The Institute of Canine Biology
  • HOME
  • Blog
  • Breed Preservation
    • Breeding for the future >
      • BFF Breed Groups
    • Breed Status
    • The "Elevator Pitch"
    • What's in the Gene Pool?
    • What population genetics can tell us about a breed
    • What population genetics can tell you...Tollers & Heelers
    • How to use kinship data
    • Using EBVs to breed better dogs >
      • How population size affects inbreeding
      • EBV Examples
    • How to read a dendrogram
    • Global Pedigree Project >
      • The Database
    • Finding the genes without DNA
    • How to read a heat map
  • Courses
    • COI BootCamp (FREE!)
    • Basic Population Genetics (FREE)
    • Genetic rescue: the genetics of cross breeding (NEW!)
    • The Biology of Dogs (Open Reg )
    • Managing Genetics For the Future >
      • Managing Genetics For the Future Open Reg (Open Reg) >
        • Syllabus - Managing Genetics for the Future
    • Genetics of Behavior & Performance (Open Reg)
    • Strategies for Preservation Breeding (Open Reg)
    • DNA For Dog Breeders (May2025) >
      • DNA For Dog Breeders (Open Reg)
    • Understanding Hip & Elbow Dysplasia (Open Reg) >
      • MORE FREE COURSES >
        • Quickie Genetics (Free!)
        • Group Discounts
        • Useful Genetics (Free!)
        • Strategies for Preservation Breeding (Sept 2023) >
          • Heredity & Genetics (Free!)
        • Basic Genetics Videos
  • Health Data
    • Bloat (Purdue Study)
    • Body Condition Score >
      • % Dysplastic vs BCS
    • Breed Comparions
    • Cancer
    • Cardiac
    • Cataracts
    • Caesareans
    • Deafness
    • Degenerative Myelopathy
    • Elbow Dysplasia
    • Epilepsy
    • Genetic Diversity
    • Genetic Diversity (MyDogDNA)
    • Hip Dysplasia >
      • Hip Dysplasia (Hou et al 2013)
    • Metabolic
    • Inbreeding Effects
    • Inbreeding (Gubbels)
    • Inbreeding (Dreger)
    • Lifespan
    • Litter size
    • mtDNA
    • Orthopedic
    • Mode of Inheritance
    • Patella Luxation
    • Thyroid
    • Portosystemic shunt
    • Purebred vs Mixed (UC Davis)
    • Purebred vs Mixed Breed (Bonnett)
    • Spay & Neuter Effects
    • Calboli et al 2008
    • Hodgman (1963)
    • Scott & Fuller (1965)
    • Stockard: Purebred crosses
    • Summers (2011)
  • Projects
    • How To Interpret Breed Analyses
    • Afghan Hound
    • More details about the Toller study
    • Belgian Tervuren >
      • Belgian Terv p2
      • Belgians- why population size matters
    • Bernese Mountain Dog
    • Boxer
    • Brussels Griffon
    • Bullmastiff
    • Canaan Dog >
      • Canaan analyses
    • Cesky Terrier >
      • Cesky genetic history
    • Chinook
    • Curly-coated Retriever
    • Doberman
    • Entelbucher Mountain Dog
    • Flatcoat Retriever
    • French Bulldog
    • German Shorthair
    • Golden Retriever >
      • Golden Retriever Pedigree Charts
    • Irish Water Spaniel >
      • IWS (6 Nov 17)
    • Labrador Retriever
    • Manchester Terrier
    • Mongolian Bankhar >
      • Research Updates
      • Bankhar 1
    • Norwegian Lundehund
    • Plummer Terrier
    • Otterhound
    • Portuguese Water Dog >
      • Portuguese Water Dog (pt 2)
    • Ridgeback
    • Schipperke
    • Standard Poodle >
      • The Problem With Poodles
      • 3poodle pedigree charts
      • 3Poodle Wycliff dogs
      • Poodle Genetics
    • Tibetan Spaniel
    • Tibetan Mastiff
    • West Highland White Terrier
    • Whippet
    • Wirehaired Pointing Griffons
    • UK KC Graphs >
      • UK KC Breed Status
      • UK Groups
      • KC Gundogs
      • KC Hounds
      • KC Terriers >
        • Terriers (select breeds)
      • KC Pastoral
      • KC Toys
      • KC Working
      • KC Utility
      • Australian KC
    • Breed outcrossing programs
  • Resources
    • Genetics Databases
    • Stud Books >
      • American Kennel Club stud books
      • Field Dog stud books
      • The Kennel Club (UK)
    • Learn
    • Videos about dog genetics
    • The Amazing Things Dogs Do! (videos) >
      • Livestock Management
      • Livestock guarding
      • Transportation, exploration, racing
      • Conservation & wildlife management
      • Detection Dogs
      • Medicine & Research
      • Entertainment
      • AKC/CHF Podcasts
    • Read & Watch
    • Bookshelf

Why do so many puppies die?

