You can only change ONE letter, AND/OR rearrange the letters currently available. The first word is:
WINS
goat
toga
stag
gust
gnus
guns
snug
(what else would gnus be?)
They would be wildebeests!
nags
guan
Birds resembling the curassows
gaur
probably the most powerful of all cattle - something like the Arnold of cattle :P
http://en.wikipedia.org/wiki/File:Bos_gaurus_male_münchen_2003.jpg
grue
A shudder of fear. As when faced with a pointy stick and a large pot of soup at the same time.
glue
something that binds things together, including kettles or bowl broken due to strong corrosive primordial broths :P
ague
A mediaeval illness like malaria. The recommended treatment was plenty of rest and lots of soup. No country nowadays officially admits to suffering from this illness.
gaun
present participle of gae. A key ingredient in the the soup that perpetuates ague in isolated areas of the antipodes.
naga
(people/ place/ culture.)
wow, never heard of ague. I'm learning a few things here!
gane
(to yawn)
That's the first time I had heard of or seen a picture of a gaur. What a fantastic animal!
rang
'cause I dunno any fancy words
grin
'cause I do.
grim
your prospects for winning LOTP
mair
A Scottish executioner. Don't try to stop me. :)
mare
@90, they are hulking beasts and pretty scary, wouldn't want to cross the path of a pissed off bull!
ream
what the bull would do to you if he caught you.
mire
what the bull would do after he had finished reaming you!