Genetic variation in aggression-related traits in Golden Retriever dogs

Anna-Elisa Liinamo, Linda van den Berg, Peter A.J. Leegwater, Matthijs B.H. Schilder, Johan A.M. van Arendonk, Bernard A. van Oost

Genetic variation in aggression-related traits in Golden Retriever dogs

Applied Animal Behaviour Science, Volume 104, Issues 1–2, April 2007, Pages 95–106

Abstract

In this study, heritabilities of several measures of aggression were estimated in a group of 325 Golden Retrievers, using the Restricted Maximum Likelihood method. The studied measures were obtained either through owner opinions or by using the Canine Behavioural Assessment and Research Questionnaire (CBARQ). The aim of the study was to determine which of the aggression measures showed sufficient genetic variation to be useful as phenotypes for future molecular genetic studies on aggression in this population. The most reliable heritability estimates seemed to be those for simple dog owner impressions of human- and dog-directed aggression, with heritability estimates of 0.77 (S.E. 0.09) and 0.81 (S.E. 0.09), respectively. In addition, several CBARQ-derived measures related to human-directed aggression showed clear genetic differences between the dogs. The correlation between the estimated breeding values for owner impressions on human- and dog-directed aggression was relatively low. The low correlation suggests that these two traits have a partially different genetic background. They will therefore have to be treated as separate traits in further genetic studies.

Heritability of semen characteristics in dogs

G.C.W. England, L. Phillips, S.L. Freeman

Heritability of semen characteristics in dogs

Theriogenology, Volume 74, Issue 7, 15 October 2010, Pages 1136–1140

Abstract

Retrospective analysis was performed on semen collected from 24 dogs (parents: 14 Labrador retrievers and 10 Golden retrievers) aged between 16 and 28 months of age. The dogs were part of a large breeding programme but lived in the homes of volunteer families. The semen was subjected to a standardised examination procedure including assessment of: percentage normal motility, sperm concentration, total sperm output, percentage of live normal sperm, and total number of live normal sperm. Semen was subsequently collected from one son of each of the parents when the offspring were aged between 16 and 28 mo (offspring: 14 Labrador retrievers and 10 Golden retrievers), and was subjected to the same examination procedures conducted by the same technician. Examination of breeding records demonstrated that each of the 48 dogs achieved at least one pregnancy within a period of 3 months before to 3 months after the semen collection.

There was a weak correlation between parents and offspring for each of the 5 semen parameters, although none of these were statistically significant. Narrow sense heritability measures were low for all parameters except for the heritability of high sperm motility (rN2 = 0.57) and the heritability of low total sperm output (rN2 = 0.57).

It is plausible that breeding selection procedures may be useful in dog breeding programmes in an attempt to improve semen quality, although any impact upon fertility is yet to be proven.