Table 2.

Overview for comparison of key features and progress of control programmes for BVDV, paratuberculosis and Salmonella Dublin in Danish dairy cattle farms up until June 30, 2021 (i.e., the information is non-exhaustive).

Key features of the disease control programmes	BVDV	Paratuberculosis	Salmonella Dublin
Main biosecurity measures	Avoid contact with cattle from other farms. Hygiene of instruments and other equipment used in different farms.	Reduce purchase of livestock; avoid cows' faecal contamination of calves' environment, especially at calving. Avoid use of milk and colostrum from test-positive cows.Cull repeat-positive.	Stop purchase from test-positive farms, rigorous hygiene and sectioning of animals in management groups to lower/stop transmission, good calf and calving management and hygiene. Pasteurisation of milk used in some farms. Culling of suspected carriers in some herds.
Test-strategies	Step wise testing of bulk tank milk, spot sampling of young stock and testing of individual animals.	Repeated testing using indirect ELISA on individual cows' milk from the milk recording system.Repeatedly test-positive cows culled if possible; all test-positives considered potentially infectious and measures to reduce transmission from these are pivotal.	Bulk-tank milk antibody tests every 3 months in all dairy herds, blood sampling at abattoirs or on-farm in non-dairy herds. Testing calves negative required before test-negative status of herd can be obtained. Bacteriological culture mainly used for herds with high risk or clinical suspicions, “salmonellosis.” In some herds, repeated testing used for detection of suspected carriers.
Mandatory/voluntary	Mandatory surveillance and control programme of all cattle herds. Legislation in place from early on and updated regularly.	Voluntary surveillance and control programme.	Mandatory surveillance and control of all cattle herd. Legislation in place from early on and updated regularly to target and strengthen control measures.
Feasibility	Requires focus on clarification of herd infection status and control of cattle movements.	Requires persistent focus on hygiene; testing can be used to identify high-risk animals to make the efforts risk-based. Uncertainty in test interpretation must be accepted.	Requires daily, persistent focus on hygiene, reduced animal contacts and follow-up for years. Challenging in large, multi-site farms with many animal movements. Some uncertainty in test interpretation must be accepted.
Prevalence/progress of programme	Since 2006: Zero or few sporadic cases per year after successful control programme.	June 2021: 60–70% of herds deemed infected; mean within-herd prevalences in herds in control programme <5%.	At surveillance initiation in 2002: 25% test-positive dairy herds. June 2021: 9% test-positive dairy herds.