Boron nutrition of Pinus radiata in relation to soil development and management

Nutritional surveys in New South Wales Pinus radiata plantations have shown differences in both foliage and soil boron status, particularly as a result of variations in soil parent materials. Plantations on acid igneous parent materials are particularly susceptible to the development of B deficiency, which appears to be further exacerbated bu soil/landscape relationships, water stress and certain management practices.

Boron deficiency in P. radiata on acid igneous soils at Sunny Corner State Forest, N.S.W., was particularly noticeable on lower slopes which usually have relatively high available moisture. These lower-slope soils had severely leached surface horizons, less extractable B, and fewer B-sorption characteristics than the upper sections of the soil catena. These soil properties also adversely affect the capacity of these soils to retain either Na-borate or Ca-borate fertilizers (borax and colemanite, respectively). For equal amounts of B, up to 95% of the borax applied to in-situ soil columns rapidly moved beyond the top 0.3 m of the soil profiles within 21 months, while less than 16% of the colemanite had moved beyond the columns. Leached surface soils of the lower-slope site retained lesser amounts of either B-fertilizer.

Colemanite offers the most cost-effective means of maintaining adequate levels of soil-B in these soil types due to its lower solubility. Management of B deficiency in P. radiata involves appropriate site selection, forest management practices and fertilizers usage.     

Site variation in Pinus radiata plantations and implications for site specific management

685,000 ha of Pinus radiata(D. Don) plantations in Australia werecategorized using a matrix of mean annualrainfall, rainfall regime and Parent Rock Codefrom a Technical Soil Classification. Datawere obtained from a number of differentorganizations which in total managed nearly allthe Australian P. radiata plantations. The selected characteristics were those whichcould be obtained at an acceptable level ofconfidence from all sources. Such acharacterization of plantation sites provided asystem for utilization of technical informationand extrapolation of research results and alsoa basis for the development of Site SpecificManagement systems. Analysis of theinformation indicated the high degree ofvariability of environments in whichplantations have been established withinAustralia and also the distinctive nature ofindividual regions. Such differences betweenareas make extension of silvicultural andrelated information difficult from one area toanother without appropriate validation. Abroad comparison with 1.26 million hectares ofP. radiata plantations in New Zealandindicated only a small overlap of areas of sitetypes between Australia and New Zealand. Assumptions derived in one location on thesites, characteristics, models and/or genotypeswould require significant testing beforeconfident application could be undertaken toanother area. The value of a Site SpecificManagement system for research planning andapplication of research and operational resultswas demonstrated from analysis of a series ofexperimental trials assessing application offertilizer after thinning and from evaluationof soil carbon in P. radiataplantations.     

Comparison of four diagnostic tests for the identification of serum antibodies in small ruminants infected with Mycoplasma agalactiae

AIM: To determine the diagnostic capability of a newly developed Western blot (WB) assay for the detection of serum antibodies against Mycoplasma agalactiae compared with conventional serological tests, and to identify the best test for routine diagnostic use. METHODS: The serological test methods used were: two commercial indirect enzyme-linked immunosorbent assays (ELISA), viz ELISA-1, using a bacterial antigen preparation, and ELISA-2, using a recombinant protein (lipoprotein p48) antigen; the complement fixation test (CFT); and a newly developed WB assay, the latter both using a bacterial antigen preparation. Thirty sera from goats infected with M. agalactiae and 97 sera from non-infected sheep were tested using all four methods. RESULTS: Staining patterns in the WB were quite variable. An immuno-dominant band of 41 kDa was detected in 63% of sera from infected animals. The same band also appeared, although mostly very weakly, in 10% of sera from non-infected animals. When suspicious or very weak reactors were omitted, the diagnostic sensitivity (DSE) and diagnostic specificity (DSP), respectively, for the four assays were: WB=56.7%, 97.9%; ELISA-1=76.7%, 99.0%; ELISA-2=56.7%, 100%; and CFT=40.0%, 94.8%. CONCLUSIONS: ELISA-1 performed best in this comparison. While the WB can be used, it did not have a technical advantage over the ELISA. The CFT should be discouraged as the primary screening method for contagious agalactia and should be replaced by ELISA-1. Results from this study confirm that serological test methods for contagious agalactia are useful for the detection of infected flocks but will not detect every individual infected animal.     

