5. RESEARCH

5.1 Research in nutrition

Undernutrition is one of the main limiting factors for sheep production in Morocco with deficiencies in energy, nitrogen, minerals and vitamins. Shortage of feed and/or the low quality of available feed are the main reasons. Consequently, during the first 10 years research on sheep nutrition has focused on two aspects:

A substantial portion of the sheep nutrition research programme has been supported by the Small Ruminants Collaborative Research Support Programme (SR-CRSP) which was initiated in Morocco in 1982.

5.1.1 Research on stubble and straw

5.1.1.1 Stubble

Research on stubble has focused on several aspects:

1. Stubble biomass and its fluctuation with cereal species (barley, hard wheat, soft wheat) and period of grazing.
2. Chemical composition and digestibility of feed of sheep grazing stubble, with particular reference to stocking rate, period of grazing and physiological stage of ewes.
3. Sheep intake under stubble grazing.
4. Supplementation of grazing ewes during breeding and gestation phases.

Preliminary results on stubble have been recently published (Guessous et al., 1987; Outmani et al., 1988).

5.1.1.2 Straw

Improvement of straw nutritive value through chemical treatment is the objective of this programme. As anhydrous ammonia is not marketed in Morocco, research has been oriented toward urea treatment. Trials started in 1987 and preliminary results were reported by Benslimane (1988).

5.1.2 Research on by-products and forages

5.1.2.1 By-products

Research has so far focused on four by-products: waste palm dates and sugar beet, citrus and caroub pulp. The first two feeds are largely used by sheep and cattle while the last two continue to be partly exported. These by-products have in common a high energy value and a low nitrogen content.

Research conducted has paid attention to:

Available information has been summarized by Rihani, Guessous and El Fadili, (1985), Rihani, Guessous and Berrami (1988) and by Guessous, El Hi1all and Johnson (1988).

5.1.2.2 Alfalfa

Under prevailing production systems, sheep depend very little on cultivated forages except in the oasis zones where alfalfa represents the major feed.

Alfalfa yield, composition and digestibility were investigated in 1982 and 1983 in a research station in the Ziz valley. Farm samples were later collected in Ziz and Draa.

Collected information has led to recommendations concerning alfalfa management and utilization and to adapted tables of feed composition (Guessous et al, 1985).

5.1.3 Nutrient requirements of local breeds

A few trials have been conducted to estimate nutrient requirements of Moroccan local breeds.

Energy maintenance requirements for Timahdit, D'Man and crossbred males have been estimated by Kabbali (1986). Energy growth requirements for lambs on normal or compensatory growth plans have also been investigated by the same author. Other experiments attempted to describe milk production and quality for suckling ewes and to establish regressions between milk consumed and average daily gain of lambs (Zari, 1979).

5.2 Research in breeding

Introduction

Even though some experiments were carried out during the colonization period, sheep breeding research in Morocco is very recent and started in the 1970s. The main purpose was the characterization of native breeds with regard to their standard and performance. However, these studies did not cover all native breeds, but only those numerically important and with a good potential. After this first step, some selection and crossbreeding experiments followed.

This chapter will first report results obtained by research workers concerning performance of different breeds and then present the findings of recent selection and crossbreeding experiments.

5.2.1 Reproduction and production performance

Among the Moroccan breeds, the D'Man has been the most studied mainly owing to its exceptional reproductive potential.

5.2.1.1 Age at first lambing

Results obtained from the D'Man breed either in the field or on experimental stations are reported in Table 5.1 These results show that D'Man females lamb for the first time between 12 to 15 months. In Tabouassamt station at Rissani (Ziz valley), Bouix, Kadiri and Chari (1974) reported that some ewe lambs lambed accidentally at 8 months of age, indicating that the D'Man ewe is already cycling at 3 months old.

In the experiment carried out in Skoura station at Ouarzazate, Harrouni (1977) found that the first oestrus in the D'Man breed occurred between 132 and 160 days after birth. Age at puberty seems to be affected by season of birth. In comparing ewe lambs born in July and November-December at the Gharb station, Lahlou-Kassi (1980) showed that the former reached puberty between 110 and 220 days of age, whereas the latter reached it between 169 and 292 days after birth.

