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Article

Forage Availability and Quality, and Feeding Behaviour of Indigenous Goats Grazing in a Mediterranean Silvopastoral System

1
Regional Center of Agricultural Research of Tangier, National Institute of Agricultural Research, Avenue Ennasr, BP 415 Rabat Principale, Rabat 10090, Morocco
2
Department of Veterinary Management of Animal Resources, FARAH, Faculty of Veterinary Medicine, University of Liège, 4000 Liege, Belgium
3
Department of Animal Production and Pastoralism, Ecole Nationale d’Agriculture de Meknès, Meknes 50001, Morocco
4
Precision Livestock and Nutrition Unit, TERRA Teaching and Research Center, Gembloux Agro-Bio Tech, University of Liège, 5030 Gembloux, Belgium
*
Author to whom correspondence should be addressed.
Ruminants 2022, 2(1), 74-89; https://doi.org/10.3390/ruminants2010004
Submission received: 29 November 2021 / Revised: 9 January 2022 / Accepted: 12 January 2022 / Published: 13 January 2022
(This article belongs to the Special Issue Feature Papers of Ruminants 2021-2022)

Abstract

:
The aim of this study was to evaluate the feeding behaviour of indigenous goats and the selection drivers of different plant species in a Mediterranean forest rangeland. To achieve this goal, the seasonal variations in terms of forage availability and quality of ingested plant species were studied during three grazing seasons. In the same period, eight indigenous goats of Beni Arouss breed were selected to explore the seasonal changes in their browsing behaviour. Forage quality was determined by the hand-plucking technique. The results showed a wide seasonal variation in forage availability and quality, and feeding behaviour. Woody species were more selected independently of the season (p < 0.001). The crude protein content varied from 53.3 g/kg of dry mater (DM) for Erica arborea in summer to 197 g/kg DM for Calicotome villosa in autumn (p < 0.001). Despite the high condensed tannins content in selected shrubs, they were highly consumed. In vitro organic matter digestibility (IVOMD) and metabolizable energy (ME) had recorded the highest contents in herbaceous during spring. Shrubs and trees contain the lowest levels of IVOMD (<500 g/kg) and ME (<7.2 MJ/kg) during autumn and summer. It is concluded that seasonal changes in forage availability and quality did not necessarily affect the indigenous goats’ preference. These findings could help goat herders to develop feeding and grazing systems while increasing the performance of goats in the Mediterranean silvopastoral system.

1. Introduction

Silvopastoral systems are an important component of extensive goat production in the Mediterranean region. In Morocco, these forest rangelands guarantee year-round feed resources for grazing goats. They provide 80% of diet requirements of grazing animals in mountainous areas (High Atlas and Northern Morocco). Four million heads of goats (i.e., approximately 70% of the national herd) graze on forest pasturelands [1]. The silvopastoral system contributes between 68% and 100% of the incomes of farmers, playing an essential socio-economic role [2].
In Northern Morocco, there is one indigenous goat breed named Beni Arouss, which was only recently officially recognized by the Moroccan Ministry of Agriculture and Rural Development (Official Journal of Morocco; N° 6, 430; 01/2016). The mountainous forest rangeland constitutes the exclusive feed resources of this indigenous goat breeds. The intense meat flavor of this indigenous goat is greatly appreciated by consumers. Their lactation lasts 120 days, averaging 0.504 kg/goat. In addition, this breed shows excellent tolerance to diseases [3]. Published works about this indigenous goat have only explored the aspects related to its genetic characteristics [4] and the effect of alternative feed resources’ incorporation on goat meat and milk production [5,6]. Domestic goats (Capra hircus) have shown better performance and adaptability in harsh environments than other domesticated ruminants [7], where they face complex feed sources dominated by heterogeneous woody species.
One of the main problems of the extensive livestock systems in Morocco is the lack of information on pasture quality and feeding behaviour of indigenous goats under grazing conditions. Despite various studies focused on the European Mediterranean countries [8,9,10,11,12,13,14], there is little information in the literature on the browsing behaviour of indigenous goats in the mountainous silvopastoral units. Understanding the seasonal variation of forage availability and quality, and feeding behaviour of indigenous goats is crucial to develop targeted decisions to improve feeding and grazing strategies for enhanced sustainability and performances of animal production system. In order to address this issue, this work was undertaken in a mountainous silvopastoral system of the Southern Mediterranean region (Northern Morocco) to study the seasonal variations in terms of forage availability and quality of ingested plant species and browsing behavior of indigenous grazing goats.

2. Materials and Methods

2.1. Experimental Forest Pasture

An experiment was carried out in a mountainous forest pastureland located at an altitude ranging between 250 and 550 m above sea level in the Beni Arouss region in Northern Morocco (35°18′ N, 5°34′ W) (Figure 1). The climate is Mediterranean, with an annual rainfall varying between 400 and 700 mm. Temperatures range from 3 to 14 °C in winter and from 18 to 38 °C in summer (minimum and maximum, respectively) [15]. The pastureland is a Mediterranean forest with vegetation units from low formations of Cistus spp. (inclusive of C. crispus L., C. monspeliensis L., and C. salviifolius L.) to oak groves. Vegetation includes Quercus spp. (inclusive of Q. coccifera L., Q. ilex L., and Q. suber L.) associated with shrublands dominated by Arbutus unedo L. and Cistus spp. [16].

2.2. Experimental Animals and Feeding Behaviour

Eight indigenous Beni Arouss meat goats (30 ± 2.6 kg liveweight and 36 ± 6 months of age) were chosen from a local goat flock composed of 79 animals browsing in the study area. The pasture is grazed by goats during all seasons, except winter when they are confined. During winter, forest rangelands’ access is very limited in the studied area, and during this time herders’ trim oak tree branches (Quercus spp.) as forage for goats. The average grazing time was estimated between 7 h and 12 h depending on grazing day and season. Goats’ feeding behavior was evaluated within the three seasons by the direct observation method [17]. This method seems to be better suited to recording data on diversified vegetation and at different time scales. The improved direct observation method developed by Agreil and Meuret [18] allowed for the continuous observation of the feeding behaviour of sheep and goats. The originality of this method results from its capacity to couple detailed and short-term measurements at bite scale with long-term intake balance. However, in a diversified grazing environment such as north Moroccan forest rangeland, where the number of eaten species is over twenty consumed per day, too many bite categories have to be defined, making it difficult to identify and record them in real-time. The direct observational methodology was chosen thanks to our skill of this technique. The observation procedure was realized during three consecutive grazing days over three seasons for one year: spring (green season), summer (dry season), and autumn. Data were collected by observing each experimental indigenous goat for 10 min, with an interval of 5 min, over the whole grazing days (morning, mid-day, and afternoon) [19]. Before starting the observation procedure, observers spent three days with goats to accustom them to the presence of an unfamiliar person, as detailed by Meuret and Provenza [20]. According to González-Pech et al. [21], the familiarization procedure was considered as successful when the observer could remain closer than 1 m from to the observed animal without disturbing their grazing activities. Trained observers recorded the selected plant species and the number of bites per consumed plant part, which allowed generating the total number of bites (TB). The percentage of bites per plant species (TBi, %) was calculated using the following equation: TBi = NBi/TB; where NBi is the number of observed bites of plant i. To determine the average mass per bite, the observer mimicked the bite mass (BM, g DM) for each plant species selected by goats (only the consumed parts of the plant) using the hand-plucking procedure (100 simulated plucks per plant per season) [22]. The hand-plucked samples were collected in special bags and taken to the laboratory in order to determine the average BM of each consumed species. This procedure allowed estimation of the intake rate (IR, g DM/min) and diet composition (DC, %). The DC was reported as the percentage of each consumed species in the diet according to the following equation: DC i = ( NB i   × BM i )   /   ( i = 1 n ( NB   ×   BM ) ) ; where DCi is the proportion of the plant i in the diet, BMi is the mean bite mass of the plant i, and n is the number of plant species. The IR was calculated as IR = BR × BM; where BR is the bite rate (BR, n/min).

