Exploring the Nutritional Potential of Wild Grass Fodder for Mega Herbivore (Elephas maximus) in the Foothills of Western Ghats.

An elephant, being a mega herbivore, consumes large amounts of food. Due to the lack of availability of fodder inside the forest, the elephants move out of their habitat areas and also find agricultural crops attractive, which further results in man-animal conflict. To improve the elephant habitat area, the current study was conducted to assess the availability of native fodder grasses inside the Coimbatore Elephant Reserve, Western Ghats, from April 2021-April 2022. The area falls between 10°37'and 11°31' North latitudes and 76°39'and 77°5' East longitudes. It was approached in a systematic random sampling method. A total of 128 sample plots of 1 sq.m size were randomly placed, and the density of grass species was recorded in percentage (%). The collected samples were shade dried for one week, ground to pass through a 1 mm sieve, and stored in polythene bags. Furthermore, the samples were chemically analyzed to determine their nutritional values. The dry matter (DM) content of various grass fodder varied from 28.18% to 59.75%. The crude protein (CP) content differed between 5.94% and 11.94%. The highest CP was recorded in Cynodon dactylon (11.94%) and the least in Aristida setacea (5.94%). Ether extract content was found in the ranges of 1.00% to 5.00%. The acid detergent fibre (ADF) content of Aristida setacea (45.74%) was observed as the highest, whereas the lowest was observed in Oplismenus burmannii (26.78%), followed by Themeda triandra (26.85%), Heteropogon contortus (30.12%) and Enteropogon monostachyos (30.31%). The average neutral detergent fibre content of grass fodder was 52.27%, with a range of 37.89% (Oplismenus burmannii) to 67.87% (Cymbopogon martinii). The average total digestible nutrient (TDN) content of grass was 77.45%; relative forage quality (RFQ) exhibited wider variations among the grasses and ranged between 107.51 and 198.83. This study is a pioneer in evaluating the nutritional values of native grass fodder species for elephants in the Western Ghats. The study gives strategies for the selection of high nutritive fodder grass for the habitat improvement of elephants, and it also provides scientific and baseline information for the conservation of native grass fodder species in the Western Ghats.

1. Introduction

Elephants are mega herbivores and generalist foragers with a diverse diet which consists of grasses, forbs, fruits, bark, leaves, twigs and roots [1]. Owing to the unique morphology and physiology that accompanies their enormous body size, energy intake by elephants is very high, which is, however, constrained by their rate of forage quality [2]. The elephant consumes a large amount of food, estimated to be 1.5–2.5 percent of its body weight in dry weight fodder [3]. Adult elephants can consume approximately 300 kg of food per day. They can spend an average of 16–18 h per day on consumption. Due to this enormous need for food, elephants cannot afford to be highly selective feeders. In order to meet their fodder requirements, elephants move an average distance of 40 to 50 km, fixing their home ranges, and they follow these fixed routes annually every season [2,4]. Unfortunately, the umbrella species of the forest face a severe crisis due to the limitation of food in the forest territory areas. These factors drive the elephants from the forests to the associated fringe villages in search of food. A paradigm shift from conventional cropping to cash crops such as bananas and corns, often referred to as tempting crops for elephants, and its proximity to the elephant corridors, further attract theses gentle giants to come out of the forests. According to the reports of the WWF, India, in 2017, it wasestimated that approximately 301 elephants and 245 people are killed annually due to human–elephant conflicts in India. In addition, 500,000 families are affected every year by crop destruction and other human–elephant conflict-related issues [5]. Hence, habitat management is critical in adopting elephant conservation strategies in the Western Ghats. Incorporating ideal fodder species into the elephant habitat is one of the key elements in elephant habitat management. The seasonal movement and habitat selection of elephants are largely determined by their foraging behaviour [1]. Reports reveal that elephants in southern India intake heavy graminoids during the wet season [1],with it constituting 84.6% of their diet [6]. Grasses form a natural homogenous group of plants with remarkable diversity, and they play a significant role in the lives of wild animals [7]. They play a crucial role in the maintenance of the world’s ecosystems and biodiversity [8]. Studies on wild grasses, especially their fodder value, have become very important recently for the restoration of degraded ecosystems. Herbivores’ food resource selection is highly variable, and it can be influenced by the nutritional and energetic properties of the food plants. Henceforth, a deep understanding of the nutritional and energetic properties of the food plants consumed by elephants is essential to comprehend the feeding pattern and the selection of fodder plants by Asian elephants [9]. This alsoplays a crucial role in fostering habitat management strategies for elephant conservation in different phytogeographical regions of the Western Ghats. With this background, the present study has been conceived to explore the diversity of grasses around the Coimbatore Elephant Reserve and to evaluate their nutritional value.

