Nursing sickness in lactating mink (Mustela vison). II. Pathophysiology and changes in body fluid composition.

An investigation of the pathophysiological characteristics of nursing sickness in mink was carried out as a follow-up study of a previous epidemiological survey at a Danish fur research farm during the 1989 breeding season. In a total of 48 nursing females of the Standard Black and Pastel type, concentrations of several pertinent biochemical constituents of whole blood, plasma, urine and skeletal muscle were determined in order to identify nutritional and metabolic factors involved in the origin and development of the disease. Compared to the reference data obtained in 17 apparently normal lactating dams the findings in 31 females suffering from nursing sickness presented varying clinical and biochemical signs of progressive dehydration and emaciation: aldosteronism, hypovolemia, hyponatremia, hyperkalemia (in the face of muscle potassium depletion), hyperglycemia and azotemic acidemia. Neither ketosis nor severe lactacidemia was observed. The urine was almost devoid of sodium and chloride, and urinary potassium concentration diminished by approximately 50%. The concentrating ability of the kidneys was reduced to less than one third of the maximum value. The results were consistent with severe dehydration and emaciation due to heavy losses of energy, water and body mass along with increasing milk production. The progressive nature of the disease supported the hypothesis that nursing sickness is due to the combined effects of heavy milk production and excessive tissue catabolism along with reduced or ceased dietary intake, and maybe increasing environmental stress. In the advanced stage of the disease coma and death appear to be the inevitable outcome of the metabolic strains for continuing milk production.     

Nitrogen cycling in organic farming systems with rotational grass–clover and arable crops

Organic farming is considered an effective means of reducing nitrogen losses compared with more intensive conventional farming systems. However, under certain conditions, organic farming may also be susceptible to large nitrogen (N) losses. This is especially the case for organic dairy farms on sandy soils that use grazed grass–clover in rotation with cereals. A study was conducted on two commercial organic farms on sand and loamy sand soils in Denmark. On each farm, a 3‐year‐old grass–clover field was selected. Half of the field was ploughed the first year and the other half was ploughed the following year. Spring barley (Hordeum vulgare L.) was sown after ploughing in spring. Measurements showed moderate N leaching during the pasture period (9–64 kg N ha^?1 year^?1) but large amounts of leaching in the first (63–216 kg N ha^?1) and second (61–235 kg N ha^?1) year after ploughing. There was a small yield response to manure application on the sandy soil in both the first and second year after ploughing. To investigate the underlying processes affecting the residual effects of pasture and N leaching, the dynamic whole farm model farm assessment tool (FASSET) was used to simulate the treatments on both farms. The simulations agreed with the observed barley N‐uptake. However, for the sandy soil, the simulation of nitrate leaching and mineral nitrogen in the soil deviated considerably from the measurements. Three scenarios with changes in model parameters were constructed to investigate this discrepancy. These scenarios suggested that the organic matter turnover model should include an intermediate pool with a half‐life of about 2–3 years. There might also be a need to include effects of soil disturbance (tillage) on the soil organic matter turnover.     

Distribution of Feline Blood Types Detected in the Copenhagen Area of Denmark

Jensen, A. L., A. B. Olesen and J. Arnbjerg: Distribution of feline blood types detected in the Copenhagen area of Denmark. Acta vet. scand., 1994, 35, 121-124.–The purpose of the present study was to make the first survey of the distribution of feline AB blood types in the Copenhagen area of Denmark. A total of 244 cats (139 purebred cats and 105 Domestic Shorthair cats) were tested. 93% of all tested cats had blood type A. Neither an AB nor an O type cat was detected and thus, the frequency of blood type B among all tested cats was 7%. Most type B cats were purebred cats (Birman, British Shorthair and Persian cats). No association between sex and blood type could be demonstrated among British Shorthair and Persian cats. Thus, the present study indicates that cats in Denmark predominantly have blood type A, and that blood type B cats are rare, except for certain breeds such as Birman and British Shorthair cats.     

Systemic antibacterial drug use in dogs in Australia

A survey of veterinarians' use of antibacterial drugs was conducted by distributing a questionnaire to Australian practitioners. Respondents were asked to indicate their general patterns of use of various systemic antibacterial drugs and drug combinations in dogs and their approach to certain specified clinical disorders. Overall, antibacterials of the p-lactam type (penicillins and cephalosporins) were most commonly used. Other antibacterials with substantial use were doxycycline, sulphonamide-trimethoprim, metronidazole, fluoroquinolones and clindamycin. Drug selection for different disorders was generally appropriate when compared with recommendations in recent texts, although inappropriate use was evident in some circumstances.     

