Practical oxygen therapy for newborn piglets

Aims: To evaluate the effect of a novel method of practical oxygen therapy on physiological parameters related to survival, weaning weight and preweaning mortality of neonatal piglets under commercial farm conditions. Methods: Piglets from hyperprolific sows born with signs of asphyxia, (n = 109; <6 on a score of respiration, meconium staining and activity) or very low birth weight (VLBW; n = 112; <1.05 kg) were selected for the study. Approximately half of each group (n = 55 VLBW piglets and n = 57 piglets with asphyxia) received 100% oxygen immediately after birth using a specially designed facemask for 45 seconds (VLBW) or 1 minute (asphyxiated). Physiological parameters (peripheral blood oxygen saturation (SpO₂) blood glucose concentration and rectal temperature) were measured before oxygen treatment 5 minutes after birth (SpO₂) and 24 hours later (SpO₂, blood glucose concentration, temperature). Weight at birth, at 24 hours and at 21 days of age, preweaning mortality, and estimated colostrum intake were also recorded. Results: A significant treatment effect on SpO₂ was observed (p = 0.013 and p < 0.001 for VLBW and asphyxiated piglets respectively). VLBW and asphyxiated piglets that received oxygen treatment had higher SpO₂ after treatment (measured 5 minutes after birth, 97.7 and 97.8% respectively) compared to immediately after birth (93.3 and 86.8% respectively) while untreated piglets showed no variation. Blood glucose concentrations increased in all piglets between birth and 24 hours of age (p = 0.003 and p < 0.001 for asphyxiated and VLBW piglets respectively) and this was higher in asphyxiated piglets that received oxygen than those that did not (5.6 (SE 0.2) mmol/L; p < 0.05). Estimated colostrum intake was higher in asphyxiated (401.6 (SD 24.4) g/kg) and VLBW (374.9 (SE 23.4 g/kg) piglets that received oxygen than those that did not (273.2 (SE 24.1) g/kg; p < 0.001 and 249.0 (SE 22.5) g/kg; p < 0.001 respectively). Similarly weight at weaning was higher in asphyxiated (5.8 (SE 0.2) kg) and VLBW (4.9 (SE 0.2) kg) piglets that received oxygen therapy than control animals (4.9 (SE 0.2) kg; = 0.005 and 4.1 (SE 0.2) kg; p = 0.008 respectively). Furthermore, oxygen treatment markedly reduced preweaning mortality from 9/52 (17%) untreated to 1/57 (1.7%) oxygen-treated piglets suffering asphyxia at birth (p = 0.006). Conclusions: Oxygen therapy improves physiological and productive parameters in piglets born with signs of asphyxia or VLBW. The incorporation of this strategy as part of the farrowing routine enhances the advantages of rearing hyperprolific sows.

Determination of Clopidol Residues in Chicken Tissues by Liquid Chromatography: Collaborative Study

Eighteen laboratories participated in a collaborative study on the determination of clopidol residues in chicken muscle tissues by liquid chromatography. Of these, results from 16 laboratories which rigorously followed the method were subjected to statistical analysis. The method performance was assessed by all participants using 14 samples of chicken muscle fortified at concentrations ranging from 0.1 to 5.0 mg/kg. In addition, 9 participants each reported results for 6 clopidol-incurred samples in chicken muscle. Test portions were extracted with acetonitrile, and the extracts were purified with alumina and anion exchange resin solid-phase extraction cartridges in sequence. Clopidol was separated by reversed-phase liquid chromatography and quantified at 270 nm. Average recoveries ranged from 81.8 to 85.4%, reproducibility relative standard deviation (RSDR) ranged from 11.9 to 22.6%, and repeatability relative standard deviation (RSDr) ranged from 9.9 to 15.1%. For clopidol-incurred samples at concentrations of 0.100–0.687 mg/kg, the mean determination value range was 0.099–0.659 mg/kg; RSDR was 12.6–19.8%, RSDr was 3.1–8.5%; and HORRAT values were 0.7–1.1. The accuracy and precision of the method are in conformity with the requirements specified by AOAC INTERNATIONAL. The method was adopted Official First Action in April 2003.

Fosfomycin residues in colostrum: Impact on morpho-physiology and microbiology of suckling piglets

Fosfomycin is a broad-spectrum bactericidal antibiotic widely used in pig farms for the treatment of a wide variety of bacterial infections. In this study, the elimination of disodium fosfomycin in colostrum/milk of the sow and the impact of this antibiotic on the microbiota and intestinal morpho-physiology of suckling piglets were analyzed. The average amount of fosfomycin eliminated in colostrum (after administration of 15 mg/kg IM) during the first 10 hr postpartum was 0.85 μg/ml, and the mean residual amount ingested by the piglets was 0.26 mg/kg. The elimination profile of fosfomycin concentrations in colostrum occurs at a time of profound changes in the morpho-physiology of the gastrointestinal tract of the piglet. However, the studied concentrations did not produce imbalances on the microbiota or on the morpho-physiology of the gastrointestinal tract of the piglet. Concentrations of fosfomycin were maintained in the mammary gland above the MIC for more than 8 hr for pathogenic bacteria of productive importance. This would indicate that fosfomycin may be considered safe for the specific treatment of bacterial infectious processes in sows during the peri- and postpartum period. This first study with disodium fosfomycin stimulates awareness in the proper use of antimicrobials at farrowing.

