Correlations between milk production and kinetic variables in milk of cephalothin administered to lactating goats

The aim of the present study was to correlate the milk production and the kinetic variables in milk of cephalothin administered to goats. Twenty healthy creole goats in milk production were used. Cephalothin was administered by intravenous route (20 mg/kg b.w.). Milk samples were collected at 0.25, 0.5, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 8.0 and 12.0 hours postadministration of the antibiotic. Cephalothin concentrations were measured in milk samples by high performance liquid chromatography. The values (mean ± standard error) of milk production collected during 24 hours previous to the administration of the antibiotic were 761.5 ± 111.1 ml. The results of the kinetic variables (mean ± standard error) of cephalothin in milk were: AUC = 5.4 ± 1.6 µg/ml/h; Cmax= 1.1 ± 0.3 µg/ml and tmax = 1.7 ± 0.1 h. The correlation coefficients AUC-milk production, Cmax-milk production and tmax-milk production were: 0.602 (P < 0.01), 0.596 (P < 0.01) and 0.398 (P < 0.1), respectively. In conclusion, the areas under the curve and the maximum concentrations and the time to reach them in milk are in fact related to the volume of milk produced by the goats