What Is The Best Age To Neuter A Shi Tzu?

Updated July 28, 2022

Whether you call it neuter, spay, castrate or desex, the right time to get it done in dogs is a subject of much debate. This is because it varies from breed to breed. Recently, a study was published on the best age for neutering in Shi Tzus.

While the paper isn’t perfect (more on that later), it does provide the first evidence for Shi Tzus on choosing a time of desexing with the fewest health problems. The study compared dogs neutered at different ages for their rates of:

• hip dysplasia (HD), cruciate ligament injury (CCL) and elbow dysplasia (ED)
• lymphoma (LSA), mast cell tumour (MCT), haemangiosarcoma (HSA), osteosarcoma (OSA)
• urinary incontinence (UI)

All of these have been suspected to be linked with the age of neutering. Here’s what they found (only bold values are significant, my summary to follow):

	HD	CCL	ED	At Least One
Male < 6 months	0/19 (0)	0/19 (0)	0/18 (0)	0/18 (0)
Male 6 – 11 months	0/45 (0)	0/45 (0)	0/45 (0)	0/45 (0)
Male 1 year	0/20 (0)	0/20 (0)	0/20 (0)	0/20 (0)
Male 2 – 8 years	0/25 (0)	0/25 (0)	0/25 (0)	0/25 (0)
Male Intact	0/103 (0)	0/104 (0)	0/104 (0)	0/103 (0)
Female < 6 mon ths	0/22 (0)	0/22 (0)	0/22 (0)	0/22 (0)
Female 6 – 11 months	0/47 (0)	0/47 (0)	0/47 (0)	0/47 (0)
Female 1 year	0/17 (0)	0/16 (0)	0/17 (0)	0/16 (0)
Female 2 – 8 years	0/47 (0)	0/47 (0)	0/47 (0)	0/47 (0)
Female Intact	0/77 (0)	0/77 (0)	0/77 (0)	0/77 (0)

	LSA	MCT	HSA	OSA	At Least One
Male < 6 months	0/19 (0)	0/19 (0)	0/19 (0)	0/19 (0)	0/19 (0)
Male 6 – 11 months	0/44 (0)	0/45 (0)	0/45 (0)	0/44 (0)	0/44 (0)
Male 1 year	0/20 (0)	0/20 (0)	0/20 (0)	0/20 (0)	0/20 (0)
Male 2 – 8 years	0/25 (0)	0/25 (0)	0/25 (0)	0/25 (0)	0/25 (0)
Male Intact	0/104 (0)	0/104 (0)	0/104 (0)	0/104 (0)	0/104 (0)
Female < 6 mon ths	0/22 (0)	0/22 (0)	0/22 (0)	0/22 (0)	0/22 (0)
Female 6 – 11 months	2/46 (4.35)	1/47 (2.13)	0/46 (0)	0/47 (0)	3/46 (6.52)
Female 1 year	2/17 (11.76)	1/17 (5.88)	0/17 (0)	0/17 (0)	3/17 (17.65)
Female 2 – 8 years	0/45 (0)	0/47 (0)	0/47 (0)	0/47 (0)	0/45 (0)
Female Intact	0/76 (0)	0/77 (0)	0/77 (0)	0/77 (0)	0/76 (0)

UI was not reported in any of the spayed females.

Summary: The Best Shi Tzu Spay & Neuter Times

There is minimal evidence that Shi Tzu health problems are influenced by the age of neutering other than an increase in cancer noted in females spayed over 12 months of age.

Recommendation: 6 months for both sexes.

This is so far the only science we have for the best desexing age in Shi Tzus. Your vet, breeder or online group may have a different opinion based on their experience or personal beliefs. It’s perfectly reasonable to take their advice into consideration as well.

Problems With This Study

The authors do not mention the well-known increase in lifespan associated with desexing male and female dogs, which tends to counteract most concerns about specific cancers. The following comment in the paper is a clue that it might also have been true for this population:

Across all breeds the mean age of last entry in the record for neutered males was 5.5 years (range 3.71–6.54), for neutered females 5.7 years (range 4.21–6.97), for intact males 4.9 (range 4.15–7.11), and intact females 4.7 (range 3.41–6.32)

The study tries to also look at the rates of mammary cancer & pyometra in females, but cannot give an accurate assessment for two reasons:

1. the mean ages listed above are far too young to pick up most cases
2. pyometra and mammary cancer are rarely referred to university hospitals

Regardless of any concerns, the authors are to be applauded to bringing into focus one of the most common questions from dog owners. For the Shi Tzu at least, they’ve made the decision a lot easier.

Related: Best Desexing Age For 35 Breeds | Desexing Choices For Dogs | Costs Of Desexing

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By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.