Breeding Systems in Livestock

Flashcards covering breeding systems for livestock, including straightbreeding and crossbreeding methods, their purposes, and specific examples in cattle, swine, and sheep.

Straightbreeding

Mating animals of the same breed, resulting in purebred offspring.

Purebred

An animal of a particular breed that has the characteristics of the breed to which it belongs; both parents must also be purebred, and they are eligible for registry.

Inbreeding (or Closebreeding)

Mating of closely related individuals (e.g., sire to daughter, mother to son, brother to sister) to increase homozygosity for desired traits and decrease gene variation.

Linebreeding

Mating of less closely related individuals than with inbreeding (e.g., grandparent-offspring, half siblings, cousins) tracing back to one common ancestor, to increase homozygosity for desired traits.

Outcrossing

Mating of animals of different families within the same breed to introduce desirable traits not present in the original animals.

Linecrossing

Mating animals from two different lines of breeding within a breed to combine desirable traits from different lines.

Grading up

Mating of purebred sires to grade females to improve the quality of animals on a farm, with the greatest improvement occurring in the first cross.

Grade animals

Any animal not eligible for registry in a purebred association.

Crossbreeding

Mating individuals from different breeds to produce offspring with more heterozygous gene pairs, thereby increasing hybrid vigor or heterosis.

Heterosis (or Hybrid Vigor)

The average superiority of hybrid offspring over the average of their parents, often seen more in traits with low heritability.

Terminal Sire

A bull (or boar/ram) whose offspring are intended solely for market and are not used for breeding purposes.

F1 Females

First generation crossbreed females that have been purchased or bred.

Two-breed rotation (Beef Cattle)

A crossbreeding system involving two breeds, where bulls of one breed are mated to cows, and their replacement heifers are then mated to bulls of the other breed, and so on.

Rotational-terminal sire system (Beef Cattle)

A crossbreeding system using at least two breeds, where bulls rotate to produce crossbred females, and these females/replacements are then bred to terminal sires for market offspring.

Static Terminal sire system (Beef Cattle)

A complex crossbreeding system (often using at least 4 breeds) where specific breeding groups produce replacement heifers and crossbred heifers that are eventually bred to terminal sires for market.

Rotational crossbreeding (Swine)

A crossbreeding system for swine similar to cattle, employing two to five breeds in rotation.

Terminal crossing system (Swine)

A swine crossbreeding system where crossbred F1 females are mated to terminal boars, with all offspring going to market, requiring replacement females to be purchased or retained.

Rotaterminal system (Swine)

A swine crossbreeding system where crossbred F1 females are produced through rotating boars, and these female offspring are then mated to terminal boars, with all offspring destined for market.

Rotational (Sheep)

A sheep crossbreeding system similar in concept to those used in swine and beef cattle.

Static (Sheep)

A sheep crossbreeding system involving purchasing replacement crossbred ewes and breeding them to a terminal ram to produce market lambs.

Rotostatic (Sheep)

A combination sheep crossbreeding system where replacement ewes are produced from the flock itself, and these are then mated to terminal rams to produce market lambs.