Goat genetic resources in Madagascar

Introduction

Animal genetic resources are an invaluable global asset. They provide around 30% of human needs in terms of food and agriculture. The use of these resources enables, among other things, the improvement of productivity, the quality of livestock products and the maintenance of animal health [1,2] . The diversity of animal genetic resources is a source of adaptability and resilience in the face of climate change, emerging diseases, constraints in feed supply, and changes in market demand [3][4][5] . Indeed, many indigenous breeds have particular adaptive traits: resistance to disease, tolerance of the local climate, ability to accept poor-quality and reduced-quantity feeds [4,6] . It is also likely that they have a particular aptitude for transforming a poor, low-protein diet [6] . In addition, human activities are depleting the planet's biological diversity [7] . For thousands of years, breeders have exploited animals domesticated by their ancestors on a small, local scale for specialized uses [6] . Biological cycles were therefore stable, and food production could continue unabated [6] . However, the pressure exerted by the growing human population and its need for food is upsetting the balance of natural resources used [6] . Indeed, recent trends in livestock production systems in developing countries to satisfy the demand for animal products, such as the introduction and increased use of exotic animals or their semen, uncontrolled crossbreeding or the intensification of production systems, are leading to poor management of animal genetic resources [4] . These attitudes lead to the genetic erosion of local breeds, which could eventually lead to the complete disappearance of these genetic resources. If they were to disappear, opportunities for genetic improvement of the species would also be lost. Given this situation, efforts to promote the sustainable use of these animal genetic resources must be stepped up as a matter of urgency [4] .

International Journal of Advanced Biochemistry Research 2024; 8 (9): 883-893

Consequently, many countries are currently working to halt the erosion of their animal genetic resources by conserving their own resources [4] . In all regions of the world, livestock farming is an integral part of agriculture [8] . In regions characterized by extreme conditions unfavorable to agriculture, livestock is the only basis for human settlement [9] . In the case of goat farming, the livestock population has increased considerably since the 1960s, as climate change has limited the areas suitable for breeding [10] . In 2013, the world goat herd exceeded one billion head, an increase of over 34% since 2000 [11][12][13] . Africa is a major breeding area, accounting for a third of the world's goat population, with a greater distribution in the most arid regions [10,14] . In fact, the African goat population represents 41% of the world population, and currently stands at around 423 million goats [11] . Arid zones are characterized by a high degree of random variability in time and space of natural forage resources. As a result, goats have always been considered the animal best suited to these precarious production conditions. In addition to their contribution to covering protein (meat and milk proteins), energy (fats, milk lactose), vitamin and mineral requirements, goats are raised for savings and income generation purposes [8] . Indeed, in difficult regions such as southern Madagascar, to survive each time drought wipes out most of their crops, poor and vulnerable families have given in to selling a large proportion of their goats, which are less sensitive to irregular rainfall than agriculture. In addition to milk, goat farming offers other benefits to owners: it provides raw materials for the craft and leather industries (skins, leather, hair, etc.), meat for households and fertilizer for farmers [10,15] . In rural areas of developing countries, the contribution of goats is highly valued. Indeed, goats are extremely intelligent, highly agile and independent animals, with a high level of disease resistance, compared to other ruminant species [12] . Despite the importance of the goat sector in Africa, the erosion of genetic heritage is leading to the gradual disappearance of local goat breeds. The need to conserve these resources is therefore required in order to contribute to the conservation and maintenance of sustainable management [4] . However, in developing countries, animal genetic resources are made up of a multitude of often poorly characterized populations. In this review, we will attempt to draw up an inventory of these goat resources in Madagascar.

Domestic goat breeds and origins

The domestic goat or simply the goat does not belong to the primitive fauna of the large island and could not have been domesticated there [16] . In fact, the present-day goat, which belongs to the genus Capra aegagrus hircus, is a subspecies of Capra aegagrus domesticated from the wild goat (Capra aegagrus creticus -Schinz 1938 -Figure 1). It belongs to the animal family Bovidae and subfamily Caprinae. Wild goat: kri-kri or Capra aegagrus creticus [17] Goats were domesticated somewhere in the fertile crescent of the Middle East more than -10,000 years ago (Figure 2), and are among the first five farm animals domesticated by man [18][19][20][21] .

