For dairy calves, two (or more) heads are better than
one
Benefits of pair or group housing of
calves and practical solutions for hutches
Jennifer Van Os,
Assistant Professor and Extension Specialist in Animal Welfare
Rekia Salter,
Masters student in Dairy Science
Kim Reuscher, PhD
student in Dairy Science
Department of Animal and Dairy Sciences, University of
Wisconsin-Madison
When
it comes to raising dairy calves, two – or more – heads are better than one in
several ways. For the past decades, the majority of calves in the U.S. and
Canada are housed singly before weaning. In recent years, however, an
increasing number of producers have been successfully raising dairy calves in
pairs or groups.
The
consensus from the research is now that pairs and small groups, when managed
well, can provide clear benefits. Housing milk-fed calves with at least one
social partner can result in triple-wins for animal welfare, calf growth
performance, and consumer perception – all of which are important for the
vitality and sustainability of the dairy industry.
Benefits
for the calf.
Having companionship is important for calves since
dairy cattle are a social species. Calves learn to play well with others of
their kind, both literally and figuratively. It’s important to maintain
per-calf space allowance, meaning an increase in total space for pairs or
groups. This larger space allows calves to show a wider range of natural
behaviors, including playing. Having social contact early in life helps them
learn appropriate social interactions and also improves their other learning
abilities. Calves raised in social groups show flexibility and adaptability to
change, including a better willingness to try new feeds such as hay and TMR.
This translates into improved resilience to stress and less bellowing during
weaning. When regrouped after weaning, they start feeding sooner and don’t show
the same growth check that individually raised calves commonly do.
Benefits for growth performance. Across a dozen studies, calves raised in pairs or small groups have outperformed single calves in one or more ways. Performance advantages were especially apparent for calves fed higher milk or replacer allowances (such as 8 quarts/day or more at the peak).
- Solid feed intake: by 1/4 to 1 pound per day pre-weaning and 3/4 to 2.5 pounds per day post-weaning
- Body
weight at weaning: by 5 to 9 pounds
- Average
daily gain: by ¼ pound
Becoming
established on solid feeds before weaning is important for stimulating rumen
function, and better early-life growth translates to earlier onset of puberty
and higher milk production at maturity.
Benefits
for consumer acceptance. In a Minnesota
study, the researchers surveyed over 1300 adults attending the Minnesota State
Fair. They were shown photos of calves in single, pair, or small-group pens in
a barn. Nearly half of the participants disapproved of individual housing,
whereas only 14% of people disagreed with pair housing and only 7% disagreed
with group housing. In contrast, two thirds of participants agreed with pair
housing and three quarters agreed with group pens, whereas only a third thought
single housing was acceptable. Nearly all of these fair-goers consumed dairy
products. This is the first study showing that social housing may be important
for continued consumer acceptance of dairy production.
Managing calf health. Dairy
producers who have chosen to shift to social calf raising have found that
changing their management sometimes comes with bumps along the way.
Nonetheless, many of the principles for promoting good health outcomes are
similar whether managing individuals, pairs, or groups. Limiting the spread of
disease between different pairs or groups is still a best practice. The risk of
respiratory disease is reduced by feeding sufficient high-quality colostrum to
promote passive transfer of immunity, feeding sufficient milk or milk replacer
for a high plane of nutrition, and ensuring ventilation for good air quality.
Sufficient space, clean and dry bedding, good biosecurity and sanitation,
limiting age differences within groups, and all-in-all-out practices are also
important.
Minimizing cross sucking. One
of the concerns some producers have about pair or group housing is the
opportunity for calves to engage in unwanted behaviors like cross sucking.
Excessive cross sucking is thought to lead to frostbitten ears, navel
infections, or mastitis or udder damage. Although the little research that has
been done has not found a consistent relationship between cross sucking and
those negative outcomes, there are nonetheless ways to reduce this nuisance
behavior.
When calves begin a milk meal, their instinctive
suckling behavior is stimulated and continues for at least 20 minutes. Feeding
milk or replacer through a teat instead of an open bucket, especially using a
slow-flow nipple, can redirect their suckling instinct more appropriately, both
while the calf is drinking and afterward.
Last summer, Ms. Salter tested this concept for
pair-housed calves in hutches. Calves were bottle fed until they were 2 weeks
old, when they were switched to either open buckets or slow-flow teat buckets.
All calves were fed 4 quarts of pasteurized milk per meal twice daily.
Step-down weaning occurred over the course of 12 days by halving the milk
volume at each meal, then feeding only once daily. Calves were totally weaned
by 8 weeks of age. Twice a week, Salter recorded the calves’ behaviors during
and after the milk meal. She found that when calves were fed milk using
slow-flow teats, they spent more time drinking their milk and less time sucking
on the water buckets, hutches, fence, and – mostly importantly – on each other.
