- Email: [email protected]
Evaluation of arid region browse species from north eastern Nigeria using pen fed goats
Small Ruminant Research 38 (2000) 83±86
Technical note
Evaluation of arid region browse species from north eastern Nigeria using pen fed goats M.S. Yahayaa, J. Takahashia,*, S. Matsuokaa, A. Kibonb, D.B. Dibalb a
Department of Animal Science, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan b Department of Animal Science, University of Maiduguri, Maiduguri, Nigeria Received 20 May 1999; accepted 18 February 2000
Abstract Four 18±26 months old castrated Borno whiteSokoto Red goats were used in a 44 Latin square design to measure the dry matter intake (DMI), daily body weight change and dry matter digestibility (DMD) of four native Nigerian browse species, (Ziziphus spinochrist, Wild., Acacia albida, Del., Sterculia satigera, Guill. and Anogeissus licocarpus, Guill.) native to the semi-arid regions. The mean DMI of Z. spinochrist, Wild. and A. albida, Del. were similar but higher than for S. satigera, Guill. and A. licocarpus, Guill. The DMD of A. licocarpus,Guill. was lower (p<0.05) than for Z. spinochrist, Wild., Acacia licocarpus, Del. or S. satigera, Guill. The lowest body weight gain recorded was for A. licocarpus, Guill.; this was attributed to the larger amount of ®bre in the forage resulting in a slow rate of cell wall degradation and rumen digestibility. Goats showed no visual signs of toxicosis. This study suggests that A. albida, Del. has the highest forage value for goats followed by Z. spinochrist, Wild., S. satigera, Guill. and A. licocarpus, Guill. Potentially the species examined can provide feed for goats as well as for other small ruminants during long dry periods when other feed is unavailable. # 2000 Elsevier Science B.V. All rights reserved. Keywords: Browse species; Goats; Semi-arid region; Nigeria
1. Introduction One of the constraint to livestock production in developing countries is having available a constant supply of year round good forage. An inadequate yearly supply of good quality feed forage is common throughout tropical African regions where native pastures and browse from trees are the main forages and in most cases, the only components of livestock nutrition. Lack of improvements in crop yield, incidences of drought and deserti®cation and rampant *
Corresponding author. Tel.: 81-155-49-5421; fax: 81-155-49-5462. E-mail address: [email protected] (J. Takahashi)
bush burning have also worsened the availability of livestock feed, especially in the semi-arid areas of this region (Yahaya et al., 1999). The dry season normally lasts for 6±7 months and leads to a rapid decline in the quality and quantity of many forages, thus, resulting in poor animal performance. Livestock reared in these regions may have problems meeting maintenance requirements on dry grass alone and must depend on browse species to supplement their diet in terms of protein, vitamins and minerals (LeHouerou, 1980). Unfortunately some browse from tree forages contain secondary compounds which may be toxic when fed ad lib (FallTaure et al., 1998). The native browse species are palatable and have been found to offer considerable
0921-4488/00/$ ± see front matter # 2000 Elsevier Science B.V. All rights reserved. PII: S 0 9 2 1 - 4 4 8 8 ( 0 0 ) 0 0 1 3 4 - 6
84
M.S. Yahaya et al. / Small Ruminant Research 38 (2000) 83±86
