Growth and reproduction rates of West African Dwarf goats under high levels of feeding and management
Feed intake and weight gain of West African Dwarf goats
Goat management research at the University of Ife
P. HOFS, G MONTSMA AND S. NABUURS
Abstract
Introduction
Materials and methods
Results
Discussion
Reference
Since 1978 a flock of West African Dwarf goats has been kept largely indoors and fed grass hay ad libitum plus 30 to 60 g.kg-0.75.d-1 of a commercial concentrate. Routine observations and measurements of reproduction and weight gain have been made. Results are summarized and discussed using a productivity index. It is concluded that in this system the cumulative effect of 0.1 more kid per litter at birth, a kidding interval shortened by 20 days, 10 g more gain per day and a 0.1 kg higher birth weight would increase productivity of meat production (kg goat per year) by 28%. Separate effects of these changes were 5.5, 9.0, 11.1 and 1.4% increase in productivity respectively. The productivity of the flock to date is 21.0 kg of weaned goat per doe joined per year.
One of the research topics of the Department of Tropical Animal Production (the Netherlands) is the efficiency of meat production in West African Dwarf goats. The department has kept a flock of these goats since 1978, mainly for nutritional studies and to investigate climatic effects on production. Kids are raised at least once a year, and it is from this regular breeding cycle that routine data on reproduction and weight gain are recorded. Reproduction and growth rate are important factors in meat production, and the major parameters affecting these are litter size at birth and weaning, litter weight at birth and weaning, gestation length, and gain from birth to weaning.
The combination of these parameters leads to information on animal productivity in terms of meat production per doe per gestation, per year, or per lifetime.
A description of such productivity figures is given by Turner and Young (1969). With sheep data, they use a formula in which all components from mating of does to weaning of kids are taken into account. The result is a productivity index representing the number of kids weaned per doe from the original mating group. This figure gives useful information about how reproduction affects the yield of weaned offspring. In terms of meat production, we can expand Turner and Young's formula to give kilograms of goat produced per doe, per gestation, or per year, by multiplying their productivity figure by number of kiddings per doe per year and by liveweight of kids at weaning.
Sensitivity analysis is possible by varying the parameters in the formula in order to determine the effect of each parameter on total productivity.
Most dwarf goats in the Netherlands are kept exclusively as pets and were originally imported from West Africa, particularly from Cameroon. Our Department's experimental flock was purchased in 1978 in the Netherlands. Their conformation is still similar to the original West African Dwarf goat although mature weight and body measurements are up to 50% higher in some animals. (These differences are possibly due to some crossbreeding in the past and/or to better feeding). There is no evidence of a particular breeding season. In the past 5 years about 300 kiddings have taken place, and the reproduction data presented in this paper are based on these events.
Housing
The goats are kept mainly indoors in group pens with plywood walls and concrete floors bedded with wood scrapings. In these pens separate feeding cubicals are available, and are sometimes used to feed concentrates individually. Kidding takes place in individual pens, but does and kids are usually returned to the group pens within 1 or 2 days post partum.
Feeding
The flock is kept on a high plain of nutrition. All goats receive hay ad libitum. Pregnant and lactating does receive concentrates at a level of 60 g.kg-0.75.d-1 during the last month of pregnancy and in the suckling period. Kids have access to creep feeding, where rhoughage, concentrates and water are available ad libitum.
Breeding
Based on the requirements for experimental animals, controlled breeding of the flock is practiced. Mating of does takes place by admitting the buck three times daily to a group of animals to serve the does on heat. The number of matings per buck per day is restricted to three. If a second or third goat is on heat while the one that was served before is still willing, the second or third goat is served. In one breeding period the buck joined a group (group 005) of suckling does 10 days post partum. Here a marker was used to detect oestrus and/or matings. The use of markers was not very successful because of many misreadings, and because some does consumed them.
Measurements
The following data are routinely recorded: doe number, group, number of matings, buck number, expected kidding date, parity, litter size, litter weight, individual birth weight, weaning date, weaning weight of litter and individuals, litter size at weaning, liveweight (weekly), and particulars on kidding, gestation, suckling and disease.
Analysis of data
The productivity figure (Turner and Young, 1969) is estimated by the following formula:
(1)
where
= number of kids surviving to age Xi per doe joined;
= proportion of does which fail from stage Yp to Yp+1; between joining and kidding are q stages. (For example: 
= fail to come on heat; 
= fail to conceive; 
= lose embryos);
LBP = litter size per doe kidding; and
= survival rate of kids from age Xj to age Xj+1 .
Formula (1) may be shortened to:
(2)
where
EPJ = number of does kidding per doe joined;
= number of kids surviving to age Xi per kid born.
To arrive at the number of kg of weaned weight per doe per year, we have to combine 
with data on weight gain and parturition interval as follows:
(3)
where
MDY = weaned weight (kg per doe per year);
IBP = interval between parturitions (days);
WB = birth weight (kg);
AW = age at weaning (days); and
GD = gain per day (kg).
Mean values for the major reproductive and growth parameters are summarized in Table 1. These mean values may be useful to compare with data from literature, and as standards for future comparison, but they do not give direct information on productivity. Therefore, Table 2, which is based on 383 does, provides data on reproductive productivity (
). Litter size appears to show little variation. Conception rate and pregnancy rate are somewhat more variable, while kidding percentage and survival rate display relatively little variation. The resulting variation in reproductive productivity is very high, up to more than 100% .
Table 1. Major reproductive parameters and weight gain in West African Dwarf goats under intensive levels of management.
|
Parameter |
Number of observations |
Mean ± s.d. |
Range |
||
|
min. |
max. |
||||
|
Litter size |
|||||
|
|
at birth |
174 |
1.83 ± 0.61 |
1 |
4 |
|
|
at wearing |
168 |
1.66 ± 0.55 |
1 |
4 |
|
Litter weight (kg) |
|||||
|
|
at birth |
168 |
2.95 ± 0.88 |
0.82 |
5.40 |
|
|
at wearing |
139 |
13.73 ± 5.23 |
5.41 |
28.18 |
|
Gain, birth to weaning (g/day) |
139 |
139 ± 50 |
39 |
263 |
|
|
Age at weaning (days) |
147 |
80.2 ± 21.1 |
28 |
148 |
|
|
Gestation period (days) |
120 |
146.4 ± 2.3 |
141 |
152 |
|
|
Kidding interval (days) |
36 |
193 + 21 |
165 |
239 |
|
|
Birth weight (kg) |
308 |
1.61 ± 0.36 |
0.54 |
2.69 |
|
|
Weaning weight (kg) |
238 |
8.15 ± 2.48 |
2.76 |
16.40 |
|
|
Gain, birth to weaning (g/day) |
238 |
83 ± 19 |
25 |
148 |
|
In this paper we will restrict ourselves to the matter of meat productivity and the effects of the different parameters on this value.
The combination of formulas 2 and 3 gives:
(4)
If the mean values for these parameters are used (Tables 1 and 2), a productivity index of 21.0 kg of weaned weight per doe joined per year is indicated. This is based on the following data: EPJ = 0.81; LBP = 1.83; 
= 0.91; IBP = 193 days; WB = 1.6 kg; GD = 0.883 kg; Aw = 80 days.
A sensitivity analysis of the effects of various parameters on productivity is presented in Table 3. The proportional factors (EPJ, 
) will have a proportional effect on productivity. The results show the effect of a change in each parameter on overall productivity, and indicate that parameters strongly affected by the environment have the greatest impact on productivity expressed on the basis of weaned body weight.
Table 3. Percentage effects of various reproductive parameters on meat production (MDY)
|
Parameters |
Change |
Change in (MDY) (%) |
|
Litter size at birth (LBP) |
+ 0.1 kid |
+ 5.5 |
|
Kidding interval (IBP) |
- 20 days |
+ 11.6 |
|
Rate of gain (GD) |
+ 10 g.d-1 |
+ 9.7 |
|
Birth weight (WB) |
+ 0.1 kg |
+ 1.2 |
|
Total effect of above parameters |
|
30.5 |
This is reflected in the data in Table 2 and in the large standard deviations for these parameters given in Table 1. Environmental effects have a tendency to act cumulatively, and in the present example would affect an increase or decrease in productivity of approximately 30%.
In some mating groups, low productivity has only one major cause. In group 006 (Table 2), for example, low pregnancy rate is the major factor affecting productivity, although reasons for this low pregnancy rate are unclear. Groups 009 and 010 were subgroups which were moved to another farm, where housing was less favourable and supervision less strict. In group 009, which kidded during winter, this change was reflected in a high mortality. In group 010, which kidded during summer, a large number of abortions occurred. Here too, the reasons are not clear. A preliminary estimate of productivity in these two groups is approximately 12 kg of weaned weight per year, which is little more than 50% of the average value. Thus it appears that careful feeding, housing and especially management are important prerequisites for high productivity. This is likely to be even more important if genetic traits are improved.
Turner H N and Young S S Y. 1969. Quantitative genetics in sheep breeding. Macmillan of Australia.
G. ZEMMELINK, B.J. TOLKAMP and J.H. MEINDERTS
Abstract
Introduction
Materials and methods
Results
Discussion
References
Two experiments with a total of 46 animals were carried out to measure feed intake and weight gain of West African Dwarf goats when fed ad libitum hay (Treatment A) or ad libitum hay plus varying amounts of concentrates: 30 g.kg-0.75.d-1 (B), 60 g.kg-0.75.d-1 (C) and ad libitum (D). Mean intake of organic matter (OM) from concentrates was 0, 23.6, 46.2 and 64.7g.kg-0 75.d-1 for treatments A to D respectively, and intake of OM from hay was 49.7, 30.3, 15.3 and 6.7g kg-0 75.d-1. Total intake of organic matter, expressed as % of body weight, was 2.7, 2.8, 3.2 and 3. 7, and mean daily weight gain per treatment was 16, 35, 58 and 87g.d-1 respectively. Intake of digestible organic matter y (g.d-1) was related to metabolic weight x1 (kg0.75), and to weight gain x2 (g.d-1), as follows: y = 26.0 x1 + 2.41x2. These preliminary results suggest that the NRC* estimates for maintenance requirements of pen-fed goats are correct, but that energy requirements for gain are 25% higher than is suggested in the feed requirement tables of the NRC. It is suggested that goats should not be looked upon as animals which are less demanding in terms of feed quality than sheep.
