Vi må veie hunden og notere vekten før dyrlegen vaksinerer den.

Because må is a modal verb, and in Norwegian modal verbs are followed by the bare infinitive without å.

• vi må veie = we must weigh
• vi kan komme = we can come
• vi skal dra = we will / shall leave

So after må, you use veie, not å veie.

Hunden is the definite form of hund.

• en hund = a dog
• hunden = the dog

This sentence is talking about a specific dog that both speaker and listener already know about, so Norwegian uses the definite form hunden.

Here, vekten means the weight, referring to the specific weight of that dog.

• vekt = weight in a general sense
• vekten = the weight

In this sentence, they are not talking about weight as a general concept, but about the actual measured weight of the dog, so vekten sounds natural.

Yes. They are closely related in meaning:

• å veie = to weigh
• vekt = weight
• vekten = the weight

So the sentence literally has the idea:

• we must weigh the dog
• and note down the weight

This kind of verb/noun relationship is common in Norwegian, just as in English with weigh and weight.

Because once hunden has already been mentioned, Norwegian often uses a pronoun instead of repeating the noun.

• hunden is a common-gender noun
• the pronoun for it is den

So:

• dyrlegen vaksinerer den = the vet vaccinates it

This is very similar to English, where we would usually say the vet vaccinates it rather than repeating the dog.

Because den is the normal pronoun for a noun like hund when you are referring to it grammatically as a noun and not emphasizing biological sex.

• den = it
• ham = him
• hun = she

In everyday Norwegian, animals are often referred to as den unless the sex matters or the speaker wants to personalize the animal more strongly.

So dyrlegen vaksinerer den is the neutral and standard choice here.

Because dyrlegen means the veterinarian / the vet, referring to a specific vet in this situation.

• en dyrlege = a vet
• dyrlegen = the vet

Since the sentence is about the vet who will vaccinate the dog, Norwegian uses the definite form.

Vaksinerer is the present tense of å vaksinere.

• å vaksinere = to vaccinate
• vaksinerer = vaccinates / is vaccinating

So:

• dyrlegen vaksinerer den = the vet vaccinates it

In Norwegian, the present tense often covers both the simple present and, depending on context, something close to the English present progressive.

Because notere is coordinated with veie after the modal verb må.

The structure is:

• vi må veie hunden og notere vekten

This means:

• we must weigh the dog and note the weight

After må, both infinitives appear without å:

• må veie
• må notere (with må understood after og)

So the full underlying idea is:

• Vi må veie hunden og (må) notere vekten

Før means before and introduces a subordinate clause.

• før dyrlegen vaksinerer den = before the vet vaccinates it

So the sentence has:

• main clause: Vi må veie hunden og notere vekten
• subordinate clause: før dyrlegen vaksinerer den

This tells us when the weighing and noting must happen: before the vaccination.

Yes, før introduces a subordinate clause, and Norwegian subordinate clauses follow subordinate-clause word order.

In this sentence, the clause is:

• før dyrlegen vaksinerer den

That looks similar to English: before the vet vaccinates it.

A very important thing to know is that in Norwegian subordinate clauses, elements like ikke usually come before the verb:

• før dyrlegen ikke vaksinerer den would be the subordinate-clause pattern

Compare that with a main clause:

• Dyrlegen vaksinerer den ikke

So even though this sentence does not contain ikke, it is a good example of a subordinate clause introduced by før.

Yes. Notere vekten literally means note the weight or write down the weight.

Depending on context, natural English translations could be:

• note the weight
• record the weight
• write down the weight

All of these fit the Norwegian phrase well.

No. You may also see veterinær.

• dyrlege = vet / literally animal doctor
• veterinær = veterinarian

Both are correct, but dyrlege is very common in everyday speech and easy to understand. In this sentence, dyrlegen is a perfectly natural choice.