Cold housing is the
recommended system for raising replacement animals. Cold housing building systems
provide a dry and draft-free environment in winter, and wind ventilation and
shade in summer. The building is usually uninsulated and has natural
ventilation designed as an integral part of the building. Indoor temperature
follows outside temperature very closely.
Advantages of a cold
housing are:
Ø Less expensive to build.
Ø Less expensive to ventilate and heat.
Ø Better disease control.
Ø During cold weather, disadvantages of a cold
housing are:
A warm housing system
is less desirable for raising replacements. Typically environmentally
controlled systems are improperly managed resulting in health and growth
problems. The buildings are typically insulated heavily and a controlled
mechanical ventilation system delivers fresh outside air. Properly designed
inlets allow fresh outside air to be evenly distributed throughout the entire
structure.
Design mechanical
ventilation systems in calf barns to provide minimum continuous exchange of
air, Table 7. Because the number of calves and young heifers
in a facility vary, design mechanical ventilation systems for a range of
stocking rates.
Calves and young
heifers are very susceptible to respiratory illness and other diseases. Keep
calves less than two months old in clean, dry, draft-free facilities with
adequate space, bedding and fresh air. Separate calves to reduce disease
transfer from nose-to-nose contact. Separate calf groups from older animals to
minimize exposure to disease organisms. Keep calves in individual pens in an
enclosed building or individual hutches until weaning. After weaning they can
be moved to small group pens.
Calf hutches have proven to be an excellent
way to house calves. Only one calf occupies each hutch. Typical hutches are
4'x8'x 4'. Fig 2 illustrates plywood
construction. Leave one end of the hutch open and provide a wire fence
enclosure so the calf can move outside. Optional tethers can be used where
predators are not a problem. Seal tightly all other sections of the hutch, except
for the front and bottom, to reduce the wind blowing through the hutch in
winter. During summer, the rear of the hutch can be blocked up 6" to allow for cross ventilation or design an opening in the rear of the
hutch with a tight fitting door.
There are also a
variety of prefabricated plastic/fiberglass hutches on the market. Hutches made
of a translucent material require shade in summer. Summer shade reduces heat
stress on all types of hutches. Provide enough shade to allow hutches to be
moved.
Face hutch fronts south or east to provide draft
protection during winter and sun exposure during the day. Provide enough
hutches to allow a minimum of two weeks resting period after a calf is removed.
Locate hutches on a well drained area. Crushed rock or sand base provide a
solid base for bedding and lessen the possibility the hutch will freeze to the
ground in winter. After removing the calf, move the hutch to a clean site to
break disease cycles. Use enough bedding to keep calves clean and dry and to
insulate calves from the ground. To provide operator comfort, hutches may be
placed inside a well ventilated shed or structure, in effect providing a cold
housing environment in winter and shade in the summer, Fig 3.
Individual calf pens,
Fig 4, can be used inside a
cold housing building. Pens are typically 4'x7' and removable. They provide
isolation for each calf. Solid partitions between pens and beyond the front of
the pen prevent nose-to-nose contact. A hover or cover on the back half of the
pen gives the calf additional protection in especially drafty locations. Pens
use building space more efficiently than do calf hutches, although increasing
animal density increases ventilation requirements. Place pens on a crushed rock
base or concrete floor to provide a base for bedding. Individual pens require
the same type of management as calf hutches.
Use individual 2'x4'
stalls only in warm housing. This system requires the least space per calf, but
must be used in insulated, environmentally controlled buildings with mechanical
ventilation and supplemental heat.
Drafts, which occur in elevated stalls with
open floors for drainage, are detrimental to calf health. The incidence of calf
disorders increases in warm housing facilities after several years, due in part
to warm temperatures. Warm temperatures increase viability of disease organisms.
The facility must be adequately ventilated and sanitized on a routine basis.
Good ventilation, proper sanitation and careful observation of calves are
especially essential in warm housing systems to reduce disease.
Table 7. Dairy
ventilating rates. Size the system based on total building capacity.
Moving a newly weaned
calf from an individual pen to a small group environment is an abrupt change or
transition. The combination of stresses due to new social interactions with other
calves, competition for feed and water, and a new housing system can seriously
affect calf growth and performance.
