Selecting milk composition and mastitis resistance by using a part lactation sampling design in French Manech red faced dairy sheep breed F. Barillet 1, J.M. Astruc 2, G. Lagriffoul 2, X. Aguerre 3, B. Bonaïti 4 1
INRA – UR 631 Toulouse, France 2 IE - Toulouse, France 3 CDEO Ordiarp, France 4 INRA – UR 337 Jouy-en-Josas, France 36th ICAR Session, Niagara Falls, USA, 2008
Génétique Animale 1
Breeding goals in French dairy sheep breeds
Roquefort area : LACAUNE breed Breeding goals : 50 % ( milk traits) + 50 % ( SCC (mastitis) & udder ) Plus PrP gene (scrapie resistance)
PYRENEEAN MOUTAINS MANECH RED FACED BREED
Breeding goals : 100 % milk traits Plus PrP gene (scrapie resistance) accounting in the future for SCC (mastitis) in Manech red faced breed 36th ICAR Session, Niagara Falls, USA, 2008 2
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BREEDING BREEDING SCHEME SCHEME IN IN MANECH MANECH RED RED FACED FACED (2001 (2001)) 210 flocks in AC recording
65,825 ewes
640 rams born from assortative matings
Nucleus flocks
220 rams in breeding centres of young rams
Animal insemination 1 AI centre (AI) 13,800 AI
130 sampling rams
400 rams
Commercial flocks
32,400 AI 90 proven rams
73 flocks in D recording 19,000 ewes 850 Flocks without recording / 150,000 ewes 36th ICAR Session, Niagara Falls, USA, 2008 3
Published estimates of genetic trend for milk yield in dairy sheep (milk yield expressed as mature equivalent lactation) (J.M. Astruc et al., 2002; A. Carta et al., 2004; A. Legarra et al., 2003)
Country
Breed
Period
Annual genetic trend % in population litres mean
AI rate in the nucleus flocks
FRANCE
Lacaune Manech (Blond-faced)
1986-1999 1986-1999
2.2 % 2.3 %
5.8 l 4.2 l
85 % 54 %
ITALY
Sarda
1990-2002
1.2 %
2.0 l
12 %
SPAIN
Latxa (Blond-faced) Latxa (Black-faced)
xxxx-2003 xxxx-2003
2.9 l 3.0 l
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Phenotypic, genetic and environmental trends in Manech red faced breed for milk yield (expressed in mature equivalent lactation) 190
Milk yield (litres)
Between 1985 and 2006 - Annual phenotypic gain : 5.4 litres - Annual genetic gain : 4.2 litres
170 150 130
L
110 90
96 97
94 95
Breeding Value
98 99 20 00 20 01 20 02 20 03 20 04 20 05 20 06
Milk yield (phenotype)
93
91 92
89 90
87 88
85 86
70
Flock x year effect
YEAR
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60
GENETIC TREND FOR MANECH RED FACED RAMS (animal-model evaluation)
5
40 30
3 2 1 0 -1
20
-2
Fat Content EBV
20 02
20 01
99 20 00
98
97
96
95
94
93
92
91
0
Protein Content EBV
-3 Now -4 on milk composition -5 20 04
Main effort on PrP selection
20 03
10
19 90
MILK YIELD (litres)
ANNUAL GENETIC GAIN bettween 1990 and 2004 4.0 litres for Milk yield - 0.28 g/l for Fat content - 0.11 g/l for Protein content
FAT AND PROTEIN CONTENT gl-1
4 50
YEAR OF BIRTH
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Evolution of the AI in Manech red faced breed according to the PrP genotype of the rams 70000 AI rams ARR/ARR The specific situation of the Manech red faced breed
Number of AI
60000
(specific for affected flocks)
50000
AI rams ARR/ARR
40000 30000
AI rams ARR/ARQ
20000 10000 0 2000
AI rams ARQ/ARQ
2001
2002
2003
2004
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Milk composition and SCC recording (1/2)
Part-lactation sampling design already used in Manech red faced (MRF) breed for milk composition: fat and protein contents
Since 2002, part-lactation sampling design implemented in first lactation also for somatic cell count (SCC), i.e. assuming it is also relevant for SCC in MRF breed (despite no demonstrated in this breed compared to Lacaune for which is was done ) 36th ICAR Session, Niagara Falls, USA, 2008 8
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Milk composition and SCC recording (2/2)
Part-lactation sampling design available now for SCC in MRF breed since 2002
Are genetic parameters for milk traits and SCC (with such a simplified design) comparable in MRF breed and in Lacaune breed, i.e comparable in dairy sheep and dairy cattle ?
