Christine Brenninkmeyer

Risk factors for lameness in freestall-housed dairy cows across two breeds, farming systems, and countries.

Lameness poses a considerable problem in modern dairy farming. Several new developments (e.g., herd health plans) strive to help farmers improve the health and welfare of their herd. It was thus our aim to identify lameness risk factors common across regions, breeds, and farming systems for freestall-housed dairy cows. We analyzed data from 103 nonorganic and organic dairy farms in Germany and Austria that kept 24 to 145 Holstein Friesian or Fleckvieh cows in the milking herd (mean = 48). Data on housing, management, behavior, and lameness scores for a total of 3,514 cows were collected through direct observations and an interview. Mean lameness prevalence was 34% (range = 0-81%). Data were analyzed applying logistic regression with generalized estimating equations in a split-sample design. The final model contained 1 animal-based parameter and 3 risk factors related to lying as well as 1 nutritional animal-based parameter, while correcting for the significant confounders parity and data subset. Risk for lameness increased with decreasing lying comfort, that is, more frequent abnormal lying behavior, mats or mattresses used as a stall base compared with deep-bedded stall bases, the presence of head lunge impediments, or neck rail-curb diagonals that were too short. Cows in the lowest body condition quartile (1.25-2.50 for Holstein Friesian and 2.50-3.50 for Fleckvieh) had the highest risk of being lame. In cross-validation the model correctly classified 71 and 70% of observations in the model-building and validation samples, respectively. Only 2 out of 15 significant odds ratios (including contrasts) changed direction. They pertained to the 2 variables with the highest P-values in the model. In conclusion, lying comfort and nutrition are key risk areas for lameness in freestall-housed dairy cows. Abnormal lying behavior in particular proved to be a good predictor of lameness risk and should thus be included in on-farm protocols. The study is part of the European Commissions Welfare Quality project.

Hock lesion epidemiology in cubicle housed dairy cows across two breeds, farming systems and countries

This cross-sectional study examined various aspects of cubicle design and management in terms of their potential as risk factors for hock lesions, using an epidemiological approach. Cubicle dairy farms in Germany and Austria with Holstein Friesian or Simmental cows were visited during the winter housing season. 105 farms and 3691 cows were included in the analysis which consisted of three steps: bifactorial regression, regression trees and multiple linear regression. The mean farm prevalence of hock lesions, i.e. scabs, wounds, and swellings was 50%, with a range from 0 to 100%. The final model contained eight factors which were largely related to lying comfort and explained 75% of the variance. The presence of a curb turned out to be the most influential beneficial factor. Additionally, there were fewer hock lesions when cows were housed with deep bedded cubicles compared to cubicles without deep bedding. Other factors in the regression model were softness and length of the lying surface and height of free space under cubicle partitions, the proportion of overconditioned cows and a variable encoding three different combinations of region, husbandry system (organic and conventional) and breed. Independently from the risk factor model hock lesions were positively correlated with lameness at herd level as well as at animal level. This probably results from related risk factors for both conditions. It can be concluded that lying comfort of dairy cows should be improved in order to prevent hock lesions. In addition, preventive measures for hock lesions at the same time have a potential of reducing lameness and thus to improve cow welfare in several aspects.

Prevalence and magnitude of helminth infections in organic laying hens (Gallus gallus domesticus) across Europe

Helminths are associated with health- and welfare problems in organic laying hens. The present observational cross-sectional study therefore aimed to estimate the prevalence and worm burdens of intestinal helminths in organic flocks of laying hens in 8 European countries, and to identify management factors that might be associated with helminth infections, with emphasis on Ascaridia galli. Data on flock-level management factors (e.g. nutritional factors, litter quality, housing system, opening- and closing hours of popholes, pasture rotation and provision of occupational materials) were collected during a farm visit when the hens were on average 62 weeks old. Worm counts were performed for 892 hens from 55 flocks and the number of ascarid (presumably primarily A. galli) eggs per g faeces (EPG) for 881 hens from 54 flocks. The association between parasitological parameters (prevalence, worm burden and EPG) and the management factors were analysed by multivariate models. Results showed that A. galli was highly prevalent across Europe with an overall mean prevalence of 69.5% and mean worm burden of 10 worms per hen. The overall mean prevalence and worm burden for Heterakis spp. were 29.0% and 16 worms per hen, respectively, with a large variation between countries. On average, the hens excreted 576 ascarid EPG. The mean prevalence of Raillietina spp. was 13.6%. A positive correlation was found between mean A. galli worm burden and ascarid EPG. Of the analysed management factors, only pasture access time had a significant negative association with A. galli worm burden which was in contrast to the general belief that outdoor access may increase the risk of helminth infections in production animals. In conclusion, the complexity of on-farm transmission dynamics is thus a challenge when evaluating the relative importance of management factors in relation to helminth infections.

Feather-pecking and injurious pecking in organic laying hens in 107 flocks from eight European countries

Feather-pecking and cannibalism may reduce the potential of organic husbandry to enhance the welfare of laying hens. We report risk factors for these issues based on a large survey of 107 commercial flocks in eight European countries. Information was collected regarding housing, management and flock characteristics (age, genotype). Near the end of lay, 50 hens per flock were assessed for plumage condition and wounds. Potential influencing factors were screened and submitted to a multivariate model. The majority of the flocks (81%) consisted of brown genotypes and were found in six countries. Since white genotypes (19%) were found only in the two Scandinavian countries, a country effect could not be excluded. Therefore, separate models were made for brown and white genotypes. Feather damage in brown hens could be explained by a model containing a lower dietary protein content and no daily access to the free range (30% of the variation explained). For feather damage in white hens, no model could be made. Wounds in brown hens were associated with not having daily access to free range (14% of the variation explained). Wounds in white hens were explained by a model containing not topping-up litter during the laying period (26% of the variation explained). These results suggest that better feeding management, daily access to the free-range area and improved litter management may reduce incidence of plumage damage and associated injurious pecking, hence enhancing the welfare of organic laying hens. Since this was an epidemiological study, further experimental studies are needed to investigate the causal relationships.