Depletion of florfenicol in lactating dairy cows after intramammary and subcutaneous administration
| Autor: | Y. Jones, J. C. Kawalek, Michael J. Myers, Karyn D. Howard, M. L. Scott |
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| Rok vydání: | 2015 |
| Předmět: |
Florfenicol
Veterinary medicine 040301 veterinary sciences Cmax Body weight 01 natural sciences Milking 0403 veterinary science chemistry.chemical_compound Milk yield Animal science Mammary Glands Animal Animals Pharmacology Thiamphenicol General Veterinary Chemistry Drug Administration Routes 010401 analytical chemistry food and beverages 04 agricultural and veterinary sciences 0104 chemical sciences Bioavailability Anti-Bacterial Agents Milk Cattle Female |
| Zdroj: | Journal of veterinary pharmacology and therapeutics. 39(6) |
| ISSN: | 1365-2885 |
| Popis: | Eighteen Holstein dairy cows ranging in body weight from 500-700 kg and with an average milk yield of 37 ± 6 kg/day were used to investigate the depletion of florfenicol (FFL) in milk and plasma of dairy cows. Three groups of six were administered FFL: Group A, intramammary (IMM) infusion of ~2.5 mg FFL/kg BW at three consecutive milking intervals (total amount of ~7.5 mg/kg BW); Group B, one IMM infusion (20 mg/kg BW) into one quarter and Group C, one subcutaneous (SC) treatment (40 mg/kg BW). IMM infusions were into the right front quarter. Cows were milked daily at 06:00 and 18:00 h. The highest concentrations (Cmax ) and time to Cmax (Tmax ) were: 1.6 ± 2.2 μg·FFL/mL milk at 22 h (Group A), 5.5 ± 3.6 μg·FFL/mL milk at 12 h (Group B), and 1.7 ± 0.4 μg·FFL/mL milk at 12 h (Group C). The half-lives (t1/2 ) were ~19, 5.5, and 60 h, for Groups A, B, and C, respectively. FFL was below the limit of detection (LOD) by 60 h in three Group B cows, but above the LOD at 72, 84, and 120 h in three cows. FFL was above the LOD in milk from Group C's cows for 432-588 h. Plasma values followed the same trends as milk. The results demonstrate that IMM-infused FFL is bioavailable and below the LOD within 72-120 h. The concentration of FFL was detectable in both plasma and milk over the course of 2-3 weeks after SC administration. The absence of residue depletion data presents problems in determining safe levels of FFL residues in milk and edible tissues. The data presented here must not be construed as approval for extra-label use in food animals. |
| Databáze: | OpenAIRE |
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