From 2007 to 2012, the average number of piglets born and piglets born alive for the US swine operation increased by 1.1 and 1.2 piglets per sow per farrowing event, respectively. However, increase in average number of piglets weaned during the same time period was 0.8 piglets per sow per farrowing event; and the pre-weaning mortality increased from 14.2% to 15.5% (Stalder, 2013). The preweaning mortality rate, coupled with the increased birth rate, means that 1.9 piglets per litter born alive are lost before weaning. These mortality figures stem from the challenges in meeting the different thermal, space, and behavioral needs of the sow and piglets in a production system that requires specialized herd management. Swine farrowing operations face the unique challenge of maintaining two distinct thermal environments in the same facility. Piglets require a dry, draft-free environment at 32.2-35°C (90-95°F), while sows prefer a comfortable temperature of 15.5-18.3°C (60-65°F) (MWPS, 1983). To meet these two needs, the room temperature is often maintained at 18.3-23.9°C (65-75°F) range and localized heating is provided to the piglets. There are two main methods of localized heating in the U.S. swine industry, heat lamps and heat mats. The goal of the localized heating is to draw the piglets away from the sow when not nursing to avoid mortalities due to being laid or stepped on. Because the cost of maintaining a sow through breeding, gestation and farrowing is generally fixed and independent of litter size, a change in preweaning mortality rate resulting in an extra pig per litter weaned approximately equates to an 11% reduction in fixed cost. Reducing prewean mortality by a small amount will have a significant economic impact on the swine industry. Improving energy efficiency in localized heating is another important factor that will affect the production bottom line as farrowing is the most energy intensive phase of the production cycle.
The objective of the study reported here was to quantify and compare the effects of localized heating type – mat vs. lamp with regards to piglet mortality, rate of gain, heat source utilization and electric energy use in swine farrowing rooms.
A 4,300-sow capacity breeding/gestation/farrowing facility (PIC genetics) in central Iowa was used in this study. The farrowing portion of the facility consisted of two buildings with nine farrowing rooms each. Three farrowing rooms, designated as Room F1, Room F2, and Room F3, were selected. Each room had four rows of ten farrowing crates. The rooms were filled and weaned within 3 to 4 days of each other. Two rows of crates in each room used a 125 W heat lamp suspended over a 2 ft × 4 ft black rubber mat. The rubber mat was shared between two crates, giving each crate 4 ft2 of mat area. The remaining twenty crates in each room used 2 ft × 5 ft Stanfield heat mats (290W, Osborne Industries, Osborne, KS, USA). The heat mats were shared between two crates which provided each crate with 145W over a 5 ft2 area. The lamps were controlled (on/off) with the room’s environmental controller. The mats were controlled with a separate control system that varied the power to the mats based on room temperature. Power usage of each heat source for each room was monitored with an electric meter.
All litters were weighed on day 1 or 2 post parturition. Randomly selected litters were weighed at intervals of 4 to 6 days to develop growth curves. All litters for each heat source type were weighed together at weaning using a drive-on truck scale. Other production data, such as mortality numbers and causes, number of piglets born alive, and number of piglets weaned, were recorded by the farm personnel. Piglet utilization of heat sources was monitored with infrared thermography for 24-hr periods at 4 to 5 d intervals during lactation. The thermographs were analyzed to determine heat source usage by the piglets.
