Effects of neutering on food intake, body weight and body composition in growing female kittens

Abstract

To understand the effects of neutering on food intake, body weight (BW) and body composition in kittens, data from an unrelated study were subjected to post hoc analysis. A total of twelve pairs of 11-week-old female littermates were randomly assigned to either a neutered group (neutered at 19 weeks old) or an entire group (kept entire) and offered free access to a dry diet until the age of 1 year. Neutered kittens exhibited increased food intake and increased BW after neutering (both P, 0·00 001). Food intake (per kg BW) peaked 10 weeks after neutering; the mean intake of neutered kittens was 17 (95 % CI 8, 27) % more than entire littermates (P¼ 0·00 014). The intake was then reduced until there was no significant difference between the groups 18 weeks post-neutering. By 52 weeks of age, the neutered kittens were 24 (95 % CI 11, 39) % heavier than entire littermates (P, 0·0001) with a body condition score (BCS) 16·6 (95 % CI 0·9, 34·8) % higher (P¼0·0028). Neutered kittens continued to grow significantly fatter after neutering (all P, 0·0014), while entire kittens showed no significant change after 18 weeks of age. As neutered kittens consumed similar amounts of energy to their entire littermates from 18 weeks post-neutering, while their BW, BCS and percentage fat continued to increase, we suggest that neutered kittens have a reduced metabolisable energy requirement, and should therefore be fed to maintain an ideal BCS rather than ad libitum. Moreover, to maintain an ideal BCS, entire kittens consumed 93 (95 % CI 87, 100) % of their theoretical intake at 26 weeks of age, and 79 (95 % CI 72, 87) % at 52 weeks of age, suggesting that the current energy recommendation is inappropriate for these kittens.Key words: Cats: Kittens: Neutering: Food intake: Energy requirements: Body composition Throughout the developed world, cat obesity rates are rising, with approximately 30 -40 % of cats in the USA being obese or overweight (1) . Although obesity can occur in both neutered and intact cats, data suggest that neutered cats are more likely to become obese than sexually intact cats (1) . Neutering rates for both pet male and female cats are high in the developed world and many cats are neutered before 1 year of age (2,3) . Furthermore, in an effort to control the stray and pet cat populations, early neutering is recommended as the most appropriate surgical choice (4) . Long-term studies (5) have not identified early neutering (before puberty) as a risk factor for increased obesity v. traditional age neutering (7 months of age) and neutering studies carried out in pre-pubertal v. sexually mature kittens have not identified any differences in body weight (BW) and body condition score (BCS) in adulthood (6,7) , and the effects on individual feeding behaviour have also not been measured.The food intake in ad libitum-fed cats increases after neutering, and it has been shown that intake needs to be reduced by 20 -30 % to prevent BW gain (8,9) , and one study has suggested that neutered female cats have a peak in food i...

The impact of time of neutering on weight gain and energy intake in female kittens

“…Neutering was performed as part of normal veterinary practice at WALTHAM and occurred at one of two time points, one defined as early (early neutering; EN), at 19 weeks of age and the other, defined as conventional (conventional neutering; CN), at 31 weeks of age. Whilst neutering may occur earlier (6–12 weeks of age), 19 weeks is consistent with a previous study ( 11 ) , where cats were fed a dry diet ad libitum . The choice of 31 weeks as a later time point is not a specific ‘conventional’ time but is consistent with neutering following sexual development and was primarily to allow an entire control group for the longest time within current husbandry practice at WALTHAM.…”

“…The total energy requirement (TER) study reported here (female cats neutered at 19 and 31 weeks) in the left-hand panel is compared with data from two previous trials that were carried out at the WALTHAM Centre for Pet Nutrition at different times and with different dietary management regimens. The ‘self-regulated’ trial ( 11 ) (middle column) describes data from a study where the intake and weight data were obtained from female cats fed a commercial dry diet ad libitum and where cats neutered at 19 weeks of age were compared with a group that remained entire to 1 year of age. The macronutrient profile (MNP) food selection trial (right-hand column; AK Hewson-Hughes, VL Hewson-Hughes, R Staunton and SJ Simpson, Raubenheimer D, unpublished results) measured daily intakes from female cats offered excess of each of three wet diets differing in macronutrient composition at each meal, enabling them to select a macronutrient composition and eat ad libitum , where the neutered group was neutered at 26 weeks of age and compared with an entire group to 1 year of age.…”

“…1, macronutrient profile; right-hand column). The self-regulated study ( 11 ) observed that neutered cats consumed similar energy intakes to entire littermates from 37 weeks of age but continued to gain weight and percentage fat and speculated that reduced activity levels may be partly responsible for this reduced energy requirement. We measured activity in this study and saw no difference between groups at any time point.…”

Relationship between age at gonadectomy and health problems in kittens adopted from shelters

“…Overweight in cats is a known risk factor for lameness (Scarlett and Donoghue 1998) as well as for traumatic fractures at the capital femoral epiphysis (Craig 2001). Unlike the plethora of studies comparing obesity in gonadectomised versus entire animals regardless of time of gonadectomy (Fettman and others 1997, Robertson 1999, Allan and others 2000, Martin and others 2001, Lund and others 2005, Colliard and others 2009, Courcier and others 2010), few studies have specifically addressed the relationship between age at time of gonadectomy and the development of overweight in cats (Stubbs and others 1996, Root and others 1996b, Alexander and others 2011). It is well established that gonadectomy is one of the important predisposing factors for the development of overweight and obesity in cats (Robertson 1999, Lund and others 2005, Colliard and others 2009, Courcier and others 2010, Joyce and Yates 2011).…”

A moderate fat, low-energy dry expanded diet reduces gain in body condition score when fed as part of a post neutering weight-control regimen in growing pet cats

“…Previous research in laboratory settings has established the importance of reducing cats' post-neutering energy intake through controlled feeding ( 11 ) as well as the efficacy of feeding a low-energy-dense diet in decreasing post-neutering weight gain in cats ( 7 ) . However, methods that are successful under controlled laboratory conditions have the potential to be less effective in a real-world setting ( 9 ) .…”