[* National Research Council (USA).]
Feed intake and weight gain are important parameters in determining the efficiency of animal production. Many data are available for cattle, pigs, sheep and poultry. However, information on goats, especially meat goats, is scarce with regard to these parameters. Because of the importance of meat goats as farm livestock in the humid tropics of West Africa, the Department of Tropical Animal Production of the Agricultural University in Wageningen, the Netherlands, cooperates with the University of Ife, Nigeria, in a research programme on West African Dwarf goats.
This paper summarizes the results of two feeding trials with West African Dwarf goats in Wageningen. The primary objective of these experiments was to measure feed intake and weight gain of goats fed on hay, or hay plus various levels of concentrates.
In both experiments, 24 castrated West African Dwarf goats (average age 6 months) that had received ad libitum hay plus a limited amount of concentrates (45 g.kg-075.d-1) since weaning, were divided into four treatment groups of six animals each. The first group (A) received ad libitum hay only; the other three received ad libitum hay plus varying levels of concentrates: 30 g.kg-0 75.d-1 (B), 60 g.kg-0.75.d-1 (C) and ad libitum (D). The composition of these feeds is summarized in Table 1.
Table 1. Composition of feeds as % of dry matter.
|
Feed experiment |
Hay |
Concentratea |
||
|
I |
II |
I |
II |
|
|
Organic matter |
89.6 |
88.8 |
90.7 |
90.8 |
|
Crude protein |
13.2 |
16.1 |
18.4 |
18.4 |
|
Ether extract |
- |
- |
1.8 |
2.5 |
a Cassava meal (30%), soybean meal (25%), maize (15%), maize gluten feed (10.2%), alfalfa meal (10%), molasses (7%), lime (1.5%), salt (0.8%), mineral mix (0.5%).
All animals had free access to water and salt licks. Throughout the experimental periods, 56 days in Experiment I and 59 days in Experiment II, the animals were housed in individual metabolism cages with screen floors, which allowed separate collection of faeces and urine. The animals were accustomed to this kind of housing, as well as to the experimental rations, at least 1 week before the beginning of each experimental period. Hay was offered in the morning and in the afternoon in amounts to provide an excess of at least 25%. Concentrates were offered in the morning. Refused feed was removed before the morning feeding. Intake and digestion of feed were measured in both experiments during two 1 week periods: days 12-19 and 47-54 in Experiment I, and days 14-21 and 39-46 in Experiment II. Liveweight (W) of the animals was measured once a week before the morning feeding, except during those weeks when intake and digestibility were measured. The amount of concentrates offered to animals on Treatments B and C was adjusted every 2 weeks according to the last liveweights. Liveweight gain (G) was estimated by linear regression of W in time.
Data on feed intake and weight gain are summarized in Table 2. Data for two animals in Experiment I (one on Treatment C and one on Treatment D) were incomplete and are therefore not included in the analysis. For most parameters no significant differences between the mean values of the two experiments were found. Significant differences between parameters in the two experiments are indicated in the table.
All animals in Treatments B and C consumed the total amount of concentrates offered; i.e. amounts equivalent to 23.6 and 46.2 g OM.kg-0 75.d-1 respectively. Ad libitum intake of concentrates in Treatment D averaged 64.7 g OM.kg-0 .75.d-1 or 71.3 g dry matter, with a coefficient of variation of 14.3%. Intake of organic matter from hay decreased sharply with increasing intake of concentrates. This decreased intake of hay as a result of concentrate consumption in Treatments B, C and D, as compared with Treatment A, represents replacement ratios of 0.82, 0.74 and 0.66 g of hay per g of concentrates. Thus, the largest decrease in hay consumption occurred at the lower level of concentrate intake. Animals that received ad libitum concentrates ate very little hay. For these animals hay constituted on the average only 9.4% of total intake. For two individual animals, hay intake was less than 5% of total intake. Notwithstanding this high level of concentrate intake, no digestive disorders were observed.
Table 2. Feed intake and weight gain of West African Dwarf goats on ad libitum hay plus varying levels of concentrates (± SD).
