CHEMOTHERAPY OF ACUTE BOVINE ANAPLASMOSIS

The efficacy of a standard tetracycline, imidocarb and a new experimental long-acting tetracycline (T-200) in the treatment of anaplasmosis was examined in 5 groups of 9 nonsplenectomised, adult, 4-year-old, speyed cattle. The efficacy of T-200 was further examined using 9 splenectomised calves. One treatment of imidocarb (3.5 mg/kg) or T-200 (20 mg/kg) or 2 treatments (10 mg/kg) of a standard tetracycline were very effective in controlling the infection in the intact cattle. On inoculation of T-200 (20 mg/kg) controlled infection in 5 splenectomized calves, whereas all 4 untreated control calves died. T-200 did not sterilise either intact or splenectomised cattle.     

In-vivo therapeutic efficacy trial with artemisinin derivative, buparvaquone and imidocarb dipropionate against Babesia equi infection in donkeys

The therapeutic efficacy of imidocarb, artesunate, arteether, buparvaquone and arteether+buparvaquone combination was evaluated against Babesia equi of Indian origin in splenectomised donkeys with experimentally induced acute infection. Efficacies of these drugs were tested by administering each drug or drug combination to groups of donkeys (having three donkeys each group). One group of donkey was kept as untreated control for comparing the results. Parasitaemia, haematology (WBC, RBC, PCV, granulocytes and haemoglobin), biochemical parameters (SAST, SALT, alkaline phosphatase, albumin/globulin ratio) were monitored at regular intervals. Individually, arteether and buparvaquone were found to have no parasite clearing efficacy and the treated animals died within 5-6 days after showing high parasitaemia and clinical symptoms of the disease. However, artesunate treated animals were able to restrict the parasite multiplication but only during the treatment period. Animals treated with imidocarb and arteether+buparvaquone combination were able to clear the parasite from the blood circulation after 2-5 days post-treatment (PT). After 55-58 days PT, recrudescence of B. equi parasite was observed in both these groups and a mean survival period of 66 days and 69 days, respectively, was recorded in these groups. Results of haemato-biochemical parameters had shown that imidocarb had deleterious effect on the liver function while on the other hand arteether+buparvaquone combination was found to be safe. This limited study indicates that arteether+buparvaquone combination could be a better choice than imidocarb for treating B. equi infection, but further trials are required in detail.     

Pharmacokinetics of imidocarb dipropionate in horses after intramuscular administration

The objective of this study was to determine the pharmacokinetic behaviour of imidocarb in horses following a single i.m. injection at the dose commonly administered to treat Babesia caballi infections or to prevent babesiosis. Eight horses were injected i.m. with a single dose of 2.4 mg imidocarb dipropionate/kg bwt and blood, faecal, urine and milk samples were collected. For imidocarb determination, a high-performance liquid chromatographic method (HPLC) was used after weak cation-exchange solid phase, or liquid-liquid, extraction procedures. Twelve hours after treatment, no detectable plasma concentrations were recorded in any of the treated animals. The distribution and elimination patterns of the drug suggested that it is quickly sequestrated in some storage tissues and remains in the body for a long time. Its prolonged presence in the body may confer a reservoir effect to imidocarb in some tissues, therefore making it undetectable in the plasma of animals but sufficient to produce its described therapeutic and prophylactic activities.     

Pharmacokinetics of sulfamethoxazole and trimethoprim in donkeys, mules, and horses

