siikuhi wo musisuru wake ni ha ikanai.

飼育費を無視するわけにはいかない。 is read:

しいくひ を むしする わけ には いかない。

In normal Japanese writing, it would usually be written without spaces:

飼育費を無視するわけにはいかない。

飼育費 means the cost of raising or keeping animals.

It breaks down like this:

• 飼育 = raising, breeding, keeping, rearing animals
• 費 = expense, cost

So depending on context, 飼育費 could mean things like:

• pet care costs
• livestock raising costs
• animal maintenance expenses

Because 飼育費 is the direct object of 無視する.

• 無視する = to ignore, disregard
• What is being ignored? 飼育費

So:

• 飼育費を無視する = to ignore the raising/keeping costs

This is a standard use of を to mark the thing directly affected by the verb.

Yes, but in this sentence it is probably closer to:

• disregard
• leave out of consideration
• fail to take into account

With something like costs, 無視する usually does not mean pretending not to see them physically. It means not considering them when making a decision or judgment.

So 飼育費を無視する is more like:

• ignoring the cost factor
• brushing aside the expense
• not taking those costs into account

This is a very common grammar pattern:

Verb dictionary form + わけにはいかない

It means something like:

• cannot just do ...
• cannot bring oneself to do ...
• cannot do ... because of circumstances, responsibility, common sense, social reasons, moral reasons, etc.

So in this sentence:

• 無視するわけにはいかない

means:

• one cannot ignore it
• it would not be acceptable to ignore it
• ignoring it is not really an option

The important nuance is that this is not just physical inability. It suggests some reason that makes the action unacceptable or unrealistic.

By itself, わけ often means:

• reason
• logic
• circumstance
• conclusion

But in わけにはいかない, it is best to learn the whole expression as a set phrase.

So while わけ has its own meaning, in this sentence you should mainly recognize:

• Vる わけにはいかない = cannot do V for some reason

Trying to translate each word too literally can make it harder than necessary.

In わけにはいかない, the は adds emphasis or contrast, and the whole thing functions as a fixed pattern.

So:

• わけにいかない would sound incomplete or unnatural in standard usage
• わけにはいかない is the normal form

You do not need to analyze に and は too separately every time. It is more useful to memorize the whole grammar pattern:

• するわけにはいかない
• 行くわけにはいかない
• 断るわけにはいかない

Historically, yes, it comes from 行く, but in this expression it is not functioning as the ordinary literal verb to go.

In わけにはいかない, いかない is part of a fixed grammatical expression meaning something like:

• it will not do
• it cannot be allowed
• it is not feasible/acceptable

That is why it is often written in kana as いかない, not 行かない.

So in this sentence, do not read it as physical movement.

Good question. These are similar, but not identical.

無視できない

This often means:

• cannot ignore
• too important to ignore
• impossible to overlook

It can sound more like a factual or logical statement.

無視するわけにはいかない

This adds the nuance that:

• there are reasons you should not ignore it
• it would be irresponsible or unacceptable to ignore it
• ignoring it is not really an option

So わけにはいかない often feels more tied to judgment, responsibility, or circumstances than plain できない.

They are close, but the nuance is different.

無視してはいけない

This means:

• must not ignore
• do not ignore

It sounds more like a rule, instruction, or prohibition.

無視するわけにはいかない

This means:

• we cannot ignore it
• it would not be reasonable/acceptable to ignore it

This sounds less like someone giving an explicit rule and more like the speaker recognizing a constraint or obligation.

So:

• てはいけない = direct prohibition
• わけにはいかない = cannot do that, given the situation

Yes. Japanese often leaves the subject unstated when it is obvious from context.

So 飼育費を無視するわけにはいかない。 could mean:

• I cannot ignore the rearing costs.
• We cannot ignore the rearing costs.
• One cannot ignore the rearing costs.

The exact subject depends on the surrounding context.

It sounds fairly neutral to somewhat formal.

It would fit well in:

• writing
• discussion
• explanation
• reports
• articles
• presentations

It is more formal and thoughtful than something very casual, but it is not extremely stiff or overly literary.

They are almost certainly added for learning purposes.

Normal Japanese is usually written like this:

飼育費を無視するわけにはいかない。

Japanese does not normally use spaces between words the way English does. Textbooks and study materials sometimes insert spaces to make the structure easier to see.

A very useful related pattern is:

Verbない + わけにはいかない

This means:

• have to do ...
• cannot avoid doing ...
• cannot not do ...

For example:

• 行かないわけにはいかない = I have to go / I cannot avoid going
• 払わないわけにはいかない = I have to pay

So:

• 無視するわけにはいかない = cannot ignore it
• 考えないわけにはいかない = cannot avoid thinking about it / have to consider it

This pair is worth learning together.