As replacement heifers grow, their needs change. This includes a change in needed physical environment. When a heifer is young, it is physically separated from other animals to minimize the risk of disease. As it grows, it is grouped with other animals to increase resistance to disease and prepare the animal for the breeding herd. Eventually the animal enters the breeding herd and finally the milking herd.
Each stage of production requires housing to meet the physical needs of the animal.
Management factors. Affecting design
House replacement animals in separate facilities away from the milking herd to foster a healthy environment for each group. Well-designed and properly-managed replacement animal housing allows the ability to adopt the best management practices currently recommended. Plan space, equipment, environment, rations and care to meet the needs of each group. Manage replacements in groups according to their specific requirements. Facility design should allow for easy implementation of the management plan for each group. When planning replacement animal housing, provide:
> Adequate resting and exercise space.
> Covered, dry and draft-free resting area.
> Good quality fresh air.
> Adequate space for feed and water.
> Space to group animals by size or age.
> Clean lots to maintain sanitary conditions.
> Isolation area for sick animals.
> Observation area for animals.
> Treatment facilities.
> Space for handling and restraint of animals.
Poorly planned or improperly managed animal housing increases the risk of disease or injury. High humidities are especially detrimental to animal health. Pneumonia, scours and other diseases can permanently damage vital body organs and reduce milk producing potential of an animal. Calves and heifers raised in a poor environment may never reach their full genetic potential for milk production.
For healthy, high producing replacement animals, provide high quality housing and a management plan that addresses animals' needs. Good management, understanding what to do and then doing it on schedule, is important to the success of any housing system. Sanitation, stall maintenance, bedding, ventilation control, feeding, herd health, treatment and close observation are all important management practices. Young animals may need training and/or time to get accustomed to using freestalls. Daily or routine chores such as feeding, stall maintenance or manure removal should be made as convenient as possible to make sure they are accomplished in a timely manner.
Herd size and makeup
Herd size can mean either the number of cows actually milking or mature cows both dry and milking. In this handbook, the herd size is the number of mature cows.
Typical herd makeup, assuming uniform calving year-round, is given in