feed the cat/dog/baby/child:

How would I say something like "I'm going to feed the cats."? I've heard both 'alimentar' and 'dar de comer' for 'feed'. I'm not really sure how to use 'dar de comer' though. Just 'Voy a dar de comer a los gatos'? And would you say it the same way for feeding children?

It is hard to tell when some alternatives are preferred in some countries, but here go my 3 pence:

"Alimentar" sounds rather technical; it is what you'd say in a Biology lesson, in a commercial, or when you talk about nutrition. "Dar de comer" is commonly used both with animals and people, but you have to use "a" with it.

walk the dog: I've read to use 'sacar a pasear'. How is that used? Do you need to use a conjugated form of 'sacar' or 'pasear'? Why are caminar or andar not used?

"Sacar (a pasear)" is commonly used in Spain, along with "Dar una vuelta". The second verb, like in English, is never conjugated (i.e. it is always "pasear"), so you only change "sacar". "Caminar" and "andar" are actions that beings do themselves, but you don't do on others in Spanish. It is like "to die": people die, but you don't die other people (you do, in other languages!): you kill them. In Spanish you walk, but you don't walk others. These things are not always logical; you have to accept them.

give the dog a bath: Do you use lavar or baño? And dar? Or just say 'Voy a lavar el perro.'?

Again, if you say "lavar el perro", it sounds as if the dog is an object; we use the preposition "a": "Voy a lavar al perro", "Voy a dar un baño al perro".

feed the cat/dog/baby/child:

How would I say something like "I'm going to feed the cats."? I've heard both 'alimentar' and 'dar de comer' for 'feed'. I'm not really sure how to use 'dar de comer' though. Just 'Voy a dar de comer a los gatos'? And would you say it the same way for feeding children?

It is hard to tell when some alternatives are preferred in some countries, but here go my 3 pence:

"Alimentar" sounds rather technical; it is what you'd say in a Biology lesson, in a commercial, or when you talk about nutrition. "Dar de comer" is commonly used both with animals and people, but you have to use "a" with it.

walk the dog: I've read to use 'sacar a pasear'. How is that used? Do you need to use a conjugated form of 'sacar' or 'pasear'? Why are caminar or andar not used?

"Sacar (a pasear)" is commonly used in Spain, along with "Dar una vuelta". The second verb, like in English, is never conjugated (i.e. it is always "pasear"), so you only change "sacar". "Caminar" and "andar" are actions that beings do themselves, but you don't do on others in Spanish. It is like "to die": people die, but you don't die other people (you do, in other languages!): you kill them. In Spanish you walk, but you don't walk others. These things are not always logical; you have to accept them.

female dogs - do people really use 'la perra'? I've only seen it used once, otherwise I've only seen 'el perro' and I didn't know if they were just generalizing and saying a male dog or what. Or if there is some kind of negative connotation with the use of 'female dog' as there is in English.

Bad as it may sound sometimes, people do say "la perra", although some people avoid this by saying the name of the female dog. And yes, "perra" means "bitch" in Spanish too.

clean the litter box: I've seen 'caja de litera' and 'caja de arena' for litter box. 'Arena' doesn't seem right to me though since we don't use sand. And for cleaning it, do people use limpiar?

"Litera" is a HORRIBLE word-by-word translation, and it will be unintelligible in countries where English doesn't have a strong influence, especially because "litera" means "bunk bed" in all Spanish speaking countries. "Caja de arena" sounds a lot better, if you ask me, although I've always heard (in Spain) "la caja del perro/gato/...". We use "limpiar" here, yes.

Cleaning up after dogs:

Lastly - how would you say clean or pick up dog poop from the yard? We have one of those long handled rake and pan things, would 'recoger' work? And what is a polite term for dog poop?

This one is more difficult, and probably more different depending on the country. "Recoger" is a good verb, and I don't know of any standard euphemism for "poop" in Spanish (there are some, but they are too posh), and apparently, "caca" remains the most common option. Spanish tends to avoid direct references to these sort of activities, and normally indirect explanations are preferred.

Thank you!

So, for walking a dog I could say
'Voy a sacar a pasear mi perra.' (I'm going to walk my dog.) Or
'Saqué a pasear mi perra.' (I walked my dog.) or
'Estoy sacando a pasear mi perra.' (I am walking my dog) or
'Saco a pasear mi perra casi todos los dias.' (I walk my dog almost everyday.)

If I used perra like in the examples above would it sound somewhat crude or make people want to laugh at me (even though they might be polite and not laugh out loud) because I've said something that sounds like a 'bad' or inappropriate word?

In English if I wanted to avoid using the word 'poop' I might say something like 'I'm going to clean up after the dog.' . Is there some way to say something like that in Spanish?

Thanks again!

'Voy a sacar a pasear a mi perra.' (I'm going to walk my dog.) Or

'Saqué a pasear a mi perra.' (I walked my dog.) or

'Estoy sacando a pasear a mi perra.' (I am walking my dog) or

'Saco a pasear a mi perra casi todos los dias.' (I walk my dog almost everyday.)

"Sacar a pasear" means "to take out for a walk", so it is not used in the progressive form, unless you are describing how you are leaving your house.

"Perra", when you refer to animals, should be OK to use.