regardless of handling method, compared to samples stored at 4 °C for one week. Method of sample preparation, as well as transportation temperature and medium-term storage temperature, affects MAP ELISA results. Such discrepancies will inevitably result in improper classification of MAP-infected cattle, impeding both biosecurity measures on uninfected farms and MAP control programs.     

Effects of blood sample mishandling on ELISA results for infectious bronchitis virus, avian encephalomyelitis virus and chicken anaemia virus

This study determined the effect of sample mishandling on the performance of ELISAs for detection of antibodies against infectious bronchitis virus (IBV), avian encephalomyelitis virus (AEV) and chicken anaemia virus (CAV) in the serum of chickens. The effects of five different sample mishandling treatments were assessed: heat treatment, repetitive freezing and thawing and three levels of severity of haemolysis. These mishandling treatments simulated different conditions that might occur during routine blood collection, transport or storage in a clinical practice setting. Each mishandling treatment was experimentally applied under laboratory conditions and then samples were assayed for antibodies against IBV, AEV and CAV using commercial ELISA kits. Severe haemolysis had the most consistent detrimental effect on ELISA performance, producing results that were significantly different from the reference standard in all three ELISAs, although the direction of the effect varied (less positive for the IBV and CAV assays; more positive for the AEV assay). Moderate levels of haemolysis had a similar, but less consistent, effect to that of severe haemolysis, producing results that were significantly different from the reference standard only for the IBV (less positive) and AEV (more positive) ELISAs. Repetitive freeze-thawing also produced a significant effect on ELISA results for IBV (less positive) and AEV (more positive). The IBV ELISA appeared to be most susceptible to the effects of serum maltreatment. The findings from this study suggest that unpredictable variation in the results of ELISAs can occur due to different sample mishandling treatments.     

Effects of intermittent suckling on the performance and digestive efficiency of Iberian piglets weaned at 35 days of age

During two consecutive replicates Iberian sows (n = 20) were subjected either to a conventional lactation (C) or intermittent suckling (IS). Piglets in the C treatment had free access to the dam. Piglets on IS treatment were separated from the sow during 6 h on days 29 and 30, 8 h on days 31 and 32, and 10 h on days 33 and 34. Litters on both treatments were weaned at 35 days of age and offered a starter diet until day 60 of age. The apparent digestibility (ApD) of nutrients and gross energy (GE) of the post-weaning diet was measured using Cr₂O₃ as external indigestible marker. Litters on IS tended to increase solid feed intake during the milk restriction (125 ± 12 vs. 70 ± 19 g piglet^− 1 day^− 1; P = 0.08). Feed intake was improved by IS during the second week post-weaning (676 ± 17 vs. 497 ± 12 g piglet^− 1 day^− 1, P < 0.01), but differences were totally offset after the 7th week of age. Differences in average growth rate of litters on C and IS treatments did not attain statistical significance during the period of restriction and in the first week post-weaning. Litters on IS showed increased growth rate during the second week post-weaning (422 ± 31 vs. 289 ± 33 g piglet^− 1 day^− 1; P = 0.01), but slower daily gains from the 3rd week post-weaning to 60 day of age than litters on C treatment (371 ± 14 vs. 432 ± 15 g piglet^− 1 day^− 1; P < 0.05). Nevertheless, neither at weaning nor at 60 days of age average body weight of piglets differed between treatments (7.71 ± 0.31 vs. 7.94 ± 0.30 kg for C and IS, at 35 days of age, 15.62 ± 0.65 vs. 16.20 ± 0.62 kg, at day 60). The apparent digestibility of nutrients of the starter diet offered after weaning remained unaffected by the treatment, except for a trend for higher ApD of GE for the piglets on IS treatment (P = 0.08). ApD for CP and GE was 78.1 ± 0.6 and 78.8 ± 0.3%, respectively. No significant differences in the proportions of total viscera and gastrointestinal tract to empty body weight (EBW) were observed between C and IS piglets at weaning and 60 d of age. In conclusion, the increase in feed intake observed prior and early after weaning as a consequence of intermittent suckling during the last week of 35 d lactation had no effect on nutrient digestibility measured at two weeks after weaning and failed on improving Iberian piglet performance.     