Table 5.1: Age at first lambing (days) of D'Man ewes

Age at first lambing of other native breeds generally varies between 20 and 24 months (Ben Lakhal, 1983). The main reason for this delay is that most lambings occur in November which do not allow ewe lambs to reach puberty the following sexual season, and hence their mating is postponed.

Comparing ram lambs of D'Man and Beni Ahsen breeds, Benseghir (1978) showed that the former reached puberty at 165 days of age, whereas the latter had not reached it at 252 days.

5.2.1.2 Post-partum anoestrus

Several authors reported that the ovarian activity of the D'Man breed takes on average 45 days after lambing (Bouix, Kadiri and Chari,1974;Harrouni, 1977; Khallouk, 1987). This exceptional performance allows D'Man ewes to be mated during lactation and to have two crops per year.

In an experiment carried out at the ENA station at Meknès, Raymond (1979) found that only 50 percent of Timahdite ewes were in heat 80 days after lambing.

5.2.1.3 Lambing interval

Except for D'Man ewes which have a short lambing interval of about 7 months (Bouix, Kadiri and Chari, 1974; Harrouni, 1977; Arif, 1978; El Fakir et al., 1979; Boutgayout, 1980; Khallouk, 1987), all the other local breeds have a lambing interval of about 9 months.

5.2.1.4 Sexual season

The sexual season is very limited for all native breeds, but the D'Man. For the Timahdite breed, Marie and Lahlou-Kassi (1977) showed, from an experiment carried out in the Gharb station, that the sexual season lasted average 6.6 months, while Dkhissi (1978) found that for Beni Ahsen ewes it lasted 9 months. For these breeds, the sexual season usually starts at the end of May. On the other hand, ovarian activity of the D'Man breed stretches over all the year with a slight decline in March (Boutgayout, 1980; Lahlou-Kassi, 1980).

5.2.1.5 Length of oestrus cycle and duration of oestrus

The average length of the oestrus cycle of D'Man ewes is 17 days (Harrouni, 1977) and 18 days (Lahlou-Kassi, 1980). Likewise, for Timahdite ewes, the length of the oestrus cycle was found to be 18.2 days (Marie and Lahlou-Kassi, 1977) and 17 days (Raymond, 1979).

On the other hand, the duration of oestrus is about 30 hours and seems similar for both D'Man (Harrouni, 1977) and Timahdite (Marie and Lahlou-Kassi, 1977).

5.2.1.6 Fertility

Results obtained from different breeds either in the field or in experimental stations showed that fertility of native breeds is in general satisfactory and similar (90-95 percent) (Lamraoui, 1979; Boujenane et al., 1982; Ben Lakhal, 1983). In the study by Bouix, Kadiri and Chari, (1974), fertility was found to be 100 percent for D'Man ewe lambs of 1 year old.

In addition, effect of age of ewes on fertility was studied by Ben Lakhal (1983) and Chafik (1986). In these studies, fertility increased with the ewe's age.

The effect of breed of ram on fertility of ewes was studied by Lahlou-Kassi et al. (1988) at the Tadla station. In this experiment, Sardi ewes were mated either to Sardi or D'Man rams. Fertility of ewes mated to D'Man rams was significantly higher than that of ewes mated to Sardi rams (Lahlou-Kassi et al., 1988).

Moreover, fertility is influenced by the season of mating. In the experiment by Bouix et al . (1977), the fertility of D'Man ewes mated in summer was higher than that of ewes mated in autumn.

5.2.1.7 Prolificacy

Several studies showed clearly that the D'Man is the most prolific breed in Morocco. The lowest litter size (1.58) reported for this breed was found by Arif (1978) in a survey carried out in the cradle of the breed at Draa valley, and the highest (2.67) was reported by Bouix, Kadiri and Chari, (1974). From an analysis of 1 852 performances gathered in two stations at Ziz, Khallouk (1987) found that litters of 1, 2, 3, 4, 5, 6 and 7 lambs represented 26.4, 43.6, 23.5, 5.4, 0.81, 0.16 and 0.06 percent respectively with an average of 2.09.

The average litter size of Timahdite, Sardi, Beni Guil and Beni Ahsen is low and varies from 1 to 1.10 (Bourbouze, 1974; Lamraoui, 1979; Bennouna, 1980; Laghlabi, 1980; Zari, 1979; Ben Lakhal, 1983). However, in the experiment carried out at the Tadla station, Chafik (1986) showed that under good management conditions, the litter size of Sardi ewes was 1.20. The same result was obtained by Lamraoui (1979) for Beni Ahsen ewes.

The effects of environmental factors on litter size were investigated by Ben Lakhal (1983), Chafik (1986), Khallouk (1987) and Nacir (1987). They concluded that age of ewes and year of lambing were the most important factors.

5.2.1.8 Ovulation rate

Laparotomy and laparoscopy techniques have been used in the Gharb and Tadla stations to assess the ovulation rate of some breeds. In the experiment carried out in the Gharb station, Lahlou-Kassi and Marie (1981) found that the ovulation rate of D'Man ewes was 2.50.

In comparing the ovulation rate of D'Man and Sardi ewes raised in the Tadla station, Boujenane et al. (1988a) found averages of 1.23 and 1.32, and 2.56 and 3.21 for Sardi and D'Man respectively. In addition, they reported that the ovulation rate of Sardi ewes varied from 1 to 3, whereas that of D'Man ewes ranged from 1 to 8.

5.2.1.9 Lamb survival

Available information on lamb survival of various sheep breeds shows that 15 to 20 percent of lambs die before weaning at 90 days (Bouamrani, 1977; Lamraoui, 1979; Bennouna, 1980; Laghlabi, 1980; Zari, 1979; Ben Lakhal, 1983; Chikhi, 1986). However, lamb survival of the D'Man breed is lower mainly because of their light birth weight which is the result of the higher litter size (Bouix, Kadiri and Chari, 1974; Arif, 1978; Boutgayout, 1980; Ezzahiri, Benazzou and Ben Lakhal, 1980). In the experiment carried out at the ENA station at Meknès, Fergani (1980) reported that the lamb mortality of the D'Man breed was 0, 16, 26 and 53 percent for single, twin, triplet and quadruplet litters respectively.

a) Milk production

Milk yield and composition have been estimated for the most important native breeds. However, results reported showed that milk yield varied according to method of estimation and length of lactation.

In two different investigations carried out in the Gharb station, Kabbali (1976) and Bouila (1977) compared milk yield and composition of Timahdite and Beni Ahsen ewes. The results of these studies showed that Timahdite ewes produced more and had a higher fat percentage than Beni Ahsen ewes.

Using the method of partial suckling, Sefiani (1980) showed in an experiment carried out at the Gharb station that milk yield and composition of Sardi ewes were higher than those of Beni Gull females.

Battar (1983) studied the milk yield of Timahdite, Beni Ahsen, Sardi and Beni Guil ewes rearing single lambs. Milk yield estimated by weighing lambs before and after suckling during 12 weeks was 60.5, 57.9, 57.4 and 56.1 kg for Beni Hsen, Timahdite, Sardi and Beni Guil respectively (Table 5.2).

Milk production of D'Man ewes was studied by Behba (1975), El Kabbach (1977), Fergani (1980) and Asserrhine (1984). The authors found that it was slightly low.

Table 5.2 Milk yield and composition of native breed ewes

(Batter, 1983)

b) Growth traits

Results of growth performance are the most reported in the Moroccan literature related to sheep breeding (Boujenane et al., 1982). However, the majority of the authors were interested in pre-weaning growth and only few had extended their study beyond weaning.

From the body of results given in Table 5.3, it appears that average birth weight of Timahdite, Sardi, Beni Ahsen and Beni Guil lambs was 3.5 kg, whereas that of D'Man lambs was lower and about 2.6 kg.

