Increasing population led us to the most cruel system which could be ever created. Looking at the numbers of farmed animals killed in 2019 it is obvious, there cannot be any ethics behind this procedure.
It starts form artificial insemination, living in small space or cages without ability to move and realize the basic needs, often long lasting transportation to the slaughterhouse.
In this process, animal are not treated as alive creature but as a thing and living in a pain and stress are common.
In 2019 about 220 million of farmed animals were killed per day, what gives 80,3 billion per year.
According to data provided by FAO , about 80 billion of farmed animals were killed in 2019.
It is not the end. The study based on FAO data, presents estimates of the fish killed globally in fishing and fishing farming 
- 790 – 2,300 billion fishes were caught from the wild for 2007-2016
- 970 – 2,700 billion fishes were caught from the wild for 1999-2007
- 460 – 1,100 billion fishes were caught to make fishmeal and oil for 2007-2016
- 51 – 167 billion farmed fishes were killed for food in 2017
- 250 – 600 billion farmed crustaceans were also killed for food in 2017
The numbers should be still increased by the number of wild animals, cats and dogs slaughtered for meat .
Taking into consideration all the animals killed across the world we get average even a 1 billion  per day.
Can You imagine that?
Just wonder if there is any chance, that these numbers might be linked to the animals welfare, sustainable production methods, keeping ecosystems in balance?
The general truth is one. Milk is for babies and females of each specie have suitable milk to nourish their young.
Human is the only animal which consumes the other species’ milk, also as adult. There are many research, claiming the pros and cons of drinking milk .
By using the key words we can find many research related to this topic.
There is no magic behind. Each female (also woman) has milk while having a baby. In a dairy industry, there is no time for maternity. Male calves are by-product and are used for veal, females are used for the same purpose what their mothers.
From the beginning, calves consume the milk substitutes, as milk is taken for humans. Cows are artificially inseminated shortly after their first birthdays, lactate for 10 months and inseminated again. After about 5 years when their productivity goes down and they became a part of meat industry. Normally they could live about 20 years.
During ages we got used to consume the dairy products.
Is it right ? Is it worth? Can we get the same based on plants?
Egg farming is a standard which involves about 7 billion of the layer hens across the world . Kept in cages, on very limited space, without ability to fulfill the basics needs.
A standard tool used in the egg industry were the “battery cages”, providing the floor space of about 45×61 cm for about 8 hens. However the standard “battery cages” were banned in EU in 201 2  the alternative is the cage providing space of 750 cm2/ hen what is equal to (0,075m2).
Can You imagine being a layer hen, locked for 2 years, on the space of 0,075m2, with tens of thousands hens? 
Hens are very social, intelligent, as the other animals. They have the abilities to learn like dogs, research claim also emotional abilities, especially when the hens take care of the chicks. The best is to keep up to 20 hens in the flock.
Imagine keeping 10-20-30 thousand in limited space?
Dark practice of this industry:
– after efficacy drop hens are killed for meat,
– while kept on small space the hens become aggressive and tend to cannibalism- to limit an aggression results, their beaks are trimmed,
– like in a dairy industry male chicks are useful. The standard procedure is grinding the 1 day male chicks (one of the chick culling methods) 
One more fact about mass farming.
Humans take antibiotics when get sick. Animals get it to prevent disease. Based on data from 2017, in some countries up to 80 % of antibiotics were used in animals industry and agriculture .
What are the consequences?
- by eating meat and meat origin products humans supplement antibiotics what leads to antibiotics resistance,
- animals excrete antibiotics in feces and urine, so it comes back to the environment;
The animals exploitation is more:
- animals testing  and vivisection [11.1]
- fur industry 
- fish farming
- entertainment (circus , hunting for trophies  & tourism)
- illegal wildlife trade
- tradition, believes, ceremony and religious use;
I really believe the numbers could be much lower.
These industries are the huge economy structures giving jobs to many people. It is impossible just to stop it right away. It is a process that requires planning and time, but if we start planning today maybe in 5 or 10 years the better future will loom on the horizon.
- at the biological level we are all the same- we feel pain and fear,
- animals deserve respect and rights,
- commercial farming means suffering under poor conditions (small space, high level of population density, inability to realize the basic needs),
- all the animals have ability to learn, have the cognitive abilities and ability to build relations,
- animals welfare should be a priority, especially that they give up their life for us;
Can You imagine how much natural resources we use to feed all these animals?
This is another story, as only Aware choice is our future.
 Food and Agriculture Organization of United Nations/ http://www.fao.org/faostat/en/#data/QL (Region: World + (Total), Element: Producing Animals/Slaughtered, Items Aggregated: Meat, Total > (List), Year: 2019 > file type XLS)
 https://www.four-paws.org/ 10 million of cats and dogs per year in Southeast Asia
 https://www.britannica.com/topic/large-numbers-1765137/ Billion in American nomenclature & thousand million/ milliard in British nomenclature (109/9 zeros)