Comparative study of electron microscopical techniques for the detection of scrapie-associated fibrils

Samples of cervical spinal cord and four anatomical regions of the brains of 12 sheep with natural scrapie and six control sheep were examined by electron microscopy, after the tissues had been stored at 4°C and −20°C. The tissues were tested for the presence of scrapie-associated fibrils by a centrifugal extraction technique and by a touch-grid technique. The touch-grid technique was no better than the centrifugal extraction technique for the detection of fibrils. Structures which could have been classified as tubulofilaments were detected in touch-grid preparations without detergent treatment. With the centrifugal extraction technique there was a significant reduction of the fibril scores in some of the tissue extracts stored at −20°C, but not in any of the extracts stored at 4°C. There was, however, a reduction in the fibril scores when the final extracted pellets were stored at 4°C. The stability of the fibrils on the test grids was unaffected by six months storage at room temperature but the clarity of their ultrastructure did deteriorate. Poor hydrophilic spread of the sample on the test grids did not have a significant effect on the fibril scores.     

Correlation between clinical signs of depth of anaesthesia and cerebral state index responses in dogs during induction of anaesthesia with propofol

The cerebral state index (CSI) is used for monitoring EEG and depth of anaesthesia. The objective of this study was to analyse the correlation between ocular reflexes, CSI and estimated propofol plasma concentrations (PropCP) in dogs during induction of anaesthesia with propofol.Fourteen dogs were premedicated with acepromazine 0.05 mg kg⁻¹ IM. Anaesthesia was induced with a 200 ml h⁻¹ propofol 1% constant infusion rate until loss of corneal reflex using RugLoop II software with Beths’ pharmacokinetic model to estimate PropCp.Palpebral reflex (PR) and the corneal reflex (CR) were tested every 30 s and classified as present (+) or absent (−), and eyeball position was registered as rotated ventromedialy (ERV) or centred (EC).Heart rate (HR), mean arterial pressure (MAP) and CSI values were analyzed from baseline before the beginning of propofol infusion (T0) until loss of CR; CSI and PropCp, CSI and anaesthetic planes, and PropCp and anaesthetic planes were compared using correlation analysis.PropCp reached 7.65 ± 2.1 μg ml⁻¹ at the end of the study. CSI values at T0 were 89.2 ± 3.8. Based on the observation of ocular reflexes and eyeball position, it was possible to define five anaesthetic planes: A (superficial) to E (deep), being A (PR+/CR+/EC), B (PR+/ERV/CR+), C (PR−/ERV/CR+), D (PR−/EC/CR+) and E (PR−/EC/CR−). There was a significant correlation between PropCp and the anaesthetic planes (R = 0,861; P < 0.01). No significant correlation was observed between CSI and the anaesthetic planes or between CSI and PropCp. MAP decreased significantly from T0 until loss of corneal reflex (from 98 ± 14 mmHg to 82 ± 12 mmHg); HR did not change significantly (from 101 ± 30 bpm to 113 ± 16 bpm).The CSI monitoring was not consistent with the clinical observations observed in the different stages of depth anaesthesia. This could limit the use of CSI for monitoring depth of anaesthesia with propofol.     

In vitro activity of danofloxacin, tylosin and oxytetracycline against mycoplasmas of veterinary importance

The activities of danofloxacin, a novel fluoroquinolone, and two other antimicrobials were determined in vitro against field isolates of seven Mycoplasma species of veterinary importance isolated from cattle, swine and poultry in five European countries. The minimum inhibitory concentrations (MIC) of danofloxacin, tylosin and oxytetracycline were determined against a total of 68 isolates. Danofloxacin showed excellent activity against isolates of all Mycoplasma species (range 0·008 to 0·5 μg ml⁻¹), but in some isolates there was evidence of reduced sensitivity to tylosin (range 0·008 to 2·0 μg ml⁻¹) and oxytetracycline (range 0·008 to over 16·0 μg ml⁻¹). Danofloxacin was more active than other antimicrobials against, M hyopneumoniae, M dispar and M bovigenitalium, and showed activity similar to that of tylosin against M bovis and M gallisepticum. Tylosin was the most active against M synoviae and M hyosynoviae. Generally, oxytetracycline showed the poorest activity, but was superior to tylosin against M bovigenitalium. A second (final) MIC reading was taken for all isolates 14 or 21 days after the initial reading, and MIC values rose during that time. However, the increase seen in danofloxacin values (typically one to two dilutions) was less than that seen for tylosin and oxytetracycline. It is concluded that danofloxacin is highly active in vitro against all of the Mycoplasma species tested, and thus shows great potential for the treatment of respiratory and other infections caused by Mycoplasma species in cattle, pigs and poultry.     

