The contribution of browse to cattle fodder in the sedentary system of the Office du Niger**

Maimouna Salah Dicko-Touré

Head of the Nutrition Section, ILCA/Mali project: Sahel programme

1. Introduction

2. Description of the environment

3. Methodology of behaviour research

4. Results and discussions

4.1 Animal behaviour

4.2 The proportion of grazing time spent on browse

4.3 Estimates of browse ingestion

Biblography

1. Introduction

Before attempting to evaluate possible future improvements to the nutritional level of a herd, it is essential to have detailed knowledge of the previous nutritional conditions of the animals in question.

As regards the traditional cattle production systems in Mali, this nutritional level can be taken as equal to the nutritive value of the pastures¹ which exist between environment, management and nutrition make it necessary to take these various factors into account in any nutritional research.

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(^l) The nutritive value of a pasture is defined as the product of the quantity times the energy value of the forage actually consumed.

In the course of research on a herd raised under the traditional sedentary system of the Office du Niger, we register certain data which fall into these categories every month, over a period of five consecutive days: the quantity and quality of fodder actually ingested, the productivity of the pastures, the herd management methods, and the behaviour and performance of the animals. The results should enable us to better identify and evaluate any future programmes which may be undertaken to improve the production of these animals.

Within the framework of this research, the amount of time the cattle spend each day on the different types of fodder present on the pastures has been worked out. In this paper, which is concerned mainly with this aspect of the subject, the position which browse occupies in the daily diet during the various bioclimatic periods will be discussed.

2. Description of the environment

The Office du Niger, an organization for the development and utilization of irrigated crops in the dead delta of the Niger River in Mali, covers a zone of 45,000 hectares of irrigated land, primarily devoted to rice cropping. A large part of the profits derived from this activity by the cultivators—called colons —is invested in the form of animals (sheep, goats and cattle). These animals, apart from a small number which remain in the village (sheep and goats for fattening at home, milk cows and cattle used for ploughing) are entrusted to Fulani herdsmen who rent out their services for a monthly salary of two thousand Malian francs (2,000 FM = US$5) plus all the milk produced by the herds entrusted to them.

Taken as a whole, these herds form the basis of an animal production system which is semi-sedentary rather than sedentary (their official category), within an area of influence covering a radius of some thirty kilometres around the irrigated perimeter. From the natural pastures where they remain from July to October, they move to the millet fields and fallows in November, then to the rice fields from January to April, and subsequently return to the millet fields and fallows which provide a holding area until the beginning of the 'winter cycle' in July. One of these herds, composed of 85 head of cattle, was used for testing.

The research work is carried out around Niono, situated in the Sudano-Sahelian zone with an average rainfall of 550 mm, which is the economic centre of the Office du Niger.

The fodder availabilities noted in Table 2 in kg of DM ha have been calculated by the ecological team of the ILCA project for various pastures: on grass (natural pastures), millet stubble and straw (millet fields and fallows), and rice straw and shoots (rice fields). The estimates are, however, very approximate, since they concern rangeland which was neither delimited nor subject to any form of control.

The fodder contribution of browse has not been evaluated. However the browse species used by cattle and their relative importance according to the pasturages are shown in Table 1.

Table 1 Palatable browse species: some characteristics and relative proportions on different types of pasture

^aThe periods shown are not applicable for rice plots and their surrounds, for which the vegetation phases are listed with specific ecological conditions:groundwater, air humidity, high pastoral or agricultural pressure.
^bO: Leaves present throughout the year.

The grass cover is dominated by annual plants: Schoenefeldia gracilis, Loudetia togoensis, Diheteropogon hagerupii, Bracharia antholata, Pennisetum pedicellatum, Cenchrus biflorus, Elionurus elegans (Graminaceae), and Zornia glochidiata (legume), to which should be added several species of Borreria (Rubiaceae) (Hiernaux, 1978).

3. Methodology of behaviour research

This consists in observing four animals of a herd—always the same ones—once a month for five consecutive days, that is to say, for 120 hours, during which period the activity of each animal (at the moment of observation) is registered every fifteen minutes: making up a total of 1920 observations in any one research period.

The activities of the cattle are classified as follows (Diallo, 1978):

a) Grazing: ingesting the fodder, licking. the soil, minor changes of position (head lowered) during browsing.

b) Rumination: chewing the foodstuff regurgitated from the stomach.

c) Watering: drinking.

d) Walking: moving from one point to another without browsing.

e)Resting: any other activity apart from those mentioned above.

Under the heading grazing, the observer specifies the type of fodder in question: grass or straw, browse, millet stubble, rice straw, regrowth.

