Understanding the reproductive cycle of domestic livestock, such as the pig, is foundational to responsible animal husbandry. The process by which a female pig, or sow, delivers her litter requires a specific term and careful observation. Recognizing the signs and stages of birth is important for ensuring the health and survival of both the mother and the newborns. This process is characterized by distinct phases, from behavioral changes preceding labor to the period of delivery and immediate post-birth care.
Farrowing Defining the Term
The specific term used in agriculture to describe the process of a pig giving birth is “farrowing.” This word is derived from “farrow,” which historically referred to a litter of pigs, and is now used as a verb to describe the act of producing that litter. The term is used universally for any female pig, including a gilt (one that has not yet farrowed) or a sow (one that has had at least one litter).
Recognizing the Pre-Birth Indicators
The approach of farrowing is signaled by several distinct behavioral and physical changes in the sow, often beginning 12 to 24 hours before the actual delivery. A noticeable pre-birth indicator is “nesting behavior,” where the sow becomes restless and actively gathers available materials like straw or hay to create a comfortable, protective area. Sows may also frequently get up and lie down, pace, or paw at the ground as contractions begin, indicating abdominal discomfort.
A significant physical sign is the development of the mammary glands and the presence of milk. Colostrum, the first milk, can often be stripped from the teats 6 to 12 hours before farrowing begins, offering a reliable time estimate for the onset of labor. The sow’s respiration rate also increases, moving to over 60 breaths per minute as the process nears. The vulva may also appear swollen and reddened in the final days and hours before delivery.
The Stages and Timeline of Delivery
The actual delivery phase, characterized by muscular contractions, typically begins after the sow has settled onto her side. The total time for the delivery of an entire litter usually ranges from two to four hours, though this duration can vary based on the sow and litter size. Piglets are typically born at intervals of 15 to 20 minutes, though the time between individual births can range up to an hour.
The unique anatomy of the sow, with its two-horned uterus, means that piglets are often born alternately from each horn. Piglets can be delivered either head-first or tail-first, with both presentations considered normal and usually occurring without complication. Once the sow begins straining with visible abdominal contractions, the first piglet should appear within a short time frame.
Following the delivery of the last piglet, the final stage of farrowing involves the expulsion of the placenta, often called the afterbirth. This usually occurs as a single mass within one to two hours after the entire litter has been born. Monitoring the timely expulsion of the placenta is important, as its retention can lead to postpartum health issues for the sow.
Immediate Post-Farrowing Priorities
Once the farrowing process is complete, immediate attention shifts to the welfare of the newborn piglets and the recovery of the sow. The most important priority for the piglets is the consumption of colostrum, the antibody-rich first milk, which provides passive immunity against diseases. Piglets should be encouraged to nurse quickly, as their ability to absorb these antibodies diminishes rapidly within the first hours of life.
Maintaining a warm and dry environment for the newborns is also necessary, as piglets are highly susceptible to chilling. Newborns need an ambient temperature of 90 to 95°F for the first few days, which is achieved through heat lamps or mats, as the sow prefers a cooler temperature.
For the sow, post-farrowing care focuses on monitoring for complications and ensuring she begins eating and drinking to support her milk production. Encouraging the sow to stand and move briefly can stimulate her system and help prevent common issues like constipation.