Detailed analysis of mortality rates in the female progeny of 1,001 Holstein bulls allows the discovery of new dominant genetic defects.

Reducing juvenile mortality in cattle is important for both economic and animal welfare reasons. Previous studies have revealed a large variability in mortality rates between breeds and sire progeny groups, with some extreme cases due to dominant mutations causing various syndromes among the descendants of mosaic bulls. The purpose of this study was to monitor sire-family calf mortality within the French and Walloon Holstein populations, and to use this information to detect genetic defects that might have been overlooked by lack of specific symptoms. In a population of heifers born from 1,001 bulls between 2017 and 2020, the average sire-family mortality rates were of 11.8% from birth to 1 year of age and of 4.2, 2.9, 3.1, and 3.2% for the perinatal, postnatal, preweaning, and postweaning subperiods, respectively. After outlining the 5 worst bulls per category, we paid particular attention to the bulls Mo and Pa, because they were half-brothers. Using a battery of approaches, including necropsies, karyotyping, genetic mapping, and whole-genome sequencing, we described 2 new independent genetic defects in their progeny and their molecular etiology. Mo was found to carry a de novo reciprocal translocation between chromosomes BTA26 and BTA29, leading to increased embryonic and juvenile mortality because of aneuploidy. Clinical examination of 2 calves that were monosomic for a large proportion of BTA29, including an orthologous segment deleted in human Jacobsen syndrome, revealed symptoms shared between species. In contrast, Pa was found to be mosaic for a dominant de novo nonsense mutation of GATA 6 binding protein (GATA6), causing severe cardiac malformations. In conclusion, our results highlight the power of monitoring juvenile mortality to identify dominant genetic defects due to de novo mutation events.

A large outbreak of bovine botulism possibly linked to a massive contamination of grass silage by type D/C Clostridium botulinum spores on a farm with dairy and poultry operations.

Type D bovine botulism outbreaks associated with poultry litter are increasingly reported in European countries, but the circumstances of exposure to Clostridium botulinum toxins remain unclear. In spring 2015, a large type D/C bovine botulism outbreak affected a farm with dairy and poultry operations. Epidemiological and laboratory investigations strongly suggest that the outbreak was caused by feeding cattle with insufficiently acidified grass silage that was contaminated by type D/C C. botulinum spores. The source of the spores remains unclear, but could have been a stack of poultry litter stored in the grass silage pasture before harvesting. The presence of putrefied poultry carcasses mixed in with the litter is relatively unlikely considering the careful daily removal of poultry carcasses. These findings reinforce the importance of proper ensiling of feed materials and highlight the need for safe disposal of poultry litter, even in the case of good management of poultry deadstock, in order to prevent bovine botulism.

Aminoaciduria Caused by Fanconi Syndrome in a Heifer.

A case study of renal tubular dysfunction consistent with idiopathic Fanconi syndrome is reported in an 18-month-old Holstein heifer. The clinical, biochemical, and histopathological features are described. The heifer had clinical signs of growth retardation, wasting, and persistent diarrhea. Biochemical blood analysis identified hypokalemia, hyponatremia, and hypochloremia. Urinalysis identified glycosuria, proteinuria, and acidic pH. Histological examination of the kidney disclosed mild tubular necrosis with proteinaceous casts in the lumina of renal tubules. We performed LC-HRMS on urine to confirm Fanconi syndrome. Using this technique, we identified severe generalized aminoaciduria suggestive of idiopathic renal Fanconi syndrome in this heifer.

High-grade mucoepidermoid carcinoma of the mandibular salivary gland in a lion (Panthera leo).

A 13-year-old neutered male lion was presented with a primary neoplasm arising from the left mandibular salivary gland associated with metastases to regional lymph nodes, thoracic viscera (lungs, heart, esophagus, and diaphragm), and kidney. Histologic and immunohistochemical investigations led to a diagnosis of a high-grade mucoepidermoid carcinoma of the mandibular salivary gland. In this case report, we point out the importance of the immunohistochemical characterization for differential diagnosis between various types of carcinomas of the salivary gland.