all dairy producers want more healthy cows
DESCRIPTION
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. %. - PowerPoint PPT PresentationTRANSCRIPT
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
1996 2001 20070
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10
15
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25
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35
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50
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)
0.00%
2.00%
4.00%
6.00%
8.00%
10.00%
12.00%
14.00%
16.00%
7.50%
11.30%
14.40%
% D
isea
se O
ccur
renc
e
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
0
0.5
1
1.5
2
2.5
3
HighAveLow
OD
ELI
SA
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
0.00
20.00
40.00
60.00
80.00
100.00
120.00
140.00
160.00
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
% In
crea
se in
Ski
n Th
ickn
ess
OD
Valu
e (1
/50
+ 1/
200)
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)