Comparing Feed Intake, Digestibility, Growth and Economic Gain of Horro and Washera Sheep Breeds Fed Wheat Straw Basal Diet Supplemented With Effective Microorganisms Treated Wheat Straw and Concentrate Mixture

ABSTRACT

Background and Objectives

An experiment was conducted to compare Horro and Washera sheep in terms of feed intake, digestibility, body weight gain and economic feasibility fed untreated wheat straw (UTWS) a basal diet and supplemented with an effective microorganism‐treated wheat straw (EMTWS) and concentrate mixture (CM).

Materials and Methods

A total of 10 from each sheep breeds and 2 supplement amounts of EMTWS, supplemented at 10% (A1) and 15% (A2) of the total dry matter intake (TDMI), were arranged in a 2 × 2 factorial treatment arrangement in a completely randomized block design. The sheep of each breed were blocked on the basis of their initial body weights into five blocks of four animals in a block (two animals from each sheep breed), and treatment feeds were randomly allocated within a block during the 100 experimental days. Daily feed intake and body weight at the 10‐day interval were recorded, and data were analysed using general linear model procedures (PROC GLM) of SAS software program.

Results

The crude protein (CP) content of EMTWS showed only a 1% increment over UTWS, whereas its neutral detergent fibre (NDF) and acid detergent fibre (ADF) values showed a 10% reduction over UTWS. Washera sheep consumed 40 g more TDM over Horro sheep. Sheep fed the A2 supplement consumed 86 g more (p < 0.0001) TDM over A1‐fed sheep. Consequently, Washera sheep and sheep fed‐A2 gained 1 and 3 kg of additional body weight by growing 11 g/day and 33 g over Horro sheep and those sheep fed‐A1, respectively. Sheep fed‐A2 and Washera sheep gave better economic returns than A1‐fed sheep and Horro sheep, respectively.

Conclusion

Therefore, from the results of the study, it could be suggested that rearing Washera sheep by supplementing 15% EMTWS along with a CM can be recommended for smallholder farmers.

After 100 daysof feeding, this study showed that effective microorganism‐treated wheat strawfeeding at 15% TDMI (A2) vs. 10% TDMI (A1) improved body weight gain andresulted in 279 more net returns over A1‐fed sheep. The findings also revealedthat Washera sheepgained higher body weight and economic gain than Horro sheep.

Abbreviations

ADF

acid detergent fibre

ADL

acid detergent lignin

AEBWG

average every day body weight growth

BW

body weight

BWC

body weight change

CP

crude protein

DM

dry matter

DMI

dry matter intake

DOM

digestible organic matter

EM

effective microbes

EMROSA

Effective Microorganisms Research Organization of South Africa

EMTWS

effective microorganism treated wheat straw

FBWCE

feed‐to‐body weight conversion efficiency

1. Introduction

Livestock farming is a vital economic activity in many parts of the world, producing both food and non‐food products. Sheep are the primary livestock species and an important component of tropical and temperate agricultural systems. They are excellent for extensive to highly mechanized production systems and are found in all agro‐ecologies. Aside from the quantitative outputs of numerous items, they are significant for job creation, income growth, capital formation, product diversification, crop failure insurance and human nourishment (Wodajoa et al. 2020).

Ethiopia has an estimated 38 million sheep (CSA 2022), with around 9 breeds scattered over the country's agro‐ecology (Solomon et al. 2007). Sheep are primarily raised for meat; wool and milk are of minor importance (Helen et al. 2013; Legesse et al. 2008; Tesfaye et al. 2010). The sheep breeds are adapted to diverse local production concentrates and are able to thrive with minimum inputs. Sheep grow slowly due to a variety of pressures. Among the pressures, feed scarcity is the most significant factor that causes sheep breeds to be under productive (Ayele and Urge 2019).

Small ruminants, notably sheep, in Ethiopia rely on crop residue and grazing on natural grazing lands as their primary nutrition source throughout the year, similar to other crop‐livestock mixed farming systems in tropical nations. The share of natural pasture grazing as a food source is decreasing year after year as cropping expands into grazing areas. These processes increase the amount of crop residue produced from year to year. Crop residue accounts for around 32% of livestock feed (CSA 2022), but it can reach 80% in some parts of Ethiopia during the dry season (Adugna 2007).

Crop residues have low nutritive value, high fibre content and low digestibility due to the close association of carbohydrates with lignin (Van Soest 1994). They are also low in crude protein (CP) (<7%), metabolizable energy (<7.5 MJ/kg dry matter [DM]), vitamins and minerals. As a result, animals raised solely on crop residue lose significant body weight (BW) (Ayele et al. 2022). Therefore, technical solutions that improve the nutritional content and digestibility of this bulk feed are critical for increasing animal productivity in locations where a mixed crop‐livestock production system is undertaken.

