Techniques for detecting sows in heat and mating

For all pig breeds, never mate them during the first heat, because the pig's body is not fully developed, the number of eggs released during the first heat is small... if mated, the number of offspring will be small.

1. Estrous cycle in pigs

1.1. Age of first estrus in gilts

Different pig breeds have different ages of first heat.

Domestic pig breeds such as Mong Cai pigs first go into heat at 4 - 5 months old, weighing 30 - 40 kg.

Crossbred pigs with foreign breeds have a later age of first estrus than purebred pigs. Crossbred female pigs with foreign breeds such as F1 (Yorkshire x Mong Cai) and F1 (Landrace x Mong Cai) have their first estrus at 6 months of age, weighing 70 - 75 kg.

Foreign pig breeds usually have their first heat at 6-7 months, weighing 100-110 kg.

1.2. Estrous cycle in sows

The estrus cycle in sows is usually 21 days (ranging from 17 - 23 days). The estrus period usually lasts 3 - 4 days.

Sows will come back into heat about 4 - 6 days after weaning.

2. Techniques for detecting sows in heat

Detecting sows in heat is the most important step in breeding.

Sows should be checked at least twice a day, 12 hours apart. Estrus should be checked between 5-6am and 5-6pm, when pigs usually show the most obvious signs of estrus.

To accurately detect when a sow is in heat, it is necessary to understand the estrus cycle and carefully observe the sow's symptoms.

Signs of estrus in sows:

First day of estrus

Sows walk around, squeal, want to jump out of the pen; eat poorly or stop eating, destroy the trough; avoid or run away if touched. The vulva is swollen, pink, and shiny. The mucus flowing out of the vulva is thin, clear, and not sticky.

Second day of estrus

In the morning, the sow is quieter, less squealing, occasionally jumping on the back of another sow, but not standing still when another sow jumps on her back.

By afternoon, the vulva is less swollen, turns light pink, and has faint wrinkles. The mucus has turned into a sticky state. To determine if the pig is in heat (lethargic): use both hands to rub from the last row of udders up to the pig's back, then press on the pig's back (if there is a boar's face, that's even better). When the pig stands still, its ears are up, ready for the boar to mate. At this time, mating or insemination will give the best results.

Third day of estrus

The lethargy gradually subsided, and towards the end of the day, the pig no longer liked to be near the boar. The vagina gradually shrank back to normal, with less vaginal discharge, opaque white, and not sticky.

The tail covers the vulva.

3. Breeding techniques

3.1. First mating (mating gilts)

The necessary and sufficient condition for breeding gilts is that the pigs must be of sufficient age and weight.

The age for first mating for domestic sows is 7 - 7.5 months old and for crossbred (foreign x domestic) and foreign sows is 7.5 - 8 months old. Suitable weight for mating: Mong Cai pigs are 50 - 55 kg, crossbred pigs (Yorkshire/Landrace x Mong Cai) are 75 - 85 kg, foreign pigs are 110 - 130 kg.

For all pig breeds, never mate immediately during the first heat, because the pig's body is not fully developed, the number of eggs released during the first heat is small... if mated, the number of offspring will be small. Should mate when the gilt has gone through 2 or 3 heat cycles.

It is necessary to determine the exact time of lethargy in the gilts to mate them immediately. Then mate them a second time about 12 hours after the first mating.

It is necessary to record the mating date to predict the farrowing date.

3.2. Mating sows (pigs that have given birth from the second litter onwards)

Sows will return to heat 4-6 days after weaning. It is necessary to monitor, observe carefully and determine the exact time of lethargy in pigs to prepare for mating.

When detecting lethargy in sows, do not mate them immediately as with gilts, but mate them for the first time within 10 - 12 hours of detecting lethargy.

To make the sow give birth to many piglets, the second mating should be repeated about 10-12 hours after the first mating.

It is necessary to record the mating date to predict the farrowing date.

Direct breeding

Advantages: Easy to do, no need to invest in breeding equipment.

Disadvantages: It takes a lot of effort to transport boars, the possibility of disease transmission directly from boars to sows is high, cannot mate with many sows at the same time, cannot use good male breeders because of the large difference in weight between boars and sows.

Artificial insemination

Advantages: Sows will receive semen from selected good boars, no need to transport boars, no restrictions on pig size difference, one semen collection can be used to mate with many sows.

Disadvantages: Requires trained technicians and equipment for breeding.

Note: Boars used for artificial insemination must be healthy and have passed semen quality testing.

Artificial insemination technique

Intrauterine insemination technique

Semen must be well preserved in a cool place (about 20 degrees Celsius), away from light, and avoid shaking or shaking the vial. The vial must not be cracked or have bubbles. The steps for performing artificial insemination are as follows:

Prepare the insemination equipment, including: Tools (bottles, bags) to hold semen, insemination tubes and pressure device to push semen (pump ball or syringe). Boil the insemination equipment in boiling water for 15 minutes, drain, and let cool.

Clean the sow's vulva area, gently stroke the sow's back to keep her still. Apply vaseline to the sow's sperm duct and vulva.

Warm the semen to 35 - 37 degrees Celsius by holding the semen bottle in the palm of your hand for a while.

According to the National Agricultural Extension Center