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First simplification: AC design for milk yield Lambing
Weaning
Suckling (or suckling plus milking)
Drying off
MILKING ONLY
MONTHLY RECORDING OF MILK YIELD
AC Method X X X X X Milk yield (recording of one of the 2 daily milkings, example morning) 36th ICAR Session, Niagara Falls, USA, 2008 10
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Part-lactation sampling design Milk composition and SCC : part-lactation sampling within AC method for milk yield
AC method : record of 1 of the 2 milkings
Parities 1
X
X
X
X
X
X
Milk yield Sampling for FC, PC & SCC
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Characteristics of the analysed MRF data Characteristics Breed Study period Animals in data (first lactation) Animals in pedigree
Manech red faced 2002-2007 58,378 118,313
Mean ± standard deviation of the traits Lactation number Length of milking period, d (after 30-d suckling period) Milk yield, litre Fat content, g/l (part lactation sampling) Protein content, g/l (part lactation sampling) Lactation SCS (LSCS) (part lactation sampling)
first lactation 132 d ± 42 149.2 l ± 63.1 61.1 g/l ± 8.8 47.8 g/l ± 3.9 3.36 ± 1.38
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Genetic parameters (Manech red faced breed) MY
FY
PY
FC
PC
LSCS
MILK yield
0,33
+0,87
+0,92
-0,39
-0,44
+0,21
FAT yield
+0,84
0,28
+0,91
+0,10
-0,16
+0,25
PROTEIN yield
+0,96 +0,82
0,30
-0,16
-0,06
+0,25
FAT content
-0,17
+0,34
-0,16
0,28
+0,60
+0,07
PROTEIN cont.
-0,34
-0,20
-0,04
+0,16
0,51
+0,07
LSCS
-0,26
-0,16
-0,17
+0,16
+0,38
0,10
Heritabilities on diagonal Genetic correlations above the diagonal Environmental correlations under
Genetic parameters 58,378 first lactations
between 2002 and 2007
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Genetic parameters : comparison Lacaune (121,283 first lactations) et MRF (58,378 first lactations) héritabilities
Genetic correlation with milk yield (MY)
Milk Yield
0,32 et 0,33
Fat content
0,41 et 0,28
- 0,43 et - 0,39
Protein content
0,51 et 0,51
- 0,48 et - 0,44
LSCS
0,15 et 0,10
0,15 et 0.21
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Conclusion (1/2)
Validation of the part-lactation sampling design for SCC in MRF breed as in Lacaune breed (comparable genetic parameters for milk traits and SCC)
Genetic relationship between udder health (SCC) and milk production traits is antagonistic in dairy sheep as in dairy cattle (udder health will be deteriorated when selecting only milk traits) 36th ICAR Session, Niagara Falls, USA, 2008 15
Conclusion (2/2)
the part-lactation sampling design is relevant both for milk composition and SCC selection in dairy sheep
such a very simplified design (a very few test days recorded per ewe) needs to maintain relevant accuracy for each individual test day as presently defined in ICAR requirements for recording devices and for analytical quality analysis of sheep milk. 36th ICAR Session, Niagara Falls, USA, 2008 16
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Thank you for your attention
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