Breeding Systems in Commercial Swine Farming

What is breeding?

Animal breeding is the selective breeding of domestic animals with the intent to improve desirable and heritable qualities in the next generation.

Common breeds of pigs in Uganda. Click for additional information 

·         Yorkshire/Large White.

·         Duroc.

·         Landrace.



·         Large white.

·         Hampshire

What to consider before choosing a breed?

Each breed has a unique trait over the other. Most commercial farmers mate different breeds to benefit from the heterotic potential of the offsprings. This is because the offspring have qualities of both parents.

For example:

Duroc has faster growth ability, Yorkshire has good mothering traits and Hampshire exhibits good muscling traits. A breeding program involving Yorkshire, Duroc and Hampshire produces offsprings with growth ability, good mothering and muscling traits.

There are companies specialized in breeding, however, many farmers carry out breeding programs on their farms.

In today’s article, we shall discuss the different breeding systems and programs you should follow to improve your herd.

In general, there are two main systems of breeding i.e.

· Straight breeding.

· Crossbreeding.

1. STRAIGHTBREEDING.

This breeding system involves mating animals of the same breed. It is classified into:

· Inbreeding  

· Outcrossing   

· Grading up and 

· Purebred breeding.

a.Inbreeding.

Inbreeding is the mating of individuals that are related. It is further subdivided into:

· Closebreeding: Closely related animals are mated e.g. a backcross between a parent and an offspring.

· Linebreeding: Involves mating individuals that are more distantly related for example a cross between halfsiblings.

     b. Outcrossing.

This is the mating of animals of the same breed, but which have no closer relationship than at least 4-6 generations. This is intended to introduce desirable traits into the breeding program.

 c. Grading up.

Is the mating of purebred sires to grade the females with the aim of quickly changing from one breed to another. Sires of the desired breed are continually backcrossed to the females from the previous generation the end of the F5, the offsprings fully resemble the desired parental breed.

 d. Purebred breeding:

A purebred animal is an animal of a breed, which has the characteristics of the breed of the parents. Purebred animals are homozygous i.e. have identical genes for a particular trait and do not have heterotic potential over their parents.

In pigs and poultry, purebred lines are used to produce crossbreeds for the market.

2. CROSSBREEDING (HYBRIDIZATION):

Crossbreeding is the mating of two animals of different breeds producing a hybrid. The offspring is heterotic i.e. has a higher hybrid vigour. This is due to the combination of desirable traits from both parents. A breeder MUST follow a good performance selection program, management, nutrition and herd health practices to achieve desired goals.

Crossbreeding is divided into:

· Rotational crossbreeding and

· Terminal crossbreeding.

a. Rotational breeding:

In this breeding system, two, three or four different breeds of boars are mated in an organized rotational way with the selected females from the previous generations. It is divided into:

· Two breed rotation

· Three breed rotation

i.Two breed rotation (crisscross rotation):

Boars of two different breeds are used in alternating generations and crossbred sows resulting from this mating program are bred back to the breed of the grandsire on the dam side.

For example, a cross between Landrace × Yorkshire sow, F1 × Yorkshire boar, F2 × Landrace boar, etc.

  ii. Three breed rotation (triple crossing). 

Boars of three different breeds are used and such a rotation yields about 86% of the advantage obtained from different breeds of boars or mates. An example would be a cross between Duroc × Yorkshire sows, F1 × Hampshire boar, F2 × Yorkshire boar.

In such a selection criterion, Duroc is selected for its growth ability, Yorkshire for good mothering traits and the Hampshire for muscling traits.

b. Terminal cross-system:

The crossbred F1 females with superior maternal traits are crossed with a boar with desired traits such as carcass quality and rate of gain. All the F2 offsprings are sent to the market implying that the breeder either keeps a separate breeding stock or purchases from other breeders.

This breeding system can be broken down into:

· Two-breed,

· Three-breed and

· Four-breed terminal cross.

i. The two-breed cross.

Uses one breed of purebred boars to mate with another breed of purebred sows to produce the F1 offsprings. The dam line is selected for its mothering ability and reproductive potential whereas the sire line for carcass quality and growth rate.

The F₁ offsprings are marketed either for slaughter or to commercial farms as breeding stock.

  

The producer reaps all the benefits of the crossbred pig, however, 

• the herd has no maternal hybrid vigour as all the sows are all purebred.
•  the producer must continue buying replacer gilts.

An example is a cross between Hampshire boars and Yorkshire sows.

ii. The three-breed cross.

Crossbred females (F1) from two purebreds are mated with a sire of another breed, for example, Landrace ×Yorkshire, F1 × Duroc sire. The F2 offsprings have a genetic makeup of 50% D, 25% L and 25% Y.

Advantages:

This system maximizes heterosis since the crossbred sows produce market pigs.

Disadvantages:

The producer must continue buying the replacer gilts from another breeder.

iii. The four-breed cross.

A crossbred boar from two purebreds with good carcass characteristics and a crossbred sow from two purebreds with good reproductive potential are used.

 This system has the same advantages on the maternal side as the three-breed cross though there are some more conception rate benefits associated with use in crossbred boars. The genetic makeup of the marketed offsprings is 25%.