Water buffalo

The water buffalo (''Bubalus bubalis''), also called the domestic water buffalo or Asian water buffalo, is a large bovid originating in the Indian subcontinent and Southeast Asia. Today, it is also found in Europe, Australia, North America, South America and some African countries.
Two extant types of water buffalo are recognized, based on morphological and behavioural criteria: the river buffalo of the Indian subcontinent and further west to the Balkans, Egypt and Italy and the swamp buffalo, found from Assam in the west through Southeast Asia to the Yangtze valley of China in the east.

The wild water buffalo (''Bubalus arnee'') most likely represents the ancestor of the domestic water buffalo. Results of a phylogenetic study indicate that the river-type water buffalo probably originated in western India and was domesticated about 6,300 years ago, whereas the swamp-type originated independently from Mainland Southeast Asia and was domesticated about 3,000 to 7,000 years ago. The river buffalo dispersed west as far as Egypt, the Balkans, and Italy; while swamp buffalo dispersed to the rest of Southeast Asia and up to the Yangtze River valley.

Water buffaloes were traded from the Indus Valley civilisation to Mesopotamia, in modern Iraq, 2500  BC by the Meluhhas. The seal of a scribe employed by an Akkadian king shows the sacrifice of water buffaloes.

At least 130 million water buffaloes exist, and more people depend on them than on any other domestic animal.
They are especially suitable for tilling rice fields, and their milk is richer in fat and protein than that of dairy cattle. A large feral population became established in northern Australia in the late 19th century, and there are smaller feral herds in Papua New Guinea, Tunisia and northeastern Argentina. Feral herds are also present in New Britain, New Ireland, Irian Jaya, Colombia, Guyana, Suriname, Brazil, and Uruguay.

Taxonomy

Carl Linnaeus first described the genus '' Bos'' and the water buffalo under the binomial ''Bos bubalis'' in 1758; the species was known to occur in Asia and was held as a domestic form in Italy. Ellerman and Morrison-Scott treated the wild and domestic forms of the water buffalo as conspecifics, whereas others treated them as different species. The nomenclatorial treatment of the wild and domestic forms has been inconsistent and varies between authors and even within the works of single authors.

In March 2003, the International Commission on Zoological Nomenclature achieved consistency in the naming of the wild and domestic water buffaloes by ruling that the scientific name ''Bubalus arnee'' is valid for the wild form. ''B. bubalis'' continues to be valid for the domestic form and applies also to feral populations.

Characteristics

The skin of the river buffalo is black, but some specimens may have dark, slate-coloured skin. Swamp buffaloes have a grey skin at birth, which becomes slate blue later. Albinoids are present in some populations. River buffaloes have longer faces, smaller girths, and bigger limbs than swamp buffaloes. Their dorsal ridges extend further back and taper off more gradually. Their horns grow downward and backward, then curve upward in a spiral. Swamp buffaloes are heavy-bodied and stockily built; the body is short and the belly large. The forehead is flat, the eyes prominent, the face short, and the muzzle wide. The neck is comparatively long, and the withers and croup are prominent. A dorsal ridge extends backward and ends abruptly just before the end of the chest. Their horns grow outward, and curve in a semicircle, but always remain more or less on the plane of the forehead. The tail is short, reaching only to the hocks. Body the size and shape of horns may vary greatly among breeds. Height at the withers is for bulls, and for cows, but large individuals may attain . Head-lump length at maturity typically ranges from with a long tail. They range in weight from , but weights of over have also been observed.

''Tedong bonga'' is a piebald water buffalo featuring a unique black and white colouration that is favoured by the Toraja of Sulawesi.

The swamp buffalo has 48 chromosomes; the river buffalo has 50 chromosomes. The two types do not readily interbreed, but fertile offspring can occur. Water buffalo-cattle hybrids have not been observed to occur, but the embryos of such hybrids reach maturity in laboratory experiments, albeit at lower rates than non-hybrids.

The rumen of the water buffalo differs from the rumen of other ruminants. It contains a larger population of bacteria, particularly the cellulolytic bacteria, lower protozoa, and higher fungi zoospores. In addition, higher rumen ammonia nitrogen (NH₄-N) and higher pH have been found, compared to those in cattle.

