Renal T-cell lymphoma with cerebral metastasis in a dog with chronic canine ehrlichiosis

A renal T-cell lymphoma with exclusive cerebral metastasis was diagnosed in a 5-year-old Staffordshire bull terrier bitch euthanased for aggression. This is the first recorded case of primary renal lymphoma in a dog. Immune suppression, due to chronic canine monocytic ehrlichiosis, may account for the unusual primary site and metastatic pattern of the tumour.     

Carbon kinetics of milk formation in Holstein cows in late lactation

Carbon transfer to milk in Holstein cows in late lactation was measured by introducing changes in the natural stable carbon isotope composition of the feed. Six Holstein cows in mid-lactation were placed on a diet naturally low in 13C (-25.0% vs Pee Dee belemnite [PDB] an international carbon isotope standard), based on alfalfa-barley, and six others were placed on a diet naturally enriched in 13C (-11.5% vs PDB), based on corn. After a 7-wk equilibration period on these diets, three cows were switched from alfalfa-barley to corn, and three were switched from corn to alfalfa-barley. The three other cows in each group served as controls. 13C/12C ratios were measured in daily morning milk samples during the week before and for 6 wk after the changes in diet. After the diets had been switched, milk isotope ratios rapidly approached the isotopic composition of the new diet, indicating rapid transfer of dietary carbon into milk. The data were consistent with a model whereby milk was synthesized from a single precursor pool that responded rapidly to dietary perturbation. The milk precursor pool had a half-life of approximately .9 d and had a mass of approximately 7 kg of carbon, which was renewed daily by the entry of 5 kg of digestible dietary carbon.     

A modified technique for flushing ova from the sheep uterus

Abstract

Extract

Sheep ova are normally obtained from the reproductive tract using the flushing techniques described by Hunter et al. (1955) Cumming, I. A. and McDonald, M. F. 1967. The production of ova by New Zealand Romney ewes following hormonal stimulation. N.Z. Jl agric. Res., 10: 226–236. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]. Oviduct flushes, in the writers' experience, give a higher recovery of ova than uterine flushes, but they result in more adhesions of the tract, which can cause infertility. Consequently, the development of satisfactory uterine flushing techniques appears necessary before ova can be recovered repeatedly from superior ewes. This paper describes such a technique.     

Mechanical injury and fungal infection induce acquired resistance in Norway spruce

Norway spruce trees (Picea abies (L.) Karst.) pretreated by wounding and fungal infection showed highly enhanced resistance to a subsequent challenge inoculation with the pathogenic bluestain fungus Ceratocystis polonica (Siem.) C. Moreau. This is the first time the effectiveness of the constitutive and inducible defenses has been shown to depend on prior wounding and infection in conifers, although such acquired resistance has previously been found in several angiosperms. Trees that were pretreated with a combination of 12 bark wounds (1.6 x 10 cm), four fungal inoculations and four sterile inoculations 1-15 days before mass inoculation with C. polonica at 400 inoculations per square meter over a 0.8 m stem section had significantly shorter necroses in the phloem, less bluestained sapwood, and less dead cambium than untreated control trees. Pretreatment with four fungal or sterile inoculations alone did not lead to enhanced resistance. Pretreatment by bark wounding alone seemed to provide an intermediate degree of resistance compared to bark wounding, fungal inoculations and sterile inoculations combined. All trees had a marked increase in the number of resin ducts in the year of inoculation compared with previous years, suggesting that formation of traumatic resin ducts play an important role in the development and maintainance of enhanced resistance.     

Effects of intravenous infusion of high levels of potassium and sodium on mineral metabolism in sheep

A metabolism trial was conducted with 18 crossbred (Finn x Dorset x Suffolk) wethers, fitted with indwelling jugular catheters and abomasal and ileal cannulas, to determine the effects of high levels of i.v.-infused K and Na on mineral metabolism. The wethers (40 kg) were fed 800 g daily of a 60% concentrate diet in two equal portions at 0800 and 1900. Six wethers were infused randomly with 19 g K+, six with 10.6 g Na+ (chloride salts) and the other six with physiological saline solution (1.2 g Na) per day. Potassium chloride or NaCl infusion had no effects on apparent absorption, retention, flow or partial absorption of Mg, Ca and P in the digestive tract compared with physiological saline infusion. With all treatments, Mg and Ca were absorbed proximal to the abomasal cannula. Magnesium was secreted into, whereas Ca and P were absorbed from, the small intestine. Phosphorus was secreted both in the stomach and large intestinal regions of the digestive tract. Major sites of K and Na absorption were the small and large intestines, respectively. Infusion of K increased (P less than .05) retention of K compared with Na infusion. Infusion of Na increased (P less than .05) excretion and retention of Na compared with K infusion. Serum minerals were not changed by K or Na infusion compared with saline. The results of this experiment indicate that the depressing effects of K on Mg absorption are not attributable to high levels of absorbed K, but rather to K present in the digestive tract prior to the small intestine.     

Transpiration increases during the dry season: patterns of tree water use in eucalypt open-forests of northern Australia

Australian savannas exhibit marked seasonality in precipitation, with more than 90% of the annual total falling between October and May. The dry season is characterized by declining soil water availability and high vapor pressure deficits (up to 2.5 kPa). We used heat pulse technology to measure whole-tree transpiration rates on a daily and seasonal basis for the two dominant eucalypts at a site near Darwin, Australia. Contrary to expectations, transpiration rates were higher during the dry season than during the wet season, largely because of increased evaporative demand and the exploitation of groundwater reserves by the trees. Transpiration rates exhibited a marked hysteresis in relation to vapor pressure deficit, which was more marked in the dry season than in the wet season. This result may be attributable to low soil hydraulic conductivity, or the use of stored stem water, or both. Tree water use was strongly correlated with leaf area and diameter at breast height and there were no differences in transpiration between the species studied. These results are discussed in relation to scaling tree water use to stand water use.