Types of Housing Systems for Nursing Calves
The primary objective for calf housing is to provide the calf with a clean, dry, and comfortable environment that is properly ventilated with easy access to feed and water. This can be accomplished by housing calves individually or in groups, inside or outside of a barn.
There is no “one” way to successfully house calves. Rather, calf housing varies from farm to farm depending on management and the available labor.
Calf health in any type of environment is complex and dependent on many factors such as stocking density, failure of passive transfer, hygiene and bedding management, feed rates and consistency, disease detection, ventilation, and vaccination.
The perceived gold standard for calf care has been the calf hutch – favored by smaller herds and large western dairies, and less costly than the construction of a new building to house calves. Each calf has its own microenvironment inside the hutch with outside access to its own milk and water. Hutches make it easier for caregivers to observe the sick, but subject caregivers to harsh climates.
Hutches
Hutches have an advantage over barns for housing nursing calves in that they provide a more flexible solution to ensuring adequate time and physical space to isolate newborns. Occupied hutches should face away from the prevailing winds and be spaced far enough apart that sick calves do not contaminate their healthy neighbor’s environment. Additionally, the area in which the hutches are kept should be large enough to move the hutch from one site to another during the 1- to 2-week cleaning period so that the plot on which the hutch rests can be cleaned and dried. A newborn calf may then be placed in a disinfected hutch on a clean and rested plot.
Sufficiently deep bedding, particularly straw is a must during the winter months to allow the calf to “nest” and trap a layer of warm air around itself, resulting in less heat loss. A clean calf jacket can be added for extra warmth. In the summer, a dry, clean bed of straw, sawdust, or shavings is fine.
Calf Barns
One of the major decisions to make when planning a new calf facility is whether to design for individual or group rearing of calves. This decision is mostly influenced by the type of milk diet the producer wishes to feed as well as how the feed will be delivered – by hand, automation, or mob feeders. Some herds have invested in equipment to pasteurize waste milk while others rely on milk replacer. Increasingly, those that use pasteurized waste milk typically build individual calf pen housing, while those who wish to utilize milk replacer invest in automated feeding systems and group housing.
A. Individual Pen Systems
An extension of the individual calf hutch is the individual calf pen within an enclosed facility. Properly designed calf facilities with individual pens can obtain the same results as hutches. Proponents of individual calf pens claim that there is a reduced risk for the spread of disease, less competition for feed so starter intake can be closely monitored, and navel sucking is prevented. Surprisingly, there is little scientific evidence to support a consistent relationship between individual housing and calf health when compared with small groups (e.g. Waltner-Toews et al., 1986; Perez et al., 1990; Johnson et al., 2011).
Individual calf housing ensures that each calf is observed at least once during each feeding. Individually housed calves displaying behavioral signs of illness may be more obvious to the caretaker than those housed in large groups where sick calves may go unnoticed. However, if calves are not being fed their nutritional needs, their appetite may not decrease simply because they are still hungry. It is common for pneumonic calves to continue feeding aggressively, masking the onset of disease. Also, it is certainly true that calves in individual pens are more easily caught and restrained for examination, treatment, and other procedures than calves kept in large, open areas.
There is a growing body of scientific evidence that individually reared calves suffer cognitive deficits compared to socially reared calves (Meagher et al., 2015; Gallard et al., 2013), creating a significant cause for concern amongst those concerned with the welfare of the milk-fed calf. This finding precludes us recommending individual pens without social contact after 14 days of age. However, we support and promote the concept of pair raising of calves starting at 14 days of age. This approach carries with it many of the social benefits of group rearing while achieving similar benefits to individual pen rearing in a similarly designed facility. In barns with individual pens, replace every other solid panel with a mesh panel, or remove the panel separating two pens completely.
For hutch management, in order to comply with welfare requirements and improve socialization, we recommend that at 14 days, two hutches be joined by one outside fence so that two calves are mixed together for the remainder of the rearing period.
B. Group Pen Systems
There has been renewed interest in group rearing systems for pre-weaned calves with improvements in computerized calf feeding equipment, and a significant move toward higher rates of milk feeding in these systems. Automatic feeding systems allocate a pre-programmed portion of a total daily allowance of milk or milk replacer to be fed to an individual calf when it enters the feeding station. Calves are fed with pre-set time lags between their meals, while having the potential behavioral benefit of unrewarded visits to the feeding station to simply nurse on a dry nipple. The computer records the duration, intensity and volume of each feeding, alerting the manager to calves with changes in their feeding behavior that may indicate illness or failure to adapt to the system. Weaning occurs automatically at a set age (and, if measured, at a goal weight and level of starter intake), by reducing the amount of milk or replacer allocated to calves over a predetermined period of time, typically one week.
Calves are social animals that need exercise. Keeping dairy calves in groups may provide a number of advantages to both dairy farmers and their calves. Successful adoption of group housing will mean avoiding problems such as disease transmission and competition for access to food resources. Group pens allow calves a larger area for activity and interaction with group-mates. In one study, calves on an automatic feeder in small groups of 5 to 7 calves spent more time lying, showed less oral behavior, performed less self-grooming, and had fewer hair balls in the rumen than calves entirely housed individually (Bokkers & Koene 2001).
On the other hand, group housing may lead to nursing calves developing negative behaviors such as cross-sucking and competitive and dominance behavior. Competition around the feeder has been found to be greater in larger (24) versus smaller groups (12) of calves. Calves in larger groups spend more time waiting for access to the feeder and less time occupying the feeder by themselves, make more attempts to access an occupied feeder, displace more calves from the feeder, and enter the feeder more often as soon as it is available (Jensen, 2004).
Group housing of nursing calves has been associated with increased risk of respiratory and gastrointestinal disease compared to individual calf housing (Svensson and Liberg, 2006) with groups of 6 or greater calves being associated with increased disease and death in nursing calves compared to individual and smaller group housing (Svensson et al., 2003; Svensson and Liberg, 2006; Losinger and Heinrichs, 1997). Some studies have found an advantage in health while others have shown no difference in disease and treatment rates for calves in automatic feeding systems, but group size in these studies was either small (de Passille et al., 2004) or not reported (Kung et al., 1997), and very different from the 25 to 35 calf groups being recommended by some manufacturers to off-set the cost of the automated feeding equipment. Based on clinical experience, the most successful herds have 20 calves per nipple.
Diseases related to abomasal emptying and milk replacer osmolality may be better prevented through the use of automatic calf milk feeders because calves consume more meals in smaller quantities at a restricted flow rate spread throughout the day, rather than two or three larger, more concentrated meals that may be consumed too quickly if milk or milk replacer is fed in buckets to calves in individual pens. Calves allowed free-choice intake will consume 1.6 to 3.2 gallons (6 to 12 liters) of milk replacer per day, even at just one week of age (Anderson, 2010). However, problems with the calibration of the mixing machines and powder clumping in the outlet can result in wide deviations from expected milk replacer concentrations, leading to less than desirable calf performance. Calves kept in larger groups (e.g. >24 calves) will spend less time at the feeder and ingest their meals more quickly (Jensen, 2004), which gives greater necessity to proper computer programming for feeding frequency in typical U.S. systems.
Overall, it is clear that group and individual housing systems can be a success or failure based on their management, and the choice between the two should fit with the producer’s philosophy on rearing and fit with their management expertise.