Breeding and Selection of Breeding Stock
Selecting high-quality breeding stock is essential for a productive and efficient pig farming operation. It is advisable to purchase breeding animals from reputable and preferably registered breeders who maintain proper records.
Selection of Breeding Gilts
Breeding gilts (young female pigs) should be carefully chosen to ensure the production of large, healthy litters. Ideal gilts should have at least 12 well-developed teats to accommodate a large litter. They should come from sows known for weaning 9-10 piglets and demonstrating good maternal instincts. Selection should begin at the weaning period, with further assessments conducted at 5-6 months of age.
Fast-growing weaners are preferred, as they tend to consume less feed per unit of live weight gain, reducing production costs. Additionally, gilts should possess good body conformation, including strong legs, sound feet, well-developed hams, and relatively light heads.
Selection of Breeding Boars
A high-quality boar significantly influences the herd's productivity since it contributes half the genetic traits. Selected boars should be free from defects, have sound feet, full hams, a uniform curve at the back, and an overall good length. To pass on favorable traits, a boar should also have at least 12 properly placed rudimentary teats.
Efficient boars are those that grow faster than the breed average, have lower back fat, and require less feed to reach a specific weight. A good boar should achieve 90 kg (198 lb) live weight before reaching four to five months old. To ensure adaptability and prevent disease transmission, boars should be purchased at least four to five weeks before their first use, allowing them time for quarantine and acclimatization.
Management of Breeding Stock
A successful pig farm relies on good-quality breeding animals sourced from farms with high hygiene and management standards. When purchasing breeding stock, it is beneficial to seek assistance from an experienced individual.
For boars, it is recommended to buy purebred individuals from reputable breeders who maintain records of their performance and lineage. Landrace and Large White breeds are commonly preferred. In the case of gilts, crossbreeding is a viable option, such as using Landrace or Large White sows crossed with boars of another breed. If selecting gilts for breeding, strict selection measures must be applied, with accurate records maintained on growth and feed conversion. If a proper record system is unavailable, it may be advisable to purchase replacement gilts.
To maintain consistency in breeding quality, gilts should ideally be purchased from the same breeder, following a structured breeding plan. Consultation with an adviser may be beneficial in establishing an effective breeding strategy.
Boar Management and Use
Training and Use of Young Boars
Young boars require careful supervision during their initial breeding experiences to prevent injuries and identify any reproductive issues. They should be at least eight months old before their first service, and ideally, they should mate with a sow of similar size.
Boars should be introduced to their mating pen a few minutes before the sow arrives to help them adjust to the environment. The pen should be free of obstructions and not have a slippery floor. A small sow, rather than a gilt, should be used for the boar’s first service.
Once a boar starts mating, its usage should be controlled. Young boars should not be used more than twice a week until they are one year old, while mature boars can be used up to three times a week, preferably not on consecutive days. Farms with 20 breeding sows should maintain at least two boars, a younger one for gilts and a mature boar for older sows. Keeping a spare boar is also advisable.
Replacement of Boars
Boars must be replaced when they become too large to serve most of the sows on the farm. Typically, a boar’s maximum working life ranges from 18 to 24 months, meaning they should be replaced when they reach 30 to 36 months of age. Maintaining breeding records is crucial to identifying infertile boars early.
Low libido can also be a concern, as some boars may be slow or reluctant breeders. Close monitoring is necessary, and underperforming boars should be replaced when needed.
Gilt Selection and Management
Breeding gilts should be chosen based on their ability to produce large litters with above-average growth rates and carcasses with low fat content. Ideal gilts have strong, straight legs, large and evenly sized claws, and a well-formed vulva. Their teats should be well-developed, evenly spaced, and positioned to allow adequate piglet suckling.
Gilts are usually selected for breeding at five to six months of age but should not be mated until they reach seven to eight months and weigh between 100 and 130 kg (220-287 lb). They must be in optimal condition, neither too fat nor too thin, to ensure a successful pregnancy and a large litter. Double or triple mating during standing heat is recommended for better conception rates. The effective reproductive life of a sow typically lasts four to five years.
Methods of Breeding
Natural Mating
This is the most commonly used method in pig breeding, offering high fertility and conception rates due to better heat detection, more accurate timing, and prolonged semen viability. However, natural mating has some disadvantages, including the risk of venereal diseases, the cost of maintaining boars, and the need for frequent boar replacements to avoid inbreeding.
Artificial Insemination (AI)
AI provides an alternative to natural mating, involving the placement of boar semen into the sow using specialized equipment. Successful AI requires effective heat detection, the availability of an inseminator during the heat period, and synchronization of heat cycles among sows (flushing).
One of the key advantages of AI is the reduced transmission of venereal diseases. However, knowledge of the sow’s heat cycle is crucial, as ovulation occurs after approximately 70% of the heat period has elapsed. It is recommended to inseminate 24 hours before ovulation for optimal results.
Materials required for AI include a pistolet, thaw monitors, a flask, sheaths, AI gloves, nitrogen, semen straws, and hormones.
Heat Detection and Pregnancy Confirmation
A sow’s heat cycle typically lasts 21 days, with heat signs divided into three stages:
- Early Heat Signs: Restlessness, swollen and reddish vulva, and white mucus discharge.
- Service Period (Standing Heat): The sow stands still when pressure is applied to her back, the vulva becomes less swollen, and slimy mucus is discharged. This is the optimal time for mating.
- Post-Heat Period: The sow no longer stands still when pressure is applied, and the vulva returns to normal size.
To stimulate regular heat, the sow should be weaned early (at five weeks) and moved to a house with dry sows. Direct contact with a boar (hearing, seeing, and smelling) can also stimulate heat. Feeding strategies, such as increasing feed intake (flushing) for up to ten days, can further enhance heat cycles.
Pregnancy can be confirmed by observing whether the sow returns to heat after 21 days. Additionally, after two months of pregnancy, the udder begins to develop, becoming firmer in the last two weeks before farrowing. The expected birth date is typically 115 days after service (three months, three weeks, and three days).
Culling of Breeding Stock
Sows that have difficulty conceiving or produce small litters should be culled, particularly after three unsuccessful mating attempts. Sows that fail to exhibit heat or produce fewer than seven piglets should also be removed from the herd. Generally, sows are culled after seven farrowings unless they continue to perform well.
Boars that exhibit infertility or low libido should also be culled, as they negatively impact herd productivity.
References
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