2. Materials and Methods

Study area: The present study was conducted in the Mettupalayam and Sirumugai ranges of Coimbatore Forest Division, Western Ghats, Tamil Nadu, India, from April 2021–April 2022. The area falls between 10°37′and 11°31′ North latitudes and 76°39′and 77°5′ East longitudes. A greater part of the division is situated southwards in the Western Ghats, with the north-western parts forming the lower ranges of the Nilgiris. The elephant habitat area represents 20,000 ha of the study area, which was approached in a systematic random sampling method. A transact line of 2 km length was marked in the study area for exploration and documentation of grasses. For that, a 1 sq.m bamboo frame was randomly placed, and the density of grass species was recorded as apercentage (%) [10]. A sampling intensity of 0.2% was used. Sample plots (1 m×1 m) were laid in the opposite direction, and the distance between the sample plots were fixed as 200 m and 50 m from the transect line. A total of 128 sample plots was laid out in 6 beats of the Mettupalayam range and Sirumugai range, viz., Jaccanari, Sundapatti, Nellimalai, Hulikal, Kandiyur, Kallar, Odanthurai, Kunjapanai, Pethikuttai, Koothamundi north, Koothamundi south and Uliyur beat. The respective GPS points were recorded using a Gramin 60 version GPS. By using the geo-referencing points, the plots were marked on the Google Earth Map by using Google Earth Pro software, version 7.3 (Figure 1). Thesamplesof grass species collected from the plots were identified using their local names, whereas their scientific names were identified with the help of a book named “A handbook of Some South Indian grasses” [11]. Based on the survey and direct and indirect evidence of the feeding behaviour of elephants (Figure 2), 30 grass fodder species were catalogued, and the samples were collected for nutritional analysis.

Figure 1

Map shows 1 × 1 m size of sample plots for grass fodder in the study area. (SP- Sample plot numbers).

Figure 2

Direct feeding behaviour (grass fodder) of elephants in the study area.

Proximate analysis: The grass fodder samples were collected from the forest and were cut into small pieces so as to facilitate easy handling and uniform sampling for analysis. Samples were shade dried, and the dried samples were then ground to pass through a 1 mm sieve and were stored in polythene bags. The samples were chemically analyzed with three replications to determine their dry matter (DM), crude protein (CP), crude fibre (CF), ether extract (EE) and ash content (AC) using the AOAC [12] method; acid detergent fibre (ADF) and neutral detergent fibre (NDF) were determined as per Van Soest [13]; total digestible nutrient (TDN) and metabolizable energy (ME) as per Moran [14]; digestible dry matter (DDM) and dry matter intake (DMI) calculated as perSchroeder [15]; and relative forage quality (RFQ) calculated as perMoore and Undersander [16].

Statistical analysis: To compare the treatment means, the Tukey test was performed using the Statistical Package for Social Science data (SPSS) software, and the graphs were formed using Paleontological statistical software (PAST) version 3.

3. Results

The DM content of various grass fodder for elephant feeding varied from 28.18 ± 1.66% to 59.75 ± 4.00%. Most of the samples contained over 30% dry matter. The highest dry matter values were observed in Arisida setacea (59.75 ± 4.00%), followed by Eragrostis cilianensis (59.15 ± 2.25%), Alloteropsis cimicina (57.35 ± 2.64%) and Perotis indica (57.35 ± 2.49%). The ash content was found to be in the range of 1.60 ± 0.09% (Eremochloa ophiuroides) to 8.85 ± 0.18% (Themeda triandra). It was observed to be highest in Cynodon dactylon (11.94 ± 0.80%), followed by Themeda trinadra (11.81 ± 0.93%), Heteropogon contortus (11.69 ± 0.75%), Dichanthium aristatum (11.56 ± 0.49%) and the lowestin Aritistida setacea (5.94 ± 0.22%). The average crude protein content of the grass was 8.11%. Ether extract content was found in the range of 1.00 ± 0.00% to 5.00 ± 0.31%. The crude protein content varied between 5.94 ± 0.22% (Aristida setaceae) and 11.94 ± 0.80% (Cynodon dactylon). The highest EE was observed in Cymbopogon martini (5.00 ± 0.31%), followed by Enteropogon monostachyos (4.67 ± 0.37%), Heteropogon contortus (4.33 ± 0.29%) and Hyparrhenia hirta (4.33 ± 0.17%) (Table 1).

