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.
Calf housing (up to weaning)
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.
Hutches in Cold Housing
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.
Hutch management
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 Pen in Cold Housing
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.
Individual Stall in Warm Housing
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.
| |Ventilating rates |
|Animal |Cold |Mild |Hot |
| |Weather[8] |Weather |weather |
| |cfm/animal |
|Calves 0-2 months |15 |50 |100 |
|Heifers | | | |
|2-12 months |20 |60 |130 |
|12-24 months |30 |80 |180 |
|Cow 1,400 lb |50 |170 |470 |
|Room |Cfm |
|Milkroom |— |— |600 |
|Milking parlor, |— |100 |400 |
|cfm/stall | | | |
Transition housing (3-5 months)
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.
Calf Shelter or Super Hutch
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.
Transition Barn
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 Barn
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.
Heifer housing (6-24 months)
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:
> Minimize animal handling for treatment.
> Allow for animal breeding.
> 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.
Freestall Housing
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 barn
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.
Two-row graduated freestall barn
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.
Two-row gated freestall
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.
Drive-through gated freestall
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
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.
Counter-sloped barn
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
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.
Dirt exercise lots tend to have a high animal density and typically
have little or no vegetative cover. They become muddy in wet weather and
can cause environmental mastitis in heifers before they enter the milking
herd. Use dirt lots only when weather permits.
Concrete paved exercise lots can be incorporated into building designs
either as an exercise area or an integral part of the building design.
Runoff from lots must be controlled and handled as part of the manure
handling and storage system. Additional labor is required to scrape lots
and dispose of manure. Consider the cost of a runoff control system in the
total system cost. Also consider water quality issues in the overall design
of the housing option.
По мере того как подрастает ремонтный молодняк, изменяются его
потребности. Под этим подразумевается необходимые изменения в среде
обитания животного. Когда телки подрастают, они изолируются от других
животных для уменьшения риска заболевания. По мере того как телка растет,
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