|
Treatment |
A |
B |
C |
D |
|
|
No. of animals |
12 |
12 |
11 |
11 |
|
|
Amount of concentrates offered (g fresh weight.kg-0.75.d-1) |
- |
30 |
60 |
ad lib. |
|
|
Initial weight (kg) |
11.5 ± 1.5 |
12.0 ± 2.1 |
11.5 ± 1.8 |
12.1 ± 2.5 |
|
|
Final weight (kg) |
12.5 ± 1.8 |
14.0 ± 2.0 |
15.0 ± 1.9 |
17.0 ± 2.0 |
|
|
Intake of organic matter: |
|||||
|
|
concentrates (g.kg-0.75.d-1) |
- |
23.6 ± 0.3 |
46.2 ± 0.5 |
64.7 ± 9.2 |
|
|
hay (g.kg-0.75.d-1) |
49.7 ± 6.7 |
30.3 ± 5.2 |
15.3 ± 7.4a |
6.7 ± 2.2 |
|
|
total (g.kg-0.75.d-1) |
49.7 ± 6.7 |
53.9 ± 5.1 |
61.5 ± 7.2b |
71.4 ± 10.8 |
|
|
total (g.kg-0.75.d-1) |
26.7 ± 3.5 |
28.4 ± 3.1 |
32.1 ± 3.2c |
36.6 ± 6.9 |
|
Intake of digestible organic matter (g.kg-0.75.d-1) |
30.5 ± 3.8 |
37.5 ± 3.7 |
46.6 ± 3.6 |
55.9 ± 8.5 |
|
|
Weight gain (g.d-1) |
15.8 ± 6.8 |
35.1 ± 8.5 |
58.5 ± 11.1 |
87.0 ± 21.2 |
|
|
Ratio, intake of organic matter from concentrates/weight gain |
- |
4.9 ± 1.4 |
5.7 ± 1.2 |
5.8 ± 1.1 |
|
a Exp. I: 21.1 ± 4.7; Exp. II: 10.5 ± 5.6
b Exp. I: 67.3 ± 4.5; Exp. II: 56.7 ± 5.3
c Exp. I: 34.5 ± 2.1; Exp. II: 30.1 ± 2.5
Apparent digestibility of consumed organic matter (d, in %) was closely related to the fraction of concentrates (fc, in %) in the consumed feed:
Exp. I: d = 59.2 + 0.182 fc (RSD = 2.0)
Exp. II: d = 63.7 + 0.190 fc (RSD = 1.2).
Thus, at the same concentrate/hay ratio, digestibility was about 5 percentage units higher in the second experiment than in the first, and in both cases digestibility of concentrates was nearly 20 percentage units higher than digestibility of hay. As a result, intake of digestible organic matter (DOM) was 1.83 times higher on Treatment D than on Treatment A, whereas intake of total OM was only 1.44 times higher.
Animals on the all-hay ration gained 16 g.d-1, which is only 18% of the daily weight gain of animals on hay plus ad libitum concentrates. The amount of concentrates consumed per gram liveweight gain varied considerably between individual animals. The mean values for Treatments C and D (5.7 and 5.8 g concentrate OM per g of gain) suggest, however, that the return from concentrates does not diminish when this is offered ad libitum compared to a level equal to about 70% of ad libitum (Treatment C).
Mean liveweight gain per treatment was linearly related to intake of DOM. The estimate of energy requirements for maintenance and gain resulted in the equation:
(RSD = 28.4, df = 44)
where
IDOM = intake of DOM in g.d-1;
Wm = mean liveweight during the experimental period; and
G = liveweight gain in g.d-1.
Transformation of DOM into kJ ME (using the same conversion factors as NRC, 1981) yields the estimates of 410 ± 19.2 kJ ME.kg-0.75.d-1 for maintenance and 38.0 ± 2.40 kJ ME per gram liveweight gain.
Feed intake varies with weight, physiological status and breed. Although much-higher intakes have been recorded for dairy goats, it is widely assumed that for meat goats intake of dry matter will not exceed 3% of liveweight for any extended period of time (Devendra, 1980; Morand-Fehr, 1981). Mba et al (1975) reported intakes by Red Sokoto goats of up to 9% of body weight, but this figure is incompatible with the rest of their data and may be the result of errors. In our experiments, dry matter intake of animals on hay only averaged 3% of body weight. On Treatment D (ad libitum concentrates) intake increased to 4%. Naude and Hofmeyer (1981) found a value higher than 3% in Boergoat kids. Apparently dry matter intake of meat goats can be higher than 3% of body weight if good quality feed is offered. It should, however, be realized that expressing feed intake as a percentage of body weight leads to inflated figures when it concerns small animals such as dwarf goats. For comparisons with other animals, it is more meaningful to express intake per unit metabolic weight (W0.75). When expressed in this way, the feed intake of West African Dwarf goats, as measured in our experiments, can by no means be considered exceptionally high. Dry matter intake of animals receiving only hay averaged 56 g.kg-0 75.d-1 and intake of digestible organic matter averaged just over 30 g.kg-0.75.d-1. Thus, when offered ad libitum hay with a digestibility of 60% and 13 to 16% CP, West African Dwarf goats ate only 17% more than their maintenance requirements. This confirms our experience with much larger numbers of animals in the flock indicating that West African Dwarf goats do not perform well on hay alone, even if this is of good quality. For these animals to perform adequately, hay needs to be supplemented with concentrates. As our results show, intake of hay then decreases. Maximum gains are only obtained with high levels of concentrates which almost entirely replace the intake of hay. The average intake of digestible organic matter of animals on ad libitum concentrates (55.9 g.kg-0.75.d-1 ) was equivalent to 2.15 times the estimated maintenance requirements, and similar to the maximum intake of energy by growing sheep and cattle.