4. Results and discussions

4.1 Animal behaviour

The results of the observations concerning the time allocated by the animals to each of their activities are listed in Table 2 and Figure 1. The seasonal variations demonstrate clearly the interaction between the availability of fodder, the management of the herd, and behaviour of the animals. Amongst them can be noted:

Table 2 Environment–management–behaviour. Seasonal variations of a few parameters

Environment Management Behaviour
Observation period	Type of pasture (biomass)	Average day temp.(C°)	Day-time grazing H/24h	Night-time grazing H/24h	Grazing time H/24h	Ruminating time H/24h	Resting time	Watering time H/24h	Walking time H/24h	Distant travellelled (Km)
July	Natural grazing (400 kg DM/ha)	27.7	8.54	0.94	6.91	4.20	10.88	0.15	1.87	12.1
August	Natural grazing (1200 kg DM/ha)	26.6	7.85	0.30	5.84	6.36	10.17	0.16	1.43	9.8
September	Natural grazing (1500 kg DM/ha)	27.1	6.65	1.55	6.43	6.30	9.63	0.24	1.37	12.9
October	Natural grazing (1200 kg DM/ha)	28.2	8.66	1.25	6.33	6.86	6.48	0.24	4.0-	20.4
November	Fields—fallows millet-first visit (1200 kg DM/ha)	23.3	7.50	2.20	8.70	7.04	7.06	0.30	1.56	14.5
December	Rice plots and fallows (200 kg DM/ha) millet fields and fallows	22.5	7.45	1.85	7.39	6.99	7.90	0.34	1.36	11.3
January	Hors easier rice plots (1500 kg DM/ha)	24.2	7.45	1.75	7.93	7.76	7.15	0.30	0.85	10.1
February	Hors easier (2500 kg DM/ha)	28.3	7.58	2.20	8.21	7.92	6.46	0.30	1.01	10.9
March	Hors easier (1000 kg DM/ha)	25.8	8.40	2.25	8.78	6.38	7.07	0.36	1.37	15.0
April	Hors easier (350 kg DM/ha)	32.8	8.45	5.80	8.54	6.53	7.14	0.24	1.51	15.1
May	Millet fields & fallows (300 kg DM/ha) 2nd visit	31.4	9.03	2.80	10.03	5.29	6.98	0.07	1.59	17.2
June	2nd visit (240 kg DM/ha)	29.2	9.15	3.75	10.41	4.97	7.08	0.06	1.45	17.2

4.1.1 The grazing time is in inverse ratio to the availability of fodder. On high-productivity pastures (July–February), the grazing period is between six and eight hours every 24 hours, but when the quantity of fodder available diminishes (March to June), the grazing time lengthens to nine to eleven hours. However, this effect of fodder quantities ceases to dominate at a biomass equal to or over 1200 kg of DM/ha. At this level, it seems that other factors such as the palatability and the degree of dispersal of fodder on rangeland have a greater effect on grazing time. For example, in August, when fodder is abundant and of high quality, the grazing time is the lowest of the year. In November, when the average biomass per hectare is equivalent to that of the month of August, the grazing time lengthens by a little more than two hours, probably due to the difference in quantity of available fodder from one area to another on the millet field fallows.
4.1.2 The shortening of grazing time during periods of great heat, indicated in the literature (Riviére, 1974), has not been confirmed in the present instance. The average temperatures in the shade at 15 h during the April-June research work were 28° and 35° respectively.
4.1.3 The management of the herd, taken here to mean the time spent at pasture, depends on the herdsman at least as far as daytime grazing is concerned. Night management is more often left to the initiative of the animals themselves, who leave for pasture at a given time. This management seems also to take account of the degree of availability of fodder. From April to June (end of dry season), the periods spent at pasture are the longest in the year.
4.1.4 Rumination depends on the quality of the fodder, thus on its digestibility, and also on the degree of ingestion. From May to July, the period when part or all of the fodder consumed is very young (early rains in May–June 1979 enabled a grass stratum to become established) and only a small quantity is ingested (May–June), the rumination periods are short: (4.20–5.29 hours per 24 hours). They increase, however, when the grass matures and with the increase in the ingestion rate (6.30–7.29 hours per 24 hours).
4.1.5 The changes caused by the environment to the times allocated by the animals to their various activities, either add to or subtract from their resting periods. For example, when fodder is abundant and of good quality (July–September), pasture and rumination periods shorten, whereas rest periods lengthen. In October, when the animals are obliged to walk ten kilometres by day to drink, because the ponds in the natural pastures are dried up and the presence of uncropped millet fields stops them from camping near to watering points, the increase in the walking periods decreases their rest periods. 
4.1.6 Walking times registered are equivalent to displacements at speeds equal or superior to 3 km/h. The classification of these periods around an average of 1.3 hours (apart from the month of October), indicated that the distances between camps, watering points, and pastures remain substantially the same at the different sites. In fact it has been noted that the herdsman always settles on the pasture which he has decided to utilize at a distance of 0.5 or 1 km from watering points (ponds or irrigation canals).