4/14/2023

 
By Carol Beuchat PhD
​Anyone that has been breeding very long has had the experience of excitedly welcoming a new litter of puppies into the world, only to have a beautiful, perfectly-formed puppy born dead. Oftentimes, there are puppies with signs of life but are struggling. Some of these can be revived but, sadly, some cannot despite the best efforts of the breeder.

Perhaps the worst is loss is a puppy that seems to be doing well for several days, then without warning is found dead in the whelping box.

This mortality represents a very significant loss of the puppies produced by breeders. In fact, the statistics are shocking. 
Picture
In a large study that included 2,574 puppies from 500 litters of 44 breeds (Gill 2001), the total puppy mortality from birth to six weeks averaged 18.5%, with 7% of puppies stillborn. About 10% of liveborn puppies died within the first 7 days.
​

There is detailed information about this study (Gill 2001):
Picture
Picture


​What is causing such high rates of mortality in puppies?

Excluding the puppies with evident abnormality, the necropsy information for the puppies in Gill's (2001) study (see below) shows that the stillborn puppies suffered from in utero hypoxia - they ran out of oxygen before they were born. In fact, even the puppies that were born live and lived for days also often show evidence of hypoxia (inadequate oxygen) in utero (from Gill 2001). (See necropsy reports below)
Using data for the time of birth of each consecutive puppy, you can compute the "inter-pup interval" as an estimate of how long it takes each puppy to be born (assuming that the placenta was detached at the beginning of that period).

​This graph shows that a longer interval between puppies increases the risk of stillbirth. (The first point on the graph represents puppies with inter-pup intervals from 0 to 60 minutes; the marker is placed at 30 min.) 
​
​
Picture

So, as the time between births increases, the proportion of stillborn puppies increases.

But why does birth of puppies take so long? 

The pace of labor is determined by the contractile behavior of the uterus. Prolonged labor is the result of "uterine inertia", which is a failure of the uterus to contract with sufficient strength and frequency to expel the puppy.
If we could prevent uterine inertia, we could potentially greatly reduce puppy mortality, both as stillbirths and for puppies that survive for days or even weeks but ultimately die.

So finally, we can ask the critical question:

​What causes uterine inertia and how can we prevent it?
When I ran into this issue of high puppy mortality, I was surprised that it had not been resolved long ago. After all, we can determine cause of death, and for most puppies it seems to be a matter of physiology (hypoxia), not a mysterious pathogen or anatomical abnormality. The high mortality of puppies has been well documented, but several studies that searched for a cause came up empty.

If puppies are suffocating in utero because of uterine inertia, then that's the problem we need to solve.

I found various suggestions of possible causes (e.g., overstretching of the uterine muscle, exhaustion of the uterus), but no explanation in the canine or veterinary literature.

However, I stumbled on what I think is the answer.

Uterine contractions during labor are affected by light. 
Here are some representative data for uterine contractions during labor in a human. Starting in a dark room, the frequency of contractions increases by the hour. If a light is turned on for an hour, the contraction rate drops dramatically to only 1/hr. When the light is turned off, contractions recover slowly.

​
Picture


But does this also happen in dogs? In fact, it looks like it does.

My colleagues and a group of cooperative breeders have found that bitches kept in a room with lights on typically produce a couple of puppies, but then there is often a prolonged interval before the next puppy appears. In the meantime, the bitch is typically restless and producing strong abdominal contractions. When puppies are produced, the intervals between them can be protracted - an hour or two, or sometimes many hours or even the next day.

But we have found that when the whelping box is in a dark room - a VERY dark room - the bitch is relaxed and calm, and the puppies are expelled quickly and easily, without straining and abdominal contractions. The pups are vigorous as soon as they emerge from the membranes, and the bitch tends to each without assistance.

