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                        TECHNICAL PAPER # 39
                        UNDERSTANDING SWINE
                          Vernon M. Meyer
                         Douglas Henderson
                        Technical Reviewers
                          Herman Pinkston
                         Dr. Eugene Snyder
                        Dr. Vaughn C. Speer
                1600 Wilson Boulevard, Suite 500
                  Arlington, Virginia 22209 USA
             Tel:  703/276-1800 * Fax:   703/243-1865
                 Understanding Swine Production
                      ISBN:  0-86619-251-4
           [C] 1985, Volunteers in Technical Assistance
This paper is one of a series published by Volunteers in Technical
Assistance to provide an introduction to specific state-of-the-art
technologies of interest to people in developing countries.
The papers are intended to be used as guidelines to help
people choose technologies that are suitable to their situations.
They are not intended to provide construction or implementation
details.  People are urged to contact VITA or a similar organization
for further information and technical assistance if they
find that a particular technology seems to meet their needs.
The papers in the series were written, reviewed, and illustrated
almost entirely by VITA Volunteer technical experts on a purely
voluntary basis.  Some 500 volunteers were involved in the production
of the first 100 titles issued, contributing approximately
5,000 hours of their time.  VITA staff included Betsey Eisendrath
as editor, Suzanne Brooks handling typesetting and layout,
and Margaret Crouch as project manager.
The author of this paper, Vernon M. Meyer, is an Extension Agricultural
Engineer with the Iowa State University of Science and
Technology.  The co-author, Douglas Henderson, is an Extension
Livestock Production Specialist working with the same institution.
The reviewers of this paper are all VITA Volunteers.   Herman
Pinkston has served in the Philippines as a Peace Corp volunteer
specializing in animal husbandry and agriculture.   He is currently
employed with the Defense Contract Administration in New York.
Dr. Eugene Snyder is a veterinarian, and has been involved in
swine breeding and production for many years.   Dr. Snyder also
served for two years as a veterinarian for the Peace Corps in El
Salvador and the Dominican Republic.   Dr. Vaughn C. Speer is the
Chairman of the Swine Nutrition Research Section, Animal Science
Department at Iowa State University, and has written over 200
scientific publications on swine nutrition and management.
VITA is a private, nonprofit organization that supports people
working on technical problems in developing countries.   VITA offers
information and assistance aimed at helping individuals and
groups to select and implement technologies appropriate to their
situations.  VITA maintains an international Inquiry Service, a
specialized documentation center, and a computerized roster of
volunteer technical consultants; manages long-term field projects;
and publishes a variety of technical manuals and papers.
       by VITA Volunteers Vernon Meyer and Douglas Henderson
Swine production provides red meat for the human diet, uses less
feed than is required to produce beef or lamb, and is also a
source of bides and cooking fat.   Swine are also scavengers, and
can make productive use of many materials that would otherwise be
Pigs (young swine of either sex weighing less than 120 pounds),
were domesticated in China as early as 4900 B.C.   Biblical writings
mention them as early as 1500 B.C., and there are references
to the keeping of swine in Great Britain in 800 B.C.
Today, swine are raised throughout the world.   Their numbers are
particularly high in countries that are heavy producers of corn,
barley, and potatoes.  Countries that have surplus dairy by-products
such as buttermilk and whey also produce many hogs
(domesticated swine weighing more than 120 pounds, raised for
market).  The only places where swine production is not suitable
are where religious law (as in Islam and Orthodox Judaism, for
example) or strong tradition forbid the consumption of pork.
Even in such places, small operations serving special markets are
sometimes permitted.
Climate is not generally a limiting factor except where it
threatens feed supply.  Swine are raised in both warm and temperate
climates, although young pigs must be kept warm, and sheltered
from weather extremes.
Swine production around the world is extremely varied.   Wild pigs
are hunted.  Single pigs are cared for and fed, to yield food for
festivities or for routine family fare.   Swine can be produced
efficiently in very small numbers for home or family farm use, or
in larger numbers for marketing.   Large-scale production is more
likely to succeed where cooperative marketing is possible.
The technology of swine production is well developed.   Feeding,
management, housing, health, and marketing systems vary greatly
within and between countries.   In parts of the world where labor
is cheap and capital is scarce, labor intensive systems tend to
be used, while production methods in industrialized countries
tend to be nore capital intensive.   Hogs in some areas are raised
primarily on forage, while elsewhere large numbers are produced
in total confinement without green feed.