Effects of high environmental temperatures on physiological and nutritional status of prepubertal Holstein heifers

A series of studies were carried out to determine the effects of increasing environmental temperature (20 to 28 to 33 °C) at a constant (60%) relative humidity on the physiological responses, energy and nitrogen balance of prepubertal Holstein heifers (n = 4, initial body weight = 198 ± 3 kg). The relatively high environmental temperatures of 28 and 33 °C increased rectal temperature by 0.2 and 1.2 °C and increased respiration by 23 and 58 breaths per min, respectively. At 28 °C, dry matter intake was similar to that at 20 °C, whereas at 33 °C dry matter intake was lower (P < 0.10) by about 9%. However, the dry matter digestibility was higher (P < 0.05) at 33 °C than at 20 °C, hence the thermal treatments did not affect daily weight gain. At 33 °C blood urea nitrogen increased whereas hematocrit and plasma glucose concentrations decreased. At 33 °C energy and nitrogen intake were lower (P < 0.10), while energy and nitrogen digestibility were higher at 33 °C than at 20 °C. Urinary nitrogen was elevated at 33 °C resulting in lower nitrogen retention. Although, energy retention as fat did not differ (P > 0.10) among the treatments, energy retention as protein was lower (P < 0.05) at 33 °C than at 20 °C or 28 °C. These results confirmed that the effects of environmental temperature on prepubertal heifers were severe above 28 °C.     

Rumen degradation characteristics of sweet potato foliage and performance by local and crossbred calves fed milk and foliage from three cultivars

The study investigated rumen dry matter (DM) degradability characteristics in a completely randomized design and the effects of milk, sweet potato foliage (SPF) from three cultivars (A = TIS-87/0087; B = TIS-8164; C = TIS-2532.OP.1.13), dried brewers' grains (DBG) and cottonseed meal (CSM) as supplements to Panicum maximum (Panicum) for pre-weaned calves in randomized complete block designs. Diet 1 = milk + SPF-A foliage + Panicum, Diet 2 = milk + SPF-B foliage + Panicum, Diet 3 = milk + SPF-C foliage + Panicum, and Diet 4 = milk + DBG & CSM + Panicum (as control). Dry matter (130 ± 0.4 to 864 ± 3.9 g kg^− 1), ash (54 ± 4.2 to 173 ± 2.8 g kg^− 1 DM), OM (827 ± 4.2 to 946 ± 5.7 g kg^− 1 DM), N (7.4 ± 0.6 to 38.6 ± 1.4 g kg^− 1 DM), and NDF (439 ± 1.4 to 774 ± 8.5 g kg^− 1 DM) contents were highly significant (P < 0.01). In Trial I, 16 pre-weaned calves were used over 70 d with milk intake (34.8 ± 4.4 ml kg W^− 0.75 d^− 1), Panicum DMI (22.3 ± 2.77 g kg W^− 0.75 d^− 1), total DMI (35.7 ± 2.83 g kg W^− 0.75 d^− 1), and LWG (198 ± 44.6 g d^− 1) not significantly different (P > 0.05). Supplement DMI varied (P < 0.05) from 11.6 g kg W^− 0.75 d^− 1 in Diet 3 to 16.6 g kg W^− 0.75 d^− 1 in Diet 4. In Trial II, 16 pre-weaned local and crossbred calves were involved over 77 d with initial age of calves, Panicum intake, metabolic DMI, and LWG similar (P > 0.05) among crosses. Birthweight varied (P < 0.05) from 17.3 kg for N'Dama × Jersey crosses to 21.2 kg for White Fulani × Brown Swiss crosses. Supplement and total DMI ranged (P < 0.05) from 172 to 483 g d^− 1 for N'Dama × Jersey crosses to 233 and 674 g d^− 1 for non-inseminate or purebred calves, respectively. The LWG in the White Fulani × Brown Swiss and the N'Dama × Jersey calves were respectively 30% and 24% better, though not significantly, than purebred calves. In Trial III, rumen DM degradability characteristics of feeds in three N'Dama steers showed no significant differences (P > 0.05) in slowly degradable fraction (b) and rate of degradation of b (c). Soluble fraction (a), 48-h degradation, potential degradability (PD) and effective degradability (ED) varied significantly (P < 0.05) and were lowest in Panicum, but similar for foliage among the three sweet potato cultivars. Panicum fodder showed improvements in degradation characteristics with supplementation.     