potential while being productive. Traditional herdsmen and other pastoral groups habitually cut down branches from various trees species (Acacia, Adansonia, etc.) making them available to livestock during the dry season when no other forage is available. This study was conducted to assess the nutritive value of four native browse trees as the sole feed for goats during the dry season in the semi-arid region of northern Nigeria. It was assumed that if the browse could be used to sustain goats it might work equally well to supplement diets during periods when herbaceous forage was not available. 2. Materials and methods Four 18±26 months old castrated Borno whiteSokoto Red goats with an initial mean live-weight of 12.40.9 kg were placed in individual metabolism stalls and randomly allocated to one of the four browse species in a 44 Latin square design. Each treatment period consisted of 3 weeks with an adjustment period of 2 weeks preceding each 7 day urine and faeces collection periods. The browse species were all leguminous and consisted of: Ziziphus spinochrist, Wild., Acacia albida, Del., Sterculia satigera, Guill. and Anogeissus licocarpus, Guill. One kilogram (Branches with leaves) were harvested from each browse species from ®ve different plants within the (9 km2 area) Maiduguri area of northeast Nigeria,
about 10 km from the livestock farm (108N, 118S). The 5 kg of the fresh mature browse (stems plus leaves) were then dried outside at air ambient temperature (33±358C) for 24 h. Throughout the study, material was always harvested and dried for 24 h before being fed. The dry material (stem and leaves) was then fed (ad lib) to individual animals at 07:30 and 17:30 hours after the lefts over from previous day were weighed and sub-sampled. The leaf/stem ratios from each branch were determined for each forage species by weighing the air-dried leaves and stems. The liveweight of animals was measured weekly before the morning feeding and after fast from food and water the night prior to the live-weight measurement. Dry matter (DM), organic matter (OM), crude protein (CP), NDF, ADF, Ca and P were analyzed on feed samples, faeces and urine samples from each of the four browse species using techniques described by AOAC (1990) and Van Soest et al. (1991). Hemicellulose content was calculated by subtracting ADF from NDF. All data obtained were subjected to Latin square design ANOVA with means difference determined using Fishers Least Signi®cant Test (Steel and Torrie, 1980). 3. Results and discussion Chemical analyses and leaf/stem ratio of browse species are given in Table 1. The lowest leaf to stem ratio was observed in A. licocarpus, Guill. followed by
Table 1 Mean chemical composition and standard error (S.E.) and leaf to ratios of four browse plant species
Chemical composition (%) DM Omb CP NDF ADF Hemicellulose Ca P Leaves (g) Stems (g) Ratio (leaves/stems) a b
Ziziphus spinochrit, Wild.
Acacia albida, Del.
Sterculia satigera, Guill.
Anogerissus licocarpus, Guill.
S.E.
45 bba 92 c 18 b 53 b 34 b 18 0.11 0.24 148 120 1.2
56 a 87 a 21 a 41 d 22 c 19 0.03 0.12 82 170 0.5
42 c 89 ab 17 b 50 c 32 b 18 0.23 0.22 196 320 0.6
40 c 92 c 12 c 56 a 39 a 17 0.13 0.13 102 260 0.4
3.5 1.2 1.9 3.2 3.6 0.41 0.04 0.03 25 45 0.19
Different letters in the same row indicate signi®cant difference (p<0.05). A 100% dry matter basis.
M.S. Yahaya et al. / Small Ruminant Research 38 (2000) 83±86
85
Table 2 Mean digestibility, dry matter intake (DMI) and daily gain with standard error (S.E.) for four browse plant species fed to goats Digestibility (%)
Ziziphus spinochrit, Wild.
DM CP NDF ADF Hemicellulose DMI (g/day) Daily gain (g)
70 69 57 48 73 790 167
a
aa b b b a a a
Acacia albida, Del.
Sterculia satigera, Guill.
Anogerissus licocarpus, Guill.
S.E.
74 79 65 64 70 850 167
74 67 51 50 49 570 155
61 66 42 41 49 540 155
3.1 3.0 4.9 4.8 6.5 77.7 3.4
a a a a a a a
a b b b b b b
b b c c b b b
Different letters in the same row indicate signi®cant difference (p<0.05).
