ingested during each bout were calculated. On total, the behaviour analyses were based on 2756 observations.
2.4. Data analysis Behaviour data, as expressed in percentages of time devoted to a single behaviour,
were homogenized for variance, using arcsine transformation, before analyses of vari- ance were carried out. The effects of level of Q and PEG supplementation, of heifer and
Ž .
of feeding cycle, on feed intake experiments 1 and 2 , and on feeding behaviour Ž
. Ž
. experiment 2 were evaluated by bifactorial Latin square analyses SAS, 1985 . In
addition, paired T-tests were used to verify if PEG supplementation neutralised the effects of Q on feed intake and behavioural characteristics.
3. Results
3.1. Effects of quebracho meal and PEG on food intake in heifers 3.1.1. Experiment 1
In the first phase of experiment 1, no changes in feed intake occurred when heifers were provided with Q at levels less than 500 grday, but higher levels of Q impaired
Ž .
intake Fig. 1 . A 33 decrease in feed intake from ca. 12 to 8 kg was noted when 1 kg of Q was included in the diet. Feed intake was restored to 12 kg when the daily supply
of Q was reduced to 500 g. When the feed intake data were sorted into three classes Ž
. according to levels of Q viz. 0, 0–500, 500, a significant P s 0.05 depression was
Ž .
noted for the 500 level Fig. 2 .
Ž .
Ž .
Ž Fig. 1. The effect of quebracho supplementation - - - on the daily feed intake FI, — of Holstein heifers kg,
. Ž
. fresh fed CMD ad lib experiment 1 .
Ž .
Ž .
Titles: X-axis: days on experiment. Left Y-axis: FI kgrday . Right Y-axis: quebracho in diet grday .
Ž . Fig. 2. The effect of quebracho supplementation, as classified in three levels, on the daily feed intake FI of
Ž .
Holstein heifers fed CMD ad lib experiment 1 . Ž
. Ž
. Titles: X-axis: level of quebracho grday . Y-axis: FI kg .
In the second phase of experiment 1, provision of 1 kg of Q lowered feed intake from Ž
. Ž . Ž
. 11.8 control to 9.6 kg Q
Fig. 3, P s 0.005 . None of the PEG levels completely succeeded in restoring feed intake. When heifers were given Q-PEG40, they consumed
10.3 kg of CMD, which did not differ statistically from the Q diet. When given Q-PEG80, feed intake was increased to 10.6 kg which still tended to be lower than the
Ž .
control Fig. 3; P s 0.08 . Intense salivation was noted in heifers at all levels of Q ingestion.
3.1.2. Experiment 2 Pre-experimental feed intake during 1 week prior to experiment 2 was similar
Ž between heifers, i.e., 12.1 0.15 kg. Overall, supplementation of Q decreased Table 1,
Ž .
Fig. 3. The effect of PEG level on the daily feed intake FI, kg of Holstein heifers fed CMD ad lib and Ž .
supplemented with 1 kg of quebracho Q . Ž
. Ž
. Titles: X-axis: PEG-Q amounts in diet grday . Y-axis: FI kg .
Table 1 Ž
. Ž
. Ž
. Ž
Average feed intake FI, kg , number of eating bouts NEB , time spent at eating ET, min , eating rate ER, .
Ž .
Ž .
Ž .
grmin , water intake WI, kg , watering rate WR, mlrmin , feed:water ratio FIrWI within 180 min after Ž
. Ž
. distribution of the ration, feed intake subsequent to 180 min observations FI
and daily FI kg in heifers
180
Ž . Ž
. Ž .
H fed a CMD without supplement C, control , or supplemented with 625 grday of quebracho Q , with 250 Ž
. grday of PEG, or with 625 grday of quebracho and 250 grday of PEG Q-PEG .
Ž .
