Long term outcome after surgical correction of mandibular brachygnathia with unilateral type 1 external skeletal fixation.

OBJECTIVE: To describe complications and long-term outcome after surgical correction of severe overbite in 7 horses using corrective osteotomy and a Type I external fixator. STUDY DESIGN: Case series. ANIMALS: Horses (n = 7). METHODS: Seven horses with severe mandibular brachygnathia were treated by corrective osteotomy and a Type I external fixator. Data on surgical technique, complications, long-term outcome and owner satisfaction were recorded. RESULTS: Severe mandibular brachygnathia was corrected successfully in all horses. Short term follow-up revealed a relatively high morbidity due to several complications such as surgical site infection, sequestrum formation and instability due to early pin loosening. Long-term over all owner satisfaction was very high. CONCLUSIONS: Corrective osteotomy and fixation with an external fixator is an effective surgical technique for correction of severe mandibular brachygnathia and offers good results in a long-term perspective.

Evaluation of the influences of exercise, birth date, and osteochondrosis on plasma bone marker concentrations in Hanoverian Warmblood foals.

OBJECTIVE: To determine whether plasma concentrations of bone turnover markers in growing Hanoverian foals are influenced by age, housing conditions, or osteochondrosis. ANIMALS: 165 healthy foals and 119 foals with osteochondrosis. PROCEDURES: Foals were allocated according to birth date and housing management into groups of early-born (born before March 31, 2001; n = 154 foals, 88 of which were healthy and 66 of which had osteochondrosis) and late-born (born after March 31, 2001; 130 foals, 77 of which were healthy and 53 of which had osteochondrosis) foals. Plasma osteocalcin and carboxyterminal propeptide of type I collagen concentrations were analyzed as markers of bone formation, and carboxyterminal telopeptide of type I collagen concentration was analyzed as a marker of bone resorption. Foals underwent radiographic evaluation to screen for osteochondrosis. RESULTS: Plasma concentrations of osteocalcin, carboxyterminal propeptide of type I collagen, and carboxyterminal telopeptide of type I collagen decreased with age, but these changes were more distinct in late-born foals than in early-born foals. Neither sex nor predisposition to develop osteochondrosis affected the pattern of bone marker changes in either group. CONCLUSIONS AND CLINICAL RELEVANCE: An age-related decrease in concentrations of bone markers was seen during the first 200 days of life. Changes in bone marker concentrations were similar for foals with osteochondrosis and healthy foals. The correlation between the decrease in bone marker concentration and date of birth indicates that there are differences in skeletal development between early- and late-born foals.

Genome-wide search for microsatellite markers associated with radiologic alterations in the navicular bone of Hanoverian warmblood horses.

The aim of this study was to identify quantitative trait loci (QTLs) for pathologic changes in the navicular bone in Hanoverian warmblood horses. Seventeen paternal half-sib groups comprising 192 individuals were analyzed in a whole-genome scan. These families included 144 progeny and grandchildren, which were randomly chosen from the Hanoverian warmblood. Three different traits were considered: deformed canales sesamoidales and radiographic changes in the contour and in the structure of the navicular bone. The genome scan included in total 214 highly polymorphic microsatellite markers. The putatively linked genomic regions on equine chromosomes (ECA) 2, 3, 10, and 15 were refined using 53 additional microsatellites. Chromosome-wide significant QTLs were located on five different equine chromosomes (ECA2, 3, 4, 10, and 26). Genome-wide significant QTLs were on ECA2 at 48 cM and on ECA10 from 45.5 to 49.8 cM. This study was a first step to get more insight into the molecular genetic determination of radiologic changes in the equine navicular bone.