Research Results

Feed Blending Pays: A Practical Path to Precision in Grow-Finish Barns

By Alexia Godbout, agr. M.Sc. & Dalton Obermier, PhD.

In grow-finish barns, the target is consistent growth at the lowest cost per kilogram of gain. Feed cost is the largest lever, but so is precision. Traditional phase feeding can meet the “average” pig’s needs while still leaving room for over- and under-supply of nutrients within a pen. Feed blending is one practical way to close that gap.

This article explores the benefits of adopting a feed blending strategy in the grow-finish stage, with a focus on the real economic value it can yield without sacrificing performance.

Why Traditional Phase Feeding Leaves Money on the Table

Traditionally, a three- to four-phase feeding program is used in grow-finish production, where the SID lysine concentration of the feed decreases with each phase, assuming an increase in feed intake and a decrease in the capacity for protein deposition (Moore et al., 2012; NRC, 2012). This approach is designed to meet the nutritional requirements of most pigs, but it does not account for within-pen differences in body weight and feed intake (Pomar & Remus, 2019). As a result, some pigs may receive insufficient available lysine to fully meet their growth potential (Main et al., 2008), while others receive more than required – raising cost and increasing nutrient excretion (Pomar et al., 2021). In the end, only the “average” pigs are truly fed according to their needs. This is illustrated in Figure 1.

Figure 1 SID lysine requirements within a pen

Figure 1. Illustration of SID lysine requirements (g/kg) within a pen (linear lines) compared to SID lysine received from a traditional four-phase feeding program

Ideally, to optimize growth and improve efficiency, each pig or similarly grouped pen would receive a diet tailored to their specific needs (Cloutier et al., 2015). Feed blending is one way to accomplish that. Feed blending uses two base diets (typically a low-lysine and a high-lysine formulation) and mixes them at variable ratios to match evolving requirements over time. Instead of fixed phases, the blend can be adjusted routinely to better align nutrient supply with the pig’s expected intake and growth.

Trial Overview: Group Precision Feeding with Two Diets

In a trial conducted at JYGA’s commercial grow-finish barn, we evaluated group precision feeding using a system capable of blending two diets at the feeder (GESTAL EVO Opti). This feeding system can deliver and blend two distinct feeds directly in the barn. Two batches of growing barrows and gilts were fed using this technology.

How the Feeding Programs Worked

The Test group received a tailored blended diet, with the blend adjusted every week based on either the average feed intake or the average pen weight during weeks when pigs were weighed. This allowed the SID lysine concentration to shift over time, ranging from 0.59% to 1.09%, depending on how much of the low-lysine and high-lysine diets were blended.

Meanwhile, the Control group followed a more traditional approach. They were fed a standard four phase feeding program created by blending fixed ratios of the same low-lysine and high-lysine feeds as previously. Table 1 shows the specifications of the four diets offered.

Table 1. Nutrient specifications of the standard four-phase feeding program

Analysis Phase 1 Phase 2 Phase 3 Phase 4
Total lysine, % 1.22 1.08 0.898 0.788
SID1 lysine, % 1.09 0.95 0.79 0.69
CP2, % 18.6 16.9 14.8 13.5
NE3, kcal/kg 2475 2486 2499 2507
1 Standardized ileal digestible.
2 Crude protein.
3 Net energy.

The trial included 1,076 pigs in the Control group and 1,085 pigs in the Test group, with average initial body weights of 37.57 kg and 37.24 kg, respectively. Pens were stocked at a rate of 17 to 28 pigs per pen (8 ft²).

One More Key Detail

To improve the accuracy of meeting nutrient requirements at the pen level, pigs were sorted by visual assessment of body weight at arrival into similar weight ranges and then randomly assigned to treatment.

Equal representation of weight classes was seen across treatment groups.

What it Meant for Growth and Feed Cost

To assess the value of feed blending, we looked at two key outcomes: growth performance and feed cost.

Results: Growth Performance

As shown in Table 2, growth performance was comparable between treatments across the 105-day period, with similar rearing time and carcass weight. Feed intake was slightly lower in the Test group, and the blending strategy reduced estimated SID lysine intake by 12.9% versus the standard four-phase program.

