It baffles the mind that people decry the death of a dog while munching a burger. Cows (or chickens, for that matter) are not less precious than dogs, and yet the vast majority of us eat as much and as many of them as they can afford.
You can feel that way, and that's fine, but people are allowed to decide what they do or don't find precious. They are allowed to rank species and members within a species in order of most to least precious. There's no inherent rule that all life must be valued the same. Would you not be more sad about a human child dying over a cow? Would you not be more sad about a loved one dying about a random person you don't know a few thousand miles away?
By extension, what makes cows more precious than 800 lb. of algal scum? Heck, the scum at least is reducing CO2 content; cows support global warming.
Who's precious now???
Additionally, your examples are passive. A more appropriate comparison would be "Would you not be more sad about killing a human child instead of a cow?" Of course you would be! But what if you didn't have to do either?
They reproduce faster then us so puppies are able to get cuter then babies over generations and thus they are out competing us.
That's why they're called "breeds", because humans bred them.
They're bred for cuteness, violence, but mostly they're bred for profit.
The "pet industry" is a rapid growth segment of the economy. If a pet is "part of the family", then isn't the "pet industry" basically a slave trade?
It's a 1000x speed up to have humans picking out the cute ones and deliberately forcing this forward to make money.
You have to realize that it's our own instincts driving this forward and if it detriments humanity then the traits of "seeking profit" or "seeking cuteness" become subject to natural selection. These traits will go away with time.
If you had to choose between a family member dying or a totally random person dying, even though objectively they're both just humans, you're going to kill the random person, because you have feelings and emotions, and they are part of the equation. For the same reason you'd kill the random person, people would kill the cow, and want to save the dog.