Claw health in organic and conventional dairy herds

Summary

Housing, management and production intensity are factors known to affect the claw status of dairy cows. Management and production intensity are generally also aspects that distinguish organic dairy herds from conventional. It is therefore possible that the claw health of organic and conventional dairy cows is different, but to our knowledge this has not been studied to any great extent. The aim of this study was therefore to investigate if there were differences in claw health status, recorded at routine claw trimmings, between organic and conventional dairy herds in Sweden. The data originated from a field study of 20 organic and 20 conventional dairy herds, where information on herd characteristics were collected by questionnaires administered at visits and from the official milk recording scheme. Data on claw health status was retrieved from routine recordings, but only trimmings from September 2005 to May 2006 was used in these analyses. Thus, records of 821 cows in 11 organic and of 755 cows in 12 conventional herds were used. A generalised linear mixed model with logistic link and herd included as a random effect, to account for clustering, was used to assess effects of explanatory factors on the individual cow risk for one or more lesions in any claw in any foot. Potential explanatory factors on herd level were type of herd (organic or conventional), stall type (free or tied), feeding regimen (total mixed ration or not), amount of roughage in early lactation, weeks at pasture during the preceding season, level of milk production and herd size, while potential explanatory factors on individual cow level were breed, parity, season at trimming and days in milk at trimming. Development of the multivariable model was by backward elimination of non-significant (p>0.05) effects. Overall, claw lesions were more prevalent in organic (34%) than in conventional herds (29%), but the within herd variation was substantial, i.e. 3 to 91% and 8 to 67% in organic and conventional herds, respectively. The overall prevalence of dermatitis was 6 and 3%, of heel horn erosion 14 and 17%, of sole haemorrhage 23 and 12%, and of sole ulcers 3 and 2% in organic and conventional herds, respectively. The final multivariable model included the effects of type of herd (p=0.3; forced into the model), feeding regimen (p=0.2; confounder), weeks at pasture (p=0.2; confounder), parity (p=0.001), days in milk (p=0.01) and season (p<0.001). Our results indicate that there is no significant difference in the overall risk for claw lesions between cows in organic and conventional herds.