One of the technology choices for improving nutritional content while reducing fibre content in crop residue is to treat it with effective microorganisms. Effective microbe (EM) is a solution containing different kinds of coexisting microorganisms chosen from thousands of microbial species (EMROSA 2006). EM is added to feeds to improve fibrous feed consumption by successful colonization and breakdown, hence preserving the proper microbial balance in the digestive system. The addition of effective microorganism solution to concentrate feeds had no significant effect on raising the CP content of treatment feeds (Chernet 2012). On the other hand, Worku et al. (2016) and Tadessu et al. (2019) reported the presence of significant differences in CP content and in intake, digestibility and weight gain when effective microorganism‐treated roughage feeds are fed in different levels to different livestock species.

Genetic heterogeneity exists across indigenous sheep breeds of Ethiopia in terms of productivity, survival and reproductive performance (Ayele and Urge 2019; Solomon et al. 2007). There is also variance in feed intake, digestibility and feed conversion ability into weight (Ayele et al. 2017; Temesgen et al. 2020; Tsegay et al. 2013). These are unexplored opportunities to choose and employ sheep breeds that are compatible with the feed available in the area. Feed costs account for 70%–80% of the total cost of production in every animal farm; lowering feed costs can significantly improve farm profitability. Thus, comparing and deciding that the sheep breeds best utilize the available feed resource is of great importance to reduce production costs. Thus, this study was designed to test following specific objectives:

1. To evaluate the differences in feed intake, digestibility and BW change of Horro and Washera sheep breeds fed wheat straw basal diet supplemented with different levels of EM‐treated wheat straw and concentrate mixture (CM).

2. To assesses the economic feasibility of the feeding regime using the two sheep breeds.

2. Materials and Methods

2.1. Experimental Site Description

The study area is located at 10°18′0″ N latitude and 37°28'0″ E longitude in global position, and it lies within an altitude range of 1774–2510 meters above sea level and predominantly consists of mid‐altitude agro‐ecology. The average annual minimum and maximum temperatures are 21°C and 27°C, respectively, and the annual rainfall of the area is 1500 mm.

2.2. Experimental Sheep Description Their Handling and Data Collection

Two indigenous sheep breeds of Ethiopia, such as Horro and Washera, were used for the study. The two breeds are well‐known, prolific, fast‐growing and fat‐tailed‐haired sheep (Solomon et al. 2007), and mainly they are kept for meat production.

Twenty intact yearlings from the 2 breeds, 10 from each breed, were purchased from the local market for the experiment. The animals bought were similar in size, body condition, age and good health. To estimate the age of the animal, incisor teeth were observed, and information was asked from the holder. The animals were held in quarantine for 21 days and observed for any health problems. During this time, animals were treated with a broad‐spectrum antihelminthics, (albendazole) against internal parasites and sprayed with acaricide (diazinon) against external parasites. They were vaccinated against anthrax and sheeppox by consulting the veterinarian. Following the quarantine period, the initial BW of all animals was measured after overnight fasting with feed and water. Animals were placed in individual pens equipped with a water bucket and a feeding through, and they were handled following the international guiding principles listed by Council for International Organizations of Medical Sciences and International Council for Laboratory Animal Science (2012).

After the completion of the quarantine period, the sheep were accustomed to the experimental diets and the house environment for about 15 days before the commencement of the actual experiment. Each sheep was identified with a neck collar. The animals of each breed were blocked on the basis of their initial BWs into five blocks of four animals in a block (two animals from each sheep breed), and treatment feeds were randomly allocated within a block. During this time, the randomly allocated treatment diet was introduced gradually over the 2 weeks of the acclimation period in such a way that the total daily offer was reached at the end of the acclimation period.

Following the 15‐day adaption phase, a digestibility study lasting 10 days was done. For this aim, all experimental animals were tethered with faecal collection bags and let to acclimate to the bags and the overall management conditions for 3 days before collecting faeces for 7 days. Every morning, feed offered and refused were recorded daily, and samples from feed offered and refusals from each animal were taken daily to make a composite sample per treatment. The total daily faecal output per animal was weighed daily before the morning meal was served. Then, representative faecal samples of 10% from each animal were collected daily and bulked across the study period to create a weekly composite faecal sample for each animal, which was stored in the refrigerator at −20°C. At the end of the collection time, the total collected samples from each animal were thawed and well mixed; a 20% of it was taken for chemical analysis. Faecal samples were partially dried in a forced‐dry oven at 55°C for 72 h. The partially dried faeces samples were crushed to pass through a 1 mm screen and stored in an airtight bag pending chemical analysis. The apparent digestibility (AD) of DM, organic matter (OM), CP, neutral detergent fibre (NDF) and acid detergent fibre (ADF) was determined by the following equations (McDonald et al. 2010):

