The effect of bovine viral diarrhea virus introduction on milk production of Dutch dairy herds

Dairy cows are negatively affected by the introduction of bovine viral diarrhea virus (BVDV), and consequently, produce less milk. Existing literature on potential milk production losses is based relatively outdated data hardly evaluates loss in relation to a new BVDV infection surveillance system. This study determined annual quarterly 3,126 dairy herds participating Dutch BVDV-free program between 2007 2017. Among these herds, 640 were “breakdown-herds” that obtained subsequently lost their status during period, 2,486 retained period. Milk yields before after compared through linear mixed models. The fixed variables for both models included herd type (breakdown-herd or free-herd), (on an basis), year, season, random effect. dependent variable was average daily yield test day. To define possible BVDV-introduction dates, 4 scenarios developed. In default scenario, date breakdown (i.e., status) assumed as date. For other 3 scenarios, dates set at 4, 6, 9 mo breakdown, estimated birth persistently infected calf. due occurred mainly first year with reduction 0.08 kg/cow per day last breakdown. greatest second introduction, 0.09, 0.1 day, respectively. quarters 0.14, 0.02, These results indicated quarter introduction. Overall, had negative, but small, effect program. will enable farmers policymakers have clearer understanding quantitative farms control