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