affected foraging strategies. Behaviors evaluated were assists, total arm entrances before 1 and 2 barley feeders were discovered, and the total number of occasions that heifers
traveled to arm ends before finding one or two feeders with barley. Heifers often entered arms and consumed oats without traveling to arm ends. Thus, arm entrances were
indicators of the search for oats, and travel to arm ends indicated a search for barley.
Ž .
Average values from the last 2 days of initial training were evaluated. Groups n s 4 were used for pairing.
2.8.2. Followers For all three treatments, followers were treated identically during initial training and
the pretest. All followers received barley in the same fixed locations during the pretest, exposure, and test sessions. For followers, the only difference among treatments
occurred during the two exposure sessions when ‘‘leader’’ heifers that had previously Ž
. received different initial training i.e., fixed, variable, no-experience were allowed to
forage with the followers. The effect of leader initial training on the behavior of heifers assigned as followers
was analyzed as a randomized complete block design. Initial training regimes of leaders Ž
. Ž
. Ž
. were the treatments
n s 3 and heifer groups nine animals were blocks n s 4 .
Dependent variables analyzed were the total visits to barley feeders by followers during Ž
. Ž
. the two exposure with leader and four test sessions without leader and the total
Ž number of visits to barley feeders by followers during the four test sessions without
. Ž
. leaders . Observational data obtained from leaders including exposure sessions were
never included in analyses of follower data. Single degree of freedom orthogonal contrasts were used to determine if followers with experienced leaders differed from
followers with inexperienced leaders. We hypothesized that followers with experienced leaders would find barley feeders sooner and visit more barley feeders than those
exposed with inexperienced leaders.
A separate analysis using pooled data from all followers was used to evaluate if leaders facilitated the discovery of barley feeding sites by followers. A non-parametric
binomial test was used to determine if followers visited arm ends with barley more often than expected by chance. The percentage of time spent by leaders at feeders during
exposure sessions was calculated from observations to evaluate the probability that leaders were present at the time followers first found barley. Because followers had been
Ž .
trained to expect straw at arm ends and previous research Bailey and Sims, 1998 showed that cattle strongly avoided maze arms that contained straw, the timing in which
Ž .
followers visited barley feeders before, during or after a leader visit was used to evaluate if leaders facilitated the discovery of barley feeders by followers. Leaders from
all three treatments could provide new information since they were not trained to avoid arm ends.
3. Results and discussion
3.1. Leader behaÕior during initial training Leaders in the experienced-fixed, experienced-variable and no-experience treatments
averaged 0.6, 1.2 and 0.3 assists per session, respectively, during initial training. The
Ž .
experienced-variable treatment required more assists than the no-experience P s 0.03 Ž
. and experienced-fixed P s 0.08 treatments. Assistance for the experienced-fixed and
Ž .
no-experience treatments were similar P s 0.2 . Ninety percent of the assists occurred during the first 4 days of initial training. After 5 days of training, leaders with barley in
Ž .
fixed locations entered fewer P s 0.01 arms before finding barley than leaders with Ž
. barley in variable locations Fig. 2 . Leaders with barley in variable locations traveled to
the end of maze arms more frequently than the fixed location leaders before finding the Ž
. Ž
. first P s 0.08 and second P s 0.02 barley feeder.
Leaders in the two treatments appeared to use different search strategies. Leaders with barley in fixed locations usually entered an arm containing barley within their first
two or three choices. As they entered an arm they usually consumed the oats in the inner feeder and then traveled to the end for barley. Leaders with barley in variable locations
often consumed the oats in most of the inner feeders before traveling to arm ends to search for barley.
3.2. Tests for olfaction Ž
. During initial training, leaders in the variable treatment required more P - 0.05 arm
Ž .
entrances to locate barley than leaders in the fixed treatment Fig. 2 , which suggests
Fig. 2. Mean number of arm entrances and visits to arm ends by experienced-fixed and experienced-variable leaders before the first and second feeders with barley were discovered during the last 2 days of initial training
Ž .
days 6 and 7 . Entry-1 and Entry-2 refer to the total number of arm entrances before one or two barley feeders were found, respectively. End-1 and End-2 refer to the total number of arm ends visited before the first and
second barley feeders were found, respectively. Means within each entry or end comparison that do not share a Ž
. common letter differ P -0.05 .
that cattle did not rely on olfaction to locate food in the maze. If heifers had been using olfactory cues to locate barley, arm entrances required to find barley should have been
similar for the fixed and variable location leaders. Moreover, followers did not find barley during the pretest, before exposure with leaders. Similar to other research with
Ž .
cattle Bailey et al., 1989a,b; Laca, 1998 , heifers in this study apparently did not use olfactory cues to locate grain.