2.3. Forage Availability and Diet Selection

Before starting the experiment, seasonal forage availability was estimated in order to calculate the seasonal diet selectivity [23,24]. Forage availability of each selected plants species was estimated on the basis of those effectively consumed by goats using the quadrat method [19,25]. Several numbers and sizes of quadrats were tested to obtain the most representative quadrat to minimize the effect of rangeland heterogeneity. Therefore, forty quadrats of 40 m2 (4 m × 10 m) for woody species and forty quadrats of 1 m² for herbaceous species (each one embedded within one woody quadrat) were implemented seasonally in rangeland along the usual grazing paths [9]. The non-destructive method known as the reference module was used for shrubs and trees. For trees, we considered only the accessible and consumed plant parts for goats. For herbaceous, a destructive method was used, where all herbaceous biomass was cut. Biomass samples were oven-dried at 40 °C to constant weight to obtain the dry matter (DM).
Several indexes are employed to estimate diet selectivity [26]. The selectivity measures the selection of plant species in relation to their abundance or availability in the forest rangeland. Plant species that constitute a larger proportion of the diet than their availability are considered preferred; conversely those proportionately underrepresented in the diet are avoided. The most common measure is Ivlev selectivity index (SI) as follows [27]: SI = (% forage in the diet − % forage availability)/(% forage in the diet + % forage availability). According with its outcomes, diet selectivity could be classified into categories: very high (>0.5), high (0–0.5), low (−0.5–0), and very low (<−0.5) selectivity, based on goats’ preferences [28].

2.4. Forage Quality

To determine the nutritional quality of forage in each studied season, analyses were achieved on three different hand-plucked samples of each pastoral species selected by the experimental grazing goats. The collected samples were directly conducted to the laboratory to determine the chemical composition and the digestibility parameters. All analyses were made in triplicate. The nutritional quality of plant groups is the average of the composition of pastoral species selected according to their category (herbaceous, shrubs, or trees).

2.4.1. Chemical Composition

The collected samples were weighed before being dried until they reached a constant weight at low temperature (40 °C) to avoid changes in tannins content and activity [29]. The dried samples were milled with a sieve mesh size of 1 mm to evaluate the chemical composition. Organic matter (OM), crude protein (CP), and ether extract (EE) analyses were performed according to the Association of Official Analytical Chemists [30]. The OM was determined after calcination in a muffle furnace for 12 h. Nitrogen (N) content was measured by the Kjeldahl method and the crude protein (CP) was calculated by multiplying N by 6.25. The EE were extracted by the Soxhlet method.
All fibers in the studied samples were estimated using ANKOM 200 Fiber Analyzer (ANKOM Technology, New York, NY, USA) inclusive of residual ash. The neutral detergent fiber (NDF) method was described by Mertens’ [31]. The method 973.18 of AOAC [32] was used to estimate acid detergent fiber (ADF). Lignin (ADL) content was evaluated according to Robertson and Van Soest’s [33] method by cellulose solubilization from ADF, using sulphuric acid. Condensed tannins (CT) were estimated by butanol-HCl and ferric reagents according to Porter et al. [34].

2.4.2. Digestibility and Metabolizable Energy

The methods for in vitro dry matter (IVDMD) and organic matter (IVOMD) digestibility are well described by Mabjeesh et al. [35]. They were determined using DAISYII Incubator (ANKOM Technology, New York, NY, USA), which tries to simulate ruminal digestion [36]. Briefly, 0.5 g of each sample was placed in ANKOM filter bags (F57) and was incubated at 39.5 °C in jars (24 bags/jar), which contained an inoculum. This inoculum was a mixture of 4/5 volume of artificial saliva and 1/5 of rumen liquor. After 48 h of incubation, IVDMD and IVOMD were calculated by weighing the residuals DM and OM comparing to initial incubated quantities. The used rumen liquor in the inoculum was collected from five goats at a local slaughterhouse as widely described by El Otmani et [37]. These goats grazed in a forest pastureland similar to the studied area.
The metabolizable energy (ME; MJ/kg DM) of the studied plants were predicted based on the digestibility results, according to the following formula suggested by AOAC [32]: ME = 0 . 17   ×   DMD   -   2 , where DMD is the dry matter digestibility in %.

2.5. Statistical Analysis

Data analyses were performed using SAS software v9.4 (SAS Inst. Cary, NC, USA). Before analyses, data expressed as percentage were arcsine-square root-transformed to normalize their distribution [38]. Bite mass was analyzed using two-way analysis of variance (ANOVA) with either plant species (n = 15) or plant groups (i.e., herbaceous, shrubs and trees), seasons (i.e., spring, summer, and autumn), and their interaction. Forage availability and quality (chemical composition, digestibility, and metabolizable energy) were analyzed using a general linear model (GLM) procedure of SAS in a factorial structure. They were compared between plant species or plant groups and seasons and their interaction. Feeding behaviour data (selectivity, bite rate, intake rate, and diet composition) were analyzed according to the PROC MIXED procedure of SAS [39] with the daily observation on each goat as experimental unit. Differences in feeding behaviour were assessed considering the effects of plant species or plant groups, seasons and their interaction. The individual goat was considered as a random effect to prevent this variance from being incorporated in the error term of the analysis. Pearson correlation analysis was used to establish the relationships between chemical component variables, digestibility, intake, and selection. For all variables analyzed, the significance level was declared at p < 0.05. In case of significant effect, means were compared using the Tukey’s test.

