Reproduction in Wild Buffaloes

Feral buffaloes inhabit many parts of the world. Their numbers are significantly low for some types to be listed as endangered species, whereas some other types are existent in large numbers but continue to live in their natural habitat. The African buffalo Syncerus caffer is present in significant numbers in the African continent. Others inhabit parts of Asia, Philippines and Indonesia. The wild water buffalo Bubalus arnee is highly endangered with remaining populations at risk of hybridization with domestic buffalo. There are very few studies on reproductive processes in the feral species of buffalo owing to their presence in natural habitat, seasonal social ecology and exceptionally large size. Information on the reproductive processes has evolved by observation in captivity in national parks that were developed in many regions and follow up in their natural habitat.

Classed as the largest bovids, and being the latest and most advanced evolving ruminants, bovines originated in the lower Pliocene in Asia [1]. All bovines are water dependant and roughage feeders, mostly inhabiting woodland and forests. Recent molecular and morphological studies indicated a sub-familial separation between cattle (Bos and Bison) and buffalo (Syncerus and Bubalus) [2-5], ribosomal-DNA data closely links Syncerus and Bubalus [6].

As early as the 1800s, the importance of long-term sustainable reproductive success was acknowledged by natural scientists [7]. The second strongest impulse of nature is the continuation of a species [8], therefore successful production of young is the determining factor for the success and viability of a population [9].

The reproductive reaction of members of a population can be influenced by intrinsic and extrinsic factors. Intrinsic factors, also known as self-regulation, are where social behaviour or genetic polymorphism plays a role in fertility or mortality [10]. Density independent, or extrinsic control, is where occasional regulation takes place disguised by independent environmental factors [10]. Extrinsic factors include famine, disease, hunting [9], stress and habitat changes [11], natural catastrophes [9,11], and most importantly food quality and quantity [12]. All the above factors have a negative feedback mechanism that ultimately controls population size [10]. Cellular maintenance, thermoregulation and locomotor costs have to be satisfied first from food ingested, the energy that remains will be used for individual growth, and the remainder will be used for reproduction [11,13].

Most bovines are gregarious and non-territorial with male dominance based on size, increasing with age. During the breeding season mixed herds are formed, however, sexes will range separately during other seasons. Syncerus caffer is the exception to the rule forming mixed herds even during non-breeding seasons [14,15]. Most Bovini have a 9 to 11 month gestation period, with females reaching sexual maturity at around 4 years of age and males at 7 years of age [1]. In this chapter, the reproductive parameters of feral buffaloes are mentioned.

1. African Buffalo

Syncerus is an African endemic genus also sometimes referred as Cape buffalo, originating from either the Ethiopian highlands or the great plains of East Africa during the late Pleistocene. Since 1779, ninety two (92) zoological names have been given to the African buffalo with as many as 43 subspecies [16,17]. Showing the greatest range of morphological variation of all herbivore species in Africa, the buffalo can be divided into two definite subspecies [18,19], ranging from the lightly built, reddish, small-horned forest buffalo Syncerus caffer nanus to the heavily built, darker, big-horned savanna buffalo Syncerus caffer caffer [16-19] (Fig. 1). Where ranges of these subspecies overlap, hybrids are found causing much debate amongst taxonomists; however, they are either classed as Syncerus caffer aequinoctialis [16,17,20] or Syncerus caffer brachyceros [16,19-21].

Figure 1. African Savana Buffaloes Syncerus caffer caffer (M. Cromhout).

1.1. African Savanna Buffalo (Syncerus caffer caffer)

Savanna buffaloes are believed to be highly productive to such a degree, that culling is necessary in protected areas to avoid habitat degradation due to overpopulation [1]. Savanna buffalo population sizes could stabilize in size in 9 years after establishment, but only in a favourable habitat [22]. With a clearly defined wet and dry season, Savanna buffaloes will show seasonal breeding patterns [14].