There are many types, breeds, and systems of breeding.   Purebreds,
hybrids, and crossbreds furnish most of the world's pork
supply in various grades or quality.   Crossbreeding accounts for
about 90 percent of swine production in the United States and
Great Britain.
Swine production has many advantages:
o    Swine convert feed to meat more efficiently than cattle or
     sheep do.   A beef steer requires about nine pounds of feed
     to produce a pound of beef, a lamb requires about eight
     pounds, while a hog requires from four to five pounds of
     feed per pound of liveweight.
o    Swine are prolific, commonly producing two litters per year
     and from six to twelve pigs per litter.
o    Swine excel in yield of useable carcass compared to other
     animals that produce red meat.  Dressing yield is from 65 to
     80 percent for swine, but 50 to 60 percent for cattle, and
     45 to 55 percent for sheep and lambs.
o    Hogs can convert some wastes and by-products into meat.
     Examples are garden waste and some types of garbage.  (Garbage
     such as food and garden scraps should be cooked before
     being fed to hogs to help prevent the spread of disease.)
o    Very little labor is required.
o    It is possible to get by with a small investment for buildings
     and equipment.
o    Returns come quickly.  A gilt (young female swine) may be
     bred at eight months, and the pigs are ready for slaughter
     six months after farrowing.
o    Hogs are an excellent source of home-processed meats.  This
     is due to their ease of dressing and to the superior curing
     and keeping qualities of pork.
There are also drawbacks:
o     A hog's diet must rely more heavily on concentrates, which
      are expensive, than on roughage, which is cheaper.
o     Production requires fairly careful management to achieve
      good results.
o     Swine are very susceptible to numerous diseases and parasites.
o     Swine cannot utilize pasture as effectively as can cattle
      or sheep.
Type of Hog
During the late nineteenth and early twentieth centuries, family
farms in western Europe and North America preferred a hog that
produced large amounts of lard, since this was the common fat at
the time.  Now, however, people in many countries use other fats
for cooking, and so a meatier, more heavily muscled carcass, or a
leaner, bacon-type carcass is preferred.   The demand for cooking
fat in any country is a major factor in determining what type of
hog to raise.
Production Methods
Swine production methods today vary widely.   Very broadly
speaking, there are two approaches:   the pasture system, in which
the animals are allowed to range over suitable pasture and the
confinement system, in which the animals are kept in pens or
other enclosures.
Fifty years ago in the United States, confinement systems were
not possible.  Pasture feeding was necessary to provide the
nutrients that cereal grains did not supply.   Today,  protein and
mineral supplements can provide swine with optimal nutrition even
when they do not have access to forage.   This has made possible
the development of confinement systems.   In developed countries,
many swine producers have confinement buildings with controlled
ventilation and other environmental controls.   Automation has
replaced hand feeding.  Scientifically balanced diets are
provided for each stage in the life cycle.   Slotted floors have
come into common use.  Liquid waste disposal has improved, and
wastes are collected and applied to the land as fertilizer for
The result of these changes has been a dramatic speeding up of
production.  In the nineteenth century, it took eight to twelve
months to produce a market hog; today, a hog can be ready for
market in less than six months.   And it is now possible to
produce several crops of hogs per year; as many as four to six
crops are common on many farms.
Pasture System
Hogs are raised in the field on pasture with portable shelters.
This system is used if land is not needed for other crop
production.  The pasture may be rotated each year to break
disease and parasite cycles and to reseed the pasture.   This is
usually a warm-climate operation.   In the northern cornbelt of
the United States it is used for only one farrowing a year.  If a
second farrowing is produced, the pigs are finished in an
enclosed lot at the farmstead.
Resources, Materials, Equipment Needed
A fenced lot with portable feeders, portable waterers, and minimum
shelter with some bedding are the only resources needed.  An
A-frame or similar portable shelter is usually used for each sow
and litter.
Labor Needed
The labor required averages between 24 and 40 hours per sow and
Energy Use
No fans or heaters are used with this system, so the only energy
needed is that used to transport feed and water to the pasture
Cost per sow for one-litter pasture systems (1983 U.S. costs)
averages about $450 for buildings and equipment, and another $450
for breeding stock and operating costs.   For a two-litter pasture
system, costs would be about double.
