Page 351 - The Welfare of Cattle

328 the WeLfare of CattLe

impacts lying behavior. Cows given dry bedding materials spent approximately 4 hours more per
day lying than those with very wet bedding (Fregonesi et al., 2007). Reich et al. (2010) also found a
dose-dependent response with lying times gradually increasing across five levels of bedding mate-
rial dry matter content.
While the selection and maintenance of bedding materials are both very important consider-
ations, they are unable to compensate for improperly sized stalls (Popescu et al., 2013). The average
size of dairy cows has increased steadily over the last 30 years (Bouffard et al., 2017), often without
concomitant changes in stall designs. This has led to a situation where many farms have stalls that
are simply too small for their cows (Zurbrigg et al., 2005; Dippel et al., 2009; Westin et al., 2016;
Bouffard et al., 2017). Perching occurs when cows stand with two feet in the stall and two feet in
the alley. This behavior is often interpreted as an indication of a cow’s reluctance to lie in the stall.
Perching behavior has been observed more frequently on farms with stalls that fail to meet standard
stall size recommendations (Tucker et al., 2004; Lombard et al., 2010). A more recent study found
smaller stall dimensions were associated with increased risk of neck and leg injuries, as well as
lameness (Bouffard et al., 2017).
Other aspects of stall design affect stall usage as well. Like neck rails, brisket locators are bar-
riers designed to control the forward limit of the recumbent cow in free stalls. Brisket locators may
be constructed from a variety of materials including PVC, wood and concrete. If they protrude
too far from the stall surface the cow’s ability to normally rise will be impeded and disruptions in
normal lying behavior may occur. Tucker et al. (2006) found cows housed in free stalls preferred
to lie down, and lied down longer, in stalls that had had their brisket locators completely removed.
In a similar fashion, the neck rail functions to delineate the forward limit a cow can comfortably
stand within the stall. A large cross-sectional study found stall occupancy significantly increased
when the height of the neck rail was raised just 13 cm relative to the bedding surface (Fulwider and
Palmer, 2005). However, experimental research failed to detect any effect of neck rail height on
lying times (Tucker et al., 2005). This somewhat surprising null result might have been an artifact of
the rather limited range of neck rail heights manipulated in the study. The horizontal distance from
the neck rail to the stall’s rear curb does seem to have an effect on how the stall is used for standing
as stall usage increases with the effective length of the stall (Fregonesi et al., 2009). Bernardi et al.
(2009) found increasing the distance between the neck rail and the rear curb improved lameness
scores. Complete removal of the neck rail leads to substantially longer lying times, however it also
leads to dirtier stalls and increased the risk of mastitis (Tucker et al., 2005). This constant tension
between providing a comfortable environment for the cow and maintaining a high level of cleanli-
ness is commonly encountered in the cow comfort literature.

MaStItIS

Mastitis, or inflammation of the mammary gland, is the common name used to describe a broad
range of symptoms associated with intramammary infections. Mastitis is a painful condition and
one of the most common infectious diseases affecting dairy farms (Barkema et al., 2006). Between
lost milk production, increased mortality and treatment costs, the average cost of a case of clini-
cal mastitis is estimated to be $179 (Bar et al., 2008). Like most infectious diseases, mastitis is the
result of the interplay between host resistance, environmental conditions and pathogen virulence.
Over the past 100 years, improved understanding of the range of etiologic agents, programs to con-
trol contagious pathogens, and the use of antibiotics and teat sealants at dry-off have contributed to
more effective mastitis management protocols (Ruegg, 2017). The development of vaccines against
mastitis pathogens, and research into a potential genetic basis for resilience are likely to further
improve cow-side resistance (Rupp and Boichard, 2003; Ismail, 2017), but changes in housing and
management are currently much more feasible for the average farm.