Delineating site-specific management zones on pasture soil using a probabilistic and objective model and geostatistical techniques

Precision Agriculture - In recent years, different algorithms have been utilised to delineate management zones, areas with similar properties, within agricultural fields. However, there are few...     

Detection of full and limited amphidromous migratory dynamics of fish in Caribbean rivers

All native fishes living in the Caribbean island rivers are considered diadromous but few species have been validated as diadromