Using a GnRH agonist to obtain an index of testosterone secretory capacity in the cockatiel (Nymphicus hollandicus) and sulphur-crested cockatoo (Cacatua galerita)

Objective   Validation of a stimulation test for determining the steroidogenic capacity of the parrot testis. The major aim was to characterise testosterone secretion after injection of a gonadotropin-releasing hormone agonist (GnRHa), then use the test to investigate seasonal reproduction in the male cockatiel.
Procedure   A synthetic GnRHa (buserelin; 8.0 µg of peptide/kg bodyweight) was injected IM into male cockatiels (n = 7) and sulphur-crested cockatoos (n = 3) and serial blood samples collected at 0, 30, 60, 90 and 120 min after administration. Once validated, the technique was subsequently used to examine seasonal changes (23 months) in the testosterone profile of a captive cockatiel population.
Results   Injection of buserelin resulted in a significant increase in the testosterone concentration of cockatiel plasma, with maximal concentrations occurring at approximately 60 (1.33 ± 0.08 ng/mL) to 90 min (1.22 ± 0.08 ng/mL) after injection. Although no clear pattern of seasonal variation in testosterone secretion was detected in cockatiel plasma, samples taken 60 and 90 min after administration showed a significant increase in all seasons. Injection of buserelin in the sulphur-crested cockatoo also resulted in increased testosterone secretion, with maximal concentrations obtained after 90 min.
Conclusion   Buserelin can be used to obtain a reliable index of the prevailing testosterone capacity of the cockatiel and cockatoo testis. With further studies, this test may be incorporated into clinical assessment of reproductive status.     

The Effectiveness and Feasibility of Using Ochre as a Soil Amendment to Sequester Dissolved Reactive Phosphorus in Runoff

Incidental losses of dissolved reactive phosphorus (DRP) to a surface waterbody originate from direct losses during land application of fertilizer, or where a rainfall event occurs immediately thereafter. Another source is the soil. One way of immobilising DRP in runoff before discharge to a surface waterbody, is to amend soil within the edge of field area with a high phosphorus (P) sequestration material. One such amendment is iron ochre, a by-product of acid mine drainage. Batch experiments utilising two grassland soils at two depths (topsoil and sub-soil), six ochre amendment rates (0, 0.15, 1.5, 7.5, 15 and 30 g kg⁻¹ mass per dry weight of soil) and five P concentrations (0, 5, 10, 20 and 40 mg L⁻¹) were carried out. A proportional equation, which incorporated P sources and losses, was developed and used to form a statistical model. Back calculation identified optimal rates of ochre amendment to soil to ameliorate a specific DRP concentration in runoff. Ochre amendment of soils (with no further P inputs) was effective at decreasing DRP concentrations to acceptable levels. A rate of 30 g ochre kg⁻¹ soil was needed to decrease DRP concentrations to acceptable levels for P inputs of ≤10 mg L⁻¹, which represents the vast majority of cases in grassland runoff experiments. However, although very quick and sustained metal release above environmental limits occurred, which makes it unfeasible for use as a soil amendment to control P release to a waterbody, the methodology developed within this paper may be used to test the effectiveness and feasibility of other amendments.     

Evaluation of Amendments to Control Phosphorus Losses in Runoff from Dairy-Soiled Water

Amendments with the potential to reduce phosphorus (P) losses from agricultural grassland arising from the land application of dairy-soiled water (DSW) were investigated. Optimal application rates were studied, and associated costs and feasibility were estimated. First, batch tests were carried out to identify appropriate chemicals or phosphorus sorbing materials to control P in runoff from DSW. Then, the best four treatments were examined in an agitator test. In this test, soil??placed in a beaker??was loaded with DSW or amended DSW at a rate equivalent to 5 mm ha^?1 (the maximum permissible application rate of DSW allowable in a 42-day period in Ireland). The soil was overlain with continuously stirred water to simulate runoff on land-applied DSW. Optimum application rates were selected based on percentage removal of dissolved reactive phosphorus in overlying water and the estimated cost of amendment. The costs of the amendments, per cubic metre of DSW, increased in the order: bottom ash (1.55 ?), alum (1.67 to 1.92 ?), FeCl₂·4H₂O (3.55 to 8.15 ?), and lime (20.31 to 88.65 ?). The feasibility of the amendments, taking into account their cost, potential adverse effects, public perception, and their performance, decreased in the order: alum?>?FeCl₂·4H₂O?>?bottom ash?>?lime. Amendments to DSW could be introduced in critical source areas??areas where high soil test P and direct migration pathways to a receptor overlap.     