Table 1

Nutritional value of native grass fodder species (%).

	Species Name	DM	AC	CP	EE
1.	Alloteropsis cimicina	57.35 ± 2.64abc	4.25 ± 0.27fg	6.75 ± 0.19fg	1.67 ± 0.15gh
2.	Apluda mutica	47.79 ± 1.07efgh	7.10 ± 0.01cd	7.50 ± 0.37cdef	3.00 ± 0.05c
3.	Acrachne racemosa	40.26 ± 1.09ijkl	3.15 ± 0.21ij	6.31 ± 0.37fg	2.67 ± 0.14de
4.	Aristida setacea	59.75 ± 4.00a	3.00 ± 0.12jk	5.94 ± 0.22g	2.00 ± 0.01fg
5.	Brachiaria semiundulata	54.01 ± 4.62abcde	1.85 ± 0.14lm	6.44 ± 0.15fg	1.33 ± 0.02hi
6.	Bromus diandrus	53.80 ± 1.03abcdef	2.35 ± 0.14l	6.81 ± 0.34efg	2.33 ± 0.19ef
7.	Bulbostylis barbata	33.33 ± 1.11lmno	2.40 ± 0.06kl	6.75 ± 0.18fg	1.33 ± 0.11hi
8.	Cenchrus ciliaris	41.27 ± 1.05hijk	6.90 ± 0.02d	6.38 ± 0.45fg	2.67 ± 0.13de
9.	Chloris barbata	50.75 ± 3.91cdef	3.35 ± 0.20hij	7.31 ± 0.36cdef	1.00 ± 0.08i
10.	Chloris virgata	48.48 ± 0.48defg	3.45 ± 0.18hij	7.25 ± 0.36cdef	1.00 ± 0.00i
11.	Chrysopogon aciculatus	55.07 ± 3.01abcd	5.10 ± 0.24e	9.88 ± 0.15b	1.33 ± 0.06hi
12.	Cymbopogon martinii	46.63 ± 1.47fghi	4.35 ± 0.32fg	8.00 ± 0.14cde	5.00 ± 0.31a
13.	Cynodon dactylon	47.09 ± 0.44efgh	7.90 ± 0.24b	11.94 ± 0.80a	2.33 ± 0.18ef
14.	Cyperus rotundus	32.21 ± 2.40mno	4.60 ± 0.36ef	8.06 ± 0.41cd	1.67 ± 0.07gh
15.	Dichanthium aristatum	53.37 ± 0.71abcdef	8.70 ± 0.72a	11.56 ± 0.49a	1.67 ± 0.09gh
16.	Digitaria ciliaris	34.16 ± 1.77jklmno	4.20 ± 0.04fg	7.56 ± 0.54cdef	2.33 ± 0.09ef
17.	Digitaria longifolia	37.13 ± 2.44jklmn	2.05 ± 0.03lm	7.31 ± 0.12cdef	2.67 ± 0.03de
18.	Digitaria sanguinalis	44.48 ± 1.81ghij	3.00 ± 0.24jk	6.31 ± 0.15fg	1.33 ± 0.08hi
19.	Echinochloa colona	36.87 ± 1.17jklmn	3.35 ± 0.24hij	6.81 ± 0.21efg	2.67 ± 0.02de
20.	Enteropogon monostachyos	37.40 ± 2.58ijklmn	3.70 ± 0.21ghi	10.50 ± 0.19b	4.67 ± 0.37ab
21.	Eragrostiella bifaria	55.07 ± 2.23abcd	3.25 ± 0.05ij	7.25 ± 0.46cdef	1.33 ± 0.02hi
22.	Eragrostis cilianensis	59.15 ± 2.25ab	2.15 ± 0.06lm	7.31 ± 0.31cdef	1.67 ± 0.13 gh
23.	Eremochloa ophiuroides	38.97 ± 3.49jklm	1.60 ± 0.09m	7.06 ± 0.15defg	1.00 ± 0.07i
24.	Heteropogon contortus	31.37 ± 1.96no	7.55 ± 0.37bc	11.69 ± 0.75a	4.33 ± 0.29b
25.	Hyparrhenia hirta	28.18 ± 1.66o	5.00 ± 0.30e	10.31 ± 0.01b	4.33 ± 0.17b
26.	Kyllinga brevifolia	52.51 ± 2.95abcdef	1.75 ± 0.13lm	6.81 ± 0.30efg	1.00 ± 0.06i
27.	Melinis repens	33.33 ± 1.71lmno	4.00 ± 0.33fgh	8.38 ± 0.53c	3.33 ± 0.16c
28.	Oplismenus burmannii	38.97 ± 0.57jklm	7.20 ± 0.15cd	9.94 ± 0.11b	3.00 ± 0.09cd
29.	Perotis indica	57.35 ± 2.49abc	2.15 ± 0.10lm	7.31 ± 0.63cdef	2.33 ± 0.14ef
30.	Themeda triandra	32.78 ± 0.76mno	8.85 ± 0.18a	11.81 ± 0.93a	3.00 ± 0.13c
	SEM	1.83	0.19	0.33	0.12

