Pharmacokinetics of articaine hydrochloride and its metabolite articainic acid after subcutaneous administration in red deer (Cervus elaphus)

AIM: To develop and validate a simple and sensitive method using liquid chromatography-mass spectrometry (LC-MS) for quantification of articaine, and its major metabolite articainic acid, in plasma of red deer (Cervus elaphus), and to investigate the pharmacokinetics of articaine hydrochloride and articainic acid in red deer following S/C administration of articaine hydrochloride as a complete ring block around the antler pedicle.

METHODS: The LC-MS method was validated by determining linearity, sensitivity, recovery, carry-over and repeatability. Articaine hydrochloride (40?mg/mL) was administered S/C to six healthy male red deer, at a dose of 1?mL/cm of pedicle circumference, as a complete ring block around the base of each antler. Blood samples were collected at various times over the following 12 hours. Concentrations in plasma of articaine and articainic acid were quantified using the validated LC-MS method. Pharmacokinetic parameters of articaine and articainic acid were estimated using non-compartmental analysis.

RESULTS: Calibration curves were linear for both articaine and articainic acid. The limits of quantifications for articaine and articainic acid were 5 and 10?ng/mL, respectively. Extraction recoveries were >72% for articaine and >68% for articainic acid. After S/C administration as a ring block around the base of each antler, mean maximum concentrations in plasma (C_max) of articaine were 1,013.9 (SD 510.1) ng/mL, detected at 0.17 (SD 0.00) hours, and the C_max for articainic acid was 762.6 (SD 95.4) ng/mL at 0.50 (SD 0.00) hours. The elimination half-lives of articaine hydrochloride and articainic acid were 1.12 (SD 0.17) and 0.90 (SD 0.07) hours, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE: The LC-MS method used for the quantification of articaine and its metabolite articainic acid in the plasma of red deer was simple, accurate and sensitive. Articaine hydrochloride was rapidly absorbed, hydrolysed to its inactive metabolite articainic acid, and eliminated following S/C administration as a ring block in red deer. These favourable pharmacokinetic properties suggest that articaine hydrochloride should be tested for efficacy as a local anaesthetic in red deer for removal of velvet antlers. Further studies to evaluate the safety and residues of articaine hydrochloride and articainic acid are required before articaine can be recommended for use as a local anaesthetic for this purpose.     

Feeding fodder beet (Beta vulgaris L.) with either barley straw or pasture silage to non-lactating dairy cows

AIMS: To determine the suitability of diets containing either approximately 85% fodder beet (Beta vulgaris L.) with barley straw or 65% fodder beet with pasture silage when fed to non-lactating dairy cows, by measuring intakes, digestibility, rumen function including microbial growth, and N excretion.

METHODS: Holstein-Friesian cows fitted with permanent rumen fistulae were fed either 65% fodder beet with pasture silage (Silage; n=8) or 85% fodder beet with barley (Hordeum vulgare L.) straw (Straw; n=8) in an indoor facility over a 9-day period, for measurement of intakes, digestibility, rumen function and urine production. The cows were adapted to the diets over 2 weeks before the indoor measurements. Feed was available for about 6 hours/day, as practiced commercially for wintering non-lactating cows.

RESULTS: Five cows fed the Straw diet had to be removed from the trial because of acute acidosis; four on Day 1 of the measurement period and one on Day 7. One cow allocated to the Silage diet refused to eat fodder beet bulbs and was also removed from the trial. Two cows fed the Silage diet were also treated for acidosis. DM intakes were lower with the Straw than Silage diets (6.4 (SE 0.4) vs. 8.3 (SE 0.5) kg/day) and organic matter (OM) digestibility was lower with the Straw than Silage diets (77 (SE 1) vs. 83 (SE 1) g/100g). The N content of the two diets was 1.14 and 1.75?g/100?g DM and there was a net loss of N by cows fed the Straw diet (?22.7 (SE 7) g/day). Rumen microbial N production was much lower in cows fed the Straw than the Silage diet (6.6 (SE 1.3) vs. 15.8 (SE 0.7) g microbial N/kg digestible OM intake). Concentrations of ammonia in rumen liquid collected on Days 5–6 were below detection limits (<0.1?mmol/L) in 36/48 (75%) samples collected from cows fed the Straw diet and in 27/48 (56%) cows fed the Silage diet. Mean urinary N excretion was lower in cows fed the Straw than the Silage diet (52.0 (SE 5.8) vs. 87.7 (SE 5.9) g/day).

CONCLUSION AND CLINICAL RELEVENCE: An over-wintering diet for dry cows comprising about 65% fodder beet with 35% pasture silage provided adequate nutrition, although there was some risk of acidosis. In contrast, the diet containing about 85% fodder beet with barley straw resulted in lower DM intakes, poor rumen function, negative N balance so that both nutrition and welfare were compromised.     