1.1.1. Morphologic and Age Wise Grouping

It is impossible for a human observer to accurately estimate an adult buffalo bull's age based on horn morphology or size alone [19]. Although it is impossible to age animals accurately in the field unless the date of birth is known, broad age classes can be determined. For the purpose of this chapter, age class determination was done in the field based on horn shape and development, body measurements, and changes in the colour and texture of the coat. The age classes identified [1,4,10,47,62] were as follows:

Infants - Juveniles - Sub adults and Adults

Buffaloes older than 48 months were classed as adults. The coat colour changes to a black. The tips of the horns of females begin the backward sweep and are wide, dipping lower than those of sub-adult females (Fig. 2). The crown of the head shows signs of abrasion and hair loss, and old females have shrunken and bony faces that are associated with a deteriorating physical condition. The boss of adult males is a complete shield when the two horn bases have met in the centre of the skull, usually after 7 years of age (Fig. 3). Bulls older than 11 years are classed as old and are seldom seen in a herd. These animals are massive, with numerous scars on their bodies. The areas above the eyes and on the cheeks are usually speckled with patches of grey-white hair. Areas on the neck, belly and hindquarters become hairless. Dewlap and testicle size can also be used in ageing old males and could even be an indication of social dominance.

Figure 2. African Savana Buffalo cow (M. Cromhout).

Figure 3. African Savana Buffalo bull (M. Cromhout).

1.1.2. Puberty

Puberty starts when a heifer starts to ovulate whereas sexual maturity is reached when a female reaches her optimum reproductive potential. The age of sexual maturity is correlated to body weight, and there is a large variation in the age at first calving in the literature [23]. Fecundity among cows could be 86% under optimal conditions. Studies on herbivores have confirmed that puberty is only reached once a certain body mass, rather than an age is reached [24,25]. Puberty in an herbivore is therefore influenced by the availability and quality of the food, especially protein intake [9,12]. Nutritional conditions in the first 2 years of life could therefore have an effect on the fertility of an animal, with fertility being delayed under conditions of nutrient stress [10]. Therefore, rainfall which influences the nutritional state of the forage would be the primary factor affecting herbivore ovulation and conception rates [12,13,26].

Females will start ovulation at around 3.2 years of age (body mass of 325-374 kg) but will have their first calf at an age of 5 years whilst bulls will only enter the reproductive competition at the age of 7 or 8 years [1,4,14,26]. Spermatogenesis commences in males at around 2.5 years of age with a testis mass of 130 g and a body mass of 300 kg [26]. In a study undertaken in Zimbabwe in the Matusadona National Park, the diameter of the seminiferous tubules and the testes mass increased from August and peaked just before and during conception; at no stage did spermatogenesis cease [26]. It has been suggested that endocrine function and seminal quality differ seasonally; bulls may also experience selective gonadal suppression related to social status [27]. Bulls older than 11 years leave the herd due to a decline in androgen production and thus decreased libido which is caused by a testicular interstitial tissue increase and thus a loss in interstitial cell function [12].

1.1.3. Estrus Behaviour and Mating

Both mating and calving will be limited to the wet season. Bulls will test female reproductive status by prompting the cow to urinate by licking the vulva and then smelling the urine, also referred to as flehmen [14] (Fig. 4). Once a cow is in heat, she will be closely guarded by a bull but a series of displacements by other bulls of higher rank will follow. After 2 or 3 days in proestrus, a cow will be in full estrus during which the dominant bull will mount her [1]. The oestrous cycle is 18.4 days long (18 to 22 days) with an inter-estrus period of 12-13 days [28]. On average, 2 copulations in 30 minutes lasting 10 seconds each were observed in wild Savanna buffaloes [16].

Figure 4. An African Savana buffalo bull showing flehmen (M. Cromhout).

1.1.4. Reproductive Social Ecology

Savanna buffaloes demonstrate a re-entrant consecutive polygyny where adult bulls move in and out of mixed breeding herds depending on breeding opportunities, body condition and dominance hierarchies between bulls [10,14,19]. Optimal conception rates result from optimal feeding conditions for pregnant cows between parturition and oestrus; this is because of a higher food requirement during late pregnancy and lactation [29]. This higher food requirement during the last two months of pregnancy is accentuated because rumen fill decreases to compensate for space for the growing foetus [12]. Parturition must preferably take place when the cow is in a peak condition in the wet season, and for optimal productivity the calf must be weaned at 9 months of age. Females have two pairs of inguinal mammae [4,10]. To obtain a weaning age of 9 months for optimal population growth, the habitat must be in a condition to sustain a young growing calf. If the habitat is in a poor condition or has a low nutrient quality, the calf will want to suckle longer than usual due to a lack in adequate nutrient intake from the available graze, therefore extending the inter-calving period and resulting in a limited and reduced productivity for the cow and the population as a whole [10,16,19].