Results: Feed Cost

That decrease in SID lysine intake translated into real savings. Feed cost decreased by 0.05$CAD (≈ 0.04$USD) per pig per day in the Test group compared to the Control group. When expressed per kilogram of live weight (LW), that represents 1.14$CAD per kg LW (≈ 0.37$USD/lbs) for the Test group versus 1.19$CAD per kg LW (≈ 0.39$USD/lbs) for the Control group. Over a full 105 days rearing period, feed blending added up to a total benefit of 5.25$CAD per pig (≈ 3.83$USD).

Table 2. Growth performance and feed-cost outcomes for finishing pigs: traditional four-phase program (Control) vs. weekly adjusted feed blending (Test).

Control ± SE Test ± SE
Average rearing time, days 105 ± 4.00 105 ± 2.50
Average carcass weight, kg 116 ± 0.79 115 ± 0.80
ADFI, kg/day 2.92 ± 0.03 2.86 ± 0.09
SID lysine intake, g/day 23.2 ± 0.28 20.2 ± 0.19
Feed cost, $CAD/pig/day 1.15 ± 0.03 1.10 ± 0.04
Feed cost, $CAD/kg LW 1.19 ± 0.03 1.14 ± 0.04

Sensitivity Check: Standardizing Feed Intake

Although real, the economic results might have been slightly amplified by the lower ADFI observed in the Test group. Because ADFI was slightly lower in the Test group (a difference not expected from the feeding strategy itself), we also recalculated economics assuming equal ADFI for both treatments (2.89 kg/day) to ensure a fair comparison.

Under this standardized scenario, the Test group still achieved an advantage of 0.03$CAD per pig per day (0.02$USD) compared with the Control group. Over the full 105-day rearing period, this represents total savings of 3.15 $CAD per pig (2.30$USD).

Table 3. Economic outcomes recalculated under equal feed intake (ADFI = 2.89 kg/day) for both treatments.

Ctrl Test
ADFI, kg/day 2.89 2.89
SID lysine intake, g/day 23.0 20.4
Feed cost, $CAD/pig/day 1.14 1.11
Feed cost, $CAD/kg LW 1.18 1.15

Takeaway: Precision That Pays

These results highlight the value of adopting a needs-based feeding approach. Feed blending proved effective at reducing feed costs while maintaining growth performance. By integrating feed blending into grow-finish barns, producers can improve the overall efficiency of their barn. This strategy helps each group of pigs reach its full growth potential while lowering feed costs. In a context where every kilogram of feed counts, feed blending offers a practical way to protect both performance and profitability.

For producers interested in adopting feed blending, the first step is identifying two practical basal diets, and a blending schedule that aligns with your herds expected intake and growth. Even modest adjustments can reduce nutrient oversupply while maintaining performance, especially in barns currently relying on fixed phases and manual feed change.

Practical Implications for Conventional Barns

The results above compare two feed blending based programs delivered with an electronic feeding system. For barns still using a traditional hopper and a three to four-phase feeding program, the opportunity for additional savings with feed blending may be even more significant.

References

Cloutier, L., Pomar, C., Montminy, M. L., Bernier, J. F., & Pomar, J. (2015). Evaluation of a method estimating real-time individual lysine requirements in two lines of growing–finishing pigs. Animal, 9(4), 561-568. doi: 10.1017/S1751731114003073

Main, R. G., Dritz, S. S., Tokach, M. D., Goodband, R. D., Nelssen, J. L., & DeRouchey, J. M. (2008). Effects of feeding growing pigs less or more than their estimated lysine requirement in early and late finishing on overall performance. The Professional Animal Scientist, 24(1), 76-87. doi: 10.15232/S1080-7446(15)30813-5

Moore, K. L., Mullan, B. P., & Kim, J. C. (2012). Blend-feeding or feeding a single diet to pigs has no impact on growth performance or carcass quality. Animal Production Science, 53(1), 52-56. doi: 10.1071/AN12053

NRC. 2012. Nutrient requirements of swine. 11th rev. ed. Washington, DC: National Academic Press.

Pomar, C., Andretta, I., & Remus, A. (2021). Feeding strategies to reduce nutrient losses and improve the sustainability of growing pigs. Frontiers in Veterinary Science, 8, 1-13. doi: 10.3389/fvets.2021.742220

Pomar, C., & Remus, A. (2019). Precision pig feeding: a breakthrough toward sustainability. Animal Frontiers, 9(2), 52-59. doi: 10.1093/af/vfz006

Additional Reading