The study covered the Far North Region of Cameroon. The region covers an area of 34,260 km² (Figure 1). The annual rainfall in this region varies from 500 to 900 mm per year, with averages between 750 and 800 mm. The rainy season lasts only four to five months. The Mandara Mountains are wetter with an average annual rainfall of 900 mm; the less rainy areas are the Diamaré (750 mm) and Logone (450 mm) plains. The vegetation consists of wooded savannah, a poorly developed herbaceous cover, and forest galleries.

Figure 1. Map of the Far North region.

The choice of satellite imagery focused on the Landsat vector, whose sensor characteristics include channels in the visible and mid-infrared, useful for discriminating land cover classes [4]. These images were selected based on visual assessment and the metadata of cloud cover available in the image download package for the area of interest. The cloud cover percentage values range from 0.09% to 29%. Percentages below 5% cloud cover are the most dominant. The resolution of the Landsat images used is 30 m in multispectral for the year 2025. The acquisition periods are from September to October of the year. Thus, for the year, the selected images have the following characteristics: Image ID (image identification code), Image Date (date of image acquisition by the satellite sensor), % Cloud Cover, WRS Path/Row (location characteristics of the image on a Landsat grid), Satellite Sensor (instrument measuring electromagnetic radiation reflected by objects on the ground in different wavelengths), Service Years (year of satellite commissioning and decommissioning). Based on visual analysis, the set of color composites, and the analysis of different spectral signatures of objects on the image, we detected a number of land cover classes. The retained classes are as follows (Figure 2):

Herbaceous savannah: light green and lemon greenWooded savannahBare soil and built-up areasWater surfaceCropland

Figure 2. Herbaceous savannah (a) (b), Wooded savannah (c), Bare soil and built-up areas (d), Water surface (e), and Cropland (f).

The spectral signatures and land cover classes, such as herbaceous savanna and cropland, were directly correlated with field-verified data on forage species abundance, where classes like “herbaceous savanna” were found to be dominated by key forage grasses such as Pennisetumpurpureum, Cynodondactilon, Eragrostistef, Dactylisglomerata, Dactylocteniumaegyptium and Panicumrepens, while “wooded savanna” indicated the prevalence of browse species like Acaciaalbida, Paliostigmareticulatum, Faidherbiaalbida and Balanitesaegyptiaca.

The departments where cattle, goat, and sheep rearing were most representative were identified at the Regional Delegation of Livestock, Fisheries, and Animal Industries of the Far North Cameroon. These were the departments of Mayo-Tsanaga, Mayo-Kani, Mayo-Danay, Mayo-Sava, and Diamaré. In these different departments, the snowball principle was used to identify the various breeders with a minimum of two years of experience in the field and having a significant herd (minimum 10 head). Based on a data collection form, breeders were asked to provide information on the forage species consumed by livestock, their vernacular names, the parts of plants consumed, their level of palatability to the animals. Subsequently, with the permission of the breeders, direct observation of animals on the range was conducted to identify the grazed resources and their phenological stage at the time of grazing. The number of breeders surveyed, broken down by department, I summarized in the following Table 1.

Table 1. Questionnaire distributions in the different Divisions of Far North Cameroon.

Forage species were identified based on botanical guides and by consulting researchers specialized in the field. The botanical guides used were Geerling’s guide to woody plants [5], Van der Zon’s Grasses of Cameroon [6], Merlier and Montegut’s Tropical Weeds [7]. According to the different guides listed, the identification of forage plants is based on their morphological characteristics, which differ from one plant to another by the shape of flowers, stems, and leaves. Species that could not be identified on site were taken to the National Herbarium of Cameroon (H.N.C) for taxonomic identification.

To assess herbaceous biomass productivity, the complete harvest method [8] was used. The harvest was done inside unit plots of 1 m² (Figure 3). About ten plots were distributed randomly on the rangeland as recommended by [9]. Thus, on each vegetation unit, the randomly distributed unit plots were completely mowed using shears at a height of 5 cm from the ground. For each vegetation unit, a total of 3 mowings were performed. After mowing, the following operations were carried out: recording the wet weight of the total biomass using a 5 kg ± 50 g spring balance; performing manual sorting by separating consumed forage species from non-consumed species. Subsequently, a 100 g forage sample was taken, then dried in an oven at 60˚C until a constant dry weight was obtained after two or three weighings in the laboratory. From the dry weights of the samples, the biomass production in dry matter per hectare was obtained by extrapolation. To obtain the average biomass production per plot, divide the productions obtained during the three successive mowings by three, which gives the average phytomass per vegetation unit.