1.1.5. Nutritional Requirements for Reproduction

The dietary requirements of an animal are central to animal ecology [10,30] and the management of any species depends on a thorough knowledge of its nutritional requirements [31-33]. Animals are dependent upon energy and nutrients obtained from ingested food [19,34], and their survival and fertility are directly affected by nutrition [35-38]. Faecal nitrogen is positively correlated with dietary protein, dry matter intake and digestibility, and mass changes in mature animals [37,39]. A faecal nitrogen concentration of less than 14 g N/kg DM (dry matter) indicates a nitrogen deficiency in grazers [37]. Grant et al. [40], found a significant relationship between physical condition and faecal nitrogen for buffaloes. Physical condition will decrease if faecal nitrogen falls below 11.5 g/kg DM. The minimum nitrogen concentration that is necessary in grass to maintain rumen fermentation is between 11.0 and 12.0 g N/kg DM [39,40]. During the drought of 1992-1993 in the Kruger National Park, the mean faecal nitrogen concentration of buffalo was 11.5 g/kg DM, some of the animals were in a poor physical condition, and the population declined in numbers with calving percentages as low as 4.2% [39]. Faecal nutrient levels have been used to predict dietary levels in elk [41], white tailed deer [42], cattle [43], duiker, eland, blue wildebeest, impala, zebra [37] and sable antelope [44]. Faecal nitrogen and phosphorus can be used as indicators of the nutritional status and ecology of animals [7,45] and the nutritive content of the veld (certain wide open rural spaces bearing grass, bushes, or shrubs, or thinly forested, characteristic of parts of southern Africa) [37,40]. It is important to consider faecal phosphorus and nitrogen concentrations together because their excretion is linked. When faecal phosphorus concentrations are below 2.0 g/kg organic matter (OM), faecal nitrogen concentrations will increase and cause a decrease in faecal phosphorus [39].

1.1.6. Inter-calving Intervals

The mean pregnancy rate of African buffalo cows is 75%. From this, the inter-calving period can be defined as the gestation period divided by the pregnancy rate (343 days/0.75) thus 457 days. An inter-calving period will range between 15 months and 2 years depending on nutritional conditions. Calf survival is high for the first two years due to predation, disease and rainfall which causes adverse seasonal effects on the habitat [47]. Cows that lose calf postpartum could come into oestrus within five weeks. The variation in the calving interval is due to post-partum anoestrus. Ideally, calves are weaned at 5 months of age [25], but suckling can be tolerated for as long as 9 months [10]. Lactation in buffalo can last up to the 7th month of the next pregnancy [12]. This extended lactation period and a low quality diet in the dry season could result in undernutrition of the foetus, resulting in underweight calves with impaired survival. In the Serengeti, such underweight calves were known to be abandoned and they eventually died [29]. Undernourished calves lose mass soon after birth and it could take up to 1 month to recover their original birth mass [12]. A post-partum anoestrus was observed in Botswana [48] and in South Africa and a lactational anestrus without follicular growth or sexual activity was also observed [47].

1.1.7. Postpartum Oestrus

Due to lactation anoestrus, if a calf is allowed to suckle for several months, oestrus will occur after three to five months postpartum [23].

1.1.8. Gestation and Parturition

The gestation period is 11.5 months (Table 1). Calving usually takes place early in the morning or late afternoon when the herd is resting and is usually completed within 2 hours. Yearlings will be rejected once a new calf is born [1]. Birth weight averages between 35 and 50 kg. Calves can stand within 10 minutes but they are poorly coordinated and slow runners for several weeks. Calves and mothers are often left alone whilst the herd goes feeding and drinking during which time the mother will lead the calf into the nearest cover and slowly lead it back to the herd. Unlike cattle, buffalo calves nurse between the mothers hind legs for up to 10 minutes at a time [1,10]. Dystocia doesn't normally occur under natural conditions due to natural selection. Buffalo milk contains 6% protein, 5% carbohydrates and 8% fat [23]. With a gestation period of approximately 340 days, parturition occurs to take advantage of the period when forage has its highest protein content.

