Systemic and pulmonary antibody responses of calves to Pasteurella haemolytica after intrapulmonary inoculation.

Systemic and pulmonary antibody responses of calves to Pasteurella haemolytica were evaluated by measuring immunoglobulin production in blood for 9 days and in pulmonary lavage fluid for 7 days after intrapulmonary inoculation. Clinical signs, pulmonary lesions, pulmonary and systemic inflammatory response, and amount of antigen in lavage fluid were used to evaluate the response of calves to challenge with P haemolytica. The pulmonary response consisted of production of IgG, IgE, and IgM antibodies to P haemolytica antigens and a 17- to 68-fold increase of cells in lavage fluid 8 hours after inoculation, with a gradual decrease toward normal. Antibodies of the IgM isotype to P haemolytica were demonstrated as early as 8 hours through 7 days after inoculation in 3 of 3 calves. Of the anti-P haemolytica isotypes, IgM was found in the highest concentration. In all of the inoculated calves, IgE was found 1 to 2 days after inoculation, and IgG was found in 2 of 3 inoculated calves from day 1 through 7 after inoculation. Detection of IgG correlated with smaller pulmonary lesions. Immunoglobulin A was not detected in lavage fluid. Serum was evaluated for IgG and IgM antibody response to P haemolytica. Specific IgM was detectable 5 days after inoculation, and IgG was detectable 7 days after inoculation. Pasteurella haemolytica antigens were not detected in serum or plasma. A transient increase in neutrophil count was found 8 hours after inoculation, with return to baseline values by 24 hours after inoculation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Estimation of density—Moisture—Stress functions from uniaxial compression of unsaturated, structured soils

A quasi-theoretical soil compaction model is presented which gives good estimates (r²=0.980−0.995, P<0.001) of the complete density-stress compression line for soils of variable initial moisture content under static loads from 0 to 1.0 MPa. The 3 unknown parameter coefficients of the generalized model equation are shown to be highly correlated to several soil properties such as moisture content, pre-compression (initial) void ratio, texture, organic matter content ans the Atterberg consistenct limits. A 3-tier classification for partition consisteny limits. A-tier claasificaton for pationing soils into groupings of response to compressive stress is proposed for soil compaction modeling. This categorization is based on soil plasticity and the existence of a “compaction threshold“ sensitivity threshold” in most soils.     

Rapeseed meals in broiler diets: Effect on performance and sensory evaluation of carcasses

1. The effect of including rapeseed meal (RSM) in lieu of soyabean meal in broiler diets was determined.

2. Live‐weight gains, from 8 to 63 d, were depressed when the diet contained 150 g RSM/kg and there was a highly significant negative correlation between weight gain and inclusion rate of RSM over this period.

3. The efficiency of food utilisation was worse when the diet included 150 g solvent RSM/kg than when it contained no RSM: food efficiency was consistently poorer whenever RSM was included in the diet but the difference was significant only when the diet contained 10 g tallow/kg.

4. Carcasses from birds fed on diets containing 10 g tallow/kg had a better appearance than those from birds on diets containing 30 g tallow/kg, while the flavour of meat from birds fed on a diet containing 150 g solvent RSM/kg treatment was adversely affected. However, up to 100 g solvent RSM/kg may be included in broiler diets without affecting appearance, taste, texture or acceptability of the meat.

5. Inclusion of 50 g or more, solvent RSM/kg reduced growth rate and worsened food efficiency.     

Plasma lipopolysaccharide elevations in cattle associated with early-stage infection by Fasciola hepatica

Fasciolosis is an endemic zoonotic parasitic disease with significant impacts on human health and both animal health and production. Early post-infection impacts on the host remain unclear. The objective of this study was to determine the changes, if any, to levels of endotoxin in cattle plasma in response to early-stage infection with Fasciola hepatica. Thirty-six (36) commercial bred cattle were experimentally infected with approximately 400 viable metacercariae. Plasma lipopolysaccharide (endotoxin) levels were examined on 24 occasions from 0 h before infection to 336 h after infection using the Limulus Amoebocyte Lysate chromogenic end point assay and compared with that of six (6) uninfected control animals. Peak lipopolysaccharide levels in infected animals were reached at 52 h after infection and returned to pre-infection levels at time 144 h after infection. Infected animals had significantly elevated lipopolysaccharide levels between 24 and 120 h after infection when compared to uninfected animals. The mean change in endotoxin units (EU)/mL over time after infection was statistically significant in infected animals. Elevations of lipopolysaccharide occurred in all infected animals suggesting a possible repeatable and titratable endotoxemia conducive to therapeutic agent model development.     

