Comparison of growth in neutered Domestic Shorthair kittens with growth in sexually-intact cats

PLoS One. 2023 Mar 15;18(3):e0283016. doi: 10.1371/journal.pone.0283016. eCollection 2023.

Abstract

The first aim of these studies was to compare growth patterns of healthy kittens neutered during growth with growth standards created for sexually-intact kittens. A second aim was to clarify the impact of neutering in kittens on body composition and body shape. Study 1 was a retrospective observational study comparing median growth trajectories of healthy, client-owned domestic shorthair (DSH) kittens in optimal body condition and neutered at different ages, with previously-created growth standards from a similar, sexually-intact, population. The neuter groups contained between 3.0k and 9.3k cats. For all neuter groups in both sexes, the median growth trajectory inclined upwards after the procedure, with this being more marked in female than in male kittens. This upwards inclination was less marked for kittens neutered later during growth in both sexes, with the effect being least in kittens neutered after 28-29 weeks. Study 2 was an analysis of new body composition and zoometric data from a previously-published randomised study, comparing growth-related measures between 11 pairs of sexually-intact and neutered (at 19 weeks age) female DSH cats in a research population. Before neutering, the growth pattern in neutered kittens and sexually-intact kittens was similar, but neutered kittens were heavier by 52 weeks (mean difference in fold change vs. 10 weeks 1.34, 95-CI: 1.07-1.72), had a greater fat mass (mean difference in fold change vs. 10 weeks 1.91, 95-CI 1.09-3.21) and greater lean mass (mean difference in fold change vs. 10 weeks 1.23, 95-CI: 1.03-1.48). Abdominal girth (mean difference in fold change vs. 10 weeks 1.20, 95-CI: 1.04-1.39) and rib cage length (mean difference in fold change vs. 10 weeks 1.18, 95-CI: 1.02-1.36) were also greater, but there were no differences in other zoometric measurements. Veterinarians should consider the potential impact that neutering has on gain of adipose tissue, especially early neutering in female kittens. Bodyweight should be monitored closely during growth and especially after neutering to prevent inappropriate weight gain.

Publication types

  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipose Tissue
  • Animals
  • Body Composition*
  • Body Weight
  • Cats
  • Female
  • Male
  • Weight Gain*

Grants and funding

The authors received no specific research grant funding for this work. However, Mars Inc. provided financial support comprising salaries for three authors (CS, KH and RB) and material support for both data collection (e.g., clinical data gathered from Banfield Veterinary Hospitals; research data from the Waltham Petcare Science Institute) and to conduct data analyses (e.g., IT support). Mars Inc. also provided financial support for the academic post of the fourth author (AJG) at the University of Liverpool. The University of Liverpool provided material support for this study author (e.g., IT and facilities support) and also IT support for hosting the online open-access datasets. Finally, the funder (Mars Inc.) provided material support for research ethics, comprising a review of study protocols by their Animal Welfare and Research Ethics Committees before project commencement, and an ethical and scientific review of the manuscript prior to submission. Neither the funder (Mars Inc.) nor the University of Liverpool had any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of each of the authors are articulated in the ‘author contributions section'.