MINISTRY OF EDUCATION
AND TRAINING
MINISTRY OF AGRICULTURE AND
RURAL DEVELOPMENT
NATIONAL INSTITUTE OF ANIMAL SCIENCES
PHAM VAN TIEM
EVALUATION AND SELECTION OF HOLSTEIN
FRIESIAN DAIRY BREEDING BULLS IN VIETNAM
Major: Animal production
Code No.: 62 62 01 05
SUMMARY OF THE PhD THESIS
HANOI - 2014
The thesis was completed at: National Institute of Animal
Sciences
Supervisors:
1. Associate Professor, Doctor Nguyen Van Duc
2. Doctor Le Van Thong
Opponent 1: ……………………………………..
Opponent 2 ………………………………………
Opponent 3: ………………………………………
The thesis is sumitted before the Thesis Examination Committee
(Institute Level) meeting at the National Institute of Animal Sciences at
[Time] [Date]
[Month]
[Year]
Thesis can be found at:
1. National Library
2. Library of National Institute of Animal Sciences
3. Library of Vietnam Ruminant Breeding Center
INTRODUCTION
1. RATIONALE
It is difficult to select dairy bulls because milk characteristics
are not manifestation. Therefore, several indirect methods have been
used for dairy bull selections. One of them, which has the highest
accuracy and effectiveness, is progeny testing. Progeny testing is
based on the pedigree, individual performance, and the lactation milk
yield of paternal half-sib sisters and daughters.
In Vietnam, cattle frozen semen has been produced and used
since 1970. After 45 years, most of bulls used for producing frozen
semen, are imported and mainly selected by their pedigree and
individual performance. Recently, some studies using progeny testing
for selection of Holstein Friesian (HF) dairy bulls have done in
Vietnam. However, there has been no study combined all 4 steps of the
progeny testing in a selection program. For the above reason, in order to
select the best Holstein Friesian breeding bulls for producing frozen
semen, contributing to faster, effectve and sustainable development in
Vietnam dairy sector, one study: "Evaluation and selection of Holstein
Friesian dairy breeding bulls in Vietnam" was undertaken
2. THE OBJECTIVES OF THE STUDY
To select the best HF bulls for dairy cattle breeding development
program in Vietnam via four steps of progeny testing.
To confirm the accuracy of dairy bull selection with 4 steps.
3. SCIENTIFIC AND PRACTICAL MEANINGS OF STUDY
3.1. The scientific meanings
Results of this thesis can be used as a sources of literature of
the progeny testing for HF dairy bulls with the highest of effectiveness
and accuracy though 4 steps: pedigree, individuals, and milk yield
potention EBV of bulls canculated from milk yield per lactation of
paternal half-sib sisters, and daughters.
1
This thesis also confirms that the progeny testing with 4 steps
can be applied succesfully in Vietnam conditions.
3.2. The practical meanings
Thesis is a scientific documentation, and could be used as a
materials for teaching, research at universities and institutes as well as
dairy farms. The methods and results in thesis can help to select the best
dairy bulls for suitable breeding programs aiming at improving milk
production in dairy cattle sector.
4. THE NEW CONTRIBUTiON OF THE THESIS
- The thesis is the first scientific work to sucessfully evaluate and
select Holstein Friesian dairy breeding bulls though 4 selection steps of
progeny testing: pedigree, individual, paternal half-sib sisters, and
daughters in Vietnam.
- Selection of dairy Holstein Friesian bulls for milk yield based
on EBV of the first lactation milk yield of paternal half-sib sisters and
daughters has a high accuracy.
- The results of the thesis demonstrate that the effectiveness for
each step of progeny testing for Holstein Friesian dairy bulls is different
and the effectiveness for selection is the highest when 4 steps of progeny
testing for Holstein Friesian dairy bulls fully implemented.
Chapter 1. LITERATURE REVIEW
1.1. PEDIGREE BASED SELECTION FOR DAIRY BULLS
Based on pedigree and phenotype values, as well as the bull
and cow genotype, good mothers and fathers were selected to mate
with each other in order to get young bulls of high-predicted genetic
merit for progeny testing.
1.2. INDIVIDUAL PERFORMANCE BASED SELECTION FOR
DAIRY BULLS
Growth and reproduction traits of HF bulls were used for
evaluating in order to select the good bulls for paternal half-sib sister
selection step.
2
1.3. SELECTION FOR DAIRY BULLS BY ESTIMATED BREEDING
VALUES CALCULATED FROM THE FIRST LACTATION MILK
YIELD OF THEIR SISTERS AND DAUGHTERS
HF bulls were selected by estimated breeding value of the first
lactation milk yield of paternal half-sib sisters and their daughters.
These two selection steps give high accuracy and efficiency because it
bases on the genetic merits of characteristic selection.
The selection for dairy bulls based on estimated breeding value
of the milk potential had done in a long time and obtained great values.
a. In the world
Zhang et al. (2000), reported that the estimated breeding values
(EBV) for milk yield per lactation of HF cows in China ranged from 1.160,29 to +2.052,75 kg of milk.
