Gilt Development Program Improves Sow Performance

Early attention to gilt development pays dividends. To ensure that a sow becomes a productive member of the breeding herd requires close attention to detail as soon as future replacement stock is weaned from their dam, says Laura Greiner, director of research at Innovative Swine Solutions, LLC, a division of Carthage (IL) Veterinary Service, Ltd. Gilts must be acclimated to the farm, and provided

Joe Vansickle, Senior Editor

February 15, 2010

11 Min Read
Gilt Development Program Improves Sow Performance

Early attention to gilt development pays dividends.

To ensure that a sow becomes a productive member of the breeding herd requires close attention to detail as soon as future replacement stock is weaned from their dam, says Laura Greiner, director of research at Innovative Swine Solutions, LLC, a division of Carthage (IL) Veterinary Service, Ltd.

Gilts must be acclimated to the farm, and provided diets higher in calcium and phosphorus than grower pigs in order to help bone mineralization and soundness. They should also be raised in an environment that gives adequate space — 10-12 sq. ft./gilt after 150 days of age.

Late gilt developer diets (220-250 lb.) should include about 0.65% total ileal digestible (TID) lysine, and consideration should be given to feeding organic trace minerals and additional vitamin E and biotin to help with hoof development and immune function, says Greiner. Pyroxidine (vitamin B6) and folic acid are also beneficial for embryo survivability and reproductive performance.

Greiner's stance is that gilts should be serviced at approximately 300 lb. and be on their second or third estrous cycle. Research suggests that if gilts are bred by 314 lb., retention through three parities is 68.8% of the gilt pool. Servicing at a heavier initial weight increases feed costs to maintain that body weight and may have a negative effect on structure, she attests.

Sow Condition in Gestation

Once in gestation, sows and gilts should be fed according to body condition determined by a Renco backfat measurement or visual appraisal.

“I am in favor of doing a visual scoring evaluation in the breeding stall. One of the reasons is that when comparing sows of similar visual body condition, one sow may be a leaner, more heavily muscled animal (backfat at 0.56-0.60 in.), while the other may be a thicker animal with less muscle and more backfat (0.64 in. and higher). When using backfat as the single measurement, we may overfeed the leaner animal to try to get her to a set backfat level. This can be a costly mistake. If she has good body condition, but a lower backfat measurement (0.52-0.60 in.), she will still do well.

“She will be a more aggressive eater in lactation compared to the second sow in the example that has less muscle and more backfat. The more feed the heavier-muscled sow is given in gestation to get her to a heavier backfat, the more she will add to her frame, costing the producer higher lifetime feed costs to feed the heavier/bigger sow,” Greiner says.

To accomplish those goals, she encourages using a body condition scoring system (1 to 5, with 1 being very thin and 5 being very fat). To fine-tune the scoring system, the scores can be broken down further into halves or quarters. Sows should be lean with adequate cover over the back, some definition of hips and shoulders, but no backbones or bones showing.

“Don't be deceived by the animal's height; big or small, the body condition should be right. By following a good body condition program, backfat levels at the end of the gestation period should be 0.56-0.64 in. More maternal genetics will have greater backfat. Following those guidelines will help control some of your feed costs,” she says.

“We recognize that a Parity 1 female is going to need a different amount of feed than a Parity 5 sow. The latter is going to be a bigger female, but she is not a growing female. So you really need to pay attention to the parity and growth phase of that sow. If you overfeed a young female, she is going to become a heavy sow that will cost you more in feed later to keep her maintained,” Greiner comments.

To keep females in proper condition, target weights for gilts coming into the farrowing house should be at 400-425 lb. (includes fetus and fluid). Growth between Parity 1 and Parity 2 should be about 25-50 lb., and about 25 lb. between Parity 2 and 3, when weights start to plateau. “You should really have a target in your system to keep those weight ranges defined,” she stresses.