Ecology and behavior

River buffaloes prefer deep water. Swamp buffaloes prefer to wallow in mudholes, which they make with their horns. During wallowing, they acquire a thick coating of mud. Both are well-adapted to a hot and humid climate with temperatures ranging from in the winter to and greater in the summer. Water availability is important in hot climates, since they need wallows, rivers, or splashing water to assist in thermoregulation. Some water buffalo breeds are adapted to saline seaside shores and saline sandy terrain.

Diet

Water buffaloes thrive on many aquatic plants. During floods, they graze submerged, raising their heads above the water and carrying quantities of edible plants. Water buffaloes eat reeds, '' Arundo donax'', a kind of Cyperaceae, '' Eichhornia crassipes'', and Juncaceae. Some of these plants are of great value to local peoples. Others, such as ''E. crassipes'' and ''A. donax'', are a major problem in some tropical valleys and by eating them, the water buffaloes may help control these invasive plants.

Green fodders are used widely for intensive milk production and for fattening. Many fodder crops are conserved as hay, chaffed, or pulped. Fodders include alfalfa, the leaves, stems or trimmings of banana, cassava, Mangelwurzel, esparto, '' Leucaena leucocephala'' and kenaf, maize, oats, '' Pandanus'', peanut, sorghum, soybean, sugarcane, bagasse, and turnips. Citrus pulp and pineapple wastes have been fed safely to buffalo. In Egypt, whole sun-dried dates are fed to milk buffalo up to 25% of the standard feed mixture.

Reproduction

Swamp buffaloes generally become reproductive at an older age than river breeds. Young males in Egypt, India, and Pakistan are first mated around 3.0–3.5 years of age, but in Italy, they may be used as early as 2 years of age. Successful mating behaviour may continue until the animal is 12 years or even older. A good river buffalo male can impregnate 100 females in a year. A strong seasonal influence on mating occurs. Heat stress reduces libido.

Although water buffaloes are polyoestrous, their reproductive efficiency shows wide variation throughout the year. The cows exhibit a distinct seasonal change in displaying oestrus, conception rate, and calving rate.Barile, V. L. (2005). "Reproductive Efficiency in Female Buffaloes". pp. 77–108 in Borghese, A. (ed.
''Buffalo Production and Research''
. REU Technical Series 67. Inter-regional Cooperative Research Network on Buffalo, FAO Regional Office for Europe, Rome. The age at the first oestrus of heifers varies between breeds from 13 to 33 months, but mating at the first oestrus is often infertile and usually deferred until they are 3 years old. Gestation lasts from 281 to 334 days, but most reports give a range between 300 and 320 days. Swamp buffaloes carry their calves for one or two weeks longer than river buffaloes. Finding water buffaloes that continue to work well at the age of 30 is not uncommon, and instances of a working life of 40 years have been recorded.

Domestication and breeding

The most likely ancestor of domesticated water buffaloes is the wild water buffalo ('' Bubalus arnee''), which is native to the Indian subcontinent and Southeast Asia. Two types of domesticated water buffaloes are recognized, based on morphological and behavioural criteria – the river buffalo of the western Indian subcontinent and further west to the Balkans and Italy; and the swamp buffalo, found from Assam in the west through Southeast Asia to the Yangtze valley of China in the east.

River and swamp-type water buffaloes are believed to have been domesticated independently. Results of a phylogenetic study indicate that the river-type water buffalo probably originated in western India and was domesticated about 6,300 years ago, whereas the swamp-type originated independently from Mainland Southeast Asia and was domesticated about 3,000 to 7,000 years ago. The river buffalo dispersed west as far as Egypt, the Balkans, and Italy; while swamp buffalo dispersed to the rest of Southeast Asia and up to the Yangtze River valley.