3. Results

3.1. Forage Availability and Diet Selection

The season affected the average forage availability of the studied pasture (p < 0.001). The spring recorded the higher forage production significantly in comparison with the summer and autumn (Figure 2A).
Three distinct groups of plant species dominated the forest vegetation and composed the goats’ diet, namely: herbaceous plants (mainly Anthemis cotula L., Brachypodium distachyon L., Bromus rigidus Roth, Calamintha nepeta (L.) Kuntze, Cynodon dactylon (L.) Pers., Eryngium tricuspidatum L., Lythrum junceum Banks and Sol., Rumex bucephalophorus L.), shrubs (Arbutus unedo L., Calicotome villosa (Poir.) Link, Cistus spp., Erica arborea L., Lavandula stoechas L., Myrtus communis L., Phillyrea media L., Pistacia lentiscus L., and Rubus ulmifolius Schott.), and trees (Quercus spp. and Olea europaea subsp. O. europaea L. var. sylvestris (Mill) Lehr).
The seasonal variation of forage availability and selectivity towards shrubs, trees, and plant groups of indigenous grazing goats are detailed in Table 1, Table 2 and Table 3, respectively.
Forage availability varied with the season (p < 0.01), species, or plant groups (p < 0.01) and their interaction (p < 0.001), except for the effects of the interaction of season and species on tree species availability (p = 0.956) and the season effect on plant group availability (p = 0.335). Shrubs were the most available forage, with C. salviifolius (42.7%) in summer, E. arborea (41.8%) in autumn, and A. unedo (31.4%) in spring.
Diet selection was affected by season, species or plant groups and their interaction (p < 0.001). The shrubs M. communis and P. media were highly selected across all seasons. C. villosa, P. lentiscus, and R. ulmifolius were mostly selected in summer and autumn. The same tendency was observed for the selectivity of each tree species (Quercus spp. and O. europaea). Cistus spp. and L. stoechas had high selectivity only in spring. E. arborea was highly selected only during the summer. All plant groups had low selectivity in all three seasons, apart from herbaceous in spring and the tree group in summer and autumn.

3.2. Feeding Behaviour

The season affected the average of bite and intake rates (p < 0.05; Figure 2B,C). On the one hand, the higher biting rate was recorded equally during summer and autumn (about 22 bites/min). On the other hand, the higher intake rate was recorded during spring (5.57 g DM/min).
Data on the seasonal variation of feeding behaviour (bite mass, total bites, and diet composition) towards shrubs, trees, and plant groups of indigenous grazing goats are detailed in Table 1, Table 2 and Table 3, respectively. All measured parameters were affected by season (p < 0.01), species, or plant groups (p < 0.001), and their interaction (p < 0.001). Overall, during summer and autumn, the highest values of feeding behaviour parameters driving intake rates (BM, TB, and DC) were recorded on A. unedo, M. communis, and P. lentiscus for shrubs and on O. europaea and Q. suber for trees. During spring, the highest values were observed on Cistus spp. and L. stoechas.
The trees group registered the largest values of BM in autumn (0.204 g DM/bite) and summer (0.188 g DM/bite), and the smallest values in spring (0.058 g DM/bite). During spring, the highest BM was observed in herbaceous (0.361 g DM/bite). For the shrubs group, the BM varied from 0.155 to 0.188 g DM/bite, and the total percentage of bites varied from 67.9 to 88.9%. The DC of shrubs ranged from 63.6 to 88.9% across all studied seasons.

3.3. Forage Quality

The outcomes for the seasonal variation in the chemical composition, IVOMD, and ME of selected plant groups by indigenous grazing goats are presented in Table 4. The detailed nutritive quality of plant groups in the three seasons shows that half of the parameters were affected by season (DM, OM, CP, IVOMD, and ME; p < 0.05), except for EE, fibers, and CT (p > 0.05). Additionally, as expected, the forage quality differed according to the plant group even if for the EE concentrations only tended to differ (p = 0.093). The significant interaction effects of season and plant groups were obtained only for OM (p = 0.036) and CP (p = 0.023) contents. The DM level was higher for all plant groups in the summer. The OM content was lower in herbaceous during the three seasons compared to shrubs and trees. The lowest and the highest CP contents were recorded in herbaceous during autumn (66.4 g/kg DM) and spring (169 g/kg DM), respectively. The EE levels of all plant groups were below 48 g/kg DM. Shrubs recorded the lowest concentrations of NDF (402 g/kg DM) and ADF (274 g/kg DM) during spring while they had the highest levels of ADL (187 g/kg DM) during the summer. Herbaceous had the highest ADF content (382 g/kg DM) in summer and the lowest ADL (61.3 g/kg DM) in spring. The CT levels showed a wide variation, ranging from 2.67 g/kg DM in herbaceous plants in spring to 86.6 g/kg DM in shrubs in summer. Both IVOMD and ME had recorded the highest contents in herbaceous during spring (823 g/kg and 12.2 MJ/kg, respectively). Shrubs and trees registered the lowest levels of IVOMD (less than 500 g/kg) and ME (less than 7.2 MJ/kg) during autumn and summer. Generally, herbaceous group had the highest IVOMD and ME independently of the season compared to other plant groups.
Information for the seasonal variation in the chemical composition, IVOMD, and ME of selected shrub species by indigenous grazing goats is presented in Table 5. Regarding shrubs, the quality of the forage was influenced by species, but also season and their interaction (p < 0.001), except for OM content which was not affected by season (p = 0.071). The DM ranged between 227 and 691 g/kg DM and the highest values were observed in the summer while the OM content recorded more than 848 g/kg DM. The CP level varied from 53.3 g/kg DM for E. arborea in summer to 197 g/kg DM for C. villosa in autumn, which also had the higher CP content (>187 g/kg DM) among all consumed shrub species in spring and summer. The lowest and highest contents of EE were observed during spring in C. crispus (15.9 g/kg DM) and in E. arborea (96.1 g/kg DM), respectively. Concerning fibers, the highest NDF and ADF contents were recorded in C. villosa during the three seasons and the highest ADL content in E. arborea during the summer. Although, the lowest concentrations of ADF and ADL were noted in R. ulmifolius during autumn, while the lowest NDF content was in C. crispus during the three seasons. The CT content ranged between 1.93 g/kg DM in L. stoechas (autumn) and 206 g/kg DM in P. lentiscus (summer). The C. villosa in autumn was the less digestible species with IVOMD of 359 g/kg and L. stoechas in spring was the more digestible with 717 g/kg. Overall, the highest values of IVOMD were observed in spring. E. arborea had the lowest ME with 4.41 MJ/kg DM in the summer. However, the highest energy level was observed in L. stoechas in spring with 10.4 MJ/kg DM.
Data on the seasonal variation in the chemical composition, IVOMD (g/kg), and ME of selected tree species by indigenous grazing goats could be seen in Table 6. All measured parameters depended significantly to the season (p < 0.05), species (p < 0.001) and their interaction (p < 0.001), except for CP and ADL contents which were similar between species (p = 0.144) and seasons (p = 0.507), respectively. The O. europaea had the highest moisture content compared to the other trees in all studied seasons. However, the highest DM was in Q. coccifera during summer. The OM levels varied from 914 to 970 g/kg DM. The CP concentration ranged from 66.6 g/kg DM in Q. coccifera (summer) to 109 g/kg DM in Q. ilex (spring). The lowest level of EE content was 18.3 g/kg DM in Q. coccifera (spring) and the highest level was 121 g/kg DM in O. europaea (summer). The NDF, ADF and ADL registered the highest contents in Q. suber (589 g/kg DM; spring), Q. coccifera (401 g/kg DM; autumn), and Q. ilex (191 g/kg DM; spring), respectively. In the three seasons, O. europea had the lowest NDF and ADF contents. The ADL content was the lowest in Q. coccifera during spring. The CT content was lower and higher during summer in O. europaea and Q. suber, respectively. Both IVOMD and ME recorded the highest concentrations in Q. coccifera during spring. Generally, the summer recorded the lowest contents of IVOMD and ME, except for O. europaea that had the smallest values in spring.
The outcomes for the correlation between chemical components and digestibility with intake and selection are presented in Table 7. The correlation of plants’ chemical components with intake rate showed no significant association of EE during all seasons and for fibers during summer and autumn. In spring, fibers and CT were negatively correlated with intake and selection (p < 0.01). During all seasons, CP was positively correlated with intake and selection (p < 0.05).

4. Discussion

4.1. Forage Availability and Diet Selection

The study revealed that shrubs, mainly A. unedo, Cistus spp., and E. arborea, formed the most available and prevalent forage species in the study area, which is in accordance with several authors [19,25], who studied the botanical composition of forest rangeland in Northern Morocco. The forage availability depended considerably on the season and the existing plant species. The low forage availability recorded in the summer and autumn could be due to the vegetation cycle and to the weather conditions more favorable to the growth of plants during spring. In the Mediterranean forests of Northern Morocco, Chebli et al. [19] also confirmed the strong seasonality of forage availability even for woody species that are usually less impacted by seasonal fluctuations.
According to Papachristou et al. [40], the bulk of the small ruminants’ diet includes a limited number of woody and herbaceous species, usually less than ten species. Some species despite their abundance in the pasture were negatively selected, and conversely. Similar results were announced by Baraza et al. [41] in the Mediterranean mountain forest of Spain and by Ventura-Cordero et al. [13] in a tropical deciduous forest of México. As reported by some studies [9,17], woody species were more selected by goats independently to the season. Despite the low availability of tree species (Quercus spp. and O. europaea) and some shrubs (M. communis, P. lentiscus, P. media, and R. ulmifolius) they were selected preferentially in summer and autumn. It could be supposed that goats select a wide range of mixed plant species in order to meet their foraging requirements. Likewise, Ventura-Cordero et al. [13] reported that diet selection was not necessarily correlated with the forage availability, but it appears more linked to satisfying the feed needs of goats. During spring, the great selectivity for herbaceous could be associated with their higher availability and quality. In Eastern and Northern Mediterranean rangelands, Papachristou [42] and Glasser et al. [11] also stated the higher selection of herbaceous during spring due to their high nutritive value and availability compared to the other seasons. According to Ferreira et al. [43], goats increase their preference for herbaceous species in spring due to their easy access, better flavor, and high digestibility. As described by Dziba et al. [44], the high elasticity of goats’ diet could be explained by their great ability to switch from one vegetation strata to another. Generally, goats have been considered as opportunistic grazers in forest pasture and marginal land [45,46].

4.2. Feeding Behaviour

The seasonality of feeding behaviour was confirmed by several studies conducted in the Monte desert of Argentina [47], South African woodland [48], and Greek woodland [14]. The results showed that woody species represented more than 90% of DC and TB in all seasons. The same trend of the feeding behaviour of goats was reported by Manousidis et al. [17]. Cistus spp. and L. stoechas were more grazed during spring compared to summer and autumn due to the presence of fresh leaves and new long-shoots. Aharon et al. [9] reported that goats spent more time browsing Cistus spp. during spring compared to other seasons despite the abundance of herbaceous species. On the opposite, Papachristou [42] reported that goats in Greek forest rangeland ingested mainly Cistus spp. during autumn. The high ingestion of trees, mainly Quercus spp., was observed during summer and autumn. This increase could be explained by intake reduction of some plants such as Cistus spp. species and herbaceous species. Similar findings were reported by Manousidis et al. [17] concerning the high contribution of Quercus spp. to the diet of goats’ in a similar Mediterranean woodland area. As expected, when herbaceous species were less abundant and dry, goats trended to more graze woody species [49]. In agreement with Barros et al. [23], goats recorded faster BR in the summer and autumn in order to maximize their IR. Papachristou [42] also signaled an increase of BR from spring to summer which is in accordance with our outcomes. Despite the high availability of A. unedo and E. arborea, they were avoided during all seasons. C. villosa, Quercus spp., M. communis, and P. lentiscus were highly consumed by goats mainly in the fall and summer regardless of their low availability. Cistus spp. and L. stoechas were selected proportionally to their abundance only during the spring.

4.3. Forage Quality: Chemical Composition, Digestibility and Metabolizable Energy

Chemical analyses of the hand-plucked samples appear to reflect the nutritive value of the diet consumed by grazing goats [16].
The analyses showed a wide variability of pasture quality, which is in accordance with previous grazing studies conducted in tropical deciduous forest [21], South African rangeland [48] and Mediterranean woodland [16]. The seasonal changes of feed quality could be explained by the chemical and physiological plant variations during the different growth stages [50]. The CP was higher during spring for all species because plants contain the maximum CP content during the vegetative stage [51]. The decrease of this parameter in the summer agrees with the literature [52,53] because it drops with physiological maturity stage of the plant [54]. The range of 60–70 g/kg DM of CP is the limit threshold for an efficient feed utilization; a lower CP content negatively affects feed intake and digestibility [55]. In the present work, all species but A. unedo and E. arborea during summer had higher CP values than this threshold. As reported by Dziba et al. [44], it could be assumed that due to its palatability and high content on CP, C. villosa was highly consumed in summer and autumn despite the presence of spines known for their negative effect on BR and IR. According to Min et al. [56], the CT concentration of 20–45 g/kg DM has a negative effect on protein digestibility and proteolytic bacteria, and more than 55 g/kg DM reduces the voluntary feed intake of grazing ruminants [57,58]. Thus, except for herbaceous, C. villosa, L. stoechas, P. media, and O. europaea, all pastoral species had CT content higher than this maximum level. However, even with a high content of CT, the shrubs group were highly consumed in spring and autumn. These finding are consistent with Fomum et al. [48] and Mkhize et al. [59], who reported no correlation between CT and feed intake of goats. The lack of CT effect on forage intake and selectivity could be explained by the ability of goat to balance their diet and dilute secondary compounds by consuming a mixture of plant species [60,61]. Further, animals exposed to a tannin-rich environment have the capacity to produce proline-rich proteins capable of irreversibly binding the CT [57,59]. Nevertheless, goats have a specificity compared to other ruminants that their ruminal microbiota is able to valorize feed with low nutritional values due to their cellulolytic bacteria and the tanninase activity [62]. The high values of digestibility in spring are attributed to its positive dependence on proteins and negative correlation with ADF and ADL [16]. In the summer, OM digestibility declines because of fibers increase [63] and cell wall lignification [64] which are considered as limiting factors for plant digestibility [65]. Most of the pastoral species had a low digestibility and consequently a low energy content (IVOMD< 550 g/kg; ME < 8 MJ/kg DM) except for herbaceous and some shrubs (A. unedo and Cistus spp.), which their values varied from medium (550–700 g/kg IVOMD; ME: 8–10 MJ/kg DM) to higher nutritional values (IVOMD > 700 g/kg; ME > 10) especially in spring [66]. As reported by Paton [63], ME depends mainly on IVOMD. The positive correlation between CP with intake and selection is consistent with Mkhize et al. funding [59]. Conversely, Fomum et al. [48] observed no correlation between intake and CP in both the dry and rainy seasons. During spring, condensed tannins affect negatively intake [67]. There was no significant correlation between condensed tannins and intake during dry and rainy seasons [48]. Overall, goats select species with high CP and digestibility, and low fibers contents basis in accord with the literature [40]. Goats selected successively shrubs, herbaceous, and trees in spring and shrubs, trees, and herbaceous in autumn. Their preference was based on the high content of CP and the availability of the selected plant groups. Emmans [68] reported that animal selects among available plant species, those with nutritional values nearest to its dietetic requirements. Barroso et al. [28] added that the diet of goats is rather related to many variables hardly measurable than just nutritional value. According to the literature, diet of goats depended mainly on their nutritional requirements, physical traits such as shoot morphology and leaf phenology [59], environmental circumstances [24], and on the specific flavor of each consumed species [69].

5. Conclusions

The results emphasized the importance of the Southern Mediterranean silvopastoral areas for indigenous goats. The dietary quality of ingested forage and feeding behaviour of goats are currently known. Most studied parameters vary across seasons. Woody species are the most selected species by the indigenous goats. Their intake did not necessarily depend on the forage availability and nutritional value of plant species; it could be rather related to ensuring they meet their feeding needs as best as possible. Overall, these findings could be used as the first guide for future studies and managers interested in feeding behaviour of grazing goats in the Mediterranean forest rangeland of northern Morocco. The goats’ ability to select tanniferous woody forage and a wide range of plant species could probably promote the floristic biodiversity of forest rangeland, only under rational use condition of forage resources.

Author Contributions

Conceptualization, Y.C.; methodology, Y.C., M.C., J.-L.H., J.B., J.-F.C.; formal analysis, Y.C., S.E.O.; investigation, Y.C., S.E.O., A.K.; data curation, Y.C., M.C., J.-L.H., J.-F.C.; writing—original draft preparation, Y.C., S.E.O., M.C., J.-L.H., A.K., J.B., J.-F.C.; project administration, Y.C., J.-F.C.; funding acquisition, Y.C. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the Academy for Research and Higher Education-Development Cooperation Committee (ARES-CCD), Brussels, Belgium. This study is realized in the framework of the Research Project for Development (PRD: 2013–2018).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data presented in this study are available from the corresponding author on request.

Acknowledgments

The authors wish to acknowledge PRD Project and INRA staffs. We thank the herders for their patience and participation in this study.

Conflicts of Interest

The authors declare no conflict of interest.

