Nutrition of draught oxen in semi-arid west Africa ...
Nutrition of draught oxen in semi-arid west Africa
3. Effect of body condition prior to work and weight losses during
work on food intake and work output
A. Fall’, R. A. Pearson’ and S. Fernandez-Rivera2
‘Centrefor Tropical Veterinary Medicine, Universify of Edinbtqh, Easter Bllsk, Roslin, Midlothian EH25 9RG
~Il~fernafional
Livrstock Rcsearch lnsfitute, International Crop Rescarch Institutcfor the Semi-Arid Tropics, Snhelinn
Centre, BP 12404, Niamey, Niger
Abstract
Eightee~z oxcn were allottcd to thuce treatment groq~s according to their body condition: poor, medium and good.
Work ollfput, speed, liue zuejghf nnci body cona!ifiolt wcre mrasured duriny 7 wceks when animais workrd 4 days/
zueek, 4 k/day, pull@ Ioads quivalent to 12.5 kgf/IOO kg live Weigkf. Tke animais 7wc givcn millet stoveu ad
libitum d”ring kours they did nof zuork plus IOg/kg M of a concentrate mix. Work did not irzfluence intake of
millet sfover. However, food intake improved as zuork progressed and animais in bad condition atc more millet
stover than animais in good body condition. Work performance was nffected by live -wei@t but net body condition.
Live-weight losses did not have a detrimental effecf on work performance. Power olltput improved dur@ the COLI~S~
of the experiment while animais were losing zueighf Anirnals in a11 treatment grolcps lost body weighf during the 7
weeks qf work but weight losses were more pronounced in oxen in good than ii? poor body condition. At the end of
fhe working period, animais zuere put on natzlral pasturcs withozrt supplementation. II took 4 weeksfor animais in
poor and medium body condition and G weeks for animais in good body condition to reach their pre-zuork livr
weight.
Keywords: body condition, draught animais, food intake, live weight, millet stover, work.
Introduction
than 4 weeks). Although the cropping season is short
Draught oxen in good condition and of suitable live
in semi-arid areas, many oxen are hired out or
weight are required to ensure timeliness in soi1
loaned to other farmers and used for transport.
preparation and in planting, crucial for successful
Hence those oxen that are available may be used
cropping in semi-arid areas of west Africa. This is
over extended periods.
because work output is a function of body size and
working animais preferably use long-chain fatty
Supplementary food is often recommended as a
acids from fat reserves to fuel muscular activity
means of producing draught oxen in good condition
during sustained exercise (Preston and Leng, 1987;
and live weight to optimize power available.
Pethick, 1993). Unfortunately, draught oxen often
However,
food supplementation is expensive.
lose weight during the dry season (Wilson, 1987).
Furthermore, investigations of the effect of dry
Therefore they have minimum live weight and body
season supplementation on draught oxen have
reserves at the start of the cultivation period when
generally failed to show any significant benefit of
farm power demand is highest. This is also a time
committing scarce food resources to work output
when food resources are scarce and do not match the
and consequently to better trop production (Dick0
nutrient
requirements
of draught oxen for
and Sangaré, 1984; Astatke et al., 1986; Khibe and
maintenance, let alone work. While body condition
Bartholomew, 1993). Feeding strategies for draught
and weight losses during work may not constrain
oxen cari be better planned if the minimum working
performance when animals are only used for short
weight for cultivation is known and if the losses in
periods (3 weeks), they take on greater significance
weight and body condition that animais cari tolerate
where animals are used for longer periods (more
before work output is affected are known. Hence in
227
228
Fall, Pearson and Fernbdez-Rivera
this study the relationship between body weight,
thermometer. Live weight was measured for 3 days
body condition, weight loss during work and work
consecutively at the beginning of each week.
output of draught oxen were investigated.
Body condition was assessed each week as defined
by Nicholson and Butterworth (1986). Each day,
individual food allowances and refusals were
Material and methods
weighed and a food sample taken, dried and ground
for laboratory analysis (Fall et nl., 1997%).
This experiment was conducted from July to
September 1994 at the International Crop Research
At the end of the 7 wecks of work, 10 animais were
Institute for the Semi-Arid Tropics (ICRISAT)
monitored for 2 months to investigate the rate of
Sahelian Centre in Niger. Eighteen oxen, aged 4 to 7
weight gain after work. The animals grazed rainy
years, with an average live weight of 326 kg, were
season natural pastures from 08.30 to 17.00 h without
used. They were given chopped millet stover ad
supplementation. They were kept in stables after
libitum, supplemented daily with 10 g dry matter
grazing and had access to water nd libitrrm. M was
(DM) per kg Mo.:’ of a concentrate mix made up (g/
measured for a 2-monthperiod every 2nd day in the
kg) of wheat bran (500), groundnut cake (350), rock
morning beforr grazing.
phosphate (50), crushed bone (50) and common sait
(50). Animals at rest were allowed to eat when other
ox teams were working.