Pasture systems require simpler skills and management than
confinement systems do.  Costs for pasture system shelter and
equipment are lower than those for the permanent facilities
involved in a confinement system.   Energy costs are also lower,
and the swine are less subject to crowding and social stress.
A pasture operation is also more flexible than a confinement
operation, expecially a confinement operation with elaborate
facilities.  As the price of corn rises in relation to the
market price of hogs, there comes a point at which it is more
profitable to sell the corn than to use it as feed for the hogs.
Simple production methods, in which the high-cost items are feed
and labor, allow the producer to respond as he sees fit in this
kind of situation, because his capital is not tied up in
elaborate facilities.
Fewer pigs per litter can be saved in the pasture system.
Weather problems are greater, since the hogs do not live in a
controlled environment.  It is harder to catch the pigs for
treatment, ear notching, and clipping of eye teeth.
Maintenance Requirements
Fencing, feeders, and shelters must be kept in good repair.
Typical Schedules
Gilts may be farrowed once a year--in warm weather, often on
pasture.  The investment in buildings and equipment can be very
small, but it is charged to only one group of sows and litters.
Or one group of sows may be farrowed twice a year, usually in
April and October in the Northern Hemisphere.   If one of the
farrowings is in cold weather, more investment in buildings and
equipment is required; costs are charged to twice as many litters.
Confinement seems to have the most benefit for small pigs, which
require a particularly stable and controlled environment to do
well.  Hogs are raised in buildings designed to provide the best
possible environment, to save labor, and to promote ease of
Two Pens
If pigs are farrowed, nursed, weaned, and started in one pen
until they reach about 60 pounds and 12 weeks of age, they can be
moved to a finishing unit for the next 12 weeks.   Four litters a
year can be raised this way in two pens in this type of facility
Some producers farrow three times per year--in temperate climates,
skipping a midwinter litter to leave more time for slower
pigs to reach 220 pounds and to avoid severe weather for farrowing
and very hot weather at the end of finishing.
An alternative is to put half of the sows into the stalls for
farrowing.  Litters with the largest pigs are weaned and moved
to a nursery pen when stalls are needed for farrowing.   The
second group of sows and litters stays in the stalls until
weaning.  About two litters are grouped into each nursery pen,
often after sorting by weight and vigor.
Four Pens
For large herds and six or more farrowings per year, it is common
to divide production into four stages, with a different enclosure
for each stage:  stalls where farrowing takes place and pigs are
field until weaning; nursery or starting pens; growing pens, for
pigs to weights between 75 to 125 pounds; and finishing pens, for
pigs up to market weight.
Resources, Materials, Equipment Needed
Buildings for Farrowing.  Farrowing in an enclosed building
allows the manager to control the environment.   Baby pigs must be
kept warm, dry, and free from cold drafts.   A newborn pig needs
an environment of about 90 [degrees] F, then is content with about a 2 [degrees]
drop per day to 70 [degrees] F.   The sow is more comfortable at about 60 [degrees] F.
To give mother and baby each its own preferred temperature, it is
necessary to provide supplemental heat in the creep area, which
is a pen constructed to exclude larger animals while permitting
young animals to enter and obtain feed.
Farrowing stalls. Farrowing stalls provide the best protection of
small pigs from injury (particularly for the first week or two)
and require less bedding, floor space, and labor than pens do.
It is more difficult to catch pigs in a stall.   The stall area may
be used to grow weaned pigs.
Many producers provide water and feed in each stall, while others
release the sows twice daily.   Feeding in stalls is especially
recommended for larger herds.   Farrowing stalls are commonly
built from one-inch lumber, 3/4-inch exterior plywood, or one-inch
galvanized pipe.  Solid barriers between the farrowing stall
pens can reduce drafts.  Oak or other hardwood is preferred, to
prevent animal damage.
Nursery Pens.  Nursery pens are used from the time the pigs are
weaned at three to six weeks of age.   The pigs are fed in these
pens until they reach a weight of about 40 pounds.   These pigs
need to be kept at temperatures of from 75 to 85 [degrees] F when first
weaned, depending on age at weaning.   Wire-mesh floors on raised
decks seem to provide the best environment.
Growing Pens.  The growing stage is the period between the nursery
stage and a weight of about 100 pounds.   Feed conversion is
highest at 60 [degrees] F, but this optimum environment for growing pigs
may require a large investment in buildings and equipment.
