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Diarrhoea is a leading cause of calf mortality in US cattle herds, resulting in significant economic losses to cattle producers. Calves with diarrhoea are often <1 month of age. Infectious causes of calf diarrhoea include viral, bacterial and protozoal pathogens. Diagnostic tests are routinely utilized for detection of common viruses such as bovine rotavirus (BRV), bovine coronavirus (BCoV) and bovine viral diarrhoea virus (BVDV). However, a review of laboratory test results generated between 1 January 2016 and 21 August 2019 at the University of Illinois Veterinary Diagnostic Laboratory (VDL) showed that these three viruses (BRV, BCoV and BVDV) were detected in approximately 30% of calves with diarrhoea, including animals with histopathology changes that were suggestive of viral involvement. These results suggest that other unidentified viral pathogens may be involved in calf diarrhoea. Recently, we reported identification of bovine kobuvirus (BKV) in diarrhoeic calves in the United States and added evidence that BKV might be associated with diarrhoea in cattle (Wang et al., 2020). Herein, we review taxonomy and genome organization, detection of BKV in different countries and genomic characterization.

We presented an antibiotic-loaded c-cyclodextrin metal-organic framework that delivered antibiotics suitable for the treatment of bacterial infections. The c-cyclodextrin metal-organic framework was developed using c-cyclodextrin and potassium ion via the ultrasonic method. The antibiotic (florfenicol and enrofloxacin) was primarily encapsulated into the pore structures of c-CD-MOF, which allowed the sustained release of antibiotics over an extended period of time in vitro and in vivo. Notably, antibiotics-loaded c-CD-MOF showed much superior activity against bacteria than free antibiotics (lower MIC value) and displayed better long-lasting activity (longer antibacterial time). The antibiotics-loaded c-CD-MOF showed nontoxic and perfect biocompatibility to mammalian cells and tissues both in vitro and in vivo. These materials thus represent a novel drug-delivery device suitable for antibiotic therapy. This research is of great significance for reducing the generation of bacterial resistance and providing new ideas for the application of c-CD-MOF.

The objective of this study was to evaluate the effects of dietary inclusion of tevioside on feed intake, feeding behavior, nutrient digestion, rumen fermentation, and serum biochemical parameters in goats. Nine male Xiangdong black goats (21.8 ± 1.5 kg of body weight) were used in a replicated 3 × 3 Latin square. All goats were fed a basal diet including concentrate and forage (chopped rice traw). The three treatments were 0, 400, or 800 mg stevioside per kg chopped rice traw on a dry matter (DM) basis. Dry matter intake of forage and total diet linearly increased (p = 0.03 and p = 0.04) with increasing stevioside in the diet. There was no effect (p > 0.05) of stevioside inclusion in the diets on eating time, rumination time, or total mastication time for the goats. Total volatile fatty acid (VFA) concentration in the rumen responded quadratically (p < 0.01), decreasing from 0 to 400 mg/kg stevioside inclusion and increasing thereafter. The inclusion of steviosid in the diets promoted a quadratic increase in the apparent total tract digestibilities of neutral detergent fiber (NDF) (p = 0.02) and acid detergent fiber (ADF) (p = 0.01). Based on the results of this experiment, it could be concluded that supplementing goat diets with stevioside at 400 mg/kg to 800 mg/kg forage (about 270 to 541 mg/kg diet) resulted in increased dry intake of forage and total diet, suggesting that stevioside has positive potential as a feed additive to improve feed intake.