A total of 5852 records concerning daily milk yield, content of protein and fat, and somatic cell count was recorded in two farms (organic and conventional). Somatic cell count was log10- transformed before analysis because was not normally distributed. The mixed model methodology was used according to a repeated-measures scheme, as the restricted maximum likelihood method to estimate lactation curves at different season of calving and at different calving order. Calving order affected milk yield only in the first three calving order with the lowest production levels in the first six months of the year for both farm;no effect could be observed on fat and protein contents. The organic farm shows the minor milk production (7.77 vs8.10 kg/day/head organic and traditional respectively), but good qualitative characteristics of milk, and minor content of Somatic Cell Count. The milk production is major, in traditional farm, in summer respect the winter (10.4 vs6.34 kgof milk/day/ head). In biological farm no difference between seasons were observed. Peak milk yield occurs, for both farms, at around the 6th - 7th wk of lactation.
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