Clostridioides difficile on Ohio swine farms (2015): A comparison of swine and human environments and assessment of on‐farm risk factors

Swine are known reservoirs for Clostridioides difficile, formerly known as Clostridium difficile, and transmission from swine to human farm workers is strongly suggested by previous studies. This cross‐sectional study evaluated the potential role of farm environmental surfaces, including those in worker breakrooms and swine housing areas, in the possible transmission of C. difficile from swine to farm workers. Environmental surfaces and piglet faeces at 13 Ohio swine farms were sampled in 2015. Typical culturing techniques were performed to isolate C. difficile from samples, and amplification of toxin genes (tcdA, tcdB and cdtB) and PCR‐ribotyping were used to genetically characterize recovered isolates. In addition, sequencing of toxin regulatory gene, tcdC, was done to identify the length of identified deletions in some isolates. A survey collected farm‐level management risk factor information. Clostridioides difficile was recovered from all farms, with 42% (188/445) of samples testing positive for C. difficile. Samples collected from all on‐farm locations recovered C. difficile, including farrowing rooms (60%, 107/178), breakrooms (50%, 69/138) and nursery rooms (9%, 12/129). Three ribotypes recovered from both swine and human environments (078, 412 and 005) have been previously implicated in human disease. Samples taken from farrowing rooms and breakrooms were found to have greater odds of C. difficile recovery than those taken from nursery rooms (OR = 40.5, OR = 35.6, p < .001 respectively). Farms that weaned ≥23,500 pigs per year had lower odds of C. difficile recovery as compared to farms that weaned fewer pigs (OR = 0.4, p = .01) and weekly or more frequent cleaning of breakroom counters was associated with higher odds of C. difficile recovery (OR = 11.7, p < .001). This study provides important insights into the presence and characterization of C. difficile found in human environments on swine farms and highlights how these areas may be involved in transmission of C. difficile to swine farm workers and throughout the facility.     

Bodyweight and feed intake of German shepherd bitches during pregnancy and lactation

Thirty German shepherd bitches were assessed for weekly changes in bodyweight, daily food intake and litter size during pregnancy and lactation. The weekly changes in food intake and bodyweight were divided into two and three phases, respectively. Linear regression equations were used to fit each phase. The bodyweight of the bitches at mating ranged between 17 and 36 kg. The same diet was used for all the bitches throughout the study. Despite the tendency that litter size, birthweight and bodyweight of the puppies at three and six weeks increased with age of the bitch, no significant differences could be found. Significant (P<0·05) bodyweight differences existed at mating between the age groups. High correlations existed between mating weight and weight at 60 days of pregnancy (r²= 0·94] and between mating weight and weaning weight (r²= 0·89) of the litter. It was possible to successfully establish performance criteria for the reproductive German shepherd bitch in a commercial breeding unit, which can be used as a baseline to improve diets and feeding programmes by means of dietary manipulations.     

Central Venous Pressure Measurements in the Caudal Vena Cava of Sedated Cats

The caudla vena cava (CVA) was evaluated as an laternative site for the measurement of central venous pressure (CPV) in six healthy, sedated (ketamine 10 mg/km, midazolam 0.1 mg/kg, and atropine 0.04 mg/kg IM) cats. The CVC was cathererized via medial saphenous puncture, and estimates of CPV from this site compared to those obtained via a jugular catheter. Simulataneous CPV values were recorded electronically (mmgh), via calibrated pressure transducer positioned at the level of the manubrium in cats in lateral recumbency. Five readings, performed at 1 minute intervals, were collected from the jugular and CVC catheters at rest (baseline) and following a rapid fluid bolus. Twenty-four hours later, cats were resedated, baseline measurements repeated, and CVPs recorded following a rapid, 25% whole-blood volume bleed. CVP measurements from the jugular and CVC were statistically compared using repeated measures ANOVA (p<0.05). There were no significant differences between the two sites in the baseline and bleed trials. Significant defferences between jugular and CVC CVPs were noted at 1 and 2 minutes following the fluid bolus. It was concluded that CVC is an alternative site for measurement of CPV in sedated cats.     

