Optimal puppy growth for a healthy start in life

Introduction

In the first hour of life, once a puppy can breathe and move freely, the predominant instinctual drive is to seek nutrition and fluids. The puppy should quickly locate its mother, find a teat and begin suckling maternal milk (colostrum in the first 24-36 hours) (Figure 1). From birth onwards, the chances of survival, the ability to grow optimally, and the puppy’s general health will rely heavily upon the nutrition received. For this reason, ensuring puppies can obtain optimal nutrition throughout their growth phase is essential for long-term health, whilst inappropriate growth can have lifelong detrimental effects. Veterinary nurses and technicians play a crucial role in ensuring optimal puppy growth by providing guidance, support, and education to the owners, as well as being an excellent source of information should concerns arise (Figure 2).

Growth stages

Puppy growth is rapid but not linear throughout their development period. During the first few months of life, the growth rate is at its greatest, but this slows later on, and reaches completion at the point of skeletal maturity. The duration of growth is determined firstly by breed size category (Table 1), but also as a result of specific breed and individual variables, including the puppy’s gender.

 

Table 1. Broad duration of growth depending on breed size.

 

Neonates

Neonates receive all essential nutrients and hydration exclusively from their maternal milk. In addition, the colostrum contains immunoglobulins, delivering immune protection against pathogens to which the mother has developed acquired immunity. Unlike human babies, who receive 80% of their initial immunity during pregnancy via the placenta, 80-90% of canine maternal immunity is passed to puppies via the colostrum in the first 36 hours of life (1), emphasizing the fact that consumption of sufficient colostrum is vital for health and survival.

Although maternal immunity starts to wane at approximately 4 weeks of age, most (if not all) puppy vaccination programs commence some weeks beyond this point to avoid the likelihood of the maternal antibodies preventing an effective vaccine response.

The first 36 hours of life are critical to survival, as pre-weaning mortality in puppies can be 12-15% (2). Both environmental factors and nutrition play a key role in prevention of these pre-weaning deaths. To ensure puppies are growing correctly in this initial stage, daily weighing should be undertaken, with the expectation that bodyweight increases proportionally (Table 2). Breeders should be advised to seek veterinary assistance promptly should the weight gain be less than expected, even during a single 24-hour period. Closer monitoring of such puppies – and supplementary feeding with milk replacement products – may be required.

 

Table 2. Weight gain expected in puppies per day, depending on age (3).

 

During the first few weeks of life (0-4 weeks), significant quantities of fats and proteins are needed, alongside essential nutrients such as calcium, to facilitate skeletal and other tissue development. The maternal milk adapts to the requirements of the puppy, varying according to age and ensuring perfectly proportioned nutrition.

Weaning

Maternal milk fulfils every nutritional requirement for nutrients and hydration until weaning starts at 3-4 weeks of age. Following the neonatal and early growth phases, puppies gain independence from their mother and their source of nutrition changes (Table 3); with each new phase, the choice, type and consistency of the diet should be considered as well as frequency of feeding and quantity fed. The aim of weaning is to introduce puppies to solid foods and teach them prehension techniques. The ideal diet for weaning is one which has been formulated for this purpose, and contains all essential nutrients, but additionally it is ideal if it can be softened with added liquid to form a porridge-like consistency. Puppies will often lap this food initially but, over a few days, the additional liquid content can be slowly reduced as the puppy learns how to pick up drier foods from a plate or bowl. By 6 weeks of age, provided that puppies have been gradually exposed to drier food consistencies, they should be able to consume dry kibbled diets appropriate to their size. Although weaning is typically completed by 4 weeks of age, many mothers will allow their puppies to continue to suckle for longer, often until they are rehomed at around 8 weeks of age. This should be encouraged, because close proximity to the mother continues to teach essential life skills. Behavioral independence is also not completed until approximately 8 weeks of age, and therefore puppies should not be removed from their mother too early.

 

Table 3. Source of nutrition depending on the age of the puppy.

 

New homes

Once puppies are independent of their mother, nutritionally and behaviorally, they can be rehomed. This is a challenging time for them, both emotionally and physically, so efforts to prevent digestive disturbances should be made. This can be achieved by sending each puppy to their new home with a small quantity of the diet they are currently consuming. To avoid digestive disturbances, new owners should avoid giving too many treats in the first few days and can be encouraged to either continue with the diet the puppy is eating or gradually transition from their current food to the new one, over approximately 3-4 days.

