Experienced and professional animal trainer provide their insights in answering this question :
A. This is a condition called “pattelar luxation” – the knee cap basically go sideways causing severe lameness and hopping. it needs to be evaluated by a vet, but if it is not painful it is usually recommended not to do surgery. if it is painful usually surgery to repair the condition is advised.

How to Identify Common Pet Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced pet care professionals :

If your dog is suddenly limping on its back leg, it is important to have them seen by your veterinarian as soon as possible. There are many possible causes of sudden limping in the back leg of dogs, including a ruptured ACL, strain and sprains, IVDD, fracture/dislocation and iliopsoas muscle injury.
Weakness in back legs of dogs can be caused by a variety of things, including myasthenia gravis, heart problems, anemia, hypothyroidism, and Addison`s disease.
Sudden onset of collapse can be secondary to a variety of disorders including spinal cord injury, orthopedic disease, or systemic illness. This sudden hind-leg weakness may be a sign of a disease that requires prompt attention from your regular veterinarian. Or even a trip to the emergency room.
The problem of a dog`s leg bending is the result when many types of vitamins such as Vit D3 Vit A, Vit B, Vit C, or many minerals such as calcium and phosphorus are deficient. Sometimes the amount of calcium-phosphorus, and vitamins is changed in the puppy`s body, leading to malnutrition.
Treatment of Back Leg Weakness in Dogs

Surgery might be recommended for many conditions, but for others such as degenerative myelopathy, intervertebral disc disease, Wobbler`s syndrome, cancer, or Cushing`s disease, medical management may be preferred. Wobbler syndrome can also be managed with anti-inflammatory drugs.

If you know something is wrong but the lameness is not obvious, look for shortening of the stride on one leg, bobbing or lifting the head when placing a particular limb, or dropping the hip or shoulder. Also watch for abnormalities lying down or getting up, swelling, or signs of pain.
In general, gradual onset limps in dogs are caused by an underlying, chronic or degenerative condition, such as osteoarthritis or dysplasia. Sudden onset limps, on the other hand, are usually caused by an injury or trauma. Just because your dog has a gradual limp does not mean you should put off making an appointment.
Sometimes limping will go away on its own, especially if you provide some at-home support like a brace. Other times limping may be a sign of a more serious injury or condition that will require veterinary intervention.
When a dog loses a companion, two- or four-legged, he grieves and reacts to the changes in his life. Dogs alter their behavior when they mourn, much like people do: They may become depressed and listless.
The healing time for a broken leg in a puppy is relatively short (2 to 4 weeks). Younger dogs have more bone building cells and are growing anyway, so their bones are constantly remodeling. For adult dogs, the healing time for a broken leg is 6 to 12 weeks.
The legs are bent and not straight. The hindquarters are the back end of the animal. The back legs of a dog should be straight and not bowed in or outward. This Mastiff puppy shows a good back end.
A dog`s inability to walk is typically due to either a problem with the dog`s joints or issues with his spinal cord. Arthritis is probably the most common reason for a dog`s inability to walk. It often develops with age, but can even occur in very young dogs.
Hip dysplasia can affect anyone at any age. Although it is believed to develop around birth, a child with mild dysplasia may not have symptoms for years, or even decades. Hip dysplasia in babies is known as infant developmental dysplasia of the hip (DDH).
Dogs who have hip dysplasia may sway back and forth when they walk. They may also have a bunny-hopping gait or may stand flat on their back feet. All of these potential gait issues are related to the pain they feel when they suffer from hip dysplasia.
The key is to overload the affected muscles to strengthen them, but it needs to be done gently, carefully, and gradually. Dog physical therapy is an ideal way to first help with the recovery process and then to continue to strengthen the muscles after healing.
Causes of your puppy Limping

Heading the list are muscular sprains and strains, therefore there`s no need to panic if your puppy limps initially get some rest, and if the matter persists, get your puppy checked by the vet. Trauma is another biggie, and as young bones are soft, this could mean fractures.

Since puppies have bodies that aren`t as strong as adult dogs, they can unintentionally overexert or injure themselves. Muscle strains are one fairly common injury among young pets. Puppies` muscles aren`t fully formed yet and can be easily hurt.
With support from orthopedic braces, a healthy diet, regular exercise, as well as homeopathic support, your older dog may have many happy and healthy years ahead, free of back leg collapse. Talk to your vet and ask if a hip brace may alleviate your older dog`s hind leg weakness.
The truth is dogs and cats can function extremely well after amputation. In fact, most are just as mobile after surgery as they ever were; especially in the case of prolonged pain and discomfort. Although there is an adjustment period, many can live a happy, active life.
Mild Dog Limping

A mild limp means your dog is still using the leg but not putting as much weight on it. If your dog has just developed a mild limp, but appears comfortable and healthy in all other ways, it`s not unreasonable to encourage them to take it easy for a few days and see what happens.

