The effect of medetomidine and its antagonism with atipamezole on stress-related hormones, metabolites, physiologic responses, sedation, and analgesia in goats

Six 3‐year‐old goats (three males and three females) weighing 60.0 ± 18 kg (mean ± SD) were used to investigate the effect of medetomidine (MED; 20 µg kg^?1 IV) and its antagonism with atipamezole (ATI; 100 µg kg^?1 IV) on physiologic responses (heart rate (HR; beats minute^?1), respiratory rate (RR; breaths minute^?1), electrocardiogram (ECG), rectal temperature (T; °C), blood pressure (oscillometric; mm Hg), sedation (SED), posture (REC), analgesia (ALG), and stress‐related hormonal and metabolic responses (epinephrine and norepinephrine (high performance liquid chromatography with electrochemical detection), cortisol (COR; µg dL^?1; radioimmunoassay), glucose (GLU; mg mL^?1; enzymatic colorimetric assay), and free fatty acids (modified enzymatic colorimetric assay)); each goat received ATI or SAL in random order separated by 1 week. Jugular catheters were placed for drug administration and blood sampling (10–12 mL sample^?1) using a lidocaine skin block (20 mg) 2 hours prior to beginning of each trial; during this trial, goats breathed room air. Physiologic parameters were measured, SED, REC, and ALG were scored, and blood samples were collected from jugular catheters at baseline (time = ?30 minutes), 5 minutes post‐MED administration (time = ?25 minutes), 25 minute post‐MED administration and immediately prior to antagonism (time = 0 minute), and at 5, 30, 60, and 120 minutes after administering ATI or SAL. ALG was tested by clamping the withers and metacarpus with hoof testers fitted with a force transducer to measure applied isometric force (lb) (a technique used previously in goats to evaluate analgesia). Continuous variables were analyzed by Repeated Measures analysis of variance (anova ); categorical data were analyzed using a Friedman Repeated Measures anova on ranks. A p‐value of <0.05 was considered significant. If a significant difference was found, a Dunnett's pair‐wise comparison of means was conducted. Differences between ATI and SAL were examined at 5, 30, 60, and 120 minutes using a paired t‐test with a Bonferroni correction. Administration of MED resulted in a decrease in T (38.7 ± 0.3 to 34.5 ± 0.4 °C), HR (78 ± 19 to 55 ± 9), and RR (31 ± 12 to 14 ± 5) over time; an increase in mean arterial blood pressure (90 ± 19 to 132 ± 23), COR (0.254 ± 0.125 to 4.327 ± 1.233), and GLU (82.0 ± 13.2 to 255.9 ± 38.9); and changes in SED (alert to marked sedation), REC (standing to recumbent), and ALG (metacarpus = 5 ± 2 to 14 ± 0; withers = 3 ± 2 to 14 ± 0). GLU was 62–70% higher at 60 and 120 minutes and COR was 336% higher after SAL than after ATI at 120 minutes; at 30, 60, and 120 minutes, T was 4–10% higher after ATI than SAL. There were no other significant differences. REC, SED, and ALG were antagonized after ATI. ATI did not antagonize the effect of MED on HR, RR, or MAP, but stabilized T and antagonized the increase in GLU and COR.     

Evolution des hydrates de carbone non structuraux chez la morelle jaune (Solatium elaeagnifolium Cav.)