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Figure 1. Location of the studied forest pasture (Northern Morocco).
Figure 1. Location of the studied forest pasture (Northern Morocco).
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Figure 2. Seasonal variation of forage availability (A), bite rate (B), and intake rate (C) of indigenous goats grazing in a Mediterranean forest rangeland. Means with different letters (a–c) indicate significant differences (p < 0.05).
Figure 2. Seasonal variation of forage availability (A), bite rate (B), and intake rate (C) of indigenous goats grazing in a Mediterranean forest rangeland. Means with different letters (a–c) indicate significant differences (p < 0.05).
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Table 1. Seasonal variation of forage availability, feeding behaviour, and selectivity towards shrubs of indigenous goats grazing in a Mediterranean forest rangeland of Northern Morocco.
Table 1. Seasonal variation of forage availability, feeding behaviour, and selectivity towards shrubs of indigenous goats grazing in a Mediterranean forest rangeland of Northern Morocco.
Availability
(%)
Selectivity IndexBite Mass
(g DM/Bite)
Total Bites
(%)
Diet Composition
(%)
Spring
Arbutus unedo31.4 c−0.983 n0.119 j0.619 mno0.234 lmno
Cistus crispus12.9 de0.549 c0.340 a26.1 a25.9 a
Cistus monspeliensis13.9 de0.255 d0.323 b23.6 b23.9 b
Cistus salviifolius18.3 d0.045 e0.349 a21.8 cd24.3 b
Calicotome villosa1.55 ij−0.919 lmn0.110 jk0.185 no0.064 no
Erica arborea16.6 e−0.784 jkl0.222 ef4.43 l2.74 i
Lavandula stoechas3.45 ghi0.757 b0.319 b22.2 cd22.5 b
Myrtus communis0.033 kl0.650 b0.080 mn0.319 no0.078 no
Pistacia lentiscus1.72 ijk−0.822 klmn0.091 lm0.505 no0.146 mno
Phillyrea media0.034 kl0.672 b0.070 n0.255 no0.057 no
Rubus ulmifolius0.010 l−0.984 n0.050 o0.006 o0.001 o
SEM0.0570.0250.0040.4020.043
Summer
Arbutus unedo12.02 gh−0.470 h0.220 ef12.8 i14.6 e
Cistus crispus10.5 ef−0.904 lmn0.110 jk1.29 mno0.75 kl
Cistus monspeliensis26.8 c−0.957 mn0.101 kl1.01 mno0.529 klm
Cistus salviifolius42.7 a−0.961 mn0.110 jk1.32 mn0.760 k
Calicotome villosa2.11 hi0.618 bc0.170 gh9.33 j8.25 g
Erica arborea1.71 ijk−0.139 de0.179 g16.7 gh15.7 e
Lavandula stoechas3.27 ghi−0.810 jklm0.100 kl1.28 mno0.673 kl
Myrtus communis0.338 jkl0.974 a0.260 c17.5 g23.6 c
Pistacia lentiscus0.197 jkl0.734 b0.242 d18.7 f23.4 c
Phillyrea media0.040 jkl0.969 a0.147 i12.7 i7.26 g
Rubus ulmifolius0.329 jkl0.740 b0.120 j7.32 k4.54 h
SEM0.0750.0290.0022.570.031
Autumn
Arbutus unedo30.7 bc−0.200 fg0.215 f17.3 e18.9 d
Cistus crispus2.77 ghi−0.890 lmn0.093 lm1.64 m0.788 kl
Cistus monspeliensis5.89 fg−0.962 lm0.090 lm1.01 mno0.470 klmn
Cistus salviifolius12.5 de−0.971 mn0.105 jkl1.09 mno0.552 klm
Calicotome villosa0.218 jkl0.600 bc0.165 gh0.902 mno0.725 klm
Erica arborea41.8 ab−0.265 g0.167 gh20.3 bc18.0 d
Lavandula stoechas2.91 ghi−0.518 hi0.090 lm3.66 l1.68 j
Myrtus communis0.150 jkl0.978 a0.242 d19.3 d23.5 c
Pistacia lentiscus3.00 ghi0.762 b0.233 de20.1 cd23.3 c
Phillyrea media0.078 jkl0.947 a0.163 h13.6 h11.2 f
Rubus ulmifolius0.037 kl0.093 e0.144 i1.13 nm0.831 kl
SEM0.0690.0280.0020.3280.035
p-Value
Season0.005<0.001<0.001<0.0010.002
Plant species <0.001<0.001<0.001<0.001<0.001
Season × Plant species<0.001<0.001<0.001<0.001<0.001
SEM, standard error of the mean. Within a column, values with different letters are significantly different (p < 0.05).
Table 2. Seasonal variation of forage availability, feeding behaviour, and selectivity towards trees of indigenous goats grazing in a Mediterranean forest rangeland of Northern Morocco.
Table 2. Seasonal variation of forage availability, feeding behaviour, and selectivity towards trees of indigenous goats grazing in a Mediterranean forest rangeland of Northern Morocco.
Availability
(%)
Selectivity
Index
Bite Mass
(g DM/bite)
Total Bites
(%)
Diet Composition
(%)
Spring
Olea europaea9.48 c−0.655 de0.071 g13.1 d23.6 b
Quercus coccifera20.9 b−0.929 f0.071 g2.09 f3.52 e
Quercus ilex28.6 b−0.793 ef0.060 h10.1 e16.0 cd
Quercus suber40.9 a−0.464 d0.029 i74.8 a56.9 a
SEM4.950.0270.0022.660.271
Summer
Olea europaea9.46 c0.979 a0.191 c26.6 c20.6 b
Quercus coccifera19.1 b0.868 ab0.139 f10.8 e18.2 c
Quercus ilex25.2 b0.619 c0.139 f16.9 d9.60 d
Quercus suber46.2 a0.906 ab0.282 a45.6 b51.6 a
SEM4.000.0130.0040.9281.01
Autumn
Olea europaea5.00 c0.714 bc0.205 b15.6 d14.9 cd
Quercus coccifera24.3 b0.572 c0.171 d18.6 cd15.5 cd
Quercus ilex24.5 b0.652 c0.153 e23.9 c18.2 c
Quercus suber46.2 a0.941 a0.289 a41.8 b51.3 a
SEM7.830.0290.0030.8450.109
p-Value
Season<0.001<0.001<0.001<0.001<0.001
Plant species0.008<0.001<0.001<0.001<0.001
Season × Plant species0.956<0.001<0.001<0.001<0.001
SEM, standard error of the mean. Within a column, values with different letters are significantly different (p < 0.05).
Table 3. Seasonal variation of forage availability, feeding behaviour, and selectivity towards plant groups of indigenous goats grazing in a Mediterranean forest rangeland of Northern Morocco.
Table 3. Seasonal variation of forage availability, feeding behaviour, and selectivity towards plant groups of indigenous goats grazing in a Mediterranean forest rangeland of Northern Morocco.
Availability
(%)
Selectivity IndexBite Mass
(g DM/bite)
Total Bites
(%)
Diet Composition
(%)
Spring
Herbaceous8.49 c0.079 b0.361 a8.10 d10.7 d
Shrubs90.10 b−0.383 d0.188 c88.9 a88.9 a
Trees1.41 de−0.710 e0.058 f2.99 e0.37 f
SEM3.740.0180.0072.702.78
Summer
