Just like human athletes, canine athletes need specialist nutrition, supported by appropriate training to perform at their very best. When considering the active dog, it is easy to think of the extremes, the Greyhound and endurance racing Husky, from which much information on canine nutritional requirements for activity have been generated. Practically, this does bring challenges to dietary design and the need for appropriate interpretation, as the range of activities that dogs participate in is varied; for example, dogs retrieving game in the hunting field, farm herding dogs, military dogs, mountain search and rescue dogs and those taking part in events such as agility.
Physical attributes accredited to the wellbeing of our furry companions, such as good energy levels, a strong immune system, strong muscles, appropriate body condition score, flexible joints, sharp vision and optimal mental alertness, are accentuated in an active dog. Furthermore, DSM’s pet parent survey data clearly indicates that pet parents associate living an active life with good health and that pet foods and treats positioned to support an active lifestyle hold strong appeal.
Energy requirements do spring to the forefront of one’s mind in diet design for active dogs. It is however also important to consider the specific role of each dietary nutrient for the active dog, including water and some nutraceuticals, and under what circumstances a change in supply above maintenance levels or supplementation maybe appropriate. Not all nutrients will change in proportion to energy intake per se. Maintaining an appropriately balanced diet of all nutrients is vital to success (FEDIAF, 2018).
Vitamins and Carotenoids
Vitamins are involved with all metabolic reactions in the body. Achieving Optimum Vitamin Nutrition (OVN®) helps ensure that a dog’s food provides adequate amounts of all essential vitamins needed for an active life. The B vitamins for example, play a vital role in normal energy metabolism. Vitamin A is required for strong vision, an essential for an active dog. Optimizing dietary biotin content with appropriate amounts of dietary zinc and essential fatty acids will help ensure that dogs have good skin, paw and coat quality.
During exercise, production of reactive oxygen species and other free radicals can increase. If they do so above the capability of the dog’s antioxidant system, it results in the condition of oxidative stress (Hinchcliff et al, 1998). In sled dogs, those with higher levels of plasma vitamin E were found more likely to finish a race (Hinchcliff, et al, 2000). In addition, immune system function has been demonstrated to be altered by exercise. Providing intensely exercised sled dogs with 21.7 mg beta-carotene, 18.4 mg lutein (both carotenoids with antioxidant properties), and with 400 iu of vitamin E was shown to normalize their immune system response (Chew, 2000).
Vitamin C has been the subject of much debate and excessive supplementation is questionable. Nevertheless, as a part of an antioxidant package, and its role in vitamin E recycling, some degree of supplementation would seem sensible. Such an antioxidant package would also include, particularly in higher fat diets, vitamin E to provide at least 200-400mg daily to the average sized dog, along with supplemental beta-carotene. Beta-carotene at an inclusion rate to provide 30 mg/kg in dietary DM (4000 kcal) at point of consumption is suggested.
Carnitine and Taurine
Carnitine has an important role to play in beta-oxidation of fatty acids and energy metabolism in muscle and heart cells. Although produced by the body, additional dietary carnitine may have a supportive role to play in the nutrition of active dogs (Grandjean D., et al. 1993, 1977). Carnitine together with taurine have roles to play as antioxidants and in the support of the cardiovascular system (Siktar et al, 2001; Roudeboush and Keen,2010; Jong et al, 2013, Ra et al, 2016).
Dietary Fat and Essential Fatty Acids
Fat utilization to provide energy always dominates in dog muscle, except the first few seconds of a sprint, though clearly at close to maximal oxygen consumption glucose plays its part. Fat reserves are greater than those of glycogen and help to sustain the dog’s endurance. A suitable guide is to provide between 13-15% of calories from fat in maintenance diets increasing as the duration of activity is extended, to 50% or more for endurance. Training a dog undertaking endurance activity on a diet with proportionally more calories from fat increases mitochondrial mass and number, enhances VO2 max, the maximum amount of oxygen that an individual can utilize during intense or maximal exercise and enhance stamina by improving aerobic metabolism (Reynolds 1996). The dog will consequently run further for longer.
In terms of the fatty acid profile, diets rich in polyunsaturated dietary fatty acids may beneficially affect the scenting ability of trained active dogs (Altom et al 2003, Angle et al 2014). The long chain omega 3 fatty acids have a role to play in reducing inflammatory responses. In addition to its role in management of inflammation, the fatty acid omega 3 DHA has a role to play in the function and structure of the retina in the eye, plus the neural system and brain.
How Much Protein?
Adequate protein supply is important to help maintain muscle mass and integrity, as well as blood albumin, hematocrit and the immune system. Contrary to popular opinion, it is much less important as an energy source. It is suggested that around 24% of dietary energy from protein is ideal for sprint dogs, with some good evidence to suggest that excess protein intake can reduce sprint performance (Hill et al 2001). For endurance dogs however, more than 30% of dietary energy should come from high quality protein. Studies do indicate that plant-based proteins do not support the canine athlete as effectively as animal sources (Wakshlag et al 2003, Middlebos et al 2009). However, these results may be entirely due to an inappropriate amino acid profile rather than the protein source per se (Fiacco et al, 2017).
Carbohydrates for Active Dogs?