Fig 2:

Places and dates of domestication of the main domestic animals [22] Domesticated goats accompanied the first breeders, during their immigrations in the early (10,000-5,000 years BC) and late Neolithic (5,000-0 years) periods, in their quest for new territories in Asia, Europe and Africa (Figure 3). Goats are robust and enduring species. They constituted a mobile supply of milk and fresh meat during their travels [23,24] .

Fig 1:

(A) Expansion and diffusion of agriculture and animal husbandry during the early and late Neolithic periods [25] (B) Mesopotamian stone sculpture of a man carrying a domestic or wild goat (Louvre Museum)

Like all the indigenous goats (marronnes) of the Indian Ocean islands [16,26] on the route of the ancient navigators, Malagasy native goats could have been brought: either by Arab and Antalaotra navigators between the VI ème century and XIII ème century; or by Arab and African (Bantu) trading immigrants who were pastoral populations, taking advantage of the flourishing trade between the African coast and Madagascar [27][28][29] . Indeed, Arab navigators and the Antalaotra used goats as food during their voyages and/or during the long months of waiting for monsoon overturns aboard their dhows on the west coast of Madagascar [27,29,30] . Mixed with proto-Vezo, these new immigrants (Bantus and Arabs) contributed to the settlement of pastoralists in western and southern Madagascar [31] . Goat breeding is developing in these regions, with a wide range of phenotypic diversity [32] but they are generally well adapted to the harsh environment in which they must survive and reproduce [32,33] .

Goat herd and geographical location

In Madagascar, the goat herd continues to grow (Table 1; Figure 4). In 2012, goat breeding was estimated at around 2, 327, 270 head [34] . 2)

in order to obtain exhaustive information on existing breeds. [35] .

Goat breeds bred in Madagascar

Native Malagasy goats are made up of two very distinct ecotypes: the short-haired (Fohivolo goat) and the longhaired (Beroma goat) shown in Figure 5 [16,32] . In 1914 and 1924, Angora goats from Africa were introduced in the vicinity of the province of Tuléar, where they developed strongly [16] . In addition to the local population, there are also a number of imported goat breeds, such as the Alpine and Boer breeds [16] . , with horns [32] Their coats are highly variable, with 8/9 possible pigment patterns between black or eumelanic pigment (Figure 7) and red or phaeomelanic pigment (Figure 7) [32] . These coat colors are controlled by 13 genes, including the ASIP (Agouti Signaling Protein Gene), controlling these pigment patterns and other genes controlling variegation and pigment alterations [36] .

Fig 7:

The nine (09) pigment patterns in goats [37] However, the dominance of the pigment pattern eumelanin (locus agouti allele Aa: black and brown -Figure 8), Badger or buff (locus agouti allele Atb-Figure 8) and wild (locus agouti allele A+ -Figure 8) was observed [32] . What's more, these pigment patterns are sometimes hidden by variegations or alterations (Figure 8). alteration (Grey) [32] Biometrics To compare the biometric parameters of native Malagasy goats, the Substernal Gracility Index or SGI [38] and live weight estimation using the method of Traoré et al. [39] are used. On the one hand, the IGs is defined by the ratio between the substernal void (SSV) and the breast width (BW). On the other hand, SSV is equal to the difference between height at withers (HW) and BW (Formula 1). On the other hand, live weight is estimated using chest circumference (CC) and height at the withers (HW) measured with a master tape, according to the procedure described by Katongole's team [40] . A multiple linear regression equation established by Traoré's team [39] is then used to estimate the live weight of Malagasy goats (Formula 2). Formule 1:

If we consider the substernal gracility index (IGs=0.94 and 0.98 -less than 1 -Table 3), the two Malagasy ecotypes are among the Brevipedic goats like its cousin the Small East African (SEA goat). Indeed, these Malagasy goats have visible phenotypes very similar to SEA, but have higher biometric variables (Table 3). Using live weight estimates, both Malagasy ecotypes appear heavier (Table 3) than their SEA cousin (adult male: 30-40 kg and female: 25-30 kg).

