Is it Time to Rethink Gilt Development?

Sow mortality has been making the headlines as producers grapple with rising sow death loss in the U.S. pork industry. Although the topic deserves discussion, some experts believe it is time to focus on gilt retention.

“Sow mortality has been scrutinized ad nauseum, but gilt retention hasn't been focused on quite as much. I think it may be the top of the bottleneck when it really comes back to what we can do to improve things downstream in production,” said Hyatt Frobose, USA commercial director at Jyga Technologies-Gestal, during a recent webinar.

In a 2003 study published by Ken Stalder at Iowa State University that was reiterated in 2017, it showed on average, replacement females failed to generate a positive return on investment until parity three to four, depending a little on farm size and conditions, Frobose explained. 

“In general, our females aren't really paying for themselves until they've stayed in the herd for three parities,” he said. “What's concerning to me is we know that the parity averages for the U.S. sow herd, as represented by Agristats and Swine Management Systems, are only averaging about 2.4 to 2.6. So somewhere, we're not really matching up with when these sows are paying for themselves. It seems to me we're leaving opportunity on the table.”

How can we get these animals into their most productive parities? 

In North America, most growing gilts are housed in similar housing environments compared to their growing-finishing counterparts. Ad libitum feed access is provided until just prior to breeding, with most gilts receiving diets with marginally elevated levels of amino acids, vitamins and trace minerals. While this rearing strategy is prevalent due to convenience, consistency and availability, recent research suggests it may not necessarily be best for sow longevity. Frobose suggests it’s time to rethink how gilts are raised and developed.

Limit-Feed Gilts
Most of the farms Frobose works with provide ad libitum feed access for gilts from the time they enter the gilt development unit (GDU) until they move into breeding stalls. He said a common issue in commercial GDUs is that gilts grow too fast and are bigger than ideal. Research indicates these gilts are more likely to prematurely exit the herd. 

Frobose offered producers two suggestions to help optimize gilts, as they move into breeding. 

1. Change feed presentation method. Change feed presentation method to moderately restrict gilts from the end of the nursery period by targeting gains of 1.65 lb/day to1.76 lb/day until flushing two weeks prior to breeding.  

2. Change the feed composition. If ad libitum feeding is the only option, add fiber, increase micron size and adjust energy and lysine targets downward by 10% to 15% in order to slow growth rate.

“Controlling gilt weight at breeding may also offer downstream diet savings, by moderating mature sow size and reducing annual maintenance costs. Simple math would suggest that reducing gestation feed by as little as 150 g/d could reduce annual feed costs by USD $9/sow/year,” Frobose said.

Revisit GDU Design
GDU design is often an afterthought in sow farm design, Frobose said. 

“It's human nature to lay out your ideal floor plan and equipment and technology. Then, when you get down to the price tag, we try to figure out where we can shave off some dollars and cents to make it more palatable,” Frobose said. “Unfortunately, in my experience, the GDU becomes a target area that gets the axe on some extra dollars and cents. I think that's unfortunate, because we really should be treating that as the proving ground for the next gilts that are going to be entering the herd.”

GDUs are often designed like a grow-finish environment. Frobose said this may be convenient and easier, but he argued it may not be best for the gilt long-term. 

“Clearly, we’re getting these gilts to grow fast enough, and we don't really need them to grow any faster than they already are,” he said. “So, if we're ad lib feeding in the GDU (which I think needs questioned), are wet-dry feeders the right way to go to maximize growth, or would we be better off with a dry feeder that can maybe help us slow down that growth just a little to keep gills from getting too big?”

Frobose suggested producers implement these ideas into GDU design.

1.    Mimic the environment of the sow farm. Frobose suggested using the same flooring and maintaining the same type of ambient temperature environment and air quality to prepare gilts for moving into the actual sow farm flow. Avoid creating new stresses as they move into the breeding environment.

“Waterers are a big thing that I’ve seen messed up,” Frobose said. “It’s easy to make the mistake of having a different waterer type in the GDU pens, or even in gestation, than what those gilts will experience in farrowing. I can count too many times where I've seen a gilt that didn't find the water or know how to drink when she got into farrowing. That can really set her on the wrong path as she enters production.”

2.    Maintain group cohesiveness. If possible, maintain the hierarchy of a group of gilts that were raised together by keeping them together as they move from breeding into pen gestation to minimize aggression and lameness. Research shows grouping gilts or even gilts and P1s separately from older sows can increase farrowing rates and help improve retention of those animals in the herd, he added.

“GDUs are continuous flow and that's one of the key differences from most grow-finish environments that are managed all-in, all-out. It's always a challenge of how to optimize stocking density with our different age groups,” he said. “But it’s something we've got to continue to think about.”

3.    Consider precision feeding technology. Most would agree it’s best to give gilts multiple diets throughout the grow-finish period, Frobose said. 

“Unfortunately, in my experience, the in-herd nutritionists are usually the last people asked on pen design or barn design for GDUs, and so they end up kind of effectively hamstringed by whatever the construction folks decide is the best thing for the GDU,” he added. 

Additional feed systems usually require more gilt movement, increasing labor requirements that are already lacking in the GDU. Frobose said blending technologies, however, can enhance pen flexibility and help deliver multiphase diets to a pen of gilts based on their age and weight while reducing diet cost and increasing feed efficiency. 

Invest Wisely
Gilts may have historically been thought of as a cheap investment, but as an industry, we have become accustomed to introducing gilts at an average of 70% to breed at a 55% annual replacement rate, Frobose explained. 

In a 2019 study, Derald Holtkamp, Iowa State University, showed that implementing a gilt management program yielded a 10% reduction in annual gilt replacement rate (62% to 52%) on a 2,400-head sow farm and resulted in 829 additional marketed pigs and 222,310 additional pounds of pork produced per year, ultimately yielding a benefit-to-cost ratio of 2.41:1.

“Once you account for genetic premiums, overhead costs and the currently low value of cull sows, isn’t it worth realigning your gilt development programs to improve herd retention?” Frobose asked.

More from Farm Journal's PORK:

A Look at the ‘Unknown Factors’ in Sow Mortality

No Magic Bullet to Reduce Pre-Wean Mortality in Pigs

Remodeling Facilities: You Have Options