s. mazza 1* n. guzzo1,2 & r. mantovani 1 -...
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Geneticcorrelationsbetweenmorphologicalfactorsandtestdaymilkin
Valdostana RedPiedbreedS.Mazza 1*, N.Guzzo1,2 &R.Mantovani 1
1 DepartmentofAgronomyFoodNaturalresourcesAnimalsEnvironment,UniversityofPadova,Legnaro (PD),Italy2DepartmentofComparativeBiomedicineandFoodScience
VALDOSTANABREED
• Dual purpose breed• Good longevity and fertility• Resistance to common diseases• Good adaptability to different climates
AOSTA RED PIED
Registered Cows 12,834
Average Milk Yield 4,000 kg
-Fat 3.56%
-Protein 3.24%
ADG 1 kg/d
Dressing Percentage 63%
SEUROP Score R(+)/U(-)
EAAP2014,Copenhagen(Denmark)– 27/08/2014– SerenaMazza
AOSTA RED PIED
Measured by linear type traits
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SELECTIONINDEX
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MORPHOLOGICALTRAITS
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MORPHOLOGICALTRAITS
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Theinfluenceoftypeonherdlifecanbeseveraly overstimated whentheestimationisbasedonalargenumberoftypetraits
TO AVOID THIS…
‘’ONLYALIMITEDNUMBEROFTYPETRAITSSHOULDBEUSEDINTHEINDIRECTESTIMATION’’
(Visscher,1994)
FACTORANALYSISTomaintainthevariabilitycontributedbyeachtrait,atthesametimetoreducethenumberofvariablestobemanaged
(Foraboscoetal.,2005)
FACTORANALYSIS
Factor1 Factor2 Factor3Frontfleshiness 0.85Back,LoinsandRump 0.88Thigh,Buttockssideview 0.88Thigh,Buttocksrearview 0.89Foreudderattach 0.68Rearudderattach 0.80Udderwidth 0.79Udderdepth 0.74SuspensoryligamentTeatplacementrearview 0.38TeatplacementsideviewTeatlength ‐0.48
Coefficient≥|35|
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FACTORANALYSIS
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Nowadays lactationmodel
REPEATABILITYMODELS
• Subsequentcontrolsinthesamelactation
• Geneticevaluationsbasedontest‐day(insteadoflactation)datacanaccountforenvironmentalinfluencesmoreaccurately
TESTDAYMODEL
Toestimategeneticparametersandcorrelationsbetweenmilkyieldrelatedtraitsand
morphologicalfactorsregardingspecificregionofthebodyofanimalsbelongingtothesmall
autochthonouspopulationofValdostana RedPieddualpurposebreed
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AIMOFTHESTUDY
MORPHOLOGICALDATASET TESTDAYMILKDATASET
33,206records 33,206animals 61,378animals inpedigree
169,008testday 16,605animals 41,991animals inpedigree
FINALDATASET202,214 records36,019animals
(13,792animals withboth MORPHandTD)61,912animals inpedigree
FACTOR1 fleshiness traitsFACTOR2 dimensional udder traitsFACTOR3 udder conformation traits
FATcontent (kg)PROTEINcontent (kg)MILK(kg)
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MATERIALS&METHODS
Morphological Model:yijkl =µ+HYCi+ACj+DIMk+al+eijkl
Where:yijkl =lineartypetraitµ =overallmeanHYCi = fixedeffectoftheherd‐year‐classifier
(7,475levelsforARP)ACk = fixedeffectofageatcalving
(5classes: from22to29mo,30‐34mo,35‐36mo,37‐41mo and≥42mo)DIMj = fixedeffectofdaysinmilk
(7classes:10‐30d,from31to180daftercalvingusing30‐dintervalsand≥181dforthelastclass)
al = randomadditivegeneticeffectofcoweijkl = randomresidualterm
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MATERIALS&METHODS
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Repeatability TestDay Model:yijklmno =µ+HTD(nl)i+Gestj+ lxAC(nl)k*+ lxMP(nl)l*+PEwm+PEbn+ao+eijklmno
Where:yijklmno =milk‐relatedtraitµ =overallmeanHTD(nl)i =fixedeffectoftheherd‐testday withinlactation
(46,722levels)Gestj =fixedeffectofdaysofgestation
(16classes:from1to210dofgestationusing15‐dintervalsand≥211dforthelastclass)AC(nl)k =fixedeffectofageatcalvingwithinlactation(42classes)MP(nl)l =fixedeffectofmonthofparitywithinlactation(36classes)PEwm =randompermanentenvironmenteffectwithinlactationPebn =randompermanentenvironmenteffectbetweenlactationao =randomadditivegeneticeffectofcoweijklmno =randomresidualterm
*ascovariates;Shapeofthelactationcurvedescribedby
4th orderLegendrepolynomials(Strabel andMisztal, 1999):
l1=1,l2=x,l3=(3x2‐1)/2,l4=(5x3‐3x)/2;xlactationdaysonastandardscale
of5‐305DIM
MATERIALS&METHODS
FACTOR TRAITS σ2a σ2r h2(SE)
1‐ Frontfleshiness‐ Back,Loins& Rump‐ Thigh,Buttockssideview‐ Thigh,Buttocksrearview
0.250 0.550 0.31(0.02)
2‐ Foreudderattach‐ Rearudderattach‐ Udderwidth
0.130 0.650 0.17(0.01)
3‐ Udderdepth‐ Teatplacementrearview‐ Teatlength
0.163 0.667 0.20(0.01)
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RESULTS_1Heritability estimates
TRAIT σ2pe σ2a σ2r h2(SE)
MILK(kg) 0.004 0.002 0.006 0.20(0.02)
FAT(kg) 0.003 0.001 0.002 0.13(0.02)
PROTEIN(kg) 3.554 1.311 1.740 0.17(0.02)
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RESULTS_2Heritability estimates
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Factor 1Fleshiness
Factor 2Udder size
Factor 3Udder conformation
Factor1 ‐0.38 0.21
Factor2 ‐0.09 ‐0.12
Factor3 0.06 0.08
RESULTS_3Genetic (above)andphenotypic (below)
correlations between factors
0.03≤SE≥0.06
MILK(kg) FAT(kg) PROTEIN (kg)
MILK(kg) 0.79 0.87
FAT(kg) 0.79 0.86
PROTEIN(kg) 0.91 0.77
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RESULTS_4Genetic(above)andphenotypic(below)correlationsbetweenmilkyieldtraits
0.01≤SE≥0.02
MILK(SE) FAT(SE) PROTEIN (SE)
Factor 1Fleshiness
‐0.53(0.11)
‐0.44(0.13)
‐0.41(0.11)
Factor 2Udder size
0.89(0.03)
0.83(0.04)
0.86(0.09)
Factor 3Udder
conformation
‐0.34(0.09)
‐0.23(0.10)
‐0.31(0.09)
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RESULTS_5Bivariategeneticcorrelationsbetweenfactorsandmilkyield
MilkyieldrelatedtraitsfortheValdostana RedPiedbreedshowedlowbutnormalheritabilityvalues(from13%to20%)
• Positiveandhighgeneticcorrelations(≥83%)betweenF2andmilkrelatedtraits
• MediumnegativegeneticcorrelationsofF1andF3withallthemilkrelatedtraits
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Fleshinessfactor(F1)isthemostheritabletrait(31%)
NegativegeneticcorrelationsofUddersizefactor(F2)withbothFleshinessfactor(F1)andUdderconformationfactor(F3)
CONCLUSIONS
National Association of Breeders of Valdostana cattle
Regional Association of Valdostana breed