The Effect of Split-Suckling Strategies on Piglet Pre- and Post-Weaning Performance and Livability

Researchers: Mikayla Spinler, Jason Woodworth, Mike Tokach, Robert Goodband, Joel DeRouchey, Katelyn Gaffield, Ashley Hartman, and Jordan Gebhardt

Litter size in the US is increasing.

However, sow colostrum production is not related to litter size, so as litter size increases, this does not mean the sow will produce more colostrum. This results in reduced and unequal colostrum intake among piglets in a litter.

Because colostrum intake has a large impact on the lifetime survival of pigs, management practices are being utilized to ensure adequate colostrum intake.

Split-suckling is a management practice that is implemented on a farm in an attempt to ensure that all pigs within a litter consume adequate colostrum to reduce pre- and post-weaning mortality.

Two potential split‑suckling protocols were explored. In one protocol, a portion of the litter is temporarily separated from the sow so the remaining pigs can nurse with less competition to consume colostrum. In the second protocol, the firstborn or heaviest pigs are temporarily removed from the sow to prioritize colostrum intake for later-born or light-weight pigs.

Split-suckling protocols vary across farms, and research does not indicate one best strategy that leads to the greatest reduction in pre- or post-weaning mortality.

Due to differences in split-suckling protocols utilized on farms and in research, further research is needed using a large sample size to evaluate the effect of split-suckling in a commercial setting.

A large-scale commercial study including a total of 1,513 sows (average parity 3.6; Line 241: DNA) and their litters (22,800 pigs) was conducted to evaluate the effect of two different split-suckling protocols.

Three treatments were evaluated: control, no split-suckling, and two split-suckling treatments. The split-suckling protocols were based on pig birth order or birth weight, and only litters with 10 or more pigs were included in the study.

Split-suckle treatments were applied within three hours of the end of farrowing if a sow farrowed during the day, and within 18 hours of the start of farrowing if a sow farrowed overnight. For litters split-suckled based on birth order, the first eight pigs born were marked with livestock paint as the sow was in the process of actively farrowing.

When the sow was done farrowing, the first eight pigs born were removed from the sow and placed under a heat lamp in the crate for 45 minutes. After that time, the first eight pigs born were placed back with the sow, and the later-born pigs were removed from the sow for 45 minutes. Then, all pigs were placed with the sow, and the split-suckle treatment was complete.

If farrowing was not attended and birth order could not be recorded, the eight heaviest piglets were removed first, followed by the lighter piglets.

For litters split-suckled based on body weight, the eight heaviest pigs were removed from the sow and placed under a heat lamp in the crate for 90 minutes after the completion of farrowing. After 90 minutes, the eight heaviest pigs were returned to the sow, and the split-suckling protocol was complete.

Individual pig weights were taken before any split-suckling, and these pigs were given an ear tag for individual identification.

Day 1 of the trial was defined as the day split-suckling occurred. After pig weights were taken and split-suckling treatments were applied, pigs were cross-fostered within treatment. Cross-fostering occurred within 24 hours after the completion of farrowing.

Fallback pigs, defined as small and gaunt pigs that were too small to compete with littermates, were identified between days 2 and 12 post-farrowing. Fallback pigs were removed from the litter and placed with a nurse sow.

Individual pig weights were recorded again on the day before weaning (average day 20). The reason and date for all pre-weaning mortalities were recorded. Pre-weaning mortality included only pigs that were weighed and tagged and does not include pigs that were removed and placed with a nurse sow. Litter size was recorded at the time of split-suckling, after litters were equalized, and at weaning

Did split-suckling have an impact on pre-weaning growth performance or mortality?

Litter and pig weight at weaning were not different among treatments. Pre-weaning mortality was not different among treatments, indicating that split-suckling did not impact pre-weaning survivability. These results are in agreement with five of seven split-suckle trials published from 1996 to 2023.

Pre-weaning mortality was also analyzed by birth weight, less than 2.7 lb, 2.7-3.2 lb, and greater than 3.2 lb. Split-suckling did not impact pre-weaning mortality differently based on piglet birth weight (Figure 1).

Blood samples were collected from all piglets in 45 litters per treatment, 24 hours after the birth of the first piglet in the litter.

Blood samples were used to determine immunocrit ratio, which measures the amount of immunoglobulin G in the serum of piglets. The immunocrit ratio is used as an indicator of colostrum intake, with a higher immunocrit ratio indicating higher colostrum intake.

No differences in immunocrit ratio were observed among treatments, showing that the split-suckle treatment applied did not impact colostrum intake.

A subset of pigs, 2,208, were followed into the nursery, and 882 pigs were followed into the finisher to track post-weaning growth performance and mortality. No differences in ADG (average daily gain), ADFI (average daily feed intake), F/G (Feed-to-Gain Ratio), or mortality were observed among treatments in the nursery and the finisher. Split-suckling did not impact the lifetime mortality of pigs.

If split‑suckling had no effect in the overall study population, is there a subset of pigs that will benefit from split suckling?

To answer this question, a subset of the population was used to determine if split-suckling was different based on sow parity, timing of split-suckling, and sow functional teat count.

The response to split-suckling was not different based on sow parity. Timing of split-suckling, split-suckling the same day as farrowing vs the following morning for litters that were born in the evening or overnight, did not impact pre-weaning mortality. Sows were broken down into two functional teat count groups: 14 or fewer vs 15 or more, and no differences in mortality were observed among treatments.

In litters where litter size at split-suckling was greater than functional teat count, litters that were not split-suckled had increased mortality from the time of split-suckling to day 2 compared to litters split-suckled based on birth order.

In this population, litters that were not split-suckled had a higher percentage of pigs laid on. However, in litters that had more piglets than functional teats at split-suckling, there was no difference in overall mortality from split-suckling to weaning.

The split-suckling strategies evaluated in this study did not impact pre- or post-weaning growth performance or mortality. The results of this study and past research trials show that the effectiveness of split-suckling is variable and does not show consistent reductions in pre-weaning mortality.

Caretakers should focus on investing time in other strategies to reduce pre-weaning mortality and set the wean pig up for success.

Are there better ways to invest time to improve piglet livability?

KEY TAKEAWAYS:

1. Split-suckling by birth order or body weight did not impact pre-or post-weaning survivability.
2. Caretakers should invest time in strategies to reduce pre-weaning mortality, such as:
   • Assisting sows during the farrowing process.
   • Encouraging piglets to consume colostrum.
   • Ensuring proper environmental temperatures and conditions for both the sow and piglet.

This project was supported by the National Pork Board (PR-005981) and the Foundation for Food and Agriculture Research.

Dr. Mikayla Spinler

Dr. Mikayla Spinler is a Swine Technical Sales and Service Nutritionist at Vita Plus. She completed her PhD in swine nutrition with the Applied Swine Nutrition team at Kansas State University in December 2026.