$$\begin{array}{ccc}& & \mathrm{ADMD}\mathrm{or}\mathrm{nutrient}\mathrm{digestibility}\left(\%\right)=\hfill \\ & & \frac{\mathrm{DM}\mathrm{or}\mathrm{nutrient}\mathrm{intake}-\mathrm{faecal}\mathrm{DM}\mathrm{or}\mathrm{nurient}}{\mathrm{DM}\mathrm{or}\mathrm{nutrient}\mathrm{intakes}}\times 100\hfill \end{array}$$

where ADMD is the apparent dry matter digestibility.

The feeding trial lasted for 90 days following digestibility trial. Daily feed was offered to the experimental animals, and the corresponding refusals for each animal were measured and recorded during the experimental period to determine daily feed intake. Feed was weighed and offered each morning after weighing and discarding the feed refusals of the previous day. Each feed sample from the offer was taken per batch and pooled to have a single sample for each feed. Daily grab samples of feed refusals were collected and weighted for each animal, then pooled per treatment, and sub samples were taken for chemical analysis. Daily feed intake was calculated on DM basis as the difference between the amounts of feed offered and refused. The metabolize energy MJ/day intake was estimated from digestible organic matter intake (DOMI) values by using the equation of AFRC (1993) as ME (MJ/day) = 0.0157 × DOMI g/kg DM.

BW of each animal was measured at the beginning of the feeding trial and every 10‐day intervals thereafter throughout the 90 days feeding period after overnight feed and water withdrawal by using suspended weighing scale with sensitivity of 100 g. AEBWG was calculated as the difference between final live weight and initial live weight divided by the 90 days of experimental period. BW change was calculated as the difference between final and initial live weights. Feed‐to‐body weight conversion efficiency (FBWCE) of experimental animals was determined by dividing AEBWG to the amount of daily feed eaten.

2.3. Experimental Feeds Collection and Preparation

Wheat straw (base diet) was acquired from a nearby farmer's farm and chopped into 4–5 cm lengths to facilitate consumption and reduce wastage. It was kept in a shed to preserve its quality. A sufficient quantity of inactivated EM solution (EM‐1) packed in plastic bottles was acquired from animal feed vendors in the study area. The EM‐1 solution mostly consists of photosynthetic bacteria, yeast and lactic acid bacteria. To activate the EM‐1 solution, molasses was added in equal parts. The EM with molasses combination solution was then diluted with chlorine‐free water at a ratio of 1:18 (1 L of EM with molasses mixture combined with 18 L of water), resulting in the EM solution. The EM solution was stirred and stored in a well‐covered plastic barrel (300 capacities) for 7 days to activate the EM (Begna et al. 2023; Tibebu et al. 2018). Thereafter, the EM solution was progressively poured onto the wheat straw in small amounts and properly mixed by hand until it was just wet enough that no moisture leaked out when squeezed. To reach the optimal moisture level, 1 L of EM solution was poured over 3 kg of wheat straw. The saturated wheat straw was then packed into an airtight sack, removing as much air as possible before sealing it. The packed sack was placed in a warm, dark room to ferment for 21 days. The treated (fermented) wheat straw was then given as a supplement twice a day, at 0800 and 1600, in equal amounts. In addition, wheat bran (WB) and noug seed cake (NSC) were purchased from nearby flour and oil extraction factory, respectively, to prepare a concentration mixture. The CM was prepared by combining WB and NSC at a ratio of 2:1 in that order, and it was given 150 g/day/sheep at one time to all sheep. All animals were given free access to water and salt licks.

2.4. Design and Treatments

The animals of each breed were blocked on the basis of their initial BWs into five blocks of four animals in a block (two animals from each sheep breed), and treatment feeds were randomly allocated within a block. The experiment used a 2 × 2 factorial treatment arrangement (two supplement amount and two sheep breeds) with a completely randomized block design. The two supplement amounts were 10% and 15% EM‐treated wheat straw of total DM intake (TDMI) (TDMI is the intake of basal diet +150 g/day concentrate supplement), denoted as amount 1 (A1) and amount 2 (A2), respectively. All sheep were given a 150 g/day concentrate supplement. Chopped wheat straw (untreated) as a basal diet was given ad libitum at a refusal rate of around 25%, which was adjusted every 5 days.

