Enzymes of glucose and fatty acid metabolism of liver, kidney, skeletal muscle, adipose tissue and mammary gland of lactating and non-lactating sheep

The effect of peak lactation on the activities of a number of enzymes of glucose and lipid metabolism of perirenal and subcutaneous adipose tissue, skeletal muscle, liver, kidney cortex and mammary parenchyma of sheep are described. Enzymes studied included hexokinase (glucose utilization), pyruvate carboxylase (gluconeogenesis), pyruvate dehydrogenase (glucose oxidation and production of acetyl CoA for fatty acid synthesis), acetyl CoA carboxylase (fatty acid synthesis) and glycerol-3-phosphate acyltransferase (fatty acid esterification). Major changes that were found include a decrease in activities of enzymes of fatty acid synthesis and esterification in adipose tissues, decreased activity of pyruvate dehydrogenase in muscle and adipose tissues and increased pyruvate carboxylase; there was no change in activities of enzyme of fatty acid esterification in liver. Activities of hexokinase, acetyl CoA carboxylase and glycerol-3-phosphate acyltransferase have been estimated per tissue; this shows the quantitative importance of limiting glucose utilization by muscle and of suppression of fatty acid synthesis in adipose tissue for efficient partitioning of nutrients for milk production.     

Dog response to inactivated canine parvovirus and feline panleukopenia virus vaccines

Inactivated canine parvovirus (CPV) and inactivated feline panleukopenia virus (FPV) vaccines were evaluated in dogs. Maximal serologic response occurred within 1-2 weeks after vaccination. Antibody titers then declined rapidly to low levels that persisted at least 20 weeks. Immunity to CPV, defined as complete resistance to infection, was correlated with serum antibody titer and did not persist longer than 6 weeks after vaccination with inactivated virus. However, protection against generalized infection was demonstrated 20 weeks after vaccination. In unvaccinated dogs, viremia and generalized infection occurred after oronasal challenge with virulent CPV. In contrast, viral replication was restricted to the intestinal tract and gut-associated lymphoid tissue of vaccinated dogs. Canine parvovirus was inactivated by formalin, beta-propiolactone (BPL), and binary ethylenimine (BEI) in serum-free media; inactivation kinetics were determined. Formalin resulted in a greater loss of viral HA than either BEI of BPL, and antigenicity was correspondingly reduced.     

Yersinia enterocolitica infection in breeding colonies of ruffed lemurs

Two outbreaks of yersiniosis caused by Yersinia enterocolitica occurred in breeding colonies of red ruffed lemurs (Varecia variegata rubra) and black and white ruffed lemurs (Varecia variegata variegata) housed in outdoor enclosures during the winter breeding season and spring birth season, respectively. Seven of 11 animals at risk in the combined outbreaks became ill, and 3 died of acute to chronic infection. Clinical signs included anorexia, lethargy, diarrhea, abdominal pain, and hyperpyrexia. Necropsy findings included ulcerative enterocolitis and multifocal necrosis and abscess formation in mesenteric lymph nodes, liver, spleen, kidneys, and lungs. Histologically, lesions were characterized by necrotizing inflammation containing masses of basophilic bacteria. Yersinia enterocolitica serotype 0:2 was isolated from lesions. Neomycin sulfate given orally and chloramphenicol given intramuscularly were effective in treatment early in the course of the disease or in mild cases. In severe cases, lemurs did not respond to antibiotic and fluid therapy. Exposure to soil contaminated with infected rodent feces, stress, and behavioral factors in the ruffed lemur species are believed to have precipitated the infection.     

A modified live canine parvovirus vaccine. II. Immune response

The safety and efficacy of an attenuated canine parvovirus (A-CPV) vaccine was evaluated in both experimental and in field dogs. After parenteral vaccination, seronegative dogs developed hemagglutination-inhibition (HI) antibody titers as early as postvaccination (PV) day 2. Maximal titers occurred within 1 week. Immunity was associated with the persistence of HI antibody titers (titers greater than 80) that endured at least 2 years. Immune dogs challenged with virulent CPV did not shed virus in their feces. The A-CPV vaccine did not cause illness alone or in combination with living canine distemper (CD) and canine adenovirus type-2 (CAV-2) vaccines, nor did it interfere with the immune response to the other viruses. A high rate (greater than 98%) of immunity was engendered in seronegative pups. In contrast, maternal antibody interfered with the active immune response to the A-CPV. More than 95% of the dogs with HI titers less than 10 responded to the vaccine, but only 50% responded when titers were approximately 20. No animal with a titer greater than 80 at the time of vaccination became actively immunized. Susceptibility to virulent CPV during that period when maternal antibody no longer protects against infection, but still prevents active immunization, is the principal cause of vaccinal failure in breeding kennels where CPV is present. Reduction, but not complete elimination, of CPV disease in large breeding kennels occurred within 1-2 months of instituting an A-CPV vaccination program.     