Influence of methionine and dithioerythritol on sperm motility, lipid peroxidation and antioxidant capacities during liquid storage of ram semen

The aim of this study was to investigate the effects of methionine and dithioerythritol, added to the Tris extender, on ram sperm motility and LPO (lipid peroxidation) and antioxidant capacities during liquid storage up to 72 h at 5 °C. Ejaculates collected from five Merino rams, were evaluated and pooled at 37 °C. This study included two experiments. In experiment 1, each pooled ejaculate was divided into four equal aliquots and diluted (37 °C) with the base extender, containing 0 (control), 1, 2 and 4 mM methionine, at a final concentration of approximately 4 × 10⁸ sperms/ml (single step dilution), in a 15-ml plastic centrifuge tube. In experiment 2, dithioerythritol, at concentrations of 0 (control), 0.5, 1 and 2 mM, was used as an additive in the extender, and the procedure explained above was applied for the division of aliquots and the dilution of semen. Diluted semen samples were kept in glass tubes and cooled from 37 to 5 °C in a cold cabinet, and maintained at 5 °C. Sperm motility and LPO and total glutathione (GSH) and glutathione peroxidase (GPx) capacities were determined at 5 °C for periods of 0, 24, 48 and 72 h of liquid storage.The extender supplemented with 1 mM methionine led to higher motility percentages (77.0 ± 1.2%), in comparison to the control group (66.0 ± 4.9%), during 72 h of liquid storage (P < 0.05). As regards dithioerythritol, it did not statistically improve the motility rates for any of the storage times at 5 °C. In biochemical assays, differences in LPO levels between the groups with antioxidants and the control groups were not statistically significant. Compared to the control group, no significant difference was observed in GSH and GPx activities following the addition of methionine, during 72 h of storage. Total GSH and GPx activities did not increase significantly upon supplementation with 0.5 and 1 mM of dithioerythritol, compared to the control group, at any of the time points (P > 0.05). Dithioerythritol at 2 mM led (P < 0.01) to elevating GSH activity, compared to the control group, during 72 h of liquid storage. GPx activity was approximately 10 times higher for 2 mM of dithioerythritol (P < 0.001), compared to that of the control group at all time points.The question regarding the sustainability of sperm survival, LPO and antioxidant capacities following liquid storage of semen remains unanswered. Further studies are required for a better understanding of the biochemical changes and to obtain more information on the determination of lipid peroxidation and antioxidant capacities during cooled storage of ram semen.     

Effect of environmental factors on fertility of Holstein–Friesian cattle in Japan

We investigated the environmental factors in Japan, including meteorological conditions, on the fertility of a European cattle breed, Holstein–Friesian, by examining conception rates in different regions. First artificial insemination and associated conception details were recorded for 69,952 Holstein female cattle. In general, meteorological conditions vary considerably according to latitude in Japanese islands. Conception rates were higher in the Northern (above 37°N) than the Southern (below 37°N) region (61.3% vs. 53.3%). All the factors analyzed in the statistical model, including insemination year, region, month, AI technician, service sire and interaction between region and month, had significant effects on the conception rate. In the Southern region, conception rates were lower in the summer months (average temperature, 27.8 °C, and maximum temperature, 32.3 °C). However, this seasonal decline was not observed in the Northern region (average temperature, 23.7 °C, and maximum temperature, 28.4 °C). Regression analysis of conception rate in relation to temperature showed highly significant negative regression coefficients (− 0.66 to − 0.63% per °C; p < 0.001) in the Southern region, but non-significant coefficients in the Northern region. Humidity had a minimal effect on conception rate in both regions. Our data collectively suggest that 37°N latitude is a threshold that affects Holstein–Friesian conception rates in Japan.     

