The objective of this study was to evaluate the prevalence of abnormal findings in gross necropsy, histopathology, and ancillary test results from neonatal beef calves submitted to a veterinary diagnostic laboratory.
This retrospective clinical case study was conducted by reviewing necropsy reports submitted between 2015 to 2020. Case inclusion criteria were animals had to be a bovine, 2 to 21 days of age, and a nondairy breed.
Gross necropsy, histopathology, and laboratory test results were recorded. Identified lesions and abnormal test results were categorized based on body systems and infectious agent type. Age and system affected were analyzed using a 1-way ANOVA and Bonferonni pairwise comparisons.
Overall, 1,060 reports were reviewed and 95 met the inclusion criteria. Median age of enrolled calves was 9 days (range, 2 to 21). A total of 252 lesions were identified with a median of 3 lesions/calf (range, 0 to 7) and 2 different body systems involved/calf (range, 0 to 5). The most common disorders were classified as digestive (42.1% [106/252]), respiratory (12.7% [32/252]), and multisystemic (11.1% [28/252]). With respect to age and system affected, calves with neurologic lesions were significantly younger (mean age, 5.1 days) than calves with digestive lesions (mean age 9.6 days).
These data suggest a high prevalence of infectious diseases, mainly digestive, respiratory and multisystemic in origin. These findings could help guide producers and veterinarians when assessing factors contributing to neonatal beef calf loss.
OBJECTIVE To compare the pharmacokinetics of 2 commercial florfenicol formulations following IM and SC administration to sheep.
ANIMALS 16 healthy adult mixed-breed sheep.
PROCEDURES In a crossover study, sheep were randomly assigned to receive florfenicol formulation A or B at a single dose of 20 mg/kg, IM, or 40 mg/kg, SC. After a 2-week washout period, each sheep was administered the opposite formulation at the same dose and administration route as the initial formulation. Blood samples were collected immediately before and at predetermined times for 24 hours after each florfenicol administration. Plasma florfenicol concentrations were determined by high-performance liquid chromatography. Pharmacokinetic parameters were estimated by noncompartmental methods and compared between the 2 formulations at each dose and route of administration.
RESULTS Median maximum plasma concentration, elimination half-life, and area under the concentration-time curve from time 0 to the last quantifiable measurement for florfenicol were 3.76 μg/mL, 13.44 hours, and 24.88 μg•h/mL, respectively, for formulation A and 7.72 μg/mL, 5.98 hours, and 41.53 μg•h/mL, respectively, for formulation B following administration of 20 mg of florfenicol/kg, IM, and 2.63 μg/mL, 12.48 hours, and 31.63 μg•h/mL, respectively, for formulation A and 4.70 μg/mL, 16.60 hours, and 48.32 μg•h/mL, respectively, for formulation B following administration of 40 mg of florfenicol/kg, SC.
CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that both formulations achieved plasma florfenicol concentrations expected to be therapeutic for respiratory tract disease caused by Mannheimia haemolytica or Pasteurella spp at both doses and administration routes evaluated.