Biomedical subjects
Publications and source records attributed to O C Sampimon.
On 6 Dutch dairy farms cows died of an acute, very serious mastitis caused by Pseudomonas aeruginosa. This happened shortly after drying off with antibiotics. Before drying off the teat ends were cleaned with teat wipes contaminated with Pseudomonas aeruginosa.
The cycle of the warble fly, the possibilities for detection and treatment and the prevalence in Europe are described. In the Netherlands in 1953 a warble fly law was enacted. The eradication of warble fly in the Netherlands was completed in the early eighties. Therefore prevention of a reinfestation is necessary by control of imported cattle and of farms along the border with Belgium and Germany.
The choice of dry cow antibiotics should be based on clinical efficacy studies. The choice also depends on the sensitivity pattern of S. aureus, and the expected length of the dry period. There are many quarter, cow and herd factors that influence efficacy of dry cow therapy. These factors include somatic cell count, front-versus-hind quarter, age, and the number of infected quarters in a cow. Nutrition of cows at the end of the lactation and hygienic conditions on the farm and off are also important. The effect of extra treatments at dry off are questionable.
The objective of this study was to determine the factors that were associated with the cure of subclinical mastitis caused by Staphylococcus aureus treated during lactation. One hundred forty-three quarters that were infected with S. aureus were available from a number of treatment trials. Analysis of these data showed that the most important factors associated with cure were age of the cow, somatic cell count at the time of treatment, presence of the infection in the front quarters, and stage of lactation. Other factors, such as number of infected quarters per cow and sensitivity or resistance of the strain to penicillin, were not significant. Because of the relatively low probability of cure, it is important to know risk factors for cure and, hence, to choose cows for treatment with great care. Using these data, a prediction equation was developed to determine the cure rate of subclinical mastitis caused by S. aureus when treated during lactation.
Data from five dry cow antibiotic therapy trials were analyzed. Records were only included for cows with > or = 1 culture-positive quarters that were subclinically infected with Staphylococcus aureus. Data for 406 quarters affected with S. aureus from 283 cows on 73 farms were analyzed for quarters, cows, and herds. The probability of cure of an infected quarter decreased when SCC increased, when another quarter was infected in the same cow, when the infection was in a hind quarter, and when the percentage of samples that were positive for S. aureus was higher before drying off. Variables predicting complete bacteriological cure of a cow were log SCC, age of the cow, and the number of infected quarters. The probability of a cure decreased as SCC increased. The probability of cure decreased as age increased, and cows with more than one quarter infected were .57 times less likely to be cured than cows with 1 infected quarter.