aggression during feeding. However, feed
intake was unchanged. In contrast, when
cows were fed limited amounts of feed,
dominant cows consumed 14% more feed
than submissive cows. This divergence
increased to 23% as competition increased
from one to four cows per feeding station.
Thus, under conditions of limited feed
availability, competition escalates and feed
intake of submissive cows suffers.
A major consideration when managing
dairy cattle is the proper amount of feeding
space allowed per animal to ensure that
feeding behaviour is not affected adversely.
When lactating dairy cows are fed at a feed
bunk or manger, the critical length of bunk
space per cow, below which excessive
competition occurs, varies with the group
size and amount and availability of feed.
However, manger divisions that protect the
head may allow submissive cows to eat
longer, even in competitive situations
(Bouissou, 1970). Several early reports
established that little change occurred in
feeding behaviour when bunk space was
reduced from 0.61 to 0.31 m per cow
(Albright, 1993). A reduction in bunk space
from 0.49 to 0.09 m per cow to increase
competition strengthened the correlation
between dry matter intake and the
dominance value of the individual cow.
Albright (1993) postulated that a gradual
reduction in bunk or manger space for an
established group of cows may be better
tolerated than adaptation of a new group to
limited manger space.
The early research on feeding space
and behaviour evaluated small groups of
cows (50–60 or fewer) at low to moderate
levels of milk production. Application of
these results to modern dairies requires
observations of larger groups of cows at
higher levels of milk production and feed
intake. The traditional rule of thumb of
0.61 linear metres of bunk space per cow is
the minimal amount of space required for
all cows to eat at one time. However, the
advent of TMR and proper feed bunk
management raises questions regarding the
adequacy of this relationship. Table 17.2
summarizes the relationship between feed
bunk space and feeding activity as sum-
marized from the scientific literature (Grant
and Albright, 1997).
Menzi and Chase (1994) conducted a
field study using two commercial dairy
herds in New York state to examine feeding
behaviour and bunk use for high-producing
herds. Both herds were producing in
excess of 10,600 kg of milk yearly, were
milked three times daily, used 6-row drive-
through free stall barns, and were fed a
TMR two (Herd 1) or three (Herd 2) times
daily, with 88–90 cows in each group. The
groups of cows observed for each farm had
the highest feed intake and milk produc-
tion per cow, and therefore should have
exerted the greatest feeding pressure on the
bunk. Cows in these groups averaged 40 kg
of milk day^1 with a dry matter intake of at
least 24 kg day^1. A video camera was
mounted above and slightly behind the
feeding area to provide the best view of
feeding activity. Each herd was videotaped
for a 24-h period during August when high
temperatures were 27°C and low tempera-
tures were near 16°C. Using the videotape,
a feed bunk usage score was developed
where 0 represented no animals at the feed
bunk and 10 indicated that the bunk space
was entirely occupied with no additional
room for animals to eat. The feeding
behaviour data from these two herds are
shown in Fig. 17.1.Feeding Behaviour 369Table 17.2.Bunk space and feeding behaviour of lactating dairy cowsa.
Bunk space Effect on dry matter intake
<0.20 m Reduced eating time and dry matter intake
0.20–0.51 m Increased competition with variable effect on dry matter intake
0.51–0.61 m No measurable effect on dry matter intake
aData summarized from Albright (1993), Friend and Polan (1974), Friend et al. (1977), Manson and Appleby
(1990) and Menzi and Chase (1994).