In addition, Powell et al. (2005) calculated the national EBV for
milk yield per lactation of 100 highest milk yield potential bulls from 10
countries and found out that on average, dairy bulls of Canada had the
highest EBV for this trait (+1785 kg of milk per lactation) and dairy bulls of
Australia had the lowest EBV for this trait (+745 kg of milk per lactation).
According to Gonzalez-Recio et al. (2005), for bull participating in the
international testing, average EBV for milk yield per lactation was +335 kg.
When using HF bulls from USA and from Ecuador for heifers
in Ecuador, Mashhadi et al. (2008) found out that if 10% of HF bulls
with the highest EBV was selected, EBV of USA HF bulls was +760
kg of milk/lactation and EBV of Ecuador HF bulls was +576 kg of
milk/lactation. EBVs of bulls in Iran for this trait ranged from -265 to
+1287 kg of milk/lactation
b. In Vietnam
Pham Van Gioi (2008) reported that the highest EBV for milk
yield per lactation was +1469.5 kg and the lowest EBV was 378.6 kg,
with reliability of 67-79%. Le Ba Que (2013), estimated that EBV of 9
imported HF bulls from United State and Cuba for the milk yield per the
first lactation varied from +36.62 to +1,064.58 kg.
3
According to Le Van Thong et al. (2013), using data from
daughters, EBV of 12 imported HF bulls from United State and Cuba for
the milk yield per the first lactation ranged from +53.15 to 1,232.8 kg.
Using data from parental haf-sib sisters, Le Van Thong et al.
(2014) also revealed EBV of 15 bulls born in Vietnam for the milk yield
per the first lactation ranged ranged from -899.1 to +666.0 kg of milk.
1.4. CURRENT SITUATION OF SELECTION FOR DAIRY BULLS
1.4.1. In the world
In Japan, dairy bulls have been selected by progeny testing with
four steps: 1) The creation of young bulls with a high-predicted genetic
merit for progeny testing (fathers and mothers of bulls selected for
annual mating; 2) Selection of potential young bulls from data of their
phenotype, growth rate and semen quality in individual testing; 3)
Creation of daughter herds from semen of selected bulls and 4)
Recording the milk yield per lactation of daughters and data analysis.
In Canada, every year, 400 dairy bull calves from nucleus dairy
herds have been chosen and transported to the stations for evaluation and
selection. In the stations, parameters utilized for evaluation and selection
included: growth rate; phenotype, resistance to disease; semen quality,
fertility and milk yield of paternal half-sib sisters and daughters.
1.4.2. In Vietnam
Recently, there have been several studies on selection of HF
dairy bulls by the progeny testing. However, no study has been
completed all 4 steps of the progeny testing.
For example, from data on growth rate and semen production
of young bulls, Le Van Thong et al. (2013) selected 20 elite bulls with
different ranks (10 HF bulls and 10 Brahman bulls). Nine HF bulls
were evaluated and selected from data on the milk production of
daughter herds (Le Ba Que, 2013).
In another study, Le Van Thong et al. (2014) selected HF
young bulls using data from pedigree, individual performance and also
growth rate of paternal half-sib sisters and daughters.
4
Chapter 2. MATERIALS AND METHODS
2.1. SUBJECTS, LOCATION AND TIME OF STUDY
2.1.1. The subjects of study
Thirty five male calves were born in nuclear herd, which satisfied
all standard points of selection for breeding. In which, 23 calves were born
in Moc Chau Farm (Son La) and 12 calves were born in Dairy Corporation
Pioneer (Tuyen Quang). After weaning, the best 15 calves, which have
good body condition, high growth rate, breeding soundness, mother milk
yield is higher 7,000 kg per lactation and father milk potential is above
12,000 kg of milk, were selected and raised at the Research and Frozen
semen production Moncada Station to evaluate and select for breeding.
2.1.2. Location and research conditions
- Bulls were raised and their semen was collected in Moncada Station
for Research and Frozen Semen Production (Tan Linh, Ba Vi, Ha Noi)
- 40 - 45 paternal half-sib sisterssisters with complete data of milk
yield per the first lactation/bull in Moc Chau and Duc Trong - Lam Dong
were used for analysis.
- 50 daughters of each bull in each locations were selected to
ensure that each bull had above 40 daughters, which finished their first
lactation. Thus, data on the milk yield per first lactation of 40 daughters of
each bulls were used for stasistical analysis
- Semen of young bulls was collected twice a week.
- Milk yield was recorded twice a day for whole lactation.
2.1.3. Time of study
Study was undertaken from January 2006 to December 2013.
2.2. SCOPE OF STUDY - CONTENTS
2.2.1. Pedigree based selection for Holstein Friesian bulls
- The identification of young bulls of high-predicted genetic
merits for progeny testing.
- The parental milk yield potential of father and mother of
breeding male calves.
- The effectiveness of pedigree based selection.
5
2.2.2. Individual performance based selection for Holstein Friesian bulls
- Growth rate of the bulls.
+ Body weight at birth, 6, 12, 18 and 24 months of age.
+ Cross body length, wither height, chest girth of HF young bulls.
- Some parameters of semen production of each young bulls:
semen volume (V), sperm motility (M), concentration (C), live sperm
rate, sperm grade (VMC - total number of forward movement/ejaculate,
post-thawing motility (Ap), number of straws produced per
standardized ejaculate.
