I. Bottleneck of Pig Feed Efficiency and the Critical Role of the Suckling Period
Compared to poultry, the feed efficiency of pigs has consistently been less than satisfactory. However, it is indeed observed in production that finishing pigs slaughtered at 110 kg body weight can achieve a feed conversion ratio (FCR) of less than 2:1, indicating the economic potential of pigs. As mammals, the fundamental factor affecting the economic benefits of pigs lies in the suckling stage. In other words, the suckling process cannot fully meet the economic benefits desired for finishing pigs. However, as mammals, the genetic requirements of pigs include this suckling stage. Let’s examine the problems in this stage and what improvements can be made, as well as potential solutions.
II. Lagging Digestive System Development During Suckling and its Economic Impact
Firstly, the existence of suckling as a life process in mammals is a result of evolution. Analyzing it, the evolutionary leap from oviparity to viviparity was undoubtedly enormous in animal history. However, such a significant advancement could hardly be perfect in one step. Viviparity requires the mother to consume vast amounts of nutrients and excrete a huge volume of fetal developmental metabolic waste products, a quantity potentially overwhelming for the mother. Thus, animals chose a compromise: the fetus first completes the development of the most critical life organs within the uterus, while secondary life organs continue their development after birth. Through observation, it becomes clear that the gastrointestinal digestive system of animals is one such secondary life organ in evolutionary history.
Data can support this viewpoint:
By recording the total weight of the gastrointestinal tract (or the entire digestive system) and the birth weight of newborn piglets, and then measuring these again at weaning (e.g., 28 days), an astonishing fact emerges: within four weeks, body weight increases approximately fivefold, but the weight of the digestive system increases more than tenfold. This indicates that the digestive tract of mammals continues to develop during the suckling stage. The nutritional composition and state of breast milk, or the suckling process itself, are specifically designed for the continuous development of the gastrointestinal tract (digestive system). Understanding this is crucial for designing post-weaning feed.
III. Drawbacks of Traditional Early Weaning Models and Gastrointestinal Issues
This raises a new issue: in commercial production, the health and strength of the gastrointestinal tract are the foundation for raising economic animals, as they are the first critical link in converting feed into animal products. However, considering the entire livestock industry, operators prefer this stage to be as short as possible. This is why the suckling period for wild boars is typically longer than six months, but in industrialized pig farming, it is compressed to four weeks or even less. Of course, due to the pressure of African Swine Fever, many pig farmers have had a change of heart and are increasing the suckling period to five weeks. Essentially, to maximize the economic benefits of pig farming, the weaning time is an optimal balance point determined by a combination of factors including the pig’s genetic potential, environmental control capabilities and operating costs, the scientific design and production of feed, disease control and medication costs, the number of sows raised and farrowing house capacity, etc.
IV. Two Main Approaches to Solving the Weaning Problem
Our current customary four-week weaning model (and sometimes even earlier weaning) has a fundamental problem: the piglets’ gastrointestinal tracts are not fully developed. Post-weaning feed is designed according to the nutritional needs of finishing pigs. (The nutrients needed by the mucosa are unrelated to whey. Traditional creep feed uses 150 kg or more of whey powder per ton of complete feed, but this achieves two things. One is something that 5 kg of whey powder can accomplish, which is to activate the lactic acid bacteria in the gastrointestinal tract—this can now be achieved faster and better with more efficient complex bacterial cultures.)
The second goal was to try to bypass post-weaning edema caused by insulin through the high lactose content in such high levels of whey powder. However, the reality is that after weaning, starch raw materials such as corn or extruded broken rice are invariably used. Insulin edema is unavoidable.
No one has considered the developmental needs of the gastrointestinal tract at this stage. Therefore, the consistent global consequence is: within the first three days after weaning, the gastrointestinal mucosa universally experiences atrophy, collapse, shedding, and regeneration. Insulin edema appears 3-6 days after weaning—a uniform occurrence. The dual factors of gastrointestinal mucosal nutrient deficiency and insulin edema exacerbate gastrointestinal mucosal inflammation within the first three days after weaning. As a result, piglets lose weight during the first three days after weaning, and their growth rate is zero for the first week. This phenomenon has a profound impact on the overall economic benefits, leading to at least a two-week delay in slaughter time and an increase in FCR of 0.1%-0.15%.
Faced with this problem, there are two ways to solve it.
The first is to postpone weaning to five weeks, a solution with very significant overall benefits.
The second is to change the design of the post-weaning feed, with the healthy development of the gastrointestinal mucosa as the primary consideration.
V. Advantages and Future Potential of Novel Post-Weaning Feed
The new post-weaning feed model launched by livestock professionals is a completely different attempt from the traditional approach. Because the feed provides sufficient nutrients for the development of the gastrointestinal mucosa, it ensures the continued healthy development of the gastrointestinal mucosa after weaning. The resulting high feed intake, in turn, provides more nutrients for the gastrointestinal mucosa, creating a virtuous cycle. After weaning, the average daily gain remains higher than the average level during suckling. With the emergence of this product and solution, the pig farming industry can more easily find a new balance point between early weaning and overall efficiency.