Book Cows

[Pavido Scalf]

Cattle are commonly raised for meat, for dairy products, and for leather. As draft animals, they pull carts and farm implements. In India, cattle are sacred animals within Hinduism, and may not be killed. Small breeds such as the miniature Zebu are kept as pets.

Taurine cattle are widely distributed across Europe and temperate areas of Asia, the Americas, and Australia. Zebus are found mainly in India and tropical areas of Asia, America, and Australia. Sanga cattle are found primarily in sub-Saharan Africa. These types, sometimes classified as separate species or subspecies, are further divided into over 1,000 recognized breeds.

Around 10,500 years ago, taurine cattle were domesticated from wild aurochs progenitors in central Anatolia, the Levant and Western Iran. A separate domestication event occurred in the Indian subcontinent, which gave rise to zebu. There were over 940 million cattle in the world by 2022. Cattle are responsible for around 7% of global greenhouse gas emissions. They were one of the first domesticated animals to have a fully-mapped genome.

Cattle have one large stomach with four compartments; the rumen, reticulum, omasum, and abomasum. The rumen is the largest compartment and it harbours the most important parts of the microbiome.[11] The reticulum, the smallest compartment, is known as the "honeycomb". The omasum's main function is to absorb water and nutrients from the digestible feed. The abomasum has a similar function to the human stomach.[13]

Cattle regurgitate and re-chew their food in the process of chewing the cud, like most ruminants. While feeding, cows swallow their food without chewing; it goes into the rumen for storage. Later, the food is regurgitated to the mouth, a mouthful at a time, where the cud is chewed by the molars, grinding down the coarse vegetation to small particles. The cud is then swallowed again and further digested by the micro-organisms in the cow's stomach.[13]

The gestation period for a cow is about nine months long. The ratio of male to female offspring at birth is approximately 52:48.[14] A cow's udder has two pairs of mammary glands or teats.[15] Farms often use artificial insemination, the artificial deposition of semen in the female's genital tract; this allows farmers to choose from a wide range of bulls to breed their cattle. Estrus too may be artificially induced to facilitate the process.[16] Copulation lasts several seconds and consists of a single pelvic thrust.[17]

Cows seek secluded areas for calving.[18] Semi-wild Highland cattle heifers first give birth at 2 or 3 years of age, and the timing of birth is synchronized with increases in natural food quality. Average calving interval is 391 days, and calving mortality within the first year of life is 5%.[19] Beef calves suckle an average of 5 times per day, spending some 46 minutes suckling. There is a diurnal rhythm in suckling, peaking at roughly 6am, 11:30am, and 7pm.[20] Under natural conditions, calves stay with their mother until weaning at 8 to 11 months. Heifer and bull calves are equally attached to their mothers in the first few months of life.[21]

Cattle have a variety of cognitive abilities. They can memorize the locations of multiple food sources,[23] and can retain memories for at least 48 days.[24] Young cattle learn more quickly than adults,[25] and calves are capable of discrimination learning,[26] distinguishing familiar and unfamiliar animals,[27] and between humans, using faces and other cues.[28] Calves prefer their own mother's vocalizations to those of an unfamiliar cow.[29] Vocalizations provide information on the age, sex, dominance status and reproductive status of the caller, and may indicate estrus in cows and competitive display in bulls.[30] Cows can categorize images as familiar and unfamiliar individuals.[27] Cloned calves from the same donor form subgroups, suggesting that kin discrimination may be a basis of grouping behaviour.[31] Cattle use visual/brain lateralisation when scanning novel and familiar stimuli.[32] They prefer to view novel stimuli with the left eye (using the right brain hemisphere), but the right eye for familiar stimuli.[33] Individual cattle have also been observed to display different personality traits, such as fearfulness and sociability.[22]

Vision is the dominant sense; cattle obtain almost half of their information visually.[34] Being prey animals, cattle evolved to look out for predators almost all round, with eyes that are on the sides of their head rather than the front. This gives them a field of view of 330, but limits binocular vision (and therefore stereopsis) to some 30 to 50, compared to 140 in humans.[27] They are dichromatic, like most mammals.[35]Cattle avoid bitter-tasting foods, selecting sweet foods for energy. Their sensitivity to sour-tasting foods helps them to maintain optimal ruminal pH.[34] They seek out salty foods by taste and smell to maintain their electrolyte balance.[36] Their hearing is better than that of horses[37] but worse at localising sounds than goats, and much worse than dogs or humans.[38] They can distinguish between live and recorded human speech.[39] Olfaction probably plays a large role in their social life, indicating social and reproductive status.[34][40] Cattle can tell when other animals are stressed by smelling the alarm chemicals in their urine.[41] Cattle can be trained to recognise conspecific individuals using olfaction only.[40]

