Key Technical Points for Feeding and Management of Farrowing Sows

1. Pre-farrowing preparations

The gestation period of sows is generally around 110-120 days. During this stage, observation of the sows should be strengthened, and the following preparations for farrowing assistance should be made. First, choose a suitable place for the sow to give birth, then one week before the sow enters the pen, carefully clean and disinfect the farrowing house, and spread soft bedding straw. When farrowing in winter and spring, check the warming facilities of the pig house; in summer and autumn, check the heat protection and ventilation conditions inside the house.

A few days before farrowing, clean the sow's body and then disinfect it. Use 0.1% potassium permanganate solution to wash the teats and udder, and the vulva; wipe the sow's body with 2% lysol. Then drive the sow into the pen, and prepare farrowing tools, such as ear notching pliers, tooth clipping pliers, weighing equipment and farrowing records, petroleum jelly (for use during farrowing) and ligature thread (for umbilical cord cutting), etc. In addition, prepare disinfectants such as iodine tincture, alcohol, and potassium permanganate, and arrange duty personnel.

2. Signs of approaching farrowing

From 3-5 days before farrowing, the udder becomes swollen, glossy, hot, red, shiny, and enlarged; the teats on both sides swell outward into a "V" shape, and a small amount of thin milk can be squeezed out. One day and night or a few hours before farrowing, most sows' front-row teats can be squeezed or leak slightly yellowish, relatively sticky colostrum. If milk can be squeezed from the last pair of teats, farrowing will likely occur in about 6 hours. The vagina becomes relaxed, red and swollen, and the areas on both sides of the tail base gradually sink, though the sinking is often not obvious in fatter sows. The sow carries straw to make a nest. If the sow is restless, getting up and lying down, pacing around, with respiratory rate increasing from about 25 to 75 breaths per minute, the tail base raised, sometimes frequent urination, and labor pains begin, with mucus flowing from the vulva - the amniotic fluid "water breaking" - and the tail wagging, it indicates that farrowing is imminent.

3. Farrowing assistance

Farrowing in sows is accomplished through contractions of the uterus and abdominal muscles, which expel the fetus and fetal membranes. The sow lies on her side with limbs extended, the muscles of the hindquarters relaxed, and the sacrum and caudal vertebrae easily move upward, facilitating the passage of the fetus. Because the abdominal wall does not bear the weight of the fetus and internal organs, contraction of the abdominal muscles can make straining more forceful. The sow's pelvic axis slopes backward and downward, making the birth canal approximately a straight line, and combined with the fetus

being narrower at its widest point than the pelvis, the fetus is easily expelled, and dystocia rarely occurs. The duration of farrowing in sows varies depending on breed, age, number of fetuses, and the interval between fetal expulsions, usually 2 hours, and generally the first piglet is expelled more slowly. During farrowing assistance, first of all, there should be a quiet environment, which helps the sow's cerebral cortex receive stimuli from the uterus and send strong signals to promote smooth expulsion of the fetus. After the piglet is born, immediately use a cloth or soft straw to clear the mucus from the piglet's mouth and nose to ensure unobstructed breathing; wipe the whole body dry to promote rapid drying of the piglet's body surface, reduce body heat loss, and prevent colds. In addition, farrowing assistance tasks such as umbilical cord cutting, tooth clipping, and tail docking also need to be carried out.

4. Postpartum care

For newborn piglets, they should be allowed to suckle the sow's colostrum as soon as possible, which helps restore the piglet's body temperature, accelerate the sow's farrowing, and increase the affinity between the sow and piglets. For sows that farrow quietly, the method of suckling while giving birth can be adopted; for sows that do not farrow quietly, it is better to adopt the method of suckling after farrowing is completed. The temperature of the farrowing house does not meet the requirements of piglets, so heat dissipation and warming measures should be taken where the piglets lie down, to provide newborn piglets with a suitable ambient temperature (29-35°C). About 30 minutes after the sow finishes farrowing, the fetal membranes can be expelled, though some sows need a little longer. If the expelled fetal membranes are missing two uterine horns or are too small in weight, attention should be paid to preventing endometritis caused by retained fetal membranes. In addition, a large amount of fresh drinking water should be provided in a timely manner; clean the bedding straw contaminated with blood and mucus, and replace it with new straw; remove the fetal membranes, umbilical cords, and dead piglets, and do not let the sow eat them, to prevent the development of the vice of eating piglets.

5. Suitable temperature

Unsuitable temperature is another important factor causing reduced feed intake. Studies have shown that for lactating sows to achieve maximum feed intake, the farrowing house must maintain a moderate temperature (15-18°C). For every 1°C increase in the ambient temperature of the farrowing house, feed intake can decrease by 180 grams/day.