Reliable data on growth rates of West African Dwarf goats are scarce. Data on growth rates of West African Dwarf goats in Ghana were presented by Sada and Vohradsky (1973), and Adebowale and Ademosun (1981) presented data on growth rates of Nigerian West African Dwarf goats. Wilson (1958) published data on East African Dwarf goats in Uganda. In several cases, the levels of feeding described in these papers are not clear. The reported weight gains, even when the plane of nutrition is described as high or improved, are in most cases lower than the maximum group average of our experiments. In particular it is noted that Adebowale and Ademosun measured a weight gain of only 30 to 50 g.d-1 in animals that received ad libitum concentrates. Wilson's data on East African Dwarf goats showed maximum gains of 85 to 100 g.d-1, which is about the same as was found in our experiments. Much higher weight gains of West African Dwarf goats, 400 g.d-1 or more, were reported by Akinsoyinu et al (1975; 1976) and Oyenuga and Akinsoyinu (1976). It would appear, however, that these data are unrealistic: if such gains could be achieved, West African Dwarf goats would reach their mature weight in a few months' time.
Estimates of the energy requirements for maintenance of goats have recently been reviewed by Devendra (1980), Sengar (1980), Morand-Fehr (1981) and NRC (1981). There is considerable variation in the reported estimates. The differences may partly be explained by the fact that some of the quoted values refer to lactating dairy goats while other values refer to meat goats. However, in some cases, different reviewers derived different figures from the same original papers.
Besides simple misquoting, this may reflect confusion as to the way in which values were obtained. Several of the original estimates are based on experiments of questionable design, with very small numbers of animals and/or questionable analyses of the data. Our estimate of 410 kJ ME.kg-0 75.d-1 for pen-fed West African Dwarf goats is close to the value of 424 kJ which is used for pen-fed goats by NRC (1981).
While Mohammed and Owen (1980) concluded that the maintenance requirements of castrated goats are substantially greater than those of wether sheep, it would appear from our results that the maintenance requirements of pen-fed goats are not lower than those of sheep. As is pointed out by NRC (1981), the maintenance requirements of goats may be considerably higher when the animals are allowed more freedom of movement. In addition to this, our data suggest that the quoted value may only be valid for animals with a high weight of gut fill, as occurs when animals are fed on all-roughage rations. Animals on high levels of concentrates may have a much lower gut fill or a higher empty body weight and, consequently, a higher maintenance requirement when this is expressed on the basis of full body weight.
The estimate of requirements for gain, as used by NRC (30.3 kJ ME per g of gain), is based on three original values from the literature: 42.6, 21.5 and 26.9 kJ. These data differ so much from one another that taking a simple mean must be considered a doubtful basis for formulating feeding standards for goats. The first value is based on work with only six goats by Devendra (1967). Moreover, the figure quoted by NRC (1981) is the one which followed from the first step in the analysis of the data and this value should not, according to Devendra himself, be taken as the appropriate estimate. Whether the other estimates used as a basis for the NRC standards are any more accurate is unclear to us because the original papers could not be obtained.
Our present estimate of the requirements for gain (38.0 kJ ME per g of gain) is 25% higher than the value assigned by NRC (1981). In addition, our estimate would be still higher (44.4 kJ ME per g of gain) if G instead of IDOM were chosen as the dependent variable in the regression equation. There is considerable disagreement in literature as to which procedure should be followed (e.g. ARC, 1980). The value of 30.8 kJ ME per g of gain does not differ markedly from values obtained by similar procedures of analysis for growing sheep. According to NRC (1975), sheep of 30 to 50 kg liveweight require 33 to 48 kJ ME per g of gain.
Goats are sometimes described as exceptionally capable of digesting and utilizing poor-quality feeds, and as having low requirements for maintenance and production. The former part of this suggestion may originate in the fact that farmers in Europe were advised in the past that kitchen offal could be fed to goats. Kitchen 'offal' is, however, not equivalent to low-quality feed; on the contrary, in terms of ruminant nutrition, it may be of very high quality. Utilizing this material for goats was one way of meeting a demand for a variety of feeds, which is a well established characteristic of goats. Louca et al (1982) concluded that goats derive their advantage from an ability to consume vegetation types not normally eaten by other ruminants, and from a higher digestive efficiency for poor-quality roughages. Van Soest (1982), however, suggested that the conclusion that goats digest feed better than sheep and cattle is merely the result of the goats' sharper selection from the material offered.
The first priority for programmes designed to improve goat production is to understand properly the requirements of these animals. Critical experiments, rather than superficial observations tending to confirm existing ideas, are badly needed. Of course, in developing countries, it may not be acceptable to base goat production on ad libitum concentrate feeding. The challenge then is to investigate which other feeds can be used to meet the requirements of goats. The great experience of the traditional goat farmer is likely to be the best starting point.
ARC (Agricultural Research Council). 1980. The nutrient requirements of ruminant livestock. Commonwealth Agricultural Bureaux, Farnham Royal Gresham Press, Surrey.
Adebowale E A and Ademosun A A. 1981. The carcass characteristics and chemical composition of the organs and muscles of sheep and goats fed brewers' dried grains. Trop. Anim. Prod. 6: 133-137.
