CHAPTER 104 Postpartum Care of the Sow and Neonates
Swine production managers today find both personal and financial satisfaction in maintaining a comfortable and sanitary environment for the sows and pigs under their care. This requires the manager to be particularly attentive to the comfort of individual sows, which includes monitoring feed and water intake and environmental conditions. Profit and productivity depend on ensuring that piglets receive adequate colostrum and milk so that a large number of healthy pigs can be weaned from each sow that farrows.1
Ensuring that gestating gilts and sows are comfortable and adequately fed facilitates the farrowing event. The gestating sow should be fed to maintain good body condition without overconditioning (obesity). The gestation ration formulated for sows must be balanced to provide the daily nutrient requirement of sows as they progress through the stages of pregnancy. Gilt gestation rations should be optimized to provide adequate protein, energy, calcium, and phosphorus for growth of the gilt and her unborn litter.
Nutrient restriction is used to optimize weight gain in sows. Today’s National Research Council (NRC) requirements for gestational sows utilize many factors to consider weight gain.2 This weight gain is influenced by the gestating sow’s requirement for energy, maintenance, protein accretion, fat accretion, products of conception, and thermoregulation.
Amino acid requirements of gestating sows are influenced by their maintenance requirements, protein deposition in proteinaceous tissues, and protein deposition in the products of conception. Folic acid and biotin can be used to supplement gestation rations for increasing the number of liveborn pigs.
Use of gestation crates enhances body condition by allowing individual females to be fed according to their needs. Pen gestation can result in variable body condition when smaller females cannot compete for feed. These pigs lose weight, whereas dominant females tend toward obesity.
In some production systems, protection of neonatal pigs from infectious diseases (e.g., infection due to Clostridium spp. or Escherichia coli) is required. To this end, generally the pregnant females are vaccinated once at 4 to 6 weeks and again at 2 weeks before farrowing for neonatal diseases endemic to the herd. Protection from pathogens can be partially controlled by ensuring that piglets receive high levels of protective immunoglobulins from the colostrum of their dam.
Controlling external and internal parasites commonly involves treatment of the sow approximately 2 weeks before farrowing to prevent pigs from being infected by their dams and to avoid contamination of the farrowing crate with expelled parasite eggs or larvae. Gestating females need to be identified, and individual sow records should be located in close proximity to the sow. Good records will ensure that sows are moved to the farrowing room 1 to 3 days before parturition. Extremely high piglet mortality is observed when litters are born in the gestation barn. The typical gestation length ranges from 113 to 117 days in most herds.
Pig flow can become uneven when management abandons an all-in–all-out strategy, resulting in insufficient time to sanitize the farrowing room. Farrowing in the gestation barn may occur with increased frequency, especially if the number of sows farrowing is large.
All sows entering the farrowing house should be examined, with particular emphasis placed on the underline of the sow. Damaged mammary glands or inverted nipples should be noted and recorded, because this information can be utilized in making cross-fostering and culling decisions.
It is tentatively assumed in the absence of convincing data that sows should be washed with soap or mild detergent and water to remove pathogen-containing manure before entry into the farrowing house. This assumption, however, requires further testing.
The farrowing facility generally is the most costly facility of the production system and requires the greatest labor specialization. Therefore, many production systems will have less than 48 hours to clean rooms in between groups, even though a longer time between groups may reduce contamination by bacterial pathogens in the barn. Sanitation of the farrowing facilities is crucial to preventing neonatal pig scours. To minimize neonatal disease, farrowing facilities should be managed on an all-in–all-out basis to allow thorough cleaning, disinfecting, and drying between groups.
Using flooring that provides a high proportion of open space to solid space that is easy to keep clean and dry can minimize pathogen exposure.4 This flooring generally is made of cast iron or steel rods that may be coated. Plastic flooring also is used. Utilization of cast iron or steel flooring under the sow and plastic-coated wire or plastic flooring in the creep area can improve piglet comfort and decrease preweaning mortality by keeping the sow cool and piglets warm. Piglets will avoid being laid on by the sow by staying away from the “cool” sow flooring.
