I. Mecha and T.A. Adegbola
Department of Animal Science University of Nigeria
Nsukka, Nigeria
Goats occupy a very important position in the farming system of most countries of Africa, Asia and Latin America because they are easily adaptable to varying conditions such as availability of food and water and their ability to feed on a wide range of grasses and browse plants. They are found in the forest, savanna and arid areas of the world. More than two-thirds of the estimated world population of goats (391 million) are found in the tropics and sub-tropics (FAO, 1973). The most important centres for goat-keeping are in Africa where in certain countries (Niger, Mauritania and Somalia) more than one goat is kept per person (FAO, 1973). Goats are kept mainly for meat although also for milk in Niger and skins in Nigeria. There are some 22.4 million goats in Nigeria and this is exceeded only by India with a goat population of 69.2 million (FAO, 1973). Moreover, the FAO (1966) found that goats provided over 25% of total lean meat consumed in Nigeria between 1963 and 1964.
The feeding habits and feed preferences of goats have been little studied though they are observed to consume, besides grass, leaves, twigs, shoots, barks and aromatic herbs. Wilson (1957) found that in an arid area of Kenya, goats spent more than 50% of their feeding time eating from shrubs and trees, and many people have concluded that goats have a preference for feeding stuffs relatively rich in crude fibre. The present report is an analysis of some forages (browse plants and grasses) consumed by goats in southern Nigeria. This knowledge is necessary in order to understand the habits of goats as well as to explore the possibility of cultivating browse plants for goats and to keep existing species from becoming extinct.
The browse plants analysed are those which are either cut for feeding sheep and goats by farmers or those which are observed to be eaten by them. The plants were collected between July and August, 1978, and their local and botanical names were identified. The parts eaten (leaves in the case of trees and shrubs and leaves and stems in the case of herbs and grasses) were analyzed. They were oven-dried at 100°C for 24 hours and the proximate components (crude protein, crude fibre, ash and ether extracts) were determined by the AOAC (1970) methods.
The percentage dry matter (DM) was the same in the forages with a range of between 31.4% and 34.2% and a mean of 33.1 (+0.60) (Table 1). The protein content of the trees, shrubs and herbs is higher than that of the grasses. The value for the trees is higher than the values 9.4 to 16.9% obtained for Australian browse trees by Wilson (1977), and lies within the range 8.8% to 22.8% obtained for trees and shrubs in Australia by McLeod (1973). The protein value for shrubs is similar to the values given by Wilson (1977) but the herbs reported by him had a higher protein content (23.1%) than in the present report. Majumdar, Momim and Kehar (1967) showed that locality affects the chemical composition of tree leaves used as cattle fodder. McLeod (1963) reported that season had no effect on the digestibility of some browse plants but that it affected the digestibility of others. Wilson (1977) showed that shrubs in some areas of Australia were remarkable in retaining their high N content and digestibility throughout dry periods in contrast to the low value of mature annual grasses, and that trees had lower nutritional value than the shrubs. Wilson, Leigh, Hindley and Mulham (1975) showed that goats could utilize browse plants of the semi-arid woodland of New South Wales and that the diet of goats consisted chiefly of browse, whereas sheep showed preference for pasture species. There were also species differences in browse intake. Wilson (1957) observed that goats in an arid location in Kenya spent more than half their feeding time eating from shrubs and trees, and it has been inferred that goats have a preference for feeding stuffs rich in crude fibre (De Haas and Horst, 1979). The browse trees and shrubs analyzed in the present report have lower fibre contents than the grasses. Any preference goats have for browse plants will not be due to the high fibre content of browse trees; it may in fact be due to their high protein content or other contents such as aromatic compounds and other compounds of medicinal importance.
