Year: 2013
Type: dissertation
Abstract: Screening in dog breeding refers to testing or examining individuals for hereditary diseases or faults. Results can help dog breeders in decision-making when selecting breeding material. Radiographic screening for canine elbow dysplasia (ED) began several decades ago, but genetic improvements have been modest. Several reasons for slow progress exist; perhaps one of the most important is that affected individuals continue to be used for breeding. On the other hand, disorders like lumbosacral transitional vertebrae (LTV) in several dog breeds and intervertebral disc calcifications in Dachshunds are not widely screened even though this would reduce the incidence of debilitating orthopaedic and neurological diseases caused by these disorders. The aim of this study was to initiate radiographic screening protocols for intervertebral disc calcifications and LTV in Finland and to revise the existing Finnish screening protocol for ED. Breeds used were the miniature long-haired and wire-haired Dachshund, Belgian shepherd dog, Labrador retriever and German shepherd dog. The imaging methods applied were radiography and computed tomography (CT). Occurrence of intervertebral disc calcifications was higher in Finnish miniature Dachshunds than previously reported; 76% of longhaired and 87% of wirehaired variety had at least one calcification. Therefore screening protocol excluding every dog with calcifications from breeding would not be possible. The number of calcifications varied between none and 13, and therefore radiographic screening, together with favouring dogs with fewer calcified discs in breeding, is suggested. Accuracy of the Finnish screening protocol for mild (grade 1) ED differed between the two breeds studied. In Belgian shepherd dogs, the Finnish protocol based mainly on evaluation of osteophytes was inaccurate, as 47% of the joints free of ED were incorrectly graded as dysplastic and 40% of dysplastic joints were graded as normal. On the other hand, assessment of the radiographic signs indicative of medial coronoid process disease proved to be accurate in this breed; sensitivity and specificity of blurring of the cranial border of the medial coronoid process were 80% and 90%, respectively. In Labrador retrievers, the Finnish protocol proved to be accurate, as sensitivity of grading was 79% and specificity 92%. Osteophytes seen in the supplemental craniocaudal oblique radiographic projection was the most reliable sign of ED in Labrador retrievers with sensitivity of 93% and specificity of 92%. Adding this view might be a valuable addition to the screening protocol. Labrador retrievers with grade 1 ED should not be used for breeding since most of them have ED, as was clearly demonstrated in the study. LTV was common in Finnish German shepherd dogs studied with occurrence of 40%. A laterolateral (LL) radiograph appeared to be a useful supplement to the currently used ventrodorsal (VD) radiograph in diagnosis of LTV. Sensitivity of the diagnosis based on the VD projection alone was 90% increasing to 100% when LL projection was used together with the VD projection. Additionally, diagnosis of the eighth lumbar vertebra (L8) was only possible based on the LL projection. It is therefore suggested for inclusion in the radiographic screening protocol. The L8 resembled an LTV, and is therefore proposed as a part of the LTV-complex and for consideration when screening for LTV.
Source: Työväentutkimus Vuosikirja
Author: Anu K. Lappalainen
Language: English
Subfield: Small Animals
Field: Veterinary
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2155624263