D-lactate production and excretion in diarrheic calves

The origin of D-lactate, the most important acid contributing to metabolic acidosis in the diarrheic calf, is unknown. We hypothesized that because D-lactate is produced only by microbes, gastrointestinal fermentation is the source. The objective of this study was to determine whether D-lactate production occurs in the rumen, colon, or both, and to measure D- and L-lactate concentrations in urine. Fecal, rumen, blood, and urine samples were obtained from 16 diarrheic and 11 healthy calves. Serum electrolyte concentrations were measured in both groups, and blood gas analyses were performed for diarrheic calves. All samples were analyzed for D- and L-lactate by high performance liquid chromatography (HPLC). Diarrheic calves were generally hyperkalemic with high serum anion gap, depressed serum bicarbonate, and low blood pH. L-lactate was markedly higher in rumen contents (22.7 mmol/ L [median]) and feces (8.6 mmol/L) of diarrheic calves than healthy calves (0.5 mmol/L and 5.1 mmol/L, respectively), but not different in serum or urine. Rumen, fecal, serum, and urine D-lactate concentrations were all significantly higher (P < .05) in diarrheic calves (17.0, 25.4, 13.9, and 19.2 mmol/L, respectively) than in healthy calves (0.5, 9.1, 1.4, and 0.5 mmol/L, respectively). Higher D-lactate concentrations in the rumen and feces of diarrheic calves suggests these sites as the source of D-lactate in blood and urine.     

Immunoperoxidase study of adenovirus pneumonia in dogs

Summary

The pathology of adenovirus pneumonia in 16 dogs is described. Clinically, these dogs had been severely ill, with severe dyspnoea and listlessness, but only faint coughing.

Histopathological lesions could be associated directly with the presence of adenovirus antigens in the lungs of these dogs by using an unlabelled immunoperoxidase technique on paraffin tissue sections. The lesions were focal and located in alveoli and bronchioles. Infected cells were mostly alveolar macrophages and less frequently type I and 2 pneumocytes and bronchiolar epithelial cells. Infiltrating neutrophils and lymphocytes were not observed to be infected.

This type of pneumonia appears to be a fairly well defined clinical and pathological entity in kennel dogs.     

Effects of intensification of pastoral farming on greenhouse gas emissions in New Zealand

Abstract

AIMS: The aims of this cross-sectional study were to investigate the herd and cow-level prevalence of bovine digital dermatitis (BDD) in dairy farms in the northern Taranaki region of New Zealand, and to identify whether there was any spatial clustering of herds with the disease.

METHODS: A survey of 224 dairy farms in the northern Taranaki region of New Zealand was undertaken from September 2014 to February 2015. Following training in robust criteria to confirm BDD visually, a technician inspected the rear feet of every milking cow on the farms during milking. The identity of cows with lesions and the feet involved were recorded. The proportion of cows affected among the inspected population (cow-level prevalence), the proportion of a herd affected (farm-level prevalence), and proportion of farms with ≥1 cow with lesions, were calculated. A bivariate K function analysis was then used to assess whether farms with ≥1 cow with lesions were clustered, after accounting for the distribution of the farms involved in the study.

RESULTS: Bovine digital dermatitis lesions were observed on 143/224 (63.8 (95% CI=57.5–70.1)%) farms. Within-farm prevalence was 0% on 81 (36.2%) farms, between >0 and <3% on 120 (53.5%) farms, with a maximum prevalence of 12.7% on one farm. Overall, cow-level prevalence was 707/60,455 (1.2 (95% CI=0.9–3.0)%), and on affected farms was 707/41,116 (1.7 (95% CI=1.4–2.1)%). In affected cows, 268/707 (37.9%) had a lesion on left foot only, 262/707 (37.1%) on the right foot only and 177/707 (25.0%) on both feet. The K function analysis showed no evidence of clustering of farms with BDD.

CONCLUSIONS: Bovine digital dermatitis was widespread among the survey farms, but there was no evidence that there was any clustering of herds with BDD. The cow-level prevalence on affected farms was much lower than reported elsewhere.

CLINICAL RELEVANCE: Although the prevalence at the cow level was low, if these data are representative of other regions of New Zealand, BDD could easily become a major problem on dairy farms in New Zealand, as has been observed in other countries.     

Reconstructing past ocean pH-depth profiles

Measurement of boron isotope compositions in species of planktonic foraminifera that calcified their tests at different depths in the water column are used to reconstruct the pH profile of the upper water column of the tropical ocean. Results for five time windows from the middle Miocene to the late Pleistocene indicate pH-depth profiles similar to that of the modern ocean in this area, which suggests that this method may greatly aid in our understanding of the global carbon cycle.