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Litter-Bed Pig House System: Caring for Both the Animal and the Environment
Shao-Yi Sheen
Division of Livestock Management
Livestock Research Institute (LRI), Council of Agriculture (COA)
112 Muchan, Hsinhua, Tainan, Taiwan ROC, 2005-12-01

Abstract

The litter-bed pig house, made up of a conventional concrete floor and a litter-bed area, serves a dual purpose: pig raising and pig waste treatment. It was developed by the Taiwan Livestock Research Institute (TLRI) to make full use of animal manure and exempt it from wastewater treatment. In the study conducted on the growth performance of pigs in the litter-bed pigpen, the pigs' growth was as good as those in the conventional concrete floor, be it for piglets or for growing-finishing pigs. As long as the litter was kept dry, the temperature of the litter-bed was maintained and the odor of the pig farms was controlled. The management of the litter-bed pig farm also paid great attention to animal and environment welfare.

Key words: litter-bed pig pen, Taiwan, animal waste disposal, pig waste treatment, litter

Introduction

Taiwan was first known to the western world as "Formosa," which meant beautiful island, rich in natural resources and abundant with varieties of plants and animals. However, since its people and their activities increased during the country's development, the harmonious relationship between man and the environment declined. The same has been true in the case of Taiwan's animal industry. It developed rapidly the past few decades, was transformed from backyard farming to sideline profession, and has transformed into intensive management-run mass production business. At the end of 2004, the number of animals raised in farms were as follows: cattle, 145 thousand head; pigs, 6.82 million head; goats, 249 thousand head; chicken, 108 million birds; ducks, 9.8 million birds; etc. (COA 2005). Such dense populations of animals inevitably resulted in the occurrence of pollution problems.

In Taiwan, the implemented environmental laws and regulations concerning animal waste disposal include the following: Environmental Impact Assessment Act, Water Pollution Control Act, Waste Disposal Act, Drinking Water Management Act, Air Pollution Control Act, and their implementation rules. The animal producers, especially the pig farmers, have to put great effort into animal waste treatment or they may be charged with a stiff penalty. Therefore, it is better for pig farmers to shift their management strategy from efficient and profitable management to an environmentally friendly management.

Generally speaking, the choice of disposal of animal wastes is highly dependent on the housing design and the method of waste cleaning used. Therefore, planning for the waste treatment scheme before constructing the animal house is advised. Through reduction, recycle, and recovery of the animal wastes, the management of animal farms can be more economical and pollution can be kept at a state of low or zero discharge. By doing so, the animal industry can be accepted as a healthy and environmentally friendly industry.

Litter-Bed Animal Houses

The litter-bed pigpen has a normal, conventional concrete floor where pigs can eat and rest and another part is covered with a bedding material to absorb pig manure. The pig house is constructed for dual purpose: pig raising and pig waste treatment. Such a layout can produce a manure-litter mixture that retains feces and urine in the confined area in the pigpen for a period of time. Once the pigs are sold, the manure-litter mixture is removed from the confined area and is composted to make organic fertilizer. This pig house is especially suitable for small pig farms, where wastewater treatment investment is not economical.

In brief, the litter-bed pigpen has two parts: 1) a 30-40 cm deep pit floor covered with a bedding to absorb the pig manure, and 2) a concrete floor for feeding and other activities. Rice husk and dry compost are the common bedding materials. The addition of probiotics or microbial products as bedding supplement is not required at all. Neither wastewater nor annoying odor is generated when enough litter-bed area is provided. Generally speaking, each finishing pig requires about 0.4-0.6 m2 x 40 cm (deep) of litter-bed space.

Layout of a Litter-Bed Pig Farm

TLRI researchers have been conducting studies on manure-bed pig houses since 1987 (Hong et al. 1989; Hong et al. 1990; Hong et al. 1994; Hong et al. 1995). The results showed that the average daily body weight gain, feed conversion ratio, and the survival rate of the piglets raised in the manure-bed pigpens were all superior to those raised in the conventional concrete-floor pig houses. In 1997, five conventional pig houses were remodeled to set up a complete litter-bed pig farm, including one breeding pig house, one farrowing pig house, two growing-finishing pig houses and one composting house ( Fig. 1(1408)).

The pig houses are situated on an east-west alignment to receive proper sunshine in southern Taiwan. The litter-bed pigpens can be simplified into two kinds: 1) ordinary litter-bed pig pens for boars, gilts/dry sows, and growers/finishers, though the required spaces for different pigs varied ( Table 1(1288)); and 2) farrowing litter-bed pigpens for farrowing pigs and weaners.

In the ordinary litter-bed pigpen, the concrete floor with a concrete wall is located on the northern side and the litter-bed with tubular fronts is on the southern side ( Fig. 2(1508)). The drinker is installed on the tubular fronts, while the feed trough is placed on the concrete floor. This layout helps train the pigs to dung on the litter-bed. The beddings are added to keep the water content of the litter at less than 40%. The dry beddings provide comfortable and clean air environment for the pigs. No daily wash is required. The rainwater and the spilled drinking water are collected separately from the pig wastewater. The tubular fronts can be rolled backward to the concrete floor when the dung-litter mixture needs to be cleaned out ( Fig. 3(1390)). The liquid waste from the farrowing house is collected in the storage tank and added to the litter mixture during composting. Therefore, this farm generates no wastewater.