OBJECTIVE: To compare serum disposition of sulfamethoxazole and trimethoprim after IV administration to donkeys, mules, and horses. ANIMALS: 5 donkeys, 5 mules, and 3 horses. PROCEDURE: Blood samples were collected before (time 0) and 5, 15, 30, and 45 minutes and 1, 1.25, 1.5, 1.75, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 8, 10, and 24 hours after IV administration of sulfamethoxazole (12.5 mg/kg) and trimethoprim (2.5 mg/kg). Serum was analyzed in triplicate with high-performance liquid chromatography for determination of sulfamethoxazole and trimethoprim concentrations. Serum concentration-time curve for each animal was analyzed separately to estimate noncompartmental pharmacokinetic variables. RESULTS: Clearance of trimethoprim and sulfamethoxazole in donkeys was significantly faster than in mules or horses. In donkeys, mean residence time (MRT) of sulfamethoxazole (2.5 hours) was less than half the MRT in mules (6.2 hours); MRT of trimethoprim in donkeys (0.8 hours) was half that in horses (1.5 hours). Volume of distribution at steady state (Vdss) for sulfamethoxazole did not differ, but Vdss of trimethoprim was significantly greater in horses than mules or donkeys. Area under the curve for sulfamethoxazole and trimethoprim was higher in mules than in horses or donkeys. CONCLUSIONS AND CLINICAL RELEVANCE: Dosing intervals for IV administration of trimethoprim-sulfamethoxazole in horses may not be appropriate for use in donkeys or mules. Donkeys eliminate the drugs rapidly, compared with horses. Ratios of trimethoprim and sulfamethoxazole optimum for antibacterial activity are maintained for only a short duration in horses, donkeys, and mules.     

Evaluation of the sedative and clinical effects of xylazine,detomidine, medetomidine and dexmedetomidine in miniature donkeys

ABSTRACT

Aim: To evaluate the sedative and clinical effects of I/V xylazine, detomidine, medetomidine and dexmedetomidine in miniature donkeys.

Methods: Seven clinically healthy, male adult miniature donkeys with a mean age of 6 years and weight of 105?kg, were assigned to five I/V treatments in a randomised, cross-over design. They received either 1.1?mg/kg xylazine, 20?μg/kg detomidine, 10?μg/kg medetomidine, 5?μg/kg dexmedetomidine or saline, with a washout period of ≥7 days. The degree of sedation was scored using a 4-point scale by three observers, and heart rate (HR), respiration rate (RR), rectal temperature and capillary refill time (CRT) were recorded immediately before and 5, 10, 15, 30, 60, 90 and 120 minutes after drug administration.

Results: All saline-treated donkeys showed no sedation at any time, whereas the donkeys treated with xylazine, detomidine, medetomidine and dexmedetomidine had mild or moderate sedation between 5 and 60 minutes after treatment, and no sedation after 90 minutes. All animals recovered from sedation without complication within 2 hours. The mean HR and RR of saline-treated donkeys did not change between 0 and 120 minutes after administration, but the mean HR and RR of donkeys treated with xylazine, detomidine, medetomidine and dexmedetomidine declined between 5 and 60 minutes after drug administration. The mean rectal temperature of all treated donkeys did not change between 0 and 120 minutes after administration. The CRT for all donkeys was ≤2 seconds at all times following each treatment.

Conclusions and clinical relevance: Administration of xylazine at 1.1?mg/kg, detomidine at 20?μg/kg, medetomidine at 10?μg/kg and dexmedetomidine at 5?μg/kg resulted in similar sedation in miniature donkeys. Therefore any of the studied drugs could be used for sedation in healthy miniature donkeys.     

Pharmacokinetics and bioavailability of imidocarb dipropionate in swine

A two-way crossover study was performed in eight healthy young pigs to determine the pharmacokinetics of imidocarb dipropionate (IMDP) following intravenous (2 mg/kg b.w.) and intramuscular (2 mg/kg b.w.) administrations. Each animal received one intravenous and one intramuscular injection with a 30-day washout period between the two-treatments. Plasma concentrations were measured by high-performance liquid chromatography (HPLC) assay with UV detector at regular intervals for up to 24 h post-injection. Intravenous plasma concentration profiles best fit a three-compartmental model yielding a mean system clearance (Cl((s))) of 558 mL/kg.h and a mean half-life of 13.91 h. Mean imidocarb AUC((0-infinity)) (microg.h/mL), V(c) (L/kg), V(d(area))(L/kg) and MRT((0-t)) (h) values were 3.58, 0.11, 14.36 and 1.46, respectively. Compartmental modeling of imidocarb, after intramuscular administration produced best fit for two-compartmental model yielding mean Kalpha (h(-1)), Cmax (microg/mL), tmax (h), and bioavailability (%) of 3.89, 2.02, 0.54, and 86.57 for the 2 mg/kg dose level. The present studies showed that IMDP was rapidly absorbed, widely distributed, and slowly eliminated. No adverse effects were observed in any of the pigs after i.v. and i.m. administrations of IMDP. The favorable PK behavior, such as the long half-life, acceptable bioavailability indicated that it is likely to be effective in pigs.     

