Factors influencing average herd somatic cell count in France in 2005 and 2006

Abstract

To describe factors affecting composite weight mean cow SCC (CMSCC) in France, 5 models were used with yearly or monthly CMSCC (YE-CMSCC; MO-CMSCC) as explanatory variables: 2 linear models (2005 and 2006), a monthly static panel data model (24 months) and 2 dynamic panel data models (2005 and 2006). The average CMSCC was 266,000 cells/ ml. The correlation between 2005 and 2006 CMSCC was 0.69. 50, 33 and 10% of the units had a CMSCC >250, 300 and 400,000 cells/ml in 2005 or 2006, respectively. In linear and static panel data models, number of cows, having a beef or fattening unit, number of days in milk (DIM), age at first calving, purchased cow proportion, proportion of cows at risk for subacute ruminal acidosis (SARA) and negative energy balance (NEB), average calving interval and having at least one dead cow were positively associated with CMSCC, whereas the association was negative for a predominant breed other than Holstein, milk production, dry-period length, first calving cow proportion, having an autumnal calving peak, being a good-breeding practices member, the previous-year culling rate, the municipal cattle density and the municipality grass utilization. In the dynamic panel data models, MO-CMSCC was positively associated with previous and penultimate MO-CMSCC, penultimate SARA, previous milk production and current number of cows, DIM and NEB. A negative association was described for the 3rd previous month MO-CMSCC, current milk production and current proportion of first calving cows. This study showed the impact of SARA and NEB on CMSCC and the high importance of farmer’s motivations for udder health issues, among them the specialization of farmers into dairy production. The contextual factors including farming system, local milk payment conditions and cattle intensification had also an important effect on CMSCC. Dynamic approach appeared as a promising tool for both research and farm surveys.KeywordsSubacute Ruminal Acidosis (SARA)Static Panel Data ModelCurrent ProportionFarm SurveyNegative Energy Balance (NEB)These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.