slide1 l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Applied Beef Cattle Breeding and Selection Composite Populations PowerPoint Presentation
Download Presentation
Applied Beef Cattle Breeding and Selection Composite Populations

Loading in 2 Seconds...

play fullscreen
1 / 24

Applied Beef Cattle Breeding and Selection Composite Populations - PowerPoint PPT Presentation


  • 236 Views
  • Uploaded on

Applied Beef Cattle Breeding and Selection Composite Populations . Larry V. Cundiff ARS-USDA-U.S. Meat Animal Research Center. 2008 Beef Cattle Production Management Series-Module V Great Plains Veterinary Education Center University of Nebraska, Clay Center September 18, 2008.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Applied Beef Cattle Breeding and Selection Composite Populations' - Mia_John


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

Applied Beef Cattle Breeding and Selection

Composite Populations

Larry V. Cundiff

ARS-USDA-U.S. Meat Animal Research Center

2008 Beef Cattle Production Management Series-Module V

Great Plains Veterinary Education Center

University of Nebraska, Clay Center

September 18, 2008

slide2

Estimating Heterosis for a specific two breed cross

HA = 430 = .5gH + .5 gA + hIha + mA

AH = 416 = .5gH + .5 gA + hIha + mH

AA = 405 = gA + + mA

HH = 395 = gH + + mH

(.5)(HA + AH) - .5 (AA + HH) = 423 – 400 = 23 = hIah

slide3

HA = 430 = .5gH + .5 gA + hIha + mA

  • AH = 416 = .5gH + .5 gA + hIha + mH
  • AA = 405 = gA + + mA
  • HH = 395 = gH + + mH
  • In the above equations,
    • HA denotes a crossbred calf with a Hereford sire and an Angus dam.
    • AH denotes a crossbred calf with an Angus sire and a Hereford dam.
    • HH denotes a straightbred calf with a Hereford sire and Hereford dam.
    • AA denotes a straightbred calf with an Angus sire and Angus dam.
    • gH denotes the additive breed effect for Herefords and gA the additive breed effect for Angus.
    • hIha denotes effect of individual hetersosis expressed by Hereford X Angus or Angus X Hereford reciprocal crosses. Note that hIha = hIha.
    • mA denotes the maternal (MILK) breed effect for Angus and mH the maternal breed effect for Hereford dams.
slide4

Estimating Maternal Heterosis

C X A = .5gC + .5 gA + hIca + mA

C X B = .5gC + .5 gB + hICB + mB

C X AB = .5gC + .25 gA + .25gB + .5hIAC + .5hIBC + .5mA +

.5 mB + hMAB

C X BA = .5gC + .25 gB + .25gA + .5hIAC + .5hIBC + .5mA +

.5 mB + hMAB

.5[( C X AB) + (C X BA)] – .5[(C X A) + (C X B)] = hMAB

slide5

C X A = .5gC + .5 gA + hIca + mA

C X B = .5gC + .5 gB + hICB + mB

C X AB = .5gC + .25 gA + .25gB + .5hIAC + .5hIBC + .5mA +

.5 mB + hMAB

C X BA = .5gC + .25 gB + .25gA + .5hIAC + .5hIBC + .5mA +

.5 mB + hMAB

In the above equations,

the gA, gB and gC denote additive breed effects for breeds A, B and C respectively.

hICA, hICB and hIAC denote individual heterosis effects for C X A (or A X C) , C X B (or B X C) , and A X C (or C X A) breed crosses, respectively.

mA and mB denote maternal (MILK) breed effects for breeds A and B, respectively.

hMAB denotes maternal heterosis expressed by A X B (or B XA) crossbred dams.

slide6

Composite populations can be used to exploit:

    • HETEROSIS
    • COMPLEMENTARITY among breeds optimize performance levels for important traits and to match genetic potential with:
  • Market preferences
  • Feed resources
  • Climatic environment
slide7

