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Jane Lefler
Jane Lefler, Animal Behaviorist
Category: Dog Training
Satisfied Customers: 20217
Experience:  Dog breeder/Trainer and Behaviorist 18+ years
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my 8 year old lab has recently started to become aggressive

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my 8 year old lab has recently started to become aggressive towards myself and family members for no apparent reason. he can be lying down then suddenly hes growling . also if I tell him to do something hes growling but does it anyway .His eyes go dark an glassy just before he starts growling it is frightening but I don't think he would attack anyone at this point I rise above him and make him go out side. it seems to me like something comes over him and after the episode its like nothings happened .what do you think .
Hi JaCustomer,

My name is Jane. I have been working professionally with animals especially dogs in both health and behavioral issues for over 18 years. I have over 14,000 satisfied customers. It will be my pleasure to work with you today.

In order to supply you with the best information, I do need to ask for some additional information. Once I receive your answer, it will likely take me about 30-45 minutes to type up your response. I hope you can be patient.

Is he neutered?
Is he shedding more than he has in the past?
Is he aggressive toward other people as well?
Does he have a hard time rising in the morning?
Does he drink more since this started?
How long has this been happening?
What training aids are you trying to use?
Has he had obedience training?
Has he started having accidents in the house?
Does he ask to go out and then want back in without eliminating or ask to come in and want back out immediately?
Does he seem to bark at people he should know?
Has he ever gotten stuck behind furniture or doors?
Customer: replied 4 years ago.
1. yes. 4. no. 5. no. 6. 3-4 months now. 7.bark buster pads. the past when he was younger. 9. no. 10. no. 11. no. 12 no. hope this helps

Thanks for the additional information. It is helpful. I ask because there are medical issues that can lead to sudden aggression. Pain is one of them and hypothyroidism is another. Labs are prone to several conditions that cause pain such as hip dysplasia and arthritis especially if they are overweight which many older labs are. Hypothyroidism is also prevalent in labradors as well. You can read about these below.

Unfortunately, the site does not allow me to make clickable links, so to view the supporting websites, you will need to copy and paste the link into a new browser window or tab.

Unfortunately, many of these conditions can only be diagnosed with additional testing.

The other thing that often happens with older dogs like yours is that they develop the dog form of Alzheimers (cognitive dysfunction syndrome) or CDS. This can cause aggression as they may not recognize people they should know like the family.

If there have been changes in the household especially the loss of another dog, that might trigger him to become more dominant and feel he can boss the people. If it is strictly behavioral, starting back up obedience training can help reestablish the humans as the boss.

Training works best if you train at least 30 minutes a day (two 15 minute sessions). I would start making your dog work via the Nothing in life is free program (NILF). It is outlined below.

Keep a leash on him and give him a short tug and a firm no when he acts inappropriate. Once you notice him not acting inappropriate when he would have previously, reward the desired behavior with liver slivers or vienna sausage slices. Dogs love these treats. All family members should participate in training for it to be effective.

Have everyone be sure and let the dog know they are walking up on him even if he is asleep. A dog upon waking up can sometimes snap out before seeing who it is.

I definitely want you to have him given a senior check up including bloodwork and a thyroid panel. Make sure the vet checks his eyes and hearing as much as possible as that can cause a dog to act aggressively until they realize who it is.

I do feel it is likely to be medical in nature given the sudden onset and his senior status. I hope this information is helpful to you and you are satisfied with my response. If you would like any additional information or have more questions please don’t hesitate to press the reply to expert or continue conversation button so I can address any issues you still have .
Jane Lefler and other Dog Training Specialists are ready to help you
Customer: replied 4 years ago.
before i contacted you .i took him to the vets to get their opion they gave him a clean bill of health although he is overweight which at the moment ive put him on a diet .but they said they couldnt comment cus it not their field. i will take a look at those links thank you .and i am doing the retraining.
Arthritis and hip dysplasia are conditions they could likely be able to diagnose, but hypothyroidism requires special testing and is a problem in the breed. If they did indeed run a thyroid panel then you can rule that out. If they didn't take x-rays, I would consider having that done if behavior modification through training doesn't do the trick. Be sure they do head, and spinal shots as well though some disc issues require myelogram or ct scans to diagnose. If you need more training tips as you move forward with behavior modification, you can add comments at any time and I'll respond back.