- Effectiveness of individual performance based selection for Holstein
Friesian bulls.
2.2.3. Selection for Holstein Friesian bulls by EBV calculated
from the first lactation milk yield of their sisters
- Milk yield of 305 days lactation and standardized milk yield (
4% fat in milk) of the paternal half-sib sisters in the first lactation.
- Milk quality in the first lactation of the paternal half - sibs herd.
- Estimated breeding values of the first lactation milk yield of
their paternal half-sib sisters.
- Effectiveness of selection for Holstein Friesian bulls by EBV
of the first lactation milk yield of their sisters.
2.2.4. Selection for Holstein Friesian bulls by EBV calculated
from the first lactation milk yield of their daughters
- First lactation milk yield 305 days and standardized lactation
milk yield of their daughters.
- Milk quality of daughter herd in the first lactation.
- Estimated breeding values of the first lactation milk yield of
their daughters.
- Effectiveness of selection for Holstein Friesian bulls by
EBV of the first lactation milk yield of their daughters.
6
2.3. METHODS
2.3.1. Pedigree based selection for Holstein Friesian bulls
Pedigree based selection for male calves were mainly based on
the merit of parents. According to Vietnamese standad TCVN 3982-85:
mothers of male calves selected as potential bulls had to have: milk yield of
more than 7,000 kg/lactation; fat content in milk of eqivalent to or more than
3.5%; protein content in milk of eqivalent to or more than ≥3.0%; and fathers
of male calves selected as potential bulls had to have milk yield potential of
equavelent to or more than 12000 kg/lactation.
2.3.2. Individual performance based selection for Holstein Friesian bulls
2.3.2.1. Growth rate
- Body weight was measured at birth (kg) using 100 kg Nhon
Hoa scale (made in Vietnam); at 6, 12, 18 and 24 months of age using an
electric scale (Digi-Star US).
- Cross body length, wither height, chest girth of HF young bulls
were measured using the ruler (Digi-Star US) and tape of Vietnam.
- Growth rate, body weight of young bulls were evaluated
using Decision 1712/QD-BNN-CN (2008, Ministry of Agriculture and
Rural Development) as a standard.
2.3.2.2. Semen production
- Semen volume (V): was measured directly from collecting tube
and recorded in ml.
- Sperm motility (M) was measured using a microscope
(Milovanov).
- Sperm concentration (C): was measured using colorimetric
eqipment (Photomaster SDM5).
- Live sperm rate: was measured according to the Milovanov method.
-Sperm grade (VMC - total number of forward
movement/ejaculate) was calculated by multiplying V, A and C.
- Post-thawing motility (Ap %): 1-2 straws randomly taken for
each production day were put in 30oC water bath in 30 seconds then
check sperm motility using a microscope connecting with a computer.
7
-Number
of
straws
per
standardized
ejaculate
(straws/ejaculate) were recorded.
2.3.3. Selection for Holstein Friesian bulls by EBV
calculated from the first lactation milk yield of their sisters
2.3.3.1. First lactation milk yield 305 days and standard milk yield of sisters
- 305 day milk yields of the first lactation of paternal half-sib sisters
was measured by weighing twice per day, 1 day per month, and then
converted to 305 day milk yield of the first lactation (Matsumoto Shigeo,
1992).
- Standard milk yield was calculated by converting 305 day
milk yields 305 days to 4 % fat milk yiels using the equation (Nguyen
Hai Quan et al.,1995).
2.3.3.2. Milk quality in the first lactation of the paternal half - sibs herd
Milk fat and protein were analyzed by LCUMA equipment
(LactiCheck Ultrasonic Milk Analyzer).
2.3.3.3. Estimated breeding values of milk potential calculated from
the first lactation milk yield of the paternal half-sib sisters
EBVs of milk potential of each HF bull were calculated from the
paternal half-sib sister milk yield using the index selection method.
2.3.4. Selection for Holstein Friesian bulls by EBV calculated
from the first lactation milk yield of their sisters
2.3.4.1. First lactation 305 day milk yield and standard milk yield of
their daughters
Measurements were similar to these of sisters.
2.3.4.2. Milk quality of daughter herd in the first lactation
Measurements were similar to these of sisters2.3.4.3.
Estimated breeding values of milk potential calculated from the first
lactation of their daughters
Measurements were similar to these of sisters
2.4. DATA ANALYSIS
- Before statistical analysis, data expressed in a form of
percentage were changed to another form using the following equation:
8
Y = Degrees {asin[sqrt(x/100)]}.
After statistical analysis, these data back were changed to the
orignal form: Y 1 = 100 x {Sin[radians(x)]} 2 .
- The least-squares mean and standard errors were determined using
Proc GLM, SAS 9.1.
- Estimation of variance components was done using VCE6
- Estimation of parameters in equations to calculate EBV of each
bull were done using the ZPLAN+ program (Florence Ytournel. 2011).
