Quantifying intraherd cattle movement metrics: Implications for disease transmission risk

Area of Science:

• Veterinary Epidemiology
• Animal Health Management
• Disease Transmission Dynamics

Background:

• Limited data exists on how on-farm cattle movement and grazing patterns influence biosecurity and disease transmission.
• Understanding these dynamics is vital for managing chronic infectious diseases like bovine tuberculosis (bTB).

Purpose of the Study:

• To quantify on-farm cattle movement practices, including pasture use and time spent grazing.
• To assess the relationship between these management practices and herd risk for bovine tuberculosis (bTB).

Main Methods:

• Collected daily cattle movement data from 18 farms over one grazing season (n = 18,988 grazing days).
• Analyzed stocking densities, frequency of pasture movements, land fragmentation, and movement distances.
• Correlated these attributes with herd bTB risk and historical bTB breakdowns.

Main Results:

• Dairy herds had higher stocking densities and more frequent pasture movements than beef herds.
• Beef cattle spent more time on fragmented land and moved between more pastures.
• No analyzed farm or herd attributes were directly associated with new bTB breakdowns during the study period.

Conclusions:

• While current grazing practices were not linked to new bTB breakdowns, historical breakdowns showed weak associations with movement distance and fragmented land use.
• Further research should investigate the role of intra-herd grazing patterns in disease transmission models.
• Increased focus on intra-herd movement dynamics is needed for effective bTB control strategies.