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Publication #RFAA083

Swine: Selection and Mating of Breeding Stock 1

Randy Walker2

Selection of Gilts

Select gilts to be retained for the breeding herd at five to six months of age or when they weigh 200 lb or more. Separate from the market herd and grow them out on 4–6 lb of a balanced 14–15% protein ration.

Criteria for Herd Replacement

Gilts selected for herd replacements should meet the following criteria:

  1. Select gilts that do not have any hereditary defects and are from lines that do not have a history of hereditary defects.

  2. Twelve or more prominent teats and from sow lines that have high milk production.

  3. From lines and or families with high fertility rate noted for large litters and early sexual maturity.

  4. Large frame, structurally correct individuals with adequate bone and proper set to feet and legs.

  5. Healthy individuals from healthy sows.

  6. Gilts should indicate a rapid rate of gain and have good feed efficiency.

  7. Lean with ample muscling.

  8. Where possible, use litter mate and sire records from Swine Evaluation Centers.

Gilts should be fed a balanced ration (refer to Swine: Feeding, Table 16 of Document AA084) such that they will meet their genetic potential at breeding time and weigh approximately 220–280 lb without being overly fat (6–8 months of age).

Breed gilts during their second or third heat period (6–8 months). They should be bred on first day heat is observed and rebred 12 to 24 hours later if possible.

  1. In a commercial herd, double mating (best to use two different boars) may be employed. Research indicates an increase in litter size by approximately 1–1 1/2 pigs per litter by following the practice of breeding a second time 12-24 hours after the first service.

  2. In a purebred herd, use the same sire for the second breeding.

  3. Sows can be bred in the post weaning heat if pigs are weaned at 2 weeks of age or older and the sow is not in too thin a condition.

  4. Boars should be approximately seven to eight months old before being used in a breeding herd. The boar is considered to be mature at 15 months of age or older. The suggested maximum number of services per boar are listed in Table 1.

  5. It is recommended that boars be kept in thin, thrifty condition so that they are able to breed gilts and sows. The weight of boars is controlled by the amount of daily feed. In some cases this may vary from 2–6 lb per day.

Table 1. 

Maximum number of services per boar.

 

Hand Mating

Pen Mating

Per Month

Boar

Per Day

Per Week

Per Month

Mature Boar

2

10

40

25

Junior Boar

1

7

25

18

Systems of Breeding

There is no one best system of breeding or secret of success for any and all conditions. Each breeding program is an individual case. The choice of the system of breeding should be determined primarily by the size and quality of the herd, equipment available, finances and skill of the producer, and by their ultimate goal.

Purebreeding

A purebred animal is defined as a member of a breed which possesses a common ancestry and distinctive characteristics and is either registered or eligible for registration in that breed. Purebreeding is the mating of two purebred animals of the same breed. The purebred producer has the responsibility of producing genetically superior animals for the commercial producer.

Inbreeding

Inbreeding is the system of breeding in which closely related animals are mated. This includes (1) sire to daughter, (2) son to dam, and (3) brother to sister. Inbreeding is suggested for only highly qualified operators who are making an effort to stabilize important traits in a given set of animals. Intensive selection is needed to reduce the risk of producing undesirable traits in breeding stock when inbreeding is practiced.

Linebreeding

Linebreeding is a system of breeding in which the degree of relationship is less intense than in inbreeding and is usually directed towards keeping the offspring related to some highly prized ancestor. The degree of relationship is not closer than half-brother half-sister matings or cousin matings, etc. Linebreeding is practiced to conserve desirable traits of an outstanding boar or sow line.

Outcrossing

Outcrossing is the mating of animals of the same breed but which have no closer relationship than at least 4–6 generations. This is the general system that is practiced by most purebred breeders and is classified as a safe system in the purebred business.

Crossbreeding

Crossbreeding is the mating of two animals which are members of different breeds. This system is being practiced by the majority of commercial swine producers because of the resulting hybrid vigor that makes possible improved production efficiency. Table 2 lists the expected advantages of crossbreds over purebreds.

Table 2. 

Expected advantage of crossbreds over purebreds.

 

First Cross

Multiple Cross

Boars

Purebred

Purebred

Sows

Purebred

Crossbred

Pigs

Crossbred

Crossbred

Litter size at farrowing

0%

5%

Survival

7%

12%

Litter size at weaning

10%

20%

Weight of ind. pigs at 154 days

11%

14%

Total litter wt. at 154 days

22%

30%

N.C.S.U. Experiment Station Bulletin 432, May 1967

Crisscrossing or two breed rotation—Boars of two different breeds are used in alternate generations. Crossbred sows resulting from this mating are bred back to the breed of the grandsire on the dam side. An example would be cross a Hampshire x Yorkshire sow, Yorkshire boar x crossbred Hampshire x York sow, Hampshire boar x crossbred Yorkshire x Hampshire sows, etc.