Figure 3. Installation of a 1 m² plot.

The leaf biomass of woody forages consumed by cattle was assessed in the different survey areas. The method used is known as the non-destructive method as described by [10]. It first consists of determining the density of a species using the following formula:

With N: the number of individuals of a species in the survey and S the sampled area (0.25 ha = 2500 m²).

Then, two individuals of each woody forage were chosen at random to assess the leaf biomass. The total number of branches per individual was counted (Nbr) and the leaf biomass of two randomly chosen branches were cut and weighed (BMbr) using a 5 kg capacity spring balance (Figure 4). Samples of 150 g of leaves were taken per branch and placed in an oven at 60˚C for 72 hours for the determination of dry matter using the formula:

The dry leaf biomass of each individual (LBInd) of woody species was calculated using the formula:

LBInd (kg DM/plant) = BMbr × Nbr × %DM

With LBInd: Leaf biomass per individual; BMbr: average biomass of the cut branches; NBr: Total number of branches counted and DM: Dry Matter.

The estimation of the average dry leaf biomass (LBA) per hectare for a species was calculated using the density of individuals of the corresponding woody forage species using the formula:

LBA (kg DM/ha) = LBInd × D

With LBInd: Leaf biomass per individual and D: the density of individuals for the considered woody species.

Figure 4. Pruning branches and weighing leaf biomass.

According to [11], the weight of tropical cattle ranges between 200 to 400 kg, which allows defining the tropical livestock unit (TLU) as corresponding to a maintenance bovine of 250 kg. Also, according to the same author, it is estimated that 1/3 of the biomass is the actual forage available for consumption by cattle, and 6.25 kg is the daily dry matter consumption of the TLU on pasture. The animal load (CC) for a given period, expressed in T.L.U./ha/year, is calculated as follows:

With 6.25 = daily consumption of one TLU (TLU: Tropical Livestock Unit); k = utilization coefficient (k = 0.33); DM: dry matter.

Data on biomass and carrying capacity were subjected to one-way ANOVA. Duncan’s test at a 5% significance level was used for mean separation. SPSS 20.0 software was used to perform the ANOVA [12].

3.1.1. Herbaceous Plants

In the Far North region, a total of 16 herbaceous plant species were listed in the Diamaré department. These species belong to 2 families, namely Poaceae (13 species) and Fabaceae (3 species) (Table 2). In the Mayo-Sava department, a total of 6 herbaceous plant species were listed, belonging to 3 families: Poaceae (4 species), Fabaceae (1 species), and one species of Malvaceae. In the Mayo-Tsanaga department, a total of 10 herbaceous plant species were listed, belonging to 3 families: Poaceae (8 species), Juncaceae (1 species), and one species of Cyperaceae. The Mayo-Danay department listed a total of 16 herbaceous plant species belonging to 3 families: Poaceae (14 species), Fabaceae (1 species), and one species of Cyperaceae. The Mayo-Kani department listed a total of 17 herbaceous plant species belonging to 3 families: Poaceae (13 species), Cyperaceae (3 species), and one species of Juncaceae.

Table 2. Herbaceous species listed in the far north region.

3.1.2. Woody Plants

In the pastures of the Far North, a total of 7 woody species belonging to 7 families were listed in the Diamaré department: Fabaceae (3 species), Zygophyllaceae (1 species), and one species each of Meliaceae, Apiaceae, and Malvaceae (Table 3). In the Mayo-Sava department, a total of 7 woody species belonging to 6 families were listed: Fabaceae (2 species), Cannabaceae (1 species), Capparaceae (1 species), Apiaceae (1 species), Meliaceae (1 species), and Rhamnaceae (1 species). In the Mayo-Tsanaga pastures, a total of 5 woody species belonging to 4 families were listed: Fabaceae (2 species), Apiaceae (1 species), Meliaceae (1 species), and Zygophyllaceae (1 species). In the Mayo-Danay department, a total of 6 woody species belonging to 4 families were listed: Fabaceae (3 species), Combretaceae (1 species), Capparaceae (1 species), and Meliaceae (1 species). Four woody species belonging to 3 families were listed in the Mayo-Kani department: Fabaceae (2 species), Zygophyllaceae (1 species), and Combretaceae (1 species).

