The major goal for managing nutritional programs for sows in lactation is to maximize milk production without incurring substantial losses in body condition that impair subsequent reproductive performance.

The nutritional demands of the modern lactating sow and litter have changed greatly. Today's genetic advancements provide pigs with faster growth rates, better feed efficiencies and improved leanness.

However, these developments have created new challenges in feeding lactating sows, which generally have lower voluntary feed intake and are leaner with greater body size at maturity.

Likewise, today's piglets have increased growth potential such that even the most productive sows often fail to produce enough milk to meet their requirements for maximizing growth performance. These rapid changes make it important to continuously evaluate and develop sow nutritional programs that account for these changes to maximize both sow reproductive and litter performance.

It is well known that lactating sows need maximum intake of a good quality diet to optimize sow and litter performance. However, too often lactating sows are limited in feed intake, resulting in decreased milk production and excessive sow weight or backfat loss that can hurt future reproductive performance.

Therefore, the three main goals of the sow lactation nutrition program are: 1) maximize intake of a properly formulated diet; 2) match the amino acid and other nutrient levels to the level of feed intake that is achieved; and 3) maintain a reasonable feed cost/weaned pig.

Attitude is Key

It all begins with the right frame of mind and resolve. Many producers seem to accept that it is “normal” for sows to lose body condition during lactation. However, a number of producers have shown lactation weight loss can be prevented.

Some studies suggest up to 30-35 lb. weight loss won't negatively affect performance. Still, if we adopt the attitude that any amount of weight loss is unacceptable, then there is a greater chance that we will succeed.

Prepare for First Lactation

Sows have greater capacities to meet their nutritional needs due to their higher feed intake and larger body reserves compared to gilts. More problems are encountered with first- and second-litter sows due to their lower feed intakes, smaller body frames and less fat reserves. These lower reserves produce large gilt body condition losses after farrowing, resulting in lower subsequent litter size and longer wean-to-estrus intervals.

Poor fat reserves at first parity also leads to progressive decreases in body reserves that impact sow longevity.

Gilt pool nutrient management will help prevent this problem. Feed gilts to attain adequate body reserves of lean and fat prior to first mating. Research suggests that gilts should weigh at least 300 lb. and record at least one estrus to provide the body reserves and physiology to optimize lifetime reproductive performance.

Certainly, in addition to an adequate nutrition program, other critical management factors such as boar exposure and proper acclimation are important ingredients for successful gilt integration into the herd and to maximize lactation performance.

Start at Conception

Feeding sows for optimum lactation begins at conception, not after parturition. There is a strong, negative relationship between gestation feeding level and lactation feed intake, which is mediated by the female's backfat level at farrowing.

Using the equation, in Table 1, it is predicted that sows with 22 mm. (0.88 in.), 18 mm. (.72 in.) and 14 mm. (.56 in.) of backfat at farrowing will consume an average of 10.4, 11.6 and 12.7 lb. of feed/day during lactation, respectively. So reducing backfat by 4 mm. (0.16 in.) is projected to increase lactation feed intake by about 1 lb./day. Thus, the fatter the sow, the lower her feed consumption during lactation.

Body weight or fatness of each pregnant sow must be managed effectively. Feeding regimens during pregnancy must equally target the demands of lactation as well as the demands for fetal and maternal growth.

Kansas State University nutritionists have developed an objective method of feeding gestating sows based on an estimate of weight and backfat thickness (Table 1). An estimate of weight is obtained by taking a flank-to-flank measurement using a flexible measuring tape to categorize sows into body weight groups. Real-time ultrasound is then used to measure backfat as an objective measure of body condition.