Genetic and phenotypic parameter estimates for growth traits in Boer goat

An understanding of influencing factors and genetic principles affecting the growth traits is needed to implement optimal breeding and selection programs. In this study, heritabilities (direct additive and maternal) of body weights at birth (BW0), 90 days (BW90) and 300 days (BW300) of age and average daily gains from birth to 90 days (ADG0-90), birth to 300 days (ADG0-300) and 90 days to 300 days (ADG90–300) of age in Boer goats were estimated on the basis of 1520 Boer goats at Boer Goat Breeding Station in Yidu, China, during 2002–2007. The parameters were estimated using a DFREML procedure by excluding or including maternal genetic or permanent maternal environmental effects, four analysis models were fitted in order to optimize the model for each trait. Influencing factors such as parity, litter size, kidding year and season, as well as sex of kids and some significant interactions among these factors were investigated as the fixed effects for the models. The results showed that the birth year and maternal genetic effects such as parity and litter size of dam were important determinants of the genetic parameter estimates for pre-weaning growth traits, and environmental effects such as birth year, season and sex of kids had some significant effect on post-weaning growth traits. The mean values and standard errors (SE) of direct additive heritability estimates calculated with the optimum model were 0.17 ± 0.07, 0.22 ± 0.08, 0.07 ± 0.07, 0.10 ± 0.08, 0.30 ± 0.12 and 0.08 ± 0.10 for BW0, BW90, ADG0-90, BW300, ADG0-300 and ADG90–300, respectively. For pre-weaning weights, correlation estimates between direct additive and maternal genetic (r_a–m) effect were high and negative ranging from − 0.74 to − 0.86.     

Comparison of carprofen and flunixin meglumine asadjunctive therapy in bovine respiratory disease

In an open, controlled, multi-centre clinical field trial, seven ‘naturally occurring’ outbreaks of acutefebrile (rectal temperature ≥ 39·5°C) respiratory disease in housed calves were treated with a single antimicrobial agent, and either the non-steroidal anti-inflammatory drug (NSAID) carprofen (n=95) or flunixin meghunine (n=92) on an alternate basis. Carprofen was administered as a single subcutaneous injection at a mean dosage of 1·4 mg kg⁻¹ (range 1·2 to 1·9 mg kg⁻¹) body weight on the first day and flunixin meglumine by intravenous injection at a mean dosage of 2·0 mg kg⁻¹ (range 1·2 to 2·6 mg kg⁻¹) body weight on the first 3 consecutive days. All calves were examined clinically immediately prior to initial treatment and on three occasions up to 1 week after the end of treatment. There were no statistically significant differences between NSAID groups in reduction of clinical parameters between examinations, or in overall efficacy. This trial demonstrated that a single dose of carprofen was equally effective as three daily closes of flunixin meglumine as adjunctive therapy to antimicrobial treatment in acute respiratory disease in calves.     

Reference values on hematologic parameters of the Brazilian donkey (Equus asinus) breed

Thirteen hematologic measurements were performed on 38 healthy donkeys of the Brazilian breed (32 females and 6 males) aged 3 to 19 years. Mean ±SD (minimum-maximum) values were as follows: red blood cells (RBC) 6.82 ± 0.67 (5.46−8.17) × 10⁶/μL; packed cell volume (PCV) 37.63 ± 2.76 (32.00−44.00) %; hemoglobin (Hb) 12.87 ± 0.98 (10.70−14.50) g/dL; mean corpuscular volume (MCV) 55.45 ± 4.06 (48.90−62.70) fL; mean corpuscular hemoglobin (MCH) 18.85 ± 1.14 (17.40−21.60) pg; mean corpuscular hemoglobin concentration 34.20 ± 1.24 (31.50−36.40) g/dL; white blood cells (WBC) 8.22 ± 1.49 (4.60−11.50) × 10³/μL; bands 1.77 ± 2.00 (0.00−9.00) %; segmented neutrophils 41.18 ± 5.98 (30.50−53.20) %; lymphocytes 50.53 ± 6.25 (35.30−63.50) %; monocytes 1.57 ± 1.30 (0.00−4.60) %; eosinophils, 4.64 ± 2.17 (1.00−10.00) %; basophils 0.33 ± 0.58 (0.00−2.90) %. It was demonstrated that values of some blood parameters of the Brazilian donkey breed were similar to results obtained for other donkey breeds. The results of this study serve as reference ranges for donkey populations and can be useful for health control, which in turn helps in the diagnosis and prognosis of diseases.