During the course of the experiment two oxen, one in
team 3 (‘poor’ IBC) and one in team 6 (‘medium’
IBC), were impaired by joint disorders. They were
Treatments consisted of three levels of body
conseyuently allowed to rest from the 5th week of
condition before work (IBC). The oxen were given
the experiment. Sound oxen in these pairs were
enough food during the 3 months before the
teamed up SO that they could continue work for the
experiment in order to reach contrasting body
rest of the experiment. Therefore, different sets of
condition scores as defined by Nicholson and
data were used to analyse parameters of interest in
Butterworth (1986) on a scale from 1 (emaciated) to 9
this study. The data set used to analyse daily intake
(obese). Three pairs of oxen were assigned to each of
of millet stover and daily weight changes included
the three treatment groups with average body
a11 weeks and a11 oxen except ox 17 and 25. Teams 3
condition scores of 2.33, 3.67 and 5.67 for groups 1,2
and 6 were excluded from the analysis of speed,
and 3, respectively. Average M of teams in groups 1,
power and work output.
2 and 3 were 615,650 and 692 kg, respectively.
Statistical models used to analyse food intake,
The experiment lasted 7 weeks. Teams worked for 4
weight change, body condition, gpeed, power and
days each week. Work consisted of pulling a loaded
work output using Statistical Analysis Systems
sledge around a flat circuit. Each day, the teams
Institute (1985) are given below:
worked for 4 h to complete 10 laps of the circuit.
Work stopped when the set distance or the set time
(1) intake of millet stnver (7 ,DM per day per kg M
was complete or when oxen were unwilling to
and g DM per day per kg M’ .75)
continue or when it was judged that the oxen were
too tired to continue working. During the
Yiik, = ~ t C, + T,,,i + Ak + W, + C X A, + C X W,,
preparation phase an ergometer (Lawrence and
+ W X T,i,jl + Cijkl
Pearson, 1985) was used to measure work
performed, distance travelled and elapsed working
(2) change in live weight (g/day) and body condition
time for different known loads. A regression analysis
(points per week)
of force on sledge load was performed and used to
determine the load required for each team so that the
Y,;, = !J + Ci + T(,,j + W[ + C X WI, + W X T(i,jf + f’,lI
draught force exerted was equivalent to 12.5 kgf per
100 kg M. The following equation was used to
(3) speed (m/s) and power ( W and W/lOO kg M)
determine work loads: load (kg) = 0.201 X force (N) -
7.44.
Yjlkrli = /A + C, + T,;,, + W, + R,,, + C X Wlk + C X Ri,,,
+ w x T(ilik + eljkrrl
Animals were allowed to stop for 3 to 4 min after
each lap. Respiration rate and rectal temperature
where: Y = one observation of daily food intake,
were then recorded. Respiration rate was assessed by
daily weight change, weekly body condition score,
counting the number of flank movements for 30 s.
force, distance, speed, power or work; v = mean; Ci =
Rectal temperature was measured with a clinical
ith IBC score, i = 1,2 and 3 (1 = ‘poor’, 2 = ‘medium’,
Nutrition of draught cattle - 3
229
3 = ‘good’ IBC); T,,,j = jth oxen team nested within
Differences
(P < 0.01) in daily weight gain due to IBC
the ith IBC group, j = 1,2 and 3; Ak = kth activity, k =
were observed. Al1 oxen lost weight during the
0: rest, k = 1: work; W, = Ith experimental week, 1 = 1,
experiment but weight losses were highest in oxen in
2. .7; C X A,, = interaction between the ith IBC and
‘good’ IBC. Daily weight losses were 456 (se. 103.3),
the kth activity; C X Wil = interaction between the ith
308 (s.e. 103.3) and 719 (se 89.5) g/day for oxen in
IBC and lth week; W X T,,,j, = interaction between the
‘poor’,
‘medium’ and ‘good’ IBC, respectively.
ith week and the jth team in the ith IBC group; R,,, =
Weight losses averaged 21.9 kg for oxen in the ‘poor’
mth lap of the circuit travelled; C X Ri,,, = interaction
IBC group, 14.8 kg for oxen in the ‘medium’ IBC
between the ith initial body condition and the nzth
group and 34.5 kg for oxen in the ‘good’ IBC group
lap travelled; e = random error.
over 7 weeks. These weight losses were equivalent to
proportionately 0.074,0.047 and 0.099 of the initial M
The effect of IBC on daily intake, weight change,
for oxen in ‘poor’, ‘medium’ and ‘good’ IBC,
speed, power and work was tested using team
respectively.
within condition (T,w) as the error term. The
interaction between week and team within condition
Weight losses estimated from polynomial regressions
(W X T,,,,,) served as the error term to test the effects
are illustrated in Table 1. The pattern of live-weight
of week and the interaction between week and other
changes was the same irrespective of IBC. Daily
factors
included in
the model. Orthogonal
weight losses were highest during the 1st week of the
polynomial regressions were fitted for variables such
experiment and decreased from week 1 to week 4.
as week, lap, and their interaction with IBC to
There was a steady increase in weight losses from
investigate the trend in food intake, weight change,
week 5 to week 7. The regression of daily weight
speed, power and work over time.
losses on intake of millet stover showed no
association between these two measurements.
Results
Body condition scores of a11 oxen declined over time.
