Table 2.

Dynamics of antibody status to bovine coronavirus (BCV) and bovine respiratory syncytial virus (BRSV), in pooled milk samples from five primiparous cows from 79 dairy herds in four areas in Sweden, stratified by the results of the first sampling in primiparous pools and in bulk tank milk (BTM). The results relate to six sampling points between October 2006 and April 2009.

	Result at first test BTM/primiparous pool	Negative throughout study	New exposure - remained positive	New exposure - returned to negative	Multiple new exposures (fluctuated)
BRSV (n = 4)	- / -	100%	0%	0%	0%
BRSV (n = 12)	+ / -	41.7%	33.3%	8.3%	16.7%
BCV (n = 2)	- / -	100%	0%	0%	0%
BCV (n = 9)	+ / -	22.2%	66.7%	11.1%	0%
		Positive throughout study	Turned negative - remained negative	Turned negative then new exposure	Multiple new exposures (fluctuated)
BRSV (n = 64)	+ / +	50.0%	33.3%	16.7%	0%
BCV (n = 69)	+ / +	59.4%	13.0%	27.5%	0%