Publication Database

Perils and pitfalls of research on effects of neutering of dogs (2022)

Art

Vortrag

Autor

Arlt, Sebastian P. (WE 19)

Kongress

23rd Congress of the European Veterinary Society for Small Animal Reproduction (EVSSAR)

online, 01. – 02.10.2021

Quelle

Reproduction in domestic animals = Zuchthygiene

Bandzählung: 57

Heftzählung: Supplement 2

Seiten: 63 – 64

ISSN: 0936-6768

Sprache

Englisch

Verweise

URL (Volltext): https://onlinelibrary.wiley.com/doi/full/10.1111/rda.14066

DOI: 10.1111/rda.14066

Kontakt

Tierklinik für Fortpflanzung

Königsweg 65
Haus 27
14163 Berlin
+49 30 838 62618
fortpflanzungsklinik@vetmed.fu-berlin.de

Abstract / Zusammenfassung

Frequently, dog owners ask their vets for counseling regarding pros and cons and optimal time for neutering of female dogs. This task is complex and should include recent and valid research data (1). In the past decades, several case reports, observations from different countries such as the United States or Sweden with different habits or legal regulations – i. e. very frequent early neutering vs. almost no neutering – and cohort studies have been published. Cohort studies are prospective or retrospective and usually compare an exposed with an unexposed group (cohorts). The outcome is measured after a specific time. For example, one could assess the incidence of a disease in a cohort of neutered dogs compared with a cohort of intact dogs.
An advantage of neutering a female dog is that ovarian diseases and metropathy do not occur anymore. In addition, some studies have shown that early neutering reduces the risk of mammary neoplasia to a certain extent, even if the scientific basis for this observation is weak. The effect might be smaller than some older publications suggest (1). Disadvantages of neutering female dogs include urinary incontinence, a higher risk of different types of neoplasia and musculoskeletal disorders. Some of these phenomena might be based on hormonal changes. It has been shown that GnRH and FSH and LH are upregulated in neutered dogs because of the missing negative feedback from the gonadal steroids. Overall, the scientific evidence needs to be improved. In many studies small numbers of animals are used which impedes the generalizability of the findings. Often incomplete data about the dogs is presented. A lot of research findings are derived from necropsies during which it can be defined if a dog is neutered or not but often nothing is known about the age at neutering or other aspects of the reproductive and medical history.
In many studies comparability of the animals of a neutered and an intact cohort may not be given. For example, a data analysis of 2.2 million dogs has been published, showing that neutered dogs become in average more than two years older (2). Sadly, the authors did not take potential confounders into account. Therefore, the presented differences in the life span may more rely on the living conditions of the dogs rather than on the neuter status. It can be assumed that the neutered dogs were living with a family since their puppy age under good medical care including vaccinations, deworming, neutering and health surveillance. The intact dogs may be kennel or stray dogs, which have never been taken to a vet and maybe even do not get food of sufficient quantity and quality. In some cases it may be difficult to judge retrospectively, which was cause and which was effect. For example neutering might lead to a higher risk of cruciate ligament ruptures (CLR). On the other hand, breeders might let their vets neuter a dog after a diagnosis of CLR because this dog is not suitable for breeding anymore. In research also breed specific aspects need to be considered, especially when it comes to incontinence or other diseases with a well know breed specific incidence. Finally, potential confounders may influence each other. For example, if neutered dogs become obese, this may increase the risk for musculoskeletal disorders or other diseases.
Conclusion: Interpretation of research data on the effects of neutering dogs is difficult. If we consider specific questions and read new
publication, we need to assess if the data and conclusions given are really objective and robust.
References
1. Arlt et al. (2017): Theriogenology 79:9. 1278- 1283
2. Banfield Group (2013): https://www.banfield.com/about-banfield/newsroom/press-releases/2013/spaying-and-neutering-may-contribute-to-longer-lif