Efficacy of using an internal teat sealer to prevent new intramammary infections in nonlactating dairy cattle.
OBJECTIVE
To determine whether insertion of an internal teat sealer (ITS) at the end of lactation would prevent development of new intramammary infections (IMIs) during the nonlactating period.


METHODS
Controlled clinical trial.


METHODS
939 Holstein-Friesian dairy cows from 16 herds.


METHODS
Results of bacteriologic culture of milk samples collected 14 days prior to the end of lactation were used to assign cows to groups (group 1 = negative results for all quarters; group 2 = positive results for > or = 1 quarter). Quarters of cows in group 1 were treated with an ITS or a single intramammary dose of cloxacillin; quarters of cows in group 2 were treated with cloxacillin in conjunction with an ITS or with cloxacillin alone. Milk samples were collected at the end of lactation and within 8 days after calving.


RESULTS
Regardless of whether the outcome of interest was new IMIs caused by any pathogens, major pathogens, environmental pathogens, or streptococci other than Streptococcus agalactiae, quarters in group 2 treated with both cloxacillin and an ITS were less likely to develop a new IMI than were quarters treated with cloxacillin alone. For cows in group 1, no significant difference in risk of new IMIs was found between treatments.


CONCLUSIONS
Results suggest that for dairy cattle with an IMI late in the lactation period, intramammary administration of cloxacillin at the end of lactation followed by insertion of an ITS enhanced protection against development of new IMIs, compared with use of cloxacillin alone.
Sanford
Carolyn J
CJ
Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE C1A 4P3, Canada.
Keefe
Greg P
GP
Dohoo
Ian R
IR
Leslie
Ken E
KE
Dingwell
Randy T
RT
DesCôteaux
Luc
L
Barkema
Herman W
HW