Introduction

Blood examination has been performed for several reasons: as a screening procedure to assess general health; as an adjunct to patient's infection; and to evaluate the progress of certain disease states.[1] However, there are important differences in physiology, behavior, and management that influence the common diseases encountered in donkeys. Successful diagnosis and treatment often depend on recognizing these differences. [2] Unfortunately, a limited number of observations have been reported on the hematologic values for donkey breeds and populations and these studies are far from complete. [3, 4, 5, 6, 7, 8 and 9] Hematologic variation values for donkey breeds and populations should be associated with the age, sex, and the time of sampling in relation to exercise, geographic, and nutritional factors. Perhaps some of the variations observed among different authors were also associated with different techniques and methods. [4]Apart from the investigations by Perdigão de Oliveira et al,[3] Gacek et al, [10] and Mori et al, [11] we could find no published record of blood values of the Brazilian donkey breed. The aim of this investigation was to determine reference ranges for hematologic analyses in the Brazilian donkey breed to establish a baseline for further scientific and clinical use.

Materials and methods

The material for the present study consisted of 38 adult donkeys of the Brazilian breed (32 females and 6 males), ranging between 3 and 19 years of age (mean ±SD: 8.3 ± 3.5 years), from the Estação Experimental de Colina do Instituto de Zootecnia da Secretaria de Agricultura do Estado de São Paulo, and kept under similar feeding and management conditions. All animals were apparently healthy, and they were handled carefully to reduce any possible effects of stress on the parameters analyzed.Blood samples were draw from the jugular vein into 5 mL evacuated glass tubes containing EDTA as anticoagulant. Blood smears were prepared immediately after being collected from whole blood and then were air-dried. The collected blood samples were immediately stored at 4°C and processed within 6 hours.RBC and WBC counts were performed using an electronic counter (Serono Baker). Hb concentration was determined by the cyanmethemoglobin method. PCV was determined after the blood had been transferred to microhematocrit tubes and centrifuged at 10,000 g for 5 minutes. MCV, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration were calculated from PCV, Hb concentration, and RBC count.[1] Blood smears were stained with modified May-Grunwald Giemsa stain for determination of the differential WBC count. At least 200 WBCs were counted for differential WBC determinations.All analyses were performed within the Departamento de Clinica Médica da Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo.Data analysis was performed using a statistical software (Graph Pad InStat version 3.01, 32 bit for Windows 95/NT). Each parameter was tested for normality applying the Kolmogorov and Smirnov methods. The reference ranges for the hematologic analyses were given as mean ±SD and the interval from minimum and maximum values.Unpaired t-tests were used to determine the effect of sex (female versus male) on hematologic values, for data normally distributed. If data did not seem to be normally distributed, non-parametric tests (Mann-Whitney U test) were used. The level of statistical significance was set at P < .05.

Results

Reference ranges of hematologic constituents of the blood of the Brazilian donkey breed determined in the current study are shown in Table 1 and Table 2. Most of the values had Gaussian distribution (P < .10). Only basophils did not seem to be normally distributed (P < .05). Comparisons of hematologic ranges of the Brazilian donkeys with other donkey breeds and populations are shown in Table 1 and Table 2.     

Lincomycin and spectinomycin in the treatment of breeding rams with semen contaminated with ureaplasmas

Ureaplasma species were isolated from semen samples collected sequentially from one Awassi and three Assaf breeding rams. Each ram was injected subcutaneously with an aqueous solution of lincomycin and spectinomycin for five consecutive days at a dose equivalent to 4·5 mg kg⁻¹ lincomycin and 9·0 mg kg⁻¹ spectinomycin daily. Serum and semen samples were collected at intervals during the treatment and assayed for lincomycin. No Ureaplasma species were isolated from semen samples collected during the course of the treatment and at intervals for 17 days after the last treatment. The concentration of lincomycin in semen ranged from 0·51 μg ml⁻¹ four hours after treatment to 0·08 μg ml⁻¹ 24 hours after treatment, and these levels were three to nine times higher than the corresponding serum concentrations.     