Growing pens may be:  pens in a separate building, pens in a
combination growing-finishing building, subdivided finishing
pens, or full-sized finishing pens.
Finishing Pens.  Finishing is the stage from pig weights of about
100 pounds to market size.  Pigs are finished on pasture,
shelter, and dry lot, open-front buildings, or incomplete
confinement.  Although finishing pigs can stand low temperatures,
fastest growth with least feed occurs at temperatures of about
55 [degrees] F and at relative humidities of 50-80 percent.
Labor Needed
For confinement systems, required labor ranges from 11 to 21
hours per sow and litter.
Energy Use
Confinement systems may require supplemental heat and energy to
operate ventilating fans.  Adequate insulation can minimize fuel
costs, and some natural ventilation can replace fans.
The higher cost of the confinement system makes it important that
the facility be fully used.  A multiple farrowing schedule should
be used to keep the buildings operating at design capacity, with
shutdowns only for major cleaning and sanitation.
Cost per farrowing space for a high investment confinement unit
(1983 U.S. costs) is $895 for buildings and equipment, and $600
for breeding stock and operating costs.
Where labor costs are high and capital is not too expensive, the
confinement system is advantageous because it substitutes capital
for labor.  It makes possible automatic feeding and a controlled
environment.  It uses less land than a pasture system does,
reduces the distance that feed and water need to be transported,
allows manure to be more efficiently collected for use as
fertilizer, and makes it easier to sort and pen groups for size
and uniformity.
Compared to pasture production, confinement production demands
greater management skill and a higher investment with less
flexibility.  Swine in confinement are also more vulnerable to
Maintenance Requirements
All automatic equipment, such as fans, heaters, and feeding
equipment, need routine maintenance.
Typical Schedules
Two or more groups of sows are each farrowed twice a year.
In temperate climates confinement buildings are essential for
this schedule.  Because the facilities are charged to many pigs,
the cost per pig may be the lowest of all possible schedules.
Capital, labor, land, feed, producer skills and preferences, and
climate are all factors influencing the choice of a system.
Four Common Choices
Four common production systems are compared here.   All four
systems produce pigs and carry them to market weight (around 200-240
1.  One-Litter Pasture System
In this program, gilts are farrowed once, then marketed.  All pigs
are raised and sold as market hogs, except for a new group of
gilts, which is saved back to continue the production cycle.  The
system makes good use of fenced cropland that is farmed in
rotation, and building and equipment investments are minimal.
However, it is risky, especially with regard to animal
performance and product price.   Predators and weather pose a
constant threat to young animals; and because each year's crop is
sold in one short period, there is always the danger of a
depressed market.  Therefore, a one-litter has an element of
risk, but needs supporting enterprises to provide income when it
2.  Two-Litter Pasture System
This system is suitable when you need a livestock enterprise to
add business volume or utilize salvage resources.   The system
operates on a six-month cycle, with saws farrowing in late winter
and late summer.  These farrowings can be scheduled to use labor
that is available during periods of little crop production
activity.  Essentials to success are herdsmanship skill and
cropland suitable for hog pasture.
3.  Low-Investment, Low-Intensity Confinement System
This system is most often used when the production of hogs is
secondary to the production of other crops.   The hog production
operation is maintained with seasonal labor and resources (feed,
buildings, fences, materials-handling equipment, etc.) that are
not needed for the primary activity.   Buildings are simple in
design, with a minimum of environmental control and labor-saving
devices.  Farrowings are usually scheduled to avoid the peak
labor periods for crop production.   A popular four-times-a-year
farrowing sequence in the Northern Hemisphere is December and
February, June and August.  Although the sow herd may glean grain
fields and graze available pasture, this confinement system does
not keep good land out of crop production.
4.  High-Investment, High-Intensity Confinement System
This system uses specialized buildings and equipment, including
self-cleaning (slatted or flushed) floors, liquid manure
handling, automatic ventilation, and automatic feed distribution.
Because this is a confinement system, it frees the land for the
production of other crops.  However if the large investment that
the confinement facilities involve is to pay off, the facilities
must be put to full use.  There must be at least six farrowings a
year, at regular intervals, and hog production must take
precedence over other crops in the allocation of available
resources.  This kind of high intensity farrow-to-finish
production is very demanding, and may be more manageable if the
unit is large enough to justify employing two or more operators.
