Aggressive towards new puppy

 A few things...

I think because of the dog's condition, their interaction will have to be closely monitored.  It sounds like the dog may have a lower tolerance, which in this case is explained by the condition.  You may have to step in on the dog's behalf.  The dog should not be "aggressive" to the puppy, but the new puppy doesn't get to rule the house, he needs to learn what the rules are from you.

However, I do think that some of what you describe is OK and natural.  It kind of depends on how often it happens.  Whenever I put a new dog in my house, there is some showing of teeth by Kenya.  Never an real aggression, there have never been dog bites or dog fights.  I allow my dogs to set some limits within reason.  Now if it's happening like every few minutes then that is too much.  Either the puppy is not getting it or the dog has too low a tolerance or both, and then you need to step in and set the rules.

bdbull

 Should we worry about this

In a word - no.

It is NORMAL for older dogs to correct puppies within reason.  In fact, she can do a better job of it than you can and can help ensure that the pup is "polite" to OTHER dogs she meets when she is older.

That said, if she is tired, ill, hurting... well then she won't have the patience for a puppy.  In any case, she and the puppy should have time away from each other, so that the pup gets rest and the older dog gets a break. 

bdbull

what can we do to make it easier on them?

Is either dog crate trained?  Crates are a very good tool, provided they are used wisely and kindly.  A crate would be very useful, not only for giving the older dog a rest from the puppy, but also for house training and ensuring that the pup does not chew on unsuitable items when you are not looking.  I would make sure that the puppy never goes near the older dog's crate, so that she knows she has somewhere to retreat to if she wants a rest - this may make her less snarky and should certainly make her feel more secure.

If they DON'T have crates, then I would make sure that there is an area (her bed for example) that the puppy is not allowed access to.  You can do this by physically blocking the area or simply by patiently and consistently moving the puppy away just before she gets too close. 

Liesje

I think because of the dog's condition, their interaction will have to be closely monitored.  It sounds like the dog may have a lower tolerance, which in this case is explained by the condition.  You may have to step in on the dog's behalf.  The dog should not be "aggressive" to the puppy, but the new puppy doesn't get to rule the house, he needs to learn what the rules are from you.

Agreed

 Some more thoughts - as I said, an older dog should IMO, be allowed to discipline a younger pup "within reason".  It's up to you and your common sense how much that is.  I would step in on behalf of the older dog and give them both a little "downtime" (in their crates?) if the puppy was being REALLY persistent and/or rambunctious.  This is for 2 reasons: one because it's simply unfair on the older dog (especially if she is unwell) and two - because I wouldn't want the puppy to practise these poor social skills, or end up getting hurt by the older dog when she really pushes it too far.  Both could lead to fear/aggression/reactivity problems with OTHER dogs later on.

 Thanks for the responses.  I think it's just normal behavior.  She has no problem with him as long as he doesn't nip at her.  His favorite thing to do is run up behind her and bite her back legs.  That would (and does) bother me too.

We will continue to closely monitor their interaction and hopefully it will get better as the little one gets older.

 What you really should be thinking about at this stage is enrolling the puppy in class - many progressive trainers and vets now recommend early class for puppies, so that you don't lose the socialization window (age 8-12 weeks).  Play with other pups is a great way to encourage bite inhibition, and lessens the chance that the pup will really irritate the old girl, or you, by being too mouthy with those sharp little teeth.  Plus they learn that all dogs are not as tolerant as their pack mates might be, or that some pups WILL play rough and like to tussle, while others will set you on your ear for doing the same things - in other words, they learn canine language.  Your older dog is exhibiting normal behavior, and in fact, is probably thinking why the heck did they go and get me this little whippersnapper to bring up?  However, older dogs are usually tolerant of pups to some extent, but will really tell them off once they hit 4-6 months of age.  We say the little one "runs out of puppy license:-)

 Way to dig up a month-old post (and not read it) to post a random picture and promote the website in your signature? 

In this case I do not think a muzzle is warranted, or a good idea. This dog is not showing any signs of aggression towards people, only towards an unruly puppy who bites its back legs. I think if someone were biting my back legs, I might be a little testy, too.

In many cases, signs of "aggression" can be signs of fear/insecurity. In these cases, while it is of course important to protect other people and other animals, simply hiding the "aggressive" dog away does nothing to resolve the fear/insecurity issues and can actually make them worse. It's always important to evaluate the dog's behavior on a case-by-case basis, preferably with the help of a professional who is highly skilled in canine behavior.

Just in case any lurkers out there are getting any ideas...