The pathology of Johne''s disease in sheep

The clinical, gross and histopathological findings in 50 sheep affected with Johne's disease are described. Clinically 90% were emaciated and 20% showed severe diarrhoea. On necropsy there was thickening of the walls of the intestines, particularly of the ileum, caecum and less frequently the jejunum, but in 36% of sheep the changes were only mild. Histologically there was a granulomatous enteritis, typhlitis and colitis, with the most severe changes in the terminal ileum. High numbers of acid-fast organisms were present in the terminal ileum in over 70% of sheep. Mycobacterium paratuberculosis was cultured from only 8% of the sheep examined.     

Pharmacokinetics and pharmacodynamics of three formulations of firocoxib in healthy horses

The objectives of this study were to compare the pharmacokinetics and COX selectivity of three commercially available formulations of firocoxib in the horse. Six healthy adult horses were administered a single dose of 57 mg intravenous, oral paste or oral tablet firocoxib in a three‐way, randomized, crossover design. Blood was collected at predetermined times for PGE₂ and TXB₂ concentrations, as well as plasma drug concentrations. Similar to other reports, firocoxib exhibited a long elimination half‐life (31.07 ± 10.64 h), a large volume of distribution (1.81 ± 0.59L/kg), and a slow clearance (42.61 ± 11.28 mL/h/kg). Comparison of the oral formulations revealed a higher C_max, shorter T_max, and greater AUC for the paste compared to the tablet. Bioavailability was 112% and 88% for the paste and tablet, respectively. Maximum inhibition of PGE₂ was 83.76% for the I.V. formulation, 52.95% for the oral paste formulation, and 46.22% for the oral tablet formulation. Pharmacodynamic modeling suggests an IC₅₀ of approximately 27 ng/mL and an IC₈₀ of 108 ng/ mL for COX2 inhibition. Inhibition of TXB₂ production was not detected. This study indicates a lack of bioequivalence between the oral formulations of firocoxib when administered as a single dose to healthy horses.     

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.     

7500 years of prehistoric footwear from arnold research cave, missouri

Accelerator mass spectrometer dating of an assemblage of fibrous and leather footwear from Arnold Research Cave in central Missouri documents a long sequence of shoe construction by prehistoric Midwestern peoples, beginning perhaps as early as 8300 calendar years before the present (cal years B.P.). An earlier fibrous sandal form dates from 8325 to 7675 cal years B.P., and later fibrous or leather slip-ons span the period from 5575 to 1070 cal years B.P. The assemblage adds to a growing picture of the highly varied nature of prehistoric footwear production in the United States throughout the Holocene.     

Frost response in wheat and early detection using proximal sensors

Frost can significantly reduce production of field crops grown in Mediterranean‐type environments, where significant economic losses for Australian wheat occur annually. If non‐destructive sensors could make rapid, spatial assessment of frost damage, this could limit economic losses through timely management decisions. This paper reports on a methodology for imposing frost treatments to wheat under field conditions and the utility of canopy reflectance data for detecting early crop damage. Purpose‐built chambers using stepped additions of dry ice allowed for a range of frost scenarios to be tested when applied at wheat heading and anthesis. For frost treatments applied at anthesis, grain number and yield were reduced by 8.8% and 7.2%, respectively, for every degree Celsius below zero (down to ?4°C). This effect was additive over two consecutive nights. For cold load equivalent, there was a 2.2% and 1.9% reduction in grain number and yield, respectively, per °C hr (below 0°C). For wheat, spectral indices PRI and NDVI (reflectance) and FRF_G and SFR_G (fluorescence) showed significant relationships, with cold load applied for heading treatments. Next steps include targeting frost intensities equivalent to cold loads between 20 and 80°C hr and testing the utility of these proposed indices in a commercial paddock setting.     

Early harvest and ensilage of forage sorghum infected with ergot (Claviceps africana) reduces the risk of livestock poisoning

Sorghum ergot produces dihydroergosine (DHES) and related alkaloids, which cause hyperthermia in cattle. Proportions of infected panicles (grain heads), leaves and stems were determined in two forage sorghum crops extensively infected 2 to 4 weeks prior to sampling and the panicles were assayed for DHES. Composite samples from each crop, plus a third grain variety crop, were coarsely chopped and half of each sealed in plastic buckets for 6 weeks to simulate ensilation. The worst-infected panicles contained up to 55 mg DHES/kg, but dilution reduced average concentrations of DHES in crops to approximately 1 mg/kg, a relatively safe level for cattle. Ensilation significantly (P = 0.043) reduced mean DHES concentrations from 0.85 to 0.46 mg/kg.