Les teneurs en hydrates de carbone non structuraux (TNC) des racines, collets et tiges des in-dividus de la morelle jaune (Solarium elaeagnifolium Cav.) issue des bordures, champ de cotonnier et verger d'oliviers ont été déter-minées mensuellement pendant une année. Les racines et, dans une certaine mesure, les collets ont été les organes où les réserves glucidiques étaient les plus importantes. Ces glucides ont atteint leur niveau le plus bas au moment de la formation des boutons floraux. La reconstitution des réserves en TNC a lieu entre la floraison et la maturation des fruits sur une durée de 2, 4 et 5 mois pour les individus issus du champ de cotonnier, des bordures et du verger d'oliviers, respec-tivement. L'évolution des TNC est plus influencée par le stade phénologique de l'espèce que par rhumidité et la température du sol. Les implications de ces réquitals pour définir une stratégic de lutte centre la morelle jaune sont également discutées. Seasonal changes in non-structural carbohydrates in silver-leaf nightshade (Solanum elaeagnifolium Cav.) The levels of non-structural carbohydrates (TNC) in the roots, root collar and stems of S. elaeagnifolium collected from field margins, cotton fields and olive plantations were determined monthly over a period of 1 year. The roots, and to a certain extent the root collar, were the organs with the largest carbohydrate reserves. The carbohydrate level was lowest at the time of flower bud formation. There was a build-up of TNC reserves between flowering and fruit maturation over periods of 2, 4 and 5 months from plants growing in cotton fields, field margins and olive plantations respectively. Changes in TNC are influenced more by the phenological stage of the plant than by soil humidity or temperature. The implications of these findings in defining a control strategy for this weed are discussed. Saisonale Einlagerung von Kohlenwasserstoffen beim Ölweidenblättrigen Nachtschatten (Solanum eleagnifolium Cav.) Die Gehalte unstrukturierler Kohlenwasser-stoffe (TNC) des Wurzeln, des Wurzelhalses und des Sprosses von Solanum elaeagnifolium Cav. von Feldrainen, Baumwollfeldern und Olivengärten wurden monatlich über l Jahr hin bestimmt. Die Wurzeln und in bestimmten Maβe der Wurzelhals waren die Pflanzenteile, in denen die Kohlenwasserstoffe die wichtigsten Re-servesubstanzen waren; sie hatten ihr nie-drigstes Niveau zur Blütenbildung. Der Wiederaufbau dieser Reservestoffe zwischen der Blüte und der Fruchtreife dauerte bei den Pflanzen auf den Baumwollfeldern, den Feldrainen und den Olivengärten 2, 4 bzw. 5 Monate. Die Kohlenhydratbildung wurde mehrnach den Entwicklungsstadienals durch Boden feuchte und-temperatur beeinflußt. Die Aspekte dieserUntersuchungsergebnisse für die Bekämpfung dieses Unkrauts werden diskutiert.     

Studies on the biology of black mould (Aspergillus niger) on temperate and tropical onions. 2. The effect of treatments on the control of seedborne A. niger

Treatment of A. niger -inoculated onion seed with benomyl dust (1 g a.i./kg), or a foliar spray of thiram (0·4% a.i./ha) applied to plants grown from inoculated seed under temperate (UK) conditions reduced the incidence of A. niger in harvested crops. Treatment of naturally contaminated Sudanese onion seed with a benomyl + thiram mixture at a rate of 2·5 + 2·5 g a.i./kg or soaking the seed in hot water (15 min at 60°C) reduced the incidence of black mould on bulbs grown in the Sudan in field soil that had not previously been used for onion production. The seed treatments were less effective in crops produced in fields regularly used for onion production. However, incubation of harvested bulbs in moist chambers showed that damage to the internal storage tissue of onion bulbs caused by A. niger was reduced by seed treatment.     

Genetic analysis of partial resistance to bacterial leaf streak (Xanthomonas campestris pv. cerealis) in wheat

Genetic variability of partial resistance to bacterial leaf streak was investigated in hexaploid winter wheat ( Triticum aestivum. ), using 16 parental genotypes and 48 pure lines (F10) derived from a composite cross programme. Two experiments were undertaken in a controlled growth chamber. Seeds of all genotypes were grown under controlled conditions using a randomized block design with three replications. Each replication consisted of a row of 20 seedlings of each parent and pure line. An Iranian strain of bacterial leaf streak was used for the inoculation of 12-day-old seedlings. In a third experiment, eight genotypes from parents and F10 pure lines representing a large variability for partial resistance were inoculated with four other Iranian strains of bacterial leaf streak. A large genetic variability was observed amongst the 64 genotypes for partial resistance to the disease. Partial resistance heritability estimates were rather high (70%), indicating that the resistance factors may be transmitted by crossing. Amongst all genotypes investigated, 'DC²-30-N2' and 'IBPT-66' displayed the highest partial resistance to the disease. Significant correlations between strains in the third experiment show that a genotype resistant or susceptible to one strain will have similar reactions with other strains. No significant genetic gain was observed for partial resistance in the best pure line of the 48 lines studied, when compared with the best parental line. Increasing the number of pure lines is likely to result in the identification of genotypes that might prove to be more resistant.     

Endometrial nitric oxide synthase activity in mares susceptible or resistant to persistent breeding‐induced endometritis and the effect of a specific iNOS inhibitor in vitro