The use of lung biopsy to determine early lung pathology and its association with health and production outcomes in feedlot steers

The objectives of this study were to determine if percutaneous lung biopsy can be used to characterize early pathologic changes in bovine lung associated with bovine respiratory disease (BRD), to determine if specific infectious respiratory pathogens can be identified in association with these changes, and to determine whether pulmonary pathology at arrival and at the time of initial diagnosis are associated with health and production outcomes. One hundred auction-market derived crossbred steer calves from a commercial feedlot in southern Alberta were included in this study. A percutaneous lung biopsy technique was used to obtain lung samples from the right middle lung. Steers were sampled 295 times yielding 283 samples with 210 (74%) containing lung tissue. Overall, histopathological changes were observed in 20 (9.5%) of lung biopsy samples. There were too few samples with pathology to reveal an association between lung pathology and subsequent health events. In general, percutaneous lung biopsy can be done safely on feedlot steers in a commercial feedlot setting with few clinical side effects. This technique did not prove useful as a diagnostic tool or prognostic indicator for early BRD. However, it may be useful for the diagnosis of BRD in targeted populations of commercial feedlot steers.     

Progress in the development of vaccines and diagnostic reagents to control tuberculosis in cattle

The sharp rise of bovine tuberculosis (TB) in Great Britain and the continuing problem of wild life reservoirs in countries such as New Zealand and Great Britain have resulted in increased research efforts into the disease. Two of the goals of this research are to develop (1) cattle vaccines against TB and (2) associated diagnostic reagents that can differentiate between vaccinated and infected animals (differential diagnosis). This review summarises recent progress and describes efforts to increase the protective efficacy of the only potential TB vaccine currently available, Mycobacterium bovis BCG, and to develop specific reagents for differential diagnosis. Vaccination strategies based on DNA or protein subunit vaccination, vaccination with live viral vectors as well as heterologous prime-boost scenarios are discussed. In addition, we outline results from studies aimed at developing diagnostic reagents to allow the distinction of vaccinated from infected animals, for example antigens that are not expressed by vaccines like Mycobacterium bovis Bacille-Calmette-Guérin, but recognised strongly in Mycobacterium bovis infected cattle.     

The use of MPB70 and MPB83 to distinguish between bovine tuberculosis and paratuberculosis

In order to demonstrate the potential to distinguish paratuberculosis (PTB) from bovine tuberculosis infection (TB), ELISAs with M. bovis-specific MPB70 or MPB83 as capture antigens were developed and tested on two groups of cattle: Group A comprised 23 animals positive for Mycobacterium avium paratuberculosis (Map) and TB free. Group B comprised 48 animals from a Map free herd during the previous 5 years, but confirmed as tuberculous by positive results on PPD testing and M. bovis culture. Results demonstrated a significant difference (p < 0.01) between reactivity of sera from these groups, encouraging the study of purified proteins to differentiate between both diseases.     

The impact of conservation on the status of the world's vertebrates

Using data for 25,780 species categorized on the International Union for Conservation of Nature Red List, we present an assessment of the status of the world's vertebrates. One-fifth of species are classified as Threatened, and we show that this figure is increasing: On average, 52 species of mammals, birds, and amphibians move one category closer to extinction each year. However, this overall pattern conceals the impact of conservation successes, and we show that the rate of deterioration would have been at least one-fifth again as much in the absence of these. Nonetheless, current conservation efforts remain insufficient to offset the main drivers of biodiversity loss in these groups: agricultural expansion, logging, overexploitation, and invasive alien species.     

Effect of different grazing management systems on the herbage mass and pasture height of a Nardus stricta grassland in western Scotland, United Kingdom

The aims of this study were to examine the effect of three grazing treatments (year‐round stocking rates of 0·8 ewes ha^?1, 0·5 ewes ha^?1 and 0·5 ewes ha^?1 plus grazing cattle in summer), imposed for 4 years, on the herbage mass and surface height of a Nardus stricta‐dominated grassland in western Scotland and to obtain estimates of annual productivity of this grassland. Nardus stricta‐dominated grassland comprised proportionately 0·20 of the grazing area. Stocking rate of sheep had no significant effect on the herbage mass of the grassland in the first 2 years of the experiment, although mean summer pasture heights were significantly higher under the lower stocking rate of sheep. The pasture on the treatment with cattle grazing in summer had a significantly lower herbage mass and lower surface height than the two sheep‐only grazing treatments. Year‐to‐year variation in the herbage mass and surface height of herbage in summer was greater than the effect of treatments. Despite changes in surface height, the structural diversity of the grasslands was not increased by the treatments. The annual production of vascular plant material ranged from 417 g DM m^?2 in 1994 to 628 g DM m^?2 in 1996.