The basic energy sources for swine are cereal grains:   Corn
(maize), milo (sorghum), barley, wheat, and their by-products.
Cereal grains are high in carbohydrates, as well as palatable and
easily digested.  But they usually contain less protein, minerals,
and vitamins than swine require; therefore, they must be supplemented
with other feeds to increase consumption of these nutrients
to recommended levels.  Although somewhat bulkier than the
cereal grains, grain by-products have much the same characteristics
as the grains from which they originate.
Corn contains less protein but more energy than the other
cereals.  The composition of corn, like that of all other
cereals, is influenced by variety, growth conditions, method of
harvesting, and storage.  Because of its abundance and readily
available energy, corn is used as the base cereal when the the
nutritional value of other cereal grain is given.   Milo, or grain
sorghum, is very similar in quality to corn and can completely
replace corn in swine rations.   Its energy value is about 95
percent of the value of corn (except for some bird-resistant
varieties, which may offer only be 80-90 percent of the energy
value of corn).  Table 1 shows the relative feeding values of a
number of feeds.
Table 2 lists feed requirements in terms of corn equivalent for
each of the four production systems described above.
Production systems vary in quantity and quality of labor required.
Pasture systems and low-investment confinement systems
tend to require hard physical labor and to expose the operator to
mud, manure, and inclement weather.   High-investment systems that
use slatted floors and handle manure as a liquid virtually eliminate
manual labor, but the work is confining, and odors may be
obnoxious.  Pasture systems provide margin for error:  the space
and green vegetation that they offer permit the operator to be
late or inexact and still avoid problems of nutrition,
cannibalism, and disease.  As intensity of production increases,
so does the required level of technical skill.   Operators of high
investment, high-intensity systems need to be skilled in
production scheduling, use of medications, and building and
equipment repair.  Table 3 shows amounts of labor required.
When the swine operator is intended to produce a significant
income, the minimum sizes shown in Table 4 are suggested.
                   TABLE 1.  Relative Feeding Values(1)
                             Metabo-       Relative                    Maximum recommended percent
                             lizable        feeding                        of complete rations(3)
                             energy        value vs.        Gesta-           Lacta-                Grow-
Ingredient (air dry)         cal/lb        corn(3)          tion             tion       Starter    finish            Remarks
Animal fat (stabilized)      3,550         210-220            5                5           5         10          High enerqy,
                                                                                                              reduces dust
Barley (48 lb/bu)            1,275          85- 95           80               80          25         85          Corn substitute,
                                                                                                              lower energy
Beet pulp, dried             1,020          70- 80           10               10           0          0          Bulky, high fiber,
Corn (yellow)                1,500           100             80               80          60         85          High energy,
                                                                                                              low lysine
Corn (high lysine)           1,520         100-105           90               90          60         90          Lysine analysis
Millet (proso)               1,227          90- 95           80               80          60         85          Low lysine
Milo (grain sorghum)         1,425          95-100(4)        80               80          60         85          Low lysine
Oats (36 lb/bu)              1,200          80- 90           70               15           0         20          Low energy,
                                                                                                              partial grain                                                                                                               
Oats (high protein)                            90            70               30           20        50          Low energy, partial
                                                                                                              grain substitute
Potatoes (220 D.M.)            370           20- 25           80               0           0          30          Should be cooked,
                                                                                                              low protein
Rice Grain                   1,074            75             40               15           0         20          Low energy, low
Rye                          1,300            90             20              20           0          25          Possible ergot
                                                                                                              low palatability
Spelt                        1,182            85             40               15           0          25          Low energy,
                                                                                                              low lysine
Triticale                    1,450          90- 95           80               80          20         85         Possible ergot
Wheat, hard                  1,500         100-105           80               80          60         85          Low lysine
Wheat, soft                  1,500          90- 95           80               80          60         85          Low lysine
Wheat, high protein          1,500         100-105           80               80          60         85          Low lysine
Whey, dried                  1,445         100-110            5                5          20          5          High lactose
                                                                                                                  content, variable
                                                                                                                  salt content
(1) Based on an air dry basis unless otherwise noted.   High
(2) Feedstuffs must be converted to an air dry equivalent of 88-90s
    dry matter to determine energy and substitution rates.  Complete
    data on all ingredients not available.
(3) When fed at no more than maximum recommended percentage of
    complete ration.