The number of sows that can be farrowed at any given time often limits the number of pigs produced. The number of pigs weaned per farrowing crate is a good measure of how a farrowing facility is being utilized. Farms weaning pigs before 21 days of age should have a goal of 140 pigs or more weaned per farrowing crate per year, or 9.5 weaned pigs per sow.5
Paying particular attention to the comfort of the sow at farrowing is paramount to the profitability of a production facility. Good animal husbandry skills are rewarded at this phase of production by increased sow survivability and employee satisfaction. Farrowing is a time of high risk for sows. It has been observed that 42% of sow deaths occur during the peripartum period, and an additional 16.5% of sow death loss occurs during lactation.6 During the peripartum period, sows are prone to specific disease conditions, such as mastitis and metritis, that may lead to lactation insufficiency. Heat stress is common in sows during the hot months of summer, resulting in a seasonal increase in death loss. Uterine prolapse in the sow is rare but often is fatal; it accounts for less than 7% of all sow death losses.6
As the sow begins parturition, she will become partially or completely anorectic for several hours before and after parturition. Respiratory rate will increase 30 to 80 minutes before parturition to 95 to 105 breaths per minute (normal 13 to 18 per minute) and rectal temperature has been observed to increase from 38.7° to 40.0° C 24 hours before farrowing. Pigs are usually born at 15-minute intervals. Intervention is recommended if the farrowing interval is longer than 1 hour between pigs. The most common cause of dystocia is uterine inertia; however, sows should be manually examined using a hygienic technique before any treatments are administered. Oxytocin can be administered at a dose of 5 to 10 IU every 2 to 4 hours to control uterine inertia after it is established that a piglet is not lodged in the birth canal. Larger doses of oxytocin can inhibit the desired effect.
When the sow stops straining and begins to demonstrate an interest in her litter, the farrowing attendant can assume that farrowing is complete. Complete expulsion of the fetal membranes and placentas is the final phase of parturition, however. The time required for expulsion of the fetal membranes may range from 20 minutes to 12 hours after the last pig is born. Retained placenta occurs rarely in sows. Failure to find the placentas in the farrowing crate 4 to 12 hours post partum suggests the presence of another pig in the birth canal, and a vaginal examination is indicated. Sows that continue to strain, have a malodorous and discolored vulvar discharge, or show signs of depression or weakness also should be vaginally examined for retained pigs.
Many sows are anorectic during parturition and may refuse to eat for the next 48 hours. Feed should be withheld from sows (or only a very small amount provided) the day of farrowing. Then feed can be increased to 4 pounds daily, plus 1 pound per pig per day for the first week, with an average intake of 10 to 12 pounds of feed per day. Water intake is essential for optimizing feed intake and milk production during lactation. Lactating sows will drink 4 to 5 gallons of water per day, and the recommended flow rate for nipple waterers is 2 quarts per minute.
The sow is continually available for suckling by the newborn pigs for the first few hours after parturition. This constant mammary stimulation results in a high level of circulating oxytocin and facilitates the piglet’s ability to readily obtain colostrum. The sow generally is exhausted from parturition and demonstrates little interest in the piglets. During this time, however, some sows are observed to savage their newborn pigs. This condition tends to occur more often in primiparous sows, and the aggressive behavior is often directed toward the first-born piglet. Separation of the piglets from the sow until farrowing is completed usually is all that is required to calm a sow that is savaging her piglets. On some occasions a sow may require sedation before accepting her piglets or fostered piglets. The sow’s udder should be inspected for color, consistency, heat, and lesions likely to be associated with pain at this time to determine if the sow is suffering from mastitis or any other puerperal disease condition.
Approximately 24 hours after birth the sow will begin to actively encourage the pigs to nurse by grunting and positioning her mammary glands so that the nipples are available for suckling. Cyclic nursing begins at this time, and milk letdown occurs approximately every hour for a period of a few minutes.