Effects on productivity and risk factors of Bovine Respiratory Disease in dairy heifers; a review for the Netherlands
Keywords:Bovine Respiratory Disease, heifer, BRD, risk factors
AbstractThis paper presents a literature review about the impact of Bovine Respiratory Disease (BRD) on the productivity of dairy heifers and about risk factors for the disease, as far as these are relevant to commercial dairy farming in the Netherlands. The review includes peer-reviewed publications over the period January 1980-June 2001 on field studies that quantified the variables of interest. The literature data show that BRD in dairy heifers increases the risk of mortality directly after the disease episode by up to 6 times and reduces growth during the first 6 months of life with up to 10 kg. In addition, the disease can increase mortality in later stages of the rearing period, and age and likelihood of dystocia at first calving. Other diseases in dairy heifers and herd size are clearly associated with the risk of BRD, and season and colostrum feeding management presumably affect this risk. Effects of other potential risk factors are less evident. In conclusion, although several associations were found, the data on the majority of the potential productivity effects and risk factors of BRD are ambiguous or incomplete. However, based on the literature data several recommendations for BRD prevention on Dutch dairy farms were made, which are discussed in this paper.