beef production lec 5 and 6 Flashcards Preview

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Flashcards in beef production lec 5 and 6 Deck (29):

define breeding objective how would you create one

- set genetic direction for breeding herd
o use selection to achieve


define SMART

o Specific
o Measurable
o Achievable
o Realistic
o Timely


what would you consider when setting the BO

- Achieving B/O
o look at market specs
 gives times and weights wanted
• know what to aim for
o look at operation limitations
 feed supply
 can nutrition support targets


what is the difference between a breeding vision and BO?

- overall/broad idea of what you want to achieve
o e.g. produce fertile cows
- BO measurable way to achieve the overall breeding vision e.g. produce a calf every 12 months per cow


what is a selection criteria

- allows desired traits to be identified and objectively measured
o e.g. temp, fertility
 +ve of calm cows: less bruising, less dark meat (undesirable) lower pH


what are the 5 main selection tools

live animal assessment
structural assessment


what is a structural assessment?

o objectively measure of conformation
o e.g. foot angles, temp score


what is a live animal assessment?

o BCS, fat and muscle scoring
o physical data on animal, influenced by enviro


what is MAS and when is it used

o for traits hard to access in the live animal
o measure performance from birth
o e.g. marbling, tenderness


when can genomics be used for beef cattle?

o more for dairy, beef have all info from birth
o growth area
o better prediction info to combine EBVS
o genetic conditions


how can ease of calving be achieved

for heifers, have a low BW without having EBV values below average for 440/600 day weights


what are examples of high and low heritable traits

 the ability of a trait to be passed on the next generation
 high
• carcass related
o e.g. BW, weight, fat, muscle
 low
• fertility related
o e.g. calving ease, days to calving


what would be selected for in a grass fed system?

 greatest weightings
• 600 day weight
• calving ease


what would be selected for in a long fed system?

 greatest weighting
• 600 day weight
• intramuscular fat


when would a long fed index be used?

o Long fed index
 more Japanese markets
• biggest profit drivers
o marbling
 want high marbling
o sale LW
o saleable meat%


where are the biggest profits in long fed systems in comparison to heavy grass fed?

o Long fed index
 more Japanese markets
• biggest profit drivers
o marbling
 want high marbling
o sale LW
o saleable meat%

 greatest profit drivers
• sale LW
• saleable meat %


what is a selection index and when can it be used?

o Economic weighting of EBV’s
 “$ net profit per cow mated”
o Eg. Bull A -index of $60, Bull B – index of $80, joined to 100 cows
 ½ x $20 x 100
 $1000
 $1000 better off going for bull B


what is accuracy in relation to EBVS

o accuracy
 increased accuracy has increased data
 indication of how reliable EBV is


what EBVs measure carcass

o Carcass
 more positive better
 eye muscle area
 fat depth
 marbling
 CW


what EBVS measure calving/fertility

scrotal score
gestation length
days to calving
calving ease


How is scrotal score EBVs used

 scrotal score
• higher SC increased semen production, earlier age to puberty and heifer progeny, favourable to days to calving, (shorter in daughters)


what is the advantage of a low EBV for gestation length

 gestation length
• number of days from conception to calving
• shorter = lighter calf, improved calving ease and rebreeding, heavier at weaning (have more days of growth)
• lower better


what is the relation of EBVS to days to joining

 days to calving
• re-join earlier, better calving %


what are the 3 traits used in the calving ease index

• calving difficulty score, BW and gestation length

cannot compromise on 400/600 day weight though


how is MW related to production and EBVS

 MW
• LW at 5 years
• cow feed requirements
o lower MW eat less, lower feed requirements easier to maintain
• cull values
o higher MW cows worth more (paid per kg)


what is the importance of 200, 400 and 600 day weights in EBVS?

 200 day growth
• measure of growth to weaning
 400 day weight
• important for selling as yearlings
 600 day weight
• important for breeders and those targeting heavy weight fed markets


what is the 200 milk weight in EBVS

• kg of calf LW @200days
• expected difference in calf weight due to maternal affect
• higher the better (if can match increased milk production with nutrition)


what is an EBV?

o gives the genetic merit of the animal in comparison to the average
o higher generally better


what are the EBV related to weight

BW, milk, 200/400/600 day weight and MW