group and animals with a prior history of ill-
ness following ingestion of novel feeds. The
effect of flavour enhancers on feed-related
neophobia is unclear; certainly no feed or
flavour has been discovered that is instantly
acceptable to all ruminants, except possibly
mother’s milk (Launchbaugh, 1995).
Heat Stress and Feeding Behaviour
In addition to feeding management and
strategy, the environment can affect cow
comfort and feeding behaviour. Environ-
mental factors include temperature,
humidity, air movement and solar radiation.
Temperature is one of the primary factors
affecting the physiological requirements and
meal patterns of the dairy cow. Thermal
stress has decreased feed intake by 3–4 kg
day^1 in mid-lactation dairy cows (Grant
and Albright, 1995). Heat stress may slow
the rate of increase in dry matter intake post-
partum and exaggerate the pre-partum
decline in dry matter intake in dairy cows
(Grant and Albright, 1995).
Shaded cows in loose housing had
higher feed intake than cows without
shading (Fig. 17.7). Shaded and non-
shaded cows had greater eating activity at
night during conditions of heat stress.
Shading feed bunks located in outside lots
during heat stress conditions increased
feeding activity of periparturient cows by
63% versus unshaded feed bunk areas
during daylight hours (Grant and Albright,
1995).Conclusions
Feeding is usually the predominant
behaviour in ruminants; rumination can
take precedence only when it has been
restricted abnormally. Dairy cattle consume
feed efficiently whether at a feed bunk or
grazing. However, the grouping strategy,
feeding system design and apparatus, and
attributes of the feed itself may all impact
the cow’s ability to express aggressive
eating behaviour. Key components in deter-
mining feeding behaviour are the social
hierarchy, competition for feed, water,
space and feed availability within a group
of cattle. In fact, feed accessibility may be
the most important factor affecting an380 R.J. Grant and J.L. Albright
Fig. 17.7.Use of shading to reduce heat stress results in greater feed intake by lactating dairy cattle.