By Dalton Obermier – University of Nebraska, PhD student in breeding and genetics
Pigs/sow/year (PSY) or pigs weaned/mated female/year are common benchmarks that define sow efficiency. Toward the top of the list of constraints producers face in maximizing those traits are piglet mortalities. In years past, genetic selection has focused on production traits, such as litter size at birth, resulting in an increase in both total number born (TNB) and number born alive (NBA). This has ultimately improved pigs weaned/mated female/year by nearly 4 units from 2005 to 2020 (21.50 versus 25.48, respectively).
However, stillborn and pre-weaning mortality (PWM) rates have remained roughly the same during that time (1.03 versus 1.08 piglets and 13.70 versus 13.00%, respectively), so we are actually observing more dead piglets per sow on average. Piglet survival, according to the 2021 PigCHAMP annual report, is just under 75% on average across all their participating farms; which is a typical value in the industry. This means that ~25% of fully formed pig fetuses will not reach the next stage of production. Not only is this a great economic burden for producers, but it is an immense welfare concern for the industry. Personally, I view piglet mortalities as one of the “low hanging fruits” in swine production.
Increasing Piglet Survival
So, how do we increase piglet survival without sacrificing litter size, altering housing conditions or implementing unpractical changes?
In animal agriculture, if you want to make change you either have to genetically select for it, alter the genome or introduce environmental changes (managerially, nutritionally, etc.). Much work has been done in the area of mitigating deaths post-partum, along with decreasing stillborn rates via genetic selection and nutritionally. However, less work has been done with naturally altering the sow’s environment without genetic or dietary change in effort to reduce stillborns.
As an industry, we have an understanding of what causes stillborn piglets, with most cases linked to the farrowing process itself. With larger litters, comes longer farrowing durations, and with prolonged births, comes greater piglet stress. This “stress” is known as hypoxia, which is reduced oxygenation at the piglet level via successive uterine contractions, reduced utero-placental blood flow or umbilical cord failure. Piglets that experience hypoxia either result in a stillbirth, or show signs of low vitality, making them a prime suspect to lack nutrient access or get laid on shortly after birth.
Along with litter size, energy depletion and fatigue at the sow level have been associated with prolonged farrowings. Pigs absorb starch from their intestines in the form of glucose, which provides energy to the pig and typically takes place in the first 4 to 6 hours after feed intake. Peter Theil found sows with a wider gap (> 18hr) between time of last feeding and onset of parturition experienced longer farrowings when compared to sows with less of a gap (< 6hr); which in turn had a negative impact of stillborn rates (10 vs. < 4%, respectively).
“In animal agriculture, if you want to make change you either have to genetically select for it, alter the genome or introduce environmental changes.”
Based on the research, Theil recommends modern, high prolific sows should be fed at least three times daily prior to farrowing to provide a constant energy supply. Other work has been done with feeding iterations pre-farrow, however no clear-cut consensus has been made on the “ideal” number of feedings per day, nor the time of those feedings.
Increasing farrowing assistance across the board can be the wholistic solution to reducing stillborn rates, however this would traditionally require the implantation of a 24-hour farrowing schedule, creating shifts that revolve around those “heavy farrow days”, or perhaps by using a “batch farrow” program. These methods have been difficult to adapt due to labor issues or for other logistical reasons.
Ideally, sows would shift toward daytime farrows when there will be more assistance available. Producers have tried this process via induction, but some of the risks associated have created skepticism. So, we tried to tackle this issue from a more natural approach.
A Deeper Look at the Studies
In our first study (Study #1), we implemented a common practice known in the cattle world as the “Konefal Method,” where ranchers feed heifers at night in hopes of inducing more day time calvings. We hypothesized that by doing this with sows, we might see the same change. Thus, the objective of the first study was to determine if feeding sows overnight can alter farrowing times to better align with farrowing staff schedules, and ultimately reduce stillborn rates.
After the completion of that trial, we ran a pilot study (Study #2) to help our understanding on feeding iterations and their role with farrowing duration and stillborn rates. Thus, the objective of the second study was determining any reproductive performance differences amongst different pre-farrow feeding iterations.
Both of the current studies took place at a 5,000-head sow farm in Nebraska during summer 2020. For both studies, at ~113 days of gestation sows were moved from gestation to farrowing (18 rooms with 56 crates/room).
In Study #1, sows (1,171) were randomly assigned to one of two treatments upon entry to farrowing:
• Control (CON) – 100% of daily feed allocation from 7 to 10 a.m.
• Alternative (ALT) – 100% of daily feed allocation from 2 – 5 a.m.
In Study #2, sows (302) were blocked by parity and randomly assigned to one of three feeding treatments:
• Once – 100% of daily feed allocation from 6 to 9 a.m.
• Twice – 50% of daily feed allocation from 6 to 9 a.m. and 50% from 3 to 6 p.m.
