Genetic variances due to imprinted genes in cattle

The effect of paternally expressed, i.e. maternally imprinted, genes on slaughter records from 2744 German Gelbvieh finishing bulls were estimated. Significant effects of paternal gametes were found for two fatness traits and an estimate of meat content. Paternally expressed genes explained 14 and 16% of the phenotypic variances for pelvic fat and kidney fat, respectively. Ignoring paternal gametic effects resulted in inflated estimates of the additive genetic variances. The heritabilities of pelvic and kidney fat dropped from 0.31 to 0.16 and from 0.59 to 0.28, respectively, when paternal gametes were fitted. A 15% influence of paternally expressed genes and a reduction in heritability of 20% were also found for estimated meat content. Simulation studies demonstrated that the uncorrelated random effect of the sire is a useful indicator for the presence of paternal gametic effects in variance component estimations. The presented results correspond well with findings in swine, where a paternally expressed QTL at the Igf2 gene influences similar trait complexes. A viable speculation could therefore be that an imprinted bovine Igf2 gene caused the effects described here.     

Treatment of Age‐Related Hearing Loss in Dogs with the Vibrant Soundbridge Middle Ear Implant: Short‐Term Results in 3 Dogs

Background: Age‐related hearing loss (ARHL), or presbycusis, is the most common form of acquired hearing loss in dogs. Middle ear implants have been used successfully in people with ARHL who cannot benefit from conventional hearing aids. Hypothesis: Audibility improves in dogs with ARHL after implantation of the Vibrant Soundbridge (VSB) middle ear implant. Animals: Three Beagle dogs with ARHL, mean age 11.1 years. Methods: The dogs were assessed pre‐ and postoperatively by brainstem‐evoked response audiometry (BERA), otoscopy, and computed tomography scans of the ears. A VSB middle ear implant was implanted unilaterally. Three months later the functionality of the implants was assessed by auditory steady‐state responses (ASSRs), after which the dogs were euthanized for histopathological examination. Results: The VSB was implanted successfully in all dogs. Recovery from surgery was uneventful, except for transient facial nerve paralysis in 2 dogs. ASSRs showed that hearing improved after activation of the implants with a mean of 20.7, 13, and 16.3 dB at 1, 2, and 4 kHz, respectively. The implantation procedure did not affect residual hearing (with inactive implants) as measured by BERA. Conclusions and Clinical Importance: Implantation of the VSB resulted in lower ASSR thresholds, but only at the higher gain settings of the audioprocessor. As in humans, a more powerful audioprocessor is required to treat sensorineural hearing loss exceeding 20 dB in dogs. A substantial improvement in patient‐owner communication will have to be demonstrated in future studies before the procedure can be recommended in clinical practice.     

GENDER,WEIGHT, AND AGE EFFECTS ON PREVALENCE OF CAUDAL ABERRANT NASAL TURBINATES IN CLINICALLY HEALTHY ENGLISH BULLDOGS: A COMPUTED TOMOGRAPHIC STUDY AND CLASSIFICATION

English Bulldogs have been reported to demonstrate abnormal growth and development of the nasal turbinates, which contribute to an increase in airway resistance and hence clinical signs of brachycephalic airway syndrome. The purpose of this prospective, cross‐sectional study was to assess the prevalence and severity of caudal aberrant turbinate protrusion via CT studies of English Bulldogs with, according to the owners, none or minimal clinical signs of brachycephalic airway syndrome. An additional objective was to propose a classification scheme for describing the degree of caudal aberrant turbinate protrusion in English Bulldogs and to apply this scheme in assessing the effect of gender, weight, and age on prevalence and severity of turbinate protrusion. The nasal cavities of 40 clinically healthy English Bulldogs were examined. The prevalence of caudal aberrant turbinates in this group was 100%. Using our proposed classification scheme, Grade 1 (minimal) was detected in 7 of 40 (17.5%), Grade 2 (mild) in 28 of 40 (70%), and Grade 3 (moderate) in 5 of 40 (12.5%) English Bulldogs. No significant effect of gender, weight, and age on degree of protrusion was found. In conclusion, this study identified minimal to moderate protrusion of caudal aberrant turbinates toward the nasopharynx in all the sampled English Bulldogs, despite the absence of clinical signs of brachycephalic airway syndrome.