The hypoattenuating ocular lens on CT is not always due to cataract formation

Hypoattenuating ocular lenses on CT have been described with cataract formation in humans, however published studies are currently lacking regarding this finding in veterinary patients. The purpose of this retrospective and prospective study was to describe the varying CT appearances of the ocular lens in vivo, and investigate the causes for CT density variations in a population of cats and dogs. A total of 102 canine and feline patients with CT of the head acquired at the authors’ hospital between May 2011 and March 2019 were included. A bilateral hypoattenuating halo surrounding an isoattenuating to mildly hypoattenuating core was described in the ocular lens center of every cat in which a Philips brand proprietary image construction filter was used. A similar but more varied hypoattenuating region was noted in the lenses of 45.8% of dogs where the same filter was applied, as well as 43.8% of dogs with a second, similar filter. Ophthalmic examination of three live cats and one dog with hypoattenuating lenses demonstrated normal lens translucency, excluding the presence of cataract. The effect of different proprietary filters on lens appearance was also described in three fresh cadavers with normal lenses identified on ophthalmic, macroscopic, and microscopic examination. Etiology of the hypoattenuating areas within the ocular lens was not conclusively determined. Recognition that such a variant may be seen in the absence of cataract is important, in order to prevent misdiagnosis.     

Surgical treatment of a second metacarpal bone exostosis with associated desmitis of the body of the suspensory ligament in a horse

This report outlines the diagnosis, surgical treatment and successful outcome following treatment of second metacarpal bone exostosis with concurrent suspensory ligament desmitis, and lameness in a horse. Magnetic resonance imaging was useful in determining the extent of pathology within the suspensory ligament and site of proposed surgical resection. MRI was also utilised as a post-operative tool in determining the timescale for satisfactory healing to enable the horse to return to athletic work.     

Idiopathic sterile pyogranuloma in three domestic cats

Pyogranulomatous inflammation has been extensively described in cats, in particular in cases of feline infectious peritonitis and also associated with Mycobacteria, Actinomyces, Nocardia, Rhodococcus and fungal infections. Idiopathic sterile pyogranulomatous dermatitis has also been described. In this case series we describe the clinical presentation, histopathology and outcome of three cases of feline idiopathic sterile steroid-responsive pyogranuloma with different presentation and different locations of the lesion, but with the common feature of having a mass with no superficial skin involvement.     

Pharmacokinetic profiles of meloxicam after single IV and PO administration in Bilgorajska geese

The purpose of this study was two-fold: I) to determine the pharmacokinetic profile of meloxicam (MLX) in geese after intravenous (IV) and oral (PO) administration and II) to assess tissue residues in muscle, heart, liver, lung, and kidney. Ten clinically normal female Bilgorajska geese were divided into two groups (treated, n = 8; control, n = 2). Group 1 underwent a 3-phase parallel study with a 1-week washout period. In phase I, animals received MLX (0.5 mg/kg) by IV administration; the blood was collected up to 48 hr. In phases II and III geese were treated orally at the same dosage for the collection of blood and tissue samples, respectively. Group 2 served as control. After the extraction procedure, a validated HPLC method with UV detection was used for plasma and organ analysis. The plasma concentrations were quantifiable up to 24 hr after both the administrations. The elimination phase of MLX from plasma was similar in both the administration groups. The clearance was slow (0.00975 L/hr*Kg), the volume of distribution small (0.0487 L/kg), and the IV half-life was 5.06 ± 2.32 hr. The average absolute PO bioavailability was 64.2 ± 24.0%. Residues of MLX were lower than the LOQ (0.1 µg/kg) in any tested tissue and at any collection time. The dosage used in this study achieved the plasma concentration, which provides analgesia in Hispaniolan Amazon parrots for 5 out of 24 hr after PO administration. MLX tissue concentrations were below the LOD of the assay in tissue (0.03 µg/ml). A more sensitive technique might be necessary to determine likely residue concentrations in tissue.     

Consistent responses of yield and resistance of wheat cultivars to the root-lesion nematode,Pratylenchus thornei,in the Australian northern subtropical region,but not in the temperate southern region

To understand the yield response of cereal cultivars to Pratylenchus thornei, eight experiments were conducted within the subtropical northern, and temperate southern grain-producing regions of Australia. Wheat cultivars (Triticum aestivum) ranging from susceptible to moderately resistant to P. thornei were grown in Year 1 to establish a range of population densities. In Year 2 before sowing, P. thornei was quantified in each plot and six cereal cultivars were each grown on a similar range of population densities (average minimum to maximum of 3.4–60.6 P. thornei/g soil); P. thornei was quantified again at harvest. In the four experiments in the northern region there was a significant, negative logarithmic response of yield of the three most intolerant/susceptible cultivars as P. thornei population densities increased (yield decreased 172–479 kg/ha per unit increase in log_e-transformed P. thornei/g soil). The responsiveness of yield to increasing P. thornei population densities diminished as the tolerance and resistance of the cultivars improved. In the southern region, there was no relationship between yield and P. thornei in three experiments and minor, positive increases in one experiment (1.6 kg/ha per unit increase in P. thornei/g soil). Across both regions, the change in P. thornei population densities from sowing to harvest was logarithmic and positive, and generally greatest in the northern region. The contrast of responses of cereal cultivars between the regions, despite similar population densities of P. thornei, is indicative of the influence of the environment particularly on tolerance, therefore management with a regional focus is essential.