For newborn piglets, sow milk is the sole source of nutrition, providing everything needed for survival and rapid growth. This diet is tailored to the demands of young pigs, who are born with limited energy reserves and an immature immune system. A sow’s ability to produce this complete food source is a determining factor in the health of her entire litter.
Nutritional Profile of Sow Milk
Sow milk is an energy-dense fluid formulated to support the accelerated growth rates of piglets. Its composition is not static, transforming from colostrum to mature milk within the first few days of a piglet’s life. This change reflects the evolving needs of the growing piglet, shifting from immune support to providing energy for growth. The unique properties of sow milk make it difficult to replicate.
The initial secretion available for the first 24 to 36 hours is colostrum. This “first milk” is less a source of energy and more a vehicle for passive immunity, as piglets are born without their own protective antibodies. Colostrum is rich in maternal immunoglobulins, particularly IgG, which are absorbed directly into the piglet’s bloodstream for immediate protection. Concentrations of these proteins are highest in the first few hours after birth and decline rapidly.
Following the colostral period, the milk’s composition changes to mature milk. The concentration of immunoglobulins decreases, while the levels of fat, lactose, and total solids increase to fuel rapid weight gain. Mature sow milk contains about 6-8% fat, a high level that delivers the calories piglets need. Compared to cow’s milk, sow milk is considerably richer in fat and protein, making cow’s milk an inadequate substitute without significant modification.
Sow Lactation and Production Cycle
The process of milk production in a sow, or lactation, follows a pattern tailored to the demands of a growing litter. In commercial farming, the lactation period lasts between 21 and 28 days, after which the piglets are weaned. Producing enough milk to sustain a large litter places significant metabolic demands on the sow. Her ability to meet this demand is influenced by several biological and environmental factors.
Milk production begins at a modest level after farrowing and increases substantially, reaching its peak around the third week of lactation. A modern sow can produce 10 to 12 kilograms of milk per day at her peak. This yield is driven by the suckling stimulus of the piglets; a larger litter will demand more milk, prompting the sow to produce more. After this peak, milk yield gradually declines until the piglets are weaned.
Genetics play a role, with some breeds selected for higher milk yields. The sow’s own nutritional intake, particularly of water, protein, and energy, is a major determinant of her output. Sows must consume enough to support their own bodily functions and synthesize large volumes of nutrient-rich milk, often mobilizing their own body reserves to do so.
Managing Sow Milk Insufficiency
Occasionally, a sow may fail to produce enough milk, a condition that can have consequences for her litter. This insufficiency can range from reduced milk production to a complete failure to produce milk. Recognizing the signs of a milk shortage early is important for survival. Piglets not receiving enough milk will appear gaunt, feel cold from lack of energy, and may squeal constantly from hunger.
When a sow is unable to adequately feed her piglets, a management technique is cross-fostering. This involves moving piglets from a large litter to a sow with a smaller litter and more available teats. This strategy is most effective if done within the first 24 to 48 hours after birth. This timing allows piglets to receive colostrum from their biological mother before being moved, ensuring they acquire maternal antibodies.
In situations where a foster sow is not available, a sow milk replacer can be used. These commercially available formulas are designed to mimic the high-fat, high-protein profile of natural sow milk. They can be provided as a supplement or as a complete nutritional source for orphaned piglets. When using milk replacers, maintaining strict hygiene during preparation and feeding is important to prevent digestive upset and illness.