Advancing Genetic Selection and Behavioral Genomics of Working Dogs Through Collaborative Science.

The ancient partnership between people and dogs is struggling to meet modern day needs, with demand exceeding our capacity to safely breed high-performing and healthy dogs. New statistical genetic approaches and genomic technology have the potential to revolutionize dog breeding, by transitioning from problematic phenotypic selection to methods that can preserve genetic diversity while increasing the proportion of successful dogs. To fully utilize this technology will require ultra large datasets, with hundreds of thousands of dogs. Today, dog breeders struggle to apply even the tools available now, stymied by the need for sophisticated data storage infrastructure and expertise in statistical genetics. Here, we review recent advances in animal breeding, and how a new approach to dog breeding would address the needs of working dog breeders today while also providing them with a path to realizing the next generation of technology. We provide a step-by-step guide for dog breeders to start implementing estimated breeding value selection in their programs now, and we describe how genotyping and DNA sequencing data, as it becomes more widely available, can be integrated into this approach. Finally, we call for data sharing among dog breeding programs as a path to achieving a future that can benefit all dogs, and their human partners too.

Incidence and risk factors for canine mastitis and metritis in two guide dog populations.

Canine mastitis and metritis can cause severe illness but the incidence and risk factors have not been well-studied. Goals in the present study were: 1) report the incidence of mastitis and metritis in a large population, and 2) identify potential risk factors that predispose females to those diseases. A retrospective cohort study was conducted using data from two guide dog colonies that was collected for 17 and 10 years, respectively, for the two colonies. A total of 3076 whelpings occurred during the respective study periods and data were analyzed. Clinical mastitis was diagnosed in 13.2 % of whelpings (408 cases) with the average day of diagnosis being 16.7 postpartum. Risk factors for mastitis identified were colony, litter size where bitches that had large litter size of ≥9 pups (16.2 %) were 60 % more likely to develop mastitis compared with bitches that had litters of <9 pups (11.3 %). Bitches with congestion of the mammary gland were 4.8 times more likely to develop mastitis compared with bitches without mammary congestion. Case incidence of metritis was small (0.7 % of whelpings) and occurred on average at day-5 postpartum (range 1-16). There were no significant risk factors identified, and this may be due to the small number of metritis cases (22 cases) in the present study. Interpretations regarding metritis, therefore, should be made with caution. The results from this study provide parameters for breeders and veterinarians to identify bitches that may require close monitoring for mastitis and metritis.

Heritabilities for the puppy weight at birth in Labrador retrievers.

BACKGROUND: Weight at birth is an important predictor of neonatal mortality and morbidity in dogs. In addition, the birthweight of the puppies in a litter influences the decision to perform a cesarean section. The goal of the present study was to estimate heritabilities for the puppy birth weight in Labrador retrievers. RESULTS: Of the 1138 Labrador retriever litters whelped at the Guiding Eye for the Blind between September 2001 and February 2018, 1013 were included in the analyses after data editing. Puppy weight at birth was the target trait, measured on a continuous scale in pounds, and converted to grams. Linear mixed models were used to identify factors influencing puppy weight at birth. The analyses showed that the sex of the puppy, litter size, length of gestation, adult weight of the dam, parity, year of birth and inbreeding coefficient of the puppies and dams contributed to the variance of the puppy birth weight. Dam and litter effects were included as random effects. A multiple trait derivative free restricted maximum likelihood approach was used to estimate variance components and genetic parameters with two animal models, one without covariates (Model 1) and one with covariates (Model 2). Sex of the puppy and litter size had moderate effects, whereas gestation length, adult weight of the dam, parity, year of birth and inbreeding coefficients of the dam and the puppies had minor effects. Estimates for Model 1 and Model 2 were 0.21 and 0.17 for the direct heritabilities, 0.22 and 0.22 for the maternal additive genetic heritabilities, 0.07 and 0.07 for the maternal permanent environmental proportions, and 0.14 and 0.08 for the environmental proportion of the litter. CONCLUSIONS: In order to estimate reliable breeding values for puppy weight at birth, sex of puppy, litter size, length of gestation and the adult weight of the dam should be included. Estimates could benefit from weighing the dams prior to each mating.