Chapter 3. RESULTS AND DISCUSSION
3.1. PEDIGREE BASED SECECTION FOR HOLSTEIN FRIESIAN BULLS
3.1.1. Identification of young bulls of high-predicted genetic merit
for individual testing
15 male calves of 35 HF male calves meeting all requirement for
a progeny testing study were selected (10 male calves born in Moc Chau,
accounting for 66.66% and other 5 born in Tuyen Quang, accounting for
33.33%). The remarkable feature of all calves selected was black and
white and their average birth weight was 40.27 kg.
3.1.2. Parental milk yield potential of father and mother of male
calves selected
Table 3.2. Father milk potential and mother milk yield
Father milk yield
Mother milk yield
Bull ID
potential
Kg/lactation Fat (%)
Protein (%)
(kg/lactation)
290
12,245
7,025
3.50
3.00
291
12,245
7,265
3.65
3.35
292
12,868
7,500
3.60
3.30
293
12,473
7,350
3.60
3.32
294
12,868
7,450
3.54
3.15
295
12,473
7,600
3.50
3.20
296
12,473
7,800
3.50
3.20
297
15,460
8,582
3.60
3.22
9
Bull ID
298
299
2100
2101
2102
2103
2104
Average
Father milk yield
potential
(kg/lactation)
15,460
15,460
12,473
12,473
12,245
12,245
12,245
13,047.07
Mother milk yield
Kg/lactation
Fat (%)
Protein (%)
8,786
7,025
7,036
7,045
7,085
7,050
7,125
7,448.27
3.50
3.55
3.50
3.62
3.52
3.55
3.50
3.55
3.20
3.25
3.25
3.30
3.20
3.20
3.25
3.23
All fifteen HF bulls selected were born in Vietnam. Their
fathers from United State had a high milk yield potential, and their
mothers from a nuclear herd in Moc Chau and Lam Dong Farms.
3.1.3. Effectiveness of HF male calves via pedigree selection
15 male calves were selected from 35 HF male calves, meeting
requirements for progeny testing. Selected calves were better in
conformation, growth rate, and reproductive soundness. The average
milk yield potential of selected calves were 10,247.67 kg/lactation and
79.17 kg (equivalent 0.78%) higher than milk yield potential of 35 HF.
3.2. INDIVIDUAL PERFORMANCE BASED SECECTION FOR
HOLSTEIN FRIESIAN BULLS
3.2.1. Growth rate of the HF bull
3.2.1.1. Body weight
Average body weight of HF male calves at birth, 6, 12, 18 and 24
months of age were 40.27; 192.60; 287.27; 400.13 và 495.67 kg, respectively.
According to Decision 1712/QĐ-BNN-CN (Ministry of Agriculture and
Rural Development, 2008), body weight of breeding bull had to be 35-45 kg
(at birth), 140-160 kg (6 months), 230-270 kg (12 months), 400-450 kg (24
months). Thus, 3 bulls (ID: 290, 299 and 2100), did not meet the standard
weight at 24 month in Decision 1712/QĐ-BNN-CN .
10
Table 3.4. Body weight of HF calves (kg)
6
12
18
Calves ID
At birth
months months months
290
38
145
238
302
291
41
209
302
430
292
40
208
304
443
293
40
205
300
446
294
39
203
295
407
295
41
208
308
448
296
41
206
305
439
297
42
207
307
432
298
40
207
300
440
299
39
158
247
300
2100
40
160
241
285
2101
39
185
300
385
2102
42
203
285
435
2103
40
190
290
415
2104
42
195
287
395
Average
40.27
192.60 287.27 400.13
24
months
365
540
541
519
518
532
540
541
540
370
350
495
545
527
512
495.67
3.2.1.2. Cross body length, wither height, chest girth of HF young bulls
Average wither height at 12 and 24 month old of HF young bulls was
125.12cm and 143.93cm,respectively. Cross body length at 12 and 24
month old was 135,80cm and 156,07cm, respectively. Chest girth at 12
and 24 month old was 154.53 cm and 189.20, respectively. After
evaluation, 03 HF bulls (ID: 290, 299 and 2100) were eliminated and 12
HF bulls were kept for evaluation of their frozen semen production.
3.2.2. Semen production
3.2.2.1. Semen volume
Semen volume (V) per ejaculate of each bull in this study was
different. The highest V was found in bull with ID number 292 (7.02
ml/ejaculate) and the lowest was found in bull with ID number 2101
(3.64ml/ejaculate).
11
Table 3.6. Semen volume of HF bull (ml/ejaculate)
V meeting standards for
V
production
Bull ID
n
Mean
SE
n
Mean
SE
bc
ab
291
100 6.20
0.22
84
6.92
0.18
292
100
7.02a
0.14
98
7.11a
0.13
bc
cd
293
100 6.35
0.14
96
6.40
0.13
294
100
5.57d
0.18
88
5.98 d
0.15
bc
cd
295
100 6.43
0.12
100
6.43
0.12
c
d
296
100
6.09
0.13
100
6.09
0.13
297
100 6.67ab
0.16
100
6.67 be
0.16
bc
cd
298
100 6.38
0.14
100
6.38
0.14
e
e
2101
100
3.64
0.16
56
4.72
0.17
2102
100 5.98cd
0.15
98
6.05 d
0.14
c
cd
2103
100
6.15
0.13
98
6.23
0.12
cd
d
2104
100 5.94
0.17
96
6.10
0.15
Average
1200 6.03
0.05
1114
6.31
0.04
Means in the same colum with different superscripts were statistically
significantly different (P<0.05).