Table 1 The chemical composition of some southern Nigerian forages used for feeding local sheep and goats
S/No |
Vernacular Names |
Common Names |
Scientific Names |
% Dry Matter |
% Crude Protein |
% Ether Extract |
% Crude Fibre |
% Ash |
% Silica |
% Nitrogen-Free Extracts |
TREES | ||||||||||
1. |
Ahaba |
– |
Acacia (Hook f.ex Oliv) Engl. |
29.93 |
11.16 |
0.80 |
23.80 |
7.00 |
3.40 |
57.24 |
2. |
Ngwu |
– |
Albizzia ferrunginea (Guilt & Perr) Benth |
14.48 |
37.87 |
1.00 |
40.70 |
5.00 |
1.10 |
15.43 |
3. |
Kashu |
Cashew |
Anacardium Occidentale Linn. |
29.59 |
15.54 |
1.50 |
24.50 |
3.00 |
1.30 |
55.46 |
4. |
Ubeagba |
– |
Canadum Schweinfurtii Engl. |
46.15 |
11.16 |
2.00 |
25.40 |
5.00 |
1.20 |
56.44 |
5. |
Akwu |
Cotton tree |
Ceiba pentandra (Linn.) Gaertn. |
30.78 |
12.92 |
1.80 |
19.50 |
6.00 |
0.40 |
59.78 |
6. |
Orji |
Iroko |
Chlophora excelsa (Welw.) Benth. |
33.46 |
17.73 |
4.80 |
12.74 |
6.54 |
0.40 |
58.19 |
7. |
Oroma |
Orange |
Citrus sp. |
55.22 |
20.14 |
1.90 |
26.78 |
9.00 |
2.00 |
42.18 |
8. |
Ube |
Pear leaves |
Dacryodes edulis (G. Don.) H.J. Lam |
35.77 |
20.58 |
0.70 |
20.00 |
9.40 |
4.00 |
49.32 |
9. |
Icheku |
Velvet Tamarind |
Dialum guineense Willd |
25.30 |
24.96 |
2.10 |
36.20 |
9.00 |
3.40 |
27.74 |
10. |
Igu nkwu |
Oil Palm leaves |
Elaeis guineensis Jacq |
50.13 |
12.48 |
6.50 |
29.80 |
7.00 |
3.00 |
44.22 |
11. |
Ogbu |
– |
Ficus elasticoides De Willd |
52.55 |
14.89 |
4.70 |
21.50 |
12.50 |
2.50 |
46.41 |
12. |
Oturu |
– |
Harungana madagascariensis Lam.ex Poir |
20.30 |
13.35 |
3.80 |
16.90 |
4.54 |
0.30 |
61.41 |
13. |
Mangolo |
Mango |
Mangfera indica. Linn. |
19.17 |
10.07 |
1.30 |
30.50 |
5.00 |
1.80 |
63.13 |
14. |
Akwukwo Ogede |
Plantain leaves |
Musa sapientum |
35.66 |
19.92 |
1.00 |
24.10 |
10.50 |
5.86 |
44.48 |
15. |
Ugba |
Oil Bean |
Pentachethra macrophylla Benth. |
23.76 |
18.39 |
3.10 |
22.80 |
2.00 |
1.30 |
53.71 |
16. |
Guova |
Guava |
Psidium guajava Linn. |
36.03 |
10.51 |
1.00 |
20.00 |
1.00 |
0.40 |
67.49 |
17. |
Mgbugba (Nsukka) |
– |
Rauwofra vomitoria Afzel. |
27.56 |
27.14 |
4.50 |
9.30 |
5.20 |
4.10 |
53.86 |
18. |
Okwe |
(African Wood oil) (Nut tree) |
Ricinodendron heudelotiL Muell |
29.35 |
12.04 |
1.60 |
17.40 |
8.00 |
3.15 |
60.96 |
19. |
Ijikara |
– |
Spondias mombin Linn. |
49.78 |
18.83 |
5.30 |
13.00 |
4.50 |
0.90 |
58.37 |
20. |
Utoko Nsukka |
– |
Sterculia tragacantha Lindl. |
36.51 |
17.07 |
2.70 |
23.70 |
7.50 |
0.50 |
49.03 |
21. |
Ukwa |
African Bread . |
Treculia africana Decne. |
23.74 |
15.76 |
6.30 |
17.60 |
4.50 |
1.15 |
55.84 |
SHRUBS | ||||||||||
22. |
Agbarugba (Nsukka) |
Xmas Bush |
Alchornea cordifolia |
17.76 |
22.99 |
1.40 |
15.60 |
11.00 |
4.90 |
49.01 |
23. |
Abosi |
Baphia nitida |
41.49 |
24.30 |
6.10 |
11.30 |
4.00 |
0.50 |
54.30 | |
24. |
Agbugbu (Nsukka or Viovo Umuahia) |
Pigeon Pea |
Cajanus Cajan (Linn.) Millsp. |
36.74 |
29.77 |
6.80 |
24.90 |
4.00 |
1.30 |
34.53 |
25. |
Anyachu (Nsukka) |
– |
Glyphaea brevis (spreng.) Monachino |
25.44 |
18.61 |
4.10 |
18.20 |
8.00 |
4.40 |
51.09 |
26. |
Owu |
Cotton Plant |
Gossypium barbadense Linn. |
27.29 |
12.26 |
9.30 |
7.80 |
3.80 |
3.40 |
66.84 |
27. |
Leucaena leucocephala (lam) de Wit |
19.00 |
25.61 |
