Ch3 - Bull
Bull is an adult male of cattle. In Europe, it descended from aurochs, a species long extinct. In other parts of the world, cattle originated from various other species, such as European bison or buffalo.
Cattle were domesticated around 6-7 thousand years ago in Asia. Since then, cattle breeding has developed significantly. Nowadays, there are a lot of different breeds of cattle kept for milk, meat, leather, fat, or because of their strength.
Cows and bulls are typical ruminants – they are herbivores with long legs that end in hooves. They also have thick fur and horned skulls.
One of the more interesting things about ruminants is their digestive system. Their stomachs can hold up to 200 liters of food and consist of 4 compartments: each of them digests food differently. What is more, even bacteria living in the animals' digestive system help with processing food. Cows eat nothing but plants, rich in cellulose, which is hard to digest. They manage to survive in spite of it, all thanks to the helpful bacteria and the complicated structure of bovine stomachs.
The offspring of a cow and a bull is called a calf. Eventually, it grows and becomes a heifer (young cow) or a bullock (young bull).
Among the most interesting cattle breeds you will find Ankole-Watusi. It is extremely resistant to high temperatures and parasites. The species also has large, distinctive horns. Ankole-Watusi are bred by the Maasai people living nearby Lake Victoria in Africa. The cattle are bred for dairy, meat, leather, and their manure, which is used as fuel.
Wagyu are the most expensive cows in the world. They are bred mainly in Japan, near the city of Kobe. One kilogram of Wagyu beef can cost up to several hundred euro. Wagyu cows are under special care. In order to ensure their good health condition and lack of stress, breeders provide them with daily massages and a small dose of beer, to relax. This special treatment is supposed to be the explanation behind the outstanding taste and healthy qualities of the Wagyu beef.
Despite the lack of personal masseurs, title of the World’s Happiest Cows should definitely go to animals in India. The cows living there can go wherever they please, nip food from the local market stalls and block the streets – and no one will blame them. In Indian culture, cows are treated with respect, and beef is eaten very rarely.
Hindus believe that 300,000 of the most important deities inhabit a cow, and that it is one of the "mothers of humanity" since it feeds people with its milk. This approach originated in ancient times, when the diet of peoples travelling this land was based on dairy. Killing a cow for its meat would deprive people of its milk, so with time, the cow became inviolable, and this approach still holds.
Another notable species of cattle is yak – it inhabits the cold grasslands of Himalaya in Tibet, India and China. Yaks live as high as 6000 meters above sea level, where the temperature is around 0°C in summer and can drop to -50°C in winter. This is why yaks have coats so long that they can sometimes reach the ground. Wild yaks live in small groups, in the mountains. Domesticated yaks are pack animals, which means they serve to carry heavy cargo. They are also bred for fiber and milk.
Dzo is a hybrid of yak and domestic cattle, valued for its enormous strength and endurance. Moreover, Dzo provides more meat and milk. You can find it in Nepal and Mongolia, where people use them as draft and pack animals.
The experiment conducted in 1969 proved that cattle can "predict" weather, or more precisely, changes in the air pressure. When it starts to drop, cows tend to give less milk. These animals can sense pressure changes long before they are reflected in the weather.
Cattle tend to have calm temper. Usually, they are equally friendly and social towards other cattle, as well as towards humans. Sometimes though, they can be restless. It is important to treat cattle gently and calmly, but it may become necessary to soothe animal’s nervous fit with the use of special equipment. A nose-ring can serve this purpose, since cattle’s noses are very sensitive.
Another recognizable piece of "jewellery" for cattle is earrings allowing to place each animal in the identification database.
Build
To build this model, you will need LEGO Education WeDo 2.0
Explore
The model represents a bull jumping out and ramming the pen’s gate on the way.
Any movement in front of the gate will be the starting signal for the program.
The robot uses several electronic components.
1. The hub provides power and controls both elements attached to it, in accordance with the program created.
2. The motor propels the transmission gear, which draws the bull out and opens the gate.
3. The motion sensor detects movement in front of the gate and sends a signal for action.
1. The bull is firmly placed on a mobile base. Just like a real bull, this model has horns pointed forwards and a tail.
The movement of the bull and the gate is synchronized.
1. The motor propels the axle with two cogwheels. When the program is turned off, you can adjust the bull's position by means of a regulator.
2. The rotating gears push the gear racks and the joint base. Thus, they make the whole base move forwards or backwards.
3. The beams responsible for pushing the gate hinges are on the other side of the base.
Both the bull and its base move on a special rail.
1. Two long bricks on each side ensure that the base moves only forwards or backwards.
2. The rail is paved with smooth tiles, so the base can slide easily.
1. Thanks to synchronization of the base and the gate, the bull looks like its ramming the gate when moving. When retreating, the gate is closing behind it.
Program
Let’s program the robo-bull.