a SEM:standard error of mean. DM: dry matter, AC: ash content; CP: crude protein; EE: ether extract. According to theTukey test, mean values with different superscript (abcdefghijklmno) within a column are significantly different (p < 0.05). The data are expressed as mean ± Standard deviation (SD).

The maximum crude fibre content was recorded in Themeda triandra (34.63 ± 2.95%) and it was followed by Heteropogon contortus (34.38 ± 1.20%) Table 2. The maximum ADF content was observed in Aristida setacea (45.74 ± 0.25%), whereas the minimum was observed in Oplismenus burmannii (26.78 ± 1.75%), followed by Themeda triandra (26.85 ± 2.36%), Heteropogon contortus (30.12 ± 0.91%) and Enteropogon monostachyos (30.31 ± 0.13%). The average NDF content of 30 grass fodder species was 52.27% with a range of 37.89 ± 2.07% (Oplismenus burmannii) to 67.87 ± 5.23% (Cymbopogon martinii), excluding Cymbopogon martini (67.87%) and Eragrostis cilianensis (60.16%) (Table 2).

Table 2

Crude fibre and Detergent fibre components of the grass fodder species.

	Species Name	CF	ADF	NDF
1.	Alloteropsis cimicina	18.63 ± 1.01ijk	43.32 ± 1.03gh	51.23 ± 0.64cdefg
2.	Apluda mutica	24.29 ± 0.25cdef	35.45 ± 2.33bcd	52.65 ± 0.10defgh
3.	Acrachne racemosa	18.76 ± 0.77ijk	42.13 ± 2.89fgh	59.08 ± 0.85ghi
4.	Aristida setacea	21.38 ± 0.69efghi	45.74 ± 0.25h	50.87 ± 0.41cdefg
5.	Brachiaria semiundulata	20.88 ± 1.56fghi	39.76 ± 2.12defgh	48.97 ± 4.16bcde
6.	Bromus diandrus	20.13 ± 1.66ghi	42.34 ± 0.97fgh	51.23 ± 3.79cdefg
7.	Bulbostylis barbata	15.68 ± 1.29jkl	36.34 ± 2.09bcdef	56.98 ± 2.93efghi
8.	Cenchrus ciliaris	28.18 ± 1.36bc	42.34 ± 0.14fgh	52.31 ± 4.30cdefgh
9.	Chloris barbata	20.11 ± 0.02gh	39.76 ± 2.97defgh	52.43 ± 4.70cdefgh
10.	Chloris virgata	20.43 ± 0.52fghi	40.01 ± 2.93defgh	53.45 ± 0.14efgh
11.	Chrysopogon aciculatus	23.90 ± 1.17defg	39.76 ± 3.49defgh	52.65 ± 2.94defgh
12.	Cymbopogon martinii	26.86 ± 1.52bcd	40.21 ± 2.63defgh	67.87 ± 5.23j
13.	Cynodon dactylon	28.45 ± 1.40b	36.43 ± 1.97bcdef	56.32 ± 2.79efghi
14.	Cyperus rotundus	25.32 ± 1.78bcde	31.89 ± 1.02abc	52.31 ± 1.15cdefgh
15.	Dichanthium aristatum	26.33 ± 0.40bcd	34.65 ± 1.64bcd	52.87 ± 1.84defgh
16.	Digitaria ciliaris	19.35 ± 1.50ij	39.45 ± 1.89defgh	56.32 ± 4.30efghi
17.	Digitaria longifolia	10.67 ± 0.78n	36.65 ± 2.52cdef	55.76 ± 0.62efghi
18.	Digitaria sanguinalis	10.83 ± 0.74n	38.57 ± 0.40defg	58.34 ± 0.46fghi
19.	Echinochloa colona	13.26 ± 1.10lmn	35.53 ± 0.26bcde	50.84 ± 0.66cdef
20.	Enteropogon monostachyos	28.11 ± 2.34bc	30.31 ± 0.13abc	42.16 ± 0.42ab
21.	Eragrostiella bifaria	15.71 ± 0.96jkl	43.27 ± 1.09gh	58.34 ± 3.28fghi
22.	Eragrostis cilianensis	15.19 ± 1.16klm	41.89 ± 3.34efgh	60.16 ± 2.44hij
23.	Eremochloa ophiuroides	18.13 ± 0.42ijk	34.55 ± 2.64bcd	44.89 ± 0.81abcd
24.	Heteropogon contortus	34.38 ± 1.20a	30.12 ± 0.91ab	41.23 ± 0.08ab
25.	Hyparrhenia hirta	24.91 ± 1.00bcde	33.87 ± 1.13bcd	58.94 ± 2.29fghi
26.	Kyllinga brevifolia	11.31 ± 0.67mn	38.76 ± 2.89defg	44.31 ± 3.18abc
27.	Melinis repens	23.31 ± 0.95defgh	33.87 ± 1.18bcd	63.12 ± 2.08ij
28.	Oplismenus burmannii	19.91 ± 0.54hi	26.78 ± 1.75a	37.89 ± 2.07a
29.	Perotis indica	12.29 ± 0.13lmn	30.98 ± 0.39abc	42.14 ± 1.34ab
30.	Themeda triandra	34.63 ± 2.95a	26.85 ± 2.36a	42.42 ± 1.62ab
	SEM	1.00	1.63	2.09

a All values represented are on a dry matter basis. ADF: acid detergent fibre, NDF: neutral detergent fibre. According to the Tukey test, mean values with different superscript (abcdefghijk) within a column are significantly different (p < 0.05). The data areexpressed as mean ± SD.

Forage quality: Based on the primary constituents of nutritional attributes, the derived quality parameters, viz., nitrogen free extract, total digestible nutrients, digestible dry matter, dry matter intake, metabolizable energy and relative forage quality were calculated. The total digestible nutrient (TDN) content was significantly different among the species, and it ranged between 62.21 ± 5.60% (Themeda triandra) and 87.26 ± 4.66% (Digitaria longifolia). Metabolizableenergy (ME) varied significantly among the grass fodder species and ranged from 9.62 ± 0.74 MJ/Kg DM to 14.25 ± 1.11MJ/Kg DM. In the current study, the RFQ exhibited wider variations among the grasses and ranged between 107.51 ± 6.94 and 198.83 ± 7.73. RFQ was recorded in Perotis indica (198.83 ± 7.73), followed by Oplismenus burmannii (192.77 ± 4.11) and Kyllinga brevifolia (190.50 ± 11.49), whereas Cymbopogon martinii (107.51 ± 6.94) registered a minimum forage quality index (Table 3).

Table 3

Forage quality parameters of grass fodder species.

