ANSC 313 Lecture Notes - Lecture 2: Weighted Arithmetic Mean, Data Comparison, Heritability
LECTURE 5!
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Selection and mating strategies!
Selection!
goal setting is critical!•
improvement goals that include more than 3-5 traits are very difficult to implement!•
want to be different or change something that has been happening!•
!
correlated responses!
positive!•
milk yield : protein yield (both increase)!◦
negative!•
broiler size increase : fertility decreases!◦
negative does not mean detrimental!•
positive doesn't mean beneficial!•
on hand out!•
!
how are multiple traits selected for simultaneously ( THREE MAIN ONES)!
independent culling levels!•
select for minimum value per characteristics!◦
i.e. every breeding animal > minimum for every trait in the goal set, no averaging!◦
example: R.O.P Bulls ( recored of performance)!◦
30 cm scrotal circumference!‣
"pass" on feet & legs!‣
> average weight gain for breed!‣
useful for "multipurpose" animals!◦
potentially culls many animals!◦
Tandem selection!•
selects for most important trait this season, 2nd trait next season, eat.!◦
i.e. sequential election of traits not simultaneous!◦
efficient if ALL desire trait are positively correlated!◦
in reality- used primarily as a temporary selection to focus on the most important trait!◦
i.e. egg size ( ignoring number, color, shape of eggs)!‣
index selection!•
use a formula to simultaneously select for several traits, emphasizing some more than ◦
others!
example: boar selection index!◦
&&11+ 17.7 (ADG/varitation for grain)!
&&&- 17.7 ( fate deviations/ variation for fat!
¬e : feed efficiency recognized as important but difficult to measure with group penning!
if you want something you add it!◦
if you don't want it you subtract it!◦
seeing eye dog selection index!•
she felt breeding the correct dogs was needed since donated dogs didn't typically do well!◦
&&conformation!
&&working ability!
&&intelligence!
&&soundness !
take these categories and see which dog does the best in all of these and use that dog!◦
versatile hunting dog testing system!‣