2.5. Profitability Analysis

The economic advantages of supplementing with EM‐treated wheat straw for the two sheep breeds were calculated using the Upton (1979) approach. The purchase and selling prices of experimental sheep, as well as the total quantity and purchasing prices of basal and supplement feed, were recorded. However, other costs, like labour, housing and veterinary service, were common for all treatments and were not considered for calculation. The analysis involved the calculation of the variable costs of experimental sheep, feeds and benefits gained from the result. In the analysis, the total return (TR) was determined by calculating the difference between selling and purchasing price of sheep in each treatment. The cost of feeds was computed by multiplying the actual feed intake for the whole feeding period with the prevailing prices. The partial budget measures profit or losses, which are the net benefits or differences between gains and losses for the proposed change, and includes calculating net return (NR), that is, the amount of money left when total variable costs (TVC) are subtracted from the TR.

2.6. Experimental Feeds and Faecal Sample Nutrient Analysis

Representative partially dried samples of feed offers, refusals and faecal samples collected during the experimental period were milled to pass through a 1 mm sieve screen. The DM, CP and ash were determined in accordance with AOAC methods (1990). CP was calculated as N × 6.25. The NDF, ADF and acid detergent lignin (ADL) were determined using Van Soest and Robertson's (1985) technique. OM was estimated by subtracting ash from 100.

2.7. Data Analysis

All collected data were subjected to analysis of variance (ANOVA) using SAS's general linear model procedures (PROC GLM) (2008) version 9.2. If the F test results show a significant difference, the treatment means of all parameters were separated using the least significant difference (LSD) test. When the interaction effects were statistically significant at p < 0.05, the interaction least‐squares means were displayed and analysed. In the absence of interaction, the least‐squares means for the main components were presented and discussed.

The model for data analysis was as follows:

$$Y_{ijk}=\mu +{\mathrm{s}a}_i+r_j+b_k+{\left(\mathrm{s}a\times b\right)}_{ik}+e_{ijk}$$

where Y_ijk is the response variable, μ is the overall mean, sa _i is the ith effect of supplement amount, r_j is the jth block effect, b_k is the breed effect, (sa × b) _ik is the interaction between supplement amount and breed, and e_ijk is the random error.

3. Results

3.1. Nutrient Content of Feeds

The nutrient content of the feeds used in this trial is presented in Table 1. The CP content of wheat straw treated with EM solution showed only a 1% increment over UTWS, whereas its NDF and ADF values showed about a 10% reduction over UTWS. On the other hand, the concentrate mix contained six times and seven times higher CP over the treated and untreated wheat straw, respectively, and it contained around three times lower NDF and ADF content over the treated and untreated wheat straw (Table 1).

TABLE 1.

Nutrient content of experimental feeds as percentage of dry matter.

Feeds	DM	OM	CP	NDF	ADF	ADL
Wheat straw (untreated)	97	89.75	3	69.92	61.70	11.68
Wheat straw EM treated	96	89.7	4.08	60.00	51.06	9.71
Noug seed cake	93.00	82.58	29.41	31.52	16.24	3.3
Wheat bran	92	85.38	15.57	38.45	25.68	4.55
Concentrate mix	92.3	84.45	20.1	36.1	22.55	4.13

Note: Concentrate mix = wheat bran and noug seed cake in 2:1 ratio in that order.

Abbreviations: ADF, acid detergent fibre; ADL, acid detergent lignin; CP, crude protein; EM, effective microbes; DM, dry matter; NDF, neutral detergent fibre; OM, organic matter.

3.2. Intakes

Intakes of DM and nutrients by sheep breeds are presented in Table 2. There was a statistical difference in DM and nutrient intakes between sheep breeds and supplement amounts. The effect of sheep breed on TDMI expressed as a percentage of BW was not apparent (p > 0.05). However, the effect of supplement amounts on TDMI expressed as a percentage of BW was significant (p < 0.0001). The breed‐by‐supplement amount interaction effect was not significant (p > 0.05) in all intake values. Sheep fed the A2 supplement consumed 44, 42 and 86 g more UTWS, effective microorganism‐treated wheat straw (EMTWS) and TDM, respectively, over A1‐fed sheep. Washera sheep consumed 36 and 40 g more UTWS and TDM than Horro sheep. Moreover, Wahera sheep consumed more EMTWS than Horro sheep. OM, CP, ME, NDF and ADF intakes are the results of total DM intake, and hence, Washera sheep had higher intake than Horro sheep in these parameters. Likewise, sheep fed A2 had higher intakes of OM, CP, ME, NDF and ADF than sheep fed A1.

TABLE 2.

Average daily feed intake of Horro and Washera sheep fed wheat straw supplemented with effective Microbes treated wheat straw at different proportions and concentrate mix.

