Optimal design and test of electromechanical control system of automatic feeder for nursing sow

Abstract: With the rapid development of large-scale and intensive breeding pig farms in China, the demand for digital intelligent feeding equipment has been increased. In order to realize precise feeding, and to meet the requirements of small intake with more times and dynamically adjusting feed intake based on lactation days, one automatic electro-mechanical feeding control systems of lactating sows was designed in this study. In the system, the electro-mechanical systems, wireless network technology, mobile Structured Query Language Lite network database, and electronic data interchange were integrated with feed intake prediction models of lactating sow nutrient requirements. This intelligent feeding system included main parts of feed supply line, buffer feed bin, feed level control tube, feed level control hand shank, feed level viewing port, feeding control line tube, screw conveyer, center control integrated box, laying-off trigger, feed containing groove and feed flowing tube. The system integrated predetermined ration intake prediction models of nursing sows into microprocessor memory, and combined wiper motor’s precise electronic control technology to realize the precise control of diet feeding. Results showed that the total residual of daily feed for each sow was less than 50 g. In the system, the level indicator and artificial observation hole in storage silo were used to keep feed fresh and to reduce arch, and the advised feed storage was 10 times as much as the predicted daily feed intake for sows in early lactation; Besides, the predefined dynamic feeding system could meet the requirement of feed intake by the 28 days lactating sows, and the feed intake curve was converged to the logarithm curve. A 28-d feeding experiment was conducted with a total of 531 piglets divided into 1 test group and 3 control groups. Each group had farrowing parities of 30, 36, 12, and 20 respectively. The pigelets were fed with the pre-set feed amount calculated by the feed intake prediction models in system for 4 times per day with ratio in feed of 30%, 25%, 25% and 20%, The results demonstrated that the piglets in test group had more feed intake (P<0.05) and higher average daily gain (P<0.01) compared with other 3 control groups. Taking the convenience of installation, trough clearing and feed ingestion into consideration, the install height of the laying-off trigger was suggested to be about 10 cm beyond the bottom of feed trough. This height is very convenient to install the feeding equipment and to connect with the related software systems. In conclusion, the designed electronic automatic feeding system of lactation sows adopts electro-mechanical integrate system and can work without sensors and electronic identification system such as Radio Frequency Identification Device. It is easy to operate and maintain, and feasible for use in common breeding sow farms. Additonally, it takes lower cost compared with expensive import devices as USA Osborne, France Elistar and the Netherlands Velos sow feeding devices, and thus is suitable for small and medium sow breeding farms. However, more studies are needed to verify the sows’ feed intake characteristic and weaning piglets’ performances, and to evaluate the performance of the proposed intelligent feeding system based on indicators such as estrus returning rate and survival rate of commercial pigs in life cycle of pigs.