Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Beef systems > Genetics > Flashcards

Genetics Flashcards

1
Q

What is breed?

A

a stock of animals within a species having a distinct appearance and typically having been developed by deliberate selection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What traits should producers focus on?

A

-economically relevant traits
-production system and feed resources
-marketing program
-current herd performance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are some economically relevant traits?

A

-calving ease
-weaning weight
-feed requirements for maintenance
-tenderness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are growth traits?

A

*birth weight (h^2= .40-.45)
*milk (h^2 = .25)
*weaning weight (.2-.25)
*yearling weight (.3-.35)
*yearling height, mature height and weight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What goes into birth weight?

A

-genetics of sire and dam
-maternal environment
-nutrition
-weather
-age of dam

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Why do cows tend to have bigger cows in the cold?

A

all their blood goes to the center of their body where the calf is

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What goes into weaning weight?

A

-genetics of sire and dam
-dams milk
-quantity and quality of forage
-age of dam
-age at weaning
-sex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What goes into yearling weight?

A

-weaning weight
-nutrition post weaning
-sex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are reproductive traits?

A

*fertility (h<.10)
*calving difficulty (.12-.20)
*scrotal circumference (.45-.5)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are carcass traits?

A

*marbling (.35)
*carcass weight (.40)
*ribeye area (.37)
*fat thickness (.44)
*yield grade (.36)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Other traits?

A

-soundness
-temperament
-feed efficiency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Breeds in general

A

-more than 250 worldwide
-more than 80 in US
-only 10-15 breeds make a significant contribution to total number of cattle in US

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

British Breeds

A

-originated in British Isles
-generally smaller in size but have increased fleshing and marbling abilities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Continental Breeds

A

-originated in Europe
-“Exotics”
-known for weight gain and cutability
-large in size, lean, muscular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Bos indicus

A

“american breeds or synthetic breeds”
-increased heat tolerance
-pest resistant, disease resistant
-tough meat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Black Angus (British)

A

-most registrations annually
-black color, polled
-calving ease, meat quality
-originated by Aberdeenshire Scotland, imported in 1873

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Red Angus (British)

A

-red, polled
performance breed in 1954 by selecting red animals from black angus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Hereford/Polled Hereford (British)

A

-red body with with face; horned or polled
-introduced to US in 1817, followed the longhorn in becoming range cattle
-polled developed in 1901 by selection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Shorthorn (British)

A

-red,white,roan; horned or polled
-US in 1783 from England

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are some other British Breeds?

A

belted galloway, galloway, Lincoln Red, Red Poll, Scotch highland, Welsh black

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Charolais (Continental)

A

-white color, heavy muscle, horned or polled
-one of oldest breeds in France brought to US after WW1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Simmental (Continental)

A

-yellow to red and white color or pattern or black
-prominent breed in Switzerland and France
-imported to NA in 1967
-originally selected for dual purpose breed for milk and meat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Limousin (Continental)

A

golden red color or black, heavy muscled
-from France in 1969

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Gelbvieh (Continental)

A

-golden to red or black
-originated in Austria and Germany
-developed us dual purpose breed and introduced to US in 1971 through semen importation
-“Gelb”= yellow, “Vieh” = cattle or livestock

25
Q

Brahman (Bos indicus)

A

-light gray to red to almost black
-from India, first import in 1849

26
Q

Beefmaster (Bos indicus)

A

-various colors
-developed in US from Brahman, Hereford, Shorthorn
-selection based on weight, conformation, milking ability, fertility, hardiness, disposition of range

27
Q

Brangus (Bos indicus)

A

-black, polled
-developed in US from crossing Brahman (3/8) with Angus (5/8)

28
Q

Santa Gertrudis (Bos indicus)

A

-deep,cherry red
-polled, scurred, horned
-developed by crossing Brahman (3/8) with Shorthorn (5/8)
-King ranch

29
Q

How to compare breeds?

A

best through independent center
ex: Germ plasma evaluation program at the US Meat Animal Research Center

30
Q

What are performance records?

A

record of how an individual performed for a given trait
-allow for use of EPDs

31
Q

What does the usefulness of performance records depend on?

