Nutritional Requirements and Feeding Guidelines for Gestating Sows

[The period from mating and conception to farrowing is called gestation]

The basic tasks of feeding and managing gestating sows are: to ensure the normal development of fertilized eggs and fetuses in the mother's body, to prevent stillbirths and miscarriages, so as to obtain a large number of good-quality piglets; to ensure that sows are in good body condition during gestation, laying the foundation for lactation during the nursing period. In addition, first-time sows need superior feeding, as first-time sows require 23-30% nutrition to maintain their own growth and development.

1. Weight changes in gestating sows: During gestation, sows gain weight rapidly due to fetal growth and development, development of the uterus and other organs, and nutritional reserves for postpartum lactation.

2. Patterns of embryonic growth and development: Embryonic growth and development during gestation follows a pattern. In early gestation, embryos are very light and weight gain is slow; from 60 days onward, the rate of weight gain accelerates; from 90 days onward, fetal weight gain is very rapid, with about 60% of fetal body weight being gained during this period. During this period, nutrition must be increased to meet fetal growth and development needs.

3. Two critical periods: The first critical period is around 20 days after conception. This is when the fertilized eggs implant (implantation begins 12 days after conception and ends at 24 days) at different locations in the uterine horns and gradually form the placenta. Before the placenta is formed, embryos are susceptible to environmental conditions, and special care must be given in feeding and management. Attention must be paid to not feeding moldy feed or frozen feed, and not providing ice water. Mechanical stimulation such as kicking, beating, squeezing, pressing, and fighting must also be prevented to avoid high fever and miscarriage. During the first month of early gestation, comprehensive nutrition should be provided; at this time embryonic growth is relatively slow and no additional nutrition is needed. The second critical period is after 90 days of gestation. During this period, fetal growth and weight gain are particularly rapid. The sow's assimilation capacity is strong, and required nutrients increase significantly. In management, mechanical stimulation such as squeezing, pressing, and bumping must also be prevented, and rough driving is prohibited. Feeding frozen feed is strictly prohibited. Good fetus protection work must be done.

4. Feeding methods for gestating sows: The "coarse first, fine later" method is suitable for sows in relatively good body condition. From 1-84 days after conception, green and coarse feed is predominant; from 85-114 days in the later stage, concentrated feed is predominant. Feeding amounts: 1.8-2.3 kg in the early stage, and 2.5-3.0 kg in the later stage. The feeding amount may be appropriately increased or decreased according to the pig's body size.

5. Protein requirements: Generally about 13% of the daily ration, that is, feeding 156 g of crude protein per head per day can ensure normal fetal development. Since first-mated sows are still growing and developing themselves, their protein requirements are about 1/5 to 1/3 higher than those of adult gestating sows.

[Management Techniques]

Doing a good job of fetus protection and preventing mechanical miscarriage is very important in late gestation. At this time, caretakers must strengthen their sense of responsibility, provide patient care, and must never treat sows roughly. Prevent fighting, squeezing, and bumping. Provide appropriate exercise during mid-gestation (41-98 days), no exercise 7-10 days before farrowing, and no exercise for one month after mating.

1. The pen should be level, keeping warm in winter and cool in summer.

2. Maintain pig body hygiene and prevent parasites.

3. Ensure feed quality, do not feed moldy or frozen feed, and provide clean drinking water.

[Causes of Embryonic Death and Miscarriage in Gestating Sows]

1. Causes of embryonic death in gestating sows:

① Malnutrition. Sows severely lacking protein, vitamins A, E, B2, and minerals such as calcium, phosphorus, iron, selenium, and iodine during gestation. In addition, feeding too much concentrated feed with high carbohydrate content can also cause death.

② The contradiction between a high ovulation number and a small uterine volume. A high ovulation number means a high number of embryos, but uterine blood volume does not increase significantly, resulting in insufficient nutrient supply and embryonic death.

③ Endocrine insufficiency. Insufficient progesterone secretion in sows during gestation causes embryonic death.

④ Suffering from reproductive tract diseases. Sow uteri infected with Brucella, Escherichia coli, hemolytic Staphylococcus, Pasteurella, etc.

⑤ Suffering from high-fever diseases such as swine fever, swine erysipelas, Japanese encephalitis, influenza, septicemia, etc. Continuous high fever for several days, with body temperature reaching 41°C, causes miscarriage.

⑥ Feed or pesticide poisoning can also cause embryonic death.

⑦ Effects of high temperature.

⑧ Mating too early or too late.

2. Causes of miscarriage in sows:

① Malnutrition. Severe deficiency of protein, vitamins, and minerals in the daily ration.

② Overly fat or overly thin.

③ Highly inbred mating between boars and sows, reducing embryonic vitality.

④ Moldy feed.

⑤ Feeding frozen feed or ice water in winter or early spring.

⑥ Injection of vaccines with strong reactions during gestation or suffering severe stress.

⑦ Suffering from reproductive disorder diseases such as Japanese encephalitis, parvovirus disease, pseudorabies, etc.

[Methods for Calculating the Expected Farrowing Date]

After mating, keep good mating records as well as the breed and ear number of the boar used for mating. The gestation period is 110-120 days, with an average of 114 days. Calculation methods:

1. The three-three-three method: that is, three months, three weeks, and three days.

2. The method of adding three to the mating month and adding 20 to the day: that is, add 3 to the month and add 20 days to the mating day.