Spatial Variability of Turbulent Mixing in the Abyssal Ocean

Ocean microstructure data show that turbulent mixing in the deep Brazil Basin of the South Atlantic Ocean is weak at all depths above smooth abyssal plains and the South American Continental Rise. The diapycnal diffusivity there was estimated to be less than or approximately equal to 0.1 x 10(-4) meters squared per second. In contrast, mixing rates are large throughout the water column above the rough Mid-Atlantic Ridge, and the diffusivity deduced for the bottom-most 150 meters exceeds 5 x 10(-4) meters squared per second. Such patterns in vertical mixing imply that abyssal circulations have complex spatial structures that are linked to the underlying bathymetry.     

Suppression of ovarian progesterone production in dairy cows using an implant of GnRH-agonist (deslorelin) for the purpose of evaluating progesterone metabolism

OBJECTIVE: To evaluate the potential of an implant of a GnRH-agonist (deslorelin) to create a progesterone free animal suitable for studying progesterone (P4) metabolism in intact cows by measuring blood P4 and faecal P4 metabolites. METHODS: Experiment 1: Eighteen non-lactating cycling Holstein-Friesian cows, 4 to 7 years old, were allocated to one of three groups to study plasma P4 concentrations preceding an intravaginal insert. These groups comprised: i) a deslorelin group (GnRH-agonist implanted); ii) a PGF group receiving two injections of prostaglandin (PGF2alpha) 12 days apart; and, iii) an ovariectomised (OVX) group. An intravaginal device (CIDR) was inserted into the vagina of each animal and left in place for 11 days. Plasma P4 concentrations were measured during the study period. Experiment 2: Twelve non-lactating cycling Holstein-Friesian cows, 4 to 7 years old, were allocated to two groups: i) a deslorelin group (GnRH-agonist implanted); and ii) an ovariectomised group. Plasma P4 and faecal P4 metabolites (20-oxo-pregnanes, 20alpha-OH and 20beta-OH) were monitored for a period of 5 weeks. RESULTS: Experiment 1: Average plasma P4 concentration did not differ between the three groups (1.28, 1.43 and 1.55 ng/mL for deslorelin, OVX and PGF cows, respectively, P = 0.8) during the period of supplementation. Experiment 2: There was no difference in plasma P4 (mean plasma P4 < 0.02 ng/mL, P = 0.9) and faecal P4 metabolites between deslorelin and OVX cows 2 weeks after the implantation (P = 0.7). CONCLUSIONS: These data showed that a GnRH-agonist (deslorelin) implant may be used as an alternative to ovariectomy to create a progesterone free animal suitable for studying the metabolism of administered P4.     

EARLY POSTOPERATIVE MAGNETIC RESONANCE IMAGING FINDINGS IN FIVE DOGS WITH CONFIRMED AND SUSPECTED BRAIN TUMORS

Early postoperative neuroimaging has been performed in people for over 20 years to detect residual brain tumor tissue and surgical complications. The purpose of this retrospective study was to describe characteristics observed using early postoperative magnetic resonance imaging in a group of dogs undergoing craniotomy for brain tumor removal. Two independent observers came to a consensus opinion for presence/absence of the following MRI characteristics: residual tumor tissue; hemorrhage and ischemic lesions; abnormal enhancement (including the margins of the resection cavity, choroid plexus, meninges) and signal intensity changes on diffusion‐weighted imaging. Five dogs were included in the study, having had preoperative and early postoperative MRI acquired within four days after surgery. The most commonly observed characteristics were abnormal meningeal enhancement, linear enhancement at margins of the resection cavity, hemorrhage, and a thin rim of hyperintensity surrounding the resection cavity on diffusion‐weighted imaging. Residual tumor tissue was detected in one case of an enhancing tumor and in one case of a tumor containing areas of hemorrhage preoperatively. Residual tumor tissue was suspected but could not be confirmed when tumors were nonenhancing. Findings supported the use of early postoperative MRI as a method for detecting residual brain tumor tissue in dogs.     

