Livestock Research for Rural Development 12 (1) 2000

Citation of this paper

Effect of tethering feeding system on the performance of West African dwarf goats

P O Ogebe, A O Ogwu, B S Mustafa and L R McDowell*

Department of Animal Production, University of Agriculture, Makurdi
* Animal Science Department, University of Florida, Gainesville, FL, USA 32611


Abstract

An experiment was conducted for 56 days with growing West African Dwarf goats to evaluate the effects of tethering feeding management on body weight and development during the 1998 cropping season in Benue State, Nigeria. Changes (mm\kgW.75\day) in withers height were similar (P>0.05) in male (0.12±0.04) and female (0.15±0.05) goats. Female animals showed superior body weight changes (2.70±0.95g\kgW.75\day), and in overall better thoracic girth (0.17±0.06) compared to the values of 0.84±0.30g\kgW.75\day and 0.04±0.01 for the males, respectively. Both male and female goats showed a high degree of selectivity, observed by the goats smelling forage species with the nose.

The goats did not thrive exclusively on grass, but fed also on browse. Peak grazing activities were between 0800-1000 hours, while at noon (1200-1400 hours), light browsing, resting or rumination were observed. In the evening (1400-1600 hours), light grazing predominated. Light rains did not affect grazing behavior of the goats but foraging behavior was affected by heavy rains and excessively sunny days.

Close observation or supervision were found to disturb the grazing habit of the goats, with males more easily frightened than the females. Both sexes have a marked ability to identify pasture species of high palatability. Forage species not more than 45 cm tall were most preferred as the goats spent more time grazing them.

For optimum productivity, West African Dwarf goats managed under tethering may be tethered in locations of both grass and browse plants. Also, to minimize the adverse effect of heat or heavy rain, it is suggested that tethered animals be left at the grazing area for only their active grazing hours.

Keywords: West African Dwarf goats, grazing, browsing, tethering, foraging behavior, Nigeria


Introduction

Problems encountered in the traditional management system of small ruminants, especially in purely arable environments have been enumerated (Otchere and Kallah 1990). One of the modification strategies advocated for the typical free-roaming characteristics of animals in the traditional system is the tethering feeding method which confines the animals within a restricted location for grazing. Available information indicates that the tethering feeding system is used to restrain the animal to avoid crop damage. For example, Francis (1988) reported that some flocks were controlled by tethering to avoid crop damage during the cropping season in south East Nigeria. In the Northern parts of Nigeria, Otchere and Kallah (1990) reported that animals which escaped from tethering and broke into fenced crop fields had damaged crops and resulted in feuds and payment of compensation. Goats were often tethered by neck loops to pickets under shelter at night while sheep were reported to spend the night often tied by neck loops to 'dangwali,' a rope tied between two pickets. However, sufficient data on animal performance under the tethering feeding system is grossly lacking.

The purpose of this study was to assess the performance and behavior of the West African Dwarf goats under the tethering feeding management.


Experimental procedures

Experimental animals

Six growing West African Dwarf goats comprising three intact bucks aged between 7-8 months and weighing between 6.00 and 6.02 kg (mean 6.00±0.02 kg), and three non-cyclic does aged between 7 and 8 months and weighing between 6.00 and 6.01 kg (mean 6.01±0.01 kg) were used to evaluate growth and development of the goats under tethering feeding system. Animals were sourced using the criteria of Ogebe et al (1995) and adjusted for restriction by the method of Ogebe et al (1996).

Management of animals

In a preliminary trial conducted for 7 days, animals were led out to abandoned plots and roadside forages consumed by them were identified. During the experimental period which lasted for 56 days (between June and August) of the 1998 rainy season, experimental goats were tied by the neck with about 40 cm of rope and led out at 0800 h and randomly tied to pickets at the grazing area consisting of five major forage species (Table 1). Animals were returned to separate pens at 1800 h daily and weighed before being provided with fresh, cool water.

