Use of internal teat sealant in heifers reduces mastitis and may affect milk production

Abstract

Mastitis in heifers is costly, affecting milk quality and reducing milk production throughout the first lactation. Several studies have reported the beneficial effects of internal teat sealants (ITS) on mastitis in heifers, but there appear to be no reports on the subsequent effects on milk quality and production. The consequences of using ITS before calving were examined in a retrospective study in which two cohorts of primiparous heifers (n = 189), treated with an ITS precalving, were compared with four cohorts when ITS was not used (n = 287), using detailed bacteriology and herd-test production data in a DairyNZ research herd. In years when ITS was used, fewer (P < 0.001) heifers were detected with an intramammary infection at the first milking after calving, and fewer (P < 0.001) cases of clinical mastitis were detected in the first 30 days of lactation, than in years when ITS was not used. During the first 8 weeks of lactation, heifers treated with ITS had a lower (P < 0.0001) somatic cell count and produced 49 kg more milk (P < 0.05) and 5 kg more milksolids (P < 0.001) than did non-treated counterparts. These positive benefits associated with use of ITS provide sufficient evidence to justify further investigation in the form of a prospective controlled study.