Linear effect of IBC (P < 0.05) and the linear and
The regression of body condition on time showed
quadratic effect of week (P < 0.05) on daily intake of
that the better the IBC the more severe was its
millet stover (g/day per kg M; g/day per kg MD,jg)
deterioration Body condition score declined at a rate
were seen (Table 1). The poorer the IBC the higher
of 0.006, 0.107 and 0.235 points per week, for oxen in
was the intake of millet stover. Intake of millet stover
‘poor’, ‘medium’ and ‘good’ IBC, respectively.
increased steadily over time and reached a plateau
by the 4th week. Food intakes on working and
In the 10 oxen monitored on good quality natural
non-working days were similar.
pastures after work, rapid weight gains were
Table 1 Daiiy infde (g/kg M and g/kg Mr1.is) of millet stover and daiJy Jive-weighf Josses ozw 7 meeks by oxen in ‘poor’, ‘mrdim and
‘good’ IBC on working and non-zuorking days
Daily weight losses (g/day)
estimated by
Daily food
Daily food intake
polynomial regression
intake g/kg M
g/ kg M[‘,75
IBC
Sources of variation
Mean
s.e.
Mean
se.
Significance ‘Poor’
‘Medium’ ‘Good’
Initial body condition
Linea?
‘Poor’
18.1
0.26
75.1
1dx3
‘Medium’
17.2
0.26
72.9
1.07
‘Good’
15.2
0.22
64.8
0.93
Activity
Rest
17.2
0.20
72.2
0.86
Work
16.6
0.19
69.7
0.79
Week
Linear”**
1
13.8
0.22
58.1
0.94
Quad.+**
206
409
1193
2
15.4
0.24
64.8
1.00
4 7 7
306
650
3
16.3
0.23
68.4
0.95
421
211
349
4
17.4
0.23
72.9
0.95
272
185
478
5
77.0
0.22
71.2
0.93
263
288
628
6
17.7
0.22
73.6
0.94
625
583
788
7
77.2
0.24
71.6
1.03
1592
1129
847
--
230
Fall, Pearson and Femandez-Rivera
observed as illustrated by the following regression
equations of M (kg) on time (60 days [D] after work):
M = 257 (s.e. 12) + 0.825 (s.c. 0.054) X D for oxen in
‘poor’ IBC (at the start of the experiment), M = 302
(s.e. 12) + 0.967 (s.e. 0.041) X D for oxen in ‘medium’
Power
IBC (at the start of the experiment), M = 303 (se. 11)
Sp”d
I’ower
w per
+ 0.870 (s.e. 0.037) X
Source of variation
D for oxen in ‘good’ IBC (at the
(m/s)
W)
100 kg M)
start of the experiment).
Initial body condition
‘Poor’
(1~91
637
117
The overall rate of change of M was similar
‘Mcdium’
W8h
637
107
irrespective of the IBC score. However oxen in ‘poor’
‘Good’
0.96
780
118
and ‘medium’ IBC had higher M gains (3,2Og/day
S.C.
0~005
1
0.6
per kg M) than oxen in ‘good’ IBC (2.87 g/day per kg
Lap
M). Oxen in ‘poor’ and ‘medium’ IBC were able to
1
0.95
706
317
reach their initial live weight 4 weeks, on average,
2
0~97
722
120
after work stopped. It took 6 weeks alter the
3
047
724
120
cessation of work for oxen in ‘good’ IBC to reach
4
0.95
706
117
5
0.92
690
115
their pre-work M.
6
0.92
685
114
7
03Y
666
111
IBC did not affect speed of work of teams. Power (W)
8
oa?
651
109
developed by teams in ‘poor’ and ‘medium’ IBC was
9
0437
651
108
similar but significantly lower than power output
10
@87
646
107
(W) of oxen in ‘good’ IBC (P < 0.01). However, when
se.
om
6
1
Week
power was expressed relative to live weight (W per
1
0.78
,590
Y5
100 kg M), the effect of IBC was no longer significant.
2
044
631
103
Three oxen teams with approximately similar M and
3
0+3
653
107
in different body condition (team 1: ‘poor’ IBC,
4
0%
725
120
719 kg, team 2: ‘medium’ IBC, 721 kg; team 3: ‘good’
5
1 al
744
124
IBC, 739 kg) developed similar power output (team
6
0%
713
120
1: 775 W; team 2: 697 W; team 3: 741 W).
7
0.99
739
126
se.
0.07
5
1
Differences in speed and power output due to week
of work were significant (P < 0.01, Table 2). Speed
Early in lactation increases in DM intake were seen
and power output increased steadily over weeks for
in cows with a Iow body condition as compared with
a11 teams irrespective of their IBC. Even though oxen
those in a better body condition (Jones and
lost body weight throughout the experiment, there
Garnsworthy, 1989). As suggested by Faverdin rf nl.
was a significant weekly increase of 0.035 m/s and
(1995), undernutrition induces an increase in food
25.1 W in speed and power, respectively.
intake when food unavailability is no longer a
limiting factor.