If the limp doesn`t begin to resolve itself, is becoming worse, or is accompanied with whining or yelping, it`s time to call your vet or visit your nearest emergency vet. Your veterinarian has the training and knowledge to best determine the cause and severity of your pup`s pain.
Diseases & Conditions. At one time or another, all children have episodes of limping. Usually the limp is caused by a minor injury and will get better by itself.
Causes of Limping in Puppies

In fact, the most common cause of puppy limping is a simple muscle sprain or strain, which can be treated with rest. Try letting your puppy disengage in activity for some time to see if the problem improves and if it doesn`t, take him to the vet for a checkup.

If the limp doesn`t resolve itself within 48 hours, becomes worse, or if your pup is whining or yelping, it`s time to call your vet to book an examination for your pet. Your veterinarian is best equipped to determine the cause and severity of your dog`s pain.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Q. My Bulldog puppy growls, barks and even tries to bite me when I say “no” to him. What can I do?
ANSWER : A. First, avoid scolding him and acting aggressively towards him if you don’t want him to be acting aggressively towards you. There are other methods you can use to communicate to your dog that you don’t want him to continue doing what he is doing. I recommend you stop telling him “no”, scolding him, or raising your voice at him. Everything coming from you should be 100% positive and 100% calm.

Try to figure out ways to clearly communicate what you want to your dog. If you want your dog to leave something or someone alone, I strongly suggest teaching your dog commands like “leave it”. Here is a link to a video in which I explain how to do it:

www.youtube.com/watch?v=R1TS5nA7z5Q

Another thing I suggest you use is a no-reward marker. This clearly communicates when your dog has done something wrong. No-reward markers have to be introduced during your training sessions. You should be doing at least three training sessions per day, that are something like 3-10 minutes long (working on different things each training session). If you are teaching your dog something BRAND NEW, do not use the no-reward marker, as you do not want to discourage your dog from performing behaviors for you. Use the no-reward marker for known behaviors only. Here is another helpful video about this:

www.youtube.com/watch?v=sdU5a6fXKlg

Lure each new behavior (as shown in the video) using high value treats. Let’s say you’re working on “down” which is a behavior your dog knows fairly well. Present the treat to your dog. Ask your dog to “down” (only ask once). If he does not go “down” immediately, say, “uh-oh” or “eh-eh” in a gentle tone, and then place the treat behind your back. This communicates to your dog that they did something to make the treat go away.

After you place the treat behind your back to show your pup “that was wrong” you need to communicate to your pup “let’s try again” by getting your pup to walk around for a second, and then start the behavior all over again. If your puppy is very young, chances are you haven’t taught him a solid “down” behavior yet. So, as I said, do not use this method until you have lured each new behavior as shown in the video.

This is the order in which you should teach behaviors: Lure using a high value treat as shown in the video. After a few successful food lures, lure with an empty hand. If the pup is successful with the empty hand lure, reward with lots of treats. If the pup is unsuccessful, then go back to food-luring a couple more times. After a few successful empty-hand lures, you can begin to add the cue. Say “sit”, then lure with an empty hand, and then reward. Once your pup understands the cue, begin to work on the no-reward marker.

Q. How do I get my dog to stop chewing on things? I kennel her when I leave for a few hours, but I can’t go to the mailbox without her eating something.
ANSWER : A. If she’s young, then this is just normal puppy behavior. Don’t worry about it. The thing about puppies is, they explore using their mouths. If your puppy grabs a coat hanger, or a slipper, you should roll up a newspaper, and smack yourself on the head with it for leaving those things out.. your puppy is going to explore things, that’s normal! It is 100% up to YOU to keep those things away from your puppy when your puppy is unsupervised… even for just a moment.

Remember to never scold your puppy for grabbing these things. They are just curious little cuties, and they don’t chew things up to bother us.. Dogs do not have intentional thought, so they aren’t ever doing anything ON PURPOSE to us.. The most important thing you can do when your puppy is chewing something you don’t want her to be chewing is TRADE her the inappropriate item with a toy of hers, so she understands “no honey, that isn’t what puppies chew on… THIS is what puppies chew on!” and then begin playing with her using her toy to show her that TOYS ARE FUN.. Way more fun than a boring ol’ coat hanger.

Another helpful thing you can do is have two bags of toys. In each bag is many different kinds of toys. Lots of chew toys, lots of soft squeaky toys, lots of rope-type toys, a bunch of balls.. All kinds of things! For one week you have bag#1’s toys out for your puppy to play with.. At the end of the one week, you collect those toys, and you bring out bag#2! The toys will be more interesting/feel like new to your puppy, which will in-turn, make her chew less inappropriate things. Her toys are too fun to care about that dumb Wii-mote that you left laying around.

Hope this helps!