3.2.2.2. Sperm motility
Average sperm motility of these HF bulls in this study was
65.19%. The highest sperm motility was found in bull with ID number
198 (68.75%) and the lowest sperm motility was founs in bull with ID
number 294 (54.10%).
The difference in average sperm motility between these HF
bulls was statistically significant (P<0.05).
Table 3.7. Sperm motility of HF bull (%)
A meeting standards for
Sperm motility (A)
production
Bull ID
n
Mean
SE
N
Mean
SE
291
100
65.55 cde 0.71 50
71.50 ab
0.33
292
100
68.70 a
0.77 80
72.00 a
0.28
e
a
293
100
64.30
0.86 37
72.03
0.41
294
100
54.10 g
1.15 18
70.56 c
0.38
12
Bull ID
295
296
297
298
2101
2102
2103
2104
Average
Sperm motility (A)
n
100
100
100
100
100
100
100
100
1200
Mean
68.30 ab
67.90 abc
67.50 abcd
68.75 a
60.95 f
65.85 bcde
65.25 de
65.12 de
65.19
SE
0.63
0.79
0.80
0.55
1.00
0.76
0.81
1.02
0.27
A meeting standards for
production
N
Mean
SE
c
79
70.57
0.18
82
71.22 abc
0.24
bc
82
70.67
0.19
83
70.84 bc
0.21
c
40
70.38
0.21
c
65
70.46
0.18
60
71.00 bc
0.26
a
55
71.91
0.33
731
71.09
0.08
Means in the same colum with different superscripts were statistically
significantly different (P<0.05).
3.2.2.3. Sperm concentration
Table 3.8. Sperm concentration of HF bull (billion/ml)
C meeting standards for
C
production
Bull ID
n
Mean
SE
n
Mean
SE
a
a
291
100
1.23
0.02
94
1.26
0.02
292
100
1.12 b
0.02
88
1.19 bc
0.02
bcd
de
293
100
1.05
0.02
83
1.13
0.02
e
f
294
100
0.94
0.03
70
1.05
0.03
295
100
1.10 bc
0.02
93
1.13 de
0.02
de
f
296
100
1.00
0.02
89
1.04
0.02
a
a
297
100
1.20
0.02
94
1.25
0.02
298
100
1.06 bcd
0.02
89
1.11 de
0.02
de
ef
2101
100
0.99
0.03
80
1.08
0.02
cd
cd
2102
100
1.04
0.02
77
1.14
0.01
2103
100
0.95 e
0.02
70
1.04 f
0.01
cd
ab
2104
100
1.04
0.03
67
1.23
0.02
Average
1200
1.06
0.01
994
1.14
0.01
Means in the same colum with different superscripts were statistically
significantly different (P<0.05).
13
Average of sperm concentration in each ejaculate of HF bulls
in this study was 1.06 billion/ml. The highest value of sperm
concentration was observed in bull with ID number 299 (1.23
billion/ml) and the lowest value of sperm concentration was observed
in bull with ID number 294 (0.94 billion/ml).
The difference of average sperm concentration between these
bulls in this study was statistically significant (P<0.05).
3.2.2.4. Live sperm percentage
Results showed that average live sperm percentage was 79.15%.
The highest value of live sperm percentage was 81.03% and lowest live
sperm percentage was 76.03%. Means of live sperm percentage average
between these bulls were significantly different (P<0.05).
3.2.2.5. Sperm grade (VMC - total number of forward
movement/ejaculate)
Total number of forward movement/ejaculate of HF bull born
in Vietnam was 4.24 billion/ejaculate. The highest VMC was found in
bull with ID number 292 (5.40 billion) and the lowest VMC was found
in bull with IDnumber 2101 (2.24 billion). The different of those value
in all dairy bull were significantly (P<0.05).
Table 3.10. Total number of forward movement/ejaculate - VMC
(billion/ time)
VMC
Bull ID
291
292
293
294
295
296
297
298
2101
n
100
100
100
100
100
100
100
100
100
Mean
5.23 ab
5.40 a
4.44 cd
2.76 f
4.83 bc
4.11 de
5.35 a
4.63 c
2.24 g
SE
0.25
0.16
0.18
0.13
0.14
0.12
0.15
0.16
0.12
14
VAC meeting standards for
production
N
Mean
SE
43
7.12 a
0.21
77
6.00 b
0.12
b
37
5.67
0.26
15
3.58 f
0.31
cd
78
5.11
0.15
e
82
4.44
0.11
80
5.57 bc
0.14
de
77
4.91
0.13
26
2.95 g
0.18
VMC
Bull ID
2102
2103
2104
Average
n
100
100
100
1200
Mean
4.07 de
3.81 e
4.00 de
4.24
SE
0.14
0.12
0.17
0.05
VAC meeting standards for
production
N
Mean
SE
de
47
4.59
0.17
42
4.45 e
0.15
de
42
4.92
0.20
646
5.11
0.06
Means in the same colum with different superscripts were statistically
significantly different (P<0.05).
