sheep genetics lec 3

Question 1

what is sheep genetics Australia and what is it used for?

Answer 1

o	Combination of lambplan and ramplan
	Lamb plan
•	Across flocks, meat sheep, uses EBV
	Ramplan
•	Within flock, wool sheep, uses EPV

o Uses ASBV can be used across flocks
o Does meat and wool sheep

Question 2

what is ASBV?

Answer 2

Standardized values, gives benchmark

estimate of an animal’s true breeding value based on pedigree and performance recorded information

Min 47
Gives accuracy values-how reliable results are
Don’t meet QA and accuracy standards, given as FBV

Question 3

How is the ASBV measured and what do the values indicate?

Answer 3

Measurements across ages
 - Birth to adult

-Values
	Based around 0	
•	0= average from 1990 drop
	Need to compare to average of that year
-	-ve not always bad e.g. FEC

Question 4

What are a few example traits of ASBV?

Answer 4

o BW, FEC, GFW, CFW, FD, no of lambs born, no of lambs weaned

Question 5

what is an index?

Answer 5

Combines ASBV for several traits into 1 value

o allows for quick selection

Question 6

Define micron premium

Answer 6

o Indicates economic advantage of reducing fiber diameter

 Generally increase value by decreasing micron

Question 7

if;
20 micron 800 c/kg
19 micron 900 c/kg

what is the micron premium?

Answer 7

 Micron premium = 900-800/800 x 100 = 12.5 %

Question 8

what does a high micron premium indicate?

Answer 8

 increased emphasis on micron (FD)

 e.g. 12% Micron P

Question 9

what does a low micron premium indicate?

Answer 9

 increased emphasis on weight/yield (FW)

 e.g. 3% Micron P

Question 10

what does a 6% micron premium indicate?

Answer 10

o 6% Micron Premium compromise, small decrease in FD small increase FW

Question 11

what is merinoselect standard indices (3)?

Answer 11

Evaulations for merinos

MP- merino production
DP- dual purpose
FP- fiber production

Question 12

What is FP index and what is the where is the biggest economic advantage?

Answer 12

o Fiber production (FP)
 Wool focused operations
 FP index
• Decrease FD = biggest economic gain %

Question 13

What is the FP + index and what is the where is the biggest economic advantage?

Answer 13

fiber production plus index

• More traits looked at = decrease selection pressure
• still decrease FD = biggest economic gain %

Question 14

What is MP index and what is the where is the biggest economic advantage?

Answer 14

o merino production (MP)
 wool focused with surplus sheep sales
 MP index
• increase BW = biggest economic gain %

Question 15

What is the MP + index and what is the where is the biggest economic advantage?

Answer 15

 MP + index
• Increased traits
• Increased no. of lambs weaned= biggest economic gain %

Question 16

What is the DP index and what is the where is the biggest economic advantage?

Answer 16

o Dual purpose (DP)
 Significant meat income
 DP index
• increase BW = biggest economic gain %

Question 17

What is DP + index and what is the where is the biggest economic advantage?

Answer 17

 DP + index

• Increased no. of lambs weaned= biggest economic gain %

Question 18

what is the advantage of using ASBV, EBV etc.?

Answer 18

 Reduced risk associated with ram selection
 Improve rate of genetic gain
 More reliably meet market specifications
 Improve overall productivity

Question 19

what is an objective and subjective measure and give an example of each

Answer 19

• Objective traits
  o Measurements
  e.g. fleece weights
• Subjective traits
  o Visual, non-measured
  E.g. wrinkle score, increases lead to increased risk of fly strike

Question 20

Why should you use both objective and subjective measures and what does this depend on?

Answer 20

includes visual and non-visual (e.g. conformation and measures) for a better quality output

depends on
o Breeding objective (meat vs wool)
o Cost
o Ram/ewe selection