Livestock feed resources of Sub-Saharan Africa countries are mainly depends on natural grasses, forbs with some browse shrubs and trees (Abusuwar & Ahmed, 2010). Ethiopia has vast and substantial number of farm animals, but their productivity and economic contributions are low (Adugna, 2008). In the highlands of Ethiopia natural pasture and crop residues are the major sources of feed supply to livestock (Seyoum & Zinash, 1995; Zinash et al., 1995; Zerihun, 2002). The amount and quality of feed obtained from such sources are very low and cannot satisfy the requirements and achieved the desired level of production (Adugna, 2007; Aklilu et al., 2014; Fekede et al., 2015; Alema-yehu et al., 2017). Feed availability and quality is the major bottleneck challenges of livestock production which accounts 70% of production cost (Abd El-Hack et al., 2015; Alam et al., 2022).

In Ethiopia, shortage of feed both in quality and quantity resulted in low productivity of livestock (ILRI, 2009; Demeke et al., 2017). According to CSA, (2021) report, the main feed resources in the country are green fodder or grazing is the primary one (54.54%) followed by crop residue (31.13%). Those major feed resources are available primarily during the rainy season and become severely scarce during the long dry period of the year. During this period crop residues are the main sources of feed for livestock with low nutritional profiling quality (Abegaz et al., 2007). This situation of feed scarcity as well as low quality was challenging livestock producers to achieve the nutrient requirements of their animals (Yayneshet et al., 2008). Be-zabiha et al. (2014), reported that the performance of livestock was influenced by periodic feed production patterns, that resulted in short supply of livestock products with high pricing (Kocho et al., 2011). Furthermore the current government initiatives on irrigation scheme development projects have a paramount contribution for production of promising cultivated fodder crops under supplemental irrigation. So, cultivation of adapted and well performing fodder crops under sup-lemental irrigation can be used as a possible solution for addressing the animal feed deficit of the dry season (Mulisa et al., 2022).

Using well performing and locally available or intro-duced forage species, which adapt the local environ-mental conditions, are critically important to address the problem of feed resource scarcity. According to Berhanu et al. (2003) enhancing the utilization and adoption of improved forage could considerably imp-rove livestock productivity. Small holder farmers can possibility increase livestock production through eva-luation of high quality forages with better yield advan-tage and potential adaptation to the existing environ-mental conditions (Tessema, 1999). Evaluation of pro-mising cultivated perennial forage grass species like B.mutica_18659, C. aethiopicus, P. sphacelatum, B. decumbense, C. gayana and B. mutica_6964 under suplemental irrigation condition is one of the possible intervention strategies used to alleviate the prevailing feed scarcity challenge of the country. 

Despite their significant importance as fodder crops, there is limited information on the relative advantage of producing Bracharia, Cynodon, Penisetum and Chloris species under supplemental irrigation conditions of the area. Since productivity of these species could vary and affected by area of origin, temperature, light intensity, rainfall, soil type, fertilizer level, and by stage of maturity. Therefore, this study was planned to evaluate the performance of B. mutica_18659, C. aet-biopics, P. sphacelatum, B. decumbense, C. gayana cv. Masaba and B. mutica_6964 perennial grass species and varieties under supplemental irrigation and advice the promising cultivated fodder for livestock producers. 

Study area description

The experiment was undertaken collaborately at Won-dogenet Agricultural Research center researcher and Bangladeshi researcher. The center found at 268 km far away to the South of Addis Ababa, capital city and 14 km South-East of Shashemene. It is located at 07°19.1 North latitude, 38°30 East longitude with an altitude of 1780 meter above sea level. The average rainfall of the area is 1128 mm with 11 and 26°c of minimum and maximum temperature, respectively (Tekalegn et al., 2017).  The texture of the top soil (0-25cm) was sandy clay loam with PH 8.84 (1:2.5 soil water suspensions) and total nitrogen of 0.18.

Treatments and design 

Randomized Complete Block Design of six treatment groups of perennial grass species with three replications were used for the experiment. The six perennial fodder crop grass species employed for the study were T1 (B. mutica_18659), T2 (C. aethiopicus), T3 (P. sphacelatum), T4 (B. decumbense), T5 (C. gayana cv. Masaba), and T6 (B. mutica_6964). A total of eighteen experimental plots of each with 12m2 (4m*3m) areas were utilized for fodder establishment. The spacing used between plots and blocks was 1 m and 1.5 m, respectively. 

The six perennial grass species were planted per plot with each of 0.25 and 0.5m space of intra- and inter-row spacing. Each treatment groups were assigned randomly and independently to each experimental block. DAP fertilizer was applied at the rate of 100 kg/ha to enhance sward consolidation. Management practices of hand-weeding, pest and disease monitoring or control were done uniformly.

Data collection 

The collected data were includes agronomic performances (plot cover, stand vigor and height) and herb-age yield using quadrat sampling. Incidence of disease and insect infestation were observed and recorded.

