Group housing for dairy calf: a win-win option
Every month, as I browse through the most recent issue of the Journal of Dairy Science, I am always first attracted to article titles that begin with the words "Invited Review." These reviews summarize the available scientific information pertaining to a specific topic. It is not uncommon to see two or three hundred references used to write these papers. This article is based on one of those reviews, which talks about calf health and housing.
A comparison of two worlds
Raising calves in individual pens or hutches, especially during the milk feeding period, has been heavily promoted until recently. What was considered a standard practice in the dairy industry is evolving to better reflect our understanding of animal behavior and welfare. Standard industry practices could be open to consumer scrutiny in the future and being proactive is an excellent way to demonstrate our willingness to do the right thing. What we perceive as being 'normal', for example, separating the calf and the dam shortly after birth could be challenged by both science and consumer perception.
Several reasons were raised to justify raising calves in individual pens or hutches. Isolating calves from one another to reduce disease spread, avoiding cross-suckling, minimizing competition and facilitating the management of calves of various ages, particularly in small herds.
During the last two decades, as dairy herd size has increased, various systems evolved on the farm to optimize labour and workload. Interest in housing calves in groups grew as increasing herd size generated a steady flow of calves of similar age. This allowed more producers to house their calves in groups as opposed to individually.
Numerous studies have examined the behaviour of individually-housed animals within a herd and the social interactions among individuals. For example, when given the chance, a newborn calf will form social bonds within the first week of life, first with its dam but also with other members of the herd. During the following weeks, calves tend to form small groups, which then interact with older animals as well. Calves in a herd will tend to start nibbling grass and ruminating at about three weeks of age, and graze regularly with the herd at three to six months of age. It appears social interactions let calves learn various behaviours, such as feed selection and grazing skills. Bovines are social animals. Lack of social interaction in early life can negatively impact a calf. Several studies have demonstrated the link between social isolation with abnormal behaviour and developmental problems in various species.
Social contact and behaviour
The relationship between the social environment and behaviour in calves is well documented. For example, calves raised in a group are less fearful and more dominant when mixed in groups later in life compared with individually-raised calves. Even calves raised in pairs will be less fearful than calves reared individually. Full social contact with other calves early in life establishes a stronger bond and promotes better social skills when compared with calves raised individually or with minimal visual or physical contact with other calves. The same is true when compared with calves socialized at a later time, such as after weaning.
Although dairy producers strive to minimize exposing cows to drastic changes, it is difficult to eliminate them completely. Changes in diet, pen location, pen mates, housing or bedding systems, or even a new milking system or milking procedure, as well as personnel can all lead to stressed cows. Studies have shown calves raised individually will show more adverse reaction to environmental changes than calves raised in a group setting. The overall adaptation abilities of group-raised animals are better than their individually raised counterpart. They tend to show less reactivity to restraints, have fewer stress symptoms when placed in a new pen with unfamiliar animals, and are less reluctant to consume a new type of feed. Bottom line is rearing animals in groups early in life improves their ability to adapt to a changing environment in the barn.
Group housing is beneficial to calves but it is also beneficial to dairy producers since this system reduces labour and saves time. It is also associated with an increase in dry matter intake and, consequently, increased average daily gain in dairy calves raised in groups compared with individually reared ones. When calves are in contact with herd mates, they will be stimulated to sample solid feed at a younger age and eat more, especially before weaning. Similarly, when raised in a group, calves will consume more concentrate and the onset of rumination will take place at an earlier age. Further, animals will show reduced stress response to mixing and weaning.
Dairy producers quickly adopted automated feeding systems, especially those designed for calves in group housing, when they were first introduced on the market. One of the main concerns about these systems was the potential for cross-sucking. You can mitigate this problem with proper management. Feeding milk through a teat instead of a bucket helps substantially. The ability of the feeding system to provide milk on a frequent basis coupled with an enhanced milk feeding program minimizes the incidence of cross-sucking. Recent studies report when calves are slowly weaned by an automatic feeder, incidence of cross-sucking is minimal, especially when the animals are already consuming significant amounts of solid feed.
You can implement certain management strategies to lessen competition and aggression between animals. Ideally, providing one teat per calf reduces competition. Placing barriers between teats can help, too. For automated feeding systems, reducing the ratio of calf per station and positioning the feeding stalls to limit aggression should mitigate the problem. Offering fewer but larger portions can lower competition as well, particularly for older calves since they tend to naturally consume larger and fewer meals per day.
Maintaining a stable group can lessen aggressive behaviour among calves. When mixing weaned animals is necessary, regrouping no more than two previously stable groups will result in less aggression than other mixing options. Groups composed of similar sized calves will be less competitive and perform better.
The most common health problems in young calves are scours and respiratory illnesses, which are not consistently associated with group housing. In other words, calf health is not dependent on the housing system but rather on how it is managed. Milk feeding method, hygiene, ventilation, colostrum management, diet, health monitoring and a vaccination program all determine a rearing system's success.
Raising dairy calves in groups from an early age is a win-win option, both for the animal and dairy producer. The calf can benefit from an enhanced social interaction conducive to wellness. The producer benefits from better animal performance in a system that can save labour and time.
Reference - Invited review:
Effects of group housing of dairy calves on behavior, cognition, performance, and health. Journal of Dairy Science Vol. 99 No. 4, 2453-2467, 2016.
This article was originally published in the Milk Producer Magazine.
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