The major difference between the litter-bed farrowing house and the conventional one is that two 10-cm-deep litter-beds are located on both sides of the farrowing crate ( Fig. 4(1217)). The beddings in the litter-bed can keep the newborn piglets warmer for them to grow healthier. The sow is moved to the farrowing house one week before delivery. At weaning, the sow is moved back to the breeding house. The weaned pigs stay in the farrowing house until six to eight weeks of age and then moved to the growing-finishing houses. This arrangement can prevent the weaned pigs from the multiple stresses of weaning, moving, and regrouping at the same time.

This type of pig house has many advantages. Its simple structure entails low construction and labor cost and no wastewater discharge. It is suggested that the operation of litter-bed pig farms be divided into three stages: dry and pregnant sows, farrowing pigs, and growing-finishing pigs.

Since a litter-bed pig farm needs no regular washing, sanitation and disinfection are particularly important. A routine, once-a-week parasiticide application for disinfection is needed.

Growth Performance of Pigs in the Litter-Bed Pig Houses

To investigate the growth performance of pigs, 257 hogs from 28 litters, produced by 14 sows sired by a Duroc (D) boar, were evaluated. Sows used in the study included five Landrace (L) females and nine offspring of Landrace sows crossed with Yorkshire boars (LY). The average daily gains of barrows and gilts from 70 to 150 days of age were 0.73-0.75 kg and 0.73-0.74 kg, respectively ( Table 2(1529)) (Sheen et al. 2001). Littering performances of sows were also evaluated. Litter size born alive, percentages of preweaning (3-4 weeks of age) survival, and percentages of piglet survival from 3-4 weeks to 70 days of age were 9.18 piglets/sow/litter, 97.7%, and 98.4%, respectively.

Hong et al. (1995) carried out pig-raising field tests in a farm located in Ur-Lueen Township, Yunglin County, starting from October 1994 to May 1995. The performance of the conventional slatted farrowing pens and manure-bed (filled with rice husks) farrowing pens were compared. Table 3(1281) shows that, when the piglets were five weeks of age, the average gain of live weight and percentages of piglet survival in the manure-bed farrowing pens were higher than those in the conventional farrowing pens, but they were not significantly different. This finding was similar to that of Hong et al. (1994).

The Impact on the Environment

The high temperature and the offensive odor generated from the litter-bed during the hot season are the frequent complaints on the litter-bed system. Controlling the water content of litter at less than 40% can solve both problems. The dry litter does not allow the microbes to carry out fermentation in the litter-bed. Fig. 5(1341) shows the temperatures of the top, center, and bottom litter compared with the ambient temperature. It was found that during the pig-raising period, the room temperatures were always higher than the litter temperatures, while the temperature of the top litter was the lowest. Thus, the pigs will not suffer from heat stress in the hot season.

The odor at the boundary of the litter-bed pig farm was also monitored for successive 10 months. The results showed that under proper management, the odor measurements at the boundary met the legal restriction, which is 50 for the agriculture and animal husbandry area ( Table 4(1302)). Regardless of the big varied background data, the odor-monitored results throughout the year were satisfied.

The relationship between odor emission and nitrification of litter material was also studied in litter-bed pigpens paved with rice husk and mature compost for bedding, and in an empty pigpen as control. The odor measurements of the bedding surface were 17-30, 167?117, and 203?145 for the control, compost, and rice husk group, respectively, while concentrations of NH3, H2S, and (CH3)3N in the center of the compost group's bedding were higher than those of the rice husk group. Monitoring the distribution of TN, NO3- and NO2- among different layers of litter bedding, the highest concentration was found in the bottom layer, the center layer next, and the bedding surface, the lowest for both experimental groups. Therefore, it was expected that the odor emission of the litter bed was related to the nitrification of the bedding in litter-bed pigpen. The measured pH, EC, TN, P, K, Cu, Zn of the compost group were higher than those of the rice husk group, even though the variation trends during the experiment period of the two experimental groups were similar. The concentrations of the rice husk group were higher than those of the compost group. Therefore, in addition to the rice husks, the mature and dry compost can be used as good beddings.

Composting the Litter

After the pigs are sold or when the litter-bed needs to be emptied of its litter, the tubular fronts are rolled backward to the concrete floor. The emptied litter mixture is then stacked for composting. The wind rows are turned once a week to supply air to the compost and to mix the compost more homogeneously.

In the study, from 45 days to marketing age, each growing-finishing pig consumed

44.9 kg of rice husks for bedding and generated 180 kg litter (contained 40.8% moisture). After 70 days of composting, the litter ripened into mature compost with 28.6% moisture, 69.8% organic matter, and 4.1% total nitrogen ( Table 5(1402)) (Sheen 2001). This compost is a good organic fertilizer.