Giving special
consideration to the calf's environment can make this transition less stressful
as the calf adjusts to group living and learns to compete. Monitor calves for
adequate dry feed and water intake and make sure calves are disease free before
moving them into a group pen.
Provide transition
housing for calves from weaning to 5 months of age. Maintain
small groups of 4-5 calves per group with a small range in size or
age (I month maximum). Provide well bedded pens that allow 25-30 ft2 of resting space per calf. Have fresh water available at
all times. Transition housing should provide an environment similar to calf
hutches only in a group setting. Depending on herd size and the ability to observe
an individual calf, the maximum group size would be 20
calves.
Portable shelters or
super hutches can provide transition housing for calves from cold housing. A super
calf hutch is designed for up to six calves, Fig 5. An
optional paved lot and addition of a fenced area can be used with the super
hutches, Fig 6. Keep the shelter well bedded and alternate the
hutch site between groups of calves. In a pasture system the super hutch can be
rotated on the pasture, Fig 7. Waterers can be centrally
located or moved with the hutch site.
For herds greater than 100 milking cows, a series of 10'x24' pens can be used in a «transition barn» for calves up to six months old, Fig 8. Capacity
for this arrangement is six animals if the feed alley is scraped and eight
animals if the entire pen is bedded.
Transition barns
commonly have a 3:12 single slope roof with no insulation. The barns
should open to the south or east to take advantage of the sunlight. The eave in
the back wall is open to aid in moisture control in the winter. During summer
remove fabric or other coverings on the back and endwalls for natural ventilation.
Extend both ends of the barn 4' beyond the pen fronts to
minimize wind effects at the corners of the barn during cold weather. Locate
waterers in the feed manger line to minimize splashed water in the bedded area.
To minimize excessive drafts in long barns,
attach plywood to gates and hang fabric from the underside of the roof down to
the gate between alternate pens. During cold weather, place straw bales along
the bottom edge of the gates to stop drafts. Remove bales during warm weather.
Calf barns combine
individual pens, Fig 4, and transition group pens for calves into one
building design, Fig 9. A full open sidewall with curtain provides cross
ventilation in summer and draft protection in the winter. The upper half of the
building can be a pivot door or curtain for draft protection in winter. The
lower part of the wall can have removable panels for better summer ventilation.
Air movement through the building should be sufficient to maintain inside
temperature only slightly above outside temperature in the winter and slightly
below outside temperature in summer.
Use solid partitions
between calves to prevent nose to nose contact. Wire fences on fronts and backs
of pens allow better air circulation during warm weather, but arrange pens to
keep calves from contacting each other. In winter, use solid pen backs to
provide draft protection. Hovers may be needed in winter. Choose or construct
pens that are easily dismantled for manure removal.
There are several
options for housing heifers after transition housing. Regardless of housing
type, group animals according to a management plan considering nutritional,
health and reproductive needs of each group. At a minimum, a logical break in
grouping is a breeding age group and a bred heifer group.
The primary functions
of heifer housing are to:
Ø Minimize
animal handling for treatment.
Ø Allow for
animal breeding.
Ø Allow for
animal observation.
Even though heifers
can tolerate more stress as they grow older, they still must be protected from
wet conditions, drafts, and poor environment. In open front housing, provide
group pens of sufficient depth to protect heifers from winter winds. Solid pen
partitions help reduce drafts.
Young heifers are
grouped in freestall housing with stalls sized according to age or size of
heifer, Table 4. Freestall housing requires considerably less
bedding than bedded pack housing. Frequent manure removal is required (once or
twice a week), unless floors are slotted. Frozen manure can be a problem in
cold barns, but is manageable.
There are several
different layouts that can be used in freestall housing. Each alternative is
suited to particular feeding and manure handling situations. Each alternative
has adequate feedbunk space, Table 6. Freestalls can be inside
with outside lots for exercise and feeding. The trend is having freestalls and
feeding included under the building roof or confined area. Outside exercise
lots may still be provided for use during periods of good weather.
Two-row freestall
barns are typically used for up to 100 heifers, Fig 10. Freestall length for each group in Table 4 is
sized to provide maximum comfort for the size of animal in the group. Heifers
are grouped in pens around the perimeter of the building.
