Fleece-Lined Whelping Pools and Hip Dysplasia in a Guide Dog Program

Canine hip dysplasia (CHD) is an orthopedic condition that affects the hip joints of dogs, where the ball-and-socket joint of the hip does not align properly. This misalignment can lead to arthritis, chronic pain, and reduced mobility as the dog ages. CHD is one of the most common orthopedic disorders in dogs and is particularly prevalent in larger breeds.
A dog’s risk of CHD diagnosis is influenced by both genetic and environmental factors. Selective breeding programs, such as the one at Guide Dogs for the Blind (GDB), reduce the genetically inherited risk by carefully screening all breeding candidates and their close relatives. But while genetics play a significant role in CHD, environmental factors also interact with genetic predispositions to influence the likelihood of a CHD diagnosis later in life.
One such factor is the physical environment in which puppies are raised during their neonatal period—the first few weeks after birth. During this critical time, a puppy’s bones, muscles, and joints are rapidly developing. The type of bedding used in whelping pools—the spaces where puppies are born and raised—may significantly affect this development.
Traditionally, newspaper bedding has been a common choice for whelping pools due to its low cost, ease of cleaning, and availability. However, it can be slippery, which may force puppies to adopt abnormal postures or movements that could stress their developing joints. Fleece-lined bedding, on the other hand, provides a softer and more grippy surface. This material can help puppies maintain a more natural posture and movement, potentially reducing the risk of strain on their hip joints during critical developmental stages.
At GDB, the health and well-being of our dogs are continually monitored, and evidence-based practices inform decisions about their care. In 2016, GDB switched from lining whelping pools with newspaper to lining them with fleece. This study explored differences between CHD prevalence before and after the switch in order to evaluate how newspaper and fleece bedding influence the development of CHD within our population. Our Research Team analyzed historical records of 5,649 dogs, including Labrador Retrievers, Golden Retrievers, and Labrador–Golden Retriever crosses. Puppies fell into two groups based on the type of bedding used in their whelping pools during the first three weeks after birth: newspaper bedding or fleece-lined bedding.
What did we find? We confirmed that rates of CHD are quite low to begin with in GDB dogs compared to those reported in the literature. However, there was a compelling difference based on bedding type used in the whelping pools. Puppies raised on fleece-lined bedding had a lower risk of being diagnosed with CHD than those raised on newspaper bedding.

Three graphs of hip dysplasia incidence rate by dogs’ whelp year split by breed group ((a) Labrador Retriever, (b) Golden Retriever, (c) Labrador–Golden Retriever cross). A vertical line between 2015 and 2016 on each graph reflects the two treatment groups (newspaper for puppies whelped between 2012 and 2015 and fleece for puppies whelped between 2016 and 2019). Data labels below each year show the proportion of dogs diagnosed with hip dysplasia out of all dogs of that breed who were whelped that year.
Among the breeds studied, Golden Retrievers exhibited the highest risk for CHD, followed by Labrador–Golden Retriever crosses. Labrador Retrievers had the lowest risk. No significant differences were found between male and female dogs in CHD diagnoses.
These findings suggest that environmental factors, such as the type of bedding in whelping pools during the neonatal period, may influence the development of CHD in dogs and highlight the importance of considering early environmental conditions in efforts to prevent orthopedic issues in dogs. For more details, you can access the full peer-reviewed publication freely here.