A

-objective, accurate, honest measurements
-adjusted for environmental effects
-ability to compare differences
-contemporary group to minimize environmental effects and estimate genetic differences

32
Q

What must record keeping be?

A

-accurate
-adjusted for known environmental and management effects
-major categories: repro, growth, maternal ability, carcass, disposition

33
Q

Where are performance records measured?

A

-farm or at central testing center

34
Q

What are some examples of central testing centers?

A

-bull test
-heifer development programs
-feedlot/carcass evaluation programs

35
Q

Whats a bull test?

A

-records differences in ability of bulls to gain in uniform environment
-value of records
-aids in breeders in marketing

36
Q

Heifer Development Programs

A

-developed for replacement breeding stock
-uniform development
-marketing option

37
Q

Feedlot/carcass development

A

-producers consign cattle
-fed and carcass data collected
-producers are paid on USDA yield and quality grade basis with expenses deducted from animal value
-allows smaller producers to retain ownership
-obtain feedlot and carcass performance info

38
Q

Matching genetics to resources

A

maximum productivity vs maximum profitability

39
Q

What are the different mating systems?

A

-inbreeding
-linebreeding
-outcrossing
-grading up
-linecrossing
-crossbreeding
-species crossing

40
Q

Commercial cattle should crossbreed. Why?

A

-breed complementary
-heterosis

41
Q

crossbreeding questions to ask

A

-what is the appropriate grazing system?
-what is the cost of labor?
-what is the importance of a breeding program?
-cost of AI?
-marketing plan?

42
Q

Reasons crossbreeding fail to achieve desired results?

A

-breeds with too much growth, milk, birth weight are over used
-mating system is too complex or not used in systematic system
-seedstock producers fail to develop expertise and service orientation to assist clients in development of effective crossbreeding systems
-poor quality bulls are used

43
Q

What is selection?

A

practice of determining which individuals will become parents
-natural vs AI
-change is inevitable, but progress is optional
-choice of appropriate goals is more important than how they are accomplished

44
Q

What are selection goals?

A

-initial step in genetics improvement
-clear pictures of desired genetic change
-guides day to day decisions
-without goals, progress suffers

45
Q

Goals for angus? (goals should be related to breed characteristics)

A

-low birth weight/ calving ease
-carcass weight

46
Q

What are the types of selection?

A

-tandem
-independent culling level
-selection index

47
Q

Tandem selection

A

select one trait at a time
-once at desired level, select for second trait
-least effective

48
Q

Independent culling level

A

-minimum culling levels for each trait
-most common type used
DIS: could be slightly below min for one trait but superior in another but still culled

49
Q

Selection index

A

*most effective
-put weight on selected traits
-difficult to instruct

50
Q

What are selection methods?

A

-pedigree
-individual appearance of performance
-progeny testing

51
Q

Pedigree

A

-most useful for animals which progeny info is not available
-useful for traits later in life or sex limited traits (milk production)

52
Q

Individual appearance

A

-widely used
-best used for highly heritable traits
-permits rapid generation turnover and shorter generation intervals

53
Q

Progeny testing

A

-more accurate for low heritability traits
DIS:
-limited number of tests
-longer generation interval
-poorly conducted tests can lead to misleading results

54
Q

EPDs (expected progeny differences)

A

-allow for comparison of animals across herds
-traits available differ with breed
-pedigree estimate EPDs available for animals without data

55
Q

What is marker-assisted selection?

A

selection for specific alleles using genetic markers
-several gene markers available commercially (black coat color, polled, genetic disorders)
-genomic enhanced EPDs
-breeds are moving to single-step procedure incorporate genomic information

56
Q

Selection index

A

good selection index will use statistical methods to include heritability, economic value, genetic correlations and variability for multiple traits in a single formula

57
Q

Across breed EPD adjustments are

A

most useful to commercial producers purchasing bulls for use in crossbreeding programs
emphasize:
-uniformity for rotational crossbreeding
-divergence for terminal crossbreeding
-divergence for birth weight EPDs for bulls to breed to first calf heifers

58
Q

Accuracy of across breed EPD depends on

A

accuracy of within breed EPD for bull
-only apply to EPDs from the most recent sire summaries

59
Q

Multiple Breed international cattle evaluation

A

use a common base to allow direct comparison

Beef systems (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions