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  • Author or Editor: Jan van de Broek x
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Abstract

Objective

To test validity of prediction for inherited portosystemic shunts (PSS) in Irish Wolfhounds, using nonselective clinical findings and a computerized database containing 5-generation pedigrees.

Animals

613 dogs in the first and 396 dogs in the second cohort.

Procedure

Preprandial venous ammonia concentration was measured at 6 to 8 weeks in all pups born between Jan 1, 1988 and Jan 1, 1997. Portosystemic shunts were confirmed in hyperammonemic pups, using radioisotope shunt index measurement, and diagnosis of shunting was confirmed at abdominal surgery or necropsy. Findings in dogs of the first cohort (born before Jan 1, 1992) were used to predict shunting in their offspring of the second cohort. Common ancestors of first-cohort dogs with shunts were tested for positive associations with the disease. Risk for a shunt in all second-cohort dogs was predicted on the basis of relatedness with founders and was compared with outcome of clinical screening.

Results

Prevalence of shunts in first and second cohorts was 3.1 and 2.3%, respectively. Fifteen highly related associated founders could be identified. Second-cohort dogs were classified into 6 groups of increasing predicted risk. Mean number of dogs per class was 60; number of clinically diagnosed cases ranged from 0 in the class with the lowest risk to 4 in the highest risk class.

Conclusions

Genetic risk for reproducing a PSS in Irish Wolfhounds was accurate, using the described method.

Clinical Relevance

Risk estimation provides a tool for genetic counseling, does not require knowledge of the mode of inheritance, and may be valid for any inherited disease. (Am J Vet Res 1998;59:1553-1556)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To analyze familial clustering and genetic risk for various forms of elbow dysplasia (ED) in Bernese Mountain Dogs (BMD) in The Netherlands and define possible means to select against ED.

Animals

98 BMD born in 1992 and 64 BMD born in 1995.

Procedure

Dogs were examined radiographically when 12 to 18 months old. The population was resolved into familial clusters, and distribution of ED for the clusters was analyzed. Common ancestors associated with each form of ED were identified, and risk for having ED in the 64 offspring born in 1995 was calculated by relatedness to common ancestors. Risk was compared with radiographic outcome.

Results

The 2 forms of ED identified were fragmented coronoid process (FCP) and elbow joint incongruity (INC). Incidence of ED decreased from 63/98 (64%) in 1992 to 29/64 (45%) in 1995. None of the familial clusters was free of FCP or INC. Common ancestors associated with FCP differed from those associated with INC. There was more potential variation in risk for FCP and INC in the 64 offspring than was achieved by breeders, indicating a decrease in population heterogeneity.

Conclusions and Clinical Relevance

FCP and INC had differing familial sources; thus, they most likely are different genetic traits. Although Incidence of ED decreased from 1992 through 1995, we did not detect variation among pedigrees in genetic risk for ED remaining in the offspring born in 1995; thus, selection among families cannot further improve ED health status of BMD in The Netherlands. Phenotypic selection within families remains the only alternative. [Am J Vet Res 1999;60:1082-1087)

Free access
in American Journal of Veterinary Research