In addition, body weights at 30 and 90 days were similar for all breeds but D'Man, and were on average equal to 8.5 kg and 17.5 kg respectively. The weight of D'Man lambs at 30 and 90 days was about 6 kg and 15 kg respectively.

Average daily gains were satisfactory and ranged on average between 150 and 200 from birth to 30 days, and between 100 to 150 g from 30 to 90 days. Nevertheless, it seems that lambs of the Timahdite, Beni Hsen and Sardi breeds gained slightly more than those of the Beni Guil and D'Man breeds.

The study of post-weaning body weights carried out at the Tadla station showed that the significant difference in pre-weaning growth traits between Sardi and D'Man lambs stopped at 6 and 12 months old (Chikhi, 1986; Nacir, 1987).

Table 5.3 Growth traits of native breed lambs

Several authors studied the effect of environmental factors on growth traits and showed that weight of males exceeded that of females at any age. In addition, lambs from young dams were lighter than those from mature ewes. Lambs born as singles grew faster than those born or reared as multiples (Bourbouze, 1974; Bouix et al., 1977; Lamraoui, 1979; Essaidi, 1984; Chikhi, 1986; Nacir, 1987).

c) Wool production

Wool characteristics have been studied since 1985. Two studies were conducted by El Hmamsi (1986) and Laidouni (1986) in which they compared fleece weight and wool characteristics of various breeds. Results presented in Table 5.4 show that the highest fleece weight was performed by the Beni Ahsen breed, while the D'Man breed produced the lightest fleeces. The average wool yield was similar for all breeds and equal to 60 percent. In addition, Laidouni (1986) reported that the finest wool fibres were produced by the Sardi breed and the coarsest wool was found in the D'Man breed.

Table 5.4 Fleece weight and wool characteristics

(Laidouni, 1986)

5.2.2 Improvement through purebreeding and selection

In 1981, the Livestock Service of the Ministry of Agriculture proposed a programme for sheep improvement. This programme defined the standards of the Sardi, Beni Guil, Timahdite and D'Man breeds, and divided the Moroccan territory into areas of purebreeding and crossbreeding.

According to this programme, the areas of purebreeding correspond to the cradles of the most important breeds. Thus, the eastern hills, western hills, Draa and Ziz valleys and middle Atlas and vicinity are the areas where the Beni Guil, Sardi, D'Man and Timahdite breeds respectively must be raised as purebred. Crossbreeding, either between native breeds or between exotic and native breeds, is only allowed outside of these areas. The programme also suggests some exotic breeds to be used as ram breeds. These are Ile de France, Berrichon de Cher, Suffolk, Merinos Précoce, Causse du Lot and Noir du Velay. In order to provide rams to sheep breeders, flocks of exotic purebreeds are raised in some crossbreeding areas.

In addition, selection is attempted in purebred flocks. Every year, a commission of 4 to 5 experts visits some flocks and does some selection. However, animals are not judged on their genetic values, but only on their phenotypic performance according to criteria such as:

Selected animals are ranked in four classes: super, first, second and third category, and entered in the Moroccan Flock Book. The number of rams entered in the Flock Book since 1982 is indicated in Table 5.5

Table 5.5 Number of rams entered in the Flock Book

(Benlakhal and Kabbaj, 1987)

Furthermore, inside the cradle of each breed, there are one or two stations in which a nucleus flock is maintained for breed selection and to safeguard the breed. At present, the Ministry of Agriculture has seven stations:

In addition to these stations, other purebred flocks are raised in the experimental farms (Gharb and Tadla) of Hassan II Agronomy and Veterinary Institute, National School of Agriculture and National Agronomy Research Institute.