• Six – 20% in the periods from 6 to 8:30 a.m. and 9 to 11:30 a.m., and 15% allowed in periods from 12 to 2:30 p.m., 3 to 5:30 p.m., 6 to 8:30 p.m., and 9 to 11:30 p.m.
All sows in both trials were allowed a daily limit of 5 lb. Quantity and feed delivery time was automated through the use of the Gestal Solo lactational feeders.
During Study #1, a 24-hour farrowing observation schedule was put into action to record reproductive performance and timing. Three technicians reported the time of the first observed piglet, the number of piglets at subsequent checks (~30min) and the time the last pig was observed for each sow. Standard farm procedures for induction, farrowing assistance, and treatments were maintained throughout both studies. During Study #2, reproductive performances were recorded at the conclusion of farrowing.
“This is revolutionary because it didn’t require farm schedules to change nor subtracted away from the progress we’ve made genetically and nutritionally.”
Promising Application
Any sows that were induced, didn’t have at least one-day on assigned treatment or had more than two piglets before onset time was recorded were removed from both data sets. In total, 1,016 commercial F1 sows were used for statistical analysis in Study #1 and 276 sows were used in analysis for Study #2.
In Study #1, estimated marginal means showed that ALT sows farrowed earlier than CTRL sows (12:04 vs. 12:56PM, respectively), tended to have shorter farrowing durations (6:09 versus 6:33 hour, respectively) and had lower stillborn percentages (8.40 versus 9.74%, respectively). All together, sows fed the ALT treatment completed farrowing nearly 80 minutes earlier and had a reduction in stillborn percentage by 1.34%. In Study #2, significant differences were not captured across groups due to the lack of sample size, but on average sows fed once had greater stillborns compared to sows fed twice or six times (13.82, 11.93 and 11.51%, respectively).
We were successful in changing the farrowing times in ALT fed sows, while subsequently reducing stillborn percentages. The advantages are clear when evaluating sows on an individual basis, when dissecting farrowing time in relation to staff hours. I believe these benefits can be magnified across the farm with further investigation. The ALT time (2 a.m.) was not based off of recent literature, it was more so just a starting point. Perhaps feeding in the late evening or earlier in the middle of the night, or by feeding the ALT treatment further out pre-partum, could alter these farrowings even more.
In regard to Study #2, more observations were needed in each treatment group to yield significance, however the raw data is promising and coincides with Peter Theil’s work. From this data, it is difficult to determine if the impact of feeding iterations is linear or quadratic, given the absence of three, four and five feed periods; but I’m confident in the groups currently working in this area to develop further understanding and in time will evolve in a novel application.
I’ve outlined two simple ways in which automated feeders give producers opportunities to improve key benchmarks such as pigs weaned/mated female/year by improving stillborn rates. This is revolutionary because it didn’t require farm schedules to change nor subtracted away from the progress we’ve made genetically and nutritionally. The positive tangibles seen through the use of feeders, go far beyond saving piglets; with mechanisms designed to better the sow’s lifetime reproductive performance while making life easier on staff. As more commercial implementation is seen with such technologies, I’ll remain optimistic that further practical research will be feasible to create sudden, positive change for the producers and most importantly the pig itself.
Literature Cited
Decaluwé, Ruben & Janssens, Geert & Declerck, Ilse & Kruif, Aart & Maes, Dominiek. (2012). Induction of parturition in the sow. Vlaams Diergeneeskundig Tijdschrift. 81. 158-165.
Konefal, G. 1980. Daytime Calving – the Konefal Method. Ninth Annual Cornbelt Cow-Calf Conference, Ottumwa, IA.
Knauer, M.T. (2013). US swine industry productivity analysis, 2005 to 20010. Journal Swine Health Productivity, 12(5):248-252.
Gunvaldsen RE, Waldner C, Harding JC. Effects of farrowing induction on suckling piglet performance. J Swine Health Prod. 2007;15(2):84–91.
MetaFarms: Production Analysis Summary for U.S. Pork Industry: 2017-2020. 2021.
PigChamp: USA 2021 - year end summary. 2021.
Sorensen, L.S. More frequent daily sow feedings reduces the number of stillborn piglets. Aarhus University. DCA – Danish Centre for Food and Agriculture, November 9th, 2017.
van den Bosch, M., van de Linde, I.B., Kemp, B., van den Brand, H. Disentangling Litter Size and Farrowing Duration Effects on Piglet Stillbirth, Acid–Base Blood Parameters and Pre-Weaning Mortality. Frontiers in Veterinary Science. Vol. 9. 2022
More from Farm Journal’s PORK:
What Do You Need to Pay Attention to Now Regarding Swine Health?
Economists Urge Pig Farmers to Watch Out for These Threats to Pork Outlook
New Products on Display at 2022 World Pork Expo
