Asi 510
Asi 510
1a. a producer is selecting for improved weaning weight by using phenotypic selection in beef
cattle. Assume heritability of weaning weight is 0.30, current herd average is 400 lbs, and
phenotypic standard deviation is 40 lbs. He saves 5% of males and 30% of females. The average
age of males when offspring are born is 3yrs and the average age of females when offspring are
born is 6 yrs. What response per year will he achieve with this selection program? (hint: the
overall selection intensity and generation interval are the simple average of male and female
selection intensity or generation interval)
B. This producer decides to use EPD calculated by national cattle evaluation instead of
pheynotypes in his selection program. The average accuracy of weaning weight EPD for males
and females in the herd is 0.65 He still selects the same percentage of animals and the ages in the
herd don not change. What response per year will he achieve with this selection program?
2. A shee producer is interested in calculating a selection index EBV for 60-day weight for two
of his rams. Ram #1 has 75 progeny and averaged 4lbs above their contemporary group mean.
Ram # 2 has no progeny, but has 100 half sibs. These sibs averaged 6lbs above their
contemporary group mean. Assume heritability of 60-day weight is 0.25
a. Caculate the estimated breeding value and accuracy for rams #1 and #2
b. which ran should the producer choose and why
c. why does one of the rams have better data and the other have a better EBV?
3. In the german genetic evaluation of jumping horses, EBV are calculated for performance in
young horse competitions (TSP), performance in older horse competitions (ABP), 1-day tes free
jumping (ZSP) 100-day test free jumping (HPF-F) and 100-days test under-saddle jumping
(HLP-S). Below is a list of 5 stallions with the EBV calculated by a BLUP national evaluation.
In this evaluation, the average EBV for each trait is set to 100. A breeder is selecting 2 stallions
for use in her herd.
Stallion
TSP
ABP
ZSP
HLP-F
HLP-S
Index
1
96
99
87
104
98
95.75
2
145
106
132
140
143
131.125
3
106
95
100
110
113
103.125
4
101
110
99
107
111
5
133
135
128
129
120
A. If she decides to use tandem selection with 100-day under-saddle jumping as the first trait
which 2 stallions will she choose?
B. if she decides to use tandem selection with performance in older horse competitions as the first
trait which 2 traits will she choose?
C. If she decides select on young and old horse competition results by independent culling level
and sets the levels at TSP >105 and ABP>105 which 2 stallions will she choose?
D. The German evaluation calculates a pseudo economic selection index. They don’t calculate
exact economic weights for each trait, but they’ve determined that for the overall goal of
improving jumping ability, TSP is worth 25%, ABP is worth 25%, ZSP is worth 25%, HLP-F is
worth 12.5%, and HLP-S is worth 12.5% write out the equation for this index.
E. calculate the missing index values in the table
F. using this index, which 2 stallions will
she choose
6. Name 2 advantages and 2 disadvantages of economic selection indexes compared to other
methods of multiple trait selection