The number of replacement animals to be housed depends on the number of milking cows and bred heifers. As herd size increases, so does number of replacements. Increasing herd size without expanding facilities for replacements results in crowding which can increase injury, disease transmission, and lower growth rates.
Table 1. Typical management categories of a herd.
This table is only a management guideline. These are categories and not group size
Herd size = total cows75100250400Calves and heifers
0-2 months, 150 lb
3-5 months, 250 lb
6-8 months, 400 lb
9-12 months, 600 lb
13-15 months, 800 lb
16-24 months, 1,000 lb75
6
9
9
14
9
29100
8
12
12
18
12
38250
20
30
30
45
30
95400
32
48
48
72
48
152Dry cows
Transition (first 4-14 days)
Next 40 days
(Divide in 2 groups)
Close-up
(2-3 weeks prepartum)13
0-4
8-9
2-517
1-5
11-12
3-643
4-9
28-30
8-1568
5-16
45-48
16-24Maternity (individual pens)3-54-610-1616-24Fresh cows
(from 0-7 days postpartum)1-31-43-104-12Two-years-old (305 days)18-2426-3065-75104-120Three years and older (305 days) b
High producers
(120 days or less)
Medium producers
Low producers44
15-18
12-15
12-1558
20-24
16-20
16-20145
50-60
40-50
40-50232
80-96
60-72
60-72Sick cows0-40-50-130-20Management groups
Separating replacement animals into groups according to age, size or special management needs allows each group to be treated according to its needs. Plan building space and layout for these groups of animals using Tables 2 and 3. More than one group can be housed in the same building, but allow for managing each group separately. In larger herds, separate facilities may be provided for each group. Some of the benefits of managing animals in groups are:
- Healthier animals by minimizing the risk of transmitting disease to younger animals.
- Good feed efficiency by reducing competition for feed.
- Calving at proper weight and size at 24 months.
- Feed handling ease, and proper diets according to age.
- Manure handling ease.
- Animal observation and handling ease for breeding, treatment and grouping.
- Proper ventilation and environment.
- Proper resting space or freestall size.
Space requirements for a particular operation depend on the housing system chosen and how replacements move from the resting area to feed and to water and back again. Herd size and makeup are guides to estimating the space needed for resting, but alley size, water space and bunk space must also be considered to accommodate the animals and provide an animal friendly environment.
Provide separate areas for resting and feeding. Feeding in resting areas increases manure accumulation and more bedding is required to keep animals clean and dry.
Resting space
Adequate resting space for management groups is a key factor in efficient growth. Required space for different housing alternatives including bedded resting areas, self-cleaning resting areas (solid, sloped floors) and freestalls are shown in Tables 3 and 4.
Feeding and watering space
Provide adequate feeding space, so young stock do not have to compete for feed. Optimum feeding space varies with type of feed, feeding schedule and animal size, Fig 1 and Tables 5 and 6.
Water is essential at all times. Provide at least one watering space per 20 animals. Dairy heifers need 1-1,5 gal of water daily per 100 lb body weight. Select waterers that are easy to clean; protect them from freezing. Locate waterers on elevated curbs and in a location that allows easy manure removal around them. Adjust waterer height to allow small animal access.
Handling and treatment facilities
Animal treatment areas are a necessary part of the replacement housing system. Vaccinations, artificial insemination, pregnancy checking, deworming, dehorning and examinations are done easily and safely for animals and workers when animals can be separated and restrained easily. Equipment that eases labor and saves time in handling animals are:
- Scales.
- Self-locking feed stanchions.
- Gating/fencing.
- Squeeze chute/breeding chute.
Prep room
Locate a work room near calf housing for feed storage, a refrigerator/freezer, hot water heater, cleaning sink, health records and supplies. This area can be used to prepare milk replacer and clean feeding equipment.
Feed and bedding storage
Store bedding and feed in the building or nearby. Reduce daily hauling and feeding time by storing a one to two weeks supply. Storage space depends on animal density, feeding frequency and feed availability.
Table 2. Calf and transition housing.
Housing typePen size02 months (individual pens)Calf hutch (plus 4'x6' outdoor run)
Bedded pen
Tie stall (warm housing only)4'x8'
4'x7'
2'x4'
3-5 months (groups up to 6 head)Super calf hutch
Bedded pen25-30 ft2/hd
25-30 ft2/hdTable 3. Replacement heifer resting area space requirements.
Age, monthsWeight, lbSelf-cleaning resting area,ft2Bedded resting area, ft2Slotted floor, ft2Paved outside lot, ft20-2
3-5
6-8
9-12
13-15
16-24
Dry cow100-190
190-350
350-500
500-650
650-800
800-1,200
> 1,300Do not use
Do not use
10
12
15
18
20d32 (4'x8' hutch)
28(4'x7' pen)
28
25
28
32
40
50Do not use
Do not use
12
13
17
25
35Do not use
Do not use
35
40
45
50
55
Table 4. Heifer freestall dimensions.
Stall width measured o. c. of 2" pipe stall dividers.
Stall length measured from alley side of curb to front of stall.
Age, monthsWeight, lbFreestall sizeNeck railWidth, inLength, inHeight above stall bed, inDistance from back curb, in6-8
9-12
13-15
16-24
Dry cow350-500
500-650
650-800
800-1,200
> 1,30030
33
37
42
4560
64
72
78
8428
30
34
37
4046
49
57
62
66Table 5. Suggested dimensions for post and rail feeding fences.
Age, monthsWeight, lbThroat height, inNeck rail height, in6-8
9-12
13-15
16-24
Cows360-490
490-650
650-780
780-1,200
1,200-1,50014
16
17
19
2128
30
34
41
48Table 6. Feed space requirements.
TypeAge, monthsMature cow3-45-89-1213-1516-24in/animalSelf feeder
Hay or silage
Mixed ration or grain
Once-a-day feeding
Hay, silage, or ration
4
12
12
4
12
18
5
15
22
6
18
26
6
18
26
6
18
26-30Cold housing
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:
- Less expensive to build.
- Less expensive to ventilate and heat.
- Better disease control.
- During cold weather, disadvantages of a cold housing are:
- Freezing can make manure handling difficult.
- Waterers must be protected from freezing.
- Frostbite of calves ears may be a problem.
- Increased feed required to maintain body heat.
Warm housing
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.
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 fr