Manure is either scraped automatically, the
alley is slotted or flushed, because it is not possible to move animals during
tractor scraping. When animals have access to outside runs, tractor scraping
can be accomplished. Build an 8' alley when a feed cart is
used. For drive-through feeding, a 16'-18' alley is required.
A two-row graduated
freestall barn changes the length of the freestall in the pen by placing the curb at an
angle to the side of the building. Stalls at one end of the building are shorter
than at the other end of the building. The alley floor is sloped toward the
freestall where a grated gutter is used to remove manure. The floor slope
provides a self-cleaning floor. Stalls are bedded with chopped bedding to allow
movement of the manure and bedding through the grate. Gravity gutter, flush
gutter or barn cleaner can be used to remove manure. Building temperatures must
remain above freezing most of the time to prevent frozen manure in gutters.
This type of building requires a controlled natural ventilation system.
A two-row gated
freestall barn can provide good housing, Fig 11.
Two rows of freestalls along one side of a single bunk, all under roof,
provides flexibility in feeding system design. Depending on the particular layout,
feeding may be accomplished with a feed cart, mechanical bunk or mobile scale
mixer. In three-row barns, there is limited bunk space; when feed is always
available, competition for feed can be managed.
Two-row gated freestalls with optional outside exercise
lots, can be used in good weather, Fig 12. Manure in the gated
freestall system is easily removed by a tractor-mounted scraper. Cows are
fenced in one alley while the other alley is cleaned. When the feed bunk is located
on the south or east side in a cold barn, the bunk side of the building may be
left open. In warm housing, 4"-8" wide slats are an alternative for
manure handling. Slats could be placed over gravity channels to separate manure
from animals.
Gated freestall barns
can be expanded for larger herds by using a common center feed alley. Stall
rows are located on both sides of the feed alley. Feeding can be accomplished
with drive-through feeding alleys sized for a feed wagon or feed cart.
Bedded pack housing is
commonly used in conjunction with an outside feeding and exercise area, Fig 13. However, there are advantages of roofing the entire area including the
scrape and feeding alley. Provide enough space for each group of animals in the
bedded resting area, Table
3. The bedded area is roofed and provides
a warm, draft-free resting surface. Bedded pack barns are often sized to allow
installation of a scrape alley and freestalls at a later date.
Macadam or
crushed rock surface can be used under the resting area pack. If concrete is
used, provide drainage by sloping to the scraped manure alley. Add bedding to
the upper end of the resting area pack as needed. Remove manure and bedding as
a solid 2-4 times a year. A substantial amount of bedding is
required to keep animals clean and dry.
Paved feeding alleys
are typically scraped 2-3
times per week. Extending the roof
over this area reduces runoff. To provide for a system with an outside lot, the
feeding alley is extended away from the building and is generally not roofed.
Runoff must be controlled to prevent surface water and groundwater
contamination.
Outside drive-by
feeding can be done or the feed platform can be roofed under the same building
when a scrape alley is used. The bunk can be roofed separately when an outside
lot is used. Bunk space may be limited in this type of housing so feed should
be available at all times to limit competition.
The counter-sloped
barn, a relatively low cost facility, is based on a sloped resting and feeding
floor separated by a tractor scraped alley, Fig 14. The
resting floor and feeding floor are sloped 8% (l"/ft)
toward the center scrape alley and are self-cleaning. Size the resting area of
the pens to allow for a self-cleaning resting area. Table 3.
Runoff from
uncovered alleys must be controlled to prevent stream and groundwater pollution.
The building can also be designed to be completely under roof to control water
entry. This system is not recommended for heifers younger than six months or
bred heifers during the last three months of pregnancy because of bedding and
the larger group sizes.
Optional outside lots
can sometimes be incorporated into building design when desired. Outside lots
can help reduce manure accumulation in the building, but must be cleaned and managed
properly. Outside lots may be of some benefit in reducing foot and leg problems
in dry cows. Pasture is sometimes used as part of the feed ration. Animal
density is low to allow the pasture to recover after grazing. Pasture can be
rotated to provide rest and recovery of vegetation. Pasture that is too heavily
grazed becomes a dirt lot over time and can cause problems when not managed
properly.