Records

Animals were observed twice daily between 0800 h and 0900 h and 1700 h and 1800 h for feeding behavior. Weekly bodyweight changes were recorded in the morning on an empty stomach. Thoracic girth was measured as the smallest circumference of the body immediately behind the shoulders, while withers height was recorded as the  vertical distance between ground to point of withers.

The data were subjected to analyses of variance; Duncan's Multiple Range test was used to compare treatment means (Snedecor and Cochran 1980).


Results and discussion

Forage chemical composition

Table 1 presents the proximate composition of the forage consumed by the goats.

Table 1: Chemical composition of forage consumed in the study area

Forage
Sample

Dry Matter
%

Crude protein,
%DM

Ether extract, %DM

Crude fiber, %DM

Ash, 
%DM

NFE, 
%DM

Itch Grass

65.0

8.2b

12.4a

37.4a

10.7

26.4ab

Panicum

70.6

14.4a

9.0b

39.8a

8.4

24.1b

Bracharia

65.9

11.7a

11.9a

30.0b

9.8

30.5a

Eleusine

64.5

13.4a

12.6a

34.5ab

8.4

26.3ab

Almond leaves

58.0

14.8a

11.0a

38.8a

9.4

29.9a

a,b: Means in a column with different superscripts differ (P<0.05)

It was observed that animals spent more time eating itch grass (Roattboella cochinchinensis) although this was most scanty and contained the lowest protein content (Table 1) compared to other forage species consumed. It is reported that diet selection by rangeland grazers is not simply a factor of forage nutrient composition, but is based on the integration of messages contained in food sensory properties and feedbacks telling on the current nutrition state of the animal or the occurrence of some metabolic disturbances (Narjisse 1991).

Body weight changes

Table 2 presents body weight changes of the goats. In both sexes, the goats did not gain weight for the first 2 weeks of the study, resulting perhaps from bodily adjustment. Also, computed daily weight changes (g\kgW.75\day) showed no particular trend in favor of sex. At the end of 8 weeks of the study, calculated average body weight changes (2.70±0.95g\kgW.75\day) for female goats were higher (P<0.05) than for males (0.84±0.30). This result may be attributable to the better digestibility and utilization of forage by females compared to their male counterpart. It may also be due to the males' extra activity incurring energy loss. Additionally, the males in this study struggled and were more often times strangulated by their ropes compared to their female counterparts which were docile most of the time.

Table 2:  Body weight changes of experimental goats under tethering feeding system

         Weeks

Experimental Goats

Male

Female

kg\W

g\kgW.75\daya

g\W

g\gW.75\daya

Initial

6.01

6.00

1

0.00

0.00

0.00

0.00

2

0.00

0.00

0.00

0.00

3

-0.20

-3.94c

0.00

0.00b

4

0.50

6.22b

0.00

0.00c

5

-0.20

-3.81c

0.20

3.22b

6

0.77

8.22b

0.50

6.04c

7

0.00

0.00c

0.50

6.00b

8

0.00

0.00c

0.55

6.30b

Mean

0.84±0.30c

2.70±0.95b
a: Computed value
b,c: Means (g\kgW.75\day) in a row with different superscripts differ (P<0.5) 
Changes in development

Table 3 depicts the changes in the development of the goats. For withers height (mm\kgW.75\day) development was static in the male goats for the first 2 weeks. Afterwards, positive changes were consistently observed to the end of the study, with an overall computed increment of 3.30 mm in withers height, in relation to the initial height of the goats. For the females, the goats commenced height gains from week 2, displaying an early advantage (P<0.05) over the males to the 4th week. However, overall height changes between the males (0.12±0.04) and females (0.15±0.05) were similar (P>0.05) at the end of the study.