Lap number had a significant effect (P < 0.01) on
speed and power output. Two contrasting phases
The steady increase in food intake and power output
were observed in the pattern of power output each
over 7 weeks observed in this study suggests that
day. During the first three laps of work (1st h) there
oxen underwent an adaptation to work during the
was an increase of 0.07 m/s and 9 W in speed and
first days of work. They became more adapted as
power each lap. In the second phase starting from
work went on and they were therefore able to
the fourth lap a steady decline in speed and work
increase their intake. Bartholomew ct nl. (1994) also
output of 0.014 m/s and 10.3 W were observed for
attributed increases in speed of working teams over
each lap completed.
time to adaptation to work. Therefore, working
during the dry season would bave the advantage
Discussion
that oxen are fit when cultivation starts and do not
As in previous studies (Fall ci al., 1997) work did not
have to undergo this adaptation period in the
affect intake of millet stover. These results are
cropping season.
consistent with most other studies that indicated no
differences i n i n t a k e i n w o r k i n g animais a s
During the preparation phase of the experiment oxen
compared with animais at-rest (reviewed by Pearson
were given food to reach the targeted body condition
and Dijkman, 1994). Poor body condition bcfore
and live wcight. This was however difficult t o
work was conducive to higher intake of millet stover
achieve because live-weight changes were associated
than good body condition before work over 7 weeks.
with changes in body condition. At the start of the
Nutrition of draught cattle - 3
231
experiment heavier animals tended to have better
820 N (Khibe and Bartholomew, 1993). They could
body condition than lighter animals. In order to
however pull heavily loaded carts without undue
minimize the confounding effect of M and IBC on the
stress.
rate of work (W) in different treatment groups,
power output was expressed relative to M (W per
It was expected that weight losses would adversely
100 kg M). The use of power relative to M to
affect work output. In this experiment power output
investigate the effect of IBC on work performance
improved over weeks while oxen were undergoing
was based on the assumption that oxen in ‘good’ IBC
weight losses. The same trends in live-weight change
had a higher fat content per kg M than oxen in ‘poor’
and power output were reported by Bartholomew et
or ‘medium’ IBC.
nl. (1993). Therefore the weight losses oxen cari
tolerate before work output is affected are difficult to
Power output is a function of speed and draught
estimate. Continuous and severe weight losses cari
force. The latter was set in this experiment to be
compromise the health of the animal, or even its life.
proportional to M. Therefore any advantage of oxen
However in this experiment, oxen were able to
in good condition over those in poor condition
regain live weight at a rapid rate when they had
would have been expressed as a higher average
access to good quality pasture during the rainy
walking speed. As compared with oxen in poor
season. It took them 4 to 6 weeks to reach their
condition, oxen in good condition would perform
pre-work live weight.
work at a higher rate or for a longer period of time
because they would bave more body reserves to
At the start of the cropping season, various body
draw on to fuel muscle activity. However walking
conditions are found in oxen because of differences
speed was not significantly affected by body
in food resources, management practices and the
condition in this experiment. Furthermore, the effect
disease situation in farming systems in the semi-arid
of IBC on power output was no longer significant
zone. Observations from this study suggest that a
when power output was expressed in relation to M.
body condition score of between 2 and 3 as defined
The similarity of power output relative to M for a11
by Nicholson and Butterworth (1986) would be a low
oxen suggested that animals with same body mass,
critical score below which work may irreversibly
irrespective of fat content, generated the same power
damage the oxen’s health. The ideal body condition
output This suggests that power output is more
score would range between 4 and 6. These animais
dependent on body mass than body condition. Oxen
are not too fat nor too lean and cari perform well if
in good condition did not out-perform oxen with
they are in good health. Oxen with a body condition
equal M but in poor body condition. These results
score of over 6 may be too fat to move comfortably
are consistent with those reported by Bartholomew et
and are more susceptible to heat stress than leaner
nl. (1994). These authors evaluated the relative
oxen. Moreover, the feeding level required to reach a
importance of body weight and body condition on
body condition score over 6 is unlikely to be
work performance by applying the same load of
profitable as far as feeding for work performance is
367 N to groups of oxen weighing 310 and 360 kg
concerned.
and in good and poor condition. Light oxen in good
condition could not sustain the work level applied.
Oxen should be supplemented during the cropping
They concluded that live weight rather than body
season when work is performed for more than 6
condition is the single most important determinant
weeks. If the working period is short, weight losses
of work output. Therefore, it seems that farmers
could be tolerated as animais will regain their live
should be encouraged to Select large-framed animais
weight rapidly. Supplementary feeding is however
for draught purposes. This may be constrained by
worthwhile for animals scheduled to be sold for
the fact that more Young animals are being used for
meat after work, even for short working periods, SO
draught purposes with a rapid on-farm turn-over
that work does not adversely affect their market
rate of these animals, apparently driven by an
value. In
semi-arid
west
Africa
food
attractive meat market. There is therefore a genuine
supplementation under these circumstances may be
need to investigate feeding and management
based on whole cotton seed, groundnut, sesame or
practices that Will optimize power and meat output
cotton cakes if available. These foods are rich in
in these farming systems.
protein and energy and provide substrates
(long-chain fatty acids, glycogenic compounds) that
Good IBC may allow work for longer periods of time
cari be directly used for work.
in the cropping season. In the present study, oxen in
‘poor’ IBC sustained average draught forces of
Acknowledgements
682 N. These animals might not be able to perform
The
authors
thank
the
Overseas
Development
ploughing or ridging for extended periods because
Administration (ODA) of the United Kingdom and the
these two activities require draught forces of about
International Livestock Research Institute for funding this
232
Fall, Pearson and Fernhdez-Rivera
study and E. A. Hunter for statistical advice during
Jones, G. P. and Garnsworthy, P. C. 1989. The effects of
prepnration of the manuscript,
dietary energy content on the response of dairy cows to
body condition at calving. A~~imnl Pmdurtim 49: 183-191.
