Eric Cahuzac

Perinatal, neonatal, and rearing period mortality of dairy calves and replacement heifers in France

Dairy calf and replacement heifer mortality in France was assessed by calculating mortality rates at 0 to 2d (calves), 3d to 1 mo (calves and heifers), 1 to 6 mo of age, and 6 mo of age to first calving (heifers) using the national identification database. Between birth and 2-d-old, 261,000 and 251,000 of the 3.56 and 3.43 million calves born in 2005 and 2006, respectively, died. The overall 0- to 2-d-old calf mortality rate was around 6.7%, which is similar to the low range of values reported in the literature. Among the 2.38 and 2.39 million calf-month, 139,000 and 133,000 died between 3d and 1 mo of age in 2005 and 2006, respectively. Among the 3d to 1 m of age group, dairy calf mortality rate was around 5.7%. Such a rate has not been reported previously because of the great differences in age classes between studies. For the 0- to 2-d-old and 3-d- to 1-mo-old calves, annual mortality was zero on 26 and 44% of the farms, respectively. Calf mortality during the first month of life increased in winter (to 12-17%) and decreased in summer (to 8-12%), with a small peak in June or July. Mortality during the first month of life is higher in males than in females, with a mortality odds ratio of 1.20 (and 95% confidence interval of 1.19-1.21). Such a difference is also found within the noncrossed or beef-crossed calf subpopulations. Disregarding the sex, the mortality of beef-crossed calves is slightly less than that of noncrossed dairy calves, with a mortality odds ratio of 0.98 (and 95% confidence interval of 0.98-0.99) before 1 mo of age. In heifers, around 51,000, 35,000, and 40,900 out of the 1.2 million 3-d- to 1-mo-old, 1.1 million 1- to 6-mo-old, and 950,000 6-mo-old to first calving heifers died, respectively. The respective mortality rates were 4.5, 3.1, and 4.1%; these rates are similar to the low range of values previously published. The proportions of farms with no heifer mortality during a year were higher than for calves, between 60 and 70%. The mortality probability for heifers was very high for the first day of life (95% survival between 2-30 d of age), then decreased during the first year of life and became constant up to around 3 yr of age (88% survival at 36 mo of age). The risk of mortality is higher in Montbéliarde and Normande heifers compared with Holstein. In conclusion, and beyond the average mortality rates, farmers and farm advisors should keep in mind the broad range of mortality values, which shows that very low mortality (1-2%) can be achieved, even in animals with a known high risk of mortality, such as beef-crossed dairy calves.

Herd-level and contextual factors influencing dairy cow mortality in France in 2005 and 2006

Dairy cow mortality causes financial loss and is increasing over time; it indicates suboptimal herd health or welfare. To describe the herd-level and contextual factors affecting cow mortality, the French National Bovine Dataset Identification was used to create dairy, beef, or fattening units within farms, for 2005 and 2006. Mortality rate (MO-RA, outcome variable) and most variables were calculated at the unit level, whereas contextual variables were defined at the municipality level [cattle density, inhabitant density, agricultural land always with grass on overall agricultural land (ALWG/OAL)]. The localization (11 dairy production areas, representative of the farming systems) was also included. The statistical analysis was performed with a probit regression model (MO-RA=0 or>0) and with a linear model corrected by the Heckman method for bias sample selection. For 2005 and 2006, 3.8 and 3.7 million dairy cow-years, 101,445 and 96,954 dairy units, and 141,677 and 143,424 deaths were recorded, respectively. Over one-third of the units had no dairy cow mortality in 2005 or 2006. Overall MO-RA was 3.7 and 3.8% for 2005 and 2006, respectively. Restricted MO-RA (farms without death excluded) was 5.8% for 2005 and 2006. The correlation of MO-RA among units between the 2 yr was 0.25. The same effects and close estimate values were reported for 2005 and 2006 with both models. Mortality rate was positively associated with the number of cow-years, having a beef unit in addition to a dairy unit, the proportion of purchased cows, the proportion of first-calving cows, the average calving interval, being a Milk Control Program member, inhabitant density, not being in dairy production area Grand-Ouest, and ALWG/OAL. Negative associations were reported for breed other than Holstein, being a Good Breeding Practices member, having a calving peak in autumn, culling rate, and municipal cattle density. This study reports an average mortality rate for the French dairy cows. It suggests that the farmers management style highly influences mortality. In addition, farming system has an effect on the mortality. A possible association between municipal intensification of production and decreased mortality was also reported.

Factors influencing dairy calf and replacement heifer mortality in France

Herd-level risk factors for dairy calf and heifer mortality in France were identified by calculating herd-level variables (including mortality risk or rate) using the National Bovine Identification Database (2005 and 2006). Eleven dairy production areas representing different livestock systems were also included. Statistical analyses were based on a probit model (mortality risk or rate=0 or >0) and a linear model (mortality risk or rate >0) corrected by the sample bias Heckman method. The same associations were reported for 2005 and 2006. The mortality risks or rates for calves and heifers were positively associated with the proportion of purchased cows or being a Milk Control Program member and negatively associated with adhering to the Good Breeding Practices charter and having an autumn calving peak. The associations between mortality and the breeds or the production areas were positive or negative, depending on the classes of animal. Mortality and having a beef herd in addition to the dairy herd were negatively associated for noncrossed birth to 2-d-old calves, noncrossed 3-d- to 1-mo-old calves, and 3-d- to 1-mo-old heifers. Having a beef herd probably provides specific know-how related to newborn and young calf management that makes it easier to attain low mortality in pure-breed dairy calves. The proportion of males born was positively associated with mortality for the birth to 2-d-old calves (all classes) and for the 3-d- to 1-mo-old beef-crossed calves, but negatively for all classes of heifers. This indicates that heifer management was improved when the availability of newborn heifers decreased, resulting in low mortality. This lower mortality is apparent for all classes of heifers present on the farm during the year when the proportion of males was low, and demonstrates an anticipatory effect. In conclusion, this study shows that the presence of a beef herd in addition to the dairy herd within a farm is associated with decreased dairy calf mortality. It also shows that heifer mortality decreases when the proportion of heifers born decreased. These determinants of dairy calf and heifer mortality are of great importance for farmer advisors, the dairy industry, and the political decision makers.

Localisation de l’agriculture biologique et accès aux marchés

L’objectif de cet article est de contribuer a l’analyse des implications sur la localisation du developpement de l’Agriculture biologique (AB), souvent analyse en termes de « conventionnalisation ».

Hiring difficulties and manpower flows: does labour market density matter?

We analyse the impact of density on labour markets when firms and workers are heterogeneous. Using the results of a survey carried out in the French Midi-Pyrénées region, we show that, for comparable sizes and sectors, recruiting firms in low-density areas experience more difficulties in finding workers meeting the requirements of the jobs, especially since being usually located far away from large urban agglomerations, they appear to hold little attractiveness for potential migrants. As a consequence, they recruit less and the competition between firms on the local labour market is reduced. This, in turn, contributes to lessen the hiring difficulties for firms that do post vacancies in low-density areas. The labour market density therefore has opposite effects on the causes of hiring difficulties, but we show that its overall impact on the frequency of those difficulties for firms which hire is negative. Finally, because they are less likely to find a better match than their current job, employees living in low-density local labour markets have a lower tendency to resign than other workers do. As a consequence, turnover increases density.

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

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.