(4) Higher levels may be fed although performance may decrease.
(5) Some "bird resistant milos" are 80-90s vs. corn.
         Table 2.  Feed Requirements and Feed Conversion Rates
                     for Various Pork Production systems(*)
Feed Conversion                Feed per Unit of Production
 Production System       Bushels of Corn      Pounds of Pur-     Pounds Feed per
                           Equivalent         chased Feed        cwt. Produced
                             Per Sow Unit                      Per Wt. Gain
One-litter pasture         100                1050                410
Two-litter pasture         202                2350               400
Low-investment             203                2495                406
confinement system
High-investment            197                2550                400
confinement system
(*) Relative feeding values of some other feedstuffs are given in
the following table.
   Table 3.   Estimated Labor Requirements in Swine Production
                                                     Hours of Labor per
                                                     Unit of Production
Production System                                     Direct         Total
                                                     per sow unit
One-litter pasture system                             12             16
Two-litter pasture system                             36            48
Low-investment confinement system                     34            45
High-investment confinement system                    22            28
      Table 4.   Suggested Size of Swine Production Operations
                                  Number of          Pigs Produced
                                    Sows              per Year
One-litter pasture system             50                 335
Two-litter pasture system             25                 375
Low-investment confinement            60                 900
High-investment confinement          100                1500
Choosing a market is one of the important decisions a hog
producer must make before sale of slaughter hogs.   The market
selected may affect income and profitability.
Prices vary among markets.  Marketing costs, such as selling
charges, transportation, also vary.   Shrinkage, or the difference
between the original weight of livestock and that after it has
been prepared for market, will also affect the price.   Consequently,
hog producers need to be aware of alternative markets and to
choose the one which yields the greatest net return.
In the United States, about 70 percent of the nation's hogs are
sold by producers themselves.   That is, the producer negotiates
directly with a buyer, and the price is established in the direct
negotiation.  The main advantages of direct marketing from
producer to packer are that hogs are farm fresh, handling and
shrinkage are kept to a minimum, and transportation costs are
Some producers, about 29 percent in the United States, choose to
sell through public markets.   Producers who choose this method
may feel they themselves do not have sufficient skills to
negotiate with buyers, or they may want to support public markets
for the good of the industry.
Marketing Cooperatives
Some producers choose to market as a group, called a marketing
organization.  The basic purpose of these marketing organizations
is to negotiate either higher base prices or higher quality
premiums than are generally paid for hogs.   The marketing
organization usually agrees to supply the slaughter plant with a
specific number of hogs either daily or weekly.   Some unique
techniques for evaluating hog quality have been developed by
these organizations.  One group bases hog premiums on a sample
cut-out of a producer's hogs rather than individually evaluating
each hog or group of hogs as they are marketed.
The major advantage of cooperative marketing organizations is
that they can reduce buyer procurement costs while bettering the
bargaining position of producers, thereby improving net returns
for both seller and buyer.  Cooperatives have often been able to
tailor their marketing program to the needs of the producers, and
at the same time to supply buyers with the type of hog desired.
What building materials are available locally will influence the
choice of construction.  The type of feed and bedding available
will determine some of the equipment and facility to include in
the operation.
Maintaining animal health is one of the biggest problems of pork
producers in the United States.   A good program of sanitation and
preventative medicine is advisable.
With high-intensity confinement systems, cash flow can also raise
difficulties.  Good financial planning is a must when considering
this type of facility.
Appendix TABLE 1.  Pasture Space depends on Rainfall and Soil
     10 gestating sows per acre
      7 sows with litters per acre
     50 to 100 growing-finishing pigs per acre
               Appendix Table 2.  Shade Space
     15-20 feet    2/sow
     20-30 feet    2/sow and litter
         4 feet    2/pig to 100 pounds
         6 feet    2/pig over 100 pounds
               Appendix Table 3.  Waterer Space
     Minimum of two waterers per pen
     Pig (12-75 pounds):  10 pigs per waterer
     Pig (75-220 pounds):  15 pigs per waterer
      Appendix Table 4.  Floor and Lot Slopes
Slotted floors:  usually flat
Solid floors:
Farrowing Stalls:  1/4" - 1/2" per foot without bedding
                   1/4" per foot with bedding
     1/2" per foot without bedding
      1/4" per foot with bedding
Paved lots:  1/2" per foot
Paved feeding floors:
     Indoors:   1/4" per foot
     Outdoors:   1/2" per foot
Building alleys:
     1/2" per foot crown or side slope
     1/8" per foot to drains
Appendix Table 5.  Per-pig Space Recommendations for Enclosed
Pigs                   Weight Pound          Area foot 2
Farrowing stalls a       12-30                2-2 1/2
Nursery pens b           30-75                   3-4
Growing pens b           75-150                   6
Finishing pens b        150-220                   8
a Avoid concrete slats, slats over 2" wide, and partly slotted
  floors for prenursery pigs.
b For slotted, flushed, or scraped floor.