Regardless
of pre-weaning housing, cross sucking sometimes increases directly after
weaning. Calves who are better established on solid feed are less likely to
cross suck, so gradual, step-down weaning based on starter intake can help.
Pair or group housing options. Social
housing can be done in many ways, either in a calf barn or outdoors in hutches
or super hutches. Last year, we surveyed over 200 Wisconsin dairy producers and
custom calf raisers. Nearly 20% of farms allow their pre-weaned heifers full
social contact, either in pairs or larger groups. These producers use a variety
of housing, demonstrating that there are many options for successful pair or
group raising.
Often times people picture “group housing,” to mean
large group pens with automatic milk feeders. Indeed, about a third of
producers in our sample who group house use auto-feeders. The most common
method, however, was housing calves in pairs or groups in a barn and feeding
them manually, either with mob feeders or with individual bottles or buckets.
Interestingly, one in five producers using pairs or groups house their calves
outdoors, either with “super hutches” or by connecting individual hutches (Photo 1). For producers who currently
use outdoor hutches, connecting pairs of existing hutches allows them a way to
dip their toes into pair housing without a substantial investment in new
housing infrastructure or a major change to their management style.
Photo 1: Calves
can be raised successfully in pairs using various housing types, including
connected hutches.
Heat stress in hutches. Calves
housed in outdoor hutches are more exposed to environmental extremes compared
to those housed in barns. In the summer, calves may experience dehydration,
poor welfare, and show reduced appetite, feed intake, and growth. Some types of
plastic hutches can create a greenhouse effect, gaining heat from the sun and
warming up inside. To prevent this, shade is the best defense. Trees or shade
cloth blocking at least 80% of UV light have been shown to reduce the
temperature inside the hutch.
Hutches can also be ventilated to increase airflow and
heat exchange. Researchers in Washington found that on days when hutches were
raised with cinder blocks, calves had lower respiration rates. Although
elevating the hutch is a simple solution, some producers have expressed
concerns about calf safety. An alternative is to prop open the rear bedding
door, install adjustable windows (such as Calf-Tel calf hutch vent covers - SHOP NOW),
or use a combination of these methods. When Ms. Reuscher was an undergraduate
at Tarleton State University, she compared these methods on large heifer-grower
operations in Texas.
More recently, Reuscher tested 32 pairs of heifer
calves in Wisconsin. Each pair was housed in adjacent individual Calf-Tel
hutches with a shared fence. Once the calves were paired at around 1 week old,
we added ventilation to one of the hutches in each pair by propping open the
back bedding door and opening the 2 rear ventilation windows near the base of
the hutch.We looked at hutch use in 20 pairs of calves when they were 8 weeks
old, right after they were weaned. During the warmest times of day between 12
and 5 pm, we monitored their behavior using time-lapse footage every 5 seconds.
Overall, calves spent 68% of their time in the ventilated hutch (Photo 2), with 16 out of the 20 pairs
spending over half of their time in that hutch.
Photo 2:
Pair-housed calves sought out ventilated hutches, spending 68% of their time
there instead of in a non-ventilated hutch.
On other days during the study, we kept calves inside
the hutches for 1 hour of time using a wire fencing panel. They were kept
either in separate hutches or in the same hutch together, and we repeated this
for both the ventilated and non-ventilated hutch in each pair. Before and after
calves were placed inside the hutches, we measured signs of heat stress.
When calves were in the non-ventilated hutch with
airflow only through the front door and roof vents, their respiration rates
stayed relatively stable over the course of the hour. This indicated that these
hutches did not have a greenhouse effect. Calves did not accumulate heat and
get hotter over time relative to when they were outdoors – but they did not get
cooler either.
In contrast, when calves were in the ventilated hutch,
their respiration rates were reduced by 10 to 20 breaths/min over the course of
the hour. This demonstrated that hutch ventilation had a cooling effect,
helping the calves dissipate heat. These patterns were consistent whether there
was only 1 calf in the hutch a time, or both calves in the pair (Photo 3), and whether the calves were in
week 4, 6, or 9 of life.
Photo 3: Hutch
ventilation cooled the calves down, even when both calves were inside the same
hutch.
Our initial results are a promising indication that
hutch ventilation translates quickly into reduced respiration rates for calves
in hutches, even when they are pair housed. Furthermore, the calves seek out
hutches with ventilation. By voting with their feet, the calves indicated a
significant preference for the cooler environment.
Reuscher is now further analyzing the calves’ behavior along with rectal, skin, and eye temperatures. She also recently finished a winter study to investigate whether pairing in connected hutches may provide an additional benefit for calves, who can help keep each other warm. We will share this information once available. Our goal is to help more dairy producers join the list of success stories for social raising.
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