Growth and metabolism in somatotropin-treated steers: III. Protein synthesis and tissue energy expenditures

Rates of in vivo protein synthesis in intercostal, sartorius and semitendinosus muscle and in the heart, liver, kidneys, rumen and jejunum were determined in 20 growing Hereford steers treated for 112 d with daily subcutaneous injections of either saline (S) or recombinantly derived bovine somatotropin (rBST; 20.6 mg/d). In vitro rates of protein synthesis and energy expenditures associated with Na+, K+ transport also were determined in external intercostal muscle, liver, kidneys and jejunum. Neither in vivo nor in vitro tissue protein fractional synthetic rates (mg/[g protein.d]), using either the plasma (P) or intracellular fluid (ICF) phenylalanine specific radioactivity for the precursor pool, were affected by rBST treatments. Energy expended on Na+, K+ transport was greater (P less than .1) in the livers of rBST-treated steers, which would increase the maintenance energy expenditures of these steers. Protein accretion rates in the liver, kidneys, stomach, hide, and head, feet and tail of rBST-treated steers were greater (P less than .05) than in S steers. Tissue amino acid profiles were not affected by rBST treatments except in the rumen, where profiles suggested that less collagen was present in rumen wall tissue protein of rBST steers. Plasma phenylalanine entry rates also were not affected by rBST treatment; muscle protein synthesis accounted for a minimum of 20% of this entry rate.     

Segmental axonopathy of Merino sheep in New Zealand

AIM: To investigate an axonopathy of Merino sheep that caused progressive hindlimb ataxia and slight to moderate paresis, with the purpose of understanding its pathogenesis.

METHODS: Tissues were fixed in buffered paraformaldehyde or paraformaldehyde and glutaraldehyde, processed into wax and epoxy resin, respectively, and examined by light and electron microscopy. Fresh frozen spinal cord and trigeminal nerve roots were subjected to homogenisation, centrifugation and two-dimensional electrophoresis. Selected protein spots were identified using matrix-assisted laser desorption ionisation (MALDI) mass spectrometry.

RESULTS. By light microscopy, there were large pale foamy spheroidal axonal swellings affecting peripheral as well as central axons. By electron microscopy, these were shown to contain many membrane-bound vesicles. The main abnormalities in expressed proteins involved cytoskeletal elements and myosin heavy chain, the latter interpreted as associated with the molecular motor myosin Va.

CONCLUSIONS: The disorder is the same as that described in Merinos in Australia as segmental axonopathy, and believed to have an inherited aetiology. The lesions and protein changes indicate abnormalities of the cytoskeleton, its relationship with the myelin sheath, and myosin Va molecular motor. The consequence appears to be abnormal axonal transport and inability to maintain the integrity of axons and their myelin sheaths.     

Sexing chick embryos: a rapid and simple protocol

1. Analysis of gene expression in the developing chick gonads requires the collection of male and female tissues from embryos between 3.5 d and 8.5 d of development. However, male and female chick embryos are indistinguishable by morphological examination before d 7.5 of development. 2. Sex identification of earlier embryos is only possible by molecular methods, which at present are laborious and time consuming. 3. We have devised a PCR-based sexing protocol which combines both sex specific and control reactions in a single tube assay. The assay is rapid and effective over a wide range of DNA concentrations and is tolerant of poor quality DNA. 4. Procedures are described for identifying the sex of individual embryos using either tissue samples or a small number of cells recovered from amniotic fluid.     

Immune response of chickens inoculated with a recombinant avian leukosis virus

Specific-pathogen-free embryos (18-day incubation) and hatched chicks were inoculated with a recombinant avian leukosis virus (ALV) produced by recombinant DNA techniques. Enzyme-linked immunosorbent assays were used to measure the production of viral-protein-specific antibody and the viral protein, p27, in the serum at 2, 5, 8, 14, and 20 weeks of age. Of the inoculated chickens surviving to 20 weeks, 64% produced viral-protein-specific antibodies and 42% transiently produced the viral protein, p27. Chickens inoculated as embryos did not differ significantly from those inoculated at hatch with respect to antibody and viral protein production. Antibody production peaked at 5 weeks postinoculation and declined over the remaining 15 weeks of the study. No evidence of chronic tolerant infection or mortality due to neoplastic disease was found.     

The Effects of Replacing Dicalcium Phosphate with Busumbu Rock Phosphate on Performance and the Mechanical Properties of Bone in Growing Chicks

Three hundred, day-old broiler chicks, with an average initial weight of 41.8±1.79 g, were used in a 15-day study (10 birds per battery cage) to characterize their performance and fluorine status when dicalcium phosphate (DCP) was replaced by Busumbu rock phosphate (BRP) as the source of phosphorus in the chicks' ration. The treatments comprised a standard ration with BRP replacing 0, 25%, 50%, 75% or 100% of DCP. Replacing DCP with BRP significantly reduced the final weight of the chicks (p<0.01), feed intake (p<0.01), weight gains (p<0.01) and dry matter digestibility (p<0.05) but increased (p<0.05) the feed-to-gain ratio. True phosphorus absorption and the percentage of phosphorus in the tibia were not affected by increasing amounts of BRP in the diet. Increasing levels of BRP in the diet linearly reduced (p<0.01) the percentage bone ash, calcium, Ca:P ratio, ultimate breaking force, bending moment, stress, and modulus of elasticity. Leg stiffness, lameness, reduced feed intake, and a decline in general health were recorded in 10–40% of the chicks on 75% and 100% BRP, respectively. These results suggest that excessive ingestion of fluorine from the BRP caused the reduction in the chicks' performance.