The objective is to evaluate the effects on animal health, welfare and longevity of extended lactations
in dairy cows based on cows and data from four dairy herds (WP2). Health will be evaluated
using recordings of disease treatments from the national cattle data base and clinical evaluations
of individual animals (including e.g. body condition, lameness and lesions) performed at
regular intervals. In addition, an extensive evaluation of animal welfare in the two groups of cows
(normal versus extended lactations) will be made. Longevity of animals in the two groups will be
evaluated based on information recorded on-farm combined with information from central databases.
Data will be analysed using complex statistical and epidemiological methods.

Expected outcome:
Cows with extended lactations will experience less „high risk periods? in relation to health problems
and it is therefore expected that extended lactations will have a positive effect on 1) health, 2)
welfare and 3) longevity of dairy cows.