A. albida, Del. The DM and CP contents of A. albida, Del. were higher (p<0.05) than those for the other three species evaluated. While the NDF, ADF, Ca and P contents in the other species were higher (p<0.05) than for the A. albida, Del., the hemicellulose content in A. albida, Del. and A. licocarpus, Guill. were higher (p<0.05) than those of Z. spinochrist, Wild. and S. satigera, Guill. The DM, CP and OM contents of the four browse species evaluated were similar to those reported in A. albida by ILCA (1988). The NDF and ADF values obtained from the browse species, except that of A. albida, Del. are higher in the present study than the 40 and 30% obtained from Robinia pseudoacacia (Black Locust Leaf) meal reported by Ayers et al. (1996). Digestibility, DM intake and daily gain in goats are shown in Table 2. Relatively higher (p<0.05) digestibility coef®cients were observed for CP, NDF and ADF in the A. albida, Del. compared to those of the other browse species. Previous reports have shown that the intake of browse trees depended on palatability, tannin, cell wall contents (ADF) and the physiological status of the animals (Mandibaya and Chihora, 1999). Leguminous plants, like A. albida, Del. have been reported to have moderate levels of tannin (LeHouerou, 1980). In the present study, the highest DMI and apparent digestibility of DM, CP, NDF and ADF were recorded in A. albida, Del. followed by Z. spinochrist, Wild., S. satigera, Guill. and Anogeissus licocarpus, Guill. The A. albida has relatively lower NDF and ADF contents, but higher CP contents compared to those for the other species evaluated (p<0.05). These characteristics may be responsible for the higher intake and digestibility observed in the A. albida, Del. in comparison with
the other three diets evaluated. The lower DMI and DMD observed in A. licocarpus, Guill. compared to the three species may be linked to low CP content and NDF digestibility associated with the higher proportion of stems to leaves while the animals prefer the leaves to the stems when given the choice. Our DMI (850 g/day) was more than twice the value of 401 g/ day obtained when Menz rams were fed A. albida, Del. in Ethiopia (Tanner et al., 1990). The DMI for Z. spinochrist, Wild. was similar to that for A. albida, Del. but higher (p<0.05) than for S. satigera,Guill. and A. licocarpus, Guill. which did not differ (p>0.05) (Table 2). The daily gain from A. albida, Del. and A. licocarpus, Guill. was higher (p<0.05) than that from Z. spinochrist, Wild. and S. satigera,Guill. Mean DMD among all four species was slightly higher than the value of 63% DMD reported by Norton et al. (1972) when sheep were fed Acacia aneura, Del. in Australia. Furthermore, the DMD was 37% higher than the value obtained when goats were fed Acacia leaves in Korea (Kong et al., 1979). The mean CP digestibility is comparable to the value of 77% reported by ILCA (1988) when cattle were fed Acacia africana, Del. in the Accra plains of Ghana. The daily gain of the goats fed on A. licocarpus, Guill. and S. satigera, Guill. was lower (p<0.05) than for the other two browse species (Table 2). This decreased daily gain from A. licocarpus, and S. satigera Guill. may be attributed to the lower DMI compared to the other browse species evaluated. Feeding with A. albida, Del. resulted in the highest daily gain as re¯ected by the high values of DMI and DMD (p<0.05). This higher value of daily gain that resulted from feeding A. albida, Del. may be linked to a lower cell wall content, coupled with the high values of CP and NDF
86
M.S. Yahaya et al. / Small Ruminant Research 38 (2000) 83±86
digestibility. In the current study, no signs of toxicity were observed among animals throughout the study period. Similarly, no symptoms of toxicity have been observed when goats and steers were offered leguminous tree forages in Harare, Zimbabwe (Florence et al., 1998). Based on these data it would appear that the browse species evaluated in this research could be used either as a supplement or as a basal diet when herbaceous forage is limiting the production potential of goats and possibly other ruminants. Further research is needed to ascertain the viability of using these browse species on a long-term basis or what quantities constitute an optimum supplementary feed for small ruminants.