The use of tramadol in a Labrador retriever presenting with self-mutilation of the tail

A 30-month-old Labrador retriever bitch with a history of atopy was presented for acute-onset tail biting that was leading to self-mutilation. The problem began 8 months before consultation and was resolved after 2 months, but it recurred 3 months later and continued for 3 months until the time of consultation. The current episode was difficult to interrupt and was being controlled through the use of an Elizabethan collar. There had been no history of injury to the tail. On examination of the tail, an irregularity was palpated approximately midway on the dorsal surface. Radiographs of the tail showed soft-tissue swelling cranially and presence of an ossicle between the mid-caudal vertebrae. Mutilation stopped with administration of tramadol and paracetamol and started again when the medication was discontinued. No behavior modification was implemented. Although there is a possibility that the tramadol was treating a psychogenically driven self-mutilation behavior, it is more likely that pain was the initiating cause for the behavior. This case report highlights the importance of careful medical evaluation of suspected behavioral problems and discusses the possible use of tramadol in self-mutilation.     

Supplemental betaine and peroxide-treated feather meal for finishing cattle

These studies evaluated the effects of betaine, provided either as feed-grade betaine or as concentrated separator by-product (CSB; desugared beet molasses), on performance and carcass characteristics of finishing cattle. In Exp. 1, 175 steers (410 kg initial BW) were fed a finishing diet based on steam-flaked and dry-rolled corn, and treatments included 10.5 and 21 g/d feed-grade betaine and 250 and 500 g/d CSB (supplying 15.5 and 31 g/d of betaine, respectively). Steers fed feed-grade betaine had greater (linear and quadratic effects, P < 0.1) DMI than control steers, but ADG and gain efficiencies were not affected by treatment. Dressing percent and backfat thickness was greater (P < 0.1) for steers that received feed-grade betaine than for controls. Longissimus muscle area was lower (P < 0.1) for steers supplemented with either feed-grade betaine or CSB than for control steers. Yield grades were higher for cattle receiving feed-grade betaine (quadratic effect, P < 0.1) than for control steers. Marbling scores were not affected by supplemental betaine, but the percentage of carcasses grading USDA Select was lower (linear and quadratic effects, P < 0.1) for steers fed feed-grade betaine than for control steers, predominantly due to a greater percentage grading USDA Choice. In Exp. 2, 312 heifers (343 kg initial BW) were used in a finishing study to evaluate the effects of graded levels of feed-grade betaine and peroxide-treated feather meal on performance and carcass characteristics. Treatments included two finishing diets (containing peroxide-treated or untreated feather meal) and four levels (0, 4, 8, and 12 g/d) of feed-grade betaine arranged in a 2 x 4 factorial. No significant interactions occurred between treatment of feather meal and betaine. Treatment of feather meal with hydrogen peroxide (5% wt/wt) increased in situ protein degradability but did not alter DMI, ADG, gain efficiencies, or carcass characteristics of heifers when it replaced untreated feather meal in the diet. Top-dressing feed-grade betaine to the diets had no effect on DMI, ADG, and gain efficiencies. Marbling scores were greater (cubic effect, P < 0.05) for heifers fed diets top-dressed with 4 and 12 g/d of feed-grade betaine, but other carcass characteristics were not altered significantly. Overall, feed-grade betaine and CSB did not alter growth performance, but did have minor effects on carcass characteristics.     

Evaluation of finishing performance,carcass characteristics,acid-resistant E. coli and total coliforms from steers fed combinations of wet corn gluten feed and steam-flaked corn

Crossbred beef steers (n = 615) were used in a 152-d experiment to compare steam-flaked corn (SFC) diets containing 0, 30, or 60% wet corn gluten feed (WCGF). On d 114 to 118, ruminal and fecal samples were collected from 180 steers and analyzed for pH, VFA, and total and acid-resistant Escherichia coli and coliforms. Acid resistance of E. coli and coliform populations was determined by exposure of the samples for 1 h in pH 2, 4, and 7 citric acid/sodium phosphate buffers. Increasing levels of WCGF linearly decreased total ruminal VFA (P = 0.01) and total fecal VFA (P = 0.06), but linearly increased ruminal and fecal acetate:propionate (P < 0.01) ratio and ruminal and fecal pH (P < 0.05). Feeding increasing WCGF levels resulted in a quadratic response (P < 0.05) with respect to numbers of ruminal E. coli and total coliform populations resistant to pH 4 exposure. Steers fed 30% WCGF had higher (0.7 log units) ruminal E. coli and total coliforms after exposure at pH 4 compared to steers fed 0 or 60% WCGF. Populations of E. coli and total coliforms at pH 2 and 7 were similar for all dietary treatments. Dietary WCGF linearly increased DMI (P = 0.07) and liver abscesses (P = 0.03) and linearly decreased dietary NEg (P = 0.02). Average daily gain and feed efficiencies were greatest when steers were offered 30% WCGF (quadratic, P < 0.05). Dietary manipulations that reduce acid concentrations may not correspond to changes in acid resistance of E. coli and total coliform populations detected in the gastrointestinal tracts of cattle. Moderate levels of WCGF complement SFC finishing diets.     