Akinsoyinu A O. Mba A U and Olubajo F O. 1975. Studies on energy and protein utilization for pregnancy and lactation by the West African Dwarf goats in Nigeria. East Afr. Agric. For. J. 41: 167- 176.
Akinsoyinu A O. Mba A U and Olubajo F O. 1976. Crude protein requirement of West African Dwarf goats for maintenance and gain. J. Assoc. Advanc. Agric. Sci. Afr. 3: 75-80.
Devendra C. 1967. Studies in the nutrition of the indigenous goat of Malaya, III. The requirement for liveweight gain. Malays. Agric. J. 46: 98-118.
Devendra C. 1980. Feeding and nutrition of goats. In: Church D (ed.) Digestive physiology and nutrition of ruminants. Oregon State University, Corvallis.
Louca A, Antoniou T and Hatzipanayiotou M. 1982. Comparative digestibility of feedstuffs by various ruminants, specifically goats. In: Proceedings of the 3rd international conference on goat production and disease. Tucson, Arizona. pp. 122-132.
Mba A U. Egbuiwe C P and Oyenuga V A. 1975. Nitrogen balance studies with Red Sokoto (Maradi) goats for the minimum protein requirements. East Afr. Agric. For. J. 40: 285-291.
Mohammed H H and Owen E. 1980. Comparison of the maintenance energy requirement of sheep and goats. Anim. Prod. 30:479.
Morand-Fehr P. 1981. Nutrition and feeding of goats. In: Gall C (ed.) Goat production. Academic Press, London.
NRC (National Research Council). 1975. Nutrient requirements of sheep. National Academy of Sciences, Washington D.C.
NRC. 1981. Nutrient requirements of goats. National Academy Press, Washington D.C.
Naude R T and Hotmeyer H S. 1981. Meat production. In: Gall C (ed.) Goat production. Academic Press, London.
Oyenuga V A and Akinsoyinu A O. 1976. Nutrient requirements of sheep and goats of tropical breeds. In: Proceedings of the 1st international symposium on feed composition, animal nutrient requirements and computerization of diets. Utah.
Sada I and Vohradsky F. 1973. West African Dwarf goat in Ghana, 11. Growth rate and selection criteria. Institute of Tropical and Subtropical Agriculture, Agricultural University, Prague.
Sengar O P S. 1980. Indian research on protein and energy requirements of goats. J. Dairy Sci. 63: 1655-1670.
Van Soest P J. 1982. Nutritional ecology of the ruminant. O and B Books, Corvallis, Oregon.
Wilson P N. 1958. The effect of plane of nutrition on the growth and development of the East African Dwarf goat, I. Effect of plane of nutrition on the liveweight gains and the external measurements of kids, J. Agric. Sci. (Cambridge) 50: 198-209.
A.A. ADEMOSUN, H.J. JANSEN and V. van HOUTERT
Abstract
Introduction
Feeding studies
Management and housing
References
To date, results of research on the management of West African Dwarf goats show that intake of dry matter and digestible dry matter from grasses such as Cynodon nlemfuensis and Panicum maximum are too low to sustain reasonable levels of production. Substantial improvements in feed intake and digestibility can be achieved by feeding legumes such as Gliricidia sepium and Leucaena leucocephala, although additional research is needed on the optimum levels at which these legumes can be fed.
Early livestock development programmes in Nigeria emphasized cattle improvement, particularly through disease control. Dwarf sheep and goats have been neglected in livestock development programmes, principally because they were regarded as poor feed converters, slow growers, and animals destined to roam the countryside, subsisting on kitchen wastes and bush grazing. However, these small animals have a definite advantage over other breeds in that they are adapted to the environment of the humid zone: they continue to make substantial contributions to meat consumption; they are particularly favoured for festivals in certain parts of Nigeria; and their meat can be handled easily by small families and communities in the absence of refrigeration.
Investigations were initiated with dwarf sheep and goats at the University of Ife in the late 1960s, when these animals were used mainly in forage evaluation studies. It was soon realized that external assistance and collaboration with other bodies would be required, and in 1978 an approach was made to the Small Ruminant Programme of the International Livestock Centre for Africa (ILCA). This led to negotiations with the Agricultural University at Wageningen, the Netherlands, and ultimately to the present project located at the University of Ife. The broad objectives of the project are:
1. To study the management and economics of production of West African Dwarf goats in the humid tropics;2. To develop research facilities;
3. To disseminate research results;
4. To train scientists.
The project started in September 1981 and currently has a flock of about 90 goats.
From the beginning it was felt that any improved goat production system in the humid zone of Nigeria would have to be based on locally available fodder resources. Therefore, the main research effort was directed to the assessment of the nutritive value of these forages. In the first experiment, the effect of selective consumption of poor-quality, dry-season Star grass hay (Cynodon nlemfuensis) on feed intake and digestibility was measured. The dry matter intake appeared to be very low, ranging from 32 to 40 g per kg metabolic weight (W0.75). When more hay was offered, a more leafy diet was selected from the hay. This led to an increase in voluntary intake, higher digestibility, and higher crude protein content in the selected feed compared to the feed on offer (Table 1). There appeared to be a close positive relationship between the percentage excess feed and the amount of leaf in the selected diet (Figure 1). These results further illustrate the selective eating habit of goats; in this example, the most nutritious feed component was consumed first.
