Non-vaccinated Cows Research Articles

Risk assessment on the importation of milk and milk products (excluding cheese) from countries not free from foot and mouth disease

The authors discuss the risk assessment conducted by the Australian Quarantine and Inspection Service (AQIS) on the importation of milk and milk products (excluding cheese) from countries not free from foot and mouth disease (FMD). This assessment was undertaken in response to requests from countries wishing to export dairy products for sale on the Australian market. AQIS conducted a public consultation on the proposal, in line with Australian Government policy on transparency and accountability in the quarantine decision-making process. The authors examine the procedures involved in the investigation of the likely presence of FMD virus in milk of vaccinated and non-vaccinated cows, and of the heat treatment parameters effective in the inactivation of the virus. The data provide a useful aid in the assessment of the risk factors associated with the importation of milk and milk products, and in the development of quarantine conditions for importation.

Production of Brucella abortus-specific protein A-reactive antibodies (IgG2) in infected and vaccinated cattle

The IgG2 anti-Brucella antibody response of cattle to Brucella vaccination and infection was measured. Three groups of animals were studied; Group 1 contained 11 non-vaccinated cows, Group 2, 17 cows vaccinated with a low dose of Strain 19 vaccine and Group 3, 17 cows vaccinated with a high dose of Strain 19 vaccine. All animals were challenged at Week 33 with an infectious isolate of B. abortus (Strain 2308). Studies of the IgG2 antibodies response indicated an absolute correlation between anti-Brucella IgG2 levels and infection of the animal. All animals showing reciprocal titers of ⩾3000 (16 of 45 tested) were found to be positive for the challenge organism at slaughter. Animals with reciprocal IgG2 titers ⩽1000 (29 of 45 tested) were found to be negative for the challenge organism at the time of slaughter. The predictive value of IgG2 antibody levels for infection held for animals in all three groups and consequently this suggests that monitoring of specific IgG2 anti-Brucella antibody levels may be of value in detection of Brucella-infected cattle.

Antibodies to [formula omitted] in sera from strain 19 vaccinated and non-vaccinated cows as determined by enzyme linked immunosorbent assay and conventional serologic methods

The sensitivity of an enzyme linked immunosorbent assay was compared with 4 other serologic methods for detecting antibodies in B. abortus vaccinated and non-vaccinated cows. Antibodies were detected by ELISA in sera from more than 93% of the culture positive cows, however, less than 55% of the infected animals were identified by any other serologic method. Similarly, antibodies were detected in 82% of the culture negative cows by the ELISA method.

Vaccination of pregnant cows with low doses of Brucella abortus strain 19 vaccine.

Two groups, each of 9 Jersey cows, were vaccinated subcutaneously with reduced doses of Brucella abortus strain 19 vaccine (measured by the number of bacteria in the vaccine dose) early in their second pregnancy. Ten weeks later they were challenged, along with a similar group of non-vaccinated cows, by conjunctival instillation of a virulent strain of B. abortus biotype 1. Cows in Group 1 received 1/20th and those in Group 2 received 1/400th the recommended dose of strain 19. Marked reduction in the serological response to vaccination was seen only in Group 2. Four cows in Group 1 excreted strain 19 after parturition, one of them aborted and another calved prematurely with heavy infection of the placenta and foetus with strain 19 in both cases. Resistance to challenge was similar in both vaccinated groups, and higher than previously demonstrated after conventional calfhood vaccination with strain 19. It is concluded that pregnant cows can be effectively vaccinated by the subcutaneous administration of a dose of strain 19 vaccine containing approximately 3 x 10(8) organisms without undue interference with subsequent serological tests or inconvenience resulting from persistence of strain 19 infection.

Immune Response to Toxic Staphylococcal Cellular Products and Efficacy of Mastitis Therapy Treatment

Experimental staphylococcal mastitis was inducible in both nonvaccinated and vaccinated cows by intramammary infusion of sterile inflammatory agent containing cultural products from a bovine strain of Staphylocoocus. Infusion of 10ml of inflammatory agent containing 10 international units of α-hemolysin provoked an inflammatory response, with overt symptoms closely resembling those of clinical mastitis. Vaccinated and nonvaccinated cows appeared equally susceptible to the experimental mastitis. This mastitis elicited a systemic immune response in nonvaccinated cows.Neither equivalent nor multiequivalent infusions of homologous bovine antiserum lessened the severity of experimentally induced mastitis in vaccinated and nonvaccinated cows. This was true when the antiserum was infused immediately after the inflammatory agent or six hours later. Moreover, the antiserum alone sometimes provoked an inflammatory response.

A Macroglobulin (12 S) Agglutinin for Brucella Bovine Milk1,2

Since milk from cattle infected with Brucella abortus may contain specific agglutinins for Brucella, milk is now widely used in several presumptive tests to detect brucellosis-suspicious herds. In the brucellosis eradication program, some herds have been encountered in which the milk of a single animal reacted in high dilution to the Ring Test (13), yet blood serum from these animals did not give significant reactions to the tube agglutination test (1) and repeated attempts failed to isolate Brucella from the milk of these individual cows. Studies to determine the nature and cause of this phenomenon resulted in the isolation of a macroglobulin (12 S) agglutinin for Brucella from milk and the development of a procedure which appears to differentiate this agglutinin from those observed concurrently with the isolation of Brucella abortus.The 12 S Brucella agglutinating component has been isolated from two nonvaccinated cows (No. 2002 and 2159) of the type described above, which were obtained from herds with a history of no Brucella infection during the previous 4 yr.

Experimental Studies on the Occurrence of Staphylococcal Antitoxin in the Whey of Cows

SUMMARY Antitoxin was not detected in the whey of non-vaccinated cows until 3 days after experimental infection of the udder with staphylococci. In cows vaccinated with an adjuvant cell-toxoid prepared from Staph, aureus strain 201 and subjected to mammary challenge with the homologous strain, antitoxin appeared in the whey within 6 hours of infection. Mammary inoculation of vaccinated cows with 10 ml. distilled water also induced a rapid occurrence of antitoxin in the milk. It is concluded that some degree of irritation of the mammary epithelium is necessary before circulating antitoxin can pass into the milk.