	Breed supplement amount p value
Intakes	Horro	Washera	SEM	A1	A2	SEM	S	Breed	Breed*S
UTWS (g/d)	500b	536a	1.44	496b	540a	1.44	<0.0001	<0.0001	0.077
EMTWS (g/d)	87b	91a	0.17	68b	110a	0.17	<0.0001	<0.0001	0.2511
Concentrate	150	150		150	150
Total DM (g/day)	737b	777a	1.6	714b	800a	1.57	<0.0001	<0.0001	0.0810
DM (%BW)	4.3a	4.3a	0.33	4.46a	4.2b	0.24	<0.0001	0.0811	0.9317
ME (MJ/day)	7.7b	8.5a	0.21	7.4b	8.9a	0.21	<0.005	0.0140	0.9090
Total OM	654b	688a	1.42	631b	708a	1.42	<0.0001	<0.0001	0.0618
Total CP	49b	50a	0.04	48b	51a	0.04	<0.0001	<0.0001	0.1274
Total NDF	455b	482a	1.09	410	492	1.09	<0.0001	<0.0001	0.35
Total ADF	385b	405a	0.96	373b	422a	0.96	<0.0001	<0.0001	0.1439

Note: Concentrate mix = wheat bran and noug seed cake 2:1 ratio: Al = amount 1 = 10% EMTWS of total dry matter intake; A2 = amount 2 = 15% EMTWS of total dry matter intake. Means with different letters (a, b) in a row are significantly different at p < 0.05.

Abbreviations: Al, amount 1; A2, amount 2; ADF, acid detergent fibre; BW, body weight; CM, concentrate mix; CP, crude protein; DM, dry matter; EMTWS, effective microbes treated wheat straw NDF, neutral detergent fibre; OM, organic matter; S, supplement; SEM, standard error of mean; UTWS, untreated wheat straw.

3.3. Digestibility

The AD of DM and nutrients for the experimental animals is given in Table 3. The AD of OM, CP and NDF was affected (p < 0.0001) by genotype and amount of supplement, but their interaction failed to be significant. For other AD parameters, such as DM and ADF, significant interaction effects were evidenced between genotype and supplement amount.

TABLE 3.

Apparent digestibility of dry matter and digestible nutrient intakes of Washera and Horro sheep fed wheat straw and supplemented with effective microbes treated wheat straw at different levels and concentrate supplements.

	Breed			SA				p value
Parameters	Horro	Washera	SEM	A1	A2	SEM	S	Breed	Breed × S
DM							<0.0001	<0.0001	0.0004
A1	68d	73c
A2	75b	79a
OM	75b	79a	0.11	75b	80a	0.11	<0.0001	<0.0001	0.1177
CP	90b	92a	0.03	90b	92a	0.03	<0.0001	<0.0001	0.8350
NDF	72b	77a	0.13	72b	77a	0.133	<0.0001	<0.0001	0.3002
ADF							<0.0001	<0.0001	<0.0001
A1	67c	73c
A2	71b	79a
Digestible intakes (g/day)
TDDM	517b	617a	1.87	538b	635a	1.87	<0.0001	<0.0001	0.1332
TDOM	490b	543a	1.64	473b	566a	1.64	<0.0001	<0.0001	0.3288
TDCP	44b	46a	0.05	43b	47a	005	<0.0001	<0.0001	0.5006
TDNDF	327b	371a	1.24	295c	378a	1.24	<0.0001	<0.0001	0.1008
TDADF							<0.0001	<0.0001	<0.0001
A1	235d	279c
A2	285b	339a

Note: Means with different letters (a, b, c, d) in a row are significantly different (p < 0.05). A1 = 10% EMTWS (10% of 150 g/d CM + basal duet intake g/d), A2 = 15% EMTWS (15% of 150 g/d CM + basal intake g/d).

Abbreviations: A1, amount 1; A2, amount 2; ADF, acid detergent fibre; CM, concentrate mix; CP, crude protein; DM, dry matter; EMTWS, effective microbes treated wheat straw; NDF, neutral detergent fibre; OM, organic matter; S, supplement; SA, supplement amount; SEM, standard error of mean; TCPD, total crude protein digestibility; TDADFI, total digestible acid detergent fibre intake; TDCPI, total digestible crude protein intake; TDMD, total dry matter digestibility; TDNDFI, total digestible neutral detergent fibre intake; TDOMI, total digestible organic matter intake; TOMD, total organic matter digestibility.