Pharmacokinetics of flunixin meglumine in donkeys, mules, and horses

OBJECTIVE: To compare serum disposition of flunixin meglumine after i.v. administration of a bolus to horses, donkeys, and mules. ANIMALS: 3 clinically normal horses, 5 clinically normal donkeys, and 5 clinically normal mules. PROCEDURE: Blood samples were collected at time zero (before) and 5, 10, 15, 30, and 45 minutes, and at 1, 1.25, 1.5, 1.75, 2, 2.5, 2.75, 3, 3.5, 4, 4.5, 5, 5.5, 6, and 8 hours after i.v. administration of a bolus of flunixin meglumine (1.1 mg/kg of body weight). Serum was analyzed in duplicate by the use of high-performance liquid chromatography for determination of flunixin meglumine concentrations. The serum concentration-time curve for each horse, donkey, and mule were analyzed separately to estimate noncompartmental pharmacokinetic variables RESULTS: Mean (+/-SD) area under the curve for donkeys (646 +/- 148 minute x microg/ml) was significantly less than for horses (976 +/- 168 minute x microg/ml) or for mules (860 +/- 343 minute x microg/ml). Mean residence time for donkeys (54.6 +/- 7 minutes) was significantly less than for horses (110 +/- 24 minutes) or for mules (93 +/- 30 minutes). Mean total body clearance for donkeys (1.78 +/- 0.5 ml/kg/h) was significantly different from that for horses (1.14 +/- 0.18 ml/kg/h) but not from that for mules (1.4 +/- 0.5 ml/kg/h). Significant differences were not found between horses and mules for any pharmacokinetic variable. CONCLUSION AND CLINICAL RELEVANCE: Significant differences exist with regard to serum disposition of flunixin meglumine in donkeys, compared with that for horses and mules. Consequently, flunixin meglumine dosing regimens used in horses may be inappropriate for use in donkeys.     

Absorption, distribution, and excretion of imidocarb dipropionate in sheep

Spectrophotometric and thin-layer chromatographic methods for determination of imidocarb in biological specimens are described. Following intravenous injection of imidocarb (2.0 mg/kg) into 3 sheep, plasma concentrations, initially averaging 10.8 microgram/ml, decreased to an average of 1.9 microgram/ml within 1 hour and then to less than 1 microgram/ml within the next 4 hours. When imidocarb (4.5 mg/kg) was injected intramuscularly (IM) into 7 sheep, peak plasma concentrations averaging 7.9 microgram/ml were achieved within 4 hours and then rapidly decreased to 4.6 microgram/ml within the next 2 hours. Plasma values then decayed very slowly by first-order kinetics and trace amounts were still present 4 weeks after treatment. Imidocarb was bound to plasma proteins and the apparent volume of distribution was estimated to be slightly higher than the total body water. The concentrations of the drug in the plasma and in the erythrocytes were approximately equal. Detectable amounts were present in all examined tissues 4 weeks after IM administration Twenty-four hours after IM administration, the highest concentrations were in kidney, liver, and brain. The 14C-labeled imidocarb could be detected in all regions of the central nervous system examined, in the hypophysis, and in the pineal body. Metabolic or biotransformation products were not detected by the methods used. Of the administered IM dose, 11 to 17% was excreted in the urine within 24 hours; thereafter, the excretion rate was low, and detectable amounts were still present in the urine for 4 weeks. Renal clearance of imidocarb was less than glomerular filtration rate, indicating net tubular reabsorption. The relatively high concentration of imidocarb in the bile suggests that the bile is an important route of excretion. High concentrations were also found in the mild of lactating ewes, but the drug could not be detected in the plasma of lambs fed milk from these ewes.     