Disodium-fosfomycin pharmacokinetics and bioavailability in post weaning piglets

Disodium-fosfomycin pharmacokinetics has been studied in different species after oral, intravenous, intramuscular and subcutaneous administration. At present there are neither documented clinical experiences of the use of fosfomycin in pigs nor any published studies in weaning piglets, although it is a period of high incidence of infectious diseases. The pharmacokinetics and the bioavailability of sodium fosfomycin were studied in post weaning piglets after intravenous and intramuscular administration of 15 mg/kg of body weight. Plasma concentrations were measured by a high-performance liquid ms/ms. After IV administration the area under the fosfomycin concentration:time curve in plasma was AUC(0-12) of 120.00 ± 23.12 μg h/ml and the volume of distribution (Vd) of 273.00 ± 40.70 ml/kg. The elimination was rapid with a plasma clearance of 131.50 ± 30.07 ml/kg/h and a T(1/2) of 1.54 ± 0.40 h. Peak serum concentration (Cmax), Tmax, AUC(0-12) and bioavailability for the IM administration were 43.00 ± 4.10 μg/ml, 0.75 ± 0.00 h, 99.00 ± 0.70 μg h/ml and 85.5 ± 9.90% respectively. Different authors have determined a minimum inhibitory concentration (MIC90) ranging from 0.25 μg/ml for Streptococcus sp. and 0.5 μg/ml for Escherichia coli. Considering the above, and according to the values of plasma concentration vs time profiles observed in this study, effective plasma concentrations of fosfomycin for sensitive bacteria can be obtained following IV and IM administration of 15 mg/kg in piglets.

11 EVALUATION OF A CONTINUING EDUCATION PROGRAM FOR VETERINARIANS: OUTCOME ASSESSMENT OF APPLIED REPRODUCTIVE TECHNIQUES IN BEEF PRODUCTION

Continuing education programs are an important tool to improve the service quality of veterinarians (Moore et al. 1996 JAVMA 209, 1086; Moore et al. 2004 JVME 31, 146). The effectiveness of a continuing education program (CEP) designed to enhance the flow of applied, scientific-based, reproductive techniques (in addition to nutrition, economy, and animal health) from educators (n = 21) to beef veterinarians (n = 400) was evaluated during a period of four years (2003 through 2007) in Argentina. Control of the estrous cycle, artificial insemination, pregnancy diagnosis, development of replacement heifers, record keeping systems, breeding soundness examination, and reproductive health practices were included in the analysis. The CEP included lectures and hands-on practice activities (100 h year–1). Participants were evaluated prior to the enrollment (CON) in the CEP to determine reproductive weakness areas. The outcome assessment from educators to veterinarians (contents of the program and benefits for participants) of applied reproductive techniques was evaluated through a test of knowledge and a survey following the IACET guideline at the end of each academic year (TRT). Data were analyzed using the MIXED procedure of SAS (SAS Institute, Inc., Cary, NC, USA) in a cohort study. Prior to the enrollment, control of the estrous cycle, semen evaluation, and record keeping systems were found to be the major areas of weakness in CON participants. Participants agreed with the information provided in the program and they indicated that the contents learned were relevant (97 � 3%) and applicable (92 � 4%). Furthermore, the CEP met their expectations (97 � 3%) and improved the quality of the service (94 � 3%) of TRT participants. Development of replacement heifers, control of the estrous cycle, semen evaluation, record keeping systems, and reproductive health problems were indicated as the most important tools (>80%; P < 0.05) to improve beef production. Additionally, results of this evaluation did reveal new areas for improvement such as open communication channels between educators and practitioners, data management, and communication skills of participants, all of which may be necessary to increase the acceptance and impact of applied reproductive techniques by beef producers. In conclusion, effective professional CEP improved the quality service of participating veterinarians, adding new services and implementing new management strategies. For the CEP to truly be considered successful, the program must also reach the ultimate end user, the beef producers. Therefore, a detailed assessment of the real acceptance and impact of these applied reproductive techniques by beef producers is needed to improve our message delivery from educators to practitioners and beef producers.

