This number seems a little bit off. About 900 million pigs are slaughtered in Asia per year [1] That's 2.5 million dead pigs a day. Since we need live animals to breed more for killing them and it takes time before they are killed, this suggests that at any given time more than a billion pigs are alive in Asia.
But good thing that we sterilized those 150000 dogs, anything else would have been inhumane [2]
According to a random page I found online, pigs are typically slaughtered at 5-6 months old, so assuming a stable population, you'd expect the number of living pigs (raised for slaughter) at any time to be 42%-50% of the yearly amount, so 375,000,000 - 450,000,000 going purely off of your 900,000,000 figure, making 500,000,000 a reasonable estimate, no?
While traveling SE Asia I didn't see that very often.
Besides in some rural areas (and even there), dogs turned into pets as in western "civilization" and their owners didn't want to eat them anymore.
When I was in Hanoi in 2010, in the central districts as unrural as you can get in Vietnam, skinned dog carcasses were hanging at a number of markets. If westernization has had an impact, it must be more recent than that. I’m curious to go back and see for myself.
But good thing that we sterilized those 150000 dogs, anything else would have been inhumane [2]
[1] https://faunalytics.org/global-animal-slaughter-statistics-a... [2] Sorry, I'm bitter.