Table 3. List of woody species listed in the far north region.

Figure 5. Proportion of Herbaceous and woody species listed by department in the far north region.

Figure 5 illustrates the proportion of herbaceous and woody species listed by department in the Far North region. It shows that the proportion of herbaceous species is higher in the Diamaré, Mayo-Tsanaga, and Mayo-Kani departments (26.67%, 16.67%, and 20% respectively). In contrast, the pastures in the Mayo-Sava department of the Far North of Cameroon are predominantly populated by woody species (23.33%). In the Mayo-Danay department, the proportions of herbaceous and woody species are similar.

Table 4 presents the parts of herbaceous plants consumed, their preferences, and the type of livestock that consume these resources. It shows that the plant parts consumed are leaves, stems, flowers, and fruits. The herbaceous plants most consumed by livestock in the Diamaré department are Pennisetumpurpureum, Zorniaglochidiata, Zornialatifolia, and Echinochloacrus-galli. Zornialatifolia is the most consumed herbaceous plant by livestock in the Mayo-Sava department. In the Mayo-Danay department, the herbaceous plants most consumed by livestock are Digitarialongiflora, Eragrostiscurvula, Eragrostisspectabilis, Dactylocteniumaegyptium, and Zorniaglochidiata.

Table 4. Parts and preferences of herbaceous plants consumed by livestock scientific names PCP preferences livestock type.

PCP: Part of Plant Consumed; *: Low consumption; **: Medium consumption; ***: High consumption.

Figure 6. Proportion of herbaceous plant parts consumed by livestock.

Figure 6 illustrates the proportion of plant parts consumed by livestock according to department in the Far North region. It shows that regarding herbaceous plants in the Diamaré department, the majority of livestock consume leaves + stems + flower (81.25%), followed by leaves + stems + fruit (12.50%), and finally leaves + stems (6.25%). In the Mayo-Sava department, livestock consume only leaves + stems + fruit (100%). In the Mayo-Tsanaga department, livestock predominantly prefer leaves + stems + flower (90%) and, to a lesser extent, leaves (10%). In the Mayo-Danay department, livestock consume leaves + stems (68.75%), followed by leaves + stems + flower (18.76%), and finally leaves (12.50%). Leaves + stems + flower are more consumed by livestock in the Mayo-Kani department (83.33%), followed by leaves + stems (8.33%) and leaves (8.33%).

Table 5 presents the parts of woody plants consumed, their preference, and the type of livestock that consume these resources. It follows that leaves, flowers, fruits, and stems are the parts of woody plants consumed by livestock. In the Diamaré department, the woody plants most consumed by livestock are Balanitesaegyptiaca, Faidherbiaalbida, Piliostigmareticulatum, Acaciaalbida. Faidherbiaalbida, Khayasenegalensis, Acaciaalbida, and Ziziphusmauritiana are the most consumed woody plants in the Mayo-Sava department. In the Mayo-Tsanaga department, the same trend is observed where Faidherbiaalbida, Khayasenegalensis, and Acaciaalbida are the most consumed woody plants. Similarly, the most consumed woody plants in the Mayo-Danay department are Balanitesaegyptiaca, Khayasenegalensis, Faidherbiaalbida, and Acaciaalbida. In the Mayo-Kani department, the most consumed woody plants are Balanitesaegyptiaca, Faidherbiaalbida, and Acaciaalbida.

Table 5. Parts and preferences of woody plants consumed by livestock.

PCP: Part of Plant Consumed; *: Low consumption; **: Medium consumption; ***: High consumption.

