R.T. Fomunyam and S.E. Mbomi
Institute of Animal Research
Mankon, Bamenda
Cameroon
Abstract
Introduction
Materials and methods
Results
Discussion
Conclusion
References
Tephrosia spp., a legume grown locally in Cameroon, and cottonseed cake, a by-product obtained from processing of cotton were used to supplement maize and rice stalk diets fed to sheep and goats in the dry season. There were 6 diets fed to 12 Dwarf forest sheep and 12 West African Dwarf goats. A 2 x 6 factorial design was used for the analysis. This supplementation increased the efficiency of utilization of the crop residues by the ruminants. There was a higher intake, weight gain and low mortalities for sheep than goats. There were high mortalities for goats but those which survived had intake above maintenance level. Diets supplemented with 50% Tephrosia and 50% cottonseed cake had the best results in terms of intake, weight gain and percent mortalities.
Apparent digestibility values for crude protein was quite high and similar for all the diets. Therefore Tephrosia can equally be utilized like cottonseed cake for protein supplementation in adult sheep as no mortalities were observed.
Apparent dry-matter digestibility values were high for the control checks indicating better palatability and therefore high intake. More work should be done on this study to find out the appropriate levels and the combinations needed for protein supplementation using the above supplements so as to improve on the intake of agricultural by-products and to encourage the use of Tephrosia which can also be used for fuel and maintaining soil fertility.
A major constraint facing livestock development in Cameroon is the lack of adequate supplies of feedstuffs at economic prices. Feeds represent the greatest proportional cost in livestock production and its availability is affected by seasonal variation in feed quantity and quality which causes fluctuations in animal nutrition and productivity throughout the year.
There is competition between livestock and humans for the available protein feedstuffs.
Increasing land pressure and the resultant restriction of livestock to marginal lands has resulted in the need to supplement the animals that graze these lands. This problem is further aggravated by the rampant deforestation that is going on to divert lands to food crop production.
To increase animal production, recent stress has been on the utilization of agricultural by-products in animal feeding.
Despite the availability of these by-products in great quantities and their potentials as substantial feed sources, they are lowly utilised due to their low protein levels which makes them less palatable. This can however be overcome by supplementing the diets with locally produced cheap protein sources.
This paper considers the feeding of Tephrosia species, a cheap locally produced legume and cottonseed cake, a by-product from processing of cotton to overcome the constraint to the efficient utilization of rice and maize stalks fed to sheep and goats in the dry season when feed is in short supply.
Tephrosia species can also be used in alley cropping to improve soil fertility, prevent soil erosion and conserve moisture thereby increasing the yield of crops. At the end of the cropping season, Tephrosia leaves can be used for protein supplementation and the stalks for firewood. Propagation of Tephrosia species is by seeds which are abundant, therefore planting can easily be done by local farmers. Very little literature is known to the authors about the feeding of Tephrosia to small ruminants, although it is known to contain Rotenone, an insecticide and fish poison (National Academy of Science, 1979), In Cameroon, it is a big relish to cattle feeding; thus the study of its potentials as a protein supplement to small ruminant nutrition was necessary.
In the first trial 12 Dwarf forest and 12 West African Dwarf goats (average age 6 months) with an initial weight of 9.4 kg 10.2 kg were fed six diets namely :
1) 70% maize stover + 18% Tephrosia + 10% molasses + 2% bone meal2) 70% maize stover + 18% cottonseed cake + 10% molasses + 2% bone meal
3) 70% rice straw + 18% Tephrosia + 10% molasses + 2% bone meal
4) 70% rice straw + 18% cottonseed cake + 10% molasses + 2% bone meal
5) 70% maize stover + 9% cottonseed cake + 9% Tephrosia + 10% Molasses + 2% bone meal
6) 70% rice straw + 9% cottonseed cake + 9% Tephrosia + 10% molasses + 2% bone meal.
Maize and rice stalks were harvested 3 months post-harvest and hand-chopped into 3 cm pieces and stored in jute bags. Tephrosia species was also harvested and dried on black polythene sheets and also stored in jute bags. Molasses was added to maize stalks or rice straw and fed separately while protein supplement was fed twice at 8 am and 2 pm each day. All animals had free access to water and salt licks.
The design was a 6x2 factorial consisting of 6 diets and two species of animals. The following parameters were determined, weight gain, feed intake, and percent mortalities. The study was conducted for 5 months. Data collected was subjected to statistical analysis (Steel and Torrie, 1980).
In the second trial, 24 adult Dwarf forest sheep (average age 2 years) with a weight range of 16 kg - 35 kg were used to test the apparent digestibility of maize stover and rice straw diets supplemented with Tephrosia species and cottonseed cake. The plan of feeding was 10 days of adaptability and seven days of total collections. The animals were fed the following diets:
1) 70% maize stover + 28% Tephrosia + 2% bone meal2) 70% maize stover + 28% cottonseed cake + 2% bone meal
3) 70% rice straw + 28% Tephrosia + 2% bone meal
4) 70% rice straw + 28% cottonseed cake + 2% bone meal
5) 70% Pennisetum purpureum + 28% Tephrosia + bone meal
6) 70% Pennisetum purpureum + 28% cottonseed cake + 2% bone meal
7) 70% Tripsacum laxum + 28% Tephrosia + 2% bone meal
8) 70% Tripsacum laxum + 28% cottonseed cake + 2% bone meal
These animals also had access to water and salt licks.