Swamp-type water buffaloes entered Island Southeast Asia from at least 2,500 years ago, through the northern Philippines where butchered remains of domesticated water buffalos have been recovered from the Neolithic Nagsabaran site (part of the Lal-lo and Gattaran Shell Middens, c. 2200 BCE to 400 CE). These became the ancestors of the distinct swamp-type carabao breed of the Philippines, which in turn spread to Malaysia, Indonesia, and Guam.

The present-day river buffalo is the result of complex domestication processes involving more than one maternal lineage and a significant maternal gene flow from wild populations after the initial domestication events. Twenty-two breeds of the river buffalo are known, including the Murrah, NiliRavi, Surti, Carabao, Anatolian, Mediterranean, and Egyptian buffaloes.Moioli, B. and A. Borghese (2005). ''Buffalo Breeds and Management Systems''. Pages 51–76 in Borghese, A. (ed.
''Buffalo Production and Research''
. REU Technical Series 67. Inter-regional Cooperative Research Network on Buffalo, FAO Regional Office for Europe, Rome. China has a huge variety of water buffalo genetic resources, with 16 local swamp buffalo breeds in various regions.

Genetic studies

Results of mitochondrial DNA analyses indicate that the two types were domesticated independently. Sequencing of cytochrome b genes of ''Bubalus'' species implies that the water buffalo originated from at least two populations, and that the river-type and the swamp-type have differentiated at the full species level. The genetic distance between the two types is so large that a divergence time of about 1.7 million years has been suggested. The swamp-type was noticed to have the closest relationship with the tamaraw of the northern Philippines.

A 2008 DNA analysis of Neolithic water buffalo remains in northern China (previously used as evidence of a Chinese domestication origin) found that the remains were of the extinct '' Bubalus mephistopheles'' and are not genetically related to modern domesticated water buffaloes. Another study in 2004 also concluded that the remains were from wild specimens. Both indicate that water buffaloes were first domesticated outside of China. Analyses of mitochondrial DNA and single-nucleotide polymorphism indicate that swamp and river buffaloes were crossbred in China.

An analysis of the genomes of 91 swamp and 30 river buffaloes showed that they separated already before domestication about .

Distribution of populations

By 2011, the global water buffalo population was about 172 million.Borghese, A. (2011)
"Situation and Perspectives of Buffalo in the World, Europe and Macedonia"
''Macedonian Journal of Animal Science'' 1 (#2): 281–296. The estimated global population of water buffalo is 208,098,759 head distributed in 77 countries in five continents.

In Asia

More than 95.8% of the world population of water buffaloes are kept in Asia, including both the river-type and the swamp-type.Borghese, A., Mazzi, M. (2005). ''Buffalo Population and Strategies in the World''. Pages 1–39 in Borghese, A. (ed.) ''Buffalo Production and Research''. REU Technical Series 67. Inter-regional Cooperative Research Network on Buffalo, FAO Regional Office for Europe, Rome. The water buffalo population in India numbered over 97.9 million head in 2003, representing 56.5% of the world population. They are primarily of the river type, with 10 well-defined breeds: the Bhadawari, Banni, Jafarabadi, Marathwadi, Mehsana, Murrah, Nagpuri, Nili-Ravi, Pandharpuri, Surti, and Toda buffaloes. Swamp buffaloes occur only in small areas in northeastern India and are not distinguished into breeds.C. V. Singh, R. S. Barwal (2010). Buffalo Breeding Research and Improvement Strategies in India. In
''The Buffalo in the World''
Proceedings of the 9th World Buffalo Congress, Buenos Aires, April 2010, pages 1024–1031. Archived 17 April 2012.

In 2003, the second-largest population lived in China, with 22.76 million head, all of the swamp-type, with many breeds kept only in the lowlands, and other breeds kept only in the mountains; as of 2003, 3.2 million swamp-type carabao buffaloes were in the Philippines, nearly 3 million swamp buffaloes were in Vietnam, and roughly 773,000 buffaloes were in Bangladesh. About 750,000 head were estimated in Sri Lanka in 1997. In Japan, the water buffalo was used as a domestic animal throughout the Ryukyu Islands or Okinawa prefecture, however it is almost extinct now and mainly used as a tourist attraction. Per a 2015 report, about 836,500 water buffaloes were in Nepal