3.2.2.6. Post – thawing motility
Average post – thawing motility of these HF bulls in this study was
40.04%. Although there was a difference among individuals, these
difference were not statistically significant (P>0.05).
Table 3.11. Post - thawing motility (%)
Post –thawing motility
Post - thawing motility
meeting standards for
Bull ID
production
n
Mean
SE
n
Mean
SE
291
43
40.23
0.76
31
42.90 a
0.45
292
77
40.32
0.41
68
41.25 b
0.30
b
293
37
40.27
0.43
33
40.91
0.34
294
15
39.00
1.21
11
41.36 b
0.70
295
78
39.62
0.57
56
42.05 ab
0.46
296
82
40.06
0.35
74
40.81 b
0.26
ab
297
80
40.63
0.47
67
42.01
0.35
298
77
40.19
0.48
65
41.54 ab
0.36
b
2101
26
39.23
0.82
19
41.32
0.52
ab
2102
47
39.79
0.66
38
41.58
0.43
2103
42
39.64
0.65
34
41.32 b
0.38
ab
2104
42
40.00
0.74
32
42.19
0.50
Average
646
40.04
0.16
528
41.57
0.12
Means in the same colum with different superscripts were statistically
significantly different (P<0.05).
15
Post – thawing motility meeting production standards of these HF
bulls in this study was 41.57%. The difference among individual bulls was
statistically significant (P <0.05).
3.2.2.7. Numbers of straws produced per a standardized ejaculate of
each bull
After evaluating semen quality, two HF bulls (ID number: 294
and 2101) were eliminated from total 10 bulls. This was because both of
them had a low semen quality, percentage of standardized ejaculate
ranged from 11% to 19%, equalled to from 1,918 to 2,544
straws/head/year. The rest bulls could produce more 7,000
straws/head/year.
Thus, two bulls (294 and 2101) showed poor quality (produced
less than 7,000 straws/year), did not meet the standards for frozen semen
production.
Table 3.12. Numbers of straws produced per standardized ejaculate
Numbers of straws produced /a standardized
ejaculate
Bull ID
n
Mean
SE
a
291
31
329.42
7.92
292
68
273.41b
3.88
abs
293
33
256.21
7.72
f
294
11
174.27
8.05
295
56
236.20cd
5.34
e
296
74
204.59
4.38
bcd
297
67
251.52
4.64
298
65
228.14cde
5.70
g
2101
19
133.89
5.61
2102
38
203.50e
4.62
e
2103
34
207.24
4.86
ed
2104
32
223.47
4.57
Average
528
234.28
2.86
Means in the same colum with different superscripts were statistically
significantly different (P<0.05).
16
3.2.3. Effectiveness of individual performance based selection for
dairy HF bulls
Individual performance based selection was mainly focused on
growth rate and frozen semen production. From this selection, 10 HF
bulls, who met the standard of breed, their average milk yield potential
was 10,316.50 kg/lactation, were selected. The average milk yield
potential of 10 HF bulls was 68.83 kg/lactation higher (or increased by
0.67%) than that of 15 HF bulls selected using pedigree based
selection. Therefore, these 10 bulls were continously selected by their
sisters.
3.3. SELECTION FOR HOLSTEIN FRIESIAN BULLS BY MILK
YIELD POTENTIAL EBV CALCULATED FROM FIRST
LACTATION MILK YIELD OF THEIR SISTERS
3.3.1. 305 day milk yield and 4 % fat milk yield of sisters in the
first lactation
On average, 305 day milk yield/first lactation of paternal halfsib sisters of 10 HF bulls was 4,915.50 kg/lactation. However, 4 % fat
milk yield of paternal half-sib sisters of 10 HF bulls was only 4,603.10
kg/lactation.
The difference between 305 day milk yield/first lactation of
paternal half-sib sisters and 4 % fat milk yield of paternal half-sib
sisters of 10 HF bulls was statistically significant (p<0.05). However,
differences in
305 day milk yield/first lactation of paternal half-sib sisters of
bulls: 291, 2102, 2103 and 2104 was significantly different from that
of the rest bulls (p>0.05). However, 305 day milk yield/first lactation
of paternal half-sib sisters of bulls: 292, 203, 295, 296, 297 and 298,
was not significantly different (p>0.05).
17
Table 3.12. 305 days milk yield/first lactation and 4 % fat milk
yield of the paternal half –sib sisters
Milk yield of paternal half –sib sisters
in the first
Number
lactation milk yield (kg/305 day)
Mother's
Father's bull ID
of paternal
bull ID
305 milk
4 % fat milk
half -sibs
yield/lactation
yield
Mean
SE
Mean
SE
RUANN CELSIUS 291, 2102,
160
4,516.13a 50.91 4,261.53a 46.60
MOTTO-2087-ET 2103, 2104
RUANN VINCER
NOMAD 2728-ET
COOKS VALLEY
AMEL BUCK- ET
RALMA TERRY
FLEET-ET
Average
292
45
5,198.20b 96.00 4,879.74b 87.87
293, 295,
296
135
5,091.86b 55.43 4,754.32b 50.73
297, 298
80
5,257.60b 72.00 4,875.39b 65.90
420
4,915.50 35.00 4,603.10 31.60
Means in the same colum with different superscripts were statistically
significantly different (P<0.05).