8.20 |
12.40 |
5.00 |
0.90 |
48.79 | ||
28. |
Akwukwo Akpu |
Cassava leaves |
Manihot utilissima Pohl. |
41.84 |
31.52 |
7.70 |
17.40 |
3.50 |
1.90 |
39.82 |
29. |
Olugbu Agu (Nsukka) |
Waltheria indica Linn. |
41.99 |
13.13 |
3.10 |
16.80 |
9.50 |
9.00 |
57.47 | |
HERBS | ||||||||||
30. |
Oranjila |
Haemorrhage Plant |
Aspilia africana |
36.12 |
19.92 |
2.00 |
11.40 |
3.90 |
0.90 |
62.78 |
31. |
Agbara (Nsukka) |
– |
Calopogonium mucunoides Desv. |
25.36 |
24.08 |
3.10 |
21.60 |
9.80 |
3.92 |
41.42 |
32. |
Okpete |
Ginger-Lily |
Costus afer Ker-Gawl |
45.41 |
16.86 |
2.70 |
21.20 |
11.00 |
2.40 |
48.24 |
33. |
Ogbaraohu |
– |
Eupatorium oforatum Linn. |
44.48 |
20.58 |
3.80 |
9.30 |
7.60 |
0.60 |
58.72 |
34. |
Mgbambirim (Nsukka) |
– |
Justicia spp. |
36.79 |
22.77 |
2.00 |
14.00 |
12.00 |
3.50 |
49.23 |
35. |
Okochi (Nsukka) |
– |
Justicia spp. |
33.95 |
18.17 |
6.60 |
22.50 |
8.00 |
1.40 |
44.73 |
36. |
Ebarintakpo Ocha |
– |
Sida Stipulata cav. |
23.74 |
19.92 |
1.30 |
15.20 |
3.90 |
1.20 |
59.68 |
37. |
Ebarintakpo Oji (Dark) (Nsukka) |
– |
Sida spp. |
33.02 |
13.57 |
3.60 |
14.20 |
12.00 |
2.20 |
56.63 |
38. |
– |
– |
Synedrella nodiflora Gaertn. |
26.54 |
21.67 |
2.40 |
13.60 |
12.00 |
11.60 |
50.33 |
39. |
Udo |
– |
Urena lobata Linn. |
20.60 |
15.32 |
2.00 |
17.60 |
6.00 |
3.90 |
59.08 |
40. |
Agbara Oyibo |
Cow Pea |
Vigna unguiculata (Linn.) Walp. |
38.46 |
11.82 |
1.50 |
18.20 |
6.10 |
0.90 |
62.38 |
GRASSES | ||||||||||
41. |
– |
Gamba grass |
Andropogon tectorum Schum & Thonn. |
32.08 |
11.82 |
2.50 |
29.30 |
6.00 |
2.00 |
50.38 |
42. |
Achara |
Bamboo |
Bambusa vulgads Wendel |
46.66 |
19.48 |
1.80 |
28.20 |
11.04 |
1.40 |
39.48 |
43. |
Achara | Elephant grass |
Pennisetum purpureum |
26.79 |
13.13 |
2.00 |
34.40 |
6.79 |
2.30 |
43.68 |
44. |
Oka |
Maize |
Zea mays Linn. |
31.44 |
15.32 |
2.80 |
23.20 |
8.00 |
3.80 |
50.68 |
Table 2 The mean values of proximate components of forages eaten by goats
Chemical Components |
Forages |
Mean (±SE) | |||
Trees |
Shrubs |
Herbs |
Grasses |
||
Dry Matter |
33.58 |
31.44 |
33.13 |
34.24 |
33.10±0.60 |
Crude proteina |
17.26 |
22.27 |
18.61 |
14.94 |
18.27±1.53 |
Ether extractsa |
2.78 |
5.84 |
2.82 |
2.28 |
3.43±0.81 |
Crude Fibrea |
22.68 |
15.55 |
16.25 |
28.78 |
20.82±3.10 |
Asha |
6.29 |
6.10 |
8.39 |
7.96 |
7.19±0.58 |
Silicaa |
2.01 |
3.29 |
2.96 |
2.38 |
2.66±0.29 |
Silica-free asha |
4.28 |
2.81 |
5.43 |
5.58 |
4.53±0.64 |
Nitrogen-free extractsa |
50.99 |
50.24 |
53.93 |
46.04 |
50.30±1.63 |
aThe proximate components are expressed on dry matter basis.
The significance of the higher ether extract of shrubs is not understood. However, if a good percentage of it is true fat then the shrub leaves are expected to have a higher energy content than are trees or grasses.
The shrubs have the highest content of silica and the lowest silica-free ash. The generally high protein values and low fibre values in browse trees, shrubs and herbs may be an advantage to browsing sheep and goats, especially during the dry season when the nutritive values of tropical grasses are usually low due to decreased protein and increased fibre level (Oyenuga, 1957).
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