Animal spaying/neutering

[zeebo76]

I know we've all been tired of our animals having too many babies at one point or another.  I dunno about any of you but for me, it feels super bad to put down an excess puppy I just can't take care of - so if I can have an animal spayed/neutered in real life, why not in Rimworld?

It would be a simple medical operation that would eliminate future pregnancies in females, or eliminate a male's ability to...  Y'know...  Do their thing.

[willywonkasrevenge]

I second this request. Seems like it would be easy to implement in vanilla and would add to realism and immersion. If you don't want to spay/neuter, then don't choose it from the "Operations" menu.

[Alenerel]

I always missed some kind of animal limit. I don't think neutering works, its just killing the puppies with extra steps and wasting medicine

[Umaro]

A simple solution would be to zone males and females. No interactions, no babies.

That way, you can even keep the females for when you do want babies, and use only the males to fight threats (keep at least one for future pregnancies).
When you do want babies, don't forget to sort the newborns, before they come of age.

it feels super bad to put down an excess puppy I just can't take care of

I am trying to pin point what feels bad in order to provide the best solution, if any.

Is it that you can't take care of them in the first place?
Zoning.

Is it because your colonists have to do it and the work to meat ratio for babies is not inter... I mean because you don't want them to perform such a sad act?
What if we think of it as part of the natural cycle of thing? Some species have a lot of offsprings because there is a natural selection and most of them will be eaten, enough will survive, but without that the ecosystem might crumble.

As a matter of fact, in Rimworld animal babies are a prey of choice for wild animal predators on the map. You can release them outside your base and let nature do her thing...
Or, to make their short existence useful to the colony, you can use them as bait to lure said predators into an animal killbox. That way you can hunt carnivores without having to run after them at the edge of the map, especially during winter when food is scarce for them.

Or we can just use them to feed our animals. It's not elegant but it is efficient work wise to zone them somewhere without food to starve to death (for example in a special freezer), and your carnivorous animals can eat them later. No need to slaughter/butcher/haul/cook/haul.

Lastly, I guess there is a solution for herbivors, you can have one pawn form a caravan with them, go to the map next to your colony, and stay there. Forever. Animals can graze for free in a caravan (depending on where you are on the globe obviously), so they will give birth there, babies will grow, and maybe you can even take them back later to sell them, or in case of an emergency call the caravan back to fight againt a difficult raid (hopefully they will come back fast enough and attack the raiders from behind). The shepard you send for this task will live his life as an ermit so your animals can have a better life. From time to time send another colonist with some food so he doesn't starve. On a horse it will be very fast. Note that a caravan has a chance to be ambushed.

Or, or... you can just release them from the caravan into the wild. Free.
But I digress, your problem is the constant pop up of babies...
Solution is simple, zoning tool. Or a mod.

It would be a simple medical operation

From a balance point of view, I wonder if this can be an issue: It provides a medical operation that would allow colonists to train their medical skill without a "drawback". There is already the operation "Euthanize by cut" that uses one herbal medicine to put down a pawn in a humane manner (aka not slaughtered. Maybe that's a solution you'd be ok with, and it does train your doctor as well as your grower (who plants and harvests healroots)). But in this case of euthanasia, the pawn dies, and a dead pawn on the map (whether it belonged to the colony or a wild animal) increase the wealth of the colony, which is used in other mechanics, as to calculate the threat of next raid.
In your suggestion, that's one "free" operation per animal (or per male, so half the animals). A mod would be good for this, with maybe some fun options (like a loss of consciousness/wilderness, so males deal less dps in fights, but require less handling overall).

Edit: Found 3 mods:
https://steamcommunity.com/sharedfiles/filedetails/?id=1501449584&searchtext=neuter
https://steamcommunity.com/sharedfiles/filedetails/?id=902186027&searchtext=animal
https://steamcommunity.com/sharedfiles/filedetails/?id=751049133&searchtext=neuter