All Dairy Producers Want More Healthy Cows

The Problem• Difficult to improve genetically – low

heritability• Poor data quality & inconsistency in

disease diagnosis• Selection to fight one disease may be

counter-productive to other diseases

Increasing Incidence of Disease

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Repro (Metritis)Retained PlacentaRespiratoryLamenessMastitis

NAHMS Dairy 2007 Part II: Changes in the Dairy Cattle Industry 1991-2007

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What if…

• What if there was a way to genetically enhance disease resistance through improved overall immune response

• We could actually reduce the incidence of disease with each generation

Immunity+ Sires

• Bulls tested for immune response• Transfer high immunity to their

daughters• Daughters have lower incidence of

mastitis, metritis, retained placenta, Johne’s & other diseases

High Immune Response• Semex has exclusive rights to test bulls

using “High Immune Response Technology”

• Professor Bonnie A. Mallard (PhD)Department of PathobiologyOntario Veterinary CollegeUniversity of Guelph

What Does Immunity Mean?

Immunity Types

• Passive Immunity

• Innate Immunity

• Acquired Immunity

Passive Immunity• Initial and temporary

• Passed through colostrum

• Contains protective features from the dam

• Fades as own immune system matures

Innate Immunity

Innate Immunity

Core of immune system – First line of defense against harmful disease• Non-specific responses• No memory of past exposure

Two Types of Acquired Immunity

Cell Mediat

edAntibody Mediated

Fights intracellular infections

ex. Virus or mycobacterium that causes Johne’s

Fights extracellular infectionsex. Bacteria (mastitis)

Overall Immune Response

Immune Response

Balanced defense against all diseases – both viral & bacterial

Immune Response Genes

Disease

Selection for Immune Response

• Measuring strength & effectiveness of the overall immune response– Provides balanced attack between viral &

bacterial infections

– Strengthens both first & subsequent exposures to pathogens

– Feasibility of selective breeding due to high heritability

What is Heritability?

HeritabilityDefinition

Proportion of variation observed in a trait which is due to genetics

– Genetics vs. Management, feeding, housing & environment

Immune Response

Testing For High Immune Response

HIR Test Protocol

DAY 14

1. Cell: Take initial skin-fold measurement & surface injection

2. Antibody: Collect final blood for ELISA

DAY 15

1. Cell: Take final skin-fold measurement 24-48 hours

DAY 1

1. Antibody: Collect initial blood for ELISA

2. Antibody: Immunize intramuscularly with type 1 & 2 antigens

HIR test is a 15 day test that requires 3 farm visits:

15 Day Process

Exclusive Product At Semex

Bulls Designated as Immunity+

Approximately 10% of sires

Immunity+ Sires

• General improvement in overall immunity across the herd– More high immune response daughters– Daughters will pass on the higher immune

response

• Just like High Immune Response Cows– Less disease– Better immune response to vaccines– Better immune quality colostrum– Longer herd life

Immunity+ Sires

What’s The Significance of High Immune Response?

High Immune CowsHigh Immune Cows vs. Herd• 27% less Mastitis• 17% less Metritis• 32% less Retained Placenta

700 cows in 3,000 Cow Dairy in North Florida

• Range in all herds was 19–30% less incidence of disease (High vs. Herd)

Disease data from: Wagter et al. 2000 JDS 83:488 and De Lapaz, J. 2008 MSc Thesis, University of Florida.

Thompson-Crispi, K. et al., 2011 Technical Report to the Genetic Evaluation Board, Canadian Dairy Network

Immune Response vs Disease IncidenceAverage Incidence (combined diseases)

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16.00%

7.50%

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% D

isea

se O

ccur

renc

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High Average Low n= 64 herds

Better Response to Commercial VaccinesHigh Immune CowsRespond better to commercial vaccines

Lumens OF SERUM ANTIBODY TO J5 E. coli VACCINE

ELIS

A O

D

Reference: Wagter & Mallard et al 2000 JDS 83:488

Greater Antibody in Colostrum & Milk

Ref – Wagter & Mallard et al 2000 JDS 83:488wk 0 wk 2 wk 3 wk 4 wk 6

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High Immune CowsHave higher quality colostrum

with more antibodies

Economic Value of High Response Cows

+ Lower incidence of disease– Mastitis, metritis, ketosis, retained placenta, milk fever

+ Improved vaccine response+ Higher quality colostrum+ Lower cull ratesHigh Immune Cow vs. Herd Average Cow

Additional $124 per cow per year

Transmission to Daughters

25%– Heritability of high immune response

(proportion explained by genetics)

50%– Proportion of genes that sire passes on

to daughters

Future Research & Development

• Validation of health results in daughters of Immunity+ bulls

• Genomic studies for immune response

HIR Genome-Wide Association StudyObjective: To determine genetic profiles associated with enhanced IR

Methods: •Selective genotyping of High and Low immune respondersusing the Illumina Bovine SNP50•163 cows genotyped (81 HIR and 82 LIR)•Generalized quasi-likelihood score method •Minor allele frequency > 0.05•Minimum call rate > 0.85

Genomic markers for AMIR

Genomics of Immunity+• Chromosome 23 contains the Bovine

Major Histocompatibility Complex (BoLA) which is responsible for acquired immunity in cattle

• This confirms that HIR measurements are hitting the right target

• More than 2,000 genes involved• Could lead to HIR genomics in future

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Sire

Corrected Ab % Skin Thickness

First Bulls Tested at Semex

No adverse reactions and no cross-reactivity were found before and after HIR testing protocol

Immune Response Distribution

Immunity+ Bulls (9 Proven + 32 Genomax)

Sire ProofAverage -

Immunity+ Bulls

Advantage Over Tested Non-

Immunity+ BullsTPI 2106 +80

Net Merit $564 +$91

Productive Life 4.8 +0.8

SCS 2.76 -0.06 (favourable)

DPR +0.3 +0.5

Daughter Calving Ease 6.5 -0.2 (favourable)

Released on December 4, 2012

Contact us at:Immunity@semex.com