Identification of tissue hypoxia in the livers of ascitic and hypoxia‐induced broilers using trypan blue

1. The perfusion of livers with the vital dye trypan blue was performed to test for evidence of tissue hypoxia in 3 groups of young broiler chickens, namely, ascitic, hypoxia‐induced and controls.

2. Hepatocytes that stained with trypan blue were considered to be dead or dying before fixation and represented damaged cells.

3. The proportion of trypan blue‐stained hepatocytes in the livers of ascitic birds was slightly less than half that observed in the hypoxia‐induced birds but significandy more than the proportion of stained cells observed in control birds.

4. Liver damage in the ascitic birds was also assessed biochemically by an altered enzyme profile.

5. The study demonstrated that increased trypan blue uptake in the livers of ascitic birds reared at sea‐level may be the consequence of hypoxia stress caused by reduced oxygen utilisation.     

The impact of Theileria parva infections and other factors on calf mean daily weight gains in smallholder dairy farms in Murang'a District, Kenya

The association between mean daily weight gain, Theileria parva infections, clinical East Coast fever and other possible determinants of weight gain were examined in a longitudinal observational study that was conducted in cohorts of female calves from five agro-ecological zone (AEZ)-grazing strata. The strata were upper-midlands (UM) 1 zero-grazing, UM 1 open-grazing, UM 2 zero-grazing, UM 4 zero-grazing and UM 4 open-grazing. In total, 225 calves on 188 smallholder dairy farms were visited within the first 2 weeks of life and thereafter at biweekly intervals up to the age of 6 months between March 1995 and August 1996. During each visit, the calves were weighed and other calf-management practices in the farm during the visit such as housing, feeding and tick control also were recorded. Other events such as morbidity and mortality between or during the visits were also recorded.

The overall mean daily weight gains were 0.24–0.29 kg (S.D.=0.17–0.22 kg) and were lower than the recommended targets for smallholder farms of 0.40–0.50 kg. The major tendency in variability of daily weight gains was due to visit-to-visit variation (especially in calves >3 months old).

Differences in mean daily gains were associated with AEZ-grazing strata and calf-level factors that included breed of calf, calf sickness, incidence of ECF, feeding of milk, concentrate feeds and minerals and interaction between calf age and AEZ-grazing strata (P<0.05). ECF and other calf sicknesses exerted a temporal effect on calf-growth at the height of illness and immediately after; calves later recovered the lost growth except where other factors such as poor calf nutrition prevailed. Improvement in calf-growth in Murang’a District is achievable and extension services should continue to target individual-calf-level management practices.     

Experimental Mycotoxic Nephropathy in Pigs Provoked by a Diet Containing Ochratoxin A and Penicillic Acid

Mycotoxic nephropathy was induced in 18 young pigs by diets contaminated with strains of Aspergillus ochraceus containing ochratoxin A (OTA) and penicillic acid (PA) at levels corresponding to those naturally encountered in animal feeds in Bulgaria. Haematological and biochemical parameters, as well as the morphological and ultrastructural changes in various internal organs, and especially in the kidneys, were examined at different stages of development of the disease. A mottled surface of the kidneys was only seen in pigs exposed to a mouldy diet containing 180 ppb OTA for 3 months, but microscopic lesions, as well as changes in various haematological and biochemical parameters, were observed in all groups exposed to the same mouldy diet containing only 90 or 180 ppb OTA. Histological examination showed two types of change: degenerative changes affecting the epithelial cells of the proximal tubules, which predominated at the initial stage, and proliferative changes in the interstitium, which predominated at the later stage of the disease. Telangiectasis and lymph stasis were also seen, as well as degenerative changes in the capillary endothelium. The characteristic renal lesions were similar to those observed in spontaneous cases of mycotoxic porcine nephropathy in Bulgaria, but they were a little different from the classic Danish porcine nephropathy. The enhanced toxicity of OTA in our study may be due to a synergistic effect between OTA and PA or to some other unknown metabolites produced by the same ochratoxinogenic strains of A. ochraceus.