Systems of 2 basic Breeding - Straight breeding * Mating animals of the same breed * Variations-purebred, inbreeding, outcrossing, grading up -Cross breeding * Mating animals of different breeds * Variations-two-breed cross, three-breed cross, rotation

* An animal of a particular breed * Both parents are purebred * Characteristics of the breed * Eligible for registry in breed association * Tend to be genetically homozygous * Specialized business

* An animal of a particular breed * Both parents are purebred * Characteristics of the breed * Eligible for registry in breed association * Tend to be genetically homozygous * Specialized business

Purebred
Breeding

* Mating related animals * Linebreeding and Closebreeding refer to how closely related the animals are * Requires a careful program of selection and culling * Expensive * Used most often by Universities for experimental work and Seedstock producers that provide animals for crossbreeding herds * Mating related animals * Linebreeding and Closebreeding refer to how closely related the animals are * Requires a careful program of selection and culling * Expensive * Used most often by Universities for experimental work and Seedstock producers that provide animals for crossbreeding herds

Inbreeding

* Most intensive * Animals are very closely related and can be traced back to more than 1 common ancestor * Examples: * Sire to daughter * Son to dam * Brother to sister

* Most intensive * Animals are very closely related and can be traced back to more than 1 common ancestor * Examples: * Sire to daughter * Son to dam * Brother to sister

Closebreeding

Example:
1st Mating

1st Mating

A (Male) B (Female)
A (Male) B (Female)

¾ A ¼ B
¾ A ¼ B
2nd Generation
2nd Generation
A 1/2A 1/2B (Sire to daughter)

A 1/2A 1/2B (Sire to daughter)

2nd Mating
2nd Mating
1/2A 1/2B
1/2A 1/2B
1st Generation
1st Generation

* Mating animals that are more distantly related * Can be traced back to 1 common ancestor * Examples * Cousins * Grandparents to grand offspring * Half-brother to half-sister * Increases genetic purity * Several generations results in desirable and undesirable genes to become grouped together with greater frequency—making culling easier

* Mating animals that are more distantly related * Can be traced back to 1 common ancestor * Examples * Cousins * Grandparents to grand offspring * Half-brother to half-sister * Increases genetic purity * Several generations results in desirable and undesirable genes to become grouped together with greater frequency—making culling easier

Linebreeding

example

* Mating of animals of different families within the same breed * Animals are not closely related * Purpose is to bring into the breeding program traits that are desirable but not present in the original animals * Used most by purebred breeders * Popular because it reduces the chances of undeniable traits are still present * Sometimes used in inbreeding programs to bring in needed traits

* Mating of animals of different families within the same breed * Animals are not closely related * Purpose is to bring into the breeding program traits that are desirable but not present in the original animals * Used most by purebred breeders * Popular because it reduces the chances of undeniable traits are still present * Sometimes used in inbreeding programs to bring in needed traits

Outcrossing

* Mating animals from two different lines of breeding within a breed * Purpose is to bring together desirable traits from different lines * Experience is the best guide to use when line crossing

* Mating animals from two different lines of breeding within a breed * Purpose is to bring together desirable traits from different lines * Experience is the best guide to use when line crossing

Linecrossing

* Mating purebred males to grade females * Good way to improve quality * Less expensive * Use of purebred sires long enough will eventually lead to the amount of grade breeding left in the offspring being less than 1%

* Mating purebred males to grade females * Good way to improve quality * Less expensive * Use of purebred sires long enough will eventually lead to the amount of grade breeding left in the offspring being less than 1%

Grading up

Mating

* Mating two animals of different breeds * Offspring is a Hybrid * Usually results in improved traits because dominant genes mask undesirable recessive genes * Superior traits that result from crossbreeding are called hybrid vigor or heterosis

* Mating two animals of different breeds * Offspring is a Hybrid * Usually results in improved traits because dominant genes mask undesirable recessive genes * Superior traits that result from crossbreeding are called hybrid vigor or heterosis

Crossbreeding(X)

* Good record keeping is essential * Calving difficulties may increase when crossing large breed sires with small breed dams * Fewer calving problems if large breed dams are used * Large breed dams have higher maintenance costs * Artificial insemination allows access to better bulls * To avoid inbreeding more than 1 breeding pasture may be required * Good record keeping is essential * Calving difficulties may increase when crossing large breed sires with small breed dams * Fewer calving problems if large breed dams are used * Large breed dams have higher maintenance costs * Artificial insemination allows access to better bulls * To avoid inbreeding more than 1 breeding pasture may be required

* Good record keeping is essential * Calving difficulties may increase when crossing large breed sires with small breed dams * Fewer calving problems if large breed dams are used * Large breed dams have higher maintenance costs * Artificial insemination allows access to better bulls * To avoid inbreeding more than 1 breeding pasture may be required * Good record keeping is essential * Calving difficulties may increase when crossing large breed sires with small breed dams * Fewer calving problems if large breed dams are used * Large breed dams have higher maintenance costs * Artificial insemination allows access to better bulls * To avoid inbreeding more than 1 breeding pasture may be required