SnakeMap: four years of experience with a national small animal snake envenomation registry

SnakeMap is a national cloud-based, veterinary snakebite registry. It was designed to prospectively collect data of the clinical circumstances and temporospatial information on cases of snake envenomation in dogs and cats. We herein introduce the project and summarise the data from the first 4 years of SnakeMap. The registry is a veterinary community-based online database allowing case entry from veterinary hospitals across Australia. Registry data comprise hospital characteristics, patient characteristics, envenoming snake type, treatment and outcome variables, including time and geolocation of the snake bite. We present summative information on select key variables from the SnakeMap registry (1 July 2015 to 30 June 2019). Twenty-eight hospitals from 6 states/territories entered 624 cases into the registry, including 419 dogs (67%) and 205 cats (33%). Bite time was available in 216 animals of which 90 (42%) were reported to be bitten in the 3 hours between 03:00 pm and 05:59 pm; median bite to presentation interval was 60 (interquartile range [IQR] 30, 211) minutes in dogs and 95 (IQR 41, 238) minutes in cats. Bites occurred in the owner's yard in 356 dogs (85%) and 53 cats (26%). A snake venom detection kit was used in 172 cases (28%) and antivenom was administered in 523 cases (85%). Most animals (n = 534, 88%) survived to discharge (median hospitalisation of 25 [IQR 16, 62] hours). SnakeMap effectively collects relevant clinical data from dogs and cats with presumed snake bite and provides locally specific information on the epidemiology of snake envenomation in small animals.     

Theileria orientalis: a review

Theileria orientalis (also known historically as T. sergenti and T. buffeli) is responsible for benign or non-transforming theileriosis, and exerts its major effect through erythrocyte destruction. The life cycle of T. orientalis is essentially similar to that of other Theileria species, except that the schizonts do not induce transformation and fatal lymphoproliferation. The pathogenesis of anaemia as a result of infection is not clearly established and may be multifaceted. Clinical signs of weakness, reluctance to walk and abortion are early but non-specific indications of disease, particularly if accompanied by a history of cattle being moved. Physical examination may reveal pallor (pale eyes, vaginal mucosa), pyrexia, and elevated heart and respiratory rates. T. orientalis is an economically important parasite of cattle in New Zealand, Australia and Japan, especially where naïve animals are introduced into an endemic area or in animals under stress. Increased awareness of the risks posed by the parasite is required to enable management practices to be implemented to minimise its impact.     

Utilization of nitrogen and energy by Holstein steers fed formaldehyde- and formic acid-treated alfalfa or orchardgrass silage at two intakes

Our objective was to measure the utilization of energy (E) and N by Holstein steers when fed alfalfa and orchardgrass silages offered at 65 and 90 g DM/kg live weight (LW).75 daily. Twelve steers adapted to the Beltsville respiration chambers were assigned to three Latin squares with 42-d periods. Steers in one square had permanent catheters in the portal and two mesenteric veins. Energy and N balance were measured during a 7-d collection of feces and urine that included a 3-d measurement of respiratory exchange. Energy and N variables were not different between catheterized and uncatheterized steers. Apparent digestibilities of DM, OM, CP, neutral detergent solubles and permanganate lignin were higher (P less than .01) and digestibilities of NDF and ADF, hemicellulose and cellulose were lower (P less than .01) for steers consuming alfalfa compared to orchardgrass silage. When fed alfalfa, steers' daily gross energy intake, DE, urine energy, ME, heat production and tissue energy retention were greater (P less than .01) and fecal energy losses were less (P less than .01) than when they were fed orchardgrass. Partial efficiency of ME use for tissue energy (TE) was greater (P less than .01) for steers when fed alfalfa (46.1%) than when fed orchardgrass (35.6%). Apparent ME (kcal/LW.75) required for maintenance of TE was similar for steers when fed alfalfa (133.9) and orchardgrass (131.2) silages. Nitrogen retention (g/d) was 48% greater (P less than .01) for steers when fed alfalfa (30.6) than when fed orchardgrass (20.7). This study demonstrates that steers used ME from alfalfa more efficiently for TE deposition than ME from orchardgrass.