3.3.2. Milk quality in the first lactation of the paternal half - sibs herd
Results showed that average milk fat percentage in the first
lactation of paternal half-sib sisters of these HF bulls was 3.58%, the
highest value was 3.63% and the lowest was 3.53%. Differences in average
milk fat percentage of paternal half-sibs herds were significant (P<0.05).
Average protein percentage in the first lactation of all paternal
half-sib sisters was 3.29%; the highest protein percentage was 3.33% and
the lowest protein percentage was 3.23%. Differences between these
values were significant (P<0.05).
3.3.3. Estimated breeding values of milk yield potential of HF bulls calculated
from the first lactation milk yield of the paternal half-sib sisters
EBV of milk yield potential of 10 HF bulls calculated from the
first lactation milk yield of paternal half-sib sisters was widely
18
fluctuated and ranged from -384.78 kg and +319.22 kg/lactation. Among 10
HF bulls, 6 had positive EBV from +169.50 to +319.22 kg/lactation. The rest 4
HF bulls had negative EBV (-384.78 kg/lactation).
Table 3.10. EBV of milk yield potential of 10 HF bulls calculated
from the first lactation milk yield of paternal half-sib sisters
305 day
EBVs of milk yield
milk
potential
Bull Number yield/ of
Father's bull ID
ID
of sisters paternal
reliabili
EBV
Rank
half-sib
ty (%)
sisters
297
5,257.60 +319.22 48.26
1
RALMA TERRY
80
FLEET-ET
298
5,257.60 +319.22 48.26
1
RUANN VINCER
NOMAD 2728-ET
292
45
5,198.20
2
5,091.86 +169.50 48.95
3
135
5,091.86 +169.50 48.95
3
5,091.86 +169.50 48.95
3
4,516.13 -384.78 49.11
4
RUANN
4,516.13 -384.78 49.11
4
CELSIUS
160
4,516.13 -384.78 49.11
4
MOTTO-2087-ET
4,516.13 -384.78 49.11
4
3.3.4. Effectiveness of bull selection using EBV of milk yield potential
of HF bulls calculated from the first lactation milk yield of paternal
half-sib sisters
On average, milk yield potential of 6 HF bulls selected using EBV of
milk yield potential of HF bulls calculated from the first lactation milk
yield of paternal half-sib sisters was 10,735.42 kg/lactation. This figure
was 487,75 kg/lactation higher than that of 15 HF bulls selected by
pedigree, and 4.06% higher the that of 10 HF bulls selected using
individual performance. As a result, 6 HF bulls, which had a positive
EBV, were selected for futher evaluation in a next step.
COOKS VALLEY
AMEL BUCK- ET
293
295
296
291
2102
2103
2104
+250.58 47.03
19
3.4. SELECTION FOR HOLSTEIN FRIESIAN BULLS BY MILK
YIELD POTENTIAL EBV CALCULATED FROM FIRST
LACTATION MILK YIELD OF THEIR DAUGHTERS
3.4.1. 305 day milk yield per first lactation and 4 % fat milk yield of
their daughters
The results presented showed that 350 day milk yield of the first
lactation of 6 HF bull daughters were 5,474.90 kg/lactation.
Table 3.11. 305 day milk yield per first lactation and 4 % fat milk
yield of their daughters
Milk yield per first lactation of daughters (kg/305
Number
days)
Bull ID
of
305 day milk yield
4 % fat milk yield
daughters
Mean
SE
Mean
SE
292
293
295
296
45
5,524.79ab
72.14
5,193.47
68.82
42
b
94.80
4,985.17
92.87
ab
112.56
5,052.47
104.58
ab
92.95
5,063.83
88.69
ab
104.93
5,213.65
101.62
40
43
5,315.56
5,353.84
5,414.67
297
42
298
44
5,635.53a
100.28
5,239.53
92.07
256
5,474.90
39.70
5,126.70
37.50
Average
5,589.61
Where: a,b means in the same colum with different superscripts was
statistically significantly different (P<0.05).
3.4.2. Milk quality of daughter herd in the first lactation
Results showed that the average milk fat percentage on first
lactation of daughter herds were 3.5%. There were significant
differences between average milk fat of daughter herds of HF bulls
(p<0.05). Average milk protein percentage on first lactation of daughter
herds were 3.27%. The differences between average milk protein of
daughter herds of HF bulls were also statistically significant (P<0.05).
20
3.4.3. Estimated breeding values of milk yield potential of HF bulls
calculated from the first lactation milk yield of their daughters
EBV of milk yield potential of HF bulls calculated from the
first lactation milk yield of their daughters was rather high, positive and
ranged from +285.29 to +851.54 kg/first lactation. The reliability of HF
bulls’ EBV varied between 93,39 and 94,06%.
