Early detection of clinical and sub-clinical mastitis using an on-line electrical conductivity device in parlor.
M.Tinsky, M.Zagury,E.Peles, A.Saran, D.Feingold
Introduction
Mastitis is the most costly disease affecting daily cattle. Losses occur from decreased milk production, treatment and labor costs, non deliverable milk, veterinary fees, reduced milk quality, reduced milk price, increased risk of subsequent mastitis, culling and death of the cow(2). Such loss is caused by sub clinical mastitis, which has no visible apparent symptoms, Mastitis can be detected by applying one of the available screening tests, such as an on-line electrical conductivity (EC) measurement. Several studies have evaluated this method for sub-clinical and clinical mastitis detection. The object of this study was to evaluate the capability of the Afimilk system in detecting early mastitis.
Materials and Methods
The basic principle of this system is to check the maximal electrical conductivity of the milk. Each 200 cc of milk is checked while the milk flows through the milk-meter, and the highest value for each milking session (morning, noon and evening) is recorded in the cow's database. The system calculates the average conductivity for each milk fraction for the last 10 days, and compares it with the current milk conductivity. Cows that their milk conductivity deviates from their norm will be suspected of being infected, and a parlor alarm will point out the cow to be examined. In addition, the software can generate a health report (either on the computer screen or as a printer output for the farmer’s use. The health report (cow to check) allows the farmer to concentrate only on relevant data. This report includes cows showing any abnormal behavior like milk, production rate and activity, according to predetermined parameters and depending on the stage of lactation.
A study, which was started in the summer of 1991 in 3 commercial dairies, compared the EC on-line system to bacteriological and Nagase tests. In this study, every time a cow was suspected of being mastitic, a sample was taken aseptically, Frozen, and sent to the laboratory for bacteriological and Nagase analysis.
All the suspected cows in all the farms were detected first by the Afimilk system.
Results
The bacteriological analysis of the samples identified the Following pathogens. E, coli. S.aureus, Strepococci, Micrococci and Corynebacteria as shown in figures 4,5,6. In figures 1,2,3 the results of bacteriological and Nagase analysis are combined. The presence of pathogens (Pth+) or high level of Nagase (Nag+) or both, is a clear sign for mastitis or other inflammatory event.
Conclusions
Early studies that evaluated the on-line system considered it to be accurate for the detection of mastitis (1,3,4) In a study performed on the Afimilk system, pathogens were found in 73% of the samples first detected by the system. In this study the results of farm 1 fitted very well with those of Shoshani (4), i.e. about 75(% of the Afimilk system alarms were found positive. The bacteriological analysis of the samples from farm 2 showed only 42% correlation with the presence of pathogens, but in the Nagase test 100% of the samples were found having a high level, and all the cows from which the samples were taken showed clear external signs of inflammation. This was due to a leptospyrosis episode that was not screened in routine bacteriological tests. In farm 3 only 25% of the samples contained pathogens but again, high level of Nagase was found in all the samples, probably due to a short inflammation event. 97% of the samples had either pathogens or high level of Nagase. From these preliminary results it seems that the Afimilk system of early detection of mastitis is a reliable system. Research is continued to verify the statistical validity of the results.
References
1. Fernando R.S, S.L. Spahr and E.H. Jas Fr( 1985). Comparison of electrical conductivity of milk with other indirect methods for detection of sub-clinical mastitis, J Dairy Sci 68:440
2. Lighter J.K., G.Y. Miller, W.D Hucston and C K. Dorn (19S8). Estimation of the costs of mastitis using National Animal Health Monitoring System and milk somatic cell data. J. nm
Fig.1 (Full-size image) Fig.2 (Full-size image)
Fig.3 (Full-size image) Fig.4 (Full-size image)
Fig.5 (Full-size image) Fig.6 (Full-size image)
Fig.7(Full-size image)
