Medicul veterinar verifică microcipul, vaccinul și carnetul de sănătate.

Because Romanian usually puts the definite article at the end of the noun instead of using a separate word like English the.

So:

• medic = doctor / vet doctor
• medicul = the doctor / the vet
• microcip = microchip
• microcipul = the microchip

In this sentence, all of those nouns are definite, so they take the definite ending.

For masculine and many neuter nouns in the singular, that ending is often -ul.

Medicul veterinar is the standard full expression for the veterinarian or the veterinary doctor.

A few useful points:

• medic veterinar = veterinarian
• medicul veterinar = the veterinarian

Romanian normally puts the adjective after the noun:

• medic veterinar = veterinary doctor

So the definite article goes on the noun:

• medicul veterinar

You can also hear veterinarul in everyday speech, and it often means the vet, but medicul veterinar is the fuller and slightly more formal expression.

Verifică is:

• present tense
• 3rd person singular
• from the verb a verifica = to check / to verify

So it means:

• he checks
• she checks
• it checks

Here the subject is medicul veterinar, which is singular, so the verb is singular too:

• Medicul veterinar verifică... = The veterinarian checks...

Because these are direct objects of the verb a verifica.

In Romanian, just like in English, a verb like to check usually takes its object directly:

• checks the microchip
• checks the vaccine
• checks the health record/booklet

So Romanian says:

• verifică microcipul
• verifică vaccinul
• verifică carnetul de sănătate

No extra preposition is needed.

Because each noun is a separate definite thing:

• microcipul = the microchip
• vaccinul = the vaccine
• carnetul de sănătate = the health booklet/record

Romanian does not normally put one article at the beginning of the whole list the way English uses one the before a series. Instead, each definite noun usually shows definiteness on itself.

So this structure is completely normal:

• microcipul, vaccinul și carnetul de sănătate

Literally, it is something like the booklet of health.

Romanian often uses:

• noun + de + noun

where English might prefer:

• an adjective, or
• a compound noun

So:

• carnet de sănătate = health booklet / health record booklet
• carnetul de sănătate = the health booklet / the health record

Only the first noun gets the definite article:

• carnetul
• not carnetul de sănătatea

That is the normal pattern.

Two useful pronunciation points here:

• ă is a special Romanian vowel. It is somewhat like the vowel sound in the last syllable of English sofa, though Romanian pronounces it more clearly.
• ș is like English sh

So:

• și sounds like shee
• verifică ends with that ă sound
• sănătate contains ă twice

A rough learner-friendly approximation would be:

• și ≈ shee
• verifică ≈ veh-ree-FEE-kuh
• sănătate ≈ suh-nuh-TAH-teh

Yes, it matters, especially for articles and agreement.

In this sentence:

• medic is masculine
• microcip is neuter
• vaccin is neuter
• carnet is neuter

Romanian neuter nouns behave:

• like masculine in the singular
• like feminine in the plural

That is why in the singular they can look just like masculine nouns:

• microcipul
• vaccinul
• carnetul

So even though some of these nouns are neuter, the singular definite form still uses -ul.

Yes, Romanian word order is fairly flexible, but this sentence uses the most neutral and standard order:

• Subject + Verb + Object

So:

• Medicul veterinar = subject
• verifică = verb
• microcipul, vaccinul și carnetul de sănătate = objects

This is the most natural order if you are simply stating a fact.

Romanian can change word order for emphasis, but for a learner, this sentence is a good model of normal everyday structure.

Yes, but the meaning changes.

• un medic veterinar = a veterinarian
• medicul veterinar = the veterinarian

So:

• Un medic veterinar verifică... = A veterinarian checks...
• Medicul veterinar verifică... = The veterinarian checks...

Use un when the person is not specific yet, and -ul when you mean a specific, identifiable vet.