To our knowledge, only two selection experiments have been carried out on the D'Man breed in the Tabouassamt-Achouria and Skoura stations by Bouix, Kadiri and Chari, (1974) and Ben Lakhal, Benazzou and Ezzahiri, (1980) respectively. However, the improvement observed in these flocks was not more than the result of culling the less productive animals in the initial flock. Thus, Bouix, Kadiri and Chari (1974) reported an improvement in litter size of 0.20 to 0.25 lambs born after one year of selection at spring lambing, and 0.40 lambs at autumn lambing. In the study of Ben Lakhal, Benazzou and Ezzahiri (1980), selection was aimed at the improvement of body weight. Animals were selected on their weight at 6 months and on conformation. Data were analysed for each lambing season within sex and type of birth, and animals were selected from each class. Results of this study, carried out from 1974 to 1980, were an increase of 0.5 and 4.1 kg in birth weight and weight at 90 days respectively, and an improvement of 0.70 and 0.39 lambs born from young and mature ewes respectively.

Even though genetic parameters are necessary for selection programmes, only those of some traits in D'Man and Sardi breeds were estimated. Tables 5.6, 5.7, 5.8 and 5.9 show heritability and repeatability estimates for some reproduction and growth traits. From these estimates, it appears that heritability of reproduction traits is very low, which indicates that selection will lead to low genetic gain. On the other hand, their repeatability was also small which indicates that culling must be based on more than one performance.

Assuming that growth traits were dam characters, Nacir (1987) showed that repeatability of body weights increased as the age of lamb increased.

Genetic and phenotypic relationships between reproduction traits in the D'Man breed and growth traits in the Sardi and D'Man breeds were estimated by Boujenane, Khallouk and Kerfal (1988b) and Nacir (1987) respectively Table 5.6 and Table 5.9.

Table 5.6: Estimation of heritability, phenotypic and genetic
correlations (1)

(Boujenane, Khallonk and Kerfal 1988b)

¹ Heritability on diagonal, phenotypic correlations above diagonal and genetic correlations below diagonal.

Table 5.7: Repeatability estimates of reproduction traits

(Nacir, 1987)

Table 5.8: Repeatability estimates of body weights

(Nacir, 1987)

Table 5.9: Phenotypic correlations between body traits of Sardi (S) and
D'Man (D)

(Nacir, 1987)

5.2.3 Improvement through crossbreeding

Crossbreeding experiments carried out in different stations involved either native breeds or exotic and native breeds.

In a diallel cross involving Timahdite, Beni Ahsen, Beni Guil, Sardi and D'Man breeds, Chouli and Oukelmoun (1983) reported that lambs sired by Beni Ahsen or Sardi rams had higher body weight at any age and better average daily gain than lambs of other breeds of ram (Table 5.10). In addition, they reported that among ram lambs slaughtered at 70 to 90 percent of mature weight, Beni Guil and D'Man purebreds had the highest fat deposition and mesenteric fat, whereas crossbred lambs sired by Beni Ahsen or Sardi had the fattest carcasses. This study also showed that Beni Guil and Sardi purebred lambs and Beni Ahsen x Beni Guil, Beni Ahsen x Sardi and Sardi x Beni Guil were the most well muscled.

In the crossbreeding experiment involving Sardi and D'Man breeds carried out in Tadla station, Boujenane et al. (unpublished data) showed that body weight of lambs of Sardi, 3/4S 1/4D, Fl, F2, 3/4D 1/4S and D'Man genotypes decreased as the percentage of D'Man genes increased. Individual and maternal heterosis were -6.6 percent and 2.1 percent, -3.0 percent and 1.3 percent and -0.9 percent and 5.8 percent for birth weight, weight at 30 days and weight at 90 days respectively.

The comparison of Fl ewes to their parental Sardi and D'Man breeds showed that the heterosis of litter size and ovulation rate was 1.4 percent and -0.5 percent respectively (Boujenane et al., 1988a).

Milk production of D'Man and D'Man x Timahdite (DxT) ewes was studied by Asserrhine (1984). The results of this study showed that D'Man ewes rearing singles, twins or triplets produced, in 13 weeks of lactation, 78, 89 and 113 kg of milk respectively, whereas (DxT) Fl ewes rearing singles and twins produced 65 and 80 kg respectively. In addition, fat percentage was 3.77 and 4.45 for D'Man and (DxT) Fl ewes respectively.