General Considerations
Regarding Beef
Crossbreeding Systems

* Terminal Sire Crossed with F1 Females * Rotate Herd Bull every 3-4 years * Two Breed Rotation * Three Breed Rotation * Four and Five Breed Rotation * Static Terminal Sire * Rotational Terminal Sire * Composite Systems

* Terminal Sire Crossed with F1 Females * Rotate Herd Bull every 3-4 years * Two Breed Rotation * Three Breed Rotation * Four and Five Breed Rotation * Static Terminal Sire * Rotational Terminal Sire * Composite Systems

Beef crossbreeding
Systems

* Replacement crossbred (F1) females in the herd are purchased and crossed with a terminal bull. * All offspring are sold * Replacement crossbred (F1) females in the herd are purchased and crossed with a terminal bull. * All offspring are sold
Terminal Sire
Crossed with F1 Females

* Bulls from Breed A are crossed with cows from Breed B. * Resulting heifers are bred to bulls from breed B for the duration of their productive life. * Replacement heifers from that cross are bred to bulls from breed A. * Each succeeding generation of replacement heifers is bred to a bull from the opposite breed used to sire the replacement heifer.

* Bulls from Breed A are crossed with cows from Breed B. * Resulting heifers are bred to bulls from breed B for the duration of their productive life. * Replacement heifers from that cross are bred to bulls from breed A. * Each succeeding generation of replacement heifers is bred to a bull from the opposite breed used to sire the replacement heifer.

Two-breed
Rotation

* Same breed of bull is used for several years and then replaced with a bull of a different breed. * Replacement females are selected from the herd.

* Same breed of bull is used for several years and then replaced with a bull of a different breed. * Replacement females are selected from the herd.

Rotate Herd
Bull Every
3-4 Years

* Same pattern of breeding as the 2 breed rotation except that a bull from a 3rd breed is used in the sire rotation.

* Same pattern of breeding as the 2 breed rotation except that a bull from a 3rd breed is used in the sire rotation.

3 breed
Rotation

* Larger herds * Bulls from a 4th or 5th breed may be used in the rotation of sires * This system requires a higher level of management and record keeping than 2 and 3 breed systems.

* Larger herds * Bulls from a 4th or 5th breed may be used in the rotation of sires * This system requires a higher level of management and record keeping than 2 and 3 breed systems.

4 and 5
Breed
Rotations

* 4 breeding groups * Group 1 (25% of the herd) mates breed A bulls to breed A cows to produce replacement heifers for group 1 and group 2. * Group 2 (25% of the herd) breeds the AA heifers to a bull (breed B) to a different breed, producing crossbred heifers (breed AB) * Group 3 (50% of the herd) breeds the AB heifers to a terminal (T) bull selected for its ability to transmit a high rate of gain. * A subgroup (Group 4, 10% of the herd) of the 3rd group is composed of AB heifers being bred for the first time. These AB heifers are bred to a smaller breed (breed C) bull to reduce 1st time calving problems. * All the male offspring of groups 1 and 2 and all offspring of groups 3 and 4 are sold. * Any heifers from groups 1 and 2 that are not kept for breeding are also sold.

* 4 breeding groups * Group 1 (25% of the herd) mates breed A bulls to breed A cows to produce replacement heifers for group 1 and group 2. * Group 2 (25% of the herd) breeds the AA heifers to a bull (breed B) to a different breed, producing crossbred heifers (breed AB) * Group 3 (50% of the herd) breeds the AB heifers to a terminal (T) bull selected for its ability to transmit a high rate of gain. * A subgroup (Group 4, 10% of the herd) of the 3rd group is composed of AB heifers being bred for the first time. These AB heifers are bred to a smaller breed (breed C) bull to reduce 1st time calving problems. * All the male offspring of groups 1 and 2 and all offspring of groups 3 and 4 are sold. * Any heifers from groups 1 and 2 that are not kept for breeding are also sold.

Static
Terminal
Sire

* Two breeding groups needed * Bulls from breeds A and B are used on a rotating basis on 50% of the herd providing crossbred females for the entire herd * Mature cows in the herd are mated with a terminal bull to produce offspring, all of which are sold. * Replacement females come from mating of bulls A and B with younger cows in the herd.

* Two breeding groups needed * Bulls from breeds A and B are used on a rotating basis on 50% of the herd providing crossbred females for the entire herd * Mature cows in the herd are mated with a terminal bull to produce offspring, all of which are sold. * Replacement females come from mating of bulls A and B with younger cows in the herd.

Rotational
Terminal
Sire

* Developing a new breed based on crossbreeding 4 or more existing breeds of cattle to avoid inbreeding problems * After development the composite breed is not crossbreed with other breeds

* Developing a new breed based on crossbreeding 4 or more existing breeds of cattle to avoid inbreeding problems * After development the composite breed is not crossbreed with other breeds

Composite
Breeds