Using hovers in the farrowing room to save energy
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- Using hovers reduces the use of fossil fuel energy in farrowing facilities.
- Hovers must meet the thermal requirements of piglets, especially during the first 2 to 4 days after birth. Hovers must also make up for reduced room temperatures.
- Sows housed with hovers increased their feed intake during lactation. But reproductive performance, measured by the weaning to estrus interval, didn’t improve.
Hover management tips
- Provide at least 1/2 square foot of hover floor area per piglet.
- Construct hovers of durable and washable materials.
- Provide a hover temperature of 85 degrees F during the first 2 or 3 days after birth.
- Continually reduce additional heat in the hover steadily after the critical first few days. Once the pigs are 1 to 2 weeks old, no supplemental heat should be provided to the hover.
What are hovers?
Hovers are simple, solid partition enclosures in farrowing crates or pens that piglets have free access to. A few commercial companies sell hovers for use in farrowing, but most hovers are homemade. Common building materials include:
- Rigid board plastic
Synthetic materials are easier to clean and are thus the most popular.
At the University of Minnesota's West Central Experiment Station, researchers studied hover usage. Over a one-year period they monitored energy consumption, air temperature and pig performance in farrowing rooms with and without hovers.
One of two identical 16-crate farrowing rooms was equipped with a traditional 250-watt heat lamp mounted over a side creep area of each crate. This control room was maintained at a target temperature of 75 degrees F to mimic conditions of Minnesota farrowing facilities.
The other room had a target air temperature of 65 degrees F. In this room each crate was equipped with one of four slightly different hover styles. The hovers
- Provided an 18-inch by 36-inch lying area
- Were constructed of "stokboard" or recycled plastic
- Had a 100-watt light bulb or electric heat mat as its heat source
- The study included a total of seven lactations. It started with a farrowing group in late spring, continued through the year and ended with an early spring farrowing.
On average, the hover room was only 5 degrees F cooler than the control room during cold weather conditions. Even with this small difference in temperature, the total electrical and natural gas usage for the hover room was much less than the control room (table 1).
Table 1. Total Electrical and Natural Gas Usage
|Electrical Usage (KWH)||Natural Gas (cu. ft.)|
Overall the hover room used 43 percent less electricity and 46 percent less natural gas (45 percent less total energy) compared to the control room. Most of this energy savings occurred with the last four farrowing groups during periods of cold outside temperatures (late fall to early spring).
Piglet survival was slightly less in the hover room (88.4 percent) than in the control room (93.5 percent). But, many factors could have influenced this difference. Both survival rates were good compared to industry standards (80 percent).
Since we consider piglet survival rates above 90 percent excellent, it may not be reasonable to expect hovers to further improve piglet survival. One may speculate that hovers would maintain, if not improve, piglet survival rates with marginal facilities and management.
During lactation, sows in the hover room ate one pound more of feed daily than sows in the control room. Increased feed intake was likely a result of the sows not being too hot. These sows had greater weights and backfat depth at the end of lactation than sows in the control room. Even though hover room sows were in better “condition” at the end of lactation, there was no difference in weaning to estrus interval when compared to sows in the control room.