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It has been reported that daily fluid intake influences urinary dilution, and consequently the risk of urolithiasis in human subjects and dogs. The aim of the present study was to investigate the role of dietary moisture on urinary parameters in healthy adult cats by comparing nutritionally standardised diets, varying only in moisture content. A total of six cats were fed a complete dry food (6·3 % moisture) hydrated to 25·4, 53·2 and 73·3 % moisture for 3 weeks in a randomised block cross-over design. Urinary specific gravity (SG), urine volume, water drunk and total fluid intake were measured daily; relative supersaturation (RSS) for calcium oxalate (CaOx) and struvite was calculated using the SUPERSAT computer program. Cats fed the 73·3 % moisture diet produced urine with a significantly lower SG (P,0·001) compared with diets containing 53·2 % moisture or lower. Mean RSS for CaOx was approaching the undersaturated zone (1·14 (SEM 0·21); P ¼ 0·001) for cats fed the diet with 73·3 % moisture and significantly lower than the 6·3 % moisture diet (CaOx RSS 2·29 (SEM 0·21)). The effect of diet on struvite RSS was less clear, with no significant difference between treatment groups. Total fluid intake was significantly increased (P , 0·001) in the 73·3 % moisture diet (144·7 (SEM 5·2) ml, or 30 ml/kg body weight per d) compared with the 6·3 % (103·4 (SEM 5·3) ml), 25·4 % (98·6 (SEM 5·3) ml) and 53·3 % (104·7 (SEM 5·3) ml) moisture diets, despite voluntary water intake decreasing as dietary moisture intake increased. Cats fed the 73·3 % moisture diet had a higher total daily fluid intake resulting in a more dilute urine with a lower risk of CaOx when compared with the lower-moisture diets.The extent to which cats are able to adjust the amount of water they drink in relation to the moisture content of their diet has been a source of investigation over the last 30 years. Cats fed an all meat or wet diet, which typically contains in excess of 75 % moisture, will voluntarily drink only small quantities of water (1,2) . Although cats drink more water when offered dry diets, they do not drink amounts that would be expected to compensate for the significant reduction in moisture content of these diets (2) .It is believed that cats adjust their water intake such that they effectively excrete their renal solute load. Since cats fed dry food have a lower total water intake than when fed wet food, it would suggest that the absolute water requirement to dilute the renal solute load is lower than that resulting from a wet-food diet. This means that cats fed wet or natural diets may consume water in excess of any physiological requirement.Dry cat foods have been implicated as a risk factor for cats susceptible to feline lower urinary tract disease (3) , while feeding wet diets has been shown to reduce the recurrence of calculi and signs of idiopathic cystitis compared with dry food (4) .While the benefits of wet food are thought to be attributed to the increased water intake and related increase in urine volume, additional ...

A meta-analysis was carried out in order to establish the energy requirements of adult cats. Publications that identified cat body weight (BW) were used to generate allometric relationships between energy requirements and BW of healthy adult cats, using log-log linear regression. Energy requirements were expressed in kcal/kg BW to be consistent with those reported by the National Research Council. Mean maintenance energy requirements were 55·1 (SE 1·2) kcal/kg BW (115 treatment groups). Three allometric equations were identified to predict the energy requirements for maintenance of BW in the cat based on BW: light (53·7 kcal/kg BW ). When reported on lean mass, the allometric equation revealed maintenance requirements were 58·4 kcal/kg lean mass 21·140 (adjusted R 2 0·694; thirty-six treatment groups). The present review suggests that values for maintenance energy requirements based on BW alone may not be an accurate prediction and more detailed information on the age, sex and neuter status, BW and composition would enhance the ability to interpret the maintenance energy requirements of cats. Cats: Energy requirements: Allometric equationsWhile the relationships between energy requirements and age (1,2) and body weight (BW) (3) have been determined in domestic cats, these reports utilised the outcomes of a series of studies in only a single colony of cats. Given the increase in obesity levels in companion animals and the number of recent studies that have investigated this phenomenon, meta-analysis may be an appropriate tool to accurately determine the energy requirements of adult cats. The use of meta-analysis is a powerful method by which the results from multiple independent experiments can be combined to produce more robust results than can be obtained from single experiments alone (4) . Combining results from different experiments using statistical meta-analytical methods can reduce the extent that differences in experimental conditions may have an impact on the calculated prediction equations and cause bias. Additionally, meta-analysis can identify factors that may influence these relationships.Maintenance energy requirements for adult cats have been calculated to be 100 kcal/kg BW 20·67 for normal-weight, and 130 kcal/kg BW 20·4 for heavy cats (5) . The National Research Council (NRC) (5) highlighted that the literature reporting maintenance energy requirements in adult cats is highly variable. For example, the effects of age on maintenance energy requirements differ markedly among publications, as does the effects of neutering. These effects may be explained by other factors that were not taken into consideration among studies, such as age of the cat or methodology used to determine the cats' energy requirements.The objective of the present review was to conduct a meta-analysis on the energy requirements for maintaining BW in adult domestic cats in order to (a) determine predicted changes in energy requirements with weight, and (b) account for factors that may influence these relationships. Initial resul...

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Recent evidence in humans has reemphasized the importance of specific lifestyle behaviors such as activity level on energy requirements. A recent survey of adult pet dogs has shown a clear association between the level of activity and energy requirement, and suggests that current feeding recommendations may overestimate the energy requirements of adult dogs. Although a reduction in feeding guides may help to reduce the risk of overfeeding and subsequent development of obesity in adult dogs, there is considerable individual variation in energy requirements, which emphasizes the importance of tailoring feeding practices to the individual. Diet clearly has a critical role to play in both the prevention and treatment of obesity. We have evaluated the effect of different dietary regimens on the treatment of obesity in companion animals. In cats, increased energy restriction results in more rapid weight loss. However, this is associated with less favorable changes in body composition. In dogs, we have evaluated the potential benefit of insoluble and soluble dietary fiber on satiety in dogs that have been restricted to an energy intake appropriate for weight reduction. Results of a series of studies have failed to show any benefit of either fiber type on satiety in energy-restricted dogs.