Replacement Housing

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.

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 |