Relationship between individual-cow udder health status in early lactation and dairy cow characteristics in Brittany, France.

Data from a 4-year ecopathological survey involving 47 dairy farms in Brittany (France) were used to determine the individual animal characteristics associated with the udder health profiles of clinical and subclinical mastitis, and the presence of minor or major pathogens in milk during early lactation. Herd effect was taken into account and a within-herd analysis using factorial correspondence analysis and a decomposition of chi-square distance was performed. In primiparous cows, the main association observed was between milk production and intramammary infections with major pathogens. The dirtiness score showed contradictory relationships with udder health profiles. The indoor/outdoor transition period was unfavourable for udder health status; since the frequency rate of subclinical and clinical mastitis increased during this period. In multiparous cows, intramammary infections by minor or major pathogens were closely associated with non-infectious udder diseases, but the main effect was due to parity. Old cows were generally affected by higher somatic cell counts than younger cows regardless of whether the SCC were associated with clinical mastitis or not.

[Mortality of dairy cows in an ecopathologic survey in Brittany]. / La mortalité des vaches laitières dans l'enquête écopathologique Bretagne.

Although rare, natural death in dairy cows represents a serious economical loss. In a sample of intensive dairy farms, the mean yearly mortality rate was estimated to be 0.96%. There were various causes known (metabolic, accidental, calving-related, respiratory) and unknown (1/3 of the cases). No significant annual or seasonal variation was observed, although the beginning of the grazing period seemed to be associated with a higher mortality rate. The cows with a parity of 7 or more had a higher probability of dying (mortality rate: 3.5%). The post-partum period was also associated with a higher number of deaths. The inter-herd variability was significant, with mortality rates running between 0 and 4.24%. Nutritional diseases, digestive disorders and trauma were predisposing factors of natural death.

[Modeling the information system of a research program using the MERISE method: the example of an ecopathological survey on dairy cows]. / Modélisation du système d'informations d'un programme de recherches par la méthode MERISE: l'exemple d'une enquête écopathologique sur les vaches laitières.

We present the MERISE method for the design of an information system, detailing data modelling. An exploratory research program on peri-partum pathology in intensive dairy herds is used as an example. The information system is divided into thematic subsystems called 'fields', which are represented by a global conceptual scheme. For each field, a detailed conceptual model is then determined through precise modelling guidelines. This division facilitates the validation of models by the partners of the project, and makes it possible to re-use the fields in other research programs.