Economics of Gestation Housing
Introduction
The economics of various methods for housing gestating sow has received very little attention by the pork industry. The most common method for housing gestating sows is indoors in individual stalls. The major reasons for using individual gestation stalls are: (1) a worker can more easily manage a larger number of sows with respect to feeding, vaccinating, mating, moving individual animals, etc., (2) physical aggression between sows is reduced, (3) a worker can more easily control the environmental aspects “needed” by the sow, (3) more sows can be housed in a smaller area, (4) overall hygiene of sows is improved due to better control of the dunging area, and (5) reproductive performance of the herd is enhanced per sow inventoried.
There is little doubt that gestation housing systems in the future will have to meet the welfare requirements of the sow and production standards desired by pork producers. The integration of welfare and production standards will be challenging.
Objective
Describe a computer model that can be used to evaluate the impact of various group-housing systems for gestating sows.
Background
It has been suggested that the requirements of the sow are “freedom” from malnutrition, thermal discomfort, physical discomfort, injury, diseases, fear, stress and suppression of normal behavior. The suggested requirements for the pig producer are high biological performance, low labor input, ease of management, reasonable operating costs, acceptable capital cost, and acceptable financial return. Welfare concerns can be addressed in a well-designed and managed group-housing system; however, all welfare concerns cannot be eliminated.
The major goal of an owner of a sow farm is to maximize sow productivity. Therefore, a housing system that has negative impacts on reproductive performance is to be avoided. Many factors influence the reproductive performance of sows (genetics, health, environment, geographic location, worker skill, management, etc.); thus, the housing system plays an important but not an exclusive part on the reproductive performance of sows. Although a number of studies have been published comparing sow performance in different housing systems, care must be taken when interpreting data generated from records gathered from several different farms. Most farms have only one system for housing sows; thus, a direct comparison between housing systems is confounded (not able to determine true effects) with farm effects.
One method to evaluate the possible economic effects of various biological and building construction aspects on a gestation housing system is to use a computer model. This paper briefly describes a computer model that can be used to evaluate the impact of various group-housing systems for gestating sows and management procedures on the cost of the gestation phase per pig weaned. The values used in the below figures are examples only to demonstrate how the template works. Pork producers will need to work with their contractors and consultants to obtain a realistic value for their situation.
Remodeling to replace stalls with group-housing
A vast number of different scenarios can be generated for converting an existing breeding-gestation facility into a group-housing environment. The first part of the model allows the user to briefly describe the buildings being evaluated (Figure 1). Some remodeling projects will most likely require the construction of additional buildings to meet certain welfare concerns. This model allows the user to add buildings. Other remodeling projects might require additional buildings; however, additional buildings will not be constructed due to the possibility of a person not wanting to go through the environmental permitting process. The second part of the model allows the user to enter annual ownership costs and variable costs for the breeding-gestation facility. The annual ownership factors for this model include depreciation on building structure, depreciation on equipment, interest on building and equipment (opportunity costs), repairs on building and equipment, taxes on building, insurance on building, and insurance on equipment. The annual variable cost factors for this model include the following factors for the breeding-gestation phase only: labor, feed, utilities, fuel, oil, veterinary services, vaccines, health supplies, semen and AI supplies, depreciation on breeding herd, interest on breeding herd (opportunity cost), insurance on breeding herd, operating loan payment of principal, and operating loan payment of interest. The third part of the model allows the user to evaluate the effect of farrowing rate and litter size on the cost of the gestation-breeding phase per weaned pig.
Figure 1 indicates an example of a spreadsheet for entering the data into the annual ownership cells and annual variable cost cells. The user can enter “known” values directly into each cell or calculate a value to enter into each cell.

Figure 1. Spreadsheet for remodeling a breeding-gestation facility. Input values are only examples to demonstrate how the template works.
Figure 2 indicates an example of the various types of values that can be calculated. This function allows the user to evaluate numerous “what if” scenarios. It is beyond the scope of this paper to discuss in detail all the various aspects of the model. The reader can easily observe in Figure 2 the types of input that can be entered by the user.

Figure 2. Spreadsheet to calculate various input values for remodeling. Input values are only examples only to demonstrate how the template works.
New group-housing gestation facility
The model to evaluate the influence of a new breeding-gestation facility on the cost of the breeding-gestation phase per weaned pig is essentially the same as the previously described model. This model allows the user to evaluate two options simultaneously (Figure 3). The various types of aspects that can be calculated for each scenario are indicated in Figure 4.

Figure 3. Example of calculations for two options when using new breeding-gestation facilities. Input values are examples only to demonstrate how template works.

Figure 4. Spreadsheet to calculate various input values for two options of a new gestation facility. Input values are examples only to demonstrate how template works.
New hoop-structure gestation facility
The model to evaluate the influence of hoop breeding-gestation facilities on the cost of the breeding-gestation phase per weaned pig is essentially the same as the model described for the remodeling project. This model allows the user to evaluate two options simultaneously (Figure 5 and 6). Some of the options that might be evaluated are whether the sows should be fed inside the hoop in feeding stalls or fed individually outside the hoop in a shared feeding area. The number of sows per hoop is definitely decreased when the sows are fed individually inside the hoop. However, additional labor is required for feeding when sows have to be moved to a specific feeding area. These computer models are available by contacting the National Pork Board.

Figure 5. Computer template to evaluate the influence of hoop structures on cost of breeding-gestation phase per pig weaned. Input values are examples only to demonstrate how the template works.

Figure 6. Spreadsheet to calculate various input values for two options of a hoop facility. Input values are examples only to demonstrate how template works.
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Information developed for the Pork Information Gateway, a project of the U.S. Pork Center of Excellence supported fully by USDA/Agricultural Research Service, USDA/Cooperative State Research, Education, and Extension Service, Pork Checkoff, NPPC, state pork associations from Iowa, Kentucky, Missouri, Mississippi, Tennessee, Pennsylvania, and Utah, and the Extension Services from several cooperating Land-Grant Institutions including Iowa State University, North Carolina State University, University of Minnesota, University of Illinois, University of Missouri, University of Nebraska, Purdue University, The Ohio State University, South Dakota State University, Kansas State University, Michigan State University, University of Wisconsin, Texas A & M University, Virginia Tech University, University of Tennessee, North Dakota State University, University of Georgia, University of Arkansas, and Colorado State University.