Herbaceous8.91 c−0.466 d0.110 e3.12 e1.66 e
Shrubs89.02 b−0.019 c0.160 d67.9 b63.6 b
Trees2.07 d0.843 a0.188 c28.9 c34.7 c
SEM3.660.0380.0021.841.74
Autumn
Herbaceous2.56 d −0.037 c0.105 e5.56 de1.86 e
Shrubs96.84 a−0.165 d0.155 d69.1 b67.7 b
Trees0.600 e0.720 a0.204 b25.4 c30.4 c
SEM4.120.0290.0030.4671.87
p-Value
Season 0.335<0.001<0.001<0.001<0.001
Plant groups <0.001<0.001<0.001<0.001<0.001
Season × Plant groups<0.001<0.001<0.001<0.001<0.001
SEM, standard error of the mean. Within a column, values with different letters are significantly different (p < 0.05).
Table 4. Seasonal variation in the chemical composition (g/kg DM), IVOMD (g/kg), and ME (MJ/kg DM) of selected plant groups by indigenous Beni Arouss goats grazing a Mediterranean forest rangeland of Northern Morocco.
Table 4. Seasonal variation in the chemical composition (g/kg DM), IVOMD (g/kg), and ME (MJ/kg DM) of selected plant groups by indigenous Beni Arouss goats grazing a Mediterranean forest rangeland of Northern Morocco.
DMOMCPEENDFADFADLCTIVOMDME
Spring
Herbaceous472 bc915 b169 a20.5 a529 ab344 ab61.3 c2.67 b823 a12.2 a
Shrubs466 bc940 ab109 b45.3 a402 c274 b145 ab65.4 ab575 d8.10 d
Trees548 ab959 a95.2 bc39.5 a511 ab349 ab164 a42.6 ab547 de7.86 d
SEM15.64.194.414.2711.38.996.928.2614.00.23
Summer
Herbaceous628 a878 c86.6 bc23.1 a581 a382 a79.9 bc3.70 b652 c9.60 c
Shrubs557 ab947 ab89.7 bc47.8 a453 bc304 ab187 a86.6 a460 f6.29 e
Trees597 a947 ab77.1 bc47.9 a508 ab340 ab162 a55.7 ab459 f6.52 e
SEM13.75.244.544.6912.910.310.89.1410.40.18
Autumn
Herbaceous537 abc847 d66.4 c21.4 a455 bc281 b64.2 c3.30 b724 b10.8 b
Shrubs429 c942 ab90.3 bc37.2 a449 bc311 ab179 a78.6 a458 f6.33 e
Trees563 ab951 a78.1 bc36.2 a489 b338 ab164 a49.7 ab496 ef7.15 de
SEM15.34.624.793.1810.310.39.728.5111.40.20
p-Value
Season 0.0030.020<0.0010.6690.0890.2950.5820.809<0.001<0.001
Plant groups <0.001<0.0010.0390.093<0.0010.001<0.001<0.001<0.001<0.001
Season × Plant groups0.2300.0360.0230.9830.0650.1500.5770.9930.1190.162
ADF, acid detergent fiber; ADL, acid detergent lignin; CP, crude protein; CT, condensed tannins; DM, dry matter; EE, ether extract; IVOMD, in vitro organic matter digestibility; ME, metabolizable energy; NDF, neutral detergent fiber; OM, organic matter; SEM, standard error of the mean. Within a column, values with different letters are significantly different (p < 0.05).
Table 5. Seasonal variation in the chemical composition (g/kg DM), IVOMD (g/kg), and ME (MJ/kg DM) of selected shrub species by indigenous Beni Arouss goats grazing a Mediterranean forest rangeland of Northern Morocco.
Table 5. Seasonal variation in the chemical composition (g/kg DM), IVOMD (g/kg), and ME (MJ/kg DM) of selected shrub species by indigenous Beni Arouss goats grazing a Mediterranean forest rangeland of Northern Morocco.
DMOMCPEENDFADFADLCTIVOMDME
Spring
Arbutus unedo572 efg961 abcde77.8 jklmn71.8 b348 no248 klmnop112 hij92.5 hij638 b9.14 b
Cistus crispus415 pq954 abcde112 cde15.9 k303 p267 jklm107 hijk16.4 pq696 a9.92 a
Cistus monspeliensis583 def900 hi97.7 efgh55.9 c372 mn217 pqr205 de43.7 no593 cd8.38 cd
Cistus salviifolius489 m878 ij105 def23.2 ijk412 ijkl252 klmno150 fg24.3 op620 bc8.66 bc
Calicotome villosa227 t918 efghi188 a28.8 ghi529 bc429 bc104 hijk3.42 q553 de7.90 def
Erica arborea567 efgh979 ab82.3 hijkl96.1 a437 ghi337 fg244 c114 efg499 fghi6.74 ghij
Lavandula stoechas293 s947 abcdef105 def90.9 a413 ijkl256 klmno172 f2.73 q717 a10.4 a
Myrtus communis556 fghi956 abcde92.2 fghij44.3 de382 klmn229 pqr119 hij103 ghi506 fgh7.20 efgh
Pistacia lentiscus542 ghij956 abcde96.8 efghi28.6 ghi451 fgh293 hij124 ghi173 b533 ef7.42 efg
Phillyrea media522 jkl961 abcde110 de25.1 hijk398 jklm271 jkl177 ef3.23 q527 efg7.46 efg
Rubus ulmifolius363 r925 defgh135 b17.7 jk378 lmn214 qr79.9 klm144 c441 lmno5.81 klmn
SEM20.95.435.194.9410.110.68.5210.514.70.24
Summer
Arbutus unedo662 ab967 abcd54.8 op93.6 a464 efg328 fg246 c133 cde556 de7.75 def
Cistus crispus537 hij952 abcdef62.8 nop24.9 hijk247 q236 mnopq216 cd69.5 klm443 klmno5.88 klmn
Cistus monspeliensis691 a943 bcdefg82.8 ghijkl90.4 a493 cde266 jklm171 f64.4 lm408 op5.33 mn
Cistus salviifolius440 op849 j81.5 hijklm51.9 cd502 bcd352 ef245 c85.8 ijk443 klmno6.03 jklm
Calicotome villosa496 ml987 a190 a25.8 hijk616 a464 a112 hij2.47 q470 hijkl6.29 ijkl
Erica arborea656 b969 abc53.3 p91.7 a536 b403 cd373 a119 defg360 q4.41 p
Lavandula stoechas476 mn944 bcdefg87.4 ghijk36.2 efg468 defg313 gh226 cd3.51 q501 fghi6.84 ghi
Myrtus communis535 ijk946 abcdef73.4 klmn39.7 ef366 mno233 nopq95.4 ijkl129 cdef566 de7.93 cde
Pistacia lentiscus619 c948 abcdef99.5 defg23.8 hijk486 def263 jklmn178 ef206 a454 jklmn6.53 hijk
Phillyrea media612 cd966 abcd85.7 ghijk27.0 ghij434 ghij268 jklm127 gh2.57 q417 nop5.80 klmn
Rubus ulmifolius405 q944 bcdefg115 cd20.8 ijk372 mn218 pqr72.1 lm138 cd438 lmno6.38 ijk
SEM16.46.426.455.0316.613.214.711.210.50.17
Autumn
Arbutus unedo447 no952 abcdef64.6 mnop72.1 b495 cde380 de232 cd124 cdef395 pq5.22 no
Cistus crispus340 r927 cdefgh74.7 klmn17.4 jk375 mn255 klmno173 f58.1 mn510 fgh7.16 fgh
Cistus monspeliensis369 r936 cdefgh66.7 lmnop86.0 a436 ghi307 ghi228 cd79.3 jkl508 fgh6.92 ghi
Cistus salviifolius348 r903 ghi67.8 lmnop39.6 ef485 def293 hij230 cd51.5 mn464 ijklm6.34 ijk
Calicotome villosa295 s955 abcde197 a24.8 hijk594 a446 ab126 gh2.09 q359 q4.57 op
Erica arborea506 klm968 abc68.0 lmnop42.9 def584 a459 ab323 b117 efg426 mnop5.56 lmn