Table 1 shows the chemical composition of feedstuffs used in these trials. Tripsacum laxum and Pennisetum purpureum were included as control checks.
Table 1. Percent chemical composition of feedstuffs used in test diets.
|
Feed items |
Characteristics |
||||
|
Dry matter |
Crude protein |
Crude fibre |
Ash |
Ether extract |
|
|
Maize stover |
91.1 |
5.3 |
33.1 |
7.1 |
2.1 |
|
Rice straw |
94.9 |
1.6 |
61.8 |
17.5 |
1.6 |
|
Tephrosia |
91.3 |
15.4 |
25.6 |
5.4 |
2.6 |
|
Cottonseed cake |
94.5 |
45.5 |
5.9 |
7.1 |
6.7 |
|
Elephant grass |
|||||
|
(Pennisetum purpureum) |
96.0 |
5.3 |
|
|
3.2 |
|
Guatemala grass |
|||||
|
(Tripsacum laxum) |
95.8 |
7.6 |
|
|
3.9 |
Table 2 shows that there was no significant (P<0.05) difference intake g/DM/day between animal species and between diets. However, values for goats averaged 404.3 g and for sheep 465 g. All animals fed rice straw and Tephrosia died between the second month and third month of the experiment while goats feeding maize stover and Tephrosia died during the second month of the experiment.
Table 2. Feed intake, weight gain and percent mortalities of sheep and goats fed rice and maize stalk/cottonseed cake and Tephrosia species.
|
Parameters |
Breeds |
Maize stover + Tephrozia |
Maize stover + Cottonseed cake |
+ Tephrozia |
Riche straw + Cottonseed |
Maize stover Tephrozia + Cottonseed cake |
Riche straw +Tephrozia +Cottonseed cake |
± SEM |
|
Feed intake g DM/animal |
Sheep |
379 |
498 |
286 |
570 |
528 |
529 |
|
|
Goat |
216 |
507 |
112 |
570 |
501 |
520 |
1.34 |
|
|
Daily weight gain g/animal |
Sheep |
47 |
43 |
14.3 |
40 |
43 |
47 |
|
|
Goat |
7.1 |
33 |
7.1 |
31 |
30 |
35 |
1.95 |
|
|
Sheep |
0 |
0 |
100 |
0 |
0 |
0 |
|
|
|
% mortality |
Goat |
100 |
50 |
100 |
0 |
50 |
0 |
|
Weight gain values varied between 33-35 g/day for goats and 40-47 g/day for sheep suggesting the levels fed were probably only adequate for maintenance.
Table 3 shows values for apparent digestibility. Values for crude protein were quite similar while those for dry-matter varied.
Feed intake for sheep and goats were in the range 3 3.7% of body weight indicating that the diets were palatable. Intake of dry-matter for goat meat should not exceed 3% of liveweight for any extended period of time (Devendra, 1980). However, the low weight gains showed poor efficiency of utilization which may be due to the use of stale maize stover ten months after it was harvested.
Table 3. Apparent digestibility (%) of the test diets fed to sheep.
|
Parameters |
Maize stover + Cottonseed cake |
Maize stover + Tephrosia purpurea |
Riche straw + Cottonseed cake |
Riche straw + Tephrosia purpurea |
Tripsacum laxum + Tephrozia purpurea |
Tripsacum laxum + Cottonseed cake |
Penisettum purpureum + Cottonseed cake |
Penisettum purpureum + Tephrosia purpurea |
|
Dry matter (%) |
51 |
54 |
60 |
59 |
85 |
85 |
84 |
80 |
|
Crude protein (%) |
74.1 |
67.0 |
63.3 |
56.3 |
63.8 |
59.8 |
72.3 |
72.5 |
Percent mortality showed that all goats fed maize stover and Tephrosia and all sheep and goats fed rice straw and Tephrosia died. The cause was not known. However, Tephrosia contains an insecticide Rotenone (National Academy of Science, 1979) which is a fish poison. This must have been toxic to the young growing animals which cannot tolerate the level present in their diets.
However, there were no mortalities when Tephrosia was fed to adult animals in the digestibility trials. Diets of maize stover or rice straw, supplemented with equal amounts of Tephrosia and cottonseed cake were the best diets with high intake, high weight gain and low mortalities.
For the apparent digestibility we found out that the crude protein utilization was quite high and similar for all the diets. There was a high dry-matter digestibility for Pennisetum purpureum and Tripsacum laxum than for maize and rice stalks. This might be due to better palatability and therefore high intake. Cottonseed cake did as well to supplement the by-products as Tephrosia. However, more mortalities were observed with young growing animals feeding Tephrosia.
Postmortem examination of dead animals showed that they died of either gastro-enteritis, pneumonia or starvation.
From the results, it appears that young growing sheep and goats can tolerate Tephrosia as a protein supplement only to a certain level which has to be studied by doing more work. However, adult sheep can tolerate Tephrosia as a protein supplement as no mortalities were observed. The most appropriate protein supplementation was a combination of 50% Tephrosia + 50% cottonseed cake together with the agricultural by-product (rice or maize stalks). This was able to maintain the animals with few mortalities. More work should be done on Tephrosia species as it has a lot of potential for both livestock and in the crop farming systems.
Tephrosia species and cottonseed cake can equally be used for protein supplementation as both have high and similar crude protein digestibility values. The major limitations to the use of rice and maize stalks in this study was low intake due to the diets not being palatable. This constraint can, however, be overcome by supplementing these diets as was done in this study using Tephrosia and cottonseed cake.
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