Identifying risk factors for canine dystocia and stillbirths.

Canine dystocia is a common problem that increases the risk of mortality to the dam and stillbirths for the pups. Understanding the risk factors for dystocia and stillbirth can help guide decision making to improve outcomes of whelping management. This study aimed to 1) evaluate risk factors for canine dystocia; and 2) assess risk factors for stillbirth in puppies, by examining all whelpings and puppies born in two breeding populations of guide dogs for a defined period of time. Dystocia risk factors were evaluated using a repeated measures model on 2,489 litters with an overall dystocia rate of 23.8%. Risk factors identified for dystocia were colony, litter size, and age of dam. Small litter size (<5 pups) had the highest dystocia rate of 36.5%, large litter size (>9 pups) had an intermediate dystocia rate of 26.9% and medium litter size had the lowest dystocia rate of 22.1%. Dystocia risk increased as the age of dam increased. Stillbirth risk factors were evaluated for 19,577 pups and the overall stillbirth rate was 5.9%. Risk factors identified for stillbirths were dystocia, litter size, cesarean section performed and breed. Pups from litters that had dystocia were 2.35 times more likely to be stillborn compared with normal litters born without dystocia. Stillbirth risk increased as litter size increased. Pups from litters of 11 or more pups were 1.45 times more likely to be stillborn. Specific information was available for a subset of pups and was used to evaluate the association with stillbirth. Low birth weight was associated with increased stillbirth risk but large pups were also at higher risk of stillbirth compared with average size pups. Stillborn pups had longer mean (102 vs 65 min) and median (47 and 32 min) inter-pup intervals compared with live pups. The positive predictive values for stillbirth were 13.5%, 28.4%, 31.8% and 36.5% when inter-pup interval threshold was set at 1, 2, 3 and 4 h respectively. There is a tradeoff between over diagnosing stillbirth and increased positive predictive value for stillbirth when inter-pup interval threshold is extended but the improvements were modest after 2 h. The last pup born in a litter regardless of litter size was significantly more likely to be stillborn. In conclusion, this paper details data driven parameters to use when making the decision to intervene during whelping that optimize survival for dams and puppies.

Factors contributing to the decision to perform a cesarean section in Labrador retrievers.

BACKGROUND: In the past 10 years, the frequency of unplanned cesarean sections in the Labrador Retriever breeding colony at Guiding Eyes for the Blind stayed around 10% (range 5% to 28%). To reduce the number of cesarean sections, factors influencing the occurrence of a cesarean section need to be known. The goal of this study was to identify factors that contribute to the decision to perform a cesarean section. RESULTS: Of the 688 Labrador Retriever litters whelped between 2003 and 2016, 667 litters had sufficient data and remained in the analysis. The target trait was ordinal with the three levels "normal whelping", "assisted whelping" and "cesarean section". A general ordinal logistic regression approach was used to analyze the data. Model selection with possible predictors resulted in a final model including weight of the dam, the weight of the heaviest puppy of a litter, the number of fetuses malpositioned and the quality of uterine contractions. Weight and size of a litter, parity, maternal inbreeding coefficient, whelping season, dam and sire were dropped from the model because they were not significant. The risk of a cesarean section was influenced by the combination of the weight of the dam and the weight of the heaviest puppy in the litter, as well as by the number of malpositioned fetuses and the quality of the contractions. Larger puppies increased the risk of cesarean section especially when the dam had a lighter weight. For dams weighing 23.6 kg and 32.8 kg the predicted probability of a cesarean section was low, with 0.06 and 0.02, respectively, when the heaviest puppy in a litter was light (0.42 kg), contractions were normal and no fetus was malpositioned. However, the probability of a cesarean section was much higher, ranging from 0.24 to 0.08, when the heaviest puppy in a litter was heavy (0.66 kg). CONCLUSIONS: Means to reduce the cesarean section frequency in this Labrador Retriever breeding colony should include genetic selection for ideal puppy weight. In addition, dams with an adult body weight substantially below average should not be selected as breeders in this colony.