The relationship between certain blood cations in cows with milk fever and both the state of consciousness and the position of cows when attended

In one study, a comparison was made of the concentrations and ratios of certain blood cations in 2 groups of cows with milk fever, one showing normal consciousness (n = 8) and the other depressed consciousness (n = 24). There were no significant differences in the mean concentrations of serum total calcium, plasma inorganic phosphorus and potassium, erythrocyte sodium and potassium, the serum calcium/serum magnesium ratio or the plasma sodium/erythrocyte sodium ratio. There were significant differences (all P less than 0.05) in the mean (+/- SD) concentrations of serum magnesium and plasma sodium concentrations, and the plasma sodium/serum magnesium ratio of 0.8 +/- 0.28 vs 1.2 +/- 0.37 mmol/l, 155 +/- 3.0 vs 147 +/- 6.4 mmol/l and 180 +/- 40.1 vs 116 +/- 34.1 for normal vs depressed cows, respectively. In a second study, a comparison was made of the concentrations and ratios of the same blood cations in 3 groups of cows in different positions when attended for milk fever, namely standing (n = 6), sternal recumbency (n = 24) and lateral recumbency (n = 31). There were no significant differences between the mean concentrations or ratios of any of the cations.     

Black soil blindness: A new mycotoxicosis of cattle grazing Corallocytostroma-infected Mitchell grass (Astrebla spp)

A new, fatal mycotoxicosis of cattle has been recognised in north-western Australia. A feeding trial confirmed the toxicity of a previously unknown species of Corallocytostroma that grows on Mitchell grass (Astrebla spp). The disease has been colloquially named ‘black soil blindness’ because its most prominent features are its confinement to pastures on black soil, and blindness and death of affected animals. Over 500 cattle have died and considerable subclinical disease is present. Above average wet season rainfall and extended growing seasons may explain the emergence of the fungus. The disease is important because cattle production in large areas of Australia utilise Mitchell grass pastures.     

The effects of delays between restraint and sampling on some blood parameters in sheep

Twenty three non pregnant, non lactating aged Merino and Border Leicester ewes were subject to four jugular venipunctures one hour apart (times 0, 1, 2 and 3). Four different delay intervals of 12.5, 64.0, 128.0 and 252.9 seconds between catching and sampling (delays 1, 2, 3 and 4) were used on each sheep in a random manner. Estimates were made of packed cell volumes (PCVs), plasma and erythrocyte sodium and potassium concentrations. The mean PCV at time 0 of 35.4 per cent was significantly higher than the levels of 33.1, 31.8 and 32.2 per cent at times 1, 2 and 3 respectively. There was no significant difference between the means at times 1, 2 and 3. The mean plasma potassium concentrations at time 0 of 4.37 mmol/l was significantly higher than the levels of 4.16 and 4.14 mmol/l at times 1 and 3 respectively. Delays had no significant effects on the means of any of the parameters studied. The findings strongly suggest that sheep become excited by initial handling but not by subsequent venipunctures and that a delay between catching and sampling of between 12.5 and 252.9 second has no effect on the blood constituents studied.     

The isolation of Yersinia species from retailed sausages containing venison

Thirteen isolates of Yersinia spp., regarded as environmental strains, were recovered from 70 sausages containing venison which were presented for sale through retail outlets. It is not possible to incriminate venison as the source of these strains because the sausages contained other food ingredients. The pathogenic potential of such environmental strains remains unclear.     

Normal anatomical and histochemical characteristics of the lacrimal glands in the American bison and cattle

Dorsal lacrimal glands, superior glands of the third eyelid and Harderian glands (deep gland of the third eyelid) from 19 bison and 18 cattle free of apparent ocular disease were examined to compare the normal anatomical properties of these glands. All glands were characterized and measured (length and width). The gross anatomy of the dorsal lacrimal glands was similar, with the exception of a bipartite gland in cattle. The bison's superior gland of the third eyelid and Harderian gland was longer as compared with cattle. A subset of the bison and cattle samples (five bison and five cattle) was sectioned for histological and histochemical analysis. The histology of the dorsal lacrimal and superior gland of the third eyelid revealed tubuloalveolar cells with basophilic vacuolated cytoplasm in bison and eosinophilic granular cytoplasm in cattle. The Harderian glands consisted of a tubuloalveolar anterior part combined with large lumens acini lined with cuboidal epithelium in the posterior part; the posterior part of the bison Harderian gland was more predominant than in cattle samples. Mucosubstance histochemistry revealed acidic and neutral glycoproteins with similar staining patterns in all glands of both species.     

The tannin content of rapeseed meals

1. The presence of varying amounts of sinapine, a hydroxylated cinnamic acid derivative, in rapeseed meals has been shown to interfere with the usual methods of tannin estimation.

2. When correction was made for such sinapine contribution the corrected tannin levels were from 18 to 45% lower than those previously reported.     

Blood pathophysiological changes in sheep following a prolonged (18-hour) period of hypocalcaemia induced by Na2EDTA solution.

Six aged Merino ewes were used in an experiment in which five were infused with 4.7% Na2EDTA solution intravenously for 18 h at a rate designed to produce hypocalcaemia and maintain recumbency, and five with 0.9% sodium chloride solution at the same rate for the same period (four were infused at different times with both solutions). Blood samples were collected every 3 h and determinations made of plasma Ca, Na, K, Mg, and inorganic P (PiP), erythrocyte Na, K and Mg, and PCV. Three of the hypocalcaemic sheep took 36-64 h to regain their feet. Plasma Ca and K, and erythrocyte Na showed significant (all P less than 0.01) decreases in the group infused with Na2EDTA compared with the group infused with saline while PCVs were significantly (P less than 0.01) greater in the former group. The sheep model used could be suitable for the study of the effects of prolonged hypocalcaemia and recumbency in cows.     

Enhancement of cation diffusion rates across the 410-kilometer discontinuity in Earth's mantle

Rates of cation diffusion (magnesium, iron, and nickel) have been determined in olivine and its high-pressure polymorph, wadsleyite, at 9 to 15 gigapascals and 1100 degrees to 1400 degreesC for compositions that are relevant to Earth's mantle. Diffusion in olivine becomes strongly dependent on composition at high pressure. In wadsleyite, diffusion is one to two orders of magnitude faster than in olivine, depending on temperature. Homogenization of mantle heterogeneities (chemical mixing) and mineral transformations involving a magnesium-iron exchange will therefore occur considerably faster in the transition zone than at depths of less than 410 kilometers.