Table 1. Effect of level of Star grass hay (Cynodon nlemfuensis) offered to West African Dwarf goats on voluntary intake, selective consumption and digestibility.
|
Number |
DM offered (g.kg-0.75.d-1) |
% leaf in hay offered |
% leaf in selected diet |
DM intake |
Digestibility % |
DM intake |
% CP in hay offered |
% CP in selected diet |
|
3 |
44 |
43.2 |
54.5 |
32.3 |
40.1 |
13.0 |
4.3 |
4.8 |
|
3 |
88 |
43.2 |
75.2 |
40.6 |
43.2 |
17.5 |
4.3 |
5.7 |
|
3 |
131 |
43.2 |
86.7 |
39.9 |
46.4 |
18.5 |
4.3 |
6.2 |
Guinea grass (Panicum maximum) was used in several feeding trials. Its nutritive value was evaluated when the grass was either young and nutritious, or when it was dry-season standing hay. Dry matter intake (DMI) varied from 54.9 g.kg-0.75.d-1 with young, well fertilized grass, to 43.1 g.kg-0.75.d-1 with standing hay (Table 2).
Figure 1. Selectivity of WAD goats fed on Star grass hay (Cynodon nlemfuensis) as influenced by the level of feeding.
Table 2. Effect of age of regrowth on nutritive value of Panicum maximum offered ad libitum to West African Dwarf goats.
|
Age of regrowth (days) |
DM intake |
Digestibility |
DDM intake |
|
30a |
54.9 |
73.8 |
40.6 |
|
60b |
48.3 |
47.5 |
22.9 |
|
90b |
43.1 |
46.0 |
19.8 |
a Four animals; grass fertilized with 100 kg NPK/ha (15-15-15; NPK).
b Six animals; grass not fertilized.
These data suggest that the DMI from Panicum is sufficient to achieve satisfactory production levels only when the grass is relatively immature.
During the 1982/83 dry season two experiments were conducted in which Gliricidia sepium and Leucaena leucocephala were used as supplementary feed in combination with Panicum hay. With Gliricidia intake in the range of 10.8 to 31.8 g.kg-0 75.d-1, the DMI of Panicum was only slightly reduced as more Gliricidia was consumed (Table 3). The digestibility of the consumed feed improved through feeding more Gliricidia, and hence the effect of supplementation on digestible dry matter intake (DDMI) was even more pronounced.
Table 3. Effect of feeding various levels of Gliricidia sepium with Panicum maximum on voluntary intake and digestibilitya.
|
DM intake |
Digestibility |
DDM intake |
||
|
Gliricidia |
Panicum |
Total |
||
|
0 |
43.1 |
43.1 |
46.0 |
19.8 |
|
10.8 |
39.8 |
50.6 |
47.7 |
24.5 |
|
21.3 |
38.1 |
59.4 |
51.1 |
30.3 |
|
31.8 |
37.2 |
69.0 |
54.9 |
37.9 |
a Six animals/feeding level; DM intake of Gliricidia represents complete consumption of Gliricidia offered.
The results of a similar feeding trial using Leucaena leucocephala as the legume supplement are given in Table 4. This experiment was conducted in two phases. First, approximately 10 and 30 g of Leucaena DM per kg metabolic weight were fed. Afterwards, the animals previously on 30 g of Leucaena were put on 20 g of Leucaena DM per kg metabolic weight, and those previously on 10 g of Leucaena were not fed Leucaena but were fed only the basal Panicum hay. The results are in line with those of the previous trial, except that there appeared to be a marked improvement in both voluntary intake and digestibility over time.
Table 4. Effect of feeding various levels of Leucaena leucocephala with Panicum maximum on voluntary intake and digestibilitya.
|
Period |
DM intake (g kg-0.75.d-1) |
Digestibility (%) |
DDM intake |
||
|
Leucaena |
Panicum |
Total |
|||
|
1 |
10.7 |
39.6 |
50.3 |
39.8 |
20.0 |
|
1 |
31.6 |
36.8 |
68.4 |
47.8 |
32.6 |
|
2 |
0 |
48.3 |
48.3 |
47.5 |
47.5 |
|
2 |
20.6 |
45.5 |
66.1 |
52.1 |
34.4 |
a Six animals/feeding level; DM intake of Leucaena represents complete consumption of Leucaena offered.
In experiments with either Gliricidia or Leucaena the improvement in digestibility, dry matter intake and digestible dry matter was linearly related to the amount of legume fed. These results suggest that even higher intake and digestibility might be achieved with higher legume levels, including an 'all-legume' treatment.
Similar results have been recorded by Zemmelink et al (1984) with West African Dwarf goats in the Netherlands. The feeding of increasing levels of concentrates with a basal diet of ad libitum hay resulted in a decreasing intake of hay but increasing total organic matter intake (OMI) and increasing growth rates.