The AD of OM, CP and NDF was higher (p < 0.0001) for Washera sheep than for Horro sheep. The AD of OM, CP and NDF was higher for sheep fed A2 than A1‐fed sheep. DM and ADF digestibility were higher for Wahera sheep fed A2 than for Horro sheep supplemented with the same amount. Digestible DM and nutrient intakes are functions of DM and nutrient intakes and their digestibility, and hence, Washera sheep exhibited higher digestible DM and nutrient intakes than Horro sheep. Similarly, sheep fed A2 had higher digestible DM and nutrient intakes than their counterparts fed A1.

3.4. Growth and Feed‐to‐BW Conversion Efficiency

The effect of sheep breed and supplement amount on final BW, BW change, AEBWG and FBCE was apparent (p < 0.05). However, the breed‐by‐supplement interaction effect failed to be significant on the parameters mentioned (Table 4). Sheep fed A2 gained 3 kg of additional BW at the end of the feeding trial over those sheep supplemented with A1 by growing 33 g more per day over A1 fed sheep. FBWCE was higher for sheep fed A2 than their A1 counterparts. Sheep fed A2 consumed 14.4 g of feed to gain 1 g of BW, whereas those sheep fed A1 required 16 g of feed to gain 1 g of BW. Washera sheep gained 1 kg extra BW over Horro sheep by growing on average 11 g/day grater over Horro sheep.

TABLE 4.

Growth and feed‐to‐body weight conversion efficiency of Horro and Washera sheep fed wheat straw supplemented with effective microbes treated wheat straw at different levels and concentrate mixtures.

	Breed			SA				p value
Parameters	Horro	Washera	SEM	A1	A2	SEM	S	Breed	Breed*S
IBW (kg)	14	14	1.66	14	14	1.66	0.1456	0.7333	0.7530
FBW (kg)	17b	18a	0.60	16b	19a	0.60	0.0215	0.0434	0.8451
BWC (kg)	3b	4a	0.16	2b	5a	0.16	0.0006	<0.0001	0.7720
AEBWG(g/d)	33.33b	44.44a	1.85	22.22b	55.55a	1.85	0.0006	<0.0001	0.7720
FBWCE	0.045b	0.057a	0.002	0.062b	0.069a	0.002	0.0063	0.0001	0.9317

Note: means with different letters (a, b) in a row are significantly different at p < 0.05; A1 = %. EMTWS (15% of 150 g/d CM + basal intake g/d). A1 = 10% EMTWS (10% of 150 g/d CM + basal duet intake g/d), A2 = 15%.

Abbreviations: A1, amount 1; A2, amount 2; AEBWG, average every day body weight growth; BWC, body weight change; CM, concentrate mix; EMTWS, effective microbes treated wheat straw; FBW, final body weight; FBWCE, feed‐to‐body weight conversion efficiency; IBW, initial body weight; S, supplement; SA, supplement amount.

3.5. Profitability

The profitability analysis result of Washera and Horro sheep fed a wheat straw basal diet supplemented with an effective microorganism‐treated wheat straw and CM is presented in Table 5. The result of this study indicated that a higher NR (302.9 Ethiopian birr [ETB]/sheep) was obtained from the sheep supplemented with 15% EM‐treated wheat straw (A2) and from Washera sheep (225 birr/head).

TABLE 5.

Partial budget analysis of Horro and Washera sheep fed Wheat straw and supplemented Effective microbes treated wheat straw at different amounts and concentrate mixtures.

	Breed		SA
Variables	Horro	Washera	A1	A2
Sheep purchasing price (ETB/head)	1400	1500	1400	1425
Sheep selling price (ETB/head)	1925	2150	1800	2200
Wheat straw consumed (basal) (kg/head)	45	48	45	48.6
Total EM and molasses solution treated wheat straw consumed (kg/head)	7.83	8	6	9.9
Total NSC consumed (kg/head)	4.5	4.5	4.5	4.5
Total wheat bran consumed (kg/head)	9	9	9	9
Feed cost
Cost for wheat straw/kg (ETB)	2.50	2.50	2.50	2.50
Total cost for wheat straw (ETB/head)	112.5	120	110	121.5
Cost for NSC/kg (ETB)	12	12	12	12
Wheat bran/kg (ETB)	7	7	7	7
Total cost for NSC/(ETB/head)	54	54	54	54
Total cost for wheat bran/(ETB/head)	63	63	63	63
Cost for EM/litter (ETB)	15	15	15	15
Cost for molasses/litter (ETB)	7	7	7	7
Total cost for EM‐treated wheat straw (ETB/head)	191.83	196	147	292.05
Total feed cost (ETB/head)	421.335	425.5	376.5	472.05
Total return (ETB/head)	525	650	400	775
Net return (ETB/head)	103.667	225	23.5	302.95

Note: A1 = 10% EMTWS of the total dry matter intake; A2 = 15% EMTWS of the total dry matter intake.