Over the coming months the puppy will continue to grow until it reaches skeletal maturity; to ensure all required nutrients continue to be provided in the correct quantities, diets formulated for growth must be fed throughout this time. As previously mentioned, the rate of growth from birth to adulthood is not linear, and frequent weighing to monitor the growth and careful adjustments to the feeding quantity are necessary to ensure optimal growth is achieved. Therefore, throughout the growth period dynamic, adaptive nutritional recommendations will be central to optimal development and good health.

Young adults

At skeletal maturity the newly adult dog can be transitioned to an adult maintenance diet, aimed at maintaining a healthy weight. Additional nutrient requirements seen during the growth phase have now ceased, and as a result failure to make this switch in diet might lead to over-consumption which, if not corrected, will result in weight gain and subsequent obesity. Conversely, changing to an adult maintenance diet before skeletal maturity may deprive a growing puppy of essential nutrients and energy. Therefore, providing education to pet owners about the need for correct timing of such diet changes is important.

Large breed adaptations

Uniquely in the animal kingdom, dogs as a species exhibit huge size variation. Compared with smaller breeds, large and giant breeds have an extended growth phase, and dogs from these breeds should not, therefore, be prematurely transitioned to an adult diet, and a suitable growth diet must be fed until skeletal maturity is achieved. Given that adult diets are not appropriately nutritionally balanced for growing puppies, transitioning a large breed puppy prematurely can result in imbalances in nutrient intake, particularly excessive calcium intake, which increases the risk of orthopedic diseases. Beyond feeding an inappropriate food as the main meal, calcium should never be supplemented. There are also risks resulting from puppy owners trying to promote maximal growth in a large or giant breed puppy, believing that “bigger is better”. This can result in artificially accelerated growth, which as well as predisposing to obesity, can prejudice the developmental orthopedic diseases, such as hypertrophic osteodystrophy, osteochondrosis (OCD) and hip dysplasia. Indeed, given that 20% of orthopedic disorders in adult dogs are linked to dietary factors (4), puppies from large and giant breeds should only be fed a diet formulated for growth, but ideally the diet should also take into account the specific nutritional requirements for an extended growth duration.

Ensuring that growth is optimal

Many suitable complete and balanced propriety diets can support growth in puppies as they contain an appropriate balance of proteins, vitamins, minerals and fatty acids relative to their energy content. It is a legal requirement that each food package provide information on how much a pet owner should feed their puppy, usually in the form of a feeding guide. However, when examined in detail, such feeding guides provide only broad ranges of portion size, making it difficult to determine an appropriate amount for an individual puppy, and how to make adjustments should growth not progress optimally. Veterinary nurses and technicians are perfectly placed to provide help and advice for owners here, not least if they recommend the use of an evidence-based growth chart (Chart 1), a tool which has recently become freely available (for both puppies (5) and kittens (6)) for monitoring development and making necessary adjustments.

When using a growth chart, it is fundamental that the correct chart is selected. A range of different sizes of growth chart for puppies are available (Table 4) designed for both males and females for each size category. These reflect the differences in how puppies in the different breed size categories grow, as well as size differences due to gender. Where the expected adult weight is unknown (e.g., for many mixed-breed dogs), an approximate adult size can often be guessed (based on the likely breed make-up), meaning that the chart choice can be narrowed to one of two charts. Initial weights can then be plotted on both charts and, over time (also with reference to clinical variables), the correct chart usually becomes apparent. If in doubt, the chart where the growth is following one of the middle centiles should be chosen.

 

Table 4. Available puppy growth charts, categorised by expected adult weight and
typical breeds for which each chart size is suitable.

 

To start using a growth chart, the puppy’s date of birth and current bodyweight in kilograms will be needed. Puppies should be weighed (on calibrated scales) without harnesses, collars or leads, and the date of birth used to calculate the age of the puppy in weeks (Figure 3). Smart phone applications can make this calculation quick and easy.

Once the typical growth pattern for a puppy is established, by using multiple plotted points, the correct centile for that individual can be determined. This centile can then be tracked forwards (to where the curve flattens) and used to provide the owner with an expected adult weight, which can also be used to verify the correct feeding quantity.

