Accuracy of increased large-intestine wall thickness during ultrasonography for diagnosing large-colon torsion in 42 horses

Large-colon torsion is a common cause of colic in horses and has a worse prognosis and higher cost than other causes of surgical colic of the large colon. During large-colon torsion, the colon wall becomes thick due to vascular occlusion. Therefore, we hypothesized that detecting increased colon wall thickness during ultrasonography would be an accurate preoperative test for large-colon torsion. The sample population consisted of 42 horses that were admitted for surgical treatment of colic localized to the large colon. The diagnosis was confirmed at surgery or necropsy examination. Twelve (29%) of these horses were diagnosed with large-colon torsion. Duplicate ultrasonographic measurements of colon wall thickness were made at six abdominal locations and an average measurement was calculated. For four of these six sites, a significant difference (P < 0.005) was detected between horses with and without large-colon torsion. All four tests were moderately sensitive and highly specific for diagnosing large-colon torsion using five decision criteria. Using a ventral abdominal window, a colon wall thickness > or = 9 mm accurately predicted large-colon torsion in eight of the 12 horses (sensitivity, 67%; confidence interval [CI], 36-98%) and correctly predicted that large-colon torsion was absent in 28/28 horses (specificity 100%; CI, 98-100%). Intraobserver repeatability was assessed by evaluating the difference between the first and second measurements obtained, which was < or = 2 mm. Therefore, detecting increased large-colon wall thickness during ultrasonography is a reproducible and accurate preoperative test for large-colon torsion in horses with surgical colic localized to the large colon.     

Comparison of the efficacy of macrocyclic lactone anthelmintics,either singly or in combination with other anthelmintic(s), in nine beef herds in southern NSW

Anthelmintic resistance (AR) is a well-recognized challenge in farmed ruminants. The use of anthelmintics in combination is one of the strategies recommended to slow the rate of AR development. Two studies were undertaken in 2017 and 2019 to assess the efficacy of single-dose macrocyclic lactone (ML) anthelmintic and ML combination drenches. In total, 11 Faecal Egg Count Reduction Trials (FECRTs) were set up in 10 different beef herds, with results available from 10 of those FECRTs (9 herds). AR to a single ML anthelmintic was detected in all 9 herds, with resistance to Cooperia and Haemonchus spp on 9 farms, and resistance to Ostertagia and Trichostrongylus spp on 2 farms. In contrast, for the ML combination anthelmintics, all FECRTs resulted in efficacies of 99%–100%. The results suggest that cattle producers should strongly consider using combination drenches in their herds in preference to single actives.     

Relationships among Puberty,Muscle and Fat,and Liveweight Gain during Mating in Young Female Sheep

Greater depths of muscle are associated with better reproductive performance in ewe lambs, but, in adult ewes, reproductive performance also seems to vary with liveweight gain during the mating period. Therefore, in a large field study with Merino ewe lambs, we tested whether the relationships among eye muscle depth (EMD), fat depth (FAT) and reproductive performance depend on liveweight gain during the mating period. We selected lambs with a wide range in phenotypic values for depths of eye muscle (EMD) and fat (FAT) and assigned them to dietary treatments designed to achieve low (LOW, n = 244) or high (HIGH, n = 237) rates of liveweight gain during a 28‐day mating period. The LOW treatment maintained live weight, whereas the HIGH treatment gained 179 ± 3.8 g/day (p < 0.001). From those ewe lambs that attained puberty, first oestrus was detected at live weight 37.8 ± 0.2 kg and age 232 days. The proportion of ewes that attained puberty increased with EMD (p < 0.01). Ewes from the HIGH treatment were more fertile (pregnant ewes per 100 ewes exposed to rams) and had a higher reproductive rate (foetuses in utero per 100 ewes exposed to rams; p < 0.001) than those from the LOW treatment. Fertility and reproductive rate were positively correlated with weight gain during mating as well as live weight at the start of mating, FAT and EMD (p < 0.05 to <0.001). We conclude that faster growth, due to either extra nutrition during mating or higher phenotypic potential for fat and muscle, will increase reproductive performance in ewe lambs mated at 8 months of age.     

Plant-available water capacity of soils at a regional scale: Analysis of fixed and dynamic field capacities

Estimation of the plant-available water capacity (PAWC) of soils at a regional scale helps in adopting better land use planning, developing suitable irrigation schedules for crops, and optimizing the use of scarce water resources. In the current study, 72 soil profiles were sampled from the Barossa region of South Australia to estimate pedo-transfer functions deduced from easily estimated soil properties. These functions were then used to estimate the fixed (10 and 33 kPa) and dynamic pressure head (h_fc) water contents at field capacity (FC) for minimum drainage flux (0.01 and 0.001 cm d^-1), which serves as the upper boundary for plant-available water in soils. The estimated residual water content was corrected for subsoil constraints, especially the exchangeable sodium percentage (ESP). The results showed that the mean values of h_fc in sand-dominated light and medium textured soils (i.e., sand, loamy sand, sandy loam, and loam) varied in a narrow range (15.8–18.2 kPa), whereas those in the clay-dominated heavy textured soils (i.e., clay loam) showed a wide range (11.3–49.3 kPa). There were large differences in PAWC for dynamic FC (PAWC_fc) and fixed FC at 10 kPa (PAWC₁₀), 33 kPa (PAWC₃₃), and a mix of 10 and 33 kPa (PAWC_10,33) pressure heads depending on soil texture. Normally, the difference between PAWC at 10 kPa and h_fc (∆PAWC₁₀) was positive, whereas that between 33 kPa and h_fc (∆PAWC₃₃) was negative across all sites. Nevertheless, the estimation of PAWC assuming a fixed FC at 10 and 33 kPa pressures (i.e., PAWC_10,33) for sandy, clay, and silty soils reduced the difference between fixed and dynamic pressure PAWCs to < 10% across the region. The estimation of PAWC was improved by incorporating the impact of subsoil constraints, such as high ESP, which was more pronounced for clay and silty soils. These findings demonstrate the inherent inconsistencies between static pressure and flux-based dynamic FC estimations in soils. Soil heterogeneity, intra-texture variability, subsoil constraints, and swell-shrink clays can have great impacts on the water retention capacity in response to dynamic and fixed pressure FC values.     

Esters produced by Chalaropsis thielavioides

Chalaropsis thielavioides, a filamnentous fungus. produces a characteristic ester-like aroma on potato dextrose broth. By gas-liquid chromatographic techniques, the major aroma-producing substances have been identified as isobutyl and ethyl acetate. Lesser amounts of isoamyl acetate, ethanol, and methanol were also present.