Clinicopathological changes and effect of imidocarb therapy in dogs experimentally infected with Babesia canis

In this study one spleen-intact dog (A) and two splenectomised dogs (BSE, CSE) were infected with Babesia canis. All animals developed an acute disease characterised by fever, haemoglobinuria and anaemia, the latter being more severe in the splenectomised dogs. Fever and parasitised red blood cells were detected for three days after imidocarb treatment in the splenectomised animals. Haematological abnormalities included regenerative anaemia, thrombocytopenia and leukopenia (due to neutropenia and lymphopenia) in the acute phase, soon followed by leukocytosis, neutrophilia and left shift a few days later. Acute hepatopathy was detected in all dogs with elevated ALT activity, which was more seriously altered in the splenectomised dogs. Diffuse changes in liver structure and hepatomegaly were seen by ultrasonography. Liver biopsy and histology revealed acute, non-purulent hepatitis in the splenectomised dogs. Both splenectomised dogs were successfully cured after collection of 400 ml highly parasitised blood, proving that large-amount antigen production is possible with rescuing the experimental animals. Whole blood transfusion, imidocarb and supportive care with infusions, antipyretics, glucocorticoids and diuretics were applied. The spleen-intact dog clinically recovered after receiving supportive treatment, with no imidocarb therapy. Microbial infections developed in both splenectomised animals (BSE: haemobartonellosis, CSE: osteomyelitis caused by Escherichia coli), probably as a consequence of immunosuppression after splenectomy and glucocorticoid therapy.     

Comparative pharmacokinetics of meloxicam in clinically normal horses and donkeys

OBJECTIVE: To determine the disposition of a bolus of meloxicam (administered IV) in horses and donkeys (Equus asinus) and compare the relative pharmacokinetic variables between the species. ANIMALS: 5 clinically normal horses and 5 clinically normal donkeys. PROCEDURES: Blood samples were collected before and after IV administration of a bolus of meloxicam (0.6 mg/kg). Serum meloxicam concentrations were determined in triplicate via high-performance liquid chromatography. The serum concentration-time curve for each horse and donkey was analyzed separately to estimate standard noncompartmental pharmacokinetic variables. RESULTS: In horses and donkeys, mean +/- SD area under the curve was 18.8 +/- 7.31 microg/mL/h and 4.6 +/- 2.55 microg/mL/h, respectively; mean residence time (MRT) was 9.6 +/- 9.24 hours and 0.6 +/- 0.36 hours, respectively. Total body clearance (CL(T)) was 34.7 +/- 9.21 mL/kg/h in horses and 187.9 +/- 147.26 mL/kg/h in donkeys. Volume of distribution at steady state (VD(SS)) was 270 +/- 160.5 mL/kg in horses and 93.2 +/- 33.74 mL/kg in donkeys. All values, except VD(SS), were significantly different between donkeys and horses. CONCLUSIONS AND CLINICAL RELEVANCE: The small VD(SS) of meloxicam in horses and donkeys (attributed to high protein binding) was similar to values determined for other nonsteroidal anti-inflammatory drugs. Compared with other species, horses had a much shorter MRT and greater CL(T) for meloxicam, indicating a rapid elimination of the drug from plasma; the even shorter MRT and greater CL(T) of meloxicam in donkeys, compared with horses, may make the use of the drug in this species impractical.     

Pharmacokinetics of phenylbutazone and its metabolite oxyphenbutazone in miniature donkeys

OBJECTIVE: To describe the pharmacokinetics of phenylbutazone and oxyphenbutazone after IV administration in miniature donkeys. ANIMALS: 6 clinically normal miniature donkeys. PROCEDURE: Blood samples were collected before and 5, 10, 20, 30, 45, 60, 90, 120, 180, 240, 300, 360, and 480 minutes after IV administration of phenylbutazone (4.4 mg/kg of body weight). Serum was analyzed in triplicate by use of high-performance liquid chromatography for determination of phenylbutazone and oxyphenbutazone concentrations. The serum concentration-time curve for each donkey was analyzed separately to estimate model-independent pharmacokinetic variables. RESULTS: Serum concentrations decreased rapidly after IV administration of phenylbutazone, and they reached undetectable concentrations within 4 hours. Values for mean residence time ranged from 0.5 to 3.0 hours (median, 1.1 hour), whereas total body clearance ranged from 4.2 to 7.5 ml/kg/min (mean, 5.8 ml/kg/min). Oxyphenbutazone appeared rapidly in the serum; time to peak concentration ranged from 13 to 41 minutes (mean, 26.4 minutes), and peak concentration in serum ranged from 2.8 to 4.0 mg/ml (mean, 3.5 microg/ml). CONCLUSION AND CLINICAL RELEVANCE: Clearance of phenylbutazone in miniature donkeys after injection of a single dose (4.4 mg/kg, IV) is rapid. Compared with horses, miniature donkeys may require more frequent administration of phenylbutazone to achieve therapeutic efficacy.     