Heart girth tapes and weigh scales can also help define sow weights and condition. Realize, however, that if a gilt is greater than 300-325 lb. at breeding and needs to be fed more due to her size, she won't stay in the herd as long, Greiner explains.

Greiner encourages producers to check feed drop boxes at 30 and 60 days of gestation to make sure the animals are maintaining the correct target weight and body condition.

Remember that feed charts on one farm may be slightly different on another farm where animals might convert feed differently or the environment is slightly different.

Two gestation feeding programs can be used: constant feeding or “feed-to-condition.”

The constant feeding program calls for sows to stay at the same level of feed until Day 90 of gestation, when feed is bumped up 1-2 lb. until sows farrow. “Our goal for our PIC sows would be an average of 5.25 lb. from Day 3 post-breeding to Day 90,” Greiner says.

In the feed-to-condition program, sows may get an extra bump in feed shortly after being rebred (7-30 days post-breeding) to allow them to build up any reserves they may have lost during lactation, and then be brought up to a maintenance level until Day 90 of gestation.

The feed-to-condition program can work, but it can result in wasted feed if thin sows are overfed and feed has to be cleaned out of the troughs for the first 30 days after gestation.

“We have never done a calculation to say which feeding program is better as far as feed cost savings, but I like the constant feeding level because the farm staff is feeding exactly what we want for that parity and level of condition, and there should be fewer feed box adjustments” Greiner says.

Multiple Feedings

With lighter test weight corn found in the 2009 harvest, once-a-day feeding of gestating sows may mean they are actually getting less pounds of feed than prescribed because drop boxes do not adjust for volume/weight differences.

Greiner favors feeding multiple times a day. “We believe it is a more efficient use of the animal's intake if she is fed multiple times a day; less feed in the stomach allows for better digestibility of the nutrients,” she says.

Feeding at least twice a day also gets the sow up more often for observation for illness, signs of lameness or other issues.

Feeding Lysine

Greiner says lysine as a primary amino acid is a key ingredient in the sow gestation diet that will be a primary focus of her research in the next year. Diets will be modeled during different phases of gestation to determine if levels can be fine-tuned to help sows be more productive and stay in the herd longer.

Current recommendations call for 13 grams of lysine a day during gestation, boosted to about 17 grams a day between 90-100 days of gestation to account for fetal growth.

Lactation Basics

The goal in lactation is to focus on the basics — formulating diets based on feed intake; sow health; and making sure sows get up to eat, have adequate water and the correct environment and are on full feed soon after farrowing. Sows need to eat to raise a productive litter, so these activities are paramount during lactation, Greiner says.

Make sure sows get up at least once a day. A quick visual check can work. If there is still feed in the feed tubes or feed pan from the night before, get the sow up to check her condition and whether she is milking well, she says.

Greiner's standard lactation feeding regime is 4 lb. the day a sow farrows, 6 lb. the following day, 8 lb. the third day and then full feed thereafter.

This program is vastly different than just five years ago, when full feed probably meant a maximum of 12 lb. of feed a day, she adds. Lactating sows can eat twice that amount or more today because sows in gestation are being kept leaner to boost feed consumption and increase milk production in lactation.

Feeding programs that put nursing sows on full feed from Day 0 also show merit. “We have a lot of good data to demonstrate this, and we just ran the numbers to verify it. Most preweaning mortality occurs in the first three days of lactation, so we want to make sure the sow is nursing well to avoid starveouts during this critical period,” she emphasizes.

Sow feed consumption will commonly dip at Day 5-6 of lactation, but should rebound. Just watch that the sow rebounds and doesn't dip dangerously low to 6-8 lb. of daily feed consumption. Should that occur, you may need to reevaluate the full feed program and ramp up feed levels at a slower pace, Greiner warns.