	Species Name	NFE	TDN	DDM	DMI	ME	RFQ
1.	Alloteropsis cimicina	68.70 ± 1.01bcde	79.51 ± 1.07abc	55.15 ± 2.15de	2.34 ± 0.01defg	12.82 ± 0.12abcdf	151.42 ± 3.68defg
2.	Apluda mutica	58.11 ± 2.30cfgh	73.23 ± 5.86abcde	61.28 ± 4.95abcde	2.28 ± 0.03efgh	11.66 ± 0.50dfgh	135.69 ± 3.28ghij
3.	Acrachne racemosa	69.11 ± 0.33abde	81.19 ± 5.25ab	56.08 ± 0.17cde	2.03 ± 0.07ghi	13.13 ± 1.07abcdf	134.08 ± 11.18ghij
4.	Aristida setacea	67.68 ± 3.21bcdef	79.39 ± 5.62abc	53.27 ± 2.21e	2.36 ± 0.16defg	12.80 ± 0.69abcdf	152.25 ± 3.53defg
5.	Brachiaria semiundulata	69.50 ± 3.21abcd	80.20 ± 3.79abc	57.93 ± 3.65bcde	2.45 ± 0.14cdef	12.95 ± 0.91abcdf	159.79 ± 6.96cdef
6.	Bromus diandrus	68.38 ± 1.53bcde	80.56 ± 4.75abc	55.92 ± 2.25cde	2.34 ± 0.18defg	13.01 ± 0.65abcdf	153.43 ± 8.73defg
7.	Bulbostylis barbata	73.84 ± 2.00abc	83.10 ± 1.69ab	60.59 ± 4.27abcde	2.11 ± 0.04fghi	13.48 ± 1.12abcd	142.29 ± 1.10efghi
8.	Cenchrus ciliaris	55.87 ± 1.01gh	71.16 ± 1.65bcde	55.92 ± 0.60cde	2.29 ± 0.13efh	11.27 ± 0.17fghi	132.72 ± 1.62ghij
9.	Chloris barbata	68.23 ± 4.01bcde	78.70 ± 2.33abc	57.93 ± 3.80bcde	2.29 ± 0.14efgh	12.67 ± 0.60abcdf	146.45 ± 11.04defgh
10.	Chloris virgata	67.87 ± 3.29bcde	78.42 ± 1.05abc	57.73 ± 4.65cde	2.25 ± 0.15fgh	12.62 ± 0.04abcdf	143.14 ± 7.59efghi
11.	Chrysopogon aciculatus	59.79 ± 0.11efg	73.28 ± 3.92abcde	57.93 ± 2.92bcde	2.28 ± 0.06efgh	11.67 ± 0.44dfgh	135.78 ± 0.97ghij
12.	Cymbopogon martinii	55.79 ± 4.46gh	74.79 ± 6.49abcde	57.58 ± 0.41cde	1.77 ± 0.12i	11.95 ± 0.60cdfg	107.51 ± 6.94k
13.	Cynodon dactylon	49.38 ± 1.73hi	66.95 ± 1.66cde	60.52 ± 4.58abcde	2.13 ± 0.07fghi	10.50 ± 0.73ghi	115.97 ± 7.81jk
14.	Cyperus rotundus	60.35 ± 0.95defg	73.89 ± 3.60abcde	64.06 ± 1.68abcd	2.29 ± 0.03efgh	11.78 ± 0.34dfgh	137.82 ± 0.49fghij
15.	Dichanthium aristatum	51.74 ± 3.33gh	67.52 ± 1.67cde	61.91 ± 1.28abcde	2.27 ± 0.09fgh	10.60 ± 0.28ghi	124.60 ± 5.80hijk