Depletion of gentamicin in the milk of Holstein cows after single and repeated intramammary and parenteral treatments

Twenty-four healthy Holstein cows, 2.72 ± 0.64 (mean ± SD) years old, weighing 603.96 ± 73.22 kg (mean ± SD), and representing various levels of milk production, were used to determine the depletion of gentamicin (GT) in milk. The cows had not received antibiotics or other drugs that could interfere with study for at least 60 days before the beginning of the investigation. The cows were divided into six groups (n = 4) and treated with single (treatments A, B and C) or repeated (treatments D, E and F) doses of GT. Cows were acclimated for 7 days before administration of GT and milked twice a day at 12-h intervals (06.00 hours, 18.00 hours) throughout the duration of the study. Control milk samples were obtained after the arrival of the cows and assayed to establish their GT free status. On day 1 of each treatment, a baseline milk sample was collected from the milk produced (06.00 hours) by each cow. A single dose of GT was administered intramammarlly (A, i.m.m. left front quarter, 500 mg), intravenously (B, i.v., 5 mg/kg body weight) or intramuscularly (C, i.m., 5 mg/kg body weight). Cows in treatments D (i.m.m., 500 mg), E (i.v., 5 mg/kg body weight) and F (simultaneous i.m.m. 500 mg plus i.v. 5 mg/kg body weight) were treated twice a day for 5 consecutive days just after the morning and evening milkings. Milk samples from individual cows were collected every day after each milking during and after dosing until GT concentration in the milk was below the safe level of ± 30 ng/mL. The concentration of GT in milk was determined by a high-performance liquid chromatographic procedure. Depletion of GT to a concentration ± 30 ng/mL occurred at the seventh (84 h), third (36 h), third (36 h), eleventh (132 h), third (36 h) and nineteenth (228 h) post-dosing milking, for cows in treatments A, B, C., D, E and F respectively. The highest mean ± SEM) concentrations of GT were 14 710 ± 1213.89, 167.87 ± 46.94 and 91.62 ± 14.55 ng/mL measured in the first milking post dosing (12 h) for cows in treatment A, B and C respectively; for cows in treatments D, E and F, during the dosing period, they were 14067.50 ± 2989.09, 446.07 ± 100.92, and 22900 ± 2843.66 ng/mL and occurred at the seventh, third and eighth milking respectively. Because GT is not approved for use in dairy cattle and because of the long depletion time associated with some possible treatments, illegal and extra-label use is likely to cause residues in milk.     

Drug-resistant Trypanosoma congolense in naturally infected donkeys in north Omo Zone, southern Ethiopia

A three-part study was conducted to determine the efficacy of isometamidium chloride in donkey populations naturally infected with trypanosomes in north Omo Zone, southern Ethiopia. In the first, 373 randomly selected donkeys from four villages were examined for trypanosome infections by the dark ground/phase contrast buffy coat technique (BCT) in November 1999. The trypanosome prevalence was 18.2% (95% confidence interval (CI): 14.4, 22.5) and Trypanosoma congolense was the most common species accounting for 66.2% of the overall infections. In the second part, 40 infected donkeys were selected and treated with a prophylactic dose of 1.0mg/kg of isometamidium chloride and thereafter monitored every 14 days for 90 days. Trypanosomes were detected in eight donkeys within 1 month and in 20 donkeys within 2 months of treatment. About 16% (5/32) of donkeys infected with T. congolense were detected parasitemic 1 month after treatment. In addition, the result also revealed that all relapse/breakthrough infections were due to T. congolense. In the third part of this study mice were infected with two T. congolense field isolates from donkeys that were found to be parasitemic within 1 or 2 months after isometamidium treatment. The mice were treated with ranges of doses of isometamidium chloride or diminazene aceturate and thereafter followed for relapse infection. Isometamidium chloride at doses 0.5-4 mg/kg body weight and diminazene aceturate at doses of 3.5-28 mg/kg body weight failed completely to cure T. congolense infections in any of the mice.     

