Klövhälsa registrerad vid rutinmässig verkning i lösdrift eller uppbundna system med ekologisk eller konventionell mjölkproduktion

Abstract: KRAV-certified organic dairy herds generally have a lower milk yield than conventional dairy herds. A high-level of milk yield requires a feeding regime with high amounts of concentrates, a factor known to contribute to the development of claw lesions (Bergsten, C. 2003). The aim of this study was to compare claw health between organic and conventional dairy herds in free and tie stall systems. The number of herds from different domestic animal health associations was chosen in proportion to the association´s total portion of Swedish dairy producing herds of each type, respectively. Data, from Swedish Dairy Association (Svensk Mjölk) database on claw health status retrieved from recordings at routine claw trimmings from the control years 2005-2006, regarding the prevalence of claws without lesions, heel horn erosions, sole haemorrhages and sole ulcers was used in the statistical analysis. Although not significant, it seems like KRAV-certified dairy herds in loose housing systems generally had a better claw health with a greater proportion of claws without lesions compared to conventional herds (67,1 % versus 55,7 %). They also had fewer records of heel horn erosions (11,6 % versus 22,8 %), of sole haemorrhages (21,3 % versus 24,2 %) and of sole ulcers (3,0 versus 5,6 %). In the observed tie stalls the situation was the opposite: conventional dairy herds had throughout, amongst both first calf heifers and multiparous cows, a higher prevalence of claws without lesions (69,5 % versus 49,7 %, P<0,03) and, taken together, a lower prevalence of both heel horn erosion (13,9 % versus 28,1 %) and sole haemorrhages (13,9 % versus 20,6 %). Heifers in KRAV-certified dairy herds had, though, a lower prevalence of sole ulcers compared to heifers in conventional tie stalls (4,6 % versus 6,5 %). Primiparous cows in organic tie stalls had a marginally higher prevalence of sole ulcers (6,8 % versus 6,3 %). There was a considerable difference between these results compared to the study of Manske et al. (2002 a) where only 28 % of the cows were free from recorded claw lesions. Sole ulcer was the only claw lesion that had nearly the same prevalence as Manske et al. (8,8 %) in both organic (2,9-6,8 %) and conventional (5,3-6,9 %)) dairy herds, irrespective of housing system. The reason for the differences is probably that the willingness to record the most frequent occurring claw lesions was lower compared to Manske et al. and not that the claw health in Swedish dairy herds has become remarkably better the past years. The reliability of the records made at routine claw trimming therefore becomes lower compared to when a specially educated person is judging disease symptoms as was also shown by Wells et al. (1993). The results do not point to the fact that there are any convincing differences in claw health between organic and conventional dairy herds. The differences can more likely be explained by other factors, i.e. environment, flooring, housing facilities, management and claw-trimming routines that have a much greater influence on the claw health than have the feeding strategy alone. The present study is strongly limited and shall be regarded as a pilot study, comparing organic and conventional dairy herds concerning differences in recorded claw health at routine claw trimming. To have more reliable results it is necessary to have a larger number of herds and to correct for confounders such as claw trimmer and breed. Data could be analysed on individual level if taken into consideration that they are clustered within herds. In such a model it is possible to analyse risk factors of both individuals and at herd level.