Fungicide treatments affect yield and moisture content of grain and straw in winter wheat

Straw and grain yield and water content in both grain and straw were measured during 3 years in 17 varieties of winter wheat following treatments with different fungicides. The water content of the straw varied significantly dependent on year, variety and fungicide treatment. In 1998, the water content in straw was significantly higher after the use of strobilurins compared with untreated and EBI fungicides (ergosterol biosyntesis inhibitors). On average water content in 10 varieties increased from 15% in untreated to 31% after applying two full dosages of azoxystrobin. In 1999 and 2000, lower dosages of azoxystrobin were used and water content increased only by 2–4 percentage units. The results indicate that in some years and with high doses precaution has to be taken following the use of strobilurins regarding handling and removing of the straw, which likely will include postponement of baling. Water content in grain was also increased significantly from fungicide treatments, but the increase was minor and at the maximum increase found to be 1.1% percentage unit. The effect of fungicide input on water content in grain was reduced much faster during the ripening period than for water content in straw. Fungicide treatments and varieties significantly influenced straw yields. The yield increases in straw varied between 0 and 1.0 tonnes/ha depending on year and variety, and was on average 0.42 tonnes/ha for two fungicide treatments. Two fungicide applications carried out at GS 31 and 45–55 gave only slightly higher increases compared with one application around ear emergence. Varieties showed variable increases following the use of fungicides. The variation was not influenced by the straw length (crop height). The increases in straw yield from fungicide treatments were relatively low compared to the increases in grain yield and no clear correlation was found between grain yield increases and straw yield increases.     

Sensitivity of crop yield and N losses in winter wheat to changes in mean and variability of temperature and precipitation in Denmark using the FASSET model

Abstract

Sensitivity of wheat yield and soil nitrogen (N) losses to stepwise changes in means and variances of climatic variables were determined using the FASSET model. The LARS-WG was used to generate climate scenarios using observed climate data (1961–90) from two sites in Denmark, which differed in climate and soil conditions. Scenarios involved changes to (i) mean temperature alone, (ii) mean and variability of temperature, (iii) winter and summer precipitation amounts and (iv) duration of dry and wet series.

The model predicted lower grain yield and N uptake in response to increases in mean temperatures, caused by early maturity, with little change in variability. This, however, increased soil mineral N causing increased N losses. On sandy loam, larger temperature variability lowered grain yields and increased N losses coupled with higher variability at all the mean temperature ranges. On coarse sand, grain yields either remained unaltered or were slightly reduced when larger temperature variability was introduced to increase in mean temperatures of up to +2°C above baseline. However, introducing variability to further increase in mean temperatures lowered yields without any change in variability. Larger temperature variability did not affect soil mineral N and N₂O emissions, but increased N leaching on coarse sand.

Large response in grain yield, N uptake and soil N cycling, and in their variability was predicted when summer precipitation was varied, whereas only N leaching responded to changes in winter precipitation. Doubling the duration of dry series lowered grain yield and N removed by grain, but increased N leaching, whereas doubling the duration of wet series showed opposite effect. Predicted responses to changes in precipitation patterns were larger on coarse sand than on sandy loam. This study illustrates the importance of considering effects of changes to mean climatic factors, climatic variability and soil types on both crop yield and soil N losses.     

Effect of Dietary Fibre on Digestibility and Energy Metabolism in Pregnant Sows

This study was undertaken to provide information on the effect of two levels of dietary fibre (DF) [184 vs. 407 g DF kg^-1 dry matter (DM)] on the digestibility of nutrients and energy metabolism in pregnant sows during different stages of pregnancy. The amount of DF in the high-fibre diet was supplied by dried sugar beet pulp (20%) and oats, wheat bran and grass pellets. The intake of metabolizable energy (ME) was similar for both the low-fibre and the highfibre diet, with an average daily intake of 30.74 MJ. Digestibility of DM, organic matter, protein, fat and energy was significantly decreased by a high DF level, but no effect of the diets was observed on the stage of pregnancy. A high fibre level significantly increased the digestibility of DF, indicating that fibre from sugar beet pulp is more fermentable than fibre from cereals. Protein utilization increased during the pregnancy, but at a very low level, indicating that the protein level in diets for pregnant sows could be lower. Inclusion of extra DF in the diet significantly increased the amount of energy excreted as CH₄. Heat production was affected by diet, although not significantly (28.77 vs. 29.72 MJ day^-1 in the low-fibre and highfibre diets, respectively). The utilization of ME for energy retention was lower for the high-fibre diet as a result of increased hind-gut fermentation. There was similar relation between the net energy of the standard and the high-fibre diet either calculated using the official Danish feed evaluation (0.77) or experimental estimated value (0.81).