Pharmacokinetics of flumequine in sheep after intravenous and intramuscular administration: bioavailability and tissue residue studies

The pharmacokinetic properties of flumequine and its metabolite 7-hydroxyflumequine were determined in six healthy sheep after single intramuscular (i.m.) and intravenous (i.v) injections at a dose of 6 mg/kg body weight. The tissue residues were determined in 20 healthy sheep after repeated i.m. administration with a first dose of 12 mg/kg and nine doses of 6 mg/kg. The flumequine formulation used was Flumiquil 3% Suspension Injectable®. The mean plasma concentrations of flumequine after i.v. administration were described by a three-compartment open model with a rapid distribution and a relatively slow elimination phase. The low value of volume of distribution at steady state (V_dss) (0.52 ± 0.24 L/kg) and high value of volume of distribution (V_dλ₃) (5.05 ± 3.47 L/kg) emphasized the existence of a small compartment with a slow rate of return to the central compartment. The mean elimination half-life was 11.5 h. The 7-hydroxyflumequine plasma levels represented 2.3% of the total area under the curve. The mean plasma concentrations of flumequine after i.m. administration were characteristic of a two-compartment model with a first order absorption. The mean maximal plasma concentration (1.83 ± 1.15 μg/mL) was obtained rapidly, i.e. 1.39 ± 0.71 h after the i.m. administration. The fraction of dose absorbed from the injection site was 85.00 ± 30.13%. The minimal concentrations of flumequine during repeated treatment were significantly lower in females than in males. Eighteen hours after the last repeated i.m. admini-stration, the highest concentration of flumequine was observed at the injection sites followed by kidney, liver, muscle and fat. The highest concentration of 7-hydroxyflumequine was observed in the kidney and was ten times lower than the flumequine concentration. The longest flumequine elimination half-life was observed in the fat.     

Rectal temperature responses of donkeys administered with ascorbic acid and subjected to load carrying (packing) during the harmattan season in Nigeria

The aim of the experiment was to evaluate the effect of 4-h load carrying (packing) on donkeys administered with ascorbic acid (AA) during the harmattan season. Six donkeys administered orally with ascorbic acid (200 mg/kg) and subjected to packing served as experimental animals, while six others given only distilled water served as control animals. The rectal temperature (RT) of each donkey and dry-bulb temperature (DBT) and relative humidity (RH) of the research pen were recorded at 0600 hours pre-packing; while post-packing, the values were obtained at 1430, 1600 and 1800 hours. The DBT values (ranges) recorded before, during and after packing were 13.7?±?1.3 °C (11–15 °C), 28.4?±?1.0 °C (22.7–30.3 °C) and 30.6?±?3.0 °C (19.8–45 °C), respectively. The highest temperature–humidity index (THI) of 83.4?±?6.9 was obtained at 1430 hours after packing, and the value decreased to 64.2?±?5.8 at 1800 hours. The thermal environmental conditions were outside the thermoneutral zone for the donkeys. The RT values recorded immediately after packing did not differ (P?>?0.05) in experimental and control donkeys; but at 1600 and 1800 hours, values obtained in control donkeys (38.48?±?0.12 and 38.12?±?0.12 °C, respectively) were significantly higher (P?<?0.05) than those recorded in experimental donkeys (38.16?±?0.14 and 37.85?±?0.14 °C, respectively). In conclusion, administration of ascorbic acid reduced the rise in RT due to packing and may be of value in the amelioration of adverse effects of heat stress associated with work in donkeys.     

Imidocarb and parvaquone in the treatment of piroplasmosis (Babesia equi) in equids

The therapeutic efficacies of imidocarb and parvaquone were tested against Babesia equi of European origin in carrier horses and for induced acute infections in splenectomized ponies. Imidocarb, at a dosage of 4 mg/kg of body weight, given IM at 72-hour intervals 4 times, was ineffective in eliminating B equi-carrier infection in 9 mature geldings. A single IM administration of 4 mg/kg was not therapeutic in acutely infected splenectomized ponies. When given at 3 different dosages and treatment schedules, parvaquone was ineffective in clearing carrier infection. Parvaquone given IM once at a dosage of 20 mg/kg was effective for acute B equi infections in splenectomized ponies; parasitemia began to decrease within 24 hours after treatment. Infections were not eliminated however, and within 4 weeks, secondary parasitemia and anemia developed. Of 4 ponies, 3 died of acute piroplasmosis.     

