A Model for Detection of Individual Cow Mastitis Based on an Indicator Measured in Milk

Abstract

A dynamic deterministic biological model was developed that generates, for a given cow on a given day, a value for her risk of having mastitis. The model combines real-time information from a mastitis indicator measured in milk with additional factors that are other known risk factors of mastitis but that are not reflected in the indicator. l-Lactate dehydrogenase (LDH), an enzyme whose activity is increased because of mastitis, is used as an example of a mastitis indicator. The additional factors incorporated in the model are days from calving, breed, parity, milk yield, udder characteristics, other disease records, electrical conductivity, and herd characteristics. The model is designed to run each time a new LDH value is recorded and can run in the absence of the additional factors. Electrical conductivity measurements and disease records, where available, also trigger the model to run. As an input, milk LDH activity values (micromol/min per L) are multiplied by milk yield (L) to produce the amount of LDH (micromol/min) and are then smoothed using an extended Kalman filter before being processed by the biological model. The output comprises a risk of acute mastitis and a relative degree of chronic mastitis. The model also produces a days-to-next sample value that allows sampling frequency to be either increased or reduced depending on the risk of mastitis. The days-to-next sample value was designed to make the best use of opportunities afforded by automated, inline sampling technology. The model functionality was investigated using simulated data, and real-farm data of naturally occurring mastitis were then used to validate the model. The results demonstrated that the model is robust to sampling frequency and random noise in the LDH measurements. It was able to detect mastitis reasonably well: Using a threshold mastitis risk of 0.7, sensitivity for detecting clinical mastitis was 82%. Specificity, that is, the ability to avoid misclassifying healthy observations as mastitis, was 99%.

Invited review: Sensors to support health management on dairy farms

“…The relation between the chosen indicator and a reference test has been studied for mastitis (Chagunda et al, 2006a). The models calculate a risk of disease and when a cow should be tested by the sensor system Chagunda et al, 2006b;Friggens et al, 2007). The model for estrus detection has been tested with real cow data (Friggens et al, 2008), and the economic effect of such a sensor system on the farm has been studied (Østergaard et al, 2005).…”

Enzyme activity and acute phase proteins in milk utilized as indicators of acute clinical E. coli LPS-induced mastitis

“…LDH activity may, in the in-line situation, be preferable due to analytical constraints connected with NAGase determinations. Consequently, mathematical models using LDH response in milk as predictors in in-line measurement systems have recently been developed (Chagunda et al, 2006b;Friggens et al, 2007).…”

Métodos Automatizados De Diagnóstico De Mastite Em Vacas Leiteiras: Uma Revisão

“…LDHA é um grande potencial para a detecção de mastite clínica (SUN, 2010). Segundo Chagunda (2006), um biosensor tem sido avaliado usando simultaneamente dados simulados e dados da propriedade, nos quais amostras de leite foram analisadas em um laboratório com resultados de bom desempenho, porém, apesar de estar disponível comercialmente seu desempenho não foi avaliado a campo (MAZERIS, 2010).…”