Diet C
Q Q-PEG
PEG Main effects P s
Q PEG
Q=PEG H
Within 180 min
a b
a a
FI 10.50.9
6.40.6 9.80.9
9.90.9 0.007
0.09 0.06
0.31
b b
a b
NEB 15.01.9
24.31.8 13.31.9
12.61.7 0.007
0.01 0.02
0.26
a b
a a
ET 1309
1015 1309
1208 0.16
0.17 0.03
0.10
a b
a a
ER 84.46.3
63.34.0 78.46.3
81.86.0 0.02
0.23 0.20
0.81
ab b
a ab
WI 19.42.6
15.81.6 23.32.3
21.12.4 0.16
0.03 0.80
0.01 WR
5.61.3 3.40.8
5.51.2 4.11.1
0.68 0.77
0.18 0.01
FIrWI 0.520.10
0.400.06 0.420.10
0.470.09 0.59
0.76 0.23
0.39
a b
ab ab
Daily FI 12.70.6
11.00.4 12.50.7
12.00.5 0.23
0.33 0.14
0.50
b a
b b
FI 2.20.5
4.60.4 2.70.6
2.10.5 0.001
0.01 0.77
0.15
180
Within rows, means with a common superscript do not differ significantly. P - 0.05
P - 0.01.
. P s 0.007 feed intake during the 180 min subsequent to distribution of rations, while
Ž .
PEG tended to have a positive effect P s 0.09 . The Q = PEG interaction also tended Ž
. to be significant P s 0.06, respectively . Average overall feed intake by heifers fed the
Q diet, as measured within 180 min after CMD distribution, was 60 of that measured
Ž .
Fig. 4. Daily feed intake FI, kg in heifers during 180 min following feed distribution: heifers were fed CMD Ž .
Ž . with no supplement C , or supplemented with 625 grday of quebracho Q , with 250 grday of PEG, or with
Ž .
625 grday of quebracho and 250 grday of PEG Q-PEG . Arrows indicate first days of the four cycles in the Latin square.
Ž .
Titles: X-axis: days on experiment. Y-axis: FI kg .
Ž .
Fig. 5. The number of eating bouts for 180 min after food distribution NEB : heifers were fed CMD with no Ž .
Ž . supplement C , or supplemented with 625 grday of quebracho Q , with 250 grday of PEG, or with 625
Ž .
grday of quebracho and 250 grday of PEG Q-PEG . Arrows indicate first days of the four cycles in the Latin square.
Titles: X-axis: days on experiment. Y-axis: no. of eating bouts.
Ž .
in the controls Table 1, P s 0.006 . Intense salivation was noted in Q, and to lesser extent, in Q-PEG-fed heifers. The feed intake of heifers fed PEG or Q-PEG did not
Ž .
differ from that of the controls. A larger portion of the diet 41 vs. less than 22 was consumed after the 180-min observation period by heifers when fed Q, compared with
Ž .
other diets Table 1, P s 0.05 . The overall daily feed intake was still lower in heifers Ž
fed Q than in all the other groups. This reduction represented 10 compared with .
Ž .
P-PEG, P s 0.07 to 14 compared with C, P s 0.03 of the total daily intake. Ž
. When analysed on a day-by-day basis Fig. 4 , it appears that Q-fed heifers ingested
consistently less feed throughout the experiment than counterparts fed other diets. However, in each of the four feeding cycles, the difference in intake within 180 min
Fig. 6. The duration of eating bouts for 180 min following food distribution: heifers were fed CMD with no Ž .
Ž . supplement C , or supplemented with 625 grday of quebracho Q , with 250 grday of PEG, or with 625
Ž .
grday of quebracho and 250 grday of PEG Q-PEG . Ž
. Titles: X-axis: no. of eating bouts. Y-axis: duration of eating bouts min .
Ž .
Fig. 7. Eating rate ER, grmin at eating bouts for 180 min following food distribution: heifers were fed CMD Ž .