Blood lactate disappearance after maximal exercise in trained and detrained horses

The influence of training on blood lactate concentrations during treadmill exercise and a 40-minute inactive recovery period was examined in seven trained and seven detrained thorough-bred horses. Lactate concentrations were measured in venous blood collected at the end of each exercise state, and at intervals for 40 minutes afterwards. Measurements were made of maximum oxygen uptake (V̇O_2max, ml kg⁻¹ min⁻¹), VLA4 (velocity at which blood lactate concentration was 4 mmol litre⁻¹); LA8 (lactate concentration [mmol litre⁻¹] during exercise at 8 m sec⁻¹), peak lactate (highest lactate concentration after exercise), LA40 (lactate concentration 40 minutes after exercise), the time of peak lactate concentration (minutes after exercise) and the rate of disappearance of blood lactate (Rt_d). The trained horses had a significantly lower LA8 (2·1 ± 0·1 vs 6·5 ± 1 mmol litre⁻¹, P<0·01), higher VLA4 (9·8 ± 0·2 vs 5·8 ± 0·6 m sec⁻¹, P<0·01) and higher V̇0_2max (156·3 ± 3·8 vs 107·1 ± 3·9 ml kg⁻¹ min⁻¹, P<0·001). The value of Rt_d and the time of peak lactate concentration were not significantly different.     

Resistance of Santa Ines and crossbred ewes to naturally acquired gastrointestinal nematode infections

This trial was carried out in Piracicaba, São Paulo State, Brazil, to comparatively evaluate the degree of resistance to naturally acquired gastrointestinal nematode infections in sheep of the following genetic groups: purebred Santa Ines (SI), SI crossbred with Dorper (DO × SI), Ile de France (IF × SI), Suffolk (SU × SI), and Texel (TE × SI). Fifteen ewes from each group were raised indoors until 12 months of age. At this age, they were moved to pasture that was naturally contaminated by nematode infective larvae and were evaluated from December to May, 2007. Rainfall ranged from 267 mm in January to 37 mm in April. Maximum and minimum mean temperatures ranged from 32.5 °C to 19.0 °C in March and from 25.9 °C to 12.8 °C in May. There was an increase in the mean number of eggs per gram of feces (EPG) after animals were placed on pasture with significant difference between the SI (80 EPG) and IF × SI (347 EPG) groups in January; and the DO × SI (386 EPG) and TE × SI (258 EPG) groups in May. The highest mean fecal egg count (FEC), 2073 EPG, was recorded for the TE × SI group in February. All groups showed a progressive reduction in body weight throughout the experiment of 12.0% (TE × SI) to 15.9% (SU × SI). In general, the animals with the highest FEC presented the lowest packed cell volumes (PCV); the highest correlation coefficient between FEC × PCV occurred in the SU × SI sheep in January (r = −0.70; P < 0.01). Similarly, there was an inverse relationship between FEC and blood eosinophil values, with the highest correlation coefficient in the TE × SI sheep in February (r = −0.64; P < 0.05). Immunoglobulin G (IgG) levels against Haemonchus contortus antigens increased in all groups as a result of the exposure to parasites and remained relatively constant until the end of the study, with the exceptions of SU × SI and TE × SI, which showed a rise in IgG levels during the last sampling that coincided with a reduction in mean FEC. In conclusion, crossbreeding Santa Ines sheep with any of the breeds evaluated can result in a production increase and the maintenance of a satisfactory degree of infection resistance, especially against H. contortus and Trichostrongylus colubriformis, the major nematodes detected in this flock.     

Comparison of Caudal Epidural Anesthesia with Lidocaine-distilled Water and Lidocaine-MgSO4 Mixture in Horses

This study was performed to compare the onset and duration of analgesia produced by either a lidocaine−MgSO₄ or lidocaine−distilled water combination administration in the caudal epidural space of horse. Seven healthy adult horses, aged 11.7 ± 1.4 years (mean ± SD), body weight (kg) 567 ± 32.5 (mean ± SD), were selected for this study. Caudal epidural anesthesia was produced in all horses by administering 2% lidocaine (0.22 mg/kg) diluted in 1 mL distilled water and repeated with 2% lidocaine (0.22 mg/kg) diluted in 1 mL 10% MgSO₄ 2 weeks later. Time to onset (minutes), duration (minutes), and cranial spread of epidural analgesia were recorded. Heart rate (HR), respiratory rate (RR), and body temperature (°C) were recorded. Measurements were taken at 0 (as a baseline value before epidural administrations) and at 5, 10, 15, 30, 60, and 75 minutes after the epidural administrations of each treatment. Statistical analyses included paired Student t test and analysis of variance (computer program SPSS, Analytical Software, version 15.00). Statistical significance was set at P < .05. Onset of analgesia was significantly different (P < .001) between lidocaine-distilled water (2.38 ± 0.47 minutes) and lidocaine−MgSO₄ (4.62 ± 0.54 minutes). Duration of analgesia after lidocaine−MgSO₄ (186.0 ± 7.0 minutes) was longer than lidocaine-distilled water (54.5 ± 7.3 minutes). No significant differences were recorded for HR, RR, and body temperature in comparison with baseline values for each group. Using the lidocaine−MgSO₄ combination for obstetric and surgical procedures could commence relatively soon after epidural injection and could be completed without readministration of anesthetic agent.     

