Perinatal mortality in heifers - An emerging problem

Perinatal calf mortality rates in heifers are increasing internationally. This temporal trend is particularly apparent in dairy herds. Currently, up to 50% of Holstein-Friesian heifers on US dairies are assisted at calving and it is not uncommon to find herds with close to 20% calf loss in heifers. These data are particularly relevant to European dairy farmers, mutatis mutandis, given the on-going importation of genetics from North America. Evidence of this North American genotypic influence on perinatal mortality rates is already present in Europe. There are recent published reports of increasing perinatal calf mortality rates in heifers from Sweden, The Netherlands and Denmark. Surprisingly, increased calf loss in these countries has not been associated with increased dystocia. This suggests an innate calf viability problem possibly mediated via placental insufficiency. Recent Irish data indicate that currently perinatal calf mortality rates in heifers are stable. Though the current rate (8%) may not be as high as in North America, increasingly individual farmers report major outbreaks of calf loss in heifers. New Irish research to address this issue, including investigation of the epidemiology of calf loss and development of ameliorative strategies, is documented.