Height of the Plant 

The height of harvested plant was taken from the ground to the tip of the plant. The average of five plant heights was taken randomly from each plot at the time of proper harvesting ages (about 50% flowering).

Estimation of Biomass Yield 

The biomass yield of perennial grass species was harvested at proper harvesting stages of 10cm above the ground. Weight of fresh biomass yield was measured from each plot by using a meter square quadrat. Sub-samples of 200gm weights were taken from each plot to the laboratory, upon arrival at laboratory it was oven dried for 72 hours at temperature of 65°c. Total dry matter yield content was determined from oven-dried sample weight. Then the result was converted in to dry matter ton per hectare for comparison (Aklilu & Ale-mayehu, 2007). 

Data Analysis

Quantitative data sets were analyzed by GLM of Statistical Analysis System (SAS, 2002) procedures of version 9.0. Least significant difference (LSD) test was employed for variables whose F-values declared a significant difference (P<0.05). The statistical model for data analysis was

Yijk= μ + Si + Yj + SYij + Bk + eijk

Where, 

Yijk = dependent variables; 

μ = grand mean; 

Si = effect of perennial grass species i; 

Yj = effect of year j; 

SYij = interaction effect of perennial grass species and year ij; 

Bk = effect of block k; and 

eijk = random error effect of species i, year j, interaction of year and species ij, and block k.

Overview performances of perennial fodder grass species

Table 1: Overview performance evaluation of perennial fodder grass evaluated under supplemental irrigation condition.

Analysis of variance for the variables used to measure the performances of perennial fodder grass was shown in Table 1. There were a variation on agronomic per-formance among perennial grass species (P<0.001) and also across years (P<0.05). Furthermore, the dry matter yield in ton per hectare as well as its contents were showed variation (P<0.001) between perennial grasses and also over years. There were also an effect (P<0.05) of species by years found on cover, vigor, height and dry matter contents of the perennial grass species. 

Table 2: Cover vigour and height of perennial grass species across treatments.

Cover vigor and height of perennial grass species across treatments

Table 3: Cover vigour and height of perennial grass species over years.

The agronomic performance of cover, vigor and height were varied statistically (P<0.001) among perennial grass species (Table 2). The lowest (P<0.001) percent-age values of cover and vigor were recorded by T5 (Chloris gayana) than the other perennial grass species. Regarding to the fodder grass species height, T3 (Penicetum sphacelatum) was the tallest (P<0.001) one while T4 (Brachiaria decumbense) measured the lowest (P<0.001) height. Similarly, the year by peren-nial grass species interaction effects of cover (P<0.05), vigor (P<0.05) and height (P<0.001) were showed variations over treatments. 

Table 4: Dry matter yield and content of perennial grass species across treatments.

Among the perennial grass species P. sphacelatum, B. mutica_6964 and C. aethiopicus recorded higher hei-ght of 208.1, 182.2 and 172.7 cm, respectively. The height of B. decumbense (142.2 cm) and C. gayana (150.7 cm) of the present study were found higher than that reported by Mulisa et al. (2022), who found 80.07 and 93.23 cm, respectively. The differences in agro-nomic performances of those perennial grass species might be resulted due to soil characteristics and envi-ronmental conditions of the area. More importantly the morphological and physiological growth habits of the P. sphacelatum and C. aethiopicus grass species had a vertical growth habit than the other grass species. So plant height can be attributed to the morphological and physiological differences among the cultivars (Akinyi Nguku, 2015).

Table 5: Dry matter production and contents of perennial grass species over years.

Cover vigor and height of perennial fodder grass species over years The agronomic performance of cover, vigor as well as height of perennial fodder grasses over years was sho-wed in Table 3. The cover and vigor percent values of perennial grass species were revealed variations (P<0. 05) over years of harvesting periods. Furthermore, the heights of those perennial grass species harvested during first year period (195.7cm) were higher (P<0. 001) than the consecutive harvest years (174.7 and 142.3cm). There were also treatment by years inter-action effects of cover (P<0.05), vigor (P<0.05) and height (P<0.001) of perennial grass species across years. This might be attributed due to environmental conditions of the area that can be suited for some of the perennial grass species.

Fig. 1: Dry matter yield in ton per hectare of perennial grass species over years.