Pharmacokinetics and synovial fluid concentrations of flurbiprofen enantiomers in horses: chiral inversion

Flurbirpofen (FBP), a member of the 2-aryl propionate nonsteroidal anti-inflammatory drug class, has potent anti-inflammatory and analgesic properties. The commercial preparation is a racemic mixture of the R(-) and S(+) enantiomers of FBP. In this study, R(-) and S(+) FBP were used to investigate the metabolic chiral inversion. Each enantiomer was administered separately (0.25 mg/kg) and in a racemic mixture (0.5 mg/kg) intravenously to horses. Plasma and synovial concentration of each enantiomer was determined and the disposition of each was analyzed. After intravenous administration of R(-) FBP and S(+) FBP to horses no chiral inversion was detected. After the administration of the FBP racemate and individual enantiomers no differences were observed between pharmacokinetic parameters [t(1/2beta) (h), Cl (L/h.kg), AUC (microg.h/mL), Vss (L/kg) and MRT (h)] for R(-) and S(+) FBF. Synovial fluid concentrations of both FBP enantiomers were lower than plasma concentrations and no stereoselective differences were detected. These data indicate that the disposition of FBF in horses is not enantioselective and demonstrate a difference in the pharmacokinetic behavior of the enantiomers as compared with other 2-aryl-propionic acids, such as carprofen, ketoprofen and vedaprofen in the horse.

Disposition of suprofen enantiomers in the cat

Suprofen (SPF) is a non-steroidal anti-inflammatory drug (NSAID), which belongs to the 2-arylpropionic acids subclass. As a result of their chiral characteristics, these compounds have shown a marked enantioselective behaviour with a high degree of interspecies variation. They are mainly eliminated by glucuronidation. Plasma, biliary and urine disposition of SPF was investigated in the cat after intravenous administration of the racemate (dose 2 mg/kg). Both enantiomers exhibited similar disposition profiles in plasma with no evidence of chiral inversion. During bile sampling time, recovered acylglucuronides of R (-) and S (+) SPF were less than 1% of the total dose administered. Only free SPF was recovered in the urine, representing 0.12% of the administered racemic SPF dose. The results indicate that neither chiral inversion nor glucuronidation predominate in SPF disposition in cats.

Enantioselective behaviour of drugs used in domestic animals: a review

The chirality of drugs, with particular reference to agents used in veterinary medicine, is reviewed. Basic concepts of chirality and aspects of the methodology for the separation of enantiomers are considered. Chiral compounds are in common use in animals and their pharmacological actions and side-effects (pharmacodynamics) and absorption into and fate within the body (pharmacokinetics) are of fundamental importance; pharmacodynamic and pharmacokinetic properties of enantiomeric pairs commonly differ and this has major implications for their effective and safe therapeutic use. As examples of the particular significance of chirality in veterinary medicine, the following drug classes are reviewed; benzimidazole anthelmintics, cloprostenol, verapamil, ketamine, halogenated hydrocarbon anaesthetics and 2-arylpropionic acid anti-inflammatory drugs. The implications of chirality for drug product development and approval by registration authorities are discussed.

Pharmacokinetics of cefoperazone in horses

The pharmacokinetics and bioavailability of cefoperazone (CPZ) were studied following intravenous (IV) and intramuscular (IM) administration of single doses (30 mg/kg) to horses. Concentrations in serum, urine and synovial fluid samples were measured following IV administration. CPZ concentrations in serum, synovial fluid and spongy bone samples were measured following IM administration. After IV administration a rapid distribution phase (t1/2 (alpha): 4.22 +/- 2.73 min) was followed by a slower elimination phase (t1/2(beta) 0.77 +/- 0.19 h). The apparent volume of distribution was 0.68 +/- 0.10 L/kg. Mean synovial fluid peak concentration was 5.76 +/- 0.74 microgram/mliter. After IM administration a bioavailability of 42.00 +/- 5.33% was obtained. Half-life of absorption was 2.51 +/- 0.72 min and t1/2(beta) was 1.52 +/- 0.15 h. The mean synovial fluid and spongy bone peak concentrations at 2 h after IM administration were 2.91 +/- 0.85 microgram/mliter and 5.56 +/- 0.70 microgram/mliter, respectively.

Pharmacokinetics of ticarcillin and ticarcillin-probenecid in sheep

Serum concentrations of ticarcillin were measured serially over a period of 12h in a cross over trial involving 6 healthy adult ewes after intravenous and intramuscular (IM) administration of 40 mg ticarcillin per kg body weight. Probenecid (40 mg/kg) was also administered IM immediately before the IM administration of 40 mg/kg ticarcillin. Pharmacokinetic values after intravenous administration were: half-life of elimination (T 1/2 beta) = 0.90 +/- 0.09 h; volume of distribution at steady state (Vdss) = 456.8 +/- 106.6 ml/kg, total body clearance (CIB) = 614.5 +/- 81.2 ml/h/kg. Ticarcillin persisted in serum at greater than or equal to 1.5 micrograms/ml for 4 hours. Pharmacokinetic and bioavailability values after intramuscular administration were: half-life of absorption (T 1/2 ab) = 8.08 +/- 1.98 min; T 1/2 beta = 0.96 +/- 0.07 h. Peak serum concentration (Cmax) was 31.11 +/- 6.02 micrograms/ml at 0.50 h (Tmax), bioavailability (F) was 0.82 +/- 0.09. After ticarcillin was administered IM together with probenecid the T 1/2 ab was 33.9 +/- 13.7 min, the T 1/2 beta 2.66 +/- 0.65 h, Cmax = 44.87 +/- 5.58 at 1.33 +/- 0.44 h, and F = 1.25 +/- 0.23.