Table 3: Changes in development of experimental goats under tethering feeding system
Weeks (W)

Experimental Goats

Withers Height

Thoracic Girth

Male

Female

Male

Female

cm\W mm\kgW.75\daya

cm\W mm\kgW.75\daya

cm\W mm\kgW.75\daya

 cm\W mm\kgW.75\daya
Initial

30.43

30.00

44.00

43.00
1

0.00

0.00b

0.00

0.00b

0.00

0.00b

-0.05

-0.04c
2

0.00

0.00c

0.30

0.14b

0.50

0.20b

0.35

0.16c
3

0.20

0.11c

0.35

0.16b

-0.25

-0.12c

0.40

0.18b
4

0.20

0.10c

0.35

0.16b

0.00

0.00c

0.48

0.20b
5

0.46

0.19b

0.43

0.18b

0.06

0.04c

0.57

0.22b
6

0.48

0.18b

0.44

0.17b

0.00

0.00c

0.55

0.21b
7

0.48

0.18b

0.50

0.19b

0.10

0.06c

0.55

0.20b
8

0.50

0.18b

0.55

0.20b

0.33

0.13c

0.60

0.21b
Mean

0.12±0.04b

0.15±0.05b

0.04±0.01c

0.17±0.06b

a: Computed Values
b,c: For each development index, means (mm\kgW.75\day) in a row with different superscripts differ (P<0.05)

Mean daily thoracic changes (mm\kgW.75) were more (P<0.05) pronounced in the female compared to male goats, resulted in an overall advantage in heart girth in the female (0.17±0.96) compared to the males (0.04±0.01). This result contrasts with the report of Ayoade (1981) that the height of male Malawian goats less than one year of age was greater than for the females. The use of castrated males by the author might possibly have accounted for the difference compared with the Malawian study.

Grazing observations

The goats showed a high degree of forage selectivity throughout the experimental period, and this was observed by smelling with the nose. This observation is in confirmation with earlier reports (Ogebe et al 1999; Morand-Fehr 1981) that goats are very careful in selecting plant species. The experimental goats did not forage exclusively on grass but also on browse. This was observed as they took large amounts of the leaves of Almond plant present in the experimental area. It could therefore be confirmed from this work that the West African Dwarf goats grazed considerable quantities of grass in agreement with Knight (1965) and also consumed appreciable quantities of browse in agreement with the report of Wilson (1975). The goats grazed more on forage species not higher than their back height from the ground as was observed in their longer grazing time on the pasture where the forage species were not more than 45 cm tall.

When not grazing, the goats preferred nearby shelter as much as the rope tethering them could afford. A few drops of rain did not disturb their grazing until the rains became heavy. This observation, however, contracts with that of Gall (1981) who reported that goats will not tolerate rains and that they run out of the rain at the first few drops. Breed differences might possibly have accounted for the differences in these observations since the West African Dwarf goats appear to be more hardy than many breeds of goats. Indeed, Ikhatua et al (1987) reported a good performance of the West African Dwarf goats in the humid environment of southern Nigeria.

The goats were noticed to be disturbed by close observation within a range of 2-3 metres while grazing, with the males generally more frightened of the intruder than the female. Both sexes have a marked ability to identify pasture species of high palatability as they went straight to some more relished forages (as far as the tethering rope could stretch). This immediate identification of pasture on arrival is similar to reports of Morand-Fehr (1981) that goats on arrival to pasture, quickly begin to graze, but that this intensive grazing does not last for long.

The average grazing period of the West African Dwarf goats without resting was between 0800 hours and 1200 hours, after which they voluntarily stopped grazing and rested. Generally, grazing time was reduced during excessively sunny days, probably resulting from effect of thermal stress on foraging behavior. Also, on excessively wet days, resulting from heavy rainfall, goats were sensitive to cold and reduced their grazing activities. Schacht and Malechek (1990) reported that under excessive wet tropical conditions, foraging and overall intake of goats were adversely affected.

Between 1200 and 1400 hours the goats were observed to be resting and ruminating, or standing/lying or playing around. This is in conformity with the observation of Sharafeldin and Shafie (1965) and Hagger (1970) that rumination reaches a maximum at mid-day in sheep and cattle. The main reason for this is perhaps the high ambient temperature which reaches a maximum at mid-day and maintains that level until 1400 hour before falling. In the evening hours (1400 and 1600 hours), the goats exhibited light grazing or resting.


Conclusions

The following conclusions may be made from the study:


References

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Received 24 Sept 1999

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