The most common and most likely answer to this crossword clue is the 8 letter word WHINNIES
I've seen this crossword clue in The Daily Telegraph
W
H
I
N
N
I
E
S
More clues leading to the result WHINNIES
Buddy explains!

The straight part
We know that "beastly noises" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case beastly noises = whinnies.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does WHINNIES mean?
WHINNIES noun- A gentle neigh.
- (of a horse) To make a gentle neigh.