Biomedical subjects
Publications and source records attributed to C C Gay.
A method using the Doppler ultrasound principle for indirect determination of arterial blood pressure in the horse is described. The method is simple and suitable for field situations. Validation studies show that systolic and diastolic blood pressure measurements bear a close relationship to true values obtained by direct measurement.
Indirect arterial blood pressure was determined on 33 horses prior to surgical intervention for the diagnosis and/or correction of acute abdominal disorders and a relationship between low systolic blood pressure and non-survival was established. It is suggested that blood pressure determination should be used to augment other methods of clinical and laboratory examination in cases of equine colic.
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A total of 21 bovine fetuses was inoculated in utero with Escherichia coli antigen to determine if nonserotype-specific resistance to colisepticemia could be induced. (Seven of these fetuses were inoculated through the intact flank of the dam.) After birth, the calves were deprived of colostrum and challenge exposed to a serologically distinct E coli which killed nonvaccinated controls. Of 21 calves vaccinated as fetuses, 10 survived challenge exposure, 8 died of colisepticemia, and 3 were stillborn. Premature birth precluded an adequate period of vaccination in 6 of the calves that died of colisepticemia. A relationship was not observed between E coli serum antibody and survival after challenge exposure. The results indicate that in utero vaccination with a single serotype of E coli can result in heterogenetic protection against neonatal colisepticemia. However, the occurrence of stillbirth and premature birth in calves vaccinated in utero indicates need for furthur research before field application of this technique.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
We examined the relationship between serum gamma glutamyltransferase (GGT) activity and serum gamma immunoglobulin G (IgG1) concentration in Holstein calves. Blood samples were collected from calves aged 1 to 3 days. A follow-up sample was obtained from each calf 2, 7, or 15 days after the initial sampling. Serum GGT activity and IgG1 concentration were measured. Regression models were used to predict IgG1 concentration as a function of age and serum GGT activity measured 2, 7, or 15 days later. Serum GGT activity and calf age at the time of the second sample were directly related to serum IgG1 concentration in the initial sample in calves aged 3 to 17 days (r = .54) and in calves aged 3 to 10 days (r = .63). Models were used to estimate the serum GGT activity equivalent to a serum IgG1 concentration of 1,000 mg/dL. One-day-old calves should have serum GGT activities > 200 IU/L. Four-day-old calves should have serum GGT activities > 100 IU/L. One-week-old calves should have serum GGT activities > 75 IU/L. Calves with serum GGT activities < 50 IU/L should be classified as having failure of passive transfer.
The relationship between serum protein concentration in the 1st week of life and survival to 16 weeks of age was examined in 3,479 Holstein replacement heifers over a period of 10 years on a farm with endemic salmonellosis. Thirty-four percent of calves studied had serum protein concentrations < 5.0 g/dL and 60.5% of calves had serum protein concentrations < 5.5 g/dL. Cumulative mortality was 7.9%, indicating that calves with marginal passive transfer status can be reared successfully under conditions of endemic salmonellosis. Optimal survival was observed in calves with serum protein concentrations > 5.5 g/dL. Calves with serum protein concentrations of 5.0-5.4 g/dL had only a slightly increased relative risk (RR) of mortality (RR = 1.3) compared to calves with serum protein concentrations > 5.5 g/dL. The highest RR was experienced by calves with serum protein concentrations < 4 g/dL (RR = 4.6) and 4.0-4.4 g/dL (RR = 3.1). Calves with inadequate passive transfer (serum protein concentration < 5.0 g/dL), experienced increased mortality until at least 10 weeks of age, indicating that failure of passive transfer has an effect on calf health that extends into the juvenile period. Models in which serum protein concentration was treated with as a continuous variable or as a categorical variable failed to demonstrate any significant interaction between baseline mortality and the RR of mortality. This finding suggests that the RR derived in the present study should be applicable to farms with dramatically different baseline mortality rates.
This study developed a method to partition the risk of mortality in dairy calves in the 1st 16 weeks of life. Observed population mortality and the relative risk of mortality in each serum protein concentration stratum were used to determine the population baseline mortality rate and the mortality rate due to inadequate passive transfer of colostral immunoglobulin. A total of 3,479 calves were studied, 8.2% of which died before 16 weeks of age. The population baseline mortality rate was 5.0% and the mortality rate due to inadequate passive transfer was 3.2%. Thirty-nine percent of the observed mortality was attributed to inadequate passive transfer. This partitioning of risk between passive transfer-related and unrelated sources should prove useful in conducting investigations of calf mortality problems in dairy herds.