期刊名称：Archivos Latinoamericanos de Producción Animal
出版年度：2005
卷号：13
期号：02
页码：56-62
出版社：Latin American Association of Animal Production
摘要：The objective of this study was to analyze the effect of somatic cell scores on functional longevity (FL) assessed using survival analysis. Longevity was measured as days of productive life. Functional longevity was obtained by global longevity correcting for milk production. Data of production and somatic cell count (SCC) consisting of records from 20.359 Spanish Holstein cattle, with date of first calving between 1988 and 2000. Factors included in the Weibull model were: herd-year-season of calving (HYS), age at first calving (AFC), lactation number-stage of lactation (NS), annual change in herd size (CHZ), milk (MY), fat (FY) and protein (PY) yield. All the effects were significant (P<0.0001) with HYS and NS those as that more contributed to explain the differences on the relative risk of culling (RR), followed by MY and contributed to explain the differences on the relative risk of culling (RR). An increase in the SCC levels caused a greater RR. An important effect of SCC and udder depth in FL was observed. Cows with greater SCC had almost 4.0 times more RR and it was more evident in very deep udders animals.