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Editions, Paris
(Recriwd 29 /nmrnry 1996-Accr@cd 13 Sqhwzhcr 1996)
3. Effect of body condition prior to work and weight losses during
work on food intake and work output
A. Fall’, R. A. Pearson’ and S. Fernandez-Rivera2
‘Centrefor Tropical Veterinary Medicine, Universify of Edinbtqh, Easter Bllsk, Roslin, Midlothian EH25 9RG
~Il~fernafional
Livrstock Rcsearch lnsfitute, International Crop Rescarch Institutcfor the Semi-Arid Tropics, Snhelinn
Centre, BP 12404, Niamey, Niger
Abstract
Eightee~z oxcn were allottcd to thuce treatment groq~s according to their body condition: poor, medium and good.
Work ollfput, speed, liue zuejghf nnci body cona!ifiolt wcre mrasured duriny 7 wceks when animais workrd 4 days/
zueek, 4 k/day, pull@ Ioads quivalent to 12.5 kgf/IOO kg live Weigkf. Tke animais 7wc givcn millet stoveu ad
libitum d”ring kours they did nof zuork plus IOg/kg M of a concentrate mix. Work did not irzfluence intake of
millet sfover. However, food intake improved as zuork progressed and animais in bad condition atc more millet
stover than animais in good body condition. Work performance was nffected by live -wei@t but net body condition.
Live-weight losses did not have a detrimental effecf on work performance. Power olltput improved dur@ the COLI~S~
of the experiment while animais were losing zueighf Anirnals in a11 treatment grolcps lost body weighf during the 7
weeks qf work but weight losses were more pronounced in oxen in good than ii? poor body condition. At the end of
fhe working period, animais zuere put on natzlral pasturcs withozrt supplementation. II took 4 weeksfor animais in
poor and medium body condition and G weeks for animais in good body condition to reach their pre-zuork livr
weight.
Keywords: body condition, draught animais, food intake, live weight, millet stover, work.
Introduction
than 4 weeks). Although the cropping season is short
Draught oxen in good condition and of suitable live
in semi-arid areas, many oxen are hired out or
weight are required to ensure timeliness in soi1
loaned to other farmers and used for transport.
preparation and in planting, crucial for successful
Hence those oxen that are available may be used
cropping in semi-arid areas of west Africa. This is
over extended periods.
because work output is a function of body size and
working animais preferably use long-chain fatty
Supplementary food is often recommended as a
acids from fat reserves to fuel muscular activity
means of producing draught oxen in good condition
during sustained exercise (Preston and Leng, 1987;
and live weight to optimize power available.
Pethick, 1993). Unfortunately, draught oxen often
However,
food supplementation is expensive.
lose weight during the dry season (Wilson, 1987).
Furthermore, investigations of the effect of dry
Therefore they have minimum live weight and body
season supplementation on draught oxen have
reserves at the start of the cultivation period when
generally failed to show any significant benefit of
farm power demand is highest. This is also a time
committing scarce food resources to work output
when food resources are scarce and do not match the
and consequently to better trop production (Dick0
nutrient
requirements
of draught oxen for
and Sangaré, 1984; Astatke et al., 1986; Khibe and
maintenance, let alone work. While body condition
Bartholomew, 1993). Feeding strategies for draught
and weight losses during work may not constrain
oxen cari be better planned if the minimum working
performance when animals are only used for short
weight for cultivation is known and if the losses in
periods (3 weeks), they take on greater significance
weight and body condition that animais cari tolerate
where animals are used for longer periods (more
before work output is affected are known. Hence in
227
228
Fall, Pearson and Fernbdez-Rivera
this study the relationship between body weight,
thermometer. Live weight was measured for 3 days
body condition, weight loss during work and work
consecutively at the beginning of each week.
output of draught oxen were investigated.
Body condition was assessed each week as defined
by Nicholson and Butterworth (1986). Each day,
individual food allowances and refusals were
Material and methods
weighed and a food sample taken, dried and ground
for laboratory analysis (Fall et nl., 1997%).
This experiment was conducted from July to
September 1994 at the International Crop Research
At the end of the 7 wecks of work, 10 animais were
Institute for the Semi-Arid Tropics (ICRISAT)
monitored for 2 months to investigate the rate of
Sahelian Centre in Niger. Eighteen oxen, aged 4 to 7
weight gain after work. The animals grazed rainy
years, with an average live weight of 326 kg, were
season natural pastures from 08.30 to 17.00 h without
used. They were given chopped millet stover ad
supplementation. They were kept in stables after
libitum, supplemented daily with 10 g dry matter
grazing and had access to water nd libitrrm. M was
(DM) per kg Mo.:’ of a concentrate mix made up (g/
measured for a 2-monthperiod every 2nd day in the
kg) of wheat bran (500), groundnut cake (350), rock
morning beforr grazing.
phosphate (50), crushed bone (50) and common sait
(50). Animals at rest were allowed to eat when other
ox teams were working.