Cynodon and Panicum are two grasses commonly evaluated as livestock feeds in southwestern Nigeria. The levels of intake recorded with these grasses are so low that they cannot be expected to sustain reasonable levels of production in goats. The data in Tables 3 and 4 on feeding of Panicum hay showed a DDMI of only about 20 g.kg-0.75.d-1. Lower intake figures were recorded with Cynodon (Table 1). In experiments where hay was fed to West African Dwarf goats in the Netherlands, an OMI of about 50 g.kg-0.75.d-1 was recorded. This resulted in growth rates of about 16 g.d-1 (Zemmelink et al, 1984). This is considerably higher than the intake levels recorded here.
In June 1983, a first group of eleven young male goats became available for experimental purposes. In order to assess their growth potential, these animals were put on a long-term growth trial. Six animals were fed ad libitum concentrate and fresh Guinea grass, while five animals were fed the same fresh Guinea grass plus fresh Leucaena leaf at the level of 50 g DM.kg-0.75.d-1. Animals were permanently housed in metabolic cages, and feed intake and digestibility were measured at regular intervals.
Although the experiment is still in progress, the growth data over the first 100 days are shown in Figure 2. The animals in both groups needed an adaptation period of approximately 40 days before they started gaining weight. Over the next 60 days, the animals receiving concentrate grew at a rate of 59.5 g.d-1, while the animals receiving Leucaena grew at 43.3 g.d-1.
Figure 2. Liveweight gains of young male WAD goats when fed fresh Panicum maximum and ad lib concentrate or ad lib fresh Leucaena leaf.
These growth data are similar to other results recorded in the humid zone (Ademosun, 1973; Adebowale and Ademosun, 1981). However, they are lower than those recorded for the same breed of goats in the Netherlands (Hofs et al, 1984).
During the first year of the project newly purchased goats were kept under grazing. Cynodon nlemfuensis was the main roughage fed, and later Panicum maximum was offered in restricted amounts. A concentrate mixture of whole maize (50%), rice bran (30%), brewers' dried grains (10%), groundnut cake (7.5%), and minerals and salt (2.5 %), was provided at a rate of 200 g.d-1 for dry animals and 500 g.d-1 for lactating animals. Even with this substantial supplement, it was extremely difficult to maintain body condition and herd health. Both ecto- and endoparasitic infestations required expensive treatment. Voluntary grazing time was limited, and mortality of offspring was extremely high.
Consequently, in September 1982 the flock was confined, and cut-and-carry feeding was substituted for grazing. The main forages used were Panicum maximum, Gliricidia sepium and Leucaena leucocephala. Concentrate supplement, as indicated above, was still provided individually for adults and growers, whereas creep feeders were used to provide concentrate and forages to suckling kids. The use of bamboo as a low-cost building material was tested by constructing slatted floors expected to improve hygienic conditions (especially for kids), facilitate collection of faeces for application to farm land and to eliminate cleaning of pens.
Based on the experience gained from constructing the bamboo floors, a low-cost goat shed with a wooden frame and bamboo-slatted floors, walls and partitions, was designed and constructed. Galvanized corrugated sheets were used for roofing. The shed provides space for 10 to 12 adult females, a breeding buck, and all offspring up to slaughter weight. The cost of the building materials in 1983 was US$ 364. This house will be used to test the profitability of goat keeping under the management system outlined above.
The management package incorporates health care, feed supply and housing. Feed will be supplied mainly from browse plants such as Gliricidia and Leucaena, from household wastes, and from industrial byproducts such as brewers' grains. Future research will revolve around improvements in health, feeding and housing. It is expected that farmers will be identified who will participate in pilot projects in Oyo and Ondo States. This will involve a team of animal scientists, agronomists and extension specialists. It is hoped that this project will make a significant impact on goat production in southwest Nigeria.
Adebowale E A and Ademosun A A. 1981. The carcass characteristics and chemical composition of the organs and muscles of sheep and goats fed brewers' dried grain-based rations. Trop Anim. Prod. 6: 122-37.
Ademosun A A. 1973. The development of the livestock industry in Nigeria - Ruminants. Proc. Agric. Soc. Niger. 10:13-20.
Hofs P. Montsma G and Nabuurs S. 1985. Growth and reproduction rates of West African Dwarf goats under high levels of feeding and management. In: Sumberg J E and Cassaday K A (eds) Sheep and goats in humid West Africa. Proceedings of the workshop on Small Ruminant Production Systems in the Humid Zone of West Africa, held in Ibadan, Nigeria, 23-26 January 1984. ILCA, Addis Ababa. pp. 25-28.
Zemmelink G. Tolkamp B J and Meinderts J H. 1984. Feed intake and weight gain of West African Dwarf goats. In: Sumberg J E and Cassaday K (eds) Sheep and goats in humid West Africa. Proceedings of the workshop on Small Ruminant Production Systems in the Humid Zone of West Africa, held in Ibadan, Nigeria, 23-26 January 1984. ILCA, Addis Ababa. pp. 29-33.
= number of weaning kids per doe joined) per mating group.