1Sameh Abdel-Salam, ICAR 2010
GENETIC GAIN IN OPEN NUCLEUS BREEDING SCHEME TO IMPROVE MILK TO IMPROVE MILK PRODUCTION IN EGYPTIAN BUFFALOS.A. Abdel-SalamFaculty of Agriculture, Cairo University, Egypt3/6/2010
INTRODUCTIONINTRODUCTION2
FAOSTAT (2009) the Egyptian buffalo contributes about
2.7% and 8.4% to the world buffalo's milk and meat.2.7% and 8.4% to the world buffalo s milk and meat.
The proportion of Egyptian buffaloes to the world
buffalo’s milk production decreases year after year.
The increase of total milk production of Egyptian
buffaloes was due only to increasing buffalobu a oes as ue o y o c eas g bu a o
population size.
3/6/2010Sameh Abdel-Salam, ICAR 2010
INTRODUCTIONINTRODUCTION3
Livestock production in developing regions is
generally characterized by small herd sizegenerally characterized by small herd-size,
uncontrolled mating, and the absence of pedigreeg p g
and performance recording.
These characteristics limit the implementation of
effective genetic improvement programs.
3/6/2010Sameh Abdel-Salam, ICAR 2010
INTRODUCTIONINTRODUCTION4
To overcome these problems, nucleus breeding
schemes have been suggested in which geneticschemes have been suggested, in which genetic
improvement is centrally organized in a population
maintained in research institutes or government farms.
The open nucleus breeding scheme offers a simpler
procedure for producing and disseminating breedingprocedure for producing and disseminating breeding
stock of known value.
3/6/2010Sameh Abdel-Salam, ICAR 2010
INTRODUCTIONINTRODUCTION5
The establishment of two-tier open nucleus breeding
system to maximize genetic improvement, reduce
inbreeding rate and reduce the total cost of recording
in smallholder systemin smallholder system.
Several of studies indicated the significance of using
open nucleus breeding scheme to improve milk
production of buffalo and increase the rate of geneticproduction of buffalo and increase the rate of genetic
gain.
3/6/2010Sameh Abdel-Salam, ICAR 2010
INTRODUCTIONINTRODUCTION6
The purpose of this paper was to use the simulation
t h i t t d th t d ti i btechnique to study the expected genetic gain by
changing migration rates and male selectiong g g
intensity in four generations of applying two-tier
open nucleus breeding scheme to improve milk
production of Egyptian buffaloes using different
l d l ti inucleus and population sizes.3/6/2010Sameh Abdel-Salam, ICAR 2010
Basic parametersBasic parameters
The estimates used in generating the simulated populations8
The estimates used in generating the simulated populations
Parameter Estimate Reference
Average total milk yield (TMY) 1884, kg CISE, 2007
Phenotypic variance for TMY 191845, kg2 CISE, 2007
Phenotypic standard deviation for TMY 438, kg CISE, 2007Phenotypic standard deviation for TMY 438, kg CISE, 2007
Average generation interval 5.78, yr Mourad, 1990
Heritability estimate 0.17 CISE, 2007
CISE: Cattle Information Systems/Egypt3/6/2010Sameh Abdel-Salam, ICAR 2010
Calculation of the expected genetic gain in ilk i ldmilk yield
I t i bl f l l ti ti i 9
Input variables for calculating genetic gain Item Description Symbol Value
H i bili i h2 0 17Heritability estimate h2 0.17Replacement rate r 0.20Fraction of total population in nucleus p 0.05, 0.10Fraction of nucleus dams born in base x 0 50Fraction of nucleus dams born in base x 0.50Fraction of base dams born in nucleus y 0.08, 0.14, 0.17
Fraction of nucleus sires born in base v 0.00
F ti f b i b i l 0 10 0 20 0 30 0 60 1 00Fraction of base sires born in nucleus w 0.10, 0.20, 0.30, 0.60, 1.00
Proportion of all males born used as sires a 0.05, 0.10, 0.20
Proportion of all females born used as dams b 0.80Si l d l i i ( b f b d bl f l ) 2 Simulated population size (number of breedable females) z 10000, 25000, 50000, 100000Generations G 1, 2, 3, 4
3/6/2010Sameh Abdel-Salam, ICAR 2010
S f b di h d Structure of breeding scheme and gene migration
10g
3/6/2010Sameh Abdel-Salam, ICAR 2010
The effects of the different variables on genetic gain were analyzed according to the following model:
GGijklmnop=µ+Gi+zj+pk+al+MRm+wn+yo+eijklmnopijklmnop µ i j pk l m n yo ijklmnop
where GG is the genetic gain of milk yield, µ is the average genetic gain of milk yield, Gi is the number of average genetic gain of milk yield, Gi is the number of generation (4 level), zj is the population size (4 level), pk is the fraction of total population in nucleus (2 pk is the fraction of total population in nucleus (2 levels), al is the proportion of all males born used as sires (3 levels), MR is the mating ratio (6 levels), wsires (3 levels), MRm is the mating ratio (6 levels), wnis the fraction of base sires born in nucleus (5 levels), y is the fraction of base dams born in nucleus (3 yo is the fraction of base dams born in nucleus (3 levels) and eijklmnop is the residual term.