               Appendix Table 6.  Shed with Lot
    More lot area is often provided to facilitate manure drying.
                               Weight         Inside         Outside
                               Pound         ft /hd         ft /hd
Nursery pig                    30-75            3-4             6-8
Growing/finishing pig           75-220          5-6           12-15
Gestating sow                    325             8              14
Boar                             400             40              40
Sow in breeding                  325            16              28
  Appendix Table 7.  Animal Sizes, Pen Capacity, and Stall Sizes
                         Solid     Totally or Partly
Breeding       Weight    Floor        Slotted Floor      Animals    Stall
 Swine          Pound     ft             ft              per Pen      Size
  Gilts        250-300       40            24             up to   6
  Sows         300-500       48            30             up to   6
Boars         300-500      60             40                1       2'4"x 7'
  Gilts        250-300       20            14               6-12     1'10"x 6'
  Sows         300-500       24            16               6-12     2'0"x 7'
a Or flushed open gutter.  Open gutter not recommended in breeding
     because of slick floors.
                    Appendix Table 8.  Feeder Space
Sows:  1'/self-feed sow, 2'/group-fed sow.
Pig (12-30 pounds):      2 pigs per feeder space
Pig (30-50 pounds):      3 pigs per feeder space
Pig (50-75 pounds):      4 pigs per feeder space
Pig (75-220 pounds):   4-5 pigs per feeder space
                Appendix Table 9.  Water Requirements
Animal Type                               Gal/hd/day
Sow and litter                                 8
Nursery pig                                   1
Growing pig                                    3
Finishing pig                                  4
Gestating sow                                  6
Boar                                           8
               Appendix Table 10.  Ventilation, cfm/hd
                                  Cold             Mild          Hot
                 Weight          Weather          Weather        Weather
                 (pounds)         Rate             Rate           Rate
Sow and litter     400             20               80           500
Prenursery pig    12-30             2               10             25
Nursery pig       30-75             3               15             35
Growing pig       75-150            7               24             75
Finishing pig    150-220           10               35            120
Gestating sow      325             12               40            150(*)
Boar               400             14               50            300
(*) 300 cfm for gestating sows in a breeding facility.
               Appendix Table 11.  Slot Widths
     For slotted floors.  Wire mesh, metal, or plastic slats
             preferred in farrowing and prenursery.
                                       Slot Widths    Concrete Slat
                                         inches      Widths (inches)
Sow and litter                              3/8              4
Prenursery pig                              3/8        Not Recommended
Nursery pig                                  1               4
Growing-finishing pig                        1              6-8
Gestating sows or boars:
  Pens                                       1              6-8
  Stalls                                     1               4
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     Printers and Publishers, Inc., 1970.
Krider, J.F., J.H. Conrad, and W.E. Carroll.   Swine Production.
     New York:   McGraw-Bill Book Company, Inc., 1982.
Iowa State University.  Life Cycle Swine Nutrition.  Pm-489.  Ames:
     Iowa State University, 1982.
Iowa State University.  Pork Industry Handbook.  Ames:  Iowa State
     University, 1983.  See sections on:
     Production (10 fact sheets)
     Breeding and Genetics (4 fact sheets)
     Herd Health (19 fact sheets)
     Housing (21 fact sheets)
     Marketing (7 fact sheets)
     Management (4 fact sheets)
     Nutrition (10 fact sheets)
     Pork and Pork Quality (2 fact sheets)
     Reproduction (6 fact sheets)
     Waste Management (9 fact sheets).
Midwest Plan Service.  Swine Housing and Equipment Handbook.  Ames:  Iowa
     State University, 1983.
Thornton, Keith.  Practical Pig Production.  Suffolk.  Farm Press
     Limited, 1978.