Effect of Nitrogen Rate and the Environment on Physicochemical Properties of Selected High‐Amylose Rice Cultivars

Genetic marker haplotypes for the Waxy and alk genes are associated with amylose content and gelatinization temperature, respectively, and are used by breeders to develop rice cultivars that have physicochemical properties desired by the parboiling and canning industries. Cultivars that provide consistent processing quality across diverse production environments are important to the industry. This study determined if measures of processing quality differed among cultivars, fertility treatments, and production environments. Nine cultivars having high amylose content (>23.0%) but with different Waxy and alk haplotypes were evaluated in three environments and using three nitrogen fertility levels. Although environment and fertility levels significantly (P < 0.05) impacted protein content, gelatinization temperatures, and peak, trough, and final paste viscosities, cultivars performed consistently across production environments and fertility applications. Differences were observed among cultivars in paste viscosity measures and gelatinization temperatures that corresponded with their Waxy and alk haplotypes. However, discriminant analysis revealed subgroupings within the same Waxy and alk haplotypes that were primarily differentiated by trough paste viscosity. The results of this study demonstrated that although these high‐amylose cultivars had consistent ranking across environments and nitrogen fertility regimes, there were differences in rice processing quality traits that were not apparent from their Waxy and alk haplotypes.     

Policies for the vaccination of cats and dogs in New Zealand veterinary practices

AIMS: To determine current practices and attitudes towards vaccination of dogs and cats of veterinarians in New Zealand; the methods used for informing clients on which vaccines to use, and the preferred site for vaccination of cats.

METHODS: A postal questionnaire was sent to all 483 listed veterinary practices in New Zealand during February 2012. Some questions were specific to pet dogs, cats, or working farm dogs. Responses were categorised according to practice type and geographical region of the respondent. Factors associated with respondent recommendation of annual vaccination with modified live viral (MLV) vaccines were examined using logistic regression analysis. Vaccines that were considered to be essential for every animal were defined as core; those that may be recommended for animals whose location or lifestyle placed them at risk, were defined as non-core.

RESULTS: There were 204 useable returns, equivalent to a response rate of 42.2%, distributed across the country. Annual vaccination with MLV vaccines of dogs was recommended by 54/198 (27.3%) respondents, and of cats by 107/181 (59.1%) respondents. Factors associated with the recommendation of annual administration of MLV vaccines to dogs included being a companion animal practice, a desire for policies on vaccination to be left to individual clinics, and having one veterinarian in the practice. Administration of the final vaccination for puppies was recommended at ≥14 weeks old by 55/185 (29.7%) respondents, and for kittens at ≥13 weeks old by 42/183 (23%) respondents. Of respondents that administered MLV vaccines annually, 62/103 (60.2%) believed reducing the frequency of vaccination would reduce income, and 52/103 (50.5%) considered it would have a negative effect on animal health. Advice to enable clients to decide which non-core vaccines were administered was given by 181/199 (91%) respondents. Factors considered when recommending a vaccine included consideration of risk to individual patients (190/203; 93.6%), requirements of boarding kennels/catteries (165/203; 81.3%) and clinic vaccination policy (142/203; 70%). The preferred site for administering MLV vaccines to cats was the dorsal neck or inter-scapular region (137/198; 69.2%). Amongst respondents, 18 wanted disease surveillance information to allow for truly informed decisions to be made about vaccination.

CONCLUSIONS AND CLINICAL RELEVANCE: Veterinarians can now compare their own vaccination practices and attitudes with those of veterinarians nationally, and internationally. There is a need for national surveillance information and for continued education of the public and commercial kennel and cattery owners for optimal vaccination strategies to be developed.     

Attitudes and perceptions of veterinary paraprofessionals in New Zealand to postoperative pain in dogs and cats

AIM: To survey the attitudes and perceptions of veterinary paraprofessionals in New Zealand to postoperative pain in dogs and cats.

METHODS: In December 2011, veterinary paraprofessionals (VP) from throughout New Zealand were invited to participate in an online survey. Eleven questions, which were divided into five sections, were used to determine demographic information, the respondents’ assessment of pain after commonly performed surgeries in dogs and cats, their opinions on provision of analgesia, who had responsibility for pain monitoring and the use of any formal pain scoring system in the practice.

RESULTS: Data from 165 respondents were able to be used, and 162 (98%) respondents to the survey were female. According to the respondents’ estimates, fracture repair in dogs and repair of diaphragmatic hernias in cats had the highest pain score following surgery. Neutering procedures involving dogs were scored higher than for cats (p<0.01). All respondents agreed that animals benefit from perioperative analgesia. The veterinary nurse was reported to be predominantly responsible for monitoring pain in animals postoperatively by 116/165 (70.3%) respondents. Of 165 respondents, 154 (93%) considered that their knowledge of pain and assessment of pain could be enhanced.

CONCLUSIONS: This survey reflects the attitudes and perceptions of a sample of VP in New Zealand to postoperative pain in dogs and cats. The results indicate that all respondents believe that surgery results in sufficient pain to warrant analgesic therapy. Routine neutering surgeries were considered to be more painful in dogs than in cats. The current survey also provides information to educators on potential areas of focus, given that 93% of respondents felt that their knowledge of pain and assessment of pain could be enhanced.     