4.2 The proportion of grazing time spent on browse

The proportional grazing periods for the various fodder species are noted in Table 3.

Table 3 Proportions of grazing time spent on different feeds (value expressed as percentage of daily grazing time)

Observation period	July	August	September	October	November	December	January	February	March	April	May	June
Daily grazing time (hours)	6.91	5.84	6.43	6.33	8.07	7.93	7.93	8.21	8.78	8.54	10.03	10.41
%time spent on grass or brush straw	99.1	100	98.6	73.4	43.4	49.7	–	–	–	–	84.30	99.7
%time spent on browse	0.9	0	1.4	26.6	2.0	13.0	3.9	–	–	–	4.0	0.3
%time spent on millet stubble	–	–	–	–	54.6	11.6	4.1	–	3.8	–	–	–
%time spent on rice straw	–	–	–	–	–	25.7	66.0	81.8	69.0	89.5	11.7	–
%time spent on regrowth on rice plots	–		–	–	–	–	26.0	18.2	27.2	10.5	–	–

The results confirm the fact that cattle prefer grass species, even when their feed value is poor, to browse species (Peyre de Fabrègues, 1975). It is also evident that, apart from the October and December data, the animal devotes 4% or less of its day to browse. In January and May, when grass feed is of poor quality (straw), the proportion of browse grazing is around 4%. This proportion diminishes when fodder becomes green and abundant (July to September).

The almost total lack of browse on the land used from February to April (ricefields, see Table 1) added to the consumption of regrowth, explains the disappearance of browse from the diet at this period.

The behaviour of cattle as regards browse in June, October and December, indicates that the composition of the ecosystem grazed and the palatability of fodder affect this parameter.

Early rains in June promote the germination of grass, and the search for appetising green shoots seems to contribute to the neglect of browse (periods taken up by browse feeding= 0.3% of grazing time).

In October, many browse trees and shrubs lose their leaves (see Table 1):.Cattle seem to enjoy these leaves, which they can gather easily (browse fodder periods = 26% of grazing time). This increase in consumption when browse fodder is to be found on the ground implies that the gathering of fodder from the trees does not suit this species of animal, and to this should be added the observation that a certain number of widespread varieties have thorns which make it difficult for the animal to gather the leaves with its wide muzzle.

In December, the non-harvested rice fields oblige the animals to spend the night on the millet fields and fallows, which at this period have only a very poor grass stratum, due to the intensive utilization which they have undergone during the preceding months. Browse then becomes, in these areas, the most abundant fodder. The increase in consumption (13% of grazing time) seems to be due rather to necessity than to preference. This phenomenon could account for the considerable browse consumption by cattle (5–45% from the beginning to the end of the dry season) noted by Blancou et al (1978) who used, for their experiments, a pasture with a poor grass stratum, dotted with bushy or tree-covered areas.

4.3 Estimates of browse ingestion

3.1 First of all, does the time devoted to their ingestion allow an accurate estimate to be made of the proportions² of different types of fodder in the diet? The answer to this question depends, in our opinion, on the palatability and the availability of each foodstuff. Several different instances may be singled out, when the animals have different types of fodder at their disposition.

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(²) The proportions of foodstuffs in the diet are not only a function of grazing times, but also of the number of mouthfuls per minute and the weight of each mouthful. It has been noticed, during the observations made in the course of this research, that the number of mouthfuls per minute varies with the palatability of the foodstuff and the degree of its dispersion on the rangeland, and that the weight of the mouthful is a function of the concentration of dry matter in the foodstuff, and the presentation of the latter, e.g. standing foodstuff, or foodstuff already cut and left on the ground. Taking into account all these factors, the utilization of the average weight of the mouthful, and the average number of mouthfuls per minute for each period (see Table 4), calculated in quantities of DM of browse ingested, gives satisfactory results: consumption of browse per minute is substantially the same from October to January. In September, the high figure of mouthfuls/minute seems to have caused a slight overestimate of the quantity ingested.