MARC I

¼ Limousin, ¼ Charolais,

¼ Brown Swiss,

c Angus and c Hereford

MARC II

¼ Simmental, ¼ Gelbvieh,

¼ Hereford and ¼ Angus

MARC III

¼ Pinzgauer, ¼ Red Poll,

¼ Hereford and ¼ Angus

Limousin

Simmental

Pinzgauer

Charolais

Gelbvieh

Red Poll

Brown Swiss (Braunvieh)

Hereford

Hereford

Angus

Angus

Angus

Hereford

slide8
HETEROSIS EFFECTS AND RETAINED HETEROSISIN COMPOSITE POPULATIONS VERSUS CONTRIBUTINGPUREBREDS (Gregory et al., 1992)

Composites minus purebreds

Trait F1 F2 F3&4

Birth wt., lb 3.6 5.0 5.1

200 d wn. wt., lb 42.4 33.4 33.7

365 d wt., females, lb 57.3 51.4 52.0

365 d wt., males, lb 63.5 58.6 59.8

Age at puberty, females, d -21 -18 -17

Scrotal circumference, in .51 .35 .43

200 d weaning wt., (mat.), lb 33 36

Calf crop born, (mat.), % 5.4 1.7

Calf crop wnd., (mat.), % 6.3 2.1

200 d wn. wt./cow exp. (mat.), lb 55 37

composite populations maintain heterosis proportional to heterozygosity n 1 n or 1 s p i 2
Composite populations maintain heterosisproportional to heterozygosity(n-1)/n or 1 – S Pi2
slide10

MODEL FOR HETEROZYGOSITY IN

A TWO BREED COMPOSITE

Breed Breed of sire

Dam ½ A ½ B

½ A ¼ AA ¼ AB

½ B ¼ BA ¼ BB

(n-1)/n or 1 – S Pi2 = .50

slide11

MODEL FOR HETEROZYGOSITY IN

A THREE BREED COMPOSITE

Breed Breed of sire

Dam .50 A .25 B .25 C

.50 A .25 AA .125 BA .125 CA

.25 B .125 BA .0625BB .0625 CB

.25 C .125 AC .125 BC .0625CC

1 – S Pi2 = (1 - .375) = .625

slide12

Weaning Wt Marketed Per Cow Exposed for Alternative Crossbreeding Systems Relative to Straightbreeding (%)

Wean. wt

H i Hm marketed

System (+ 8.5%) (+14.8%) per cow exp

Straight breeding 0 0 0

2-breed rotation (A,B) .67 .67 15.5

3-breed rotation (A,B,C) .86 .86 20.0

4-breed rotation (A,B,C,D) .93 .93 21.7

2-breed composite (5/8 A, 3/8 B) .47 .47 11.0

2-breed composite (.5 A, .5 B) .5 .5 11.7

3-breed composite (.5A, .25 B, .25C) .625 .625 14.6

4 breed composite (.25A,.25B,.25C,.25D) .75 .75 17.5

F1 bull rotation (3-breed: AB, AC) .67 .67 15.5

F1 bull rotation (4-breed: AB, CD) .83 .83 19.3

slide13
Composite populationsprovide for effective use of
  • Heterosis
  • Breed differences
  • Uniformity and end product consistency
slide14

Genetic Variation in Alternative Mating Systems

Optimum

Assumes that the Two F1’s Used are of Similar Genetic Merit

slide15

Genetic potential for USDA Quality Grade and USDA Yield Grade is more precisely optimized in cattle with 50:50 ratios of Continental to British breed inheritance.

cefficients of variation in purebred and composite populations gregory et al 1992
CEFFICIENTS OF VARIATION IN PUREBRED AND COMPOSITE POPULATIONS (Gregory et al., 1992)

Trait Purebreds Composites

Gestation length, d .01 .01

Birth wt. .11 .12

200 d wn. wt. .09 .09

365 d wt., females .08 .08

365 d wt., males .09 .09

Age at puberty (females) .08 .07

Scrotal circumference .07 .07

5 yr cow wt, lb .07 .08

5 yr height, in .02 .02

Steer carcass wt, lb .08 .08

Rib-eye area .10 .10

Retail product, % .04 .06

Retail product, lb .19 .20

slide17

COMPLEMENTARITY

is maximized in terminal crossing systems

Terminal Sire Breed

Rapid and efficient growth

Optimizes carcass composition

and meat quality in

slaughter progeny

  • Cow Herd
  • Small to moderate size
  • Adapted to climate
  • Optimal milk production
    • for feed resources

Progeny

Maximize high quality lean beef

produced per unit feed consumed

by progeny and cow herd

slide18

Rotational and Terminal Sire

Crossbreeding Programs

Two Breed Composite

Cow

Age No.

