La bestŝirmejo kontrolis la voston kaj registris la rason kaj temperamenton.

Because -is is the Esperanto past-tense ending.

So both verbs are in the past:

• kontrolis = checked
• registris = recorded / registered

A useful thing for English speakers is that Esperanto verbs do not change according to the subject:

• mi kontrolis
• li kontrolis
• ili kontrolis

They all use -is for the past.

The -n marks the direct object in Esperanto.

These are the things affected by the actions:

• the shelter checked the tail
• it recorded the breed
• and the temperament

In Esperanto, the noun keeps its normal noun ending -o, and then adds -n:

• vosto → voston
• raso → rason
• temperamento → temperamenton

So -on here means noun + accusative.

Because la bestŝirmejo is the subject, not the direct object.

It is the thing doing the actions:

• it checked
• it recorded

Only the direct objects take -n here. The subject stays without it.

It is a compound word:

• best- = animal
• ŝirm- = shelter, protect
• -ej- = place meant for something
• -o = noun ending

So ŝirmejo is a sheltering place, and bestŝirmejo is an animal shelter.

This is very common in Esperanto: several roots are combined into one word.

-ej- is a suffix meaning place for, place where something happens, or place used for something.

So:

• lerni = to learn
• lernejo = school, a place for learning

And here:

• ŝirmi = to shelter/protect
• ŝirmejo = shelter, a place for sheltering

It is one of the most useful Esperanto suffixes to learn early.

La is the Esperanto definite article, meaning the.

Esperanto has only one article of this kind, and it does not change for gender, number, or case.

In la rason kaj temperamenton, the single la can cover both nouns:

• the breed
• and the temperament

So this is normal. You could also say la rason kaj la temperamenton, but repeating la is not required.

The two kaj words connect different things.

The first kaj connects two verb phrases:

• kontrolis la voston
• registris la rason kaj temperamenton

So the shelter did two actions.

The second kaj connects two nouns:

• la rason
• temperamenton

So those are two things that were recorded.

Not completely. Esperanto word order is more flexible than English because the -n ending helps show what is the object.

Still, this sentence uses the most normal and beginner-friendly order:

subject + verb + object

That is why it feels straightforward:

• La bestŝirmejo = subject
• kontrolis / registris = verbs
• la voston / la rason / temperamenton = objects

Other word orders are possible in Esperanto, but this one is the most natural in ordinary prose.

Ŝ is pronounced like English sh in ship.

So bestŝirmejo starts with something like best-shir-.

A rough English-friendly pronunciation would be:

best-shir-MEY-o

The stress in Esperanto normally falls on the second-to-last syllable, so the stress is on MEY here.