Page 347 - The Welfare of Cattle

324 the WeLfare of CattLe

tests (see Fraser and Matthews, 1997) that allow cows to choose aspects of the environment that
are important to them. Research focused on health has primarily been led by the veterinary profes-
sion (e.g., LeBlanc et al., 2006; Cook and Nordlund, 2009; Barkema et al., 2015) and has played an
especially important role in understanding common maladies such as lameness (von Keyserlingk
et al., 2009) and mastitis (Barkema et al., 2006).
This chapter will provide a brief overview of the impacts both extensive and intensive dairy
systems have on cow welfare. Within the dairy industry and many veterinary and animal science
departments, this type of research is often collectively referred to as “cow comfort” research.
Unfortunately, this term is vaguely defined so we have elected to simply focus on commonly
studied behavioral and health outcomes associated with different systems or specific features
of these systems. Where possible we highlight limitations of this work and suggest areas where
further research is needed. Given that we are located in North America, much of this chapter
will focus on the U.S. and Canadian dairy industries, but we will draw on examples from other
parts of the world when appropriate. Lastly, we will focus on the effect housing has on lactating
dairy cattle.

BrIeF OVerVIeW OF COMMON DaIrY hOUSING SYSteMS

tie Stalls

Most cows housed in North America spend the majority of time indoors in one of several differ-
ent housing systems. In tie stalls or stanchion barns, cows are tethered in a stall by a piece of rope or
chain. Stalls consist of a lying area that is specific to each cow. Although cows have limited ability
to move freely and socialize with other animals, tie stalls allow for greater individualized attention
than loose housing systems described later. Tie stalls are unique in that cows are typically milked
directly in their stalls and have their own individual feed and water stations located at the front of
their stall. The frequency and duration of tethering, as well as the opportunities afforded when not
tethered, vary considerably. Some farms will keep cows tethered for only a few hours a day and then
allow them pasture access when weather conditions permit, whereas others may tether cows almost
continuously year-round (Popescu et al., 2013).
Although tie stall housing affords greater individual attention than other housing systems it
also faces unique welfare challenges because it entails severe restrictions on the cow’s ability to
move. Cows tethered for extended periods of time exhibit increased cortisol levels and stereotypical
behavior (i.e., tongue rolling) persisting at least 4 months (Redbo, 1992; Redbo, 1993). After being
released from prolonged tethering cows also display increased locomotor activity, which some
authors see as a likely indication of frustration brought on by immobility (Veissier et al., 2008).
Tethering also greatly restricts the cow’s ability to engage in many normal social behaviors (e.g.,
grooming) that cows likely find rewarding (Krohn, 1994).
In the U.S., 39% of farms report using tie stalls or stanchions as their primary form of housing
(USDA, 2016). In Canada, approximately 75% of the milk supply comes from cows housed in tie
stall housing (Barkema et al., 2015). Tie stalls are much more commonly found in older dairy farms
with relatively small herd sizes; thus, they are becoming much less numerous as the dairy industry
continues to consolidate into fewer and larger farms (Robbins, et al., 2016).

Free Stalls

More than 40% of all U.S. dairy farms now use free stalls as their main form of housing (USDA,
2016). The growing number of large dairy farms increasingly prefers these systems because unlike
most tie stalls, they utilize separate milking parlors that allow for more efficient management of