1 20

2 18

3 15

2Breed Rotation

A

B

1/2A - 1/2B

45%

4 13

5 12

- -

- -

12 1

T x (A-B)

T x (A-B)

55%

Lbs. Calf/Cow

18%

21%

slide19

Weaning Wt Marketed Per Cow Exposed for Alternative Crossbreeding Systems Relative to Straightbreeding (%)

Wean. wt Terminal

H i Hm marketed crossa

System + 8.5% +14.8% per cow exp (+5% wt/calf)

Straight breeding 0 0 0 0

2-breed rotation (A,B) .67 .67 15.5 20.8

3-breed rotation (A,B,C) .86 .86 20.0 24.1

4-breed rotation (A,B,C,D) .93 .93 21.7 25.4

2-breed composite (5/8 A, 3/8 B) .47 .47 11.0 17.3

2-breed composite or F1 bulls (.5 A, .5 B) .5 .5 11.7 17.8

3-breed composite (.5A, .25 B, .25C) .625 .625 14.6 20.3

4 breed composite (.25A,.25B,.25C,.25D) .75 .75 17.5 22.2

F1 bull rotation (3-breed: AB, AC) .67 .67 15.5 20.8

F1 bull rotation (4-breed: AB, CD) .83 .83 19.3 23.6

a Assumes 66 % of calves marketed (steers and heifers) are by terminal sire breed out of more mature age dams and 33% are by maternal breeds (steers only).

general considerations
General Considerations
  • Rotational Systems

Provide for more effective use of

      • Heterosis
  • Composite populations

Provide for more effective use of

      • Breed differences
      • Uniformity and end product consistency
slide22

Figure 6. Use of heterosis, additive breed effects and

Complementarity with alternative crossbreeding systems.

slide23

Implications for Crossbreeding

  • Advantages of terminal sire crossing systems are not as great today as 30 years ago due to similarity of breeds for rate and efficiency of growth.
  • However, differences between British and Continental breeds in carcass traits are still significant and relatively large.
  • Inter generation fluctuations in mean performance for carcass traits are still large and significant.
  • For carcass traits, uniformity and end-product consistency can still be enhanced by use of composite populations or hybrid bulls.
  • Adaptation to intermediate subtropical/temperate environments can be optimized with greater precision by use of composite populations or hybrid bulls.
slide24
Module IV Applied Animal Breeding and Selection

Homework questions assigned September 18

To be returned by October 23, 2008

(Email to: larry.cundiff@ars.usda.gov)

The Brangus breed has a genetic composition of 5/8 Angus and 3/8 Brahman breeding.

1) What is the expected heterozygosity or level of Brahman X Angus heterosis expected in the Brangus breed (show work)?

2) How would you expect the effect of heterosis for Brangus to compare to that in a breed with a composition of 5/8 Angus and 3/8 Shorthorn, why or why not? (In other words, would effects of heterosis be the same, or more, or less for Brahman X Angus crosses than for Angus X Shorthorn crosses, why or why not?)

3) What is the expected level of heterosis in a four breed composite founded with ¼ breed A, ¼ breed B, ¼ breed C, and ¼ breed D inheritance (show work)?

4) State the location and describe a typical production environment for cow herds where you reside or provide service.

5) If you were to develop a composite population adapted to this production environment, what foundation breeds would you select?

6) What proportions of each breed would you use in the composite population?

7) What would the expected level of heterosis be in your composite population (show work)?

8) Why would you select these breeds (Discuss the merits of each breed selected for additive direct and maternal breed effects).