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  • Author or Editor: E. D. Janzen x
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Objective

To determine the association between a leak of sour natural gas (more than 30% hydrogen sulfide) from a pipeline in a river valley and the health of beef cattle in the intensively ranched surrounding area.

Design

Prospective cohort study.

Sample Population

13 herds of cattle within 4 km (2.5 miles) of the leak and 10 herds outside the 4-km zone.

Procedure

Distance of herds from the leak site was determined, using geographic information system technology. Information about speed and direction of winds was obtained from a local meteorologic station and an ambient air-quality monitoring trailer. Health and productivity data for surrounding beef herds, as well as exposure information, were collected and analyzed.

Results

An association was not found between total herd calf mortality and herd distance from the leak, wind-aided exposure, location in the river valley, signs of irritation consistent with exposure to the gas, or reports of odors of gas at the time of the leak. Management changes reported in response to the gas leak were identified as risk factors for total herd calf mortality. Other herd-level risk factors associated with increased calf mortality ratio included a median calving date in February and percentage of twin births for a herd.

Clinical Implications

In this example, we did not detect an association between productivity of cattle and exposure to sour natural gas. Several methods can be used for ranking potential exposure after discovery of a leak. (J Am Vet Med Assoc 1998;212:41–48)

Free access
in Journal of the American Veterinary Medical Association

Summary

Plasma concentration of penicillin G was evaluated in beef steers after administration of either a combination of benzathine penicillin G and procaine penicillin G in a 1:1 mixture at a dosage of 9,000 U/kg of body weight, im (n = 5), 24,000 U/kg, im (n = 5), or 8,800 U/kg, sc (n = 5), or benzathine penicillin G alone at a dosage of 12,000 U/kg, im (n = 7). Plasma concentration of penicillin G was measured by use of a high-performance liquid chromatography assay that had a limit of determination of 0.005 µg/ml. At a dosage for this combination of 9,000 U/kg im, and 8,800 U/kg, sc, which are approved label recommendations in Canada, and the United States, respectively, mean (± sem) peak plasma concentration was 0.58 (± 0.15) and 0.44 (± 0.02) µg/ml, respectively. Although plasma penicillin concentration was quantifiable for 7 days in the steers that received 9,000 U/kg, im, and for 4 days in the steers that received 8,800 U/kg, sc, the concentration was < 0.1 µg/ml in both groups after the first 12 hours. After administration of the combination at dosage of 24,000 U/kg, im, there was an initial peak plasma concentration at approximately 2 hours; thereafter, plasma concentration decreased slowly, with half-life of 58 hours. Although plasma penicillin G concentration was quantifiable for 12 days at this dosage, concentration was < 0.1 µg/ml after the first 48 hours. After the initial 48 hours, plasma concentration of penicillin was of similar magnitude and decreased at similar rate for the combination at dosage of 24,000 U/kg and for 12,000 U/kg of benzathine penicillin G alone. Most of the plasma penicillin G concentration in the first 24 hours after administration of a 1:1 combination of benzathine penicillin G and procaine penicillin G is attributable to absorption of procaine penicillin G. After the first 48 hours, most of the plasma drug concentration appeared to be produced by absorption of penicillin G from benzathine penicillin G. Absorption of benzathine penicillin G produces quantifiable plasma penicillin G concentrations for several days, but they are below the level of susceptibility for most bacteria.

Free access
in American Journal of Veterinary Research