Cattle live in a dominance hierarchy. This is maintained in several ways. Cattle often engage in mock fights where they test each other's strength in a non-aggressive way. Licking is primarily performed by subordinates and received by dominant animals. Mounting is a playful behavior shown by calves of both sexes and by bulls and sometimes by cows in estrus,[42] however, this is not a dominance related behavior as has been found in other species.[19] Dominance-associated aggressiveness does not correlate with rank position, but is closely related to rank distance between individuals.[19] The horns of cattle are honest signals used in mate selection. Horned cattle attempt to keep greater distances between themselves and have fewer physical interactions than hornless cattle, resulting in more stable social relationships.[43] In calves, agonistic behavior becomes less frequent as space allowance increases, but not as group size changes, whereas in adults, the number of agonistic encounters increases with group size.[44]

Dominance relationships in semi-wild highland cattle are very firm, with few overt aggressive conflicts: most disputes are settled by agonistic (non-aggressive, competitive) behaviors with no physical contact between opponents, reducing the risk of injury. Dominance status depends on age and sex, with older animals usually dominant to young ones and males dominant to females. Young bulls gain superior dominance status over adult cows when they reach about 2 years of age.[19]

Cattle eat mixed diets, but prefer to eat approximately 70% clover and 30% grass. This preference has a diurnal pattern, with a stronger preference for clover in the morning, and the proportion of grass increasing towards the evening.[45] When grazing, cattle vary several aspects of their bite, i.e. tongue and jaw movements, depending on characteristics of the plant they are eating. Bite area decreases with the density of the plants but increases with their height. Bite area is determined by the sweep of the tongue; in one study observing 750-kilogram (1,650 lb) steers, bite area reached a maximum of approximately 170 cm2 (30 sq in). Bite depth increases with the height of the plants. By adjusting their behavior, cattle obtain heavier bites in swards that are tall and sparse compared with short, dense swards of equal mass/area.[46] Cattle adjust other aspects of their grazing behavior in relation to the available food; foraging velocity decreases and intake rate increases in areas of abundant palatable forage.[47] Cattle avoid grazing areas contaminated by the faeces of other cattle more strongly than they avoid areas contaminated by sheep,[48] but they do not avoid pasture contaminated by rabbits.[49]

In 2009, the National Institutes of Health and the US Department of Agriculture reported having mapped the bovine genome.[63] Cattle have some 22,000 genes, of which 80% are shared with humans; they have about 1000 genes that they share with dogs and rodents, but not with humans. Using this bovine "HapMap", researchers can track the differences between breeds that affect meat and milk yields.[64] Early research focused on Hereford genetic sequences; a wider study mapped a further 4.2% of the cattle genome.[62]

Behavioral traits of cattle can be as heritable as some production traits, and often, the two can be related.[65] The heritability of temperament (response to isolation during handling) has been calculated as 0.36 and 0.46 for habituation to handling.[66] Rangeland assessments show that the heritability of aggressiveness in cattle is around 0.36.[67]

Cattle have played a key role in human history, having been domesticated since at least the early neolithic age. Archaeozoological and genetic data indicate that cattle were first domesticated from wild aurochs (Bos primigenius) approximately 10,500 years ago. There were two major areas of domestication: one in central Anatolia, the Levant and Western Iran, giving rise to the taurine line, and a second in the area that is now Pakistan, resulting in the indicine line.[69] Modern mitochondrial DNA variation indicates the taurine line may have arisen from as few as 80 aurochs tamed in the upper reaches of Mesopotamia near the villages of ayn Tepesi in what is now southeastern Turkey, and Dja'de el-Mughara in what is now northern Syria.[70]

Although European cattle are largely descended from the taurine lineage, gene flow from African cattle (partially of indicine origin) contributed substantial genomic components to both southern European cattle breeds and their New World descendants.[69] A study on 134 breeds showed that modern taurine cattle originated from Africa, Asia, North and South America, Australia, and Europe.[71] Some researchers have suggested that African taurine cattle are derived from a third independent domestication from the North African aurochs.[69] Whether there have been two or three domestications, European, African, and Asian cattle share much of their genomes both through their species ancestry and through repeated migrations of livestock and genetic material between species, as shown in the diagram.[72]

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