cow factors studied that had sufficient data to evaluate
significantly contributed to the heterogeneity of the
results. The estimated linear score (LS) of milk SCC
after calving in published studies (n = 3) and for studies
that provided raw data (n = 2), was significantly
lower for cattle treated with internal teat sealants and
ADCT in 3 studies than for cattle treated with internal
teat sealants only. The estimated LS of pooled raw data
of 3 studies from 32 herds showed that the LS of cows
treated with internal teat sealant and ADCT was not
significantly different than those treated with ADCT
only. This study found that the application of internal
teat sealants in the presence of ADCT or the use
of internal teat sealants alone at dry off significantly
reduced the incidence of IMI and clinical mastitis in
lactating dairy cows compared with respective control
groups. Further studies are needed to investigate the
effect of internal teat sealants on postpartum milk SCC
in lactating dairy cows.