Impacts of Liquid Feed on Pigs at Different Growth Stages

Pigs are omnivores with diverse dietary needs. To thrive, they require a balanced diet consisting of fiber, energy, protein, vitamins and minerals, which makes feed a critical part of pig farming. So which option is better, dry feed or liquid feed? From practical experience, pigs clearly prefer liquid feed. Just as humans find porridge and cooked dishes more palatable than dry food with plain water, the same logic applies to livestock.

The liquid feeding system boasts numerous advantages and is more suitable for pig farms than traditional dry feed lines. Its automatic mixing and conveying system blends water and dry ingredients into feed with a preset consistency (typically a ratio of 3 parts water to 1 part dry feed). The mixture then undergoes elaborate fermentation under controlled conditions including pH value, temperature, water-to-feed ratio and fermentation accelerants to produce finished liquid feed. Finally, the fermented liquid feed is delivered to all pig houses via pipelines under system control. Every mixing and conveying unit is programmed for dedicated cleaning and disinfection, with strict protocols followed to meet hygiene standards throughout the process.

Fermentation is the core concept and greatest strength of the liquid feeding system. This process delivers substantial benefits to sows, piglets and finishing pigs fed with liquid feed.

1. Effects of Liquid Feed on Sows

Like all animals, pigs need constant access to clean fresh drinking water. Conventional dry feed only contains 15% moisture, which is far from sufficient to meet sows’ water demand, especially for lactating sows.

As the core of pig breeding, sows will suffer inadequate feed intake for milk production if deprived of sufficient nutrients and water. This commonly leads to reduced milk yield, severe body condition loss and prolonged estrus interval after weaning, ultimately increasing the culling rate of sows. Liquid feed solves this problem perfectly by supplying nutrients and water simultaneously. It effectively boosts the dry matter intake and overall productivity of lactating sows.

For gestating sows, the large volume of liquid feed creates a lasting feeling of satiety in the stomach and keeps the sows calm. In addition, the evenly mixed liquid feed has superior palatability and improves the feed conversion ratio.

(Pictures: Liquid feed discharge outlet in gestation house; On-site installation in farrowing house)

2. Effects of Liquid Feed on Early-Weaned Piglets

Newborn piglets rely on breast milk, which is tasty, nutrient-dense and easy to digest. Weaning means sudden separation from the sow and a switch to dry feed. The resulting weaning stress is a universal challenge for all pig farms. At this stage, piglets’ digestive systems are not fully developed, and they tend to experience poor appetite, weight loss and diarrhea. The drastic change in taste, texture and dryness of feed makes swallowing difficult. Piglets need a long adaptation period, during which their feed intake fails to reach the optimal level and growth rate may even decline. Therefore, a smooth weaning transition is vital to the subsequent growth of piglets.

Liquid feed is widely recognized as an effective solution to alleviate piglet weaning stress. Liquid feeding systems help farms maximize profits by meeting the nutritional requirements for healthy growth and performance of weaned piglets, mitigating growth retardation caused by weaning, cutting costs and raising revenue. The underlying reasons are as follows:

By-products from the food industry can be incorporated into liquid feed with optimized formulas. Such feed features balanced nutrition and high digestibility, increasing piglets’ feed intake, enhancing growth performance and lowering mortality rates. Research shows that compared with pellet feed of the same nutritional level, liquid feed delivers higher feed intake and faster growth rate for piglets over four feeding cycles.

Thanks to its good palatability, uniform composition and balanced nutrition, liquid feed improves the intestinal health and physiological functions of weaned piglets. After weaning, the pH value in piglets’ stomachs rises sharply, which fails to inhibit the reproduction of pathogenic bacteria. Liquid feed can lower gastric pH and suppress the growth of pathogens.

3. Effects of Liquid Feed on Finishing Pigs

Farmers have long used natural feeds such as grass and vegetables for pigs. Water accounts for 50% to 67% of a pig’s body weight, so adequate water intake is essential for pig health and growth — this is one major reason to promote liquid feeding. Moreover, liquid feed improves the digestibility of nutrients. Its raw materials are ground into much finer particles than those of dry feed, expanding the contact area with digestive enzymes, accelerating enzyme penetration and boosting enzyme activity. By altering the physical, chemical and biological properties of diets, liquid feed exerts a positive influence on pig health and production performance. Finishing pigs on liquid feed reach slaughter weight faster than those fed with dry feed.

In the finishing stage, the liquid feeding system can fully utilize low-cost unconventional feed ingredients, such as liquid amino acids, enzymes and food industry by-products (starch processing residues, brewing by-products, potato processing by-products, etc.). Higher dry matter digestibility reduces nitrogen and phosphorus excretion, easing environmental pollution. In terms of feeding performance, liquid feed increases daily feed intake and average daily gain, optimizes feed efficiency and improves pigs’ internal physical condition.

Tests prove that pigs consume liquid feed much faster than pellet feed and meal feed:

· Liquid feed intake rate: 0.494 g/s

· Meal feed intake rate: 0.245 g/s

Pigs spend less time at the feeding trough, which reduces feeding competition and ensures even feed intake across the herd.

4. Additional Advantages of Liquid Feed

4.1 Effective Prevention of Feed Mold

Feed mold is a severe problem in feeding management. In hot and humid regions, dry feed outlets are prone to dampness and mold growth. In cold regions, cold outdoor dry feed will cause condensation when transported into indoor pipelines, also leading to mold formation. In contrast, pipelines of liquid feeding systems are always filled with water and maintain an anaerobic environment, which effectively prevents mold. Warm water can be used for liquid feed in cold areas to avoid pipeline condensation, reduce pigs’ energy loss and prevent diarrhea caused by cold feed.

4.2 Flexible and Convenient Installation

Liquid feeding systems are adaptable to pig farms with various layouts. Driven by feeding pumps, their pipelines can be arranged more flexibly in terms of angles and directions than dry feed systems. For remotely located pig houses, intermediate tanks can be used for relay transportation. Besides, the system can operate continuously day and night. Farmers only need to conduct routine equipment inspections, with no need for manual feeding at night.

Application of Liquid Feed in Global Pig Industry

Liquid feed accounts for approximately 30% of the total feed used in European pig farms: 30% in Germany, 20% in the United Kingdom, and 30% to 50% in Denmark, Ireland and the Netherlands. It is also being gradually adopted in Thailand, the Philippines and other Southeast Asian countries. It is believed that liquid feeding systems will be widely adopted by domestic pig farms and become the mainstream feeding mode in China’s pig industry in the near future.