Comparing the two Malagasy ecotypes, Fohivolo goats appear taller and heavier than Beroma goats. Compared with the average weight and height at withers (HW) of Beroma goats, those of Fohivolo are generally higher. Nevertheless, Beroma goats have longer bodies than Fohivolo (Table 3). The values of primarity indices in segregation with respect to "visible effect loci" (IPa values of s=1.00) and agouti loci (IPa=0.88), reflect well the primary or traditional population status of native Malagasy goats [42] . It seems that no selection has been made by Malagasy native goat breeders since their introduction to Madagascar. [43] *LB: Length of body; HW: Height at withers; CC: Circumference of chest, BW: breast width (BW); * Substernal gracility index or IGs=(HW-BW)/BW: -if GIs≤ 1 == > Goat brevipedes, -if GIs ≥ 1.5 == > Logopedic goat.

Malagasy Angora goat Morphology and geographical distribution

Angora goats (Capra hircus angoremis) are native to Asia Minor, where there are around four million of them. The most famous are found in the goat-breeding region of Beybazar, the center of the Angora district [44] . In general, Angora goats wear a single-colored, long-haired coat and floppy ears [45] . The coat is generally white, although various colors such as black, gray, yellow and even red can be observed. The Angora breed has flattened, laterally spiral horns. These animals are no taller than 0.65 m, and their long, silky hair is made up of long, straight or curly strands. This hair, called mohair, is used to make carpets and fabrics [44] . Asian Turkey, Australia, America and South Africa all have large herds of Angora goats. As a result, the Angora breed was introduced to Madagascar in several stages from South Africa and Turkey (1890, 1914) [16,44] and Australia (2008). The Angora goat has been introduced to various regions of the French Union, but has been most successful in Madagascar [44] . Initially, a few Angora goats were introduced to indigenous breeders in the Ampanihy district (Atsimo-Andrefana region, Madagascar). This was the start of further cross-breeding with native goats to perfect the breed. The effect of the cross-breeding, which spanned four generations, resulted in a billy-goat capable of transmitting the mohair trait to its offspring. However, other traits, notably uniformity of beige or gray color, pus-white color, lengthening of the hair, extension of the mohair over the entire body and disappearance of the jarre appeared successively in the offspring [44] . Multiple crosses between Angora goats and indigenous Malagasy goats gave rise to the Malagasy Angora goat (figure 9), known to breeders as the Boda goat [32] . The latter, which is the result of crossbreeding, is similar to the pure breeds, apart from a few details. Their size is slightly larger, but they are better adapted to local geoclimatic conditions than pure Angora. Because of their stability, they are referred to as the "Malagasy Angora breed [44] ."

Fig 9:

Madagascar Angora goat (boda goat) [32] The largest population of the Malagasy Angora breed is currently found between the Atsimo-Andrefana (Ampanihy district) and Androy (Beloha district) regions, on both alluvial banks of the Menarandra River (Figure 10). However, a population of pure-bred Angora from the former and the latest introduction in 2008 has been kept on the Ankilimary state farm (Betioky district -Atsimo-Andrefana region -Figure 10). [46] Beloha in 2014 [32] The Angora goat has been known for its hair (mohair wool) as a raw material in the manufacture of mohair carpets between Ampanihy and Beloha (Figure 11).

Fig 11:

Creation of mohair carpets at Ampanihy [47]

Biometrics

In terms of biometric values, the Malagasy Angora goat is higher than the two ecotypes Beroma and Fohivolo (Table 3, p.11), but these values remain within the current purebred standard (Female: HG=65c m and 30-40 Kg; Male: HG=70 cm and 40-60 Kg). Considering the four categories: wild species, traditional population, standardized breed and selected line, according to the evolutionary classification of farm animals proposed by Lauvergne [48] Malagasy Angora populations still belong to the standardized breed category, with primarity indices IPs=0.29 and IPa=0.22 (Table 3, p.11).

Genetic study of the Malagasy Angora breed

Observed and expected heterozygosity rates were calculated for each Angora breed from different countries under the Hardy-Weinberg equilibrium hypothesis [49][50][51] . Table 4 shows the genetic diversity of the Madagascan Angora breed compared with others worldwide. Indeed, the expected and observed heterozygosity for the Malagasy Angora breeds (ANG-MG: He = 0.3478; Ho = 0.3496) was slightly higher than those from South Africa (ANG-ZA: He = 0.3396; Ho = 0.3246) and lower than those recorded from France (ANG-FR: He = 0.3546; Ho = 0.3454) as well as Argentina (ANG-AR: He = 0.3866; Ho = 0.3847) [52] . These differences can be attributed to differences in effective population size, duration of isolation and selection practices in the different production systems. Table 4: Genetic diversity of Madagascan Angora goats compared with others worldwide [52] Breed

Alpine goat morphology

The Alpine goat (Figure 12) is a breed of goat native to the Alps (Switzerland and France). In 1928, a small herd of Alpine goats from France was placed in the Ankaratra at the Vavavato station, where the animals thrive and reproduce [16] . The French Alpine breed features a long, slightly triangular head, a broad, concave forehead, protruding eye sockets and a broad, rounded neck. The ears are long, thin and straight. The back is narrow and protruding, the chest is narrow, high and deep, and the belly is well developed. The udders are short and large. The coat is light buff with glossy highlights. The coat is short and a little coarse [53] .