3.3. General social facilitation effects During the study, followers had the opportunity to visit and consume barley in 24
Ž total locations two locations per pair of followers, three pairs per group, and four
. groups . Followers visited and consumed grain at least once in 18 of the 24 locations
Ž .
75 . Because followers had been trained to expect straw at arm ends during initial training, finding 75 of the barley locations suggests that social facilitation may have
occurred because heifers would be expected to avoid maze arms that were paired with Ž
. straw Bailey and Sims, 1998 . Followers also visited arms with barley more often than
Ž .
expected by chance P - 0.01 . Followers visited arm ends 205 times during the
Ž .
exposure and test sessions, and 97 of the visits 47 were to arms with barley. Only 25 of heifer visits would be to arms containing barley by chance since two of the eight
arm ends contained barley.
Fig. 3. Total number of barley feeders located during exposure and test sessions by followers exposed with leaders in the experienced-fixed, experienced-variable and no-experience treatments. The first bar represents
the total number of barley feeders found out of a possible 24. The remaining three bars show the number of Ž
. barley feeders visited simultaneously by both leader and a follower with leader , number of barley feeders
Ž .
Ž .
found first by a leader leader first , and the number of barley feeders first found by a follower follower first .
Ž . A leader was present during 11 of the 18 occasions when a follower s first visited a
Ž .
feeder with barley Fig. 3 . This is significant because leaders were only present during Ž
. two of the seven trials that followers were exposed to barley 29 of the total time , and
leaders spent less than 40 of their time in the maze within arms with barley. The probability of a leader being present at the arm end when a follower discovered a feeder
with barley is less than 0.05 if one considers that leaders spent about 40 of their time in arms with barley at the end feeders. During test sessions, followers returned to feeders
Ž .
with barley a second time on 8 of the 11 occasions 83 after they first visited it when a leader was present.
Followers usually did not find a feeder with barley if the leader did not visit it first. Four of the six feeders with barley, not found by followers during the study, were in the
no-experience treatment where leaders did not find the barley. We noted that followers appeared to redirect their route to the barley feeder when they noticed the leader
foraging at a feeder. Our data support the hypothesis that cattle with knowledge of food locations can pass that information to its peers. It is our supposition that a conspecific
with its head down in a feeder was the visual cue that heifers used to predict that food other than straw was available in that location. It is possible, but unlikely, that other
factors such as the sounds made during eating were used as cues to locate feeding sites.
Ž .
Behavior did not change when the weather changed e.g., windy versus calm days . Ž
. Winds were predominantly from one direction southwest , which would have muffled
eating noises made downwind.
Fig. 4. Total number of visits to barley feeders by followers during exposure and test sessions in the Ž
experienced-fixed, experienced-variable and no-experience treatments for the four groups experimental
. blocks and the mean value of each treatment.
3.4. Effect of leader training on social learning Initial training of leaders did not affect the total visits to barley feeders by followers
Ž .
Ž .
P s 0.4 or the visits to barley during the test sessions P s 0.6 . The mean number Ž
. visits to barley was similar P 0.8 among groups of heifers. However, the behavior of
individual followers in the no-experience treatment of group 2 differed from those in the Ž
. Ž
. other three groups Fig. 4 . One of the followers heifer 5094 found both barley feeders
Ž .
on the second day of the first test session day 10 . At that point, heifer 5094 acted as a leader and the no-experience leader and the other follower accompanied her to the
barley feeders on the second exposure the next day. Based on initial observations, heifer 5094 was the least docile of the heifers used in the study. This heifer often traveled
down maze arms several times during a session and appeared to be attempting to get out of the maze. After finding the barley, she consistently returned to those maze arms.
4. Conclusions
