Effect of Hut Design on Farrowing and Lactataion Performance of Pigs Housed in a Hoop Structure

Introduction

Economics drive profitability in hog production units. Inputs such as buildings and equipment are the second leading expense behind feed costs. Hoop structures offer a low cost alternative form of swine housing, however, production levels must be evaluated in any new system.

Published data for group housed sows during farrowing and lactation suggests mortality rates of 16-19% (Goetz and Troxler, 1995; Gustafsson, 1983; Cronin and Smith, 1987). These levels are much higher than those reported in modern confinement systems where sows are crated for the entire farrowing and lactation period. Modern farrow-to-wean farms strive to keep their pre-weaning mortality below 10% of live born piglets. The rates published in many group housed farrowing situations are at least double that of commercially acceptable levels. The historical move of sows from pasture systems (a group farrowing situation) to an indoor farrowing crate system stemmed from this problem of high preweaning mortality. It was discovered that restricting sow movements led to reduced crushing and, thus, the farrowing crate was borne. Today, the majority of sows are confined in crates for farrowing and lactation.

No published research is available on sow and piglet performance during farrowing and lactation in a hoop structure and, thus, the focus of this study was to evaluate performance parameters associated with different farrowing hut designs in such a system.

Materials and Methods

Animals in this study were bred and reared at the Moorman Swine Research Farm at the University of Illinois in Urbana-Champaign. Forty-eight primparous and multiparous crossbred sows were mated to Duroc sires and introduced as a group to the treatment pens within the hoop structure at approximately day 107 of gestation. Performance of the piglets was measured during a 21 day lactation period.

Equipment. Two different designs of hoop structure were used in this study (Span-tech, Houghten, Iowa and Coverall, Saskatoon, SK). Both buildings were 30ft wide by 84 ft long and were constructed of polyethylene fiber canvass stretched over a roof formed with metal pipes and had a 4 foot high wood sidewall. A removable door made of the same polyethylene canvass was present on both ends of the structure to facilitate natural ventilation. A concrete pad extended 20 ft into the building on the south end and a feeder (eight hole, Farmweld) was anchored in the center of the concrete pad. Two heated waterers (four hole, Mirafount) were situated on the concrete in each building. Outdoor wooden (Smidley, Marting Manufaturing, Iowa) and galvanized metal (Portahut, Storm Lake, Iowa) farrowing huts were used for the farrowing experiment. A roller door was designed to keep piglets inside for the first 7 to 14 days of life. The device was constructed of a smooth metal or PVC plastic cylinder mounted on a frame which was bolted to the door of the hut. The roller protects the sow’s udder as she passes into and out of the hut.

Trial Design. Forty-eight sows and their litters were used to evaluate the performance effects of two farrowing hut designs in a 2 X 2 factorial arrangement. Sows were selected and balanced across treatments for breed and parity. The sows were allotted to their respective treatments one week before farrowing. The treatment group had access to huts equipped with roller doors designed to keep piglets inside the hut for 10 to 14 days while allowing the sow free movement into and out of the hut. The control group had huts that had no roller door and, thus, the piglets were free to move out of the hut immediately after birth. The sows had access to six huts from one treatment group throughout the farrowing and lactation period. Sows were allowed free choice of hut but were moved if they farrowed in the aisle or on the concrete. Some females were locked in a hut during farrowing to prevent them from scattering their litters. During the extreme hot weather, farrowing sows were drenched by hand with buckets of cool water and a 4.5 ft portable fan with a mister was installed at the front of the hoop structure. The fan ran from 1200h to 2200h each day. The four groups of sows averaged 6 days between the farrowing dates for the first and last litter in each group and the piglets were processed after the last litter was born. The sows were removed from the building during processing to preserve the safety of the technician and piglets. The sows were allowed ad libitum access to a lactation diet that met or exceeded NRC (1998) recommendations. A creep area (2.8m x 5.1m) equipped with creep pellets was available for piglets from day 5 post-farrowing onwards.

Performance Measurements. Piglets were weighed at the time of processing and again at weaning. Number born per sow, number born alive, and number of mummies was recorded. Mortalities were recorded each day for each sow.

Results

The results of this study are presented in Table 1. Hut design did not influence the number of live piglets born per sow (13.1 vs. 12.0 piglets, for huts with roller and without roller, respectively, SE = 0.66, P > 0.05) or the number weaned per sow (5.3 vs. 5.1 piglets, for huts with roller and without roller, respectively, SE = 0.81, P > 0.05). High levels of mortality (60% of liveborn piglets) occurred within the hoop structure system. Hut design did not affect (P > 0.05) mortality rate. Piglets reared in the hut without a door roller had higher individual piglet weaning weights compared to those having a roller in the door (4.5 vs. 4.2 kg BW, for huts with roller and without roller, respectively, SE = 0.09, P < 0.02). Lighter weaning weights may have been due to the piglets in the huts with roller bars having reduced access to the sow relative to the piglets housed in huts without rollers. It is possible that the sow controlled of nursing frequency in the treatment group, whereas, the piglets controlled this behavior in the huts without roller doors, as they displayed more frequent udder stimulation. In order to fully explore this theory, a behavior study has been conducted and is in the process of being analyzed.

In summary, huts fitted with a roller on the door resulted in lighter piglet weaning weights, but did not reduce piglet mortality within a hoop structure system.

Conclusions

1. Mortality rates in this loose-housed system for farrowing and lactation were extremely high.

2. Hut design did not affect piglet mortality.

3. Installing a roller door in the entrance to the hut resulted in reduced piglet weaning weights compared to huts with no roller door, but had no effect on mortality.

Literature Cited

Cronin, G. M. and J. A. Smith. 1992. Effects of accomodation type and straw bedding around parturition and during lactation on the behavior of primiparous sows and survival and growth of piglets to weaning. Appl. Anim. Behav. Sci. 33:191-208.

Goetz, M. and J. Troxler. 1995. Group housing of sows during farrowing and lactation. Trans. Am. Soc. Agric. Eng. 38(5):1495-1500.

Gustafsson, B. Effects of sow housing systems in practical pig production. Trans. Am. Soc. Agric. Eng. 1983:1181-1185.

Tables and Figures can be viewed in PDF version.