16.	Digitaria ciliaris	66.56 ± 0.18cdef	78.97 ± 0.36abc	58.17 ± 5.11abcde	2.13 ± 0.01fghi	12.72 ± 0.36abcdf	136.80 ± 5.94ghij
17.	Digitaria longifolia	77.30 ± 0.89ab	87.26 ± 4.66	60.35 ± 3.06abcde	2.15 ± 0.15fghi	14.25 ± 1.11a	152.68 ± 9.15defg
18.	Digitaria sanguinalis	78.53 ± 5.30a	86.11 ± 7.44a	58.85 ± 0.76abcde	2.06 ± 0.04fghi	14.04 ± 0.08a	144.00 ± 10.05efghi
19.	Echinochloa colona	73.91 ± 0.73abc	84.53 ± 2.83ab	61.22 ± 0.20abcde	2.36 ± 0.13defg	13.75 ± 0.78abc	162.20 ± 10.34cde
20.	Enteropogon monostachyos	53.02 ± 2.58gh	73.06 ± 1.63abcde	65.29 ± 2.86abc	2.85 ± 0.14abc	11.63 ± 0.46dfgh	169.06 ± 9.24bcd
21.	Eragrostiella bifaria	72.46 ± 4.55abc	82.02 ± 4.25ab	55.19 ± 0.66de	2.06 ± 0.08fghi	13.28 ± 0.52abcd	137.17 ± 1.60fghij
22.	Eragrostis cilianensis	73.68 ± 2.20abc	83.55 ± 2.88ab	56.27 ± 1.37cde	1.99 ± 0.03ghi	13.57 ± 0.17abc	135.50 ± 5.12ghij
23.	Eremochloa ophiuroides	72.21 ± 5.46abc	81.84 ± 2.41ab	61.99 ± 0.73abcde	2.67 ± 0.05bcde	13.25 ± 0.11abcd	177.86 ± 8.48abc
24.	Heteropogon contortus	42.05 ± 1.92i	64.34 ± 0.94de	65.44 ± 1.35abc	2.91 ± 0.25ab	10.01 ± 0.19hi	152.25 ± 11.50defg
25.	Hyparrhenia hirta	55.45 ± 4.80gh	73.97 ± 2.15abcde	62.52 ± 2.02abcde	2.04 ± 0.18ghi	11.79 ± 0.48dfgh	122.44 ± 2.50ijk
26.	Kyllinga brevifolia	79.13 ± 2.28	86.52 ± 5.95a	58.71 ± 1.98abcde	2.71 ± 0.18bcd	14.12 ± 0.53a	190.50 ± 11.49ab
27.	Melinis repens	60.98 ± 4.83defg	76.51 ± 5.72abcd	62.52 ± 5.57abcde	1.90 ± 0.15hi	12.27 ± 0.67bcdfg	118.26 ± 6.50jk
28.	Oplismenus burmannii	59.95 ± 4.37defg	74.87 ± 6.25abcde	68.04 ± 5.62a	3.17 ± 0.01a	11.96 ± 0.64cdfg	192.77 ± 4.11a
29.	Perotis indica	75.92 ± 2.48abc	85.88 ± 7.58ab	64.77 ± 3.86abcd	2.85 ± 0.23abc	14.00 ± 0.44a	198.83 ± 7.73a
30.	Themeda triandra	41.71 ± 1.68i	62.21 ± 5.60e	67.98 ± 4.38ab	2.83 ± 0.09abc	9.62 ± 0.74i	143.08 ± 3.11efghi
	SEM	2.45	3.47	2.56	0.10	0.49	5.82

