GWAS reveals determinants of mobilization rate and dynamics of an active endogenous retrovirus of cattle.

Five to ten percent of mammalian genomes is occupied by multiple clades of endogenous retroviruses (ERVs), that may count thousands of members. New ERV clades arise by retroviral infection of the germline followed by expansion by reinfection and/or retrotransposition. ERV mobilization is a source of deleterious variation, driving the emergence of ERV silencing mechanisms, leaving "DNA fossils". Here we show that the ERVK[2-1-LTR] clade is still active in the bovine and a source of disease-causing alleles. We develop a method to measure the rate of ERVK[2-1-LTR] mobilization, finding an average of 1 per ~150 sperm cells, with >10-fold difference between animals. We perform a genome-wide association study and identify eight loci affecting ERVK[2-1-LTR] mobilization. We provide evidence that polymorphic ERVK[2-1-LTR] elements in four of these loci cause the association. We generate a catalogue of full length ERVK[2-1-LTR] elements, and show that it comprises 15% of C-type autonomous elements, and 85% of D-type non-autonomous elements lacking functional genes. We show that >25% of the variance of mobilization rate is determined by the number of C-type elements, yet that de novo insertions are dominated by D-type elements. We propose that D-type elements act as parasite-of-parasite gene drives that may contribute to the observed demise of ERV elements.

Description of Plasma Penicillin G Concentrations after Intramuscular Injection in Double-Muscled Cows to Optimize the Timing of Antibiotherapy for Caesarean Section.

In order to improve the efficacy of penicillin injection during caesarean section, we aimed to identify the optimal timing of its preoperative administration. A study was conducted in 12 adult, non-pregnant Belgian Blue cows. To evaluate the plasma penicillin concentrations, blood samples were taken from the jugular vein at -5, 15, 30, 45, 60, 120, 240, 480 min relative to the intramuscular (IM) injection of 21,000 IU/kg of body weight of penicillin G. Results showed that plasma concentrations at 15 min after IM injection (668.3 ± 73.7 ng/mL) largely exceeded the minimal inhibitory concentration (MIC) of penicillin-sensitive bacteria (MIC < 125 ng/mL). With increasing time, plasma concentrations continued to rise, attaining an increasing proportion of moderately sensitive bacteria (250 ng/mL > MIC < 2000 ng/mL). The maximal concentration was reached between 1 and 4 h (average: 1.495.1 ± 181.7 ng/mL) after IM injection in the majority of cows, and decreased non-significantly to 1002.1 ± 93.2 ng/mL at 8 h. In conclusion, plasma penicillin concentrations at 15 min after an IM injection inhibit penicillin-sensitive bacteria. However, in order to obtain the maximal protective effect of the antibiotherapy, surgery should be started at 1 to 2 h after IM penicillin injection.

Parietal fibrinous peritonitis in cattle: A literature review.

BACKGROUND: Parietal fibrinous peritonitis (PFP) is a complication of laparotomy in cattle, consisting of fluid and fibrin accumulation within a fibrous capsule between the parietal peritoneum and the abdominal muscles. Since scientific information on PFP is scarce, we aim to collect available information to help practitioners in its diagnosis and treatment, and to formulate research perspectives. METHODS: PubMed and GoogleScholar databases were scanned using "cattle" or "bovine", and one of the following keywords: "seroma", "parietal fibrinous peritonitis", "retroperitoneal abscess", or "wound infection". RESULTS: Although scientific information is often anecdotal, two recent larger studies shed more light on PFP symptoms, diagnosis and treatment. Symptoms vary according to the cavity's localisation and size, and include anorexia, weight loss and an inflammatory status. Rectal palpation is strongly indicative, but the definitive diagnosis is made by ultrasound. Trueperella pyogenes and Escherichia coli are frequently isolated germs, although it remains unclear whether they are primary or secondary agents. Good survival rates were reported after surgical drainage. CONCLUSION: Although the diagnosis and treatment seem clear, the exact pathogenesis of PFP should be the focus of ongoing research. This can be achieved by epidemiological data analysis focusing on risk factors like surgery technique, housing and ration.

Prophylactic antibiotic usage by Belgian veterinarians during elective caesarean section in Belgian blue cattle.