Most notably, as long as the whelping room stays dark, there are no stillborns or puppies needing reviving. 

However, if a light are turned on, even very briefly, the strong abdominal contractions resume, but there are long intervals between puppies. Some of these puppies are born with fluid in the respiratory tract or need to be revived, and some can be stillborn.
Could reducing puppy mortality be as simple as whelping in the dark? I think it can be.

​After all, dogs left to their own devices dig a den for their pups, and they are typically born at night. When we bring dogs indoors to manage their reproduction, they are denied this opportunity, although who hasn't found their pregnant bitch under the bed or in the back of a closet when the time comes near for whelping. For tens of thousands of years, dogs have produced their puppies in the darkness of an underground den, and we should expect that their reproductive physiology is suited for this. The consequence of whelping in the light instead of darkness is high puppy mortality. Natural selection would weed out the non-conformers rather quickly.
ICB Uterine Inertia and Neonatal Mortality

​If you are interested in following the progress of this study or would like to participate with your own upcoming litter, please join the Facebook group created for this project at -
​

https://www.facebook.com/groups/uterineinertiaindogs
If light is the key to reducing puppy mortality, it could have huge implications for canine husbandry. Not only would there be fewer losses to morbidity and mortality, there would also be fewer emergency c-sections to recover puppies trapped by unproductive labor, and less risk of losing a bitch because of a difficult labor.

The significance of this doesn't escape me. We will need to do some careful studies to verify the effects of light and darkness on whelping, and there is a long list of questions about effects on physiology and behavior that should be addressed. But as problems go, this one is potentially very easy to solve. And it will result in more puppies. That's definitely a win.

VIDEO: Bernese Mountain Dog, dark whelping. 

This is typical for bitches whelping in the dark. The bitch is relaxed and not straining. The puppy emerges quickly and mom takes caresof it to remove membranes and lick clean. (Watch carefully!)

NECROPSY REPORTS

Pathology of Stillborn Puppies
Picture

​
​Pathology of puppies that survived up to 10 days
Picture


​Pathology of Puppies That Survived < 48h
Picture


​Column labels for table of breed statistics below (Tonnessen et al 2012).
Picture
Picture

Picture

REFERENCES

Cornelius AJ et al, 2019. Identifying  risk factors for canine dystocia and stillbirths. Theriogenology 128: 201-206.

Gill, MA, 2001. Perinatal and late neonatal mortality in the dog. PhD Thesis, University of Sydney.
​
Tonnessen R et al, 2012. Canine perinatal mortality: a cohortt study of 224 breeds. Theriogenology 77: 1788-1801.

To learn more about the genetics of dogs, check out
ICB's online courses

***************************************

Visit our Facebook Groups

ICB Institute of Canine Biology
...the latest canine news and research

ICB Breeding for the Future
...the science of animal breeding



Comments are closed.

    Archives

    January 2030
    February 2025
    January 2025
    December 2024
    November 2024
    October 2024
    July 2024
    June 2024
    May 2024
    March 2024
    February 2024
    July 2023
    April 2023
    November 2022
    July 2022
    May 2022
    April 2022
    March 2022
    February 2022
    November 2021
    October 2021
    December 2020
    January 2020
    August 2019
    July 2019
    June 2019
    May 2019
    April 2019
    March 2019
    February 2019
    January 2019
    December 2018
    November 2018
    September 2018
    August 2018
    July 2018
    June 2018
    May 2018
    October 2017
    August 2017
    May 2017
    April 2017
    March 2017
    February 2017
    January 2017
    December 2016
    November 2016
    September 2016
    August 2016
    July 2016
    June 2016
    April 2016
    March 2016
    February 2016
    January 2016
    December 2015
    November 2015
    October 2015
    September 2015
    August 2015
    July 2015
    June 2015
    May 2015
    April 2015
    March 2015
    January 2015
    December 2014
    November 2014
    October 2014
    September 2014
    August 2014
    July 2014
    June 2014
    May 2014
    February 2014
    December 2013
    October 2013
    September 2013
    July 2013
    March 2013
    July 2012
    April 2012

    Categories

    All
    Behavior
    Border-collie
    Herding

Blog

News


About Us

Contact Us








Copyright © 2012-2017 Institute of Canine Biology
Picture
Picture