References A.O.A.C., 1990. Association of Of®cial Analytical Chemists, 16th revised Edition. In: A.O.A.C. (Ed.), Of®cial Methods of Analysis. Washington, DC. pp. 210±240. Ayers, A.C., Barrett, R.P., Cheeke, P.R., 1996. Feeding value of tree leaves (hybrid poplar and black locust) evaluated with sheep, goats and rabbits. Anim. Feed Sci. Technol. 5, 51±62. Fall-Taure, S., Michalet-Doreau, B., Traore, E., Friot, D., Richard, D., 1998. Occurrence of digestive interactions in forage-based diets for sheep. Anim. Feed Sci. Technol. 74, 63±78. Florence, V., Ndlovu, L.R., Dzowela, B.H., 1998. Utilization of Leucaena divesifolia, Leucaena esculenta, Leucaena pallida
and Calliandra calothyrsus as nitrogen supplements for growing goats fed maize stover. Anim. Feed Sci. Technol. 74, 15±28. ILCA (International Livestock Center for Africa), 1988. Forage outreach in sub-humid west Africa. ILCA Newslett. 2, 7±12. Kong, H.S., Yoo, T.S., Ghois, S.Y., 1979. A study on the nitrogen metabolism and energy digestibility with Korean goats fed Acacia leaves. Korean J. Dairy Sci. 1, 35±44. LeHouerou, H.N., 1980. The role of browse in the Sahelian and Sudanian zones. In: LeHouero, H.N. (Ed.), Browse in Africa. ILCA, Addis Ababa, pp. 83±102. Mandibaya, W., Chihora, R.M., 1999. The nutritional value of Piliostigma thonninghii (Mutukutu, Monkey bread) pods as a feed supplement for communal cattle in Zimbabwe. Anim. Feed Sci. Technol. 78, 287±295. Norton, B.W., Rohan-Jones, W., Ball, F., Long, R.A., Murray, R.M., 1972. Nitrogen metabolism and digestibility studies with merino sheep given Acacia aneura and native pasture. Proc. Aust. Soc. Anim. Prod. 9, 346±349. Steel, R.G.D., Torrie, J.M., 1980. Principles and Procedures of Statistics, 2nd Edition. McGraw Hill, New York, pp. 36±48. Tanner, J.C., Reed, J.D., Owen, E., 1990. The nutritive value of fruits (pods with seeds) from four Acacia species compared with extracted noug (Guizotia absyssinica) meal as supplements to maize stover for Ethiopia highland sheep. Anim. Prod. 51, 127±133. Van Soest, P.J., Robertson, J.B., Lewis, B.A., 1991. Methods for dietary ®ber neutral detergent ®ber and non starch polysaccharides in relation to animal nutrition. J. Dairy Sci. 74, 3583±3597. Yahaya, M.S., Takahashi, J., Matsuoka, S., Kibon, A., 1999. Effect of supplementary feeding of cotton seed cake on feed intake, water consumption and work output of work bulls in Borno state, Nigeria. Anim. Feed Sci. Technol. 79, 137±143.
Technical note
Evaluation of arid region browse species from north eastern Nigeria using pen fed goats M.S. Yahayaa, J. Takahashia,*, S. Matsuokaa, A. Kibonb, D.B. Dibalb a
Department of Animal Science, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan b Department of Animal Science, University of Maiduguri, Maiduguri, Nigeria Received 20 May 1999; accepted 18 February 2000
Abstract Four 18±26 months old castrated Borno whiteSokoto Red goats were used in a 44 Latin square design to measure the dry matter intake (DMI), daily body weight change and dry matter digestibility (DMD) of four native Nigerian browse species, (Ziziphus spinochrist, Wild., Acacia albida, Del., Sterculia satigera, Guill. and Anogeissus licocarpus, Guill.) native to the semi-arid regions. The mean DMI of Z. spinochrist, Wild. and A. albida, Del. were similar but higher than for S. satigera, Guill. and A. licocarpus, Guill. The DMD of A. licocarpus,Guill. was lower (p<0.05) than for Z. spinochrist, Wild., Acacia licocarpus, Del. or S. satigera, Guill. The lowest body weight gain recorded was for A. licocarpus, Guill.; this was attributed to the larger amount of ®bre in the forage resulting in a slow rate of cell wall degradation and rumen digestibility. Goats showed no visual signs of toxicosis. This study suggests that A. albida, Del. has the highest forage value for goats followed by Z. spinochrist, Wild., S. satigera, Guill. and A. licocarpus, Guill. Potentially the species examined can provide feed for goats as well as for other small ruminants during long dry periods when other feed is unavailable. # 2000 Elsevier Science B.V. All rights reserved. Keywords: Browse species; Goats; Semi-arid region; Nigeria