Table 3.13. EBV of milk yield potential of HF bulls calculated
from the first lactation milk yield of their daughters
Daughters’
EBV of milk yield potential
Number
milk yield in
Bull ID
of
reliability
the first
EBV
Rank
daughter
(%)
lactation
298
44
5,635.46
+851.54
93.94
1
297
42
5,589.59
+766.29
93.68
2
292
45
5,524.74
+657.83
94.06
3
296
43
5,414.67
+460.59
93.81
4
295
40
5,353.84
+350.36
93.39
5
293
42
5,315.54
+285.29
93.68
6
3.4.4. Effectiveness of bull selection using EBV of milk yield
potential of HF bulls calculated from the first lactation milk yield
of their daughters
On average, milk yield potential of 3 HF bulls selected using EBV of
milk yield potential of HF bulls calculated from the first lactation milk
yield of their daughters was 11,442.67 kg/lactation, increased by
12.53, 11.66, 10.92, and 6.59% in comparision with that of 35 HF
bulls at the preselection and at pedigree, individuals, and parental half–
sib sisters selection, respectively.
The accuracy of milk yield potential EBV of HF bulls
calculated from the first lactation milk yield of their daughters was
high, and varied from 93.39% and 94.06%.
21
Table 3.14. Milk yield potential of Holstein Friesian bulls in 4 selection
steps and effectiveness for each step
Milk yield potential of each steps (kg/lactation)
Comparison (%)
Selection Selection Selection
Items
Pre-
Pedigree Individual
selection selection selection
Selection Selection based on based on based on
based on based on daughter/ daughter/ daughter/
sisters daughter
Pre-
Pedigree Individual
selection selection selection
Number of
bulls
35
15
10
6
3
8.57
Father milk
potential 13,023,43 13,047.07 13,018.70 13,354.5014,596.00 112.07
(kg/lactation)
Mother milk
yield
7,313.57 7,448.27 7,614.30 7,936.33 8,289.33 113.34
(kg/lactation)
Bull milk
potential 10,168.50 10,247.67 10,316.50 10,735.4211.442.67 112.53
(kg/lactation)
20.00
Selection
based on
daughter/
Selection
based on
sisters
30.00
50.00
111.87 112.12
107.84
111.29 108.87
104.45
111.66 110.92
106.59
CONCLUSIONS AND RECOMENDATIONS
1. CONCLUSIONS
Fifteen HF bulls were selected from 35 HF bulls by preselection. The average milk yield potential of 15 selected HF bulls was
79.17 kg/lactation (or 0.78%) higher than that of 35 HF bulls in the
pre- selection.
Ten HF bulls were selected by individual performance based
selection (mainly growth rate and semen quality) from 15 HF bulls
selected by pedigree based selection. The milk yield potential of
22
selected bulls by individual performance based selection was 0.67%
higher than that of average milk potential of the herd.
Using EBV of milk yield potential of HF bulls calculated from
the first lactation milk yield of their paternal half-sib sisters, the best 6
bulls were selected, accounted for 40% of bull herds selected by
pedigree based selection and 60% of bull herd selected by individual
performance based selection. Six selected bulls had a positive EBV of
milk yield potential calculated from milk yield of their paternal halfsib sisters. EBV values varied between +169.50 and 319.22
kg/lactation. Because of the reliability of EBV of milk yield potential
of HF bulls calculated from the first lactation milk yield of their
paternal half-sib sisters was low (47.03 - 49.11%), the accuracy of this
step was limited. However, this selection step allowed to select HF
bulls, who had a high milk yield potential.
Three best bulls of six bulls (50%) were selected from 6 HF
bulls were selected using EBV of milk yield potential of HF bulls
calculated from the first lactation milk yield of their daughters. These
bulls had a higher EBV varying from +657.83 and +851.54 kg of milk
per lactation, and reliability of EBV was high and reanged from
93.94% to 94.06%. Selection using EBV of milk yield potential of HF
bulls calculated from the first lactation milk yield of their daughters.
increased milk yield potential by 11.66%, 10.92% and 6.59%
compared to pedigree, individual performance based selection and
selection using EBV calculated from the first lactation milk yield of
their paternal half-sib sisters, respectively. Moreover, the reliability of
milk yield potential EBV of bulls calculated from the first lactation
milk yield of their daughters were higher than the reliability of milk
yield potential EBV of bulls calculated from the first lactation milk
yield of their paternal half-sibs: 93.39 - 94.06% vs. 47.03 - 49.11%.
23
Thus, the selection of bulls using milk potential EBV calculated from
the first lactation milk yield was given an accurater results.
Thus, HF bull selection through 4 steps, including pedigree,
individual performance selection, using EBV of milk yield potential
calculated from milk yield per lactation of their paternal half-sib
sisters and using EBV of milk yield potential calculated from milk
yield per lactation of their daughters was the best method for selecting
the best bulls with the highest milk potential, which would contribute
to enhance milk production of HF dairy cows and economic efficiency
of dairy sector in Vietnam.
2. RECOMENDATIONS
HF bull selection through 4 steps should be applied frequently,
continuously in order to select the best HF bulls for frozen semen
production and for improvement of productivity and higher economic
efficiency of dairy sector.
Maximum utilization of genetic resources of selected bulls
will contribute to improving the milk yield and economic efficiency of
the dairy sector in Vietnam.
24