Gestating sows have different nutritional requirements as they go through pregnancy, but all too often, pork producers don’t make the necessary adjustments.

So says Ron Ball, a retired professor from the University of Alberta, in an address at the Midwest Swine Nutrition Conference held in mid-September in Indianapolis, IN. He presented research about the amino acid requirements during the different phases of gestation.

Intensive genetic selection has changed the underlying biochemistry and metabolism of the pig, Ball says. This process has resulted in increased heat production, increased rate of protein turnover, and increased energy and amino acid requirements.

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“We’re living with greater-costing sow herds than we need to,” he says. “That’s because our knowledge of sow nutrition has not kept pace with the rate of changes in sow productivity.”

There’s little fetal growth until about 70 or 80 days of gestation, when the fetal protein requirements increase tenfold, starting at 20 grams and moving to more than 200 grams, research shows.

In terms of amino acid requirements, lysine and threonine increase from early gestation to late gestation.

“The key message here is, because those requirements are so different, you cannot take the same diet you fed in early gestation and feed more of it in late gestation to meet those requirements without a whole lot of waste,” Ball says. “You need a second diet if you are really going to meet the requirements properly without overfeeding.”

According to Ball, there are three solutions to consider to meet the nutritional needs of pregnant sows:

The optimal solution is to use parity-segregated phase feeding. Formulate two diets. One diet should meet the minimum requirements of sows during gestation, and the other diet should meet the maximum requirements. Each sow should receive a blend of the two feeds that meets her specific nutritional needs. This approach works best for hog operations that use electronic sow feeders (ESF), with two feed lines.

The second-best solution is to formulate a “low diet” and a “high diet.” The low diet should be fed during early gestation. Around Day 85 of gestation, the sows should be fed the high diet to minimize overfeeding and underfeeding.

The third possible solution is to feed a low diet, and then topdress the sow diet with some extra feed for sows in late gestation.

Following one of these management options to supply the correct amount of nutrients for pregnant sows results in better body condition when entering lactation, better rebreeding success after the first litter, increased sow longevity and reduced feed costs — to the tune of almost $10/sow/year.

“We need to make the effort and the investment to change our feeding programs for sows,” Ball says.

Ball’s presentation was excerpted from the American Society of Animal Science Taking Stock e-newsletter found at takingstock.asas.org