Figure 7 illustrates the proportion of plant parts consumed by livestock according to department in the Far North region. It shows that regarding woody plants in the Diamaré department, the majority of livestock consume leaves (100%). In the Mayo-Sava department, livestock consume leaves (74.42%), followed by leaves + stems (14.28%) and leaves + flower (14.28%). In the Mayo-Tsanaga department, livestock predominantly prefer leaves (75%) and, to a lesser extent, leaves + stems (25%). In the Mayo-Danay department, livestock consume leaves (80%), followed by leaves + stems (10%) and leaves + stems + fruits (10%). Leaves are more consumed by livestock in the Mayo-Kani department (50%), followed by leaves + stems (25%) and leaves + stems + fruits (25%).

Figure 7. Proportion of woody plants according to their preference by livestock.

In the departments of the Far North region, the different pastures studied showed that pastures P2, P3, and P4, rich in Eragrostistef, Dactylisglomerata, and Zornialatifolia respectively, have the highest biomass productivities (2146.80 ± 79.03^a kg DM/ha, 2638.60 ± 400.36^a kg DM/ha, and 2345.60 ± 129.22^a kg DM/ha), while plots P1 and P5, rich in Dactylocteniumaegyptium and Cynodondactylon, present the lowest values (Table 6).

Table 6. Biomass Productivity of different pastures in the departments of the far north region.

Legend: a, b: means with different letters are significantly different (P < 0.05). P1: Pasture rich in Dactylocteniumaegyptium; P2: Pasture rich in Eragrostistef; P3: Pasture rich in Dactylisglomerata; P4: Pasture rich in Zornialatifolia; P5: Pasture rich in Cynodondactylon. MS: Mayo-Sava; MT: Mayo-Tsanaga; MD: Mayo-Danay; MK: Mayo-Kani; D: Diamaré.

Regarding woody species, Table 7 presents the biomass production per hectare for each species, obtained based on their leaf biomass. It shows that the woody species with significantly the highest biomass are Faidherbiaalbida (138.00 ± 2.12^a kg DM/ha) and Piliostigmareticulatum (135.83 ± 0.28^a kg DM/ha), followed by Balanitesaegyptiaca (117.58 ± 7.63^b kg DM/ha), Steganotaeniaaraliacea (118.42 ± 6.61^b kg DM/ha), and Acaciaalbida (117.01 ± 2.44^b kg DM/ha). Azadirachtaindica and Adansoniadigitata present the lowest values (11.64 ± 1.71^c kg DM/ha; 11.90 ± 1.22^c kg DM/ha respectively).

Table 7. Biomass productivity of woody species in the far north Cameroon.

Legend: a, b, c: means with different letters are significantly different (P < 0.05).

In the Far North region, regardless of the department concerned, pastures P1 rich in Dactylocteniumaegyptium, P2 rich in Eragrostistef, and P3 rich in Dactylisglomerata have significantly (p < 0.05) higher carrying capacities than those of pastures P4 rich in Zornialatifolia and P5 rich in Cynodondactylon (Table 8).

Table 8. Carrying capacity of pastures rich in herbaceous plants by department.

Legend: a, b: means with different letters are significantly different (P < 0.05). P1: Pasture rich in Dactylocteniumaegyptium; P2: Pasture rich in Eragrostistef; P3: Pasture rich in Dactylisglomerata; P4: Pasture rich in Zornialatifolia; P5: Pasture rich in Cynodondactylon. MS:Mayo-Sava; MT: Mayo-Tsanaga; MD: Mayo-Danay; MK: Mayo-Kani; D: Diamaré.

Regarding pastures rich in woody plants, the carrying capacity is very low (Table 9) compared to herbaceous plants. Nevertheless, the highest carrying capacities were recorded for Faidherbiaalbida (0.0169 ± 0.0068^a) and Piliostigmareticulatum (0.0165 ± 0.0068^a), followed by Balanitesaegyptiaca (0.0079 ± 0.0042^b kg DM/ha), Steganotaeniaaraliacea (0.0079 ± 0.0042^b kg DM/ha), and Acaciaalbida (0.0079 ± 0.0042^b kg DM/ha). Azadirachtaindica and Adansoniadigitata present the lowest values (0.0016 ± 0.0018^c kg DM/ha; 0.0016 ± 0.0018^c kg DM/ha respectively).

Table 9. Carrying capacity of fodder woody plants in the far north region.