1.1.9. Sex Ratio

The infant and juvenile buffaloes of Tswalu Kalahari Reserve observed in 2004 had a sex ratio of 0.5 and 2 males per female respectively. The data as presented here revealed the possibility of an interesting phenomenon known as the Trivers and Willard hypothesis [14]. According to this hypothesis, paternal condition could be central in influencing the sex ratio of the offspring, with more male offsprings being produced when females are in a good physical condition [49]. Resource availability often relates to variations that are found in sex ratios at birth [50,51]. Due to the pronounced sexual dimorphism of size in buffalo, optimum production will favour the production of male offspring as opposed to female offspring [52,53]. This happens because a bull can produce a potentially higher number of offspring than a cow in a lifetime [54]. In comparison, male elephant calves have a greater nutritional demand than female ones [55]. This could play a significant role in times of food stress, when producing female calves will be the better option, as was found in red deer (Cervus elaphus) [51]. Female feral horses (Equus caballus) that were in a good physical condition favoured male foals [56]. Roe deer (Capreolus capreolus) adjusted their foetal sex ratio according to their physical condition [57], moreover as was confirmed for various ungulate species [58]. The possibility of such a hypothesis was also formulated in the Sabi Sand Game Reserve where more female calves were produced during the drought years in the 1980's [54]. Male suckling buffalo calves were heavier than female ones resulting in a higher maternal cost for males [47], the production of male foetuses decline with increasing age of the mother [59]. Long-term studies are needed in order to determine conclusively whether the buffalo, or any other wildlife species, can modify its sex ratio at conception according to the rainfall received [60]. Although different sex ratio trends have been reported in the same species [50,52], specific physiologically-based studies of more species are required to test if females can adjust their foetal sex ratios relative to their physical condition [52].

1.1.10. Population Dynamics

A balanced age structure must be maintained in any animal population for optimal productivity, because deviation from such an age structure could affect the population growth rate. Yet, the ratio of the age classes in a population can be an indication of its current and expected reproductive state [61]. It is recommended that 30 to 40% of a large herbivore population must consist of young, reproductive animals [9]. In a buffalo population, a ratio of five to 15 sexually mature females per sexually active male is recommended for maximum productivity [9]. However, most recorded natural populations have a 1:1 sex ratio [10,47]. Sexing of immature animals in the field is difficult, and animals less than 24 months of age can only be sexed correctly on visualization of their external genitalia [19]. Adult males have a heavy horn shield, known as a boss, that covers the top of the head above the eyes. Females have horns that are narrower than males, and the head seems flat in profile due to the absence of the forehead ridge [10,21]. There are various methods to age mammals, including the following: A change in body size [47,62,63] and body mass [47,64], an increase in the eye lens mass which indicates increased age [64], degradation of teeth [12,64] and changes in incremental growth lines in bone [64], changes in bone marrow with red bone marrow being replaced by fat in older animals [64], fusion of the epiphyses [64], changes in external features [12] and horn or claw development [10,46,47].

Recently the African buffalo has come under threat due to various diseases, from this intensive breeding of "disease-free" buffalo started. In the wild African buffalo populations are kept in equilibrium with their environment with factors such as food, disease and predation. Foot-and-mouth disease, tuberculosis, brucellosis, corridor disease and parafilariosis are important diseases in the African buffalo.

1.2. African Forest Buffalo Syncerus caffer nannus

Data on the much smaller Forest buffalo are very scant.

Figure 5. African Forrest Buffalo Syncerus caffer nanus (Wildlife Conservation Society Congo).

1.2.1 Morphologic and Age Wise Grouping

They are much smaller (250 to 320 kg), the coat colour is reddish and the horns do not fuse at the base like in the Savanna buffalo [15,65,66].

Forest buffalo bulls form harems of cows, juveniles and calves and stay with the herd for life. Cows do move between herds, this is the exception to the rule [15,65,66]. The gestation period also seems to be 11 months [15,65,66] (Table 1).