Seroprevalence of Babesia bigemina in smallholder dairy cattle in Tanzania and associated risk factors

Variations in the seroprevalence of antibody to Babesia bigemina infection by farm and animal level risk factors were investigated for 2 contrasting regions of Tanga and Iringa in Tanzania. Tanga is situated in the eastern part of the country and has typical tropical coast climate while Iringa is situated in the Southern Highlands and has a tropical highland climate. Two hundred farms from each region were selected using simple random sampling procedure and visited once between January 1999 and April 1999. Blood samples were collected from 1329 smallholder dairy animals on selected farms for harvesting serum which was subsequently used for serodiagnosis of B. bigemina using an indirect enzyme linked immuno-sorbent assay (ELISA). Of the 1329 sera samples screened, 34.9 % were positive for B. bigemina. The prevalence was higher in Iringa Region [43%, 95% confidence intervals (CI) = 39.5-47.3] than in Tanga Region (27%, CI = 23.6-30.5). Using a logistic binomial regression model as an analytical method for predicting the likelihood of animal seropositivity, we found (in both regions) that the risk of positive reaction varied with the animal's age, history of grazing and geographical location. Seroprevalence increased with age (beta = 0.01 and 0.01 per year of age, P < 0.005 in Tanga and Iringa, respectively). Animals located in Lushoto and Iringa urban district were associated with increased risk of seropositivity [Odds ratio (OR) = 4.24, P = 0.001, for Lushoto, and OR = 1.81, P = 0.040, for Iringa Urban, respectively). Animals grazed 3 months prior to sampling had higher odds for seropositivity than zero/semi-grazed, despite farmer-reported high frequency of tick control (OR = 2.71, P = 0.0087, for Tanga, and OR = 4.53, P = 0.001, for Iringa). Our study suggests that even though herd sizes are small, B. bigemina infection is widespread in many smallholder dairy farms and endemic stability with respect to this disease has not yet been attained, but the observed levels are sufficiently high to ensure that clinical disease would be a risk.     

Impedimetric evaluation of compounds for antifungal activity versus Aspergillus niger

The procedure described utilized a microbial monitoring system (bactometer) to measure impedimetrically the inhibitory activity of known antifungal compounds (2-(thiocyanomethylthio)benzothiazole [TCMTB], 3-iodo-2-propynylbutyl carbamate [IPBC], chlorothalonil, tebuconazole, and copper-8-quinolinolate [Cu-8]) on growth of Aspergillus niger Teigh. in a liquid medium. The MIC values determined were based on the activity of the compounds to inhibit a change in the capacitance of the medium during a 96-h period after inoculation. The MIC values obtained with the bactometer were compared with MIC values derived from the inhibition of radial growth of A. niger on the same liquid medium solidified with agar. The MIC values for all the compounds tested were substantially lower when determined with the bactometer than on agar. The impedimetric evaluation of compounds for antifungal activity offers advantages of speed, sensitivity, and data collection.     

Effects of dietary level of ruminally protected choline on performance and carcass characteristics of finishing beef steers and on growth and serum metabolites in lambs

Ruminally protected choline (RPC) was evaluated in two experiments. In Exp. 1, beef steers (n = 160; average initial BW = 350.9 kg) were fed a 90% concentrate diet with either 0, .25, .5, or 1.0% RPC (DM basis) for 112 to 140 d. Feeding .25% RPC increased ADG 11.6% compared with 0% RPC, but responses diminished with increasing RPC level (cubic response, P < .10). Daily DMI was not affected by RPC level, but feed:gain was improved 6.8% with .25% RPC compared with 0% RPC, and responses diminished with increasing RPC level (cubic response, P < .10). Carcass yield grade increased linearly (P < .10) as RPC level increased, but marbling score was lower for all three RPC-containing diets than for the 0% RPC diet (quadratic response, P < .05). In Exp. 2, 20 Suffolk lambs (initial BW = 29.8 kg) were fed an 80% concentrate diet for 56 d with the same RPC levels as in Exp. 1. Serum triglycerides (TG) and cholesterol (CLSTRL) were measured in weekly blood samples, and intensive blood samples were collected on d 28 and 56 to evaluate serum insulin (INS), GH, and NEFA. For the 56-d feeding period, ADG responded quadratically (P < .10) to RPC level, but DMI and feed:gain were not affected. Serum INS and NEFA concentrations increased linearly (P < .05) and serum GH responded cubically (P < .05) to RPC level on d 28, but no differences were noted on d 56. Serum TG concentrations in weekly samples increased linearly (P < .10) with RPC level, but, averaged over all weeks, serum CLSTRL concentrations did not differ (P > .10) among treatments. Quantities of carcass mesenteric (P < .05) and kidney fat (P < .10) increased linearly, but longissimus muscle and liver fat contents did not differ (P > .10) among RPC levels. Supplementing RPC in high-concentrate diets improved performance, but results were not consistent among RPC levels or between cattle and sheep. Potential effects of RPC might be mediated through alterations in fat metabolism and(or) metabolic hormones related to fat metabolism.