During the course of the experiment two oxen, one in
team 3 (‘poor’ IBC) and one in team 6 (‘medium’
IBC), were impaired by joint disorders. They were
Treatments consisted of three levels of body
conseyuently allowed to rest from the 5th week of
condition before work (IBC). The oxen were given
the experiment. Sound oxen in these pairs were
enough food during the 3 months before the
teamed up SO that they could continue work for the
experiment in order to reach contrasting body
rest of the experiment. Therefore, different sets of
condition scores as defined by Nicholson and
data were used to analyse parameters of interest in
Butterworth (1986) on a scale from 1 (emaciated) to 9
this study. The data set used to analyse daily intake
(obese). Three pairs of oxen were assigned to each of
of millet stover and daily weight changes included
the three treatment groups with average body
a11 weeks and a11 oxen except ox 17 and 25. Teams 3
condition scores of 2.33, 3.67 and 5.67 for groups 1,2
and 6 were excluded from the analysis of speed,
and 3, respectively. Average M of teams in groups 1,
power and work output.
2 and 3 were 615,650 and 692 kg, respectively.
Statistical models used to analyse food intake,
The experiment lasted 7 weeks. Teams worked for 4
weight change, body condition, gpeed, power and
days each week. Work consisted of pulling a loaded
work output using Statistical Analysis Systems
sledge around a flat circuit. Each day, the teams
Institute (1985) are given below:
worked for 4 h to complete 10 laps of the circuit.
Work stopped when the set distance or the set time
(1) intake of millet stnver (7 ,DM per day per kg M
was complete or when oxen were unwilling to
and g DM per day per kg M’ .75)
continue or when it was judged that the oxen were
too tired to continue working. During the
Yiik, = ~ t C, + T,,,i + Ak + W, + C X A, + C X W,,
preparation phase an ergometer (Lawrence and
+ W X T,i,jl + Cijkl
Pearson, 1985) was used to measure work
performed, distance travelled and elapsed working
(2) change in live weight (g/day) and body condition
time for different known loads. A regression analysis
(points per week)
of force on sledge load was performed and used to
determine the load required for each team so that the
Y,;, = !J + Ci + T(,,j + W[ + C X WI, + W X T(i,jf + f’,lI
draught force exerted was equivalent to 12.5 kgf per
100 kg M. The following equation was used to
(3) speed (m/s) and power ( W and W/lOO kg M)
determine work loads: load (kg) = 0.201 X force (N) -
7.44.
Yjlkrli = /A + C, + T,;,, + W, + R,,, + C X Wlk + C X Ri,,,
+ w x T(ilik + eljkrrl
Animals were allowed to stop for 3 to 4 min after
each lap. Respiration rate and rectal temperature
where: Y = one observation of daily food intake,
were then recorded. Respiration rate was assessed by
daily weight change, weekly body condition score,
counting the number of flank movements for 30 s.
force, distance, speed, power or work; v = mean; Ci =
Rectal temperature was measured with a clinical
ith IBC score, i = 1,2 and 3 (1 = ‘poor’, 2 = ‘medium’,
Nutrition of draught cattle - 3
229
3 = ‘good’ IBC); T,,,j = jth oxen team nested within
Differences
(P < 0.01) in daily weight gain due to IBC
the ith IBC group, j = 1,2 and 3; Ak = kth activity, k =
were observed. Al1 oxen lost weight during the
0: rest, k = 1: work; W, = Ith experimental week, 1 = 1,
experiment but weight losses were highest in oxen in
2. .7; C X A,, = interaction between the ith IBC and
‘good’ IBC. Daily weight losses were 456 (se. 103.3),
the kth activity; C X Wil = interaction between the ith
308 (s.e. 103.3) and 719 (se 89.5) g/day for oxen in
IBC and lth week; W X T,,,j, = interaction between the
‘poor’,
‘medium’ and ‘good’ IBC, respectively.
ith week and the jth team in the ith IBC group; R,,, =
Weight losses averaged 21.9 kg for oxen in the ‘poor’
mth lap of the circuit travelled; C X Ri,,, = interaction
IBC group, 14.8 kg for oxen in the ‘medium’ IBC
between the ith initial body condition and the nzth
group and 34.5 kg for oxen in the ‘good’ IBC group
lap travelled; e = random error.
over 7 weeks. These weight losses were equivalent to
proportionately 0.074,0.047 and 0.099 of the initial M
The effect of IBC on daily intake, weight change,
for oxen in ‘poor’, ‘medium’ and ‘good’ IBC,
speed, power and work was tested using team
respectively.
within condition (T,w) as the error term. The
interaction between week and team within condition
Weight losses estimated from polynomial regressions
(W X T,,,,,) served as the error term to test the effects
are illustrated in Table 1. The pattern of live-weight
of week and the interaction between week and other
changes was the same irrespective of IBC. Daily
factors
included in
the model. Orthogonal
weight losses were highest during the 1st week of the
polynomial regressions were fitted for variables such
experiment and decreased from week 1 to week 4.
as week, lap, and their interaction with IBC to
There was a steady increase in weight losses from
investigate the trend in food intake, weight change,
week 5 to week 7. The regression of daily weight
speed, power and work over time.
losses on intake of millet stover showed no
association between these two measurements.
Results
Body condition scores of a11 oxen declined over time.
