The study, which followed sows through two complete reproductive cycles, confirmed that high levels of canola meal did not compromise litter size, piglet growth, or milk quality. While sows showed slight metabolic changes when first introduced to the diet, they successfully adapted by the second cycle.
Reducing the industry’s dependence on soybean meal
For years, soybean meal has remained the gold standard for swine nutrition due to its high protein content and easy digestibility. However, the increasing volatility of global trade and the rising raw material costs have strained profit margins for pork producers worldwide.
The researchers investigated whether the second most common protein source, canola meal, could be a full replacement. They aimed to provide evidence for long-term use, as many producers hesitate to move away from traditional soybean-based formulations without proof of multi-generational safety.
Tracking performance across two reproductive cycles
The study focused on the long-term effects of this dietary shift, noting that many previous studies only looked at short-term performance over a single gestation period. By monitoring 68 sows over two complete reproductive cycles, the researchers provided a clearer picture of how a herd would react to sustained canola meal inclusion.
This longitudinal approach is critical, because sows are highly productive animals that require stable nutrition to maintain their own health while supporting the growth of their litters. The trial utilised a randomised design to compare a standard corn, barley and soybean meal diet against a treatment diet whose primary protein source was canola meal.
Sows showed resilience in body weight and condition
The research team formulated the test diets specifically for different stages of the reproductive life. During gestation, the treatment sows received a diet containing 14.5% canola meal, which increased to 24.5% during the lactation phase to meet the high energy demands of nursing.
The researchers found that the sow body weight and backfat thickness remained largely unaffected by the change in protein source over the trial’s duration. Maintaining backfat is particularly important for producers, as a sow with poor body condition is less likely to successfully rebreed or produce high-quality colostrum for her next litter.
The importance of metabolic adaptation in the first cycle
One of the study’s most significant findings was the evidence of metabolic adaptation. In the first cycle, sows on the canola meal diet showed a slightly lower weight gain during late pregnancy compared to those on the soybean meal diet.
However, this difference disappeared during the second cycle. The researchers stated that this suggested sows needed a transition period to fully adjust to the higher fibre content and different nutrient profile of canola meal. It indicated that the animal’s digestive system and gut microbiome might undergo a learning phase to effectively ferment the more complex fibres found in canola.
Piglet growth and survival remained steady
The team noted that the sows fed the canola meal diet maintained similar reproductive and litter performance, comparable with soybean meal-based diets across two reproductive cycles. This included critical metrics such as the total number of piglets born, the number of piglets born alive, and the weight of the litter at weaning.
Fortunately, the survival rates of the piglets remained high, and their average daily gain was consistent regardless of whether their mothers were consuming soybean or canola meal.
Colostrum and milk quality support nursing piglets
The quality of the milk and colostrum is another vital factor for piglet survival and growth, as it provides both energy for heat production and antibodies for immune defence. The study found that the composition of colostrum and milk remained stable regardless of diet. While there was a temporary spike in colostrum fat for the canola group in the first cycle, these levels normalised by the second cycle.
This suggested that canola meal, which contains residual oils rich in unsaturated fatty acids, might even provide a slight boost to early-stage milk energy. Overall, the nursing piglets’ nutritional needs were consistently met across both groups.
Modern canola varieties overcome historical anti-nutritional barriers
Historically, a primary barrier to using high levels of canola meal has been the presence of glucosinolates. These anti-nutritional factors can cause a bitter taste that reduces feed intake or interferes with thyroid function in pigs.
However, the researchers used modern ‘double-low’ canola varieties, which are bred to have much lower levels of these compounds. The study confirmed that the glucosinolate levels in the test diets were well below the threshold that would cause health or performance issues.
Furthermore, sows have a much higher capacity to ferment dietary fibre than younger pigs, making them the ideal candidates for these higher-fibre alternative diets.
Evaluating metabolic health through serum analysis
Researchers also took a deep dive into the animals’ blood profiles to monitor liver, kidney and muscle function. They observed a slight increase in certain enzymes, like gamma-glutamyl transferase (GGT) and creatinine, during the first cycle for sows on the canola diet.
This was interpreted as a sign of mild metabolic adjustment, or an adaptive response to the new fibre and protein sources. Like the weight gain results, these markers stabilised in the second cycle, further proving that the animals’ bodies learnt to process the canola meal efficiently over time. Additionally, no signs of clinical stress or organ dysfunction were observed in the herd.
Significant cost savings from successful transition
From a financial perspective, the move to canola meal makes a compelling case for large-scale pork operations. The researchers calculated that the canola meal formulation saved approximately 20.50 CAD per tonne, compared to the soybean meal diet.
In a high-volume production environment where feed accounts for most of the operating expenses, these savings can significantly improve the bottom line without sacrificing herd health. This economic advantage is especially pronounced in regions where canola is grown locally, reducing the transportation costs of importing soybean meal.
In conclusion, the researchers wrote: “These findings highlight the potential of canola meal as a sustainable alternative to soybean meal, with long-term benefits when diets are properly formulated based on the digestible energy and amino acids values. Future research should explore the metabolic mechanisms underlying these adaptations to further enhance the efficacy of canola meal in sow diets.”
Source: Animal
“High canola meal in sow diets: effects on reproduction, piglet growth, milk composition, serum metabolites, and nutrient digestibility over two reproductive cycles”
https://doi.org/10.1016/j.animal.2025.101752
Authors: X. Zhang, et al.