2. Wild Water Buffalo (Bubalus arnee)

The wild water buffalo, also known as Asiatic or Asian buffalo, Bubalus arnee is the ancestor to the domesticated water buffalo Bubalus bubalis and the second largest wild bovid, slightly smaller than the gaur (Bos gaurus). The wild water buffalo is highly endangered, with the few remaining populations already affected or likely to be increasingly affected by hybridization with domestic buffalo [68]. The wild water buffalo is currently endangered with an estimated number of less than 4000 [69]. Bubalus arnee is included in CITES Appendix III (www.cites.org/eng/app/index.php), and is legally protected in Bhutan, India, Nepal, and Thailand. The International Commission on Zoological Nomenclature (2003) ruled that the name for this wild species is not invalid by virtue of its being antedated by a name based on a domestic form. Therefore, IUCN considers the wild forms of Water Buffalo under Bubalus arnee, while the domestic forms are considered under B. Bubalis [70]. Despite this, B. arnee was listed as a subspecies of B. bubalis [71]. Three subspecies were recognized, all still apparently existing [72]: B. a. arnee (much of India and Nepal); B. a. fulvus (Assam and neighbouring areas); and B. a. theerapati (Southeast Asia) [69].

In 2003, the International Commission on Zoological Nomenclature placed Bubalus arnee on the Official List of Specific Names in Zoology, recognizing the validity of this name for a wild species. Most authors have adopted the binomen Bubalus arnee for the wild water buffalo as valid for the taxon.

Only few DNA sequences are available from wild water buffalo populations. Wild populations are considered to be the progenitor of modern domesticated water buffaloes, but the genetic variation within B. arnee is unclear, and also how they are related to the domesticated river and swamp forms.

Figure 6. Asian Water Buffalo (Bubalus arnee) (Photo taken in UduWalawe NP, Sri Lanka. Credit: Steve Garvie/Wikipedia (CC BY-SA 2.0).

3. Domestic Water Buffalo Bubalus bubalis

Originating from selective breeding of Bubalus arnee, the domestic Asian water buffalo are used as livestock in various countries but are also regarded as feral in other. Without reasonable nutrition, the animals cannot reach puberty as early in life as genetic capability would normally allow. A detailed study of ovulation and cycle length on Brazilian water buffaloes was conducted and the median cycle length was ~23 days; ovulation occurred usually at night [77]. Females normally produce calves every other year after gestation of 9 to 11 months. Calves are weaned at 6 months. Young bulls typically remain with maternal herds, which consist of around 30 buffaloes, for three years after birth. They then go on to form small, all-male herds [78]. Water buffaloes in the Northern Territory of Australia have a well defined breeding season in the wet or very early dry season. The birth of a calf is of major importance for the clan and for the family group of which that clan is a part. A number of calves are left in the care of an adult while their mothers go to graze. The female calf remains with its mother for many years, possibly for life, but at 2-3 y old the male calf is driven from the group by an adult bull when a cow in the group comes into oestrus. Most buffalo cows will readily adopt an orphan calf and within 8 days it is impossible to distinguish between the orphan and the group calves [79].

A population of Bubalus bubalis L. was studied for two years in Rahuna National Park (RNP) in Sri Lanka by seasonal direct counting. The main breeding season was between March and May. Calves were born from end of December to about mid-May, thus from the end of the main rainy season to the beginning of the dry season when the grasses show a luxuriant growth. Although the observed male to female ratio up to the sub-adult stage is 1:1, that of the adults fluctuated between 1:4.7 and 1:1.9 favouring females, males being relatively more frequent during the breeding season. Since there appears to be no selective mortality of adult males, the observed deviation from 1:1 sex ratio could probably be due to adult males moving away from the study area into deeper forest [80].

3.1. Morphologic and Age Wise Grouping

Wild water buffaloes are larger and heavier than domestic buffaloes, and weigh from 700 to 1,200 kg. Their head-to-body-length is 240 to 300 cm with a tail 60 to 100 cm long, and a shoulder height of 150 to 190 cm. Both sexes carry horns that are heavy at the base and widely spreading up to 2 m along the outer edges, exceeding in size the horns of any other living bovid. Their skin colour is ash grey to black. The moderately long, coarse and sparse hair is directed forward from the haunches to the long and narrow head. There is a tuft of hair on the forehead, and the ears are comparatively small. The tip of the tail is bushy; the hooves are large and splayed.