The use of prophylactic antibiotics in veterinary surgery reduces the occurrence of postoperative complications. In order to limit the development of antimicrobial resistance in bacteria and to maximize therapy efficacy, antibiotics should be used prudently and efficiently. A survey was sent to Wallonian rural veterinarians in order to assess the use of antibiotics before, during and after bovine elective caesarean section, the most common surgical procedure in Belgian rural practice. Results were analysed in the light of the current guidelines formulated by the Belgian Centre of Expertise on Antimicrobial Consumption and Resistance in Animals. Among 380 contacted veterinarians, 113 answered the survey. All veterinarians use antibiotics during caesarean section. Veterinarians predominantly use penicillin as the first drug of choice, whereas a minority use drugs considered as second or third choice, such as amoxicillin, oxytetracyclin or lincomycin-spectinomycin. Also, 31/113 veterinarians simultaneously use molecules from different antibiotic classes. The majority (100/113) of veterinarians inject antibiotics during or after surgery, while a minority (13/113) administer antibiotics preoperatively. Most veterinarians (67/113) limit the duration of their antibiotic treatment to 1 day. Considering the administration route, most veterinarians (88/113) systematically use the intraperitoneal injection route, which is not registered. Intramuscular injection and injection between muscle layers during surgery are carried out by 82/113 and 43/113 respondents, respectively. Twenty-two respondents apply intra-uterine antibiotics. Most veterinarians (87/113) combine several administration routes. The dosage of antibiotics varies enormously and excessive injection volumes are common, especially when multiple injection routes are combined. Our results show a striking lack of consistency in the antibiotic therapy during elective CS by rural veterinarians. Whereas the drug of choice and the treatment duration were largely in line with the current guidelines, this is certainly not the case for the dosage and the administration route. The intraperitoneal injection of antibiotics cannot be justified. Incorrect dosage of antibiotics should be avoided at all cost. The use of second and third line molecules and the simultaneous use of different antibiotic classes should be discouraged. A major challenge lies in the education of veterinary students and the sensitization of practitioners to avoid or unlearn unnecessary habits concerning antibiotic use. Finally, more clinical trials are needed in order to refine the current guidelines for antibiotic use and to determine the optimal drug of choice, treatment moment and application route in elective caesarean section in cattle.

Natural intrauterine infection with Schmallenberg virus in malformed newborn calves.

We surveyed morphologic alterations in calves in Belgium that were naturally infected in utero by Schmallenberg virus (SBV) and born with deformities during January-March 2012. SBV-specific RNA was distributed unevenly in different tissues. Natural intrauterine SBV infection of calves might cause serious damage to the central nervous system and muscles.

A missense mutation accelerating the gating of the lysosomal Cl-/H+-exchanger ClC-7/Ostm1 causes osteopetrosis with gingival hamartomas in cattle.

Chloride-proton exchange by the lysosomal anion transporter ClC-7/Ostm1 is of pivotal importance for the physiology of lysosomes and bone resorption. Mice lacking either ClC-7 or Ostm1 develop a lysosomal storage disease and mutations in either protein have been found to underlie osteopetrosis in mice and humans. Some human disease-causing CLCN7 mutations accelerate the usually slow voltage-dependent gating of ClC-7/Ostm1. However, it has remained unclear whether the fastened kinetics is indeed causative for the disease. Here we identified and characterized a new deleterious ClC-7 mutation in Belgian Blue cattle with a severe symptomatology including perinatal lethality and in most cases gingival hamartomas. By autozygosity mapping and genome-wide sequencing we found a handful of candidate variants, including a cluster of three private SNPs causing the substitution of a conserved tyrosine in the CBS2 domain of ClC-7 by glutamine. The case for ClC-7 was strengthened by subsequent examination of affected calves that revealed severe osteopetrosis. The Y750Q mutation largely preserved the lysosomal localization and assembly of ClC-7/Ostm1, but drastically accelerated its activation by membrane depolarization. These data provide first evidence that accelerated ClC-7/Ostm1 gating per se is deleterious, highlighting a physiological importance of the slow voltage-activation of ClC-7/Ostm1 in lysosomal function and bone resorption.