Q. We just adopted a Lab puppy who seems to be hungry all the time. She is usually awake by 4:30 am. Wondering on when and how much to feed her?
ANSWER : A. It depends on the food you feed her. Read the back of the bag of food, whatever it says on the back under “amount for puppy”, decrease that by a very small amount. Often kibble bags encourage overeating to sell more product.

You should be feeding the puppy at three set times throughout the day. A nice and early breakfast, lunch, and dinner. Make sure you aren’t feeding too close to bedtime. Give the puppy an hour after eating before bed in case she has to eliminate outdoors again before bed.

I’m wondering if maybe she’s just waking up at 4:30am to be taken outside to eliminate. Puppies can typically only hold their bladders 1 hour per month of age, plus 1.. and that’s typically pushing it until after 6mo of age. Have you tried just bringing the puppy outdoors, and then luring her back into her crate with a high value treat? See if she’ll go back to sleep.

Q. How can I keep my 14 year old Yorkie from snapping at the younger ones?
ANSWER : A. It’s all about management. Do not allow the 7yo’s to interact with your 14yo unsupervised. You should be there each time they interact so you can redirect the 14yo’s attention onto some toys, or onto some treats when the 7yo’s are around. It sounds like you need to help your 14yo make positive associations with being around the younger pups. You should be trying to feed him treats each time he interacts with them, and doesn’t snap at them. Pet and praise him each time he is around them, or any time they are near. As I said, keep the separated when you cannot supervise their interactions because if you aren’t around when he is snapping at them, you could end up with a fight on your hands.

It could also be that they spend too much time together. Imagine spending 100% of your time with somebody, day in and out, doing everything together… including going to the bathroom.. that might bother anybody. I think you should give them more time apart from each other. Take them all on separate walks, separate them to play with them individually, separate them when you take them to potty, separate feeding times in separate rooms, etc. This can help alleviate the stress your older dog is feeling due to living closely with other dogs. You should always be giving individual activities in a houseful of dogs anyway.. when you expect them to get along 100% of the time, that’s when you find trouble.

Q. My puppy is urinating a lot. And the lady I gave one of the puppies to said she thinks her puppy has diabetes could my puppy have it to
ANSWER : A. It is not likely that either one of these puppies has diabetes. It is very uncommon for a puppy that young to have diabetes. If your puppy is straining to urinate or is urinating very small amounts frequently and cannot seem to wait for very long between urination, he may have a urinary tract infection. It is quite possible that your puppy is completely normal. I would suggest an exam with your veterinarian and discuss the behavior with them. They may suggest a urinalysis. Your puppy should be going to the vet at 3 week intervals for vaccinations at this age, so you can discuss it when he has his next set of vaccines. The other person with the other puppy should also be taking hers to a vet for proper immunizations and she should also discuss her concerns with her vet.

Q. How long should I feed puppy food to my puppy?
ANSWER : A. A puppy should be given puppy food from around the time that the mother begins weaning her pups until the puppy reaches about the age of one year. This is generally true for all dogs, unless your veterinarian has concerns about your puppy’s growth. Under those circumstances, your veterinarian will make alternate recommendations for your puppy’s diet. Otherwise, around one year, you may begin giving your puppy an adult formula dog food at meal times.

Read Full Q/A … : What should you feed a puppy?

Q. My dog should have had her puppies by now. It doesn’t appear to be a false pregnancy to me, however I can’t really tell. Any tips?
ANSWER : A. The standard length of a pregnancy in dogs is about 60-63 days post-breeding. If your dog is nearing that date, it could be that she is having a gestation that is longer than normal. Dogs that are first time mothers can commonly have a longer pregnancy, which may shorten as they have more litters. Signs of an immanent labor include an increase in nesting behavior, discomfort such as pacing or laying funny, “waxing” of the nipples where a waxy pre-milk substance (called colostrum and important in puppy immune function) appearing, or visible contractions rippling along the side of the abdomen (more visible in short-haired dogs).

If you are concerned about the puppies being stuck or the wrong size, you can have your local vet take an X-ray of your female. This is typically done by vets involved in breeding (called theriogenologists) and is used to determine how big the puppies are and how many to expect. Knowing this information is great for making sure there are not puppies stuck in the birth canal, and for knowing if they are premature or not. The X-ray may also show if no puppies are present, which can confirm a phantom pregnancy.

Q. Have a dachshund who is over weight but this past couple of days she refuses to go up steps and her left back leg is not being used, and she is guntin
ANSWER : A. This particular breed is very susceptible to back problems. Your dog is showing some classic symptoms of back pain- reluctance to climb stairs, weakness or inability to use a rear leg and grunting. Your dog should be examined and have radiographs of her back as soon as possible. Hopefully, she can be treated medically, but sometimes back problems progress quickly to something surgical. The quicker you get an accurate assessment of the extent of her problem, the quicker you dan get her some pain relief.

Read Full Q/A … : Theories of gravitation