By Eric Weaver and Lauren Olson, South Dakota State University

In our previous article on research focusing on the sow, we discussed narrowing our focus on mortality to the time around farrowing. We know that losing sows from mortality is inefficient and costly. The periparturient period is one where we believe we can make an impact.

The SDSU research herd is a valuable resource because the myriad of issues we face in sows farrowing are the same as what the industry faces. The conditions and replacement rate and mortality of sows in the SDSU herd is typical of current industry norms, except for rewarding good sow behavior in research with a marshmallow treat.

What we don’t see in farrowing studies are >100 sow groups that have 0% removals – which is often what we see with published sow studies. Lameness, illness, farrowing difficulty and causes of mortality in research are unreported. Large sow studies have not improved the industry’s care of sows nor lowered sow mortality rates in part because the valuable data – farrowing duration, complications, assistance and necropsy findings - for the sow are labor intensive to collect.

To study sow health and mortality, studies with more control, and identification of case history and causes of death are more informative than studies that report on an outcome of sow health as number of pigs born, weaned and litter weights.

The industry discusses the need for sow robustness but the definition changes depending on the perspective. Either prolificacy or longevity, or both, may be considered as traits of robustness. But sow robustness as a measurement, evaluation tool, or index does not rank high enough to be included in sow records.

Age and parity of the sow, in sow replacement practices, reduce the value of the sow – much like a car. The reality is that breeding for sow longevity, a trait of robustness, is difficult to do and it takes a back seat to prolificacy (pigs/sow/year “P/S/Y”).

Given a choice of breeding values for the two traits, the market chooses P/S/Y and feeding and management practices follow suit. If a nutrition change is to be considered in sow farms and it doesn’t result in a P/S/Y gain, it had better reduce cost. A sow that is highly productive in just one parity has very close to the P/S/Y or days in production 3-4 parity sow that would have with just one recycle. But it takes an investment of 2 or 3 one parity sows to get the same number of pigs produced.

The loss of a sow is a major expense, loss of feed (500 – 600 lbs of feed) and efficiency. Rather than robustness or longevity, think durability and cost of ownership vs a lease. Durability is the ability to last a long time without significant deterioration i.e., successive farrowings with good production and low mortality. With a car, you all will change the oil to extend its value. The sow needs the same attention to be durable.

Will simply targeting mortality rates change mortality rates? Most certainly if you believe Goodhart’s Law “When a measure becomes a target, it ceases to be a good measure.” Sow mortality rates can be reduced if procedures for fixing prolapses and more aggressive culling strategies for prolapse symptoms, lameness or thin sows are employed.  The use of intensive farrowing management, and improved selection are also effective. Which of these are most valuable in promoting durability and reducing cost of ownership?

As far as caring for sows, the shortened quote attributed to W. Deming, “You can't manage what you can't measure”, applies to studies that don’t report on health issues or mortality. But, consider the correct quote with its context, “It is wrong to suppose that if you can’t measure it, you can’t manage it – a costly myth.” W. Deming.

If the need for phase feeding of sows wasn’t clear before, the clouds are lifting, and we can see that the evidence for a late gestation diet for today’s highly prolific sows is clear now. While the recommendations for amino acid needs in lean highly prolific sows are out of date, needs can be estimated based on body composition and fetal demands (NRC, 2012.) Evidence that can be used to build prediction models for nutrient needs is helpful in feeding sows. Production research finds it difficult to remain current.

Late gestation feeding studies published from 2016-2019 often reported 13-14 total pigs born, the lower third of today’s sow herds. Clearly, the late gestation sow in 2023 has an increased demand for amino acid needs driven by a litter size and weight that has increased >20% in the past 10 years.

Don’t expect a free lunch – the essential nutrients must be provided for sow and pigs. The highly prolific sow (>16 pigs born) will provide for the needs of the pig at the expense of her own needs.  

Gestating sows in the SDSU herd in recent studies have less backfat than 8-10 years ago and they are gaining >50 lbs. in the last 30 days of gestation - as much as finishing pigs on less feed. Feeding levels and amino acid supply is unchanged in herds that don’t bump feed and bump-feeding provides only 3 g per day in sows. So, demand is exceeding supply.

Late gestation sows require at least 20 g lysine equivalent amino acids per day – which is 4.5 to 5.0 lbs. of a typical lactation diet or an estimated $3 per farrowing event. Amino acids are used more efficiently if fed multiple times a day so feeding 3-4 times before farrowing provides better timing on both energy and amino acid availability, which can help the sow through the intensive exertion of farrowing and recovery.

Yes, there are important research questions. Will feeding highly prolific sows more frequently change farrowing duration and mortality rates at farrowing?  Do specific nutrients have promise in reducing mortality? The data available is very limited. We need to work on changing that, but it is intense work. Here are some initial observations from our barn time and data collection in studies.

Meeting the amino acid needs, amongst others, of the sow in late gestation and before farrowing can be managed and the return on that investment is likely to the sow’s benefit – less lean and protein loss through farrowing and lactation, increase in farrowing ease, less labor caring for difficult farrowings, and lower morbidity and mortality – NOT a higher value pig.

The demand and supply balance must be assessed by focusing and measuring the impact on the sow. We have considered reporting on late gestation and lactation feeding studies without mentioning the impact on the litter or the pig - so that the focus is on the sow. To achieve greater efficiencies, sow durability and a different outcome for sow mortality rates, feeding and management practices need to change and align with the greater demands of farrowing larger litters.