Given that within a given category, different breeds (as well as individuals within breeds) can vary somewhat in size, no single centile is necessarily correct or ideal; put another way, the correct centile line for any puppy is the one it follows whilst growing at a healthy weight. Each centile demonstrates an initial period of rapid growth, which then slows as the puppy nears skeletal maturity. Since growth charts depict optimal growth, they can also be used to identify deviations from this “normal”, prompting the veterinary professional to take action to address the cause. This means that owners can be given sound nutritional recommendations, tailored to their puppy, as well as providing reassurance that their pet is growing correctly. Both printable and online versions of the charts are available to suit the preference of each owner. Although the online tool provides some automated flags when there might be deviations from expected growth, owners should still be encouraged to contact their veterinary practice for confirmation and specific advice, with veterinary nurses being perfectly placed to deliver such guidance.

For the growth charts to be an effective tool, multiple weights must be plotted before the growth pattern can be observed. The minimum weighing frequency is once per month until six months of age, and then every three months thereafter. However, more frequent weighing, even once per week, can often enable even finer tuning towards the optimal individual growth pattern.

Growth patterns of concern

Beyond encouraging weight monitoring and demonstrating ideal growth based on the plotted growth points, growth charts additionally allow for growth patterns of concern to be identified, facilitating reviews of feeding and even occasionally diagnostic investigations to determine the cause.

Risk of obesity in adulthood

A growth pattern which deviates upwards, crossing centile lines (especially two or more) can be a predictor for a risk of obesity in adulthood (5) (Chart 2). By identifying such risks early – simply by monitoring growth patterns – rapid corrective action can be taken, with the hope that this will prevent obesity and its clinical consequences. Obesity in dogs is highly prevalent and increasing in frequency, with 65% of dogs in the UK (7) and up to 63% in the USA (8) found to have an increased body condition associated with excess weight or obesity. Given the clinical consequences of obesity, including direct impacts (9), increased risk of obesity-associated diseases (9), shorter lifespans (10) and poorer quality of life (11), such growth monitoring is vital.

Failure to thrive

Action should be taken if any puppy appears to stop growing or significantly slows in its weight gain. This can be observed on the growth chart by a flattened line, with the growth trajectory crossing centile lines downwards (Chart 3). In this instance, a clinical review should be conducted, considering possible illness and changes to diet or activity level; corrective measures can then be implemented, along with closer monitoring, with the aim of the puppy recovering its normal growth pattern.

Rapid “catch-up” growth

All puppy owners wish to see their pet grow and thrive, but it can be difficult for owners not to compare their puppy to others, including those from the same litter (Figure 4). As such, when a puppy has a smaller stature, but is growing along one of the lower centiles, the owner may try to accelerate weight gain, so that their puppy ‘catches up’ with others (Chart 4). However, this practice should be discouraged, not least because inappropriately rapid growth can have health consequences (see above). Therefore, every owner should be reassured that whichever centile line their puppy is following is the right one for them, provided they are healthy.

Large for age

Each growth chart has centile lines with a numerical label; these represent the proportion of the population that is lighter than that weight at any given age. So for example, a puppy growing along the 99.6^th centile is unusual, since this represents only 0.4% of the population (Chart 5). This may well be a normal growth pattern for the puppy in question; however, being very large for age is also associated with a greater risk of obesity in adulthood, even if centile lines are not crossed (although, not uncommonly, both occur together). Therefore, owners of larger puppies should be encouraged to weigh them more frequently, and adjust the food intake as appropriate.

Dynamic nutritional recommendations

Such is the accuracy with which growth can be followed using the growth charts that feeding quantities can be finely adjusted as necessary. Owners can be reassured that, provided their puppy’s growth is consistent with their growth chart, the amount of food they are giving at that moment is appropriate. As the puppy grows, small adjustments to the feeding quantity can be made to ensure the puppy continues to follow their centile line; of course, frequent visits to the veterinary practice are recommended, since this is the best way of facilitating this approach. Feeding of treats should be limited (ideally to <5% of the daily caloric intake), so as to ensure that the diet does not become unbalanced. Where deviations are seen, provided that they are only minor, recommendations can then be made to get the growth back on track, either by increasing or decreasing food intake. Finally, growth charts also indicate the approximate point when skeletal maturity is reached, facilitating transition to an adult maintenance diet.

Conclusion

The health of puppies from the moment of birth relies heavily upon their nutrition. The growth phase is a time of change, and therefore nutritional recommendations must reflect the evolving needs of the puppy. Evidence-based puppy growth charts are now an essential tool in facilitating this for appropriate nutrition and development. By plotting the puppy’s growth, the risk of developing medical disorders, either during growth or later in life, can hopefully be avoided.

 

References

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