a All values are represented on a dry matter basis; NFE: nitrogen free extract; TDN: total digestible nutrient; DDM: digestible dry matter; DMI: dry matter intake; ME: metabolizable energy; RFQ: relative forage quality; b According to the Tukey test, mean values with different superscript (abcdefghijkl) within a column are significantly different (p < 0.05). The data are expressed as mean±SD.; b Units of NFE, TDN, DMI and DDM are expressed in %. c Units of ME are represented as MJ/Kg DM.

4. Discussion

Grasses were the most preferred feed resource by elephants in the study area, most prominently during the rainy season [4]. Dry matter (DM) is the actual amount of feed material excluding water, volatile acid and bases. The DM content varies according to the plant species, parts of the plant and its maturity during various growing conditions such as thesoil and environment. This can be attributed to the fact that the grass grows naturally in forest areas with adverse climatic conditions. This is in accordance with the findings of Khanum [17], who reported that the DM content of salt tolerant grasses varied from 31.30% (Leptochloa fusca) to 56.10% (Cynodon dactylon). The average ash content of the samples was 4.27%. This result is consistent with the results reported by Hamid et al. [18], who stated that the values of Cenchrus ciliaris were between the range of 8.98% and 9.14%. The CP values of the grass fodder species were observed to be above the critical value of 7.5% which is reported to be required for proper digestion (Figure 3). This was in accordance with the findings of Faji et al., Gate et al. and Abebe et al. [19,20,21],where the CP values were obtained in the range of 5.04% (Desho grass) to 6.98% (Setaria sphacelata), 6.13% to 9.63% (Baja × Napier hybrid) and 7.24% (Cenchrus ciliaris) to 8.90% (Chrysopogon aucheri). Conversely, it was in contrast with the findings of Adebayo et al. [22],who reported thatthe values of CP were from 9.49% to 25.86% in Guinea grass.

Figure 3

Crude protein content of native grass fodder species.