Fig 12:

French Alpine goat [54] A few pairs of this breed have also been introduced to Madagascar by a cheese producer from the Mid-West in Analavory and from Haute-Matsiatra in Analatsara -Ambohimahasoa (Figure 13).

Boer goat morphology

The Boer goat is a goat breed originally from South Africa. Its butchery qualities have earned it international renown [54] . Indeed, it is considered the best meat goat breed in the world [55] . The Boer goat has a strong head with a Roman nose making a continuous curve from the mouth to the extension of the nose. The horns are well spaced on the head and slightly curved back on the neck. The ears are long, reaching at least to the nose, and hanging down from the head. The neck is muscular and in proportion to the length of the body. The shoulders are broad and rounded (Figure 14). The coat is short, white on the body and red on the head and neck [56,57] . A herd of 1,600 head of this breed was imported from Australia in 2008.

Fig 14:

Boer goat [54] Biometry of Alpine and Boer goats Biometric values of the Alpine goat [58] and the Boer goat [57,[59][60][61] are higher than local breeds (Beroma and Fohivolo ecotypes) and Malagasy Angora (Table 3, p.11 and 5).

Conclusion

Knowledge of the diversity of genetic resources is essential in designing sustainable strategies for their conservation and use. Farm animal diversity originates from wild ancestors and has been successively shaped by mutation processes, genetic drift and human and natural selection. However, only part of the ancestral species diversity has survived in domestic offspring. The present study characterizes the domestic goat breed using morphological and biometric characteristics. Goat breeding has multiple purposes: the production of meat, which is highly prized for its organoleptic quality, and the production of milk used in cheese-making. The production of mohair wool, which is used in the manufacture of carpets and fabrics. Today's domestic goats originate from the domestication of wild goats by immigrant herders during the early and late Neolithic periods in their quest for new territories (Africa, Europe and Asia). Goats do not appear in the primitive faunas of Madagascar, but may have been brought by various tribes: Arab navigators, Antalaotra, Arab and African (Bantu) traders. In fact, thanks to their sturdiness and endurance, they were a mobile fountain of milk and a source of fresh meat for immigrants on their travels. In Madagascar, goats are bred almost everywhere. However, a high percentage of goats (over 80%) is concentrated in the south: the Atsimo-Andrefana, Menabe, Androy and Anosy regions. The Malagasy goat herd is made up of animals from local, mixed-breed and exotic populations. The population of local goat breeds represents the Beroma and Fohivolo ecotypes. The animals are characterized by short and long hair, and their coats are highly variable, with 8/9 existing pigment patterns. The Malagasy Angora population is the result of crossbreeding Angora breeds with local breeds. The population of imported breeds is mainly represented by the Alpine and the Boer. The biometric relationship between weight and height expressed by height at withers and chest circumference proposed by Traoré is used to compare the two local Malagasy ecotypes with African goats. In the present study, the effect of height on weight is assessed, but this study requires further studies with increased sample size to clarify the influence of height on animal weight in Malagasy goats. In other words, the aim is to find out whether this relationship applies to all Malagasy goats, or whether the latter are more specific. In addition, Traoré's method needs to be supplemented by a morpho-biometric study that considers other measurements (body length, thorax depth, etc.) to obtain a more exhaustive mapping of Madagascar's goat genetic resources that will enable the identification of the main ethnic groups. Analysis of molecular data could provide the genetic basis for the appearance of morphological traits such as hair length and coat color, as well as biometric traits in Malagasy goats.

Acknowledgement

AcknowledgmentsThis work was carried out by the FOFIFA-DRZVP team in collaboration with the DRA (MAEP) and jointly funded by FOFIFA-DRZVP, FAO, Goat ADAPTmap Project, AGIN and USDA. The authors thank these organizations.

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