1. Introduction One of the constraint to livestock production in developing countries is having available a constant supply of year round good forage. An inadequate yearly supply of good quality feed forage is common throughout tropical African regions where native pastures and browse from trees are the main forages and in most cases, the only components of livestock nutrition. Lack of improvements in crop yield, incidences of drought and deserti®cation and rampant *
Corresponding author. Tel.: 81-155-49-5421; fax: 81-155-49-5462. E-mail address: [email protected] (J. Takahashi)
bush burning have also worsened the availability of livestock feed, especially in the semi-arid areas of this region (Yahaya et al., 1999). The dry season normally lasts for 6±7 months and leads to a rapid decline in the quality and quantity of many forages, thus, resulting in poor animal performance. Livestock reared in these regions may have problems meeting maintenance requirements on dry grass alone and must depend on browse species to supplement their diet in terms of protein, vitamins and minerals (LeHouerou, 1980). Unfortunately some browse from tree forages contain secondary compounds which may be toxic when fed ad lib (FallTaure et al., 1998). The native browse species are palatable and have been found to offer considerable
0921-4488/00/$ ± see front matter # 2000 Elsevier Science B.V. All rights reserved. PII: S 0 9 2 1 - 4 4 8 8 ( 0 0 ) 0 0 1 3 4 - 6
84
M.S. Yahaya et al. / Small Ruminant Research 38 (2000) 83±86
potential while being productive. Traditional herdsmen and other pastoral groups habitually cut down branches from various trees species (Acacia, Adansonia, etc.) making them available to livestock during the dry season when no other forage is available. This study was conducted to assess the nutritive value of four native browse trees as the sole feed for goats during the dry season in the semi-arid region of northern Nigeria. It was assumed that if the browse could be used to sustain goats it might work equally well to supplement diets during periods when herbaceous forage was not available. 2. Materials and methods Four 18±26 months old castrated Borno whiteSokoto Red goats with an initial mean live-weight of 12.40.9 kg were placed in individual metabolism stalls and randomly allocated to one of the four browse species in a 44 Latin square design. Each treatment period consisted of 3 weeks with an adjustment period of 2 weeks preceding each 7 day urine and faeces collection periods. The browse species were all leguminous and consisted of: Ziziphus spinochrist, Wild., Acacia albida, Del., Sterculia satigera, Guill. and Anogeissus licocarpus, Guill. One kilogram (Branches with leaves) were harvested from each browse species from ®ve different plants within the (9 km2 area) Maiduguri area of northeast Nigeria,
about 10 km from the livestock farm (108N, 118S). The 5 kg of the fresh mature browse (stems plus leaves) were then dried outside at air ambient temperature (33±358C) for 24 h. Throughout the study, material was always harvested and dried for 24 h before being fed. The dry material (stem and leaves) was then fed (ad lib) to individual animals at 07:30 and 17:30 hours after the lefts over from previous day were weighed and sub-sampled. The leaf/stem ratios from each branch were determined for each forage species by weighing the air-dried leaves and stems. The liveweight of animals was measured weekly before the morning feeding and after fast from food and water the night prior to the live-weight measurement. Dry matter (DM), organic matter (OM), crude protein (CP), NDF, ADF, Ca and P were analyzed on feed samples, faeces and urine samples from each of the four browse species using techniques described by AOAC (1990) and Van Soest et al. (1991). Hemicellulose content was calculated by subtracting ADF from NDF. All data obtained were subjected to Latin square design ANOVA with means difference determined using Fishers Least Signi®cant Test (Steel and Torrie, 1980). 3. Results and discussion Chemical analyses and leaf/stem ratio of browse species are given in Table 1. The lowest leaf to stem ratio was observed in A. licocarpus, Guill. followed by
Table 1 Mean chemical composition and standard error (S.E.) and leaf to ratios of four browse plant species
Chemical composition (%) DM Omb CP NDF ADF Hemicellulose Ca P Leaves (g) Stems (g) Ratio (leaves/stems) a b
Ziziphus spinochrit, Wild.
Acacia albida, Del.
Sterculia satigera, Guill.
Anogerissus licocarpus, Guill.
S.E.