Lavandula stoechas405 q912 fghi70.5 klmno33.7 fgh436 ghi294 hij211 d1.93 q526 efg7.40 efg
Myrtus communis434 opq946 abcdefg80.5 ijklm22.5 ijk334 op243 lmnopq92.1 jkl111 fgh492 ghij7.33 efg
Pistacia lentiscus591 cde952 abcdef98.4 defgh22.5 ijk419 hijk279 ijk168 f195 a483 hijk6.75 ghij
Phillyrea media575 ef963 abcd78.3 jklmn28.5 ghi425 hij266 jklm123 ghi2.93 q427 mnop5.93 klmn
Rubus ulmifolius411 pq944 bcdefg127 bc19.7 ijk361 no199 r61.2 m122 defg451 jklmn6.47 hijk
SEM16.13.806.773.8014.314.012.810.59.010.16
p-Value
Season<0.0010.071<0.001<0.001<0.001<0.001<0.001<0.001<0.001<0.001
Plant species<0.001<0.001<0.001<0.001<0.001<0.001<0.001<0.001<0.001<0.001
Season × Plant species<0.001<0.001<0.001<0.001<0.001<0.001<0.001<0.001<0.001<0.001
ADF, acid detergent fiber; ADL, acid detergent lignin; CP, crude protein; CT, condensed tannins; DM, dry matter; EE, ether extract; IVOMD, in vitro organic matter digestibility; ME, metabolizable energy; NDF, neutral detergent fiber; OM, organic matter; SEM, standard error of the mean. Within a column, values with different letters are significantly different (p < 0.05).
Table 6. Seasonal variation in the chemical composition (g/kg DM), IVOMD (g/kg), and ME (MJ/kg DM) of selected tree species by indigenous Beni Arouss goats grazing a Mediterranean forest rangeland of Northern Morocco.
Table 6. Seasonal variation in the chemical composition (g/kg DM), IVOMD (g/kg), and ME (MJ/kg DM) of selected tree species by indigenous Beni Arouss goats grazing a Mediterranean forest rangeland of Northern Morocco.
DMOMCPEENDFADFADLCTIVOMDME
Spring
Olea europaea466 g958 a78.7 cde97.4 b419 g317 d161 cd4.20 f511 c7.04 ef
Quercus coccifera567 f957 a105 a18.3 e489 f343 cd132 f18.4 e613 a8.93 a
Quercus ilex576 f952 a109 a18.7 e548 bc349 c191 a29.3 c515 c7.33 de
Quercus suber584 ef970 a88.4 bc23.4 de589 a386 ab174 abc119 b549 b8.13 b
SEM14.54.423.9110.119.67.646.6413.512.60.227
Summer
Olea europaea436 h914 b91.6 b121 a444 g255 f150 de2.57 f525 bc8.08 b
Quercus coccifera693 a963 a66.6 e25.4 d552 b389 ab172 bc21.4 de429 ef5.74 h
Quercus ilex611 cd951 a71.2 de19.3 e532 bcd353 c182 ab61.2 c421 f5.83 h
Quercus suber648 b959 a79.0 cde27.0 d502 ef363 bc144 ef138 a460 de6.43 g
SEM29.45.972.932.9312.515.64.9815.612.60.285
Autumn
Olea europaea422 h916 b81.1 bcd77.2 c443 g286 e179 abc2.77 f521 bc7.81 bc
Quercus coccifera629 bc967 a71.0 de23.0 de522 cde401 a175 abc16.8 e463 d6.50 g
Quercus ilex600 de963 a70.8 de18.8 e503 def347 c170 bc54.6 c477 d6.73 fg
Quercus suber602 de957 a89.4 bc25.9 d488 f317 d134 ef125 b525 bc7.58 cd
SEM24.96.492.587.218.7813.05.6314.38.400.168
p-Value
Season<0.0010.023<0.001<0.001<0.0010.0160.507<0.001<0.001<0.001
Plant species<0.001<0.0010.144<0.001<0.001<0.001<0.001<0.001<0.001<0.001
Season × Plant species<0.0010.001<0.001<0.001<0.001<0.001<0.001<0.001<0.001<0.001
ADF, acid detergent fiber; ADL, acid detergent lignin; CP, crude protein; CT, condensed tannins; DM, dry matter; EE, ether extract; IVOMD, in vitro organic matter digestibility; ME, metabolizable energy; NDF, neutral detergent fiber; OM, organic matter; SEM, standard error of the mean. Within a column, values with different letters are significantly different (p < 0.05).
Table 7. Correlation coefficient between chemical component variables and digestibility with intake and selection.
Table 7. Correlation coefficient between chemical component variables and digestibility with intake and selection.
EENDFADFADLCPCTIVDMDIVOMD
Intake rateSpring0.029−0.42 ***−0.39 ***−0.10 **0.11 **−0.38 ***0.52 ***0.57 ***
Summer0.0360.040.02−0.020.21 **0.58 ***0.09 **0.07 *
Autumn−0.06−0.030.090.060.08 *0.63 ***0.08 **0.11
SelectionSpring0.09 **−0.25 ***−0.27 ***−0.15 **0.19 **−0.36 ***0.51 ***0.53 ***
Summer−0.22 ***0.11 ***−0.01−0.45 ***0.26 ***0.10 ***0.07 *−0.03
Autumn−0.24 ***−0.120 ***−0.11 ***−0.36 ***0.07 *0.13 ***0.17 ***0.09 **
EE, ether extract; NDF, neutral detergent fiber; ADF, acid detergent fiber; ADL, lignin; CP, crude protein; CT, condensed tannins; IVDMD, in vitro dry matter digestibility; IVOMD, in vitro organic matter digestibility. Significance level (*** < 0.001, ** < 0.01, and * < 0.05).
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Chebli, Y.; El Otmani, S.; Hornick, J.-L.; Keli, A.; Bindelle, J.; Cabaraux, J.-F.; Chentouf, M. Forage Availability and Quality, and Feeding Behaviour of Indigenous Goats Grazing in a Mediterranean Silvopastoral System. Ruminants 2022, 2, 74-89. https://doi.org/10.3390/ruminants2010004

AMA Style

Chebli Y, El Otmani S, Hornick J-L, Keli A, Bindelle J, Cabaraux J-F, Chentouf M. Forage Availability and Quality, and Feeding Behaviour of Indigenous Goats Grazing in a Mediterranean Silvopastoral System. Ruminants. 2022; 2(1):74-89. https://doi.org/10.3390/ruminants2010004

Chicago/Turabian Style

Chebli, Youssef, Samira El Otmani, Jean-Luc Hornick, Abdelhafid Keli, Jérôme Bindelle, Jean-François Cabaraux, and Mouad Chentouf. 2022. "Forage Availability and Quality, and Feeding Behaviour of Indigenous Goats Grazing in a Mediterranean Silvopastoral System" Ruminants 2, no. 1: 74-89. https://doi.org/10.3390/ruminants2010004

APA Style

Chebli, Y., El Otmani, S., Hornick, J. -L., Keli, A., Bindelle, J., Cabaraux, J. -F., & Chentouf, M. (2022). Forage Availability and Quality, and Feeding Behaviour of Indigenous Goats Grazing in a Mediterranean Silvopastoral System. Ruminants, 2(1), 74-89. https://doi.org/10.3390/ruminants2010004

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