Another system of crisscrossing that might be followed would be Hampshire boar x Yorkshire sows—breed 1/2 Hamp 1/2 York sows to another Hamp boar producing 3/4 Hamp gilts which are crossed back to York boars. Boar rotation in this system—2 Hamps 1 York.

Three breed rotation or triple crossing—This system involves the use of boars of several breeds attempting to capitalize on the strong traits within each breed. An illustration: Hampshire x Yorkshire producing crossbred Hampshire x York gilts crossed with a Duroc boar. The three way cross gilt in turn would be crossed back to a Yorkshire boar and then repeat the system. The attempt here is to capitalize on the muscling traits of the Hampshire, mothering ability of the York and the growth ability of the Duroc or any such combination of breeds which suits the producer's need.

Breeding Program

Hand or individual mating of boars, sows, and gilts is recommended over field mating where feasible. If pasture mating is practiced, it is recommended that the following be done:

  1. Divide the sow or gilt herd so as to have one boar per group.

  2. Alternate boars in the sow or gilt herd. Use one boar or set of boars one day and another boar or set of boars the next day.

  3. Boars of the same size and age that were housed together while mating sows can continue to be housed together during the off season. Boars of different ages should not be housed together. Holding lots for boars should be constructed out of strong material that will restrain the animal adequately. Build pens narrow and long. To encourage exercise, feed at one end and water at the other. Furnish adequate shade and shelter for inclement weather.

  4. It is recommended that gilts and sows be kept separate during the gestation period.

  5. Sows and gilts should be hand-fed. Feeding can be controlled by:

    • feeding commercial cubes or shelled corn and supplement scattered out over the pasture to prevent boss sows from getting more than their share and,

    • furnishing individual feeding stalls for greater control.

Note: The use of individual feeding stalls offers the best opportunity for:

  1. Feeding each sow or gilt to meet their needs.

  2. Elimination of "boss sow" effects.

  3. Reduction in feed wastage.

  4. Close observation of individual animals.

If pasture is used, allow 10 to 12 gilts or 8 to 10 sows per acre on good pasture such as millet in summer, and oats, rye, wheat, or lupines in winter.

Tables

Table 3. 

Swine gestation table (115 Days), if bred Jan. 1–April 30.