Table 5.10: Body weights and carcass characteristics of native breeds and
their crossbred lambs

(Chouli and Oukelmoun, 1983)

In the experiment carried out in a well-managed private flock at Settat, Tampier (1977) compared growth performance of Beni Guil purebred lambs and Ile de France x Beni Guil crossbred lambs. The results of this study showed that purebred and crossbred lambs were 18.2 kg and 24.2 kg at 90 days of age respectively. The average daily gain at 10-30 days and 30-90 days was 156 g and 170 g respectively for Beni Guil lambs, and 228 g and 229 g respectively for Fl lambs.

5.3 Research in range management

5.3.1 History of range management research in Morocco

Research in range management is quite recent in Morocco. Before 1968 rangelands attracted primarily foresters and European plant ecologists. Most of these scientists were active researchers in Moroccan institutions such as the Phytoecological Station of the National Institute of Agricultural Research (INRA), the Cherifian Institute of Science (ISC) and the Forest Experiment Station of the Direction des Eaux et Forêts. During this period, attention was focused exclusively on the plant component of rangelands, while grazing activity was not investigated. Research performed within this period consisted primarily of vegetation inventory, mapping, and the examination of plant community/environment interactions. This work led to the establishment of a large-scale vegetation map of Morocco (Emberger, 1939) complemented by smaller scale maps for some Moroccan regions (Ionesco, 1965; Ionesco and Stefaneosco, 1967). Investigations on relationships between environmental variables, such as climate and soil, and plant communities were also published by Brignon and Sauvage (1962), and Pujos (1962), and Negre (1959).

5.3.2 Present range management research structure in Morocco

Despite the magnitude of the rangeland problems and the tremendous opportunities for research needed to solve these problems, research and funding are still in their early stages. At present, research results related to management of range resources come mostly from researchers in educational institutions, mainly the Institute of Agronomy and Veterinary Medicine, Hassan II (INAV), the National School of Agriculture (ENA), and the National School of Forestry (ENFI). A few other scientists concerned with research on plant physiology, ecology and taxonomy hold positions in various colleges of science located in Marrakech, Rabat, Fès and Oujda, in ISC and in INRA.

Research accomplished so far in the field of range management has been implemented primarily at four experiment stations located in the middle Atlas region (Sidi Aïssa and Timahdit), in the arid high plateau (Ain Beni Mathar), and in the Moulouya (Talsinnt and Boumia).

The topics covered by this research include vegetation inventory, determination of productivity and carrying capacity of different range sites, studies on feeding behaviour of sheep and goats, and on the feasibility of different management practices and supplementation schemes.

Data on seasonal and yearly variations of productivity and nutritive value of Artemisia herba alba, Stipa tenacissima and various grassland sites of the middle Atlas mountains have been collected over the last ten years at the Timahdit, Sidi Aïssa, Boumia, Talsinnt and Ain Beni Mathar stations. Diet composition and diet quality of sheep and goats as affected by season of use and stocking rate have been examined at the Timahdit, Sidi Aïssa and Ain Beni Mathar stations. Vegetation response to different grazing intensities was also investigated at Timahdit and Ain Beni Mathar stations. The performance of introduced forage species and the effects of fertilizer applications were tested at the Timahdit and Sidi Aïssa stations as well as at other sites throughout the country. Basic synecological and ecophysiological studies, including a study of the physionomy, structure and distribution of the flora in the southern slopes of the high Atlas mountains and an investigation on Artemisia herba alba population dynamics, as affected by environment and management, were also implemented.

Studies concerning revegetation of forested grazing lands, the effect of thinning of oak-woodland tree cover on production of wood and forage products, the response of native vegetation to grazing treatments, and the effect of various land use treatments on watershed values have been conducted on forested lands.

Forage selection work is continuing for both pasture and rangeland situations, while sociological studies have always accompanied rangeland. research and development efforts in Morocco.