VARIATION IN IMMUNE RESPONSE BETWEEN CANADIAN PUREBRED HOLSTEIN & NORWEGIAN RED CROSSBRED CALVES &...
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Transcript of VARIATION IN IMMUNE RESPONSE BETWEEN CANADIAN PUREBRED HOLSTEIN & NORWEGIAN RED CROSSBRED CALVES &...
VARIATION IN IMMUNE RESPONSE BETWEEN CANADIAN PUREBRED HOLSTEIN & NORWEGIAN RED CROSSBRED CALVES
& FIRST CALF HEIFERS
March 12, 2010
Shannon Cartwright
Norwegian Red X Holstein (NRFX) Holstein (HO)
Antigen Response
Pathogen type
Examples of disease
Type 2 Antibody-mediated immune response
Extracellular
Mastitis caused by Staph aureus
Type 1 Cell-mediated immune response
Intracellular
Bacterium that causes Johnes disease
Heifer Immunization Protocol
Day 0 Day 7 Day 9
(6-9 Days post calving) Day 14
-collect blood -collect blood -final skin-fold
-immunize -skin-fold measurements measurements
type 1 & 2 antigens -intra-dermal injections
-immunize human serum albumen (HSA)
-collect blood
1° for HSA3° DTH
Evaluation of AMIR
• Sera obtained from blood samples taken on days 0, 14 and 21 for calves and days 0, 7 and 14 for heifers
• Antibody activity to test antigens is determined by ELISA (Begley et al. 2009)
Control Test
Summary Calf Results
• Crossbreds had significantly greater primary IgG and IgM antibody response
• Significant farm*breed interaction for secondary IgG antibody response - on farm where effect of breed significant crossbreds had greater antibody response
• No difference in DTH response between breeds
• Results indicate crossbred calves may have enhanced defence against extracellular pathogens
Conclusion
• Crossbred calves significantly greater AMIR therefore enhanced defence against extracellular pathogens
• Crossbred heifers significantly greater AMIR & CMIR therefore enhanced defence against extracellular & intracellular pathogens during peripartum period