Linear effect of IBC (P < 0.05) and the linear and
The regression of body condition on time showed
quadratic effect of week (P < 0.05) on daily intake of
that the better the IBC the more severe was its
millet stover (g/day per kg M; g/day per kg MD,jg)
deterioration Body condition score declined at a rate
were seen (Table 1). The poorer the IBC the higher
of 0.006, 0.107 and 0.235 points per week, for oxen in
was the intake of millet stover. Intake of millet stover
‘poor’, ‘medium’ and ‘good’ IBC, respectively.
increased steadily over time and reached a plateau
by the 4th week. Food intakes on working and
In the 10 oxen monitored on good quality natural
non-working days were similar.
pastures after work, rapid weight gains were
Table 1 Daiiy infde (g/kg M and g/kg Mr1.is) of millet stover and daiJy Jive-weighf Josses ozw 7 meeks by oxen in ‘poor’, ‘mrdim and
‘good’ IBC on working and non-zuorking days
Daily weight losses (g/day)
estimated by
Daily food
Daily food intake
polynomial regression
intake g/kg M
g/ kg M[‘,75
IBC
Sources of variation
Mean
s.e.
Mean
se.
Significance ‘Poor’
‘Medium’ ‘Good’
Initial body condition
Linea?
‘Poor’
18.1
0.26
75.1
1dx3
‘Medium’
17.2
0.26
72.9
1.07
‘Good’
15.2
0.22
64.8
0.93
Activity
Rest
17.2
0.20
72.2
0.86
Work
16.6
0.19
69.7
0.79
Week
Linear”**
1
13.8
0.22
58.1
0.94
Quad.+**
206
409
1193
2
15.4
0.24
64.8
1.00
4 7 7
306
650
3
16.3
0.23
68.4
0.95
421
211
349
4
17.4
0.23
72.9
0.95
272
185
478
5
77.0
0.22
71.2
0.93
263
288
628
6
17.7
0.22
73.6
0.94
625
583
788
7
77.2
0.24
71.6
1.03
1592
1129
847
--
230
Fall, Pearson and Femandez-Rivera
observed as illustrated by the following regression
equations of M (kg) on time (60 days [D] after work):
M = 257 (s.e. 12) + 0.825 (s.c. 0.054) X D for oxen in
‘poor’ IBC (at the start of the experiment), M = 302
(s.e. 12) + 0.967 (s.e. 0.041) X D for oxen in ‘medium’
Power
IBC (at the start of the experiment), M = 303 (se. 11)
Sp”d
I’ower
w per
+ 0.870 (s.e. 0.037) X
Source of variation
D for oxen in ‘good’ IBC (at the
(m/s)
W)
100 kg M)
start of the experiment).
Initial body condition
‘Poor’
(1~91
637
117
The overall rate of change of M was similar
‘Mcdium’
W8h
637
107
irrespective of the IBC score. However oxen in ‘poor’
‘Good’
0.96
780
118
and ‘medium’ IBC had higher M gains (3,2Og/day
S.C.
0~005
1
0.6
per kg M) than oxen in ‘good’ IBC (2.87 g/day per kg
Lap
M). Oxen in ‘poor’ and ‘medium’ IBC were able to
1
0.95
706
317
reach their initial live weight 4 weeks, on average,
2
0~97
722
120
after work stopped. It took 6 weeks alter the
3
047
724
120
cessation of work for oxen in ‘good’ IBC to reach
4
0.95
706
117
5
0.92
690
115
their pre-work M.
6
0.92
685
114
7
03Y
666
111
IBC did not affect speed of work of teams. Power (W)
8
oa?
651
109
developed by teams in ‘poor’ and ‘medium’ IBC was
9
0437
651
108
similar but significantly lower than power output
10
@87
646
107
(W) of oxen in ‘good’ IBC (P < 0.01). However, when
se.
om
6
1
Week
power was expressed relative to live weight (W per
1
0.78
,590
Y5
100 kg M), the effect of IBC was no longer significant.
2
044
631
103
Three oxen teams with approximately similar M and
3
0+3
653
107
in different body condition (team 1: ‘poor’ IBC,
4
0%
725
120
719 kg, team 2: ‘medium’ IBC, 721 kg; team 3: ‘good’
5
1 al
744
124
IBC, 739 kg) developed similar power output (team
6
0%
713
120
1: 775 W; team 2: 697 W; team 3: 741 W).
7
0.99
739
126
se.
0.07
5
1
Differences in speed and power output due to week
of work were significant (P < 0.01, Table 2). Speed
Early in lactation increases in DM intake were seen
and power output increased steadily over weeks for
in cows with a Iow body condition as compared with
a11 teams irrespective of their IBC. Even though oxen
those in a better body condition (Jones and
lost body weight throughout the experiment, there
Garnsworthy, 1989). As suggested by Faverdin rf nl.
was a significant weekly increase of 0.035 m/s and
(1995), undernutrition induces an increase in food
25.1 W in speed and power, respectively.
intake when food unavailability is no longer a
limiting factor.
