A vacinação, a castração e a vermifugação são cuidados importantes.

Because all three are singular feminine nouns, so they normally take the definite article a.

• a vacinação
• a castração
• a vermifugação

In Portuguese, using the article is often more natural than in English, especially when listing general categories or procedures. English might say Vaccination, neutering, and deworming are important care measures, but Portuguese commonly uses the articles here.

They are feminine because nouns ending in -ção are generally feminine in Portuguese.

So:

• a vacinação
• a castração
• a vermifugação

This is a very useful pattern to remember:

• a informação
• a situação
• a alimentação

So if you see a noun ending in -ção, it is very often feminine.

The ending -ção often turns a verb into an abstract noun, similar to English -tion or -ing in some contexts.

Examples in this sentence:

• vacinar → vacinação = vaccination
• castrar → castração = castration / neutering
• vermifugar → vermifugação = deworming

So -ção is a very common noun-forming ending in Portuguese.

Because the subject is plural.

The subject is a list of three things:

• a vacinação
• a castração
• a vermifugação

Together, they make a plural subject, so the verb ser must also be plural:

• singular: é
• plural: são

Compare:

• A vacinação é importante.
• A vacinação, a castração e a vermifugação são importantes.

Because they refer to the three items together.

The sentence is saying that these three things are important forms of care.

• cuidados is plural because there is more than one care measure
• importantes is plural because it agrees with cuidados

So the structure is:

• subject: A vacinação, a castração e a vermifugação
• verb: são
• complement: cuidados importantes

Because importantes is agreeing with cuidados, not directly with the three nouns in the list.

Here:

• cuidados = masculine plural noun
• importantes = adjective agreeing with cuidados

So it stays masculine plural:

• cuidados importantes

If the sentence used a feminine noun instead, the adjective would match that noun:

• A vacinação, a castração e a vermifugação são práticas importantes.

Here práticas is feminine plural, so importantes still works because that adjective has the same form in masculine and feminine plural. But with an adjective like necessário/necessária, you would clearly see the difference:

• são cuidados necessários
• são práticas necessárias

Because the sentence describes a general fact, not a temporary condition.

• ser is used for identity, definition, classification, and general truths
• estar is used for temporary states, locations, and changing conditions

This sentence means that vaccination, neutering, and deworming are important kinds of care in general, so ser is the right verb:

• são cuidados importantes

Using estão here would sound wrong in normal usage.

Vermifugação means deworming, especially in veterinary or medical contexts.

It comes from the idea of eliminating worms/parasites. In Brazil, it is a normal and useful word, especially when talking about pet care.

Related words:

• vermífugo = deworming medicine / vermifuge
• vermifugar = to deworm
• vermifugação = deworming

For pet-related language, this is definitely a word worth knowing.

Yes, castração is commonly used in Brazilian Portuguese for animals, including pets.

In English, people often prefer softer words like spaying/neutering, but in Portuguese castração is very normal in veterinary and public-awareness contexts.

You may also hear:

• castrar = to neuter/castrate
• animal castrado = neutered animal

So even if it sounds stronger to an English speaker, it is standard usage in Portuguese.

They separate the items in a series:

• a vacinação
• a castração
• a vermifugação

This works much like English. In Portuguese, the comma before e is usually omitted in a simple list, so:

• A vacinação, a castração e a vermifugação...

is the normal punctuation.

Sometimes in headlines, notes, or very compressed style, yes. But in a normal full sentence, keeping the articles is more natural.

Natural:

• A vacinação, a castração e a vermifugação são cuidados importantes.

Less full, more list-like:

• Vacinação, castração e vermifugação são cuidados importantes.

The second version is understandable, but the first is more standard and smoother in ordinary prose.

São is pronounced with the nasal diphthong ão, which is one of the most characteristic sounds in Portuguese.

A rough guide:

• são sounds somewhat like sowng said through the nose, but that is only an approximation.

Important points:

• the ã is nasal
• the final o is not pronounced like a strong English oh
• the whole ending -ão is one nasal sound combination

You will hear the same ending in:

• não
• ação
• coração

For an English speaker, the main challenge is making it nasal rather than pronouncing it as two separate sounds.

Yes, but the given order is the most natural and neutral.

Standard:

• A vacinação, a castração e a vermifugação são cuidados importantes.

You could also say:

• São cuidados importantes a vacinação, a castração e a vermifugação.

But that sounds more formal or stylistically marked. For learners, the original order is the best one to use.

Most likely, yes. The combination of vacinação, castração, and vermifugação strongly suggests pet or animal care, especially dogs and cats.

Even without extra context, a Brazilian reader would very likely understand it as referring to animal care. The word cuidados here fits that context very naturally.