Comparison of J5 Vaccinates and Controls for Incidence, Etiologic Agent, Clinical Severity, and Survival in the Herd Following Naturally Occurring Cases of Clinical Mastitis

Abstract

Holstein dairy cattle in 3 commercial herds were randomly allocated to J5 vaccination (n = 251) or untreated control (n = 306) groups. There were 221 new cases of clinical mastitis (CM) affecting 120 cows. Coliform mastitis cases had a higher percentage of severe quarter swelling or signs of systemic illness among control cows but not among J5 vaccinates, in comparison to noncoliform cases. Culling or death from CM affected 13 controls (4.3%) and 4 vaccinates (1.6%), with losses occurring earlier in lactation among controls, a higher hazard (probability of a cow dying on each day of lactation) for controls than vaccinates. The J5 vaccination was significantly associated with protection from culling for mastitis among the 15 Klebsiella cases; 2 out of 10 (20%) Klebsiella-infected controls were culled and 0 out of 5 vaccinates were culled. Cows in second lactation were at reduced hazard of culling for mastitis compared with older animals, even when adjusting for effects of J5 vaccination. When all CM cases (including subsequent new cases during the same lactation and multiple quarters or pathogens within the same cow on the same day) were evaluated, for the 221 cases of CM, the rate was significantly higher among vaccinates than controls (0.10 and 0.07 cases/30 d in milk, respectively). This was because J5 vaccinates had more subsequent new cases of CM in the same cow than controls. Pathogens isolated, which included mainly environmental bacteria, were not different among J5 vaccinates and controls. Immunization with J5 was associated with protection against severe clinical coliform mastitis signs, culling, and death loss from CM but not with any reduction in overall CM.

Association ofEscherichia coliJ5-Specific Serum Antibody Responses with Clinical Mastitis Outcome for J5 Vaccinate and Control Dairy Cattle

“…Associations between J5 vaccination of cattle, various measures of clinical severity of CM, and J5-specific antibodies have rarely been reported for naturally occurring cases of CM (2,17,19,23). Use of survival (time-to-event) analysis to evaluate the relationships between J5 vaccination, antibody production, and time until culling or death has recently been reported for the first time (23). Time-to-event analysis as a measure of incidence of disease or any other event of interest precisely accounts for the time at risk for each animal for that event (5).…”

“…The commercially available vaccines are often called J5 core antigen vaccines, but the antigen(s) and mechanism(s) of J5 immunization have not been clearly identified (2,23). Associations between J5 vaccination of cattle, various measures of clinical severity of CM, and J5-specific antibodies have rarely been reported for naturally occurring cases of CM (2,17,19,23). Use of survival (time-to-event) analysis to evaluate the relationships between J5 vaccination, antibody production, and time until culling or death has recently been reported for the first time (23).…”

Utilização da vacina Escherichia coli J5 na imunização de novilhas leiteiras contra mastites causadas por E. coli

“…Esse tipo de mastite caracteriza-se por alta incidência de casos clínicos, geralmente de curta duração, frequentemente com manifestação sistêmica e com maior frequência nos momentos pré e pós-parto imediato, coincidindo com o período de imunossupressão (Green et al, 2007). Os prejuízos relacionados aos casos clínicos de mastite por coliformes incluem desde redução na produção de leite até morte do animal, que ocorre em 10% dos casos mais severos (Wilson et al, 2007;Chaneton et al, 2008).…”

“…Uma estratégia importante para o controle da mastite é o aumento da resistência do animal por meio de imunizações (Wilson et al, 2007). A maioria das vacinas comerciais é composta por uma cepa mutante da Escherichia coli, a cepa E.coli J5.…”

“…Estudos controlados, na Europa e nos Estados Unidos, demonstraram a eficiência da imunização de animais com E.coli J5, não somente no que se refere à ocorrência de novas infecções intramamárias e de casos clínicos de mastite, mas também quanto à intensidade deles (Hogan et al, 1992;Wilson et al, 2007). No entanto, verifica-se que as condições de produção e, consequentemente, os fatores de risco em rebanhos brasileiros são bastante distintos em relação aos de outros países.…”