Abbreviations: A1, amount 1; A2, amount 2; CM, concentrate mix; EM, effective microbe; EMTWS, effective microbes treated wheat straw; ETB, Ethiopian birr; NSC, noug seed cake; SA, supplement amount.

4. Discussion

4.1. Nutrient Content of Feeds

The CP contents of both treated and untreated wheat straw were much lower than the minimum CP (7.5%) requirement of ruminant animals to satisfy their maintenance requirement (Van Soest 1994), indicating EM brought little improvement of the CP content of low‐quality straw, and it suggests other treatments or combinations of treatments to improve the CP value of crop residue. The 1% CP improvement in wheat straw treated with EM solution is slightly higher than the values of 0.42% and 0.4% CP increments reported by Getu et al. (2016) and Begna et al. (2023) for EM‐treated wheat straw and rice husks, respectively. This, however, was lower than the 4.4% CP increment of EM‐treated grass hay over the untreated grass hay (Tadessu et al. 2019). The variation in CP improvement of roughage feeds among studies might arise from nitrogen loss during the drying process and pending feed until chemical analysis.

According to the review work of Jalc (2002), the use of EM reduces the fibre content of the roughage feed by metabolizing lignocelluloses by selective de‐lignifications. In the current study, a 10% NDF and ADF reduction may be the result of the above action. In the present study, the NDF and ADF contents of untreated wheat straw were higher than the limit (65%) that affects the DM intake and digestibility of ruminant animals. However, thanks to EM treatment, the NDF and ADF contents of wheat straw were reduced by 10%, and this was below the limit that affects the intake and digestibility of roughage feed by ruminant animals. In‐line with the current study, a 9.5% NDF and ADF reduction was recorded for EM‐treated rice husks (Begna et al. 2023). Moreover, comparable ADF (12%) but lower NDF (5.1%) reductions as compared to the current study were documented on EM‐treated wheat straw (Getu et al. 2016). However, this 10% reduction in NDF and ADF was lower than the 15% decrease recorded for grass hay treated with EM (Tadessu et al. 2019).

In this study, the CM had relatively higher CP and lower NDF and ADF contents than wheat straw (treated and untreated), indicating its paramount nutritional importance to supplement ruminants on poor‐quality roughages. As it is well noted, low‐quality forages ferment slowly and yield low levels of rumen ammonia, which does not promote an efficient digestion process, and as a result, voluntary intake of straw and hay is limited (McDonald et al. 2010; NRC 2000).

4.2. Intakes and Digestibility

The fact that sheep‐fed A2 supplements consumed more roughage and total DM and had greater digestibility than their A1‐fed counterparts is explained by the fact that A2 supplements provide relatively higher CP and metabolizable energy, which is important to increase the microbial population in the rumen to support optimum rumen activity, thereby improving the rate of degradation and feed intake (McDonald et al. 2010). The higher feed intake of A2‐fed sheep is also linked with the higher BW gain of sheep, so animals consume more food to compensate for the increased maintenance requirements (Forbes 2007; NRC 2000). In agreement with the current study, Ayele et al. (2017), Dereje et al. (2016) and Tsegay et al. (2013) recorded higher intake and digestibility of small ruminants on higher supplement levels than the lower ones.

According to different researchers, roughage feed intake by ruminant animals is dependent on reticulorumen volume (Fisher 2002; Forbes 2007; Kasahun 2000; Shashie et al. 2019), weight gain and the ability to digest feed (Ayele et al. 2017). In turn, these variations arise from the breed effect (Freetly et al. 2020). Hence, in the current study, the higher DM intake of Washera sheep than Horro sheep might be linked with these reasons.

However, there are inconsistent reports regarding the potential of Horro and Washera sheep in feed intake and digestibility (Assefu 2012; Ayele et al. 2017). Ayele et al. (2017) reported in their study that Horro sheep consumed more than Washera sheep when sheep were kept in two levels of concentrate supplement, whereas Assefu (2012) reported similar feed intake and digestibility between the two breeds when sheep were fed different proportions of roughage to concentrate ratio. Therefore, these conflicting results need more work to distinguish the potential breed in feed intake and utilization. Feed intake is the main factor in the utilization of fibrous feed by ruminant animals and is a major determinant of the energy intake and performance of an animal.

DM intake determines the amount of nutrients ingested by an animal. Hence, the reason for the higher OM, CP, ME, NDF and ADF intakes recorded in Washera sheep as well as in sheep fed A2 is the result of higher TDMI. Similar observations to the present study were reported by many researchers (Adugna et al. 2023; Ayele et al. 2022; Yimenu and Abebe 2023).

