A survey of biosecurity and health management practices on Irish dairy farms engaged in contract-rearing

A survey was conducted to investigate potential differences in biosecurity and health management practices on Irish dairy farms that sent their heifers for contract-rearing (source dairy farms, SDF; n = 62) and those rearing their own heifers (control farms, CF; n = 50). Participating farmers were surveyed by postal questionnaire between September and November 2018. The overall response rate was 93%. Results show that structurally, SDF were larger, less fragmented, and more specialized than CF. Outsourcing of labor-intensive activities to external contractors was more common among SDF than CF, exposing them to potentially increased biosecurity risks associated with animal movements, use of shared equipment, and increased frequency of farm visitors. The majority of SDF sent heifers to a single-origin rearing facility (70%), with heifers most commonly arriving at the rearing unit between 2 and 4 mo (53%) and returning to the dairy farm between 18 and 21 mo of age (56%). Despite the increased biosecurity risk associated with contract-rearing, implementation of disease prevention measures was not superior on SDF compared with CF. For both farm types, there was scope for improvement to visitor biosecurity protocols, quarantine procedures, colostrum feeding practices, and hygiene of calving areas. This research provides an overview of the demographics and farm management practices implemented by dairy farmers engaged in contract-rearing of replacement heifers, and will serve to inform farmers, veterinary advisors, and policy makers.

Bioexclusion of diseases from dairy and beef farms: risks of introducing infectious agents and risk reduction strategies

Infectious disease represents a major threat to the productivity and welfare of cattle herds throughout the world. The introduction of infectious agents into dairy and beef farms may be through direct transmission (purchased cattle, reintroduced resident cattle and contact with contiguous cattle) or indirect transmission (fomites, visitors, other species, and biological materials) and this article reviews the evidence supporting these transmission routes. In the absence of eradication programmes for many endemic infectious diseases, bioexclusion is the key management process for risk reduction. Various ameliorative bioexclusion strategies have been recommended and the evidence supporting these protocols is considered.