Comparison of the efficacy of enrofloxacin, imidocarb, and oxytetracycline for clearance of persistent Anaplasma marginale infections in cattle

This study compared enrofloxacin and imidocarb dipropionate treatments with an oxytetracycline regimen proposed by the World Organization for Animal Health for elimination of persistent Anaplasma marginale infections in cattle. The effect of therapy on competitive ELISA and polymerase chain reaction (PCR) reactivity was also assessed. Twelve A. marginale-infected carrier calves were randomly assigned to groups receiving either enrofloxacin (5 mg/kg IV q24h for 5 days), imidocarb (5 mg/kg IM twice, 7 days apart), or oxytetracycline (22 mg/kg IV q24h for 5 days). One calf infected with an Oklahoma isolate in the imidocarb group and one infected with a Virginia isolate in the oxytetracycline group failed to infect a splenectomized calf following blood subinoculation. Both became competitive ELISA negative by 44 days after treatment, but the imidocarb-treated calf remained PCR positive. None of the tested treatments reliably eliminated persistent A. marginale infections in all cattle. Furthermore, PCR was not a reliable means of determining the success of chemosterilization in calves.     

Pharmacokinetics of ceftiofur and metabolites after single intravenous and intramuscular administration and multiple intramuscular administrations of ceftiofur sodium to dairy goats

Twelve (12) lactating dairy goats (46–71 kg body wt at study initiation) were divided into four treatment groups and dosed with ceftiofur sodium at 1.1 mg ceftiofur free acid equivalents (CFAE)/kg or 2.2 CFAE/kg using a complete two route (intravenous, i.v.; intramuscular, i.m.), two-period crossover design, with a 2-week washout between injections. After another 2-week washout period, the goats were dosed with ceftiofur sodium i.m. for 5 consecutive days at either 1.1 or 2.2 mg CFAE/kg. The goats from the 2.2 mg/kg multiple dose group were dried off and the i.v. kinetic study repeated. After all injections, blood samples were obtained serially for determination of combined serum concentrations of ceftiofur and metabolites. After intravenous doses of 1.1 and 2.2 mg/kg, the harmonic means of the terminal phase half-lives were 171.8 and 233 min, respectively, for lactating does. The harmonic mean of the terminal phase half-life after an i.v. dose of 2.2 mg/kg in non-lactating does was 254 min. The AUC _0–∞ was significantly less and the clearance significantly greater during lactation. After i.m. doses of 1.1 and 2.2 mg/kg, the harmonic mean terminal phase half-lives were 163 and 156 min, respectively. The i.m. bioavailability of ceftiofur sodium in goats was 100%, and the AUC _0–∞ was dose-proportional from 1.1–2.2 mg CFAE/kg body weight. After five daily i.m. doses of ceftiofur sodium at either 1.1 or 2.2 mg CFAE, there was minimal accumulation of drug in serum as assessed by C _max, and serum concentrations were dose-proportional after the multiple dosing regimen.     

The efficacy of albendazole against some gastrointestinal nematodes in goats

On the basis of worm counts in naturally infected Angora-X goats, albendazole at either 3.8 mg/kg repeated after 24 hours or as a single dose at 7.6 mg/kg, was >99% effective in removing adult Ostertagia and Trichostrongylus spp. Small numbers of adult Haemonchus contortus, Cooperia sp. and Chabertia ovina were present in control but not treated animals. The single dose of 7.6 mg/kg removed >99% of adult Oesophagostomum venulosum whereas the repeated dose of 3.8 mg/kg removed only 96%.     

Experiences with the use of Imizol in treating canine blood parasites in Nigeria

Imizol* (imidocarb diproprionate 12 per cent w/v) at 5 mg/kg body weight was found to be highly effective in the treatment of canine babesiosis, mixed infections of Babesia canis, Hepatozoon canis and Ehrlichia canis, but slightly less effective against uncomplicated Ehrlichia canis infections.