Die Zellzahl in der Frühlaktation - ein Gesundheitsmerkmal?

During a three-year period (2010 to 2012) within the project BHNP (breed for health neo-partus) data on various indicators for health status were collected for 15,273 calvings of Holstein cows from seven large herds in Germany. Within our project, it was attempted to measure cell counts during the early colostral phase, i.e. within the first five days after parturition. However, due to the field study nature of the project, samples obtained varied with respect to the day collected post-partum. In total, 8,447 samples with an average collection day of 5.3 p.p. and a range between 0 to 20 days p.p. were obtained. Noting that cell counts from the early lactation in general are on a higher level than lactation cell counts, it was found that cows with cell counts above 400,000 show a drastic and highly significant increase in the probability for a later treatment for udder health. For early cell counts below 100,000, between 100,000 and 400,000, and above 400,000, probabilities for a later treatment within the first 100 days of lactation increased from 20.32%, to 23.97%, and to 37.55% based on a mixed model analysis accounting for effects of herd-year-season and parity-age-at-calving. This finding was not due to an auto-correlation as herd managers were unaware of the results from the colostral phase samples. Probabilities for later treatment also corresponded to data for culling within the lactation. Estimates of heritabilities for SCSel (Somatic cell count in early lactation) were 0.23 when data was restricted to days in milk 0 to 4 only (n = 4,006 lactations) and 0.10 for the full data set (n = 7,483). In summary, the results confirm the use of somatic cell counts from the early lactation as a potential management tool and as a new trait for genetic selection. [ABSTRACT FROM AUTHOR]