The increase in DM intake expressed as a percentage of BW in sheep fed A2 supplement is related to feed quality improvement. The higher the quality of feed supplied to the animal, the greater its consumption. One of the determinants of feed quality is the amount of protein available in the feed; thus, in the current study, the amount of protein was higher in sheep fed A2 and hence the added protein promotes the proliferation of rumen microorganisms, allowing for more efficient digestion of feed, resulting in high feed intake. In general, the overall DM intake as a percentage of BW in the current study fell within the ARC's recommended range of 2%–6% (ARC 1980).

4.3. Growth, Feed‐to‐BW Conversion Efficiency and Economic Gain

Sheep fed A2 gained 3 kg of additional BW at the end of the feeding trial over those sheep supplemented with A1 by growing 33 g more per day that is an attribute of higher CP and ME intake that allows more microbial population growth and therefore promotes digestion, making nutrients available to increase weight gain in sheep. The effect of supplement amount on body weight change (BWC) and AEBWG is in agreement with the findings of Tadessu et al. (2019), who reported that BWC and AEBWG of Washera sheep showed improvement when EM‐treated grass hay supplement increased from 5% to 10%. The current finding is also in‐line with that reported by Ayele et al. (2017) and Tsegay et al. (2013), who observed higher AEBWG from the groups consuming higher levels of the supplement than sheep in lower levels. Dereje et al. (2016) also recorded higher AEBWG in goats supplemented with 1.5% BW concentrate supplement than those consuming 1% BW.

AEBWG values in the current study were lower than the values (50–71 g/day) reported for Washera sheep fed different types of basal and supplement diets (Melese et al. 2014). On the other hand, a lower AEBWG value of 25–34 g/day was noted by Abebe et al. (2011) for Washera sheep fed urea‐treated rice straw basal diet supplemented with 200–400 g DM/day of NSC, WB and brewery dried grain mixture.

In the current study, Washera sheep gained 1 kg more BW than Horro sheep, which could be attributed to improved nutrient digestion and utilization. Several studies found a positive and substantial relationship between digestibility and growth (Fisher 2002; Fentie and Solomon 2008; Likawent et al. 2012; Teshager et al. 2022). Thus, the findings of this study suggest a potential variation in growth performance between the Horro and Washera breeds. The current experiment's results are consistent with Chipman's (2003) prior report comparing the growth performance of Washera, Menz and Horro sheep, which found that Washera sheep performed better under an enhanced feeding regime. But in contrast to the current as well as the previous studies, Ayele et al. (2017) reported that Horro sheep had heavier (p < 0.0001) final body weight (FBW), ADG and BWC than Washera and blackhead Ogaden breeds in a trial comparing three sheep breeds. The inconsistent results among studies on the growth potential of breeds might be due to the quality and quantity of supplements as well as the basal diet used, the agro‐ecology in which the experiment was conducted and the age of the animals.

It is obvious that animals with better BW and body condition fetch a higher market price than those with lower BW and poor body condition; thus, the higher economic gain of Washera sheep and sheep fed a higher supplement amount is due to the animals’ higher BW and better body condition. Many studies have reported similar observations to the current study (Adugna et al. 2023; Ayele et al. 2022; Yimenu and Abebe 2023).

5. Conclusion

In conclusion, the results of this study showed that effective microorganism‐treated wheat straw feeding at 15% t TDMI versus 10% TDMI improved DM intake, rate of digestion and FBWCE, supported 33 g/day more AEBWG and resulted in 279 more NRs over A1‐fed sheep. The findings also revealed that Washera sheep consumed more DM, increased more BW and had a larger NR than Horro sheep. As a result of the current findings, smallholder farmers may consider using Washera sheep for greater economic return on low‐quality feed. However, further research is needed to clearly distinguish the potential of these two breeds in cases of poor‐quality feed utilization.

Author Contributions

Desalegn Tesfaw contributed to the writing of the research proposal, the collection of data, the analysis of data, the interpretation of the data and the preparation of the draft document. Shashie Ayele and Melese Gashu participated as Desalegn Tesfaw, except for data collection. Shashie Ayele prepared the manuscript for the journal, and all authors read and approved the final manuscript.

Ethics Statement

Our universities have no established ethical approval committee; however, all animal management activities are done following the international guiding principles listed by Council for International Organizations of Medical Sciences and International Council for Laboratory Animal Science (2012).

Conflicts of Interest

The authors declare no conflicts of interest.

Peer Review

The peer review history for this article is available at https://publons.com/publon/10.1002/vms3.70330.

Data Availability Statement

The data used to prepare this article came from our experiment, and it is possible to access the data on personal request from the first and/or corresponding authors.