45 bba 92 c 18 b 53 b 34 b 18 0.11 0.24 148 120 1.2
56 a 87 a 21 a 41 d 22 c 19 0.03 0.12 82 170 0.5
42 c 89 ab 17 b 50 c 32 b 18 0.23 0.22 196 320 0.6
40 c 92 c 12 c 56 a 39 a 17 0.13 0.13 102 260 0.4
3.5 1.2 1.9 3.2 3.6 0.41 0.04 0.03 25 45 0.19
Different letters in the same row indicate signi®cant difference (p<0.05). A 100% dry matter basis.
M.S. Yahaya et al. / Small Ruminant Research 38 (2000) 83±86
85
Table 2 Mean digestibility, dry matter intake (DMI) and daily gain with standard error (S.E.) for four browse plant species fed to goats Digestibility (%)
Ziziphus spinochrit, Wild.
DM CP NDF ADF Hemicellulose DMI (g/day) Daily gain (g)
70 69 57 48 73 790 167
a
aa b b b a a a
Acacia albida, Del.
Sterculia satigera, Guill.
Anogerissus licocarpus, Guill.
S.E.
74 79 65 64 70 850 167
74 67 51 50 49 570 155
61 66 42 41 49 540 155
3.1 3.0 4.9 4.8 6.5 77.7 3.4
a a a a a a a
a b b b b b b
b b c c b b b
Different letters in the same row indicate signi®cant difference (p<0.05).
A. albida, Del. The DM and CP contents of A. albida, Del. were higher (p<0.05) than those for the other three species evaluated. While the NDF, ADF, Ca and P contents in the other species were higher (p<0.05) than for the A. albida, Del., the hemicellulose content in A. albida, Del. and A. licocarpus, Guill. were higher (p<0.05) than those of Z. spinochrist, Wild. and S. satigera, Guill. The DM, CP and OM contents of the four browse species evaluated were similar to those reported in A. albida by ILCA (1988). The NDF and ADF values obtained from the browse species, except that of A. albida, Del. are higher in the present study than the 40 and 30% obtained from Robinia pseudoacacia (Black Locust Leaf) meal reported by Ayers et al. (1996). Digestibility, DM intake and daily gain in goats are shown in Table 2. Relatively higher (p<0.05) digestibility coef®cients were observed for CP, NDF and ADF in the A. albida, Del. compared to those of the other browse species. Previous reports have shown that the intake of browse trees depended on palatability, tannin, cell wall contents (ADF) and the physiological status of the animals (Mandibaya and Chihora, 1999). Leguminous plants, like A. albida, Del. have been reported to have moderate levels of tannin (LeHouerou, 1980). In the present study, the highest DMI and apparent digestibility of DM, CP, NDF and ADF were recorded in A. albida, Del. followed by Z. spinochrist, Wild., S. satigera, Guill. and Anogeissus licocarpus, Guill. The A. albida has relatively lower NDF and ADF contents, but higher CP contents compared to those for the other species evaluated (p<0.05). These characteristics may be responsible for the higher intake and digestibility observed in the A. albida, Del. in comparison with
the other three diets evaluated. The lower DMI and DMD observed in A. licocarpus, Guill. compared to the three species may be linked to low CP content and NDF digestibility associated with the higher proportion of stems to leaves while the animals prefer the leaves to the stems when given the choice. Our DMI (850 g/day) was more than twice the value of 401 g/ day obtained when Menz rams were fed A. albida, Del. in Ethiopia (Tanner et al., 1990). The DMI for Z. spinochrist, Wild. was similar to that for A. albida, Del. but higher (p<0.05) than for S. satigera,Guill. and A. licocarpus, Guill. which did not differ (p>0.05) (Table 2). The daily gain from A. albida, Del. and A. licocarpus, Guill. was higher (p<0.05) than that from Z. spinochrist, Wild. and S. satigera,Guill. Mean DMD among all four species was slightly higher than the value of 63% DMD reported by Norton et al. (1972) when sheep were fed Acacia aneura, Del. in Australia. Furthermore, the DMD was 37% higher than the value obtained when goats were fed Acacia leaves in Korea (Kong et al., 1979). The mean CP digestibility is comparable to the value of 77% reported by ILCA (1988) when cattle were fed Acacia africana, Del. in the Accra plains of Ghana. The daily gain of the goats fed on A. licocarpus, Guill. and S. satigera, Guill. was lower (p<0.05) than for the other two browse species (Table 2). This decreased daily gain from A. licocarpus, and S. satigera Guill. may be attributed to the lower DMI compared to the other browse species evaluated. Feeding with A. albida, Del. resulted in the highest daily gain as re¯ected by the high values of DMI and DMD (p<0.05). This higher value of daily gain that resulted from feeding A. albida, Del. may be linked to a lower cell wall content, coupled with the high values of CP and NDF
86
M.S. Yahaya et al. / Small Ruminant Research 38 (2000) 83±86
digestibility. In the current study, no signs of toxicity were observed among animals throughout the study period. Similarly, no symptoms of toxicity have been observed when goats and steers were offered leguminous tree forages in Harare, Zimbabwe (Florence et al., 1998). Based on these data it would appear that the browse species evaluated in this research could be used either as a supplement or as a basal diet when herbaceous forage is limiting the production potential of goats and possibly other ruminants. Further research is needed to ascertain the viability of using these browse species on a long-term basis or what quantities constitute an optimum supplementary feed for small ruminants.