Ž . only C , or CMD supplemented with 625 grday of quebracho Q , with 250 grday of PEG, or with 625
Ž .
grday of quebracho and 250 grday of PEG Q-PEG . Ž
. Titles: X-axis: no. of eating bout. Y-axis: ER grmin .
after distribution between the Q group and the controls was highest on the first day and lowest on the last day of the cycle. Similarly, differences in total daily intake between Q
Ž .
Ž .
and C decreased from 4.2 0.05 kg P s 0.04 to 0.1 0.03 kg not significant from the first day to the last day of each cycle. This observation suggests that heifers adapted,
at least partly, to diets containing Q. No differences in feed intake were found at any date between Q-PEG and C, indicating that the negative effect of Q on the intake of
CMD was neutralised by PEG from the first day of each experimental period.
On average, the number of eating bouts for 180 min after distribution of the ration Ž
. Ž
. was increased by Q Table 1 and Fig. 5, P s 0.007 and decreased by PEG P s 0.01 ,
Ž .
with a significant P s 0.02 interaction between these effects. When supplemented with Ž
. Q, without PEG, heifers exhibited a higher P s 0.0007 number of eating bouts during
the 180 min observation period, compared with other dietary treatments, that did not
Ž . Ž .
Fig. 8. Feed intake FI per eating bout for 180 min after food distribution: heifers were fed CMD only C , or Ž .
CMD supplemented with 625 grday of quebracho Q , with 250 grday of PEG, or with 625 grday of Ž
. quebracho and 250 grday of PEG Q-PEG .
Ž .
Titles: X-axis: no. of eating bouts. Y-axis: FI per eating bout .
Table 2 Ž
. Ž
. Percentage of eating bouts that ended in standing ST or drinking DR during 180 min after distribution of
diets. C
Q Q-PEG
PEG Main effects
Q PEG
Q=PEG H
b a
ab b
ST 71.75.7
84.04.0 68.75.8
67.25.7 0.18
0.05 0.40
0.06
a b
ab a
DR 26.95.6
15.13.9 29.95.7
29.25.6 0.26
0.08 0.33
0.06 Within rows, means with a common superscript do not differ significantly:
‡
P - 0.10.
differ between them. In other words, PEG supplementation annihilated the effects of Q on the eating bout pattern after feed distribution.
No significant effect was found for Q and PEG on time spent at eating. However, Ž
. heifers spent 22 less time eating when fed Q than when fed C or Q-PEG P s 0.005 .
Ž .
Eating rate was decreased P s 0.02 by Q, but not by PEG. When fed Q, heifers Ž
. exhibited eating rate lower by 25, 23 and 19, compared with C P s 0.008 , PEG
Ž .
Ž .
P s 0.01 and Q-PEG P s 0.06 , respectively. The duration of eating bouts and, in Ž
. particular, of the first eating bout Fig. 6, P s 0.01 was shorter in heifers when fed the
Ž Q diet, compared with other diets. This, added to lower eating rate in heifers fed Q Fig.
. Ž
. 7 , resulted in lower feed intake during the main eating bout Fig. 8 , which could not be
bridged within 180 min. While the number of eating bouts did not differ between the Q-fed and control heifers
on the first day of each cycle on which diets were just switched, Q-fed heifers exhibited Ž
more eating bouts, starting from the second or third day of each feeding cycle Fig. 5, .
P s 0.04 . Ž
. The percentage of eating bouts that ended in standing Table 2 was higher when
Ž heifers were fed the Q diet than the C, PEG and Q-PEG diets 84 vs. approximately
. 70 . Respective differences were significant at P s 0.08, 003 and 0.02. In contrast,
Ž less eating bouts ended in watering in Q-fed heifers higher 15 vs. approximately
. 30 .
The water intake during 180 min after distribution of the diet was increased by PEG Ž
. Table 1, P s 0.03 . Heifers drunk less water when fed the Q diet than the PEG diet
Ž .
P s 0.007 , other treatments being intermediate. A strong heifer effect was found on Ž
. water intake
P s 0.006 . The ratio of food to water intake did not differ between Ž
. groups Table 1 .
4. Discussion