4.3.1.1 If the most palatable foodstuff is the most abundant, the animal will devote the greater part of his pasture time to it. It can thus be concluded, with only a slight margin of error, that the diet is principally made up of this particular foodstuff (e.g. grass at the beginning of the wintering period).
4.3.1.2 If the most palatable foodstuff is quantitatively insufficient, timing will then become a very poor indication, as the animal will waste its time on shreds or small morsels, from which it will gain nothing. This has been observed with cattle on millet fields where a few bundles of cowpea leaves (vigna sinensis) had been left: 29% for the cowpea as against 71% for the stubble. The quantitative proportions of these two foodstuffs in the diet are certainly different from the eating time proportion registered.

4.3.1.3 If the foodstuff is only moderately or scarcely palatable, but available in sufficient quantity, timing may well be considered as an indication, as it can be taken for granted that each time the animal approaches the fodder it does so in order to eat it. We can thus classify browse in this category.

In general, although the times devoted to the various types of fodder do not always permit an accurate appreciation of the proportions of these foodstuffs, in the diet, when they are compared with the relevant available biomasses they do provide good indications of palatability.

4.3.2 Following this train of thought, we can estimate, using the data available from outside sources, the daily average ingestion of dry browse matter during monthly observations from September to January.

The results noted in table 4 show that the browse fodder contributions (apart from those of October and December) to daily diets are weak: 0.12 to 0.24 kg DM/day. It should be noted, however, that there is an increase in the quantities ingested as the dry season progresses.

Table 4 Estimate of quantities of dm of browse ingested daily during study periods from September to January

^aValues October to January estimated pending laboratory analysis results.

In October and December, for the above-mentioned reasons, the daily browse ingestion increases: 1.55 and 0.85 kg DM respectively: that is to say, the provision of digestible protein by month of 3.8 and 3 kg is sufficient to cover the maintenance of an TLU4 for 25 and 14 days s.

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⁽³⁾These quotas have been calculated taking into account that browse foodstuffs have an average content of 82g of digestible protein per kg of DM (Le Houérou, 1980).

⁽⁴⁾ TLU = Tropical Livestock Unit: an adult cow weighing 250 kg (Boudet, 1975).

⁽⁵⁾ The number of days has been decided on the basis of 0.6 g of digestible protein for the maintenance of 1 kg liveweight for ruminants (Riviére, 1977).

When the development of the average weights of the animals from September to February is examined (see Table 5), it can be seen that the weak weight gains registered occur precisely at the periods when the quota of browse in the ration is large: in the second fortnight of October and the first fortnight in January. The increase (plus 6 kg) in October when the ingestion of total dry matter, composed solely of brush straw and browse leaves, is the lowest for the period under consideration, could be ascribed to the contribution which browse makes to the improvement in quality of the ration.

Table 5 Development of average weight of animals in relation to feed intake

The proposition that browse foodstuffs should constitute 20–30% of the herd's ration, specially in the dry season (Le Houérou, 1979), is thus fully justified, but its realization for cattle of the system under research seems difficult, due to the presence of a relatively abundant grass cover on this season's rangeland.

Biblography

Blancou, J. et al (1978). 'Composition du pâturage naturel consommé par les bovins en milieu tropical: note sur une technique nouvelle'. Colloque rech. sur l'é1evage bovin en zone tropicale humide. Bouaké, Côte d'Ivoire, pp. 10.

Boudet, G. (1975). 'Problémes posés par l'estimation de la capacité de charge d'un "pâturage naturel" tropical'. Coll. sur l'évaluation et la cartographie des paturages tropicaux africains. CIPEA, Addis Ab6ba, pp. 269–276.

Diallo, A.K. (1978). 'Transhumance: comportement, nutrition et productivité d'un troupeau zébu de Diafarabé'. Thèse doctorat 3ème cycle, Bamako.

Hiernaux, P. (1978). 'Présentation écologique des paturages de la zone d'étude du projet CIPEA/Mali'. Rapport Mission Intensive. CIPEA, Programme du Sahel, Bamako/ Mali.

Le Houérou, H.N. (1979). 'Rô1e des arbres et arboustes fourragers dans les paturages sahéliens'. CIPEA, Addis Abéba.

Le Houérou, H.N. (1980). 'Composition chimique et valeur nutritive des fourrages ligneux en Afrique Tropicale Occidentale'. Coll. International sur les fourrages ligneux en Afrique. CIPEA, Addis Abéba.

Peyre de Fabrégues, B. (1975). 'Problémes posés par l'évaluation du potentiel fourrager ligneux en zone sahélienne'. Coll. sur l'évaluation et la cartographie des pâturages tropicaux africains. CIPEA, Addis Abéba pp. 281–284.