Correlation between structure and phytotoxic activities of nitrodiphenyl ethers

Various nitrodiphenyl ethers were assayed using a cell-free photosynthetic system and intact microalgae to approach a correlation between chemical structure and their effect upon three biochemical processes: (1) linear photosynthetic electron transport (Hill reaction); (2) photophosphorylation (energy-transfer inhibition by affecting the ATP synthetase); and (3) light-induced peroxidative degradation of thylakoid lipids (formation of short-chain hydrocarbons). Diphenyl ethers with a p-nitro group at one phenyl ring and one or two chloro substituents at the other exhibit energy-transfer inhibition. Analogs with different substituents are ineffective. A moderate electron-transport inhibition is seen with almost all derivatives. The most obvious phytotoxic effect is the occurrence of light-induced peroxidation (of polyunsaturated fatty acids) by p-nitro- and p-nitrosodiphenyl ethers. Substituents such as -OCH₃, -OC₂H₅, -NHC₂H₅, or -COOCH₃, -CONHCH₃ next to the p-nitro group enhance peroxidative activity and are apparently important for stabilization and/or reactivity of a diphenyl ether radical originating through photosynthetic electron flow. Activity is further enhanced by substituents with positive Hammett parameters in ortho or para positions at the phenyl ring not carrying the nitro group.     

In vivo and in vitro metabolism of dexamethasone in the camel

The metabolism of dexamethasone (DXM) in the camel was assessed by in vivo and in vitro techniques. Liver samples were collected at the abattoir from camels of either sex, and microsomes were isolated and characterized as to their protein and haemoprotein content as well as for their ability to metabolise several cytochrome P450 model substrates. The expression of different P450 enzymes was evaluated by means of immunoblotting, and the glucuronidating capacity was assessed with 1-naphthol as the substrate. The activity of 11 beta-hydroxysteroid dehydrogenase type 1 was assayed using metyrapone as a model substrate. To examine the in vitro metabolism of DXM, microsomes were incubated with the corticoid in the presence of either a NADPH-generating system or of uridindiphosphoglucuronic acid. In vivo metabolism of DXM was studied in two male camels, injected with a bolus intravenous dose of DXM (0.2 mg/kg body weight) and DXM metabolites were evaluated in urine samples collected at different times after the administration. DXM and metabolites were extracted using solid phase and liquid-liquid extraction, and analysed by liquid chromatography mass spectrometry (LC/MS) and by LC/MS/MS. Comparative results were obtained by in vitro and in vivo studies. Two phase I metabolites were detected: the major one resulted from reduction of the 3-carbonyl group in ring A and the minor metabolite from ring hydroxylation of ring A. Glucuronidation involved both phase I metabolites as well as the parent compound.     

Depletion of intramuscularly and subcutaneously injected procaine penicillin G from tissues and plasma of yearling beef steers.

Withdrawal periods required when doses of 24,000 IU and 66,000 IU of procaine penicillin G/kg body weight were administered to yearling beef steers by intramuscular injection daily for five consecutive days were investigated. These dosages are in excess of product label recommendations, but are in the range of procaine penicillin G dosages that have been administered for the treatment of some feedlot bacterial diseases. The approved dose in Canada is 7,500 IU/kg body weight intramuscularly, once daily, with a withdrawal period of five days. Based on the tissue residue data from this study, the appropriate withdrawal period is ten days for the 24,000 IU/kg body weight dose and 21 days for the 66,000 IU/kg body weight dose when administered intramuscularly to yearling beef steers. In a related study, 18 yearling beef steers received 66,000 IU of procaine penicillin G/kg body weight administered by subcutaneous injection, an extra-label treatment in terms of both dose and route of administration, typical of current practice in some circumstances. Deposits of the drug were visible at subcutaneous injection sites up to ten days after injection, with more inflammation and hemorrhage observed than for intramuscular injections of the same dose. These results suggest that procaine penicillin G should not be administered subcutaneously at high doses; and therefore a withdrawal period was not established for subcutaneous injection.     

A simple stem taper model with mixed effects for boreal black spruce

We simplified Kozak’s taper model by setting the inflection point at 1.3 m (dbh) without losing accuracy and precision. The simplification was required to facilitate the estimation of the covariance parameters when using a mixed-effects method. This method was necessary to take into account the correlation among multiple diameter measurements on an individual stem. The simple stem taper model was fitted to an extended data set collected across the province of Quebec, Canada. Comparison of the predicted stem taper and the derived stem volume with those obtained using existing models showed a comparable predictive power for the simple model. Including a prediction of the tree random effects based on supplementary diameter measurements of the bole improves the predictive ability of the model around the extra diameter observation. This model offers welcome simplicity as a means of predicting tree taper at coarse resolution for planning tree harvesting.