References A.O.A.C., 1990. Association of Of®cial Analytical Chemists, 16th revised Edition. In: A.O.A.C. (Ed.), Of®cial Methods of Analysis. Washington, DC. pp. 210±240. Ayers, A.C., Barrett, R.P., Cheeke, P.R., 1996. Feeding value of tree leaves (hybrid poplar and black locust) evaluated with sheep, goats and rabbits. Anim. Feed Sci. Technol. 5, 51±62. Fall-Taure, S., Michalet-Doreau, B., Traore, E., Friot, D., Richard, D., 1998. Occurrence of digestive interactions in forage-based diets for sheep. Anim. Feed Sci. Technol. 74, 63±78. Florence, V., Ndlovu, L.R., Dzowela, B.H., 1998. Utilization of Leucaena divesifolia, Leucaena esculenta, Leucaena pallida
and Calliandra calothyrsus as nitrogen supplements for growing goats fed maize stover. Anim. Feed Sci. Technol. 74, 15±28. ILCA (International Livestock Center for Africa), 1988. Forage outreach in sub-humid west Africa. ILCA Newslett. 2, 7±12. Kong, H.S., Yoo, T.S., Ghois, S.Y., 1979. A study on the nitrogen metabolism and energy digestibility with Korean goats fed Acacia leaves. Korean J. Dairy Sci. 1, 35±44. LeHouerou, H.N., 1980. The role of browse in the Sahelian and Sudanian zones. In: LeHouero, H.N. (Ed.), Browse in Africa. ILCA, Addis Ababa, pp. 83±102. Mandibaya, W., Chihora, R.M., 1999. The nutritional value of Piliostigma thonninghii (Mutukutu, Monkey bread) pods as a feed supplement for communal cattle in Zimbabwe. Anim. Feed Sci. Technol. 78, 287±295. Norton, B.W., Rohan-Jones, W., Ball, F., Long, R.A., Murray, R.M., 1972. Nitrogen metabolism and digestibility studies with merino sheep given Acacia aneura and native pasture. Proc. Aust. Soc. Anim. Prod. 9, 346±349. Steel, R.G.D., Torrie, J.M., 1980. Principles and Procedures of Statistics, 2nd Edition. McGraw Hill, New York, pp. 36±48. Tanner, J.C., Reed, J.D., Owen, E., 1990. The nutritive value of fruits (pods with seeds) from four Acacia species compared with extracted noug (Guizotia absyssinica) meal as supplements to maize stover for Ethiopia highland sheep. Anim. Prod. 51, 127±133. Van Soest, P.J., Robertson, J.B., Lewis, B.A., 1991. Methods for dietary ®ber neutral detergent ®ber and non starch polysaccharides in relation to animal nutrition. J. Dairy Sci. 74, 3583±3597. Yahaya, M.S., Takahashi, J., Matsuoka, S., Kibon, A., 1999. Effect of supplementary feeding of cotton seed cake on feed intake, water consumption and work output of work bulls in Borno state, Nigeria. Anim. Feed Sci. Technol. 79, 137±143.