Energy Requirements for Growth in the Yorkshire Terrier

Please note: The following is a summary of a research article, referenced at the end of this page, by Janet E. Alexander, Alison Colyer, and Penelope J. Morris.

 

Puppies need proper nourishment to stay healthy as they grow into adults. This study on Yorkshire terriers, a toy breed, distinguishes breed differences as key factors in determining how much dogs need to be fed. This is significant because improper feeding may explain small and toy breeds’ susceptibility to become obese, which can result in decreased life expectancy.

Earlier studies have shown that different breeds’ growth patterns vary. Their energy requirements are likely affected by the characteristics of each breed (ie. size, coat type, temperament) (Alexander, Colyer, & Morris, 2017). Specifically, the energy requirements of Labrador retrievers and miniature Schnauzers have previously been recorded. The NRC (National Research Council) 2006 puppy energy requirement equation overestimated the needs of miniature Schnauzer puppies, while initially overestimating and then underestimating those of Labrador retrievers (Alexander et al., 2017). This study documented the energy requirements of the Yorkshire terrier and compared them to predicted values from the NRC 2006 equation, as well as that of medium and large breeds (Alexander et al., 2017).

The experiment used 22 Yorkshire terrier puppies from 8 litters that were raised in a controlled environment (Alexander et al., 2017). They received socialization, training sessions, and access to the outdoors (Alexander et al., 2017). No subjects had skeletal abnormalities (Alexander et al., 2017). At 3, 6, 9, and 12 months of age, the puppies’ blood samples were tested to confirm that they were within the expected biochemistry and haematology parameters (Alexander et al., 2017). During the test, they were fed wet, dry, or a mixture of both foods (Alexander et al., 2017). The feeding allowances were adjusted each week according to the WALTHAM S.H.A.P.E. (Size, Health and Physical Evaluation) guide to maintain ideal body condition score during the study (Alexander et al., 2017). (The guide uses physical and visual characteristics to estimate fat content.) The puppies aged 10 to 26 weeks old were fed daily in 3 meals lasting 30 minutes each (Alexander et al., 2017). When the puppies were aged 27 to 52 weeks, they were fed 2 meals lasting 30 minutes each (Alexander et al., 2017). Then, their diets were analyzed so that the energy intake could be calculated. Separately, the predicted energy requirements based off of the NRC 2006 puppy energy requirement equation were calculated using the adult body weight of the subjects at 52-weeks old (Alexander et al., 2017). Thus, the actual energy intake values could be compared to the predicted values, as well as those of Labradors and miniature Schnauzers.

The results show that the NRC 2006 equation overestimated the energy intake of Yorkshire terriers from the ages 10 to 20 weeks and produced comparable values from ages 21 to 52 weeks, except for weeks 25 and 45 (Alexander et al., 2017). Although the discrepancy in week 25 might caused by the neutering of the subjects, the difference in week 45 has no explanation (Alexander et al., 2017). Furthermore, or puppies from 10 to 29 weeks of age, the energy intake of Yorkshire terriers was significantly lower compared to Labrador retrievers (Alexander et al., 2017). On the other hand, although miniature Schnauzers and Yorkshire terriers from week 10 to week 15 had the same observed energy requirement, from weeks 16 to 23 and in week 25, the Yorkshire terrier’s values were significantly lower (Alexander et al., 2017). After 29 weeks, breed had little effect on energy requirement values (Alexander et al., 2017).

The data uphold that energy requirement during a growth period is closely related to breed size and age (Alexander et al., 2017). Therefore, these breed characteristics are a factor in determining feeding amounts, which is not taken into account by the NRC equation (Alexander et al., 2017). This problematic NRC equation can lead to excessive feeding and weight gain of Yorkshire puppies (or puppies of similar size). More research needs to be done for breed-specific feeding guides, and a potential future study could use accelerometry to relate how active puppies of different breeds are with their energy requirements (Alexander et al., 2017).

 

Reviewed by: Sofia Hsu, 10/27/18

References:
 
 
Alexander, Janet E et al. “Energy requirements for growth in the Yorkshire terrier” Journal of nutritional science vol. 6 e26. 24 May. 2017, doi:10.1017/jns.2017.26