Page 297 - The Welfare of Cattle

274 the WeLfare of CattLe

Physiological responses

When animals experience fear-based interactions with people, their bodies respond with activa-
tion of biological pathways that are intended to help the individual survive during periods of stress.
At their core, these responses are centered on increasing energy availability throughout the body
and getting that energy to the tissues that will need it to overcome a stressor.
In cattle, the impact of positive human interaction can be profound. One example can be found
in meat science research. The dark cutting condition—defined by dark lean muscle color and ele-
vated postmortem pH—is an area of focus for many meat scientists. The condition does not occur
regularly throughout the year, but seems to occur in “rashes” during the times of year when major
shifts in environmental conditions occur. Since beef from dark cutting carcasses may be difficult
for researchers to procure on a consistent basis due to the relative rarity of its occurrence, some
researchers have worked to establish models to create the dark cutting condition in cattle so they
would have a means of producing dark cutting beef when it was needed for study.
In one study of methods to induce dark cutting beef, researchers used castrated male Holstein
calves in an attempt to induce dark cutting beef through social isolation stress (Apple et al., 2005).
The investigators exposed the calves to either 0, 2, 4, or 6 hours of restraint and isolation stress prior
to slaughter. The restraint and isolation stress involved taping all four legs of each animal together
and laying them alone on their side on a padded surface. The rationale behind this approach of
inducing stress was centered on the idea that cattle were gregarious by nature and would experience
considerable distress if they were not allowed to stay with a group of conspecifics during a stressful
event (being tied up and denied the ability to move). The experiment was replicated four times over
a 4 week period with two calves per social isolation and restraint stress treatment per week. The
6-hour social isolation and restraint stress treatment consistently produced dark cutting meat in the
carcasses of the calves with the exception of 1 week (two calves).
The only explanation that the authors of the study could produce to explain the difference dur-
ing 1 week provided support for the concept that positive human interaction can have a substantial
calming effect on cattle. During that week of the study, the ambient temperature declined sud-
denly and drastically. This sudden drop in temperature is typically associated with an increase in
the occurrence of dark cutting. This was puzzling at first for the authors. As they reviewed their
methods, they found a difference in how the calves were handled during the cold week compared to
other weeks—the students that were working on the project felt badly for the calves since they had
to be tied up and left alone in the cold, so they sat with the calves intermittently and petted them.
The authors concluded that human presence and gentle contact helped the calves to cope with the
psychological distress associated with the treatment and the environmental stress of the sudden
temperature change. This study suggested that human presence and gentle contact has the potential
to improve the ability of Holstein calves to cope with stressors.
Rushen et al. (1999) reported that the presence of either an aversive or gentle handler resulted in
an increase in heart rate in dairy cows during milking. Control cows that were milked without either
the presence of a handler that had used gentle methods to move them or a handler that used aversive
methods to handle them displayed no change in heart rate from the pre-milking baseline. However,
the presence of the aversive handler caused a greater increase (5.94 beats/minute) in heart rate than
the gentle handler (3.42 beats/minute).

Behavioral responses

Multiple studies have been conducted to improve understanding of the behavioral implications of
human interaction and indicators of both positive and negative stockmanship styles (Ellingsen et al.,
2014). In one study, researchers worked to determine if gentle interactions—being stroked gently for
3 minutes per day for the first 14 days of life—with stock people would impact the flight distance of