More productive females mean more feed is needed to fuel litter growth. Greiner prefers that sows eat an average of 13-plus lb. of feed per day during the lactation period. “We are taking that sow farther out in lactation, so she has higher demands for feed, and we know during the last 3-4 days of a 21-day lactation period the piglets can gain a pound a day apiece. So the sow has to eat a lot of feed to keep her out of a negative energy balance, to keep the wean-to-estrus interval acceptable for that farm.”

Keeping that sow eating well throughout lactation will pay off in fewer days to market for her litter and sow weight maintenance that will help stabilize her body condition score.

Daily lysine intake of lactating sow diets should average 58 to 62 grams, regardless of parity. Based on research conducted by Innovative Swine Solutions, LLC, when young sows (Parity 1) get less lysine (54 grams), it can add a day to the wean-to-estrus interval on average (5.25 days).

Realize that if the farm averages 12.5 lb./day of feed consumption during lactation, first parity females are consuming less feed and also less lysine.

One way to boost lysine levels is to get first parity females to consume an average of 12-13 lb. of feed daily during lactation. Feed can be presented several times a day to encourage this level of consumption; some Parity 1 females will eat that full amount in a three-hour period, says Greiner. Gilts kept in good condition can eat that much feed.

Monitor them closely, post-farrowing, to make sure they have gotten up and eaten within the first 24 hours of farrowing. Modify diets to maximize intake and avoid weight loss during lactation, she says.

To keep up wean weights, consider adding up to 4% fat to the diets in summer if feed consumption lags, she advises.

Adding 20-30% distillers dried grains with solubles (DDGS) in lactation has virtually eliminated the need to feed fat, boosted sow weight gains and enabled piglets to perform well, all while saving feed dollars, Greiner explains.

To work well, DDGS needs to first be fed to gestating sows. The sows perform quite well on DDGS, producing somewhat heavier piglets; the fiber also keeps sows from getting constipated, she explains.

“I haven't seen any problems so far in lactating sows from these feeding levels that would suggest there are any negative issues with DDGS and lactation performance,” she says.

The study by Greiner shows very positive numbers for total born, sow weight gain and a reduction in wean-to-first-service interval with high levels of DDGS added to sow diets.

One caution has been raised by some data that suggests that feeding DDGS may increase the need for additional vitamin E, produce Mulberry Heart Disease or a selenium deficiency in the offspring.

In addition, with the 2009 harvest, mycotoxin levels may be a concern. DDGS can cause mycotoxin levels to increase up to three times the levels that are commonly found in corn. Caution should be exercised when using DDGS in sow diets and careful monitoring of the feed ingredients should occur if producers choose to use them.

Other Recommendations

Make sure water delivery systems are set up so that lactating sows get plenty of water, and watch selenium and nitrate levels in water supplies.

Alternative ingredients such as plasma, probiotics, enzymes and yeast all have a place and purpose in sow diets, and can be kept in diets if it is shown they help your herd.

Data from American Protein Corp. has shown that feeding plasma to Parity 1 and 2 sows in lactation improved their feed intake by more than 2.2 lb., which is significant, she testifies.

Organic acids have also been shown to yield similar results, which can lead to reduced wean-to-estrus intervals and other benefits.

(Table 1). Feeding DDGS to Lactating Sows

Percent Distillers Dried Grains with Solubles (DDGS)





Daily feed intake, lb.





Sow weight gain/loss, lb.





Wean-to-first breed, days





Percent bred by 10 days





Subsequent total born





About the Author(s)

Joe Vansickle

Senior Editor

Joe, a native of Indiana, is a graduate of the University of St. Thomas in St. Paul, MN, with a bachelor’s degree in journalism. He worked on daily newspapers in Albert Lea, MN and Fairmont, MN, before joining the staff of National Hog Farmer in 1977. Joe specializes in animal health issues, federal regulations, environmental concerns, food safety and writing about the swine veterinary community. Joe has won several writing awards from the Livestock Publications Council. In 2002, he earned the Master Writer Program Award from the American Agricultural Editors’ Association.

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