Dry matter yield and content of perennial grass species across treatments The average dry matter yield in ton per hectare and the associated percentage values was showed on Table 4. The result revealed that, the dry matter yield in ton per hectare and dry matter content of the perennial grass species were found vary statistically (P<0.001). The highest dry matter yield in ton per hectare were obtained by P. sphacelatum (22.85) followed by B. decu-mbense (16.86 ton ha-1), B. mutica_6964 (12.94 ton ha-1) and C aethiopicus (12.53 ton ha-1). Mulisa et al. (2022) reported a lower average dry matter yield in ton per hectare for B. decumbens ILRI_10871 (12.58 ton ha-1). However, the author was found a comparable dry matter yield in ton per hectare for B. decumbens ILRI_13205 (17.15 ton ha-1) accession with this report of B. decumbense (16.86 ton ha-1). The average dry matter yield of these perennial grass species (14.77 ton ha-1) were lower as compared to Desho grass species (25.05 ton ha-1) evaluated under similar environmental conditions (Tekalegn et. al., 2017). Among the perennial grass species, C. gayana, P. sphacelatum and C. aethiopicus were provided higher (P<0.001) dry matter contents of 43.2, 41.7 and 40.6%, respectively. More importantly, there were an interaction effects (P<0.05) in dry matter contents of perennial grass species by years. Relatively, the dry matter yields and content of P. sphacelatum followed by C. aethiopicus perennial grass species were per-formed better than the other cultivated fodder grass species. Even though B. decumbense has produced good dry matter, its dry matter contents was founds to the lowest (P<0.001) than P. sphacelatum and C. aethiopicus perennial grasses. The variations in dry matter production potential and its content might be re-sulted due to variations in genotypes of the perennial fodder grass species.

Average dry matter production and contents of perennial grass species over years

The average dry matter production in ton per hectare was revealed that (Table 5), the highest (P<0.001) yield (20.3 ton ha-1) were obtained at the second year of harvest than the first (12.65 ton ha-1) and third (11.36 ton ha-1) year harvests. The overall mean dry matter yield produced by those perennial fodder grass species were 14.77 ton ha-1. Consequently, the highest (P<0.001) dry matter content of the perennial grass species was also found during the second year harvest (50.1%) than the first (25.8%) and third (40.0%) year harvests. Even though, the result showed that no effects (P>0.05) of treatment by year found on dry matter production ton per hectare, there was an interaction effects (P<0.05) of dry matter contents of the perennial grass species over years.

Dry matter production potential of perennial grass species over years

The dry matter production in ton per hectare of perennial grass species over years were indicated in Fig. 1. Across all harvesting years of the perennial grasses species, P. sphacelatum produced highest dry matter production in ton per hectare than other grasses. More-over, at the second years of harvesting period most of the perennial grasses species were provided better dry matter production in ton per hectare than the first and third years of harvests. Majority of the perennial fod-der crops were tend to increase their dry matter pro-duction to the maximum and start to declining then after. The lowest yield in ton per hectare was recorded by C. gayana at the first year (8.5 ton ha-1) and third year (8 ton ha-1) harvests. Similarly, B. mutica_ 18659 

Fig. 2: Dry matter percent of perennial grass species across years.

provided the lowest yield (12.9 ton ha-1) at the second harvest period. Mulisa et al. (2022) found lower dry matter yield in ton per hectare for B. decumbens ILRI_10871 (1.46 and 9.75 ton ha-1) and B. decumbens ILRI_13205 (0.51 and 12.34 ton ha-1) at both first and second year of harvest, than this study for B. decumbens (11.7 and 25.1 ton ha-1). The dry matter production potential of C. gayana cv. Massaba at the first year (8.75ton ha-1) and second year (17.71 ton ha-1) harvest reported by Mulisa et al. (2022) were in agreement with this findings (8.5 and 17.8. ton ha-1, respectively). However, the author reported a higher dry matter production in ton per for the abovementioned perennial grasses at the third year harvests. The variation in dry matter yields of perennial grass species might be attributed due to genotypes, soil characteristics and environmental conditions of the areas.

Dry matter content of perennial grass species over years

Dry matter contents of perennial grass species over years was indicated in Fig. 2. The result revealed that the average dry matter contents of the perennial grass species were higher at the second harvest than the first and third harvest. At the first, second and third har-vests P. sphacelatum, C. gayana and C. aethiopicus have higher dry matter contents of 31.9, 59.5 and 424.2%, respectively. 

In Ethiopia feed resource availability and quality are the major challenges of livestock production. Identifying best performing perennial fodder crops under supplemental irrigation condition is critically import-ant in addressing the bottle-neck problems of feed resources. The result of this study founds a variation on agronomic performances and dry matter yield in ton per hectare and its contents of perennial fodder grass species. At the period of the second years of harvest most of the perennial grasses species were provided better dry matter production in ton per hectare than the first and third years of harvests. Among the perennial grass species P. sphacelatum and C. aethiopicus was the best performing ones in dry matter yield (22.85 and 12.53 ton ha-1) and associated contents (41.7 and 40.6%), respectively. Furthermore, there were also interaction effects of both agronomic and dry matter content performances of perennial grass species over years. Therefore, small holder farmers can preferably advised to use P. sphacelatum and C. aethiopicus perennial grass fodder crops as livestock feed resources under supplemental irrigation conditions.

We thank the Ethiopian Institute of Agricultural Research (EIAR) and Bangladeshi researcher for financial support of this research. Furthermore we appreciate to our dedicated technical assistance staffs of Mrs. Desta Fekadu, Mr. Melaku Beshir and Mr. Awol Mohammed, who were energetically involved in managing the field and data collection during the research work.

The authors declare no conflict of interest.