Carbohydrate (CHO) inclusion in the diet requires careful consideration. Excess dietary fiber is a diluent to energy content, adds weight to the gastrointestinal tract, influences fecal bulk and defecation frequency which may all adversely affect the activity and reduce competitive speed. However, some functional carbohydrates, such as short chain FOS (fructo-oligosaccharides), XOS (xylo-oligo-saccharides) or MOS (mannan-oligosaccharides), are reported to help support a healthy gut flora balance and immune system (Swanson et al 2002). Some degree of water retention through dietary fiber may however help to maintain osmotic balance in the dog.
Readily available sources of starch and sugars nevertheless provide a good energy resource for the sprint athlete, providing 35-50% of the energy needs. Whereas for endurance, it is recommended to reduce this supply to ~10%. It may be more helpful if this smaller contribution also provides fermentable CHO to help support gut function and reduce the incidence of stress related diarrhea.
The energy demands of the active dog are directly related to the terrain, and distance travelled both horizontally and vertically (NRC, 2006). Table 1 provides a guide to the daily energy requirements (DER) for dogs at various levels of activity. Individual energy requirements of dogs do however vary, and they should be fed accordingly to maintain the level of performance required and ideal body condition score.
Climate has less of an effect on energy needs but is worth noting that hot weather can be as demanding on the dog’s energy expenditure as cold. With each degree of temperature above or below the thermo-neutral zone for the dog accounting for an additional 3-5 kcal.kg bodyweight -0.75.°C-1. For most dogs this zone is between 20-30°C (NRC, 2006) although for Huskies it is estimated that their lower critical temperature is 0°C or less. Windchill, fur condition, fur density and immersion in water will also affect the dog’s response to environmental temperature.
The intensity and, or speed of the dog’s activity affects where the energy it requires comes from. Although active dogs need to consume energy sources each day, they do not directly utilize the energy from the food they ate that day to drive the performance, but inbuilt reserves, such as fat stores, muscle and liver glycogen. Therefore, feeding the active dog is all about developing those reserves effectively through an appropriate diet over time, and adapting, through training, the biochemistry of the dog to utilize the stored energy efficiently.
Feeding Program to Better Support Energy Levels
Timing of feeding affects how dogs utilize dietary energy sources. Some studies indicated that feed restriction prior and during an event improved performance and carbohydrate re-supply immediately following an activity can help restore muscle glycogen for sprint events (Wakshlag, 2013). For dogs running hard, repeatedly on successive days of between 5 mins and 4 hours there may be benefits to each subsequent performance event from feeding 1.5g of maltodextrin or similar carbohydrate per kg of body weight within 30 mins of completing the exercise. This will help to replenish muscle glycogen; such a strategy should be before feeding the normal diet (Reynolds et al, 1997, Wakshlag et al, 2002, Clero, et al, 2015). In practical terms for the pet food manufacturer, development of a specially designed feeding program for a food or treat around an event type, could give manufacturers another tool to differentiate their product.
Older Active Dogs
When it comes to the older canine athlete the same feeding rules apply dependent upon the nature of the event. However additional support for joints from omega 3 fatty acids such as DHA (230-370mg/kg BW 0.75 EPA&DHA) (Bauer, 2011), and other chondro-protective agents such as glucosamine and chondroitin may be helpful. Further, it is important that the working dogs’ mental agility is maintained. DHAgold, an alga, naturally rich in DHA, has been shown to provide significant learning and visual processing benefits in senior dogs (Hadley et al, 2017).
Correct protein and amino acid intake must be maintained in the older dog to maintain muscle mass. As protein turnover almost doubles in older verses younger adult dogs, and assuming such older athletes are not overweight, then high proportions of ME (metabolizable energy) from fat and protein are desirable in senior working dogs. Older active dogs may also benefit from enhanced intake of dietary antioxidants such as beta-carotene to overcome age related immune function decline (Massimino et al, 2003).
Water is often the forgotten nutrient, yet it is vital to optimizing the dog’s performance. The requirement for water increases in direct line with energy requirement and in hot weather may double. Higher protein intakes further increase water requirements with regards to urea excretion. Water should be provided for the dog immediately after the event, whilst electrolytes are contra indicated at this time. They are not lost through sweat, as dogs predominately pant. Studies to date indicate either no benefit to recovery or subsequent performance and, or may increase incidence of diarrhea (Mazin et al 2001, Young et al 1960)
Using consumer data to build products for active dogs
The DSM 2013 DSM Pet Food European Survey found that pet food concepts based on a leading dog food brand (base concept) that promoted activity or supported mobility, an aspect of active living, were highly attractive to pet parents (table 2) and were ranked equally or better than that base brand. A following 2017 survey, demonstrated that pet parents link the pet’s activity level to its happiness (table 3). Although some differences existed between countries, key nutrients are recognized and linked to aspects of the dogs’ physiology or health required for activity. Pet parents also recognize that weight management is a good way to support their dog’s activities levels. Weight management diets positioned with activity, could therefore have the potential to be highly attractive to the pet parent.
Pet parents link activity to good wellbeing and happiness. Products positioned to support activity, or an active life, with recognized nutrients gives pet food manufacturers an additional marketing message to apply to foods, or novel treats appealing to both the more health conscious and “active” dog parent. Active dog diets are not just for the extreme performance dog.