Effects of inhibition of nitric oxide synthase on systemic arterial pressure and renal vascular resistance in cats

These studies were undertaken to examine the systemic and renal effects of the pharmacological inhibition of endothelium-derived nitric oxide (EDNO) in cats. In six healthy cats, the intravenous infusion of nitro-L-arginine at a dose of 100 μg kg⁻¹ bodyweight min⁻¹ resulted in a marked increase (P<0·001) in mean arterial pressure from the control value of 116·7 ± 4·6 mmHg to 154·2 ± 6·8 mmHg and an increase (P<0·05) in renal vascular resistance from the control value of 3·69 ± 0·33 mmHg min ml⁻¹ to 6·83 ± 1·15 mmHg min ml⁻¹. The increase in renal vascular resistance was generalised, with comparable increments in preglomerular and postglomerular vascular resistance. Mean values for glomerular capillary pressure (61·1 ± 61·9 vs 1·9 ± 1·6 mmHg), calculated from the sum of arterial colloid osmotic pressure plus proximal tubule stop-flow pressure, did not change in response to the infusion of nitro-L-arginine. However, there was a marked reduction in renal blood flow (29·4 ± 3·1 to 16·9 ± 2·3 ml min⁻¹, P<0·01) and glomerular filtration rate (5·22 ± 0·57 to 3·52 ± 0·45 ml min⁻¹, P<0·01). These results provide evidence that EDNO plays an important role in the basal regulation of systemic arterial blood pressure and renal haemodynamics in cats.     

Osmotic fragility of erythrocytes in clinically normal dogs and dogs infected with parasites

The osmotic fragility of the erythrocytes was measured in blood samples collected from randomly selected healthy and infected dogs at a dogs' rescue shelter. The dogs were classified into six groups on the basis of the final diagnoses from clinical, post mortem and laboratory findings. The minimum (less than 5 per cent) and maximum (more than 90 per cent) haemolysis of the erythrocytes of the clinically normal dogs (group 1), occurred in 0·60 per cent and 0·30 per cent solutions of sodium chloride (NaCI). For the non-anaemic hookworm-infected dogs (group 2a) the respective values were 0·8 per cent and 0·4 per cent NaCl, and for the anaemic hookworm-infected dogs (group 2b) they were 0·85 per cent and 0·5 per cent NaCl, respectively. The erythrocytes from dogs with Babesia canis (group 3), concurrent hookworm and B canis (group 4) and Ehrlichia canis infections (group 5) had minimum haemolysis in 0·75 per cent NaCl and maximum haemolysis at between 0·20 per cent and 0·35 per cent NaCI solutions. The derivative fragiligrams for groups 2a, 2b, 3 and 4 were shifted to the left, whereas the fragiligram for group 5 was similar to that for the clinically normal dogs (group 1). The left shift for the hookworm-infected dogs was due to the increased osmotic fragility of a minor sub-population of the erythrocytes, but for the dogs, infected with B canis major sub-populations of the erythrocytes had an increased osmotic fragility.     

Life-history parameters of Culicoides (Avaritia) imicola Kieffer in the laboratory at different rearing temperatures

This laboratory study investigates the sub-adult developmental cycle of field collected Culicoides (Avaritia) imicola Kieffer (Diptera; Ceratopogonidae). The period required from blood-feeding field-collected females to the production of progeny adults occupied 34–56 days at 20 °C, 15–21 days at 25 °C and 11–16 days at 28 °C, demonstrating clear temperature dependence. When reared at 28 °C, C. imicola demonstrated higher variability in fecundity (between 2.4 and 20.6 eggs/female) and lower hatching rates (50.0–62.2%), although larval survival rates to pupation were low at all temperatures (20–30%). Similarly, the mean emergence rate from pupae was the highest at lower temperatures. These results highlight the difficulty in establishing and maintaining a laboratory colony of this species from field-collected material and results are discussed in reference to future research directions that may aid this process.