Influence of claw health on fertility and milk production in dairy cows : an epidemiologic study from farms situated on the Aland Islands

Sammanfattning: Lameness and claw lesions are frequent health problems observed among dairy cows and are a common reason for culling, reduced milk production and reproductive inefficiency. The present study investigated the association between claw health, reproduction and milk production of dairy cows at the Aland Islands in order to gain an understanding of the current situation. The study included data from 17 farms during the years 2013 and 2014 regarding claw health, reproduction, milk production and housing system. Five of the herds kept the cows in free stalls and 12 herds kept the cows in tie-stalls. The recorded claw lesions were divided into infectious diseases and laminitis related diseases. Dermatitis, digital dermatitis, heel horn erosion, interdigital hyperplasia, wart growth, and interdigital phlegmone were considered as infectious diseases. Sole hemorrhage, sole ulcer, double sole, white line fissure, toe abscess, white line abscess and chronic laminitis, on the other hand, were considered as laminitis related diseases. Each disease was given a severity score depending on its clinical severity. The higher the total score a cow got the worse were the claw health. In the statistical analyses all trimming sessions for each cow were compared so that only the most severe score was used. This resulted in each cow having a maximum score for infectious diseases (maximum infectious point, MIP), a maximum score for laminitis related diseases (maximum laminitis point, MLP) and a maximum score for these two added together (maximum total point, MTP). Five parameters were studied in order to evaluate the effect of claw health on reproduction and milk production; number of services (inseminations), interval from first service to last service (IFLS), interval from calving to last service (ICLS), calving interval (CI) and mean ECM production. Fifty per cent of the total number of trimmed cows during 2013 had no recorded claw lesions; the same number in 2014 was 52 %. No significant correlations between year of production and MIP, MLP and MTP could be observed. Laminitis related diseases were more common on all farms compared to infectious diseases and a difference in the prevalence of both laminitis related diseases and infectious diseases could be observed between farms. There were significantly more infectious diseases on farms with free stall systems compared to farms with tie-stalls during both years (P=0.000 and P=0.016). A significant difference in the occurrence of laminitis related diseases between the claw trimmers was found. There were no significant differences between tie-stalls and free stalls herds concerning number of services, IFLS, ICLS, CI and mean ECM production. Average ECM production was not affected by an increase in MTP, MIP or MLP and there were no tendencies for more services, longer ICLS or longer CI with increased MTP. There was however a tendency towards a positive correlation between IFLS and MTP. The anecdotal evidence that dairy cows on the Aland Islands have better claw health than their counterparts in Sweden can neither be proved nor rejected based on the results from this study. The present study was an epidemiologic study, to draw conclusions about cause - effect relationships are therefore impossible. However, the results from this study can hopefully be a base in the future works towards a better claw health status at the Aland Island.