The Science

The science behind M.E.G!

If you are thinking of buying/obtaining a puppy then essentially there are two areas you need to check out very carefully: they are the puppy’s genetic and environmental background. These two areas can be looked at in more detail if examined in relation to the effects they can have on a puppy before and after it is born. Essentially, a breeder will influence the future physical and mental development of a puppy; this can be a negative or positive influence.

Before the puppy is born:

A good breeder will only breed from a temperamentally sound Mum (and Dad) as nervousness or fearfulness can certainly be genetically inherited by being passed directly in the DNA from parent to off-spring (Dykaman et al, 1979, Murphree, 1973 and Dykaman at al, 1966). As you can see from the dates of these references this knowledge has been around for almost 50 years!

While greater emphasis is generally placed on Mum, it should be apparent that a puppy’s Dad will also have a behavioural contribution to make.

The take home message is: A canine Mum and/or Dad that is nervous, reckless or aggressive can pass these genetic traits unto their off spring. If the male is used as a stud dog then his genes could be far reaching. If either parent shows fear, anxiety or aggression then as a prospective dog owner you should ask yourself if you want to take on a puppy that may also have these traits (Ryan, 2013). Some puppies at 7-8 weeks of age may already be displaying nervous behaviour.

In addition, a reputable breeder will only breed from parents that have been tested for serious health conditions that are known to be passed genetically to their offspring. Some of the most common tests are: Hip and Elbow Dysplasia Scheme, Eye Screening and DNA tests for specific conditions in some breeds. See more at:

Now let’s examine the breeding environment: the first environmental factor that will determine a puppy’s temperament is whether it’s Mum is raised in a happy home.

Puppies prior to birth are suspended in a ‘hormonal soup’ in the womb. If a canine Mum is stressed, high levels of distress hormones (cortisol and adrenaline) will circulate through the placenta from Mum to her unborn puppies. Prenatal exposure to these hormones can lead to anxiety, fear and even aggression problems after birth (Horwitz et al, 2015). This is one of the reasons that puppy farms are one of the worst disservices we’ve ever done for dogs (Ryan, 2013).

There is another branch of science that looks at how the environment can influence the genes of animals. This branch is referred to as epigenetic inheritance. This process of inheritance occurs when various enzymes are released and affect the outside of the chromosome; that then affect how the gene within act. Unlike the DNA sequence (see Genetics above), epigenetic processes are not fixed and are strongly influenced by the environment and by exposure to external factors such as diet, living conditions, exercise, stress, chemicals, drugs and toxins. The influence can be positive and negative. For instance, positive factors such as good nutrition and enriched living conditions, can promote beneficial characteristics in an animal, whilst poor diet, chronic stress and traumatic events can promote damaging characteristics.

In other words, experiences and environmental exposures could change the way an animal’s DNA works (without changing the DNA within the gene itself) and this could be passed on to their offspring and amazingly offspring across several generations via sperm and eggs. Hence, what happens to a canine Mum during her lifetime may have consequences in future generations.

The take home message is: That a canine Mum needs to be in the centre of a loving family, not subject to undue stress or distress. Breeding from distressed mothers perpetuates the problem.

After the puppy is born:

Designing a good environment for the development of a puppy depends upon knowledge of the periods of development. In the neonatal period (0-3 weeks) the breeder should be concentrating on making sure that the Mum is well nourished and provided with adequate comfort and quietness to care for her puppies without undue stress.

During the transitional /early socialisation period (3-5 weeks of age) it used to be thought that little environmental enrichment input needed to done. However, it is now known that during this 3-5 week period puppies are at an optimum stage of development to experience things that they will be expected to deal with in the future as a pet dog (Appleby and Pluijmakers, 2004). Building up a solid set of positive experiences for a puppy at this stage is one of the biggest favours a breeder can do for them. Gently fading in a wide range of sights, sounds, smells, taste and touches so that the puppy thinks of them as normal is a great start.

When a pup enters the next stage, often referred to as the socialisation period (5- 12 weeks of age), more care needs to be taken especially in weeks 5-8 as they can now become frightened more easily, so a breeder needs to make sure introduction to new things are not done in a scary way. Unscrupulous breeders can evoke fear in puppies by removing them from their Mum too early and/or transporting them around the country (or from one country to another) with little thought to their physical and mental wellbeing. Fear is the biggest source of threat for a dog and threat the biggest source of aggression. Reduce the fear in the pup and you reduce the chances of biting and fighting in the adult dog (Ryan, 2013).

The take home message is: 3-8 weeks of age is a crucial time for a puppy to have positive experiences and the breeder has the ultimate responsibility for this period of your puppy’s life.

In addition to all of the previous discussion, consideration must also be given to what the pups are learning from their Mum’s behaviour (Ryan, 2013). If a Mum is showing fear or aggression towards people then there is every chance that her pups will too. The lesson she is teaching them every time a new person appears is that they should be feared or ‘It’s Ok to be aggressive to people’ – not a great start in life!

The take home message is: Mum will influence how her puppies perceive people either in a good or bad way. Mum should be happy to see you and come out wagging her tail with happy puppies following.

After you have got your puppy:

While a huge amount of emphasis had been placed on an ethical and knowledgeable breeder providing a puppy with the best start in life, it doesn’t mean that you as the new puppy owner doesn’t continue the process! For indeed you must; not just for a few days or weeks but forever. Socialisation doesn’t end at 12-14 weeks of age; it really doesn’t end at all. Dogs are susceptible to developing fears of novel stimuli at any time during their life, so they need to be introduced to them sensitively at any age. That is why starting out well is important, as it will allow a puppy to face life’s challenges, but continuing is also necessary (Ryan, 2013).

Please Think M.E.G


D Appleby and J Pluijmakers (2004), chpt. 2 in The APBC Book Of Companion Animal Behaviour, 2004, ed D Appleby, Souvenir Press.

Dykman RA, Murphree OD, Ackerman PT: Litter patterns in the offspring of nervous and stable dogs: II. Autonomic and motor conditioning. J Nerv Ment Dis 1966, 141(4):419–432.

Dykman RA, Murphree OD, Reese WG: Familial anthropophobia in pointer dogs? Arch Gen Psychiatry 1979, 36(9):988–993. 10.1001/archpsyc.1979.01780090074008

Horwitz D, Ciribassi J and Dale S (2015), chpt 2 in Decoding Your Dog, Mariner.

Murphree OD: Inheritance of human avoidance and inactivity in two strains of the pointer dog. Biol Psychiat 1973, 7(1):23–29.

D Ryan (2013), chpt 5 in Dogs that Bite and Fight, 2013,, Ltd.

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