3/6/201011
Sameh Abdel-Salam, ICAR 2010
cd
b
a
a,b,c,dMeans with different letters differ significantly (P<0.05).13
Change of genetic gain means by generation number.
3/6/2010Sameh Abdel-Salam, ICAR 2010
450
n, k
g
d
410
430
etic
Gai
n
b
c
d
390n
of G
ene
a
350
370
Mea
n
10000 25000 50000 100000
Population Size (z)
a,b,c,dMeans with different letters differ significantly (P<0.05).14
Change of genetic gain means by changing population size (z).
3/6/2010Sameh Abdel-Salam, ICAR 2010
Least squares mean and standard errors (SE) of genetic gain ofilk i ld (k ) i i l d b ff l l i f diffmilk yield (kg) in simulated buffalo populations of different
nucleus sizes (p)
p Mean SE
0.05 397a 70.10 415b 6
a,bMeans with different letters differ significantly (P<0.05)15
3/6/2010Sameh Abdel-Salam, ICAR 2010
405
406
, kg
a
404
405
etic
Gai
n
a
402
403of
Gen
ea
400
401
Mea
n
4000.05 0.10 0.20
Proportion of all males born used as sires (a)
aMeans with same letters do not differ significantly (P>0.05).
p ( )
16
Change of genetic gain means by changing proportion of all males born used as sires (a).
3/6/2010Sameh Abdel-Salam, ICAR 2010
500
400
450
Gai
n, k
g d
350
400
Gen
etic
Gab
bc
250
300
Mea
n of
G aab
2500.1 0.2 0.3 0.6 1.0
Fraction of base sires born in nucleus (w)
M
a,b,c,dMeans with different letters differ significantly (P<0.05).
Fraction of base sires born in nucleus (w)
17
Change of genetic gain means by changing fraction of base sires born in nucleus (w).
3/6/2010Sameh Abdel-Salam, ICAR 2010
500
kg
d d d
400
450
tic G
ain,
k
c
350
400
of G
enet
b
250
300
Mea
n a
2501:25 1:50 1:100 1:1000 1:2500 1:5000
Mating ratio (male: female)
a,b,c,dMeans with different letters differ significantly (P<0.05).
g ( )
18
Change of genetic gain means by changing different mating ratios (MR).
3/6/2010Sameh Abdel-Salam, ICAR 2010
450
n, k
g
430
440
etic
Gai
n b
410
420n
of G
ene
aa
390
400
Mea
n a
3900.08 0.14 0.17
Fraction of base dams born in nucleus (y)
a,bMeans with different letters differ significantly (P<0.05).19
Change of genetic gain means by changing fraction of base dams born in nucleus (y).
3/6/2010Sameh Abdel-Salam, ICAR 2010
CONCLUSIONCONCLUSION20
The open nucleus breeding scheme offers a suitable
practical procedure for producing and disseminating practical procedure for producing and disseminating
buffalo bulls of known breeding values.
Applying ONBS for many generations of selection
could accelerate the rate of genetic gain of milk
d ti i b ff l d i th ilk production in buffalo and increase the average milk
yield by 15% in G1 to 26% in G4. y y
3/6/2010Sameh Abdel-Salam, ICAR 2010
CONCLUSIONCONCLUSION21
It is recommended to take into account mating
ti h l i ONBS ith th bi ti ratios when applying ONBS with the combinations
of z (population size) and p (nucleus size) which (p p ) p ( )
affect a (proportion of all males born used as sires)
and w (fraction of base sires born in nucleus).
3/6/2010Sameh Abdel-Salam, ICAR 2010
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