Emerging research suggests that the nitric oxide system may play a role in persistent breeding‐induced endometritis (PBIE) in the mare. Differences in uterine nitric oxide (NO) levels between mares susceptible or resistant to PBIE and a dose‐dependent inhibitory effect of NO on uterine contractility have been demonstrated. The objectives of this study were to investigate the difference in total nitric oxide synthase (NOS) activity of the endometrium between susceptible and resistant mares and the effect of a specific inducible nitric oxide synthase (iNOS) inhibitor on the endometrial NOS activity in vitro. Six susceptible and six resistant mares were selected based on preset criteria and the results of an intrauterine challenge with killed spermatozoa during oestrus. Endometrial biopsy samples were collected 24 hr post‐challenge and cultured at 37°C for 24 hr in L‐arginine supplemented minimum essential medium with or without a specific iNOS inhibitor (1,400 W dihydrochloride, 1 mM). The medium and the cultured endometrial tissue were collected after 24 hr of culture and assayed for NO and total protein, respectively. Total NO content of the medium, normalized to endometrial tissue wet weight or total protein, was used as a measure of endometrial NOS activity. Non‐parametric tests were applied for statistical analysis. Susceptible mares had significantly greater endometrial NOS activity than resistant mares. The iNOS inhibitor treatment significantly reduced NOS activity in endometrial samples derived from susceptible and resistant mares. These findings provide a basis for in vivo testing of specific iNOS inhibitors as preventative or therapeutic options for PBIE in mares.     

Facial eczema management protocols used on dairy farms in the North Island of New Zealand and associated concentrations of zinc in serum

AIMS: To describe and evaluate the current practices used to manage and prevent facial eczema (FE) in North Island dairy herds, and determine the within-herd prevalence of cows with elevated activities of gamma glutamyl transferase (GGT), and with concentrations of Zn in serum <18?μmol/L.

METHODS: Between January and May 2014, 105 herd managers from throughout the North Island of New Zealand were invited to participate in the study when regional spore counts for Pithomyces chartarum started to rise towards 30,000 spores/g pasture. Managers selected 10 representative cattle that were weighed and blood-sampled by the herd veterinarian. Blood samples were analysed for concentrations of Zn in serum and GGT activity. Pasture samples were also collected and submitted for spore count estimation. Finally a survey of farm management practices relating to prevention of FE was completed by the herd manager. A mixed-effects logistic regression model was used to determine associations between herd-level and cow-level explanatory variables and the probability of a cow having a concentration of Zn in serum <18?µmol/L.

RESULTS: Of the 1,071 cows tested, 79 (7.3 (95% CI=5.8–9.0)%) had GGT activity in serum >300?IU/L, and 35/106 (33 (95% CI=24.2–42.8)%) herds had ≥1 of the 10 cows sampled with GGT activity >300?IU/L. Of the 911 cows that were being treated with Zn, concentrations of Zn were between 18–35?μmol/L in 398 (43.6 (95% CI=40.4–46.9)%) cows, were >35?μmol/L in 32 (3.5 (95% CI=2.4–4.1)%) cows, and <18?μmol/L in 479 (52.6 (95% CI=49.3–55.9)%) cows. After adjusting for the confounding effect of region, the odds of a cow having concentrations of Zn in serum <18?μmol/L were 5.5 (95% CI=1.1–29) times greater for cows supplemented with zinc in water compared with those supplemented by drenching. Of the 105 herd managers, 103 (98%) stated that they had access to regional spore count data, but only 35/105 (33%) reported that they measured spore counts on their own farm. Overall, 98/105 (93%) managers reported that they had some form of FE management programme in place. Fungicides were used on their own or in combination with zinc treatments in 10 herds, ZnSO₄ in water troughs was used in 68 herds, oral drenching with ZnO in nine herds, and ZnO supplied in-feed in 26 herds. Estimated daily dose rates of zinc were less than that required to treat a 400?kg cow on 42/68 farms that administered ZnSO₄ in the water or ZnO as a drench.

CONCLUSION AND CLINICAL RELEVANCE: This study has shown that FE management on dairy farms in the North Island of New Zealand could be substantially improved. It is likely that improved FE management would occur if herd managers were provided with more feedback on the success (or otherwise) of their FE management programmes.     

The influence of lime and nitrogen fertilisers on spore counts of Pithomyces chartarum in pasture

AIMS: To determine whether the application of lime or nitrogen to pasture affected the spore counts of Pithomyces chartarum.

MATERIALS AND METHODS: The lime application studies were undertaken on a spring-calving, pasture-based, commercial dairy farm near Te Awamutu, New Zealand. On 6 November 2012, five randomly selected paddocks were split into three equal sections. In two of the sections, lime was applied at either 1.5 or 2.5?t/ha, and the central section was left as an untreated control. Each section was sampled for spore counting weekly from 16 January to 15 May 2013.

Starting in January 2013, five other randomly selected paddocks were monitored for spore counts. On 20 March 2013 the average spore counts in three paddocks were >100,000 spores/g of pasture. These paddocks were then divided into three equal sections and lime was applied as described above. Spore counting in each section continued weekly until 15 May 2013.

