An effective operations manual can help barn staffs keep production facilities running smoothly.

Pork producers commonly invest hundreds of thousands of dollars in a production site, yet give little thought to sitting down and drafting an owner's manual that will ensure it operates as efficiently as possible. Such an owner's manual, for a production site or series of buildings, would contain the following chapters:

Chapter 1: Operating characteristics of the heating and ventilation system.

Chapter 2: Feed system operation, including feeder settings.

Chapter 3: Water system operation.

Chapter 4: Emergency operation procedures.

Chapter 5: Repair schedules and seasonal settings.

Note that the idea of an owner's manual does not detail the many management issues associated with daily care of the pigs, such as identification and treatment of sick pigs, nutritional regimens, vaccination schedules, marketing of pigs, etc. Rather, the manual should detail the many issues that will allow the day-to-day operation of the facility to run smoothly.

Let's take a closer look at the contents of each chapter:

Chapter 1 — Heating and Ventilation Systems

Most likely, there is no detailed explanation of how or why the various ventilation system components were chosen, or a detailed listing of the capacities of those components, or the most common settings for the ventilation controller.

Armed with fan- and facility-specific information, it is possible to predict how a ventilation system will respond to various pig sizes, pig densities and changing seasons.

Assuming insulation values of R=30 for ceilings and R=3 for sidewalls, combining pig heat production estimates with facility heat loss equations make it possible to create Table 1. The balance point temperature in the table lists the estimated incoming air temperature at which heat production equals heat loss via the ventilation system and facility perimeters, walls and ceiling at various combinations of pig weight and room temperatures.

For pigs weighing 50 lb., if the set point of the controller is 70°F, and the first stage variable-speed fan has the minimum speed set to ventilate at 5 cfm/pig (two 24-in. pit fans in a 1,200-head facility), the room is in balance when the incoming (outside) air temperature is 23°F. If the incoming air temperature is cooler than this, heat must be added or the room temperature will gradually decline.

Conversely, if the incoming air temperature is higher than 23°F., the ventilation system will gradually increase the amount of air removed (cfm), while the room temperature rises.

When the stage 1 fan(s) run at 100% speed (often 10 cfm/pig), the room temperature is 2°F higher (bandwidth setting in the controller) than the set point and the incoming air will now be approximately 45°F.

Bandwidth is used with variable-speed fans to define the number of degrees of temperature change necessary for the fan to go from the minimum speed to full speed. A common winter setting is 2°F, which means the fan increases speed from the minimum to the maximum as the room warms up 2°F. When the fan is operating at full speed, the room temperature is 2°F warmer than the set point temperature.

As Table 1 illustrates, one of the biggest ventilation challenges in many wean-to-finish facilities is getting the ventilation rate low enough for pigs weighing 25 lb. or less. The balance point changes from 22°F to 45°F as the ventilation rate increases from 2.5 to 5 cfm/pig for 25-lb. pigs. At the 5-cfm/pig rate, this means heat must be added either as room heat or supplemental zone heat whenever the incoming air is colder than 45°F vs. heat additions at 22°F with 2.5 cfm/pig.

In addition, consideration must be given to humidity levels in grow-finish facilities. Table 2 offers some guidelines for managing ventilation rates during cold weather.

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