Seasonal feeding behavior of goat kids browsing in Mediterranean forest rangeland of Bouhachem Natural Park, Northern Morocco

Youssef Chebli, Hamza Boulaich, Mouad Chentouf and Samira El Otmani

Regional Center of Agricultural Research of Tangier, National Institute of Agricultural Research, Avenue Ennasr, BP 415 Rabat Principale, Rabat 10090, Morocco
chebli.inra@gmail.com

Abstract

This study aimed to evaluate the seasonal feeding behavior of local goat kids browsing Mediterranean forest pasture located in Bouhachem Natural Park. The direct observation method was used to estimate, the diet composition and dry matter intake (DMI) of local goat kids during three grazing seasons (spring, summer, and fall). In addition, the palatability of plant species was determined. For this, eight local goat kids were selected to conduct this study. They were observed during three consecutive grazing days of each studied season. According to the results, Cistus and Quercus species are considered among the most palatable plant species for goat kids during the two grazing seasons of summer and fall. The DMI of goat kids was estimated at 230, 570, and 894 g DM/day during spring, summer, and fall, respectively. During spring, the diet of goat kids was composed of 63% herbaceous, 32% shrub, and 5% tree species. For the summer and fall, their diet was composed of more than 80% of woody species. The results underline the high adaptability and ability of goat kids to select a woody species across seasons. The outcomes of this study could be used as a first guide to understand the feeding behavior of goat kids browsing forest rangeland.

Key words: diet composition, dry matter intake, grazing goat kids, palatability, plant species, pasture

Introduction

In the Southern Mediterranean region, forest rangelands represent an important source of forage for domestic animals, mainly goats. The mechanism of goat feeding behavior and diet selection is quite complex (Morand-Fehr 2003). Goats are distinguished by their particular feeding behavior compared to cattle and sheep; they are considered as selective animals (Sanon et al 2007). Their grazing behavior is widely studied in Eastern (Aharon et al 2007; Glasser et al 2012; Koluman et al 2016), Northern (Meuret et al 1985; Mancilla-Leytón et al 2013; Manousidis et al 2016), and Southern (Chebli et al 2022a) Mediterranean Forest rangelands. The increased adaptability of goats has been assessed in many types of Mediterranean ecosystems and harsh environment (Manousidis et al 2016; Chebli et al 2020; El Otmani et al 2021). Unfortunately, the feeding behavior of local goat kids is less understood.

The assessment of the browsing behavior of goat kids in the Mediterranean forest of Northern Morocco such as natural parks is of great interest. The Bouhachem Natural Park, concerned by this research activity, is a regional natural park located around the Bouhachem Mountain in the Southern Mediterranean region of Northern Morocco. This inhabited rural territory was chosen thanks to its remarkable natural, landscape, and cultural entity and because of its high contribution to the goats’ diet.

To have knowledge about the goat kids feeding behavior such palatability and diet composition, which vary along the browsing season, is quite essential for developing grazing strategies in order to enhance their performance. In this context, this study was therefore undertaken to evaluate the browsing behavior of local goat kids during three grazing seasons in a forest rangeland located in Northern Morocco.

Material and methods

Experimental study area

This study was carried out in a forest rangeland named Tariya (35° 08'N; 5° 20' W; 1010 m a.s.l) which is a part of Bouhachem Natural Park, province of Chefchaouen (Photo 1). The climate is Mediterranean; it is hyper-humid with a cold winter ranging from 3 to 14 °C and stormy rains, and a hot summer varying in temperature between 18 and 38 °C. Thanks to the rainfall which reaches an amount of 1000–1400 mm per year, Bouhachem Natural Park is considered as one of the wettest areas in Morocco. This area has forest formations that extend over an area of 33,000 ha which covers 45% of the park's territory. These formations contain a very rich animal and forest heritage. The study area is characterized by the presence of all types of vegetation strata (tree, shrub, and herbaceous) largely dominated by oak species (Quercus spp.). The studied forest pasture was chosen based on its representativeness in relation to the different regional silvopastoral facies, the farmer availability, and its assurance to participate to this study to guarantee the good progress of the measurements in the field.

For animal production, the study area is browsed mainly by goats. Their number is about 45 heads/flock, with a maximum of 60 and a minimum of 24 heads. The goat herd is mainly composed of local goats’ population, which are more adapted to the mountainous landscape and vegetation type.

Browsing behavior measurement

A representative flock of 55 local population adult goats was observed after the kidding period to monitor foraging behavior of their kids. Before the animal behavior observations in the pasture, a three-day familiarization period for observers was needed to accustom the flock to the presence of observers (Chebli et al 2020). The success of the familiarization procedure makes measurement and selected plant species identification possible. As reported by Perevolotsky et al (1998), grazing behavior is not affected by the observer’s presence after a familiarization period.

Photo 1. Goats browsing in a forest rangeland of Bouhachem Natural Park (Northern Morocco) © Chebli

Direct observation was used as a method to evaluate the foraging behavior of goat kids after weaning and to estimate their bite rate (BR, n bites/min) on each selected pastoral species (Chebli et al 2022b). The measurements were undertaken during the three grazing seasons (spring, summer, and fall) of the studied year. Direct observation was concerned all goat kids that the farmer made sure to keep with the flock and have approximately the same ages. In order to ensure a cash flow to meet the needs of the herder family, the rest of the goat kids was sold at the local market after one month of their birth (n=34). The time lag of kidding dates and farmer decision to kept less than 10 goat kids, explain the number of the observed local goat kids (n=8). The experimental goat kids were identified and weighed at the beginning of the experiment and the end of each studied season at the typical ages of 3, 6, and 9 months old. Kids were weighed, fasting, in the shed before going out on the studied forest rangeland on a scale with a precision of 10 g.

Each studied season corresponds approximatively to one homogenous group of goat kids in term of age (spring: 3 months; summer: 6 months; fall: 9 months), liveweight (LW) (spring: 7 ± 1.3 kg; summer: 13 ± 2.2 kg; fall: 25 ± 3.5 kg), respectively, and sex (male). The same goat kids were observed during three consecutive grazing days of each studied season.

For the experimentation, continuous bite observations were performed over the entire grazing days. Data were collected over 10-min snapshots by focal-goat kid sampling. During grazing, observers recorded the botanic composition and the number of bites on each consumed plant species. To estimate the bite weight (BW), the hand-plucked simulation method was used as described by Cook (1964). One hundred hand-plucked simulations per consumed part of plant species were collected separately in paper bags, dried in an oven at 40 °C to constant weight, and weighed to obtain the average mass dry matter per bite. The hand plucked simulation of bites were performed during each age category of the observed goat kids. The intake rate (IR, g DM/min) was expressed as the product of BR and BW. Diet composition (DC, %) was reported as the percentage of each consumed species in the diet (Chebli et al 2020). The daily dry matter intake (DMI, g/kg LW ^0.75) on the studied rangeland was calculated as the product of the average IR in accordance with the daily grazing (eating) time, considering the seasonal variations in LW (Chebli et al 2022b).

Statistical Analysis

Data were analyzed using SAS software (SAS Inst. Cary, NC, USA). Before analysis, data expressed in percentage were arcsine-square root transformed to normalize the distribution (Steel and Torrie 1980). Feeding behavior data were analyzed according to PROC MIXED procedure with the daily observations on each goat kid as an experimental unit. For all analyses, the significance level was declared at p < 0.05. In case of significant effect, means were compared using the Tukey’s test.

Results and discussion

Botanical composition of pasture

In the studied pasture, cork oak trees (Quercus suber) dominate the forest rangeland. The European olive (Olea europea var. sylvestris) is particularly settling in the scrublands and degraded parts of the forest rangeland. For shrubs, it is mainly composed of strawberry tree (Arbutus unedo), spiny broom (Calicotome villosa), Cistus species (inclusive of wrinkle-leaved (C. crispus), Montpellier (C. monspeliensis), and sage-leaved (C. salviifolius) rockroses), tree heath (Erica arborea), topped lavender (Lavandula stoechas), common myrtle (Myrtus communis), broad-leaved phillyrea (Phillyrea media), lentisk (Pistacia lentiscus), kermes oak (Quercus coccifera), and elm-leaf blackberry (Rubus ulmifolius). These listed plant species are the more selected forage by goat in the forest rangeland of Northern Morocco (Chebli et al 2022a).

Herd management

In the studied forest pasture, the herder manages himself the goats. In general, herder starts their working day by a morning milking goat. The collected milk is mainly intended for own consumption (less than 1.5 liters during the lactation period), and the surplus is transformed into cheese and butter. The tasks as milking goats and milk processing are meted to women. These tasks are performed by the herder wife or by one of these older daughters, usually the eldest. Overall, the kidding period is concentrated during the period of January to April. From birth until 15 days old, goat kids are kept at the goat shed under daily supervision by one of the breeder's family members, often the youngest children. During this period, the feed source for goat kids is assured only by goat milk or by bottle-feeding for those which are born with health or growth problems. After 15 days and until the first month of ages, every morning the goat kids are released from the shed and kept around the farm for their grazing initiation. From the first to the third month of age, they start to go with the adults to the pasture. During this period, their feeding is composed on different plants species mainly herbaceous group. After three months of age, goat kids become more adapted to their environment and enlarge their diet selection depending on the grazing season and area (Figure 1).

Figure 1. Diet Management and composition of local goat kids browsing a forest rangeland of Bouhachem National Park (Northern Morocco) from birth to 9 months old

Pastoral species palatability

Palatability is the corollary of the animal's appetite for the selected forage. It was determined by direct observation of goat kids feeding behavior on the studied pasture and has complemented by interviews with the several herders of the studied forest rangeland. In general, goats tolerate the bitter taste of certain plants that contain alkaloids and tannins, and they are less sensitive to their toxicity (Chebli et al 2021a). Table 1 illustrates the palatability degree of the main pastoral species in the forest rangeland of Bouhachem National Park. The difference in palatability is mainly due to the seasonal variation in the chemical composition of the plant species selected by the animal, to the selected part of the plant, where the young shoots are more appreciated especially for kids, and to the forage availability on the rangelands (Chebli et al 2020).

For the degree of plant species' palatability, the measurements were based on the seasonal selection of each plant species. In this study, a rating scale in four categories was used: highly palatable (HP), moderately palatable (MP), poorly palatable (PP), and finally non-palatable (NP).

According to the direct observation and herder interviews, Cistus spp. (inclusive of C. crispus, C. monspeliensis and C. salviifolius) and Quercus spp. (inclusive of Q. coccifera, Q. ilex and Q. suber) are considered among the plant species more palatable for goat kids during the two grazing seasons of summer and fall. According to Chebli et al (2020), the palatability degree depends mainly on seasons and on the availability of each plant species on the pasture.

With the continued degradation of forest, due to deforestation practices, such as delimbing and clearing for the establishment of new crops, grazing areas continue to decrease leading to increased animal stoking rates on the pasture. This overgrazing causes an overexploitation of the most palatable pastoral resources and the appearance of non-palatable species (Chebli et al 2018b).

Foraging behavior of goat kids

Figure 2 displays the seasonal variation of the intake rate of goat kids browsing in the studied forest rangeland. Kids spent about 3 hours of their feeding duration on grazing (eating) during each season. The highest value of intake rate was recorded during summer (about 4.4 g DM/min).

The data of the seasonal DMI (g DM/day) of goat kids browsing a forest rangeland of Bouhachem Natural Park in Northern Morocco are presented in Figure 3. The estimated DMI of goat kids was 230, 570, and 894 g DM / day during spring, summer, and fall, respectively, corresponding to 3.00, 2.40, and 2.80% of their LW, respectively (p<0.05).

If assessed to their respective metabolic weights (LW^0.75), the estimated DMI during browsing time was 53.4 ± 5.8, 78.9 ± 9.2, and 80 ± 7.6 g DM/kg LW^0.75, respectively (p<0.05). In heterogeneous vegetation of Merida (Mexico), the daily DMI of local kids' goats (19 ± 3 kg LW) browsing was estimated at 475 ± 147 g DM/day corresponding to (52.5 ± 5.1 g DM/kg LW^0.75; Gonzalez-Pech et al 2021).

Figure 2. Seasonal intake rate (IR; g DM/min) of goat kids browsing a forest rangeland of Bouhachem Natural Park (Northern Morocco). a-c Values with different letters are significantly different (p < 0.05)	Figure 3. Seasonal dry matter intake (DMI; g DM/day) of goat kids browsing a forest rangeland of Bouhachem Natural Park (Northern Morocco). a-c Values with different letters are significantly different (p < 0.05)

Figure 4 represents the seasonal diet composition of goat kids browsing a forest rangeland of Bouhachem Natural Park in Northern Morocco. During spring, the diet of goat kids is composed of 63% herbaceous, 32% shrub, and 5% tree species. For trees, Q. suber represented the most ingested plant species. Among shrubs, goats consume significant amounts of C. monspeliensis and C. salviifolius.

During summer, the diet of goat kids is composed by less than 19% of herbaceous species. In this season, their diet is mostly composed by shrub species estimated at 72%. Among shrub species, goat kids prefer especially the three species of Cistus spp. and Q. coccifera. For tree species, Q. suber is always the most consumed with a contribution to the diet rate of 8% while O. europaea contributed only by 1% of the ingested plant species.

In the fall, the diet of the experimental goat kids is composed by 67% of shrub, 23% of tree and 10% of herbaceous species. Among shrubs, Q. coccifera is the most selected with 12% followed byA. unedo, P. lentiscus and E. arborea. For trees,Q. suber was the most consumed diet with 17% while O. europea presents only 6%.

Figure 4. Seasonal diet composition (%) of goat kids browsing a forest rangeland of Bouhachem Natural Park in Northern Morocco. From the inside to the outside in order of spring, summer, and fall

Conclusions

• This study highlights the seasonal changes in browsing behavior of local goat kids in the Mediterranean forest rangeland of Northern Morocco.
• The feeding behavior of goat kids on Bouhachem Natural Park indicates that woody species constitute their preferred feed.
• These results could be used as the first guide for future studies about feeding behavior of browsing goat kids.

Acknowledgements

The Provincial Department of Agriculture (DPA) of Chefchaouen (02/DPA.50/2017) and Regional Center of Agricultural Research (CRRA) of Tangier, National Institute of Agricultural Research (INRA, Morocco) funded this study. Authors thanks the herders of Bouhachem Natural Park for their useful help and support.

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