The nitrogen application study was carried out on three commercial dairy farms near Te Awamutu, New Zealand. Two randomly selected paddocks on each farm were divided into three equal sections and, on 20 December 2012, nitrogen in the form of urea was applied at either 50 or 80?kg urea/ha to two of the sections; the central section remained as an untreated control. Each section was sampled for spore counting weekly from 16 January to 15 May 2013.

RESULTS: Following pre-summer lime application, treatment at 1.5 or 2.5?t/ha did not affect spore counts over time compared with the control section (p>0.26). Similarly following autumn lime application, treatment at 1.5 or 2.5?t/ha did not affect spore counts over time compared with the control section (p>0.11). Following nitrogen application median spore counts remained <20,000 spores/g pasture throughout the trial period and there was no effect of treatment on spore counts over time (p>0.49).

CONCLUSION: This study found that application of lime before the risk period for facial eczema, in November, application of lime after a spore count rise, in March, or urea application in December did not affect changes in number of spores produced by P. chartarum.

CLINICAL RELEVANCE: This study does not support previous suggestions that fertilising pasture with lime or urea could alter the spore counts of P. chartarum. Fertiliser use does not provide an alternative to, or support, conventional methods of facial eczema control such as zinc prophylaxis or treatment of pasture with fungicides.     

Effects of IGF‐1 on In Vitro Culture of Bovine Preantral Follicles are Dose‐Dependent

This study aimed at assessing the effect of different concentrations of the growth factor similar to insulin 1 (IGF‐1) in the development, survival and ultrastructure of the bovine preantral follicles cultured in situ. Fragments of bovine ovarian cortical tissue were cultured during 1 and 7 days in 1 ml of α‐MEM⁺, supplemented with different concentrations of human recombinant IGF‐1 (0, 30, 70 and 100 ng/ml), in an incubator at 37°C and 5% of CO₂ in 24‐well plates with total replacement of the medium every 2 days. Non‐cultured ovarian fragments (control) and ovarian fragments cultured during 1 and 7 days were processed for classic histology, mechanical isolation and electron transmission microscopy (ETM). Parameters such as normality, viability, activation, development, diameter and ultrastructure were evaluated. All statistical analyses were carried out using sas Version 9.2. The results showed that the percentage of follicles morphologically normal in the IGF‐1 30 ng/ml treatment was similar to the fresh control (p > 0.05) both on the day 1 and on the day 7 of in vitro culture. In the viability analysis, the cultured treatments maintained the percentage of viable follicles during the entire culture period (p > 0.05). After 7 days of culture, the IGF‐1 30 ng/ml treatment showed higher percentages of developing follicles (48.33%) than those of the fresh control (22.22%) and the cultured treatments (p < 0.05). Also, after 7 days of culture, IGF‐1 30 ng/ml presented a higher follicular diameter when compared to the control and other concentrations of IGF‐1 tested. Ultrastructurally, the non‐cultured control and IGF‐1 30 ng/ml, after 7 days of culture, showed conserved oocytes, nuclei and organelles. Hence, it is concluded that IGF‐1 30 ng/ml was the most efficient concentration for the development of bovine preantral follicles cultured in vitro.     

Characterization of the pharmacokinetic disposition of levofloxacin in stallions after intravenous and intramuscular administration

The target of the present study was to investigate the plasma disposition kinetics of levofloxacin in stallions (n = 6) following a single intravenous (i.v.) bolus or intramuscular (i.m.) injection at a dose rate of 4 mg/kg bwt, using a two‐phase crossover design with 15 days as an interval period. Plasma samples were collected at appropriate times during a 48‐h administration interval, and were analyzed using a microbiological assay method. The plasma levofloxacin disposition was best fitted to a two‐compartment open model after i.v. dosing. The half‐lives of distribution and elimination were 0.21 ± 0.13 and 2.58 ± 0.51 h, respectively. The volume of distribution at steady‐state was 0.81 ± 0.26 L/kg, the total body clearance (Cl_tot) was 0.21 ± 0.18 L/h/kg, and the areas under the concentration–time curves (AUCs) were 18.79 ± 4.57 μg.h/mL. Following i.m. administration, the mean t_1/2el and AUC values were 2.94 ± 0.78 h and 17.21 ± 4.36 μg.h/mL. The bioavailability was high (91.76% ± 12.68%), with a peak plasma mean concentration (C_max) of 2.85 ± 0.89 μg/mL attained at 1.56 ± 0.71 h (T_max). The in vitro protein binding percentage was 27.84%. Calculation of efficacy predictors showed that levofloxacin might have a good therapeutic profile against Gram‐negative and Gram‐positive bacteria, with an MIC ≤ 0.1 μg/mL.