Masters Theses

Date of Award

6-1985

Degree Type

Thesis

Degree Name

Master of Science

Major

Comparative and Experimental Medicine

Major Professor

Robert D. Walker

Committee Members

Albert T. Ichiki

Abstract

Antibiotic levels in the serum and uterine fluid were determined following systemic and intrauterine administration of procaine penicillin G, amoxicillin, oxytetracycline (Liquamycin 100) and long acting oxytetracycline (Liquamycin LA-200). In this study it was determined that serum levels of each antibiotic were significantly greater following intramuscular administration than intrauterine administration. Following intramuscular administration, detectable levels of antibiotics were measured in the uterine fluids in all of the cows treated with amoxicillin, tetracycline and long acting tetracycline but in only 2 of 6 cows treated with procaine penicillin G. The levels in the uterus were below the minimal inhibitory concentration (MIC) for common uterine pathogens for the tetracycline preparations but remained above the mean MIC for Corynebacterium pyogenes, the most common cause of bovine endometritis for up to 36 hours after administration of amoxicillin.

Intrauterine administration of antibiotics resulted in more consistent levels of antibiotics in the uterine fluid and these levels persisted above the mean MIC for up to 36 hours for all common uterine pathogens. Absorption of antibiotic from the uterus into the serum was more consistent with amoxicillin and long acting oxytetracycline than with procaine penicillin G and oxytetracycline. However, in at least one cow treated with each of the antibiotics by the intrauterine route, no measurable levels of antibiotic were detected in the serum.

It was considered Important that the antibiotic should be absorbed or secreted Into the uterine lumen to ensure penetration Into the deep as well as superficial layer of the endometrium In the clinical treatment. As this did not occur to a great extent in these animals the optimal treatment of the condition may Involve the treatment by both the Intramuscular and intrauterine routes.

It was originally Intended that cows should be in the luteal phase of the cycle for the entire experiment. The heat periods of the cows were synchronized with prostaglandin PCF 2α. Each cow was to act as her own control in a series of eight experiments using the four drugs by two different routes—Intramuscular and Intrauterine and that experiments would not be scheduled during the periods when cows would be in the estrous phase of the cycle. However, following Infusion early estrus was induced. This resulted in experiments having to be carried out at different stages of estrous cycles. Blood samples were analyzed for progesterone levels to determine the stage of the cycle. Sufficient numbers were not present in each group to deter mine If the stage of the cycle had an effect on absorption and secretion of antibiotics.

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