reduced when supplement allowance w

reduced when supplement allowance was increased. Ducker
et al. (1981) reported that the proportion of grazing ewes not
consuming block supplement was highest when supplement
consumption by the total flock was low, and the proportion
of non-feeders decreased as supplement consumption by the
total flock increased. Kendall et al. (1980) combined the
effects of trough space and supplement allowance by offering
grazing ewes different amounts of supplements with varying
trough space. When supplement allowance was high, trough
space had little effect on CV of supplement intake. When
supplement allowance was low, trough space had a large
effect on CV of supplement intake.
Bowman et al. (1999) examined supplement use by 2-
and 3-yr-old cows on Montana rangelands. They reported
that 2-yr-old cows consumed less supplement than 3-yr-old
cows when supplement was offered for ad libitum consumption.
Restriction of the supplement with a different feeder
design resulted in similar consumption levels between the
two age groups. This supports Wagnon’s (1966) finding that
increasing competition may reduce overconsumption by
some animals.
Herd Leaders
The concepts of leadership and dominance are often confused,
but they describe two distinct behaviors. Animal
groups are led by individuals that initiate an activity (grazing,
traveling, or resting) that is different from the activity of the
remainder of the group. If the remainder of the group does
not follow, the "leader" returns to the activity of the group
(Sato, 1982). Leaders are individual animals that consistently
initiate movements that cause others to follow.
Leaders seem to be animals that move purposely in a direction,
attracting the attention of others (Tyler, 1972; Greenwood
and Rittenhouse, 1997). Purposeful movement may
come from having more knowledge of where resources are
located (Greenwood and Rittenhouse, 1997). This may
explain why, in spring, adult ewes of bighorn sheep migrate
to alpine range before yearling ewes (Festa-Bianchet, 1988).
However, Tyler (1972) found that any member in a group of
wild ponies could be a leader, even an immature animal.
Most studies have found little correlation between leadership
and dominance. Popularity or sociability may determine
leadership. Syme (1981) found that leaders in a group of
sheep were the more sociable animals. Reinhardt and Reinhardt
(1981) reported that the leader in a group of cattle was
the most popular cow; that is, the cow that was the preferred
associate of many herd members. She was an average cow in
terms of age, reproduction, weight, and social rank, but her
movements were attentively observed by the other group
members. Sato (1982) observed a tendency for high-ranked
cows to be leaders and low-ranked cows to be followers. This