Effects of precise temperature control on local heating energy saving of suckling piglets

Abstract: The temperature requirements of piglets can decrease with the increasing age in the breeding farm. In this study, the growth performance and behavior of piglets were monitored in real time, in order to explore the effects of precise temperature control on the local heating, and the energy consumption of heat lamps. Forty-eight stalls of piglets were selected from two test rooms of a pig farm in Hebei Province of China. Three groups were divided: four temperature gradients group with 2 ℃ for each gradient (Group Ⅰ), four temperature gradients group with 1℃ for each gradient (Group Ⅱ), and two-stage power group (control group) with 16 stalls in each group. The age of the piglets (21 days from birth to weaning) was divided into four periods, 1 to 3, 4 to 7, 8 to 14, and 15 to 21?days. The automatic system of temperature control was used to set the different temperature gradients. The temperature control system consisted of a touch-screen, a temperature sensor, a Programmable Logic Controller (PLC), and a silicon-controlled rectifier for voltage regulation. Control group was adopted as a manual switch with two push buttons of high and low (high and low indicated the heat lamp with 250 and 175 W power, respectively). In addition, a heat lamp (250 W) was placed for the local heating of piglets in each stall. The temperature under the heat lamps, growth performance, behavior of piglets, and the energy consumption of heat lamps were measured to calculate the carbon dioxide emission of energy consumption. The results showed that the average temperatures were 24.1 and 24.3℃ in the two test rooms, respectively. The average air temperatures were 30.5, 28.1, 27.6, and 26.1 ℃, respectively, under the heat lamp with the Group Ⅰ. By contrast, the air temperatures were 29.7, 27.9, 27.2, and 26.9℃, respectively, under the heat lamp with Group Ⅱ. The air temperatures were 31.4, 27.3, 27.7, and 27.8℃, respectively, under the heat lamp with a control group. There were no significant differences in the average daily gain among the three groups (P>0.05). The survival rates of suckling piglets were 96.7%, 96.8% and 96.7%, respectively. There was no cold stress in the three groups of piglets. Compared with the control group, the energy saving rate of Group Ⅰ and Group Ⅱ were 16.7% and 26.2%, respectively. The automatic system of temperature control recovered the cost only in two and one winters, when the temperature of the heat lamps was set, according to the Group Ⅰ and Group Ⅱ. In energy conservation, four temperature gradients can be expected to better control the heat lamps, compared with the two-stage power control for the local heating of piglets. The finding can provide the reference for the optimal strategy of precise temperature control on the heat lamp, in order to improve the economic benefits of the pig farm.