Animal Welfare

In the litter-bed pig farm, daily washing is omitted. Thus the construction of wastewater treatment facilities is consequently not necessary. The pigs will not be bothered by the washing, enjoying the extra litter-bed area saved from the wastewater treatment. The rainwater and spilled drinking water collection devices help to keep the litter and the floor dry, and provide the pigs with a dry and comfortable environment.

The sow is moved into the farrowing house one week before delivery and is moved out at weaning. Thus, for each delivery, the sow is kept in the crate for only five weeks. In addition, the beddings in the farrowing house help to keep the newborn piglets warm. The not-so-humid environment in the farrowing house will contribute to the microbe control and healthy growth of the pigs.

Conclusion

The animal industry in Taiwan is faced with the double stresses of improving profit efficiency and ensuring environmental protection. To maintain the competitiveness of the business, animal farmers have to adjust their management strategy from being product-directed to creating the environment-efficiency balance and to build up a business that is cost-effective and low-discharge. The best strategy for this challenge is to follow the 4R principle _ reduction, recycle, recovery, and reuse. The litter-bed pig system was developed according to this principle. The results proved that it is not only about caring for good animal production, but also for the welfare of the animal and the environment. By this we can achieve a harmonious and sustainable animal business.

References

  • Council of Agriculture. 2005. Agricultural statistics yearbook.
  • Hong, C. M.; T. W. Lin; M. S. Lee; C. H. Su. 1989. Studies on manure-compost hog houses. J. of Chinese Soc. of Animal Sci. 18 (1-2): 99-110.
  • Hong, C. M.; T. W. Lin; M. S. Lee; N. T. Yen. 1990. Performance of growing-finishing pig raised in manure-bed pens. J. of Chinese Soc. of Animal Sci. 19 (3-4): 191-206.
  • Hong, C. M.; T. W. Lin; C. C. Cheng; M. S. Lee; N. T. Yen; Y. S. Cheng; C. Tai. 1991. Construction and management of manure-bedded pig houses. Special edition, Number 11, Taiwan Livestock Research Institute, Taiwan, ROC.
  • Hong, C. M.; N. T. Yen; M. C. Lee; G. S. Tsai; T. W. Lin. 1994. Performance of piglets on composting-manure farrowing beds. J. of Taiwan Livestock Res. 27 (1): 61-67.
  • Hong, C. M.; M. S. Lee; T. W. Lin; P. K. Lei; C. Tai. 1995. A field study of manure-bedded farrowing pens. Research report published by Taiwan Livestock Research Institute.
  • Hong, C. M.; C. H. Su; , B. Y. Wang. 1997. Research and development of manure-bedded pig houses. J. of Chinese Soc. of Animal Sci. 26 (Suppl.): 224.
  • Sheen, S. Y. 2003. The strategy of the management of the eco-animal industry — Turning the wastes into resources. In: Chou, C. H. and S. S. Yang (eds.), pp. 25-38, The challenges of agriculture in production, life and ecology. ISBN 957-01-5866-2. Taipei, Taiwan.
  • Sheen, S. Y.; C. M. Hong; M. T. Koh; C. C. Su. 1994. Swine waste treatment in Taiwan. FFTC Book Series No. 145/1994 pp. 87-97.
  • Sheen, S.Y.; C. C. Su; M. S. Lee; H. L. Chang; C. M. Hong. 2001. Study on the management model of litter bedded pig houses. Livestock Research 34,2: 69-78.

Index of Images

Table 2 Performances of Piglets and Hogs Raised in the Litter-Bed Pig Housesa, B, C

Table 2 Performances of Piglets and Hogs Raised in the Litter-Bed Pig Housesa, B, C

Figure 1 A Full View of the Litter-Bed Pig Farm.

Figure 1 A Full View of the Litter-Bed Pig Farm.

Figure 2 A Litter-Bed Pigpen for Breeding and Growing-Finishing Pigs.

Figure 2 A Litter-Bed Pigpen for Breeding and Growing-Finishing Pigs.

Table 4 The Odor Monitoring of the Litter-Bed Pig Farm

Table 4 The Odor Monitoring of the Litter-Bed Pig Farm

Figure 3 The Tubular Front Is Moved Backward for Litter Cleaning.

Figure 3 The Tubular Front Is Moved Backward for Litter Cleaning.

Table 1 Space Requirements for Different Types of Pigs in Litter-Bed Houses

Table 1 Space Requirements for Different Types of Pigs in Litter-Bed Houses

Figure 4 A Farrowing Pigpen.

Figure 4 A Farrowing Pigpen.

Table 3 Performances of the Manure-Bed and the Conventional Farrowing Pens

Table 3 Performances of the Manure-Bed and the Conventional Farrowing Pens

Figure 5 The Temperature Changes of Rice-Husk Litter in the Litter-Bed Pig House

Figure 5 The Temperature Changes of Rice-Husk Litter in the Litter-Bed Pig House

Table 5 Changes of the Constituents of the Litter during Composting

Table 5 Changes of the Constituents of the Litter during Composting

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