Lap number had a significant effect (P < 0.01) on
speed and power output. Two contrasting phases
The steady increase in food intake and power output
were observed in the pattern of power output each
over 7 weeks observed in this study suggests that
day. During the first three laps of work (1st h) there
oxen underwent an adaptation to work during the
was an increase of 0.07 m/s and 9 W in speed and
first days of work. They became more adapted as
power each lap. In the second phase starting from
work went on and they were therefore able to
the fourth lap a steady decline in speed and work
increase their intake. Bartholomew ct nl. (1994) also
output of 0.014 m/s and 10.3 W were observed for
attributed increases in speed of working teams over
each lap completed.
time to adaptation to work. Therefore, working
during the dry season would bave the advantage
Discussion
that oxen are fit when cultivation starts and do not
As in previous studies (Fall ci al., 1997) work did not
have to undergo this adaptation period in the
affect intake of millet stover. These results are
cropping season.
consistent with most other studies that indicated no
differences i n i n t a k e i n w o r k i n g animais a s
During the preparation phase of the experiment oxen
compared with animais at-rest (reviewed by Pearson
were given food to reach the targeted body condition
and Dijkman, 1994). Poor body condition bcfore
and live wcight. This was however difficult t o
work was conducive to higher intake of millet stover
achieve because live-weight changes were associated
than good body condition before work over 7 weeks.
with changes in body condition. At the start of the
Nutrition of draught cattle - 3
231
experiment heavier animals tended to have better
820 N (Khibe and Bartholomew, 1993). They could
body condition than lighter animals. In order to
however pull heavily loaded carts without undue
minimize the confounding effect of M and IBC on the
stress.
rate of work (W) in different treatment groups,
power output was expressed relative to M (W per
It was expected that weight losses would adversely
100 kg M). The use of power relative to M to
affect work output. In this experiment power output
investigate the effect of IBC on work performance
improved over weeks while oxen were undergoing
was based on the assumption that oxen in ‘good’ IBC
weight losses. The same trends in live-weight change
had a higher fat content per kg M than oxen in ‘poor’
and power output were reported by Bartholomew et
or ‘medium’ IBC.
nl. (1993). Therefore the weight losses oxen cari
tolerate before work output is affected are difficult to
Power output is a function of speed and draught
estimate. Continuous and severe weight losses cari
force. The latter was set in this experiment to be
compromise the health of the animal, or even its life.
proportional to M. Therefore any advantage of oxen
However in this experiment, oxen were able to
in good condition over those in poor condition
regain live weight at a rapid rate when they had
would have been expressed as a higher average
access to good quality pasture during the rainy
walking speed. As compared with oxen in poor
season. It took them 4 to 6 weeks to reach their
condition, oxen in good condition would perform
pre-work live weight.
work at a higher rate or for a longer period of time
because they would bave more body reserves to
At the start of the cropping season, various body
draw on to fuel muscle activity. However walking
conditions are found in oxen because of differences
speed was not significantly affected by body
in food resources, management practices and the
condition in this experiment. Furthermore, the effect
disease situation in farming systems in the semi-arid
of IBC on power output was no longer significant
zone. Observations from this study suggest that a
when power output was expressed in relation to M.
body condition score of between 2 and 3 as defined
The similarity of power output relative to M for a11
by Nicholson and Butterworth (1986) would be a low
oxen suggested that animals with same body mass,
critical score below which work may irreversibly
irrespective of fat content, generated the same power
damage the oxen’s health. The ideal body condition
output This suggests that power output is more
score would range between 4 and 6. These animais
dependent on body mass than body condition. Oxen
are not too fat nor too lean and cari perform well if
in good condition did not out-perform oxen with
they are in good health. Oxen with a body condition
equal M but in poor body condition. These results
score of over 6 may be too fat to move comfortably
are consistent with those reported by Bartholomew et
and are more susceptible to heat stress than leaner
nl. (1994). These authors evaluated the relative
oxen. Moreover, the feeding level required to reach a
importance of body weight and body condition on
body condition score over 6 is unlikely to be
work performance by applying the same load of
profitable as far as feeding for work performance is
367 N to groups of oxen weighing 310 and 360 kg
concerned.
and in good and poor condition. Light oxen in good
condition could not sustain the work level applied.
Oxen should be supplemented during the cropping
They concluded that live weight rather than body
season when work is performed for more than 6
condition is the single most important determinant
weeks. If the working period is short, weight losses
of work output. Therefore, it seems that farmers
could be tolerated as animais will regain their live
should be encouraged to Select large-framed animais
weight rapidly. Supplementary feeding is however
for draught purposes. This may be constrained by
worthwhile for animals scheduled to be sold for
the fact that more Young animals are being used for
meat after work, even for short working periods, SO
draught purposes with a rapid on-farm turn-over
that work does not adversely affect their market
rate of these animals, apparently driven by an
value. In
semi-arid
west
Africa
food
attractive meat market. There is therefore a genuine
supplementation under these circumstances may be
need to investigate feeding and management
based on whole cotton seed, groundnut, sesame or
practices that Will optimize power and meat output
cotton cakes if available. These foods are rich in
in these farming systems.
protein and energy and provide substrates
(long-chain fatty acids, glycogenic compounds) that
Good IBC may allow work for longer periods of time
cari be directly used for work.
in the cropping season. In the present study, oxen in
‘poor’ IBC sustained average draught forces of
Acknowledgements
682 N. These animals might not be able to perform
The
authors
thank
the
Overseas
Development
ploughing or ridging for extended periods because
Administration (ODA) of the United Kingdom and the
these two activities require draught forces of about
International Livestock Research Institute for funding this
232
Fall, Pearson and Fernhdez-Rivera
study and E. A. Hunter for statistical advice during
Jones, G. P. and Garnsworthy, P. C. 1989. The effects of
prepnration of the manuscript,
dietary energy content on the response of dairy cows to
body condition at calving. A~~imnl Pmdurtim 49: 183-191.
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