If Bred

Will Farrow

If Bred

Will Farrow

If Bred

Will Farrow

If Bred

Will Farrow

Jan 1

Apr 26

Feb 1

May 27

Mar 1

Jun 24

Apr 1

Jul 25

Jan 2

Apr 27

Feb 2

May 28

Mar 2

Jun 25

Apr 2

Jul 26

Jan 3

Apr 28

Feb 3

May 29

Mar 3

Jun 26

Apr 3

Jul 27

Jan 4

Apr 29

Feb 4

May 30

Mar 4

Jun 27

Apr 4

Jul 28

Jan 5

Apr 30

Feb 5

May 31

Mar 5

Jun 28

Apr 5

Jul 29

Jan 6

May 1

Feb 6

Jun 1

Mar 6

Jun 29

Apr 6

Jul 30

Jan 7

May 2

Feb 7

Jun 2

Mar 7

Jun 30

Apr 7

Jul 31

Jan 8

May 3

Feb 8

Jun 3

Mar 8

Jul 1

Apr 8

Aug 1

Jan 9

May 4

Feb 9

Jun 4

Mar 9

Jul 2

Apr 9

Aug 2

Jan 10

May 5

Feb 10

Jun 5

Mar 10

Jul 3

Apr 10

Aug 3

Jan 11

May 6

Feb 11

Jun 6

Mar 11

Jul 4

Apr 11

Aug 4

Jan 12

May 7

Feb 12

Jun 7

Mar 12

Jul 5

Apr 12

Aug 5

Jan 13

May 8

Feb 13

Jun 8

Mar 13

Jul 6

Apr 13

Aug 6

Jan 14

May 9

Feb 14

Jun 9

Mar 14

Jul 7

Apr 14

Aug 7

Jan 15

May 10

Feb 15

Jun 10

Mar 15

Jul 8

Apr 15

Aug 8

Jan 16

May 11

Feb 16

Jun 11

Mar 16

Jul 9

Apr 16

Aug 9

Jan 17

May 12

Feb 17

Jun 12

Mar 17

Jul 10

Apr 17

Aug 10

Jan 18

May 13

Feb 18

Jun 13

Mar 18

Jul 11

Apr 18

Aug 11

Jan 19

May 14

Feb 19

Jun 14

Mar 19

Jul 12

Apr 19

Aug 12

Jan 20

May 15

Feb 20

Jun 15

Mar 20

Jul 13

Apr 20

Aug 13

Jan 21

May 16

Feb 21

Jun 16

Mar 21

Jul 14

Apr 21

Aug 14

Jan 22

May 17

Feb 22

Jun 17

Mar 22

Jul 15

Apr 22

Aug 15

Jan 23

May 18

Feb 23

Jun 18

Mar 23

Jul 16

Apr 23

Aug 16

Jan 24

May 19

Feb 24

Jun 19

Mar 24

Jul 17

Apr 24

Aug 17

Jan 25

May 20

Feb 25

Jun 20

Mar 25

Jul 18

Apr 25

Aug 18

Jan 26

May 21

Feb 26

Jun 21

Mar 26

Jul 19

Apr 26

Aug 19

Jan 27

May 22

Feb 27

Jun 22

Mar 27

Jul 20

Apr 27

Aug 20

Jan 28

May 23

Feb 28

Jun 23

Mar 28

Jul 21

Apr 28

Aug 21

Jan 29

May 24

----

----

Mar 29

Jul 22

Apr 29

Aug 22

Jan 30

May 25

----

----

Mar 30

Jul 23

Apr 30

Aug 23

Jan 31

May 26

----

----

Mar 31

Jul 24

----

----

Table 4. 

Swine gestation table (115 Days), if bred May 1–August 31.

If Bred

Will Farrow

If Bred

Will Farrow

If Bred

Will Farrow

If Bred

Will Farrow

May 1

Aug 24

Jun 1

Sep 24

Jul 1

Oct 24

Aug 1

Nov 24

May 2

Aug 25

Jun 2

Sep 25

Jul 2

Oct 25

Aug 2

Nov 25

May 3

Aug 26

Jun 3

Sep 26

Jul 3

Oct 26

Aug 3

Nov 26

May 4

Aug 27

Jun 4

Sep 27

Jul 4

Oct 37

Aug 4

Nov 27

May 5

Aug 28

Jun 5

Sep 28

Jul 5

Oct 28

Aug 5

Nov 28

May 6

Aug 29

Jun 6

Sep 29

Jul 6

Oct 29

Aug 6

Nov 29

May 7

Aug 30

Jun 7

Sep 30

Jul 7

Oct 30

Aug 7

Nov 30

May 8

Aug 31

Jun 8

Oct 1

Jul 8

Oct 31

Aug 8

Dec 1

May 9

Sep 1

Jun 9

Oct 2

Jul 9

Nov 1

Aug 9

Dec 2

May 10

Sep 2

Jun 10

Oct 3

Jul 10

Nov 2

Aug 10

Dec 3

May 11

Sep 3

Jun 11

Oct 4

Jul 11

Nov 3

Aug 11

Dec 4

May 12

Sep 4

Jun 12

Oct 5

Jul 12

Nov 4

Aug 12

Dec 5

May 13

Sep 5

Jun 13

Oct 6

Jul 13

Nov 5

Aug 13

Dec 6

May 14

Sep 6

Jun 14

Oct 7

Jul 14

Nov 6

Aug 14

Dec 7

May 15

Sep 7

Jun 15

Oct 8

Jul 15

Nov 7

Aug 15

Dec 8

May 16

Sep 8

Jun 16

Oct 9

Jul 16

Nov 8

Aug 16

Dec 9

May 17

Sep 9

Jun 17

Oct 10

Jul 17

Nov 9

Aug 17

Dec 10

May 18

Sep 10

Jun 18

Oct 11

Jul 18

Nov 10

Aug 18

Dec 11

May 19

Sep 11

Jun 19

Oct 12

Jul 19

Nov 11

Aug 19

Dec 12

May 20

Sep 12

Jun 20

Oct 13

Jul 20

Nov 12

Aug 20

Dec 13

May 21

Sep 13

Jun 21

Oct 14

Jul 21

Nov 13

Aug 21

Dec 14

May 22

Sep 14

Jun 22

Oct 15

Jul 22

Nov 14

Aug 22

Dec 15

May 23

Sep 15

Jun 23

Oct 16

Jul 23

Nov 15

Aug 23

Dec 16

May 24

Sep 16

Jun 24

Oct 17

Jul 24

Nov 16

Aug 24

Dec 17

May 25

Sep 17

Jun 25

Oct 18

Jul 25

Nov 17

Aug 25

Dec 18

May 26

Sep 18

Jun 26

Oct 19

Jul 26

Nov 18

Aug 26

Dec 19

May 27

Sep 19

Jun 27

Oct 20

Jul 27

Nov 19

Aug 27

Dec 20

May 28

Sep 20

Jun 28

Oct 21

Jul 28

Nov 20

Aug 28

Dec 21

May 29

Sep 21

Jun 29

Oct 22

Jul 29

Nov 21

Aug 29

Dec 22

May 30

Sep 22

Jun 30

Oct 23

Jul 30

Nov 22

Aug 30

Dec 23

May 31

Sep 23

----

----

Jul 31

Nov 23

Aug 31

Dec 24

Table 5. 