The study also revealed that the crude fibre content was found in the range from 10.67 ± 0.78% to 34.63 ± 2.95%. This might be attributed to the site quality, season, plant species and their growth pattern. The range of the crude fibres in the grasses studied is in accordancewith the findings of Karbivska et al. and Khude and Al-Rowaily et al. [8,23,24], who reported that the crude fibre content varied from 29.00% (Lolium perenne) to 30.40% (Dactylis glomerata), 25.00% (Leptochola fusca) to 28.50% (Pennisetum purpureum), and 11.97% (Cyperus conglomeratus) to13.84% (Panicum turgidum) respectively. The. NDF content of all the grasses lies below the critical value of 60%. High NDF content in the fodder affects the voluntary feed intake and feed conversion efficiency. According to Singh and Oosting [25], if the roughage contains above 65% NDF, it is considered as poor quality feed. This supports the findings of Faji et al., Gate et al. and Megersa et al. [20,26,27], who reported that the ADF and NDF contents were in the range of 35.33% (Panicum aquatica) to 42.03% (Panicum coloratum) and 64.89% (Panicum aquatica) to 71.62% (Chloris gayana); 29.80% to 52.80% (Bajra x Naiper hybrid) and 61.40% to 77.60% (Bajra x Naiper hybrid); and 42.33% (Pennisetum unssetm) to 54.99% (Pennisetum sp.) and 72.45% (Eustachys paspaloidsi), respectively (Figure 4).

Figure 4

Crude fibre (CF), acid detergent fibre (ADF) and neutral detergent fibre (NDF) per cent in native grass fodder species.

The average TDN content of grass fodder was 77.45% (Table 3). A similar result was reported by Hamid et al. [18], who reported that the values were in the range of 53.14% to 63.65% TDN, which provides an assessment of the energy content of the feed. The larger the value of TDN, the more energy is condensed within feedstuff. The study was in accordancewith those of Zewdu, Khude, and Bamikole and Ikhatua [8,28,29], where the values were found in the range of 8.61 MJ/Kg DM to 9.77 MJ/Kg DM (Pennisetum purpureum); 6.36 MJ/Kg DM (Cynodon dactylon) to 7.29 MJ/Kg DM (Sporobolus arabicus); and 8.77 MJ/Kg DM (Pannicum maximum). Among the forage quality parameters, RFQ is very essential because forage quality index is used to allocate forages to the herbivores with the given levels of expected performance [30]. DDM denotes the total digestibility of the feed, whereas DMI denotes the amount of feed an animal consumes as a percentage of its body weight and is calculated from its NDF percentage. The maximum RFQ was recorded in Perotis indica, followed by Oplismenus burmannii. This might be due to the lower ADF and NDF content in the above grass species than in other grass species, because the RFQ is derived from ADF and NDF [31] (Figure 5). The results were indirectly proportional to the ADF and NDF content (Figure 6). The study was in agreement with the findings of Faji et al. [26],who recorded the RFQ values in the range between 115.07% (Chloris gyana) and 122.92% (Urochloa decumbens).

Figure 5

Relative forage quality of native grass fodder species.

Figure 6

Relationship between detergent fibres and relative feed quality.

5. Conclusions

Wild grass fodder species plays a vital role in improving herbivore productivity in natural forests, and it has potentially good protein supplements, particularly during the critical periods of the year when the quantity and quality of herbage are limited. The major limiting factor for an elephant’s biorhythm is feed, both in terms of quantity as well as quality. To curb the problem of feed shortage, the incorporation of wild grass fodder species could be regarded as a one-stop solution in habitat management. The unavailability of feed sources is one of the most significant concerns for elephant conservation in the Western Ghats, and can be solved through the rehabilitation of elephant corridors and habitat areas. In order to rehabilitate these elephant corridors, authenticated and consistent information on the nutritional value of native fodder grass species is required. This study is highly significant for being the pioneer research on the nutritional evaluation of native grass fodder species in the Western Ghats, which can form the backbone for management plans to enrich the habitats of elephant corridors. The identified nutrient rich grass fodder species, viz., Cynodon dactylon, Dichanthium aristatum, Heteropogon contortus, Oplismenus burmannii and Themeda triandra, are highly recommended for fodder bank development in corridors and fringe areas to cater to the needs of the megaherbivore and its niche areas.