Application of bromsulphalein (BSP) fractional clearance test to dairy cows has been studied.
Basically, 2 mg of BSP per kg of body weight was injected at a steady rate into the jugular vein of dairy cows and blood samples were collected at short intervals of time for 30 minutes following the injection. BSP was exponentially and inversely eliminated from the blood and the log e of dye concentration was rectilineally related to time after administration. When a dose of BSP was injected within a certain range of body weight (a dose of 1.5 g BSP with body weight ranging from 600-850 kg, 1.0 g: 350-650 kg, 0.5 g: 200-400 kg, 0.3 g: 80-250 kg and 0.2 g: 30-120 kg), the rectilinearity of the data for all of the cows was very good over the general time interval from 5 to 12 minutes, which indicated that the mode of elimination of the dye was adequately expressed by a first-order reaction. Practically, the stable and limited BSP-t/2 value in minutes was calculated from the clearance curve drawn on basis of the semilogarithmic plot of dye concentration and time by sampling above three times (usually three times) during 5 to 12 minutes after the injection. The results of BSP-t/2 value and BSP percent retention (BSP-PR) in cows with acute hepatosis from CCl
4 intoxication varied progressively in adequate correlation with the changes of serum enzyme activities regarding liver functions. BSP-t/2 value was significantly correlated with BSP-PR at 20, 30 and 45 minutes after injection with reference to BSP-PR at 45 minutes (PR
45)(a correlation coefficient between t/2 values and PR45 values:γ=0.971, P>0.001).
In order to investigate the excretion of BSP into urine and milk, two lactating dairy cows were injected intravenously with 2.0 g of BSP. Only 1.22 % of BSP given was excreted in the urine, but no BSP was detected in the milk even after 48 hours.
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