Swine gestation table (115 Days), if bred September 1–December 31.

If Bred

Will Farrow

If Bred

Will Farrow

If Bred

Will Farrow

If Bred

Will Farrow

Sep 1

Dec 25

Oct 1

Jan 24

Nov 1

Feb 24

Dec 1

Mar 26

Sep 2

Dec 26

Oct 2

Jan 25

Nov 2

Feb 25

Dec 2

Mar 27

Sep 3

Dec 27

Oct 3

Jan 26

Nov 3

Feb 26

Dec 3

Mar 28

Sep 4

Dec 28

Oct 4

Jan 27

Nov 4

Feb 27

Dec 4

Mar 29

Sep 5

Dec 29

Oct 5

Jan 28

Nov 5

Feb 28

Dec 5

Mar 30

Sep 6

Dec 30

Oct 6

Jan 29

Nov 6

Mar 1

Dec 6

Mar 31

Sep 7

Dec 31

Oct 7

Jan 30

Nov 7

Mar 2

Dec 7

Apr 1

Sep 8

Jan 1

Oct 8

Jan 31

Nov 8

Mar 3

Dec 8

Apr 2

Sep 9

Jan 2

Oct 9

Feb 1

Nov 9

Mar 4

Dec 9

Apr 3

Sep 10

Jan 3

Oct 10

Feb 2

Nov 10

Mar 5

Dec 10

Apr 4

Sep 11

Jan 4

Oct 11

Feb 3

Nov 11

Mar 6

Dec 11

Apr 5

Sep 12

Jan 5

Oct 12

Feb 4

Nov 12

Mar 7

Dec 12

Apr 6

Sep 13

Jan 6

Oct 13

Feb 5

Nov 13

Mar 8

Dec 13

Apr 7

Sep 14

Jan 7

Oct 14

Feb 6

Nov 14

Mar 9

Dec 14

Apr 8

Sep 15

Jan 8

Oct 15

Feb 7

Nov 15

Mar 10

Dec 15

Apr 9

Sep 16

Jan 9

Oct 16

Feb 8

Nov 16

Mar 11

Dec 16

Apr 10

Sep 17

Jan 10

Oct 17

Feb 9

Nov 17

Mar 12

Dec 17

Apr 11

Sep 18

Jan 11

Oct 18

Feb 10

Nov 18

Mar 13

Dec 18

Apr 12

Sep 19

Jan 12

Oct 19

Feb 11

Nov 19

Mar 14

Dec 19

Apr 13

Sep 20

Jan 13

Oct 20

Feb 12

Nov 20

Mar 15

Dec 20

Apr 14

Sep 21

Jan 14

Oct 21

Feb 13

Nov 21

Mar 16

Dec 21

Apr 15

Sep 22

Jan 15

Oct 22

Feb 14

Nov 22

Mar 17

Dec 22

Apr 16

Sep 23

Jan 16

Oct 23

Feb 15

Nov 23

Mar 18

Dec 23

Apr 17

Sep 24

Jan 17

Oct 24

Feb 16

Nov 24

Mar 19

Dec 24

Apr 18

Sep 25

Jan 18

Oct 25

Feb 17

Nov 25

Mar 20

Dec 25

Apr 19

Sep 26

Jan 19

Oct 26

Feb 18

Nov 26

Mar 21

Dec 26

Apr 20

Sep 27

Jan 20

Oct 27

Feb 19

Nov 27

Mar 22

Dec 27

Apr 21

Sep 28

Jan 21

Oct 28

Feb 20

Nov 28

Mar 23

Dec 28

Apr 22

Sep 29

Jan 22

Oct 29

Feb 21

Nov 29

Mar 24

Dec 29

Apr 23

Sep 30

Jan 23

Oct 30

Feb 22

Nov 30

Mar 25

Dec 30

Apr 24

----

----

Oct 31

Feb 23

----

----

Dec 31

Apr 25

Footnotes

1.

This document is RFAA083, one of a series of the Animal Sciences Department, UF/IFAS Extension. Original publication date December 1992. Revised August 2015. Visit the EDIS website at http://edis.ifas.ufl.edu.

2.

Randy Walker, former Extension swine specialist, UF/IFAS Extension, Gainesville, FL, 32611.


The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.