Figure 7. Domestic Water Buffalo (Bubalus bubalis) grazing at the side of the road, by Lake Phayao. (Credit: Heiko S.).

3.2. Puberty

Sexual maturity is reached at three years of age for females and 18 months for males.

3.3. Oestrus Behaviour and Mating

Dominant males mate with the females of a clan who subsequently drive them off. Clans are led by old cows, even when bulls accompany the group. Adult males form bachelor groups of up to 10 individuals, with older males often solitary, and spend the dry season apart from the female clans, very much like the Savanna buffalo. They are seasonal breeders in most of their range, and breed typically in October and November. However, some populations breed year round [73].

An inter-calving interval of one year was observed [73]. A single calf is born after a gestation period of 10 to 11 months, however, twins are possible.

3.4. Reproductive Social Ecology

Wild water buffaloes are both diurnal and nocturnal. Adult females and their young form stable clans of as many as 30 individuals that have home ranges of 170 to 1,000 ha, including areas for resting, grazing, wallowing and drinking. Clans are led by old cows, even when bulls accompany the group. Several clans form a herd of 30 to 500 animals that gather at resting areas. Adult males form bachelor groups of up to 10 individuals, with older males often solitary, and spend the dry season apart from the female clans.

4. Mindoro Dwarf Buffalo or Tamaraw (Bubalus mindorensis)

Found on the Island of Mindoro, this critically endangered bovine [74] is known to be a largely solitary but fierce animal [75]. Tamaraws will breed early in the dry season (December to May). After a gestation period of 276 to 315 days (Table 1), a single calf is born in the wet season (June to November) [75,76]. Males and females occasionally associate temporarily throughout the year [76]. There is an inter birth interval of two years, although one female has been sighted with three juveniles [76].

Figure 8. Mindoro dwarf buffalo or Tamaraw (Bubalus mindorensis). A tamaraw bull (Bubalus mindorensis) crossing a grassy field. Adult bulls are locally called toro and are rightly respected for their size and surprising agility. Taken by Gregg Yan in 2012 at the Mount Iglit-Baco National Park in Occidental Mindoro Province, Philippines. (Credit: Gregg Yan).

5. Lowland Anoa (Bubalus depressicornis) and Mountain Anoa (Bubalus quarlesi)

Found in Indonesia, both species are endangered, there are still arguments on whether they are two distinct species [81-83] although the common names relate to a still uncertain altitudinal separation [2].

5.1 Morphologic and Age Wise Grouping

The large form (Lowland Anoa) inhabits low-lying areas and the smaller form (Mountain Anoa) live at higher elevations [81]. The mountain Anoa standing only 70 cm tall, is the smallest of all wild cattle. Both species are solitary browsers, feeding on grasses, woody twigs and leaves from trees and shrubs. The typical lifespan in captivity is reported to be 20 to 30 years.

Figure 9. Lowland Anoa (Bubalus depressicornis) photographed May 2011 in Marwell Zoo, Hampshire, UK. (Credit: The Land).

5.2. Puberty

Sexual maturity is attained at 2 to 3 years of age (in captivity), typically producing one offspring per year, although in wild conditions, this may be less [82,83].

5.3. Parturition and Intercalving Intervals

Due to their decreasing numbers and unsuccessful breeding in captivity (mostly due to their aggressiveness, solarity, wildness and monogamy), assisted reproductive techniques were examined [86].

In a study done on Anoa in Java, semen was collected and oestrus-synchronized females were inseminated by intracervical insemination. Through observation, it was concluded that the gestation period was 313 days (inseminated) and 324 days (natural mating). The parturition behaviour and the process were also mentioned in this study. The first, second and third stages of parturition were completed in pregnant Anoa's in 6-8 h, 30 min-1 h and 15 min-3 h respectively [86].

6. Reproductive Diseases in Feral Buffaloes

Very few descriptions of various reproductive problems in feral buffaloes are available, however, these problems appears to be few due to natural selection. Reproductive diseases like brucellosis [87,88] and leptospirosis have been sporadically described. The importance of these diseases in wild buffalo lies in the potential threat of spread to domestic cattle and other ruminants. In addition, B. abortus is a human pathogen. In humans, brucellosis can be a serious, debilitating and sometimes chronic disease that may affect a variety of organs.

In South Africa, several species of wildlife (African buffalo, hippopotamus [Hippopotamus amphibius], zebra [Equus burchellii], eland, waterbuck and impala [Aepyceros melampus]) have tested serologically positive for brucellosis, but these species are probably of minor importance in the epidemiology of bovine brucellosis in southern Africa. This is possibly due to the relatively infrequent contact between cattle and wildlife [84]. As with bison, few records exist of abortions due to brucellosis in wildlife in southern Africa, although B. Abortus biovar 1 has been isolated from the cotyledons of pregnant buffaloes at slaughter [87], and experimental infection of pregnant buffaloes resulted in late term abortions. Although serological surveys have revealed up to 23% positive reactors in buffaloes from the Kruger National Park [88], the authorities in South Africa believe that these animals probably do not currently constitute a significant source of infection for cattle because of the strict control measures to prevent the spread of foot and mouth disease across the boundaries of the Park and from adjoining private nature reserves, which limit contact between buffalo and cattle. In Zimbabwe, in the early 1990s, 14 of 29 (48%) serum samples from buffaloes were diagnosed as positive. These samples were collected from game areas where contact with domestic cattle, sheep and goats could not be excluded. It was concluded that brucellosis might be a sustainable infection in African buffalo populations, which consequently should be considered a possible source of re-infection for domestic stock [89]. In a study on African buffalo in Uganda, 2% animals were recorded to be seropositive to Brucella.

Sporadic abortion due to these two diseases is possible in the feral buffaloes and few reports record fetal mummification due to other diseases.

7. Assisted Reproductive Technologies in Feral Buffaloes

Advances in the use of reproductive technologies in the feral buffaloes have been slow owing to their presence in the natural habitat, larger size, poorly defined purposes and difficulties in handling. The first two Anoa were born (April 2010) by artificial insemination of female Anoa in captivity with semen collected by electro-ejaculation from anesthetized male Anoa. Similar reports on African buffaloes are not traceable. The semen characteristics of Anoa mention a white transparent colour, low volume (1.02±0.28 mL), slightly acidic pH (6.93±0.19), nil mass activity, progressive motility of 52.5±18.91%, sperm concentration of 263.33±105.06 x 106 sperms/mL, and 67.48±8.24% of live sperms.

Semen from African buffalo is usually collected from epididymides of dead/killed animals [90-96]; although it has also been collected from anesthetized bulls by electro-ejaculation [99]. These studies have been carried out primarily because African buffalo translocation has been restricted since it is considered a reservoir for many diseases [100] and thus cryopreservation of sperm was considered important [92-94,96]. Another purpose of cryopreservation of epididymal sperm from African buffalo could be its use for in vitro fertilization [91,101]. Spermatozoa from epididymides are collected by dissection and flushing through the vas deferens using a syringe [98]. Spermatozoa are diluted in extender and equilibrated with 5% glycerol [97] for 2-9 h [98], filled in empty straws and cryopreserved. Commercially available Triladyl (Minitub, Germany) has been considered better for freezing of African buffalo epididymal sperms [98].

Anoa semen collected by electro-ejaculation was diluted with Tris egg yolk extender before being used for insemination [84] at a dose rate of 100 x 106 sperms/1.0 mL. Anesthetized oestrus-synchronized female Anoas are inseminated transcervically [84], yet pregnancy rates were only 25% in this study. One study observed seasonal effects (increase during the breeding season) in the ejaculate volume, sperm motility and proportion of morphologically normal spermatozoa from African buffalo males and some, but not all, adult bulls produced high circulating concentrations of testosterone associated with increased testicular LH receptor binding during the breeding season[99].

Little efforts have been made towards in vivo and in vitro production of embryos from African buffalo oocytes [101] or production of cattle x buffalo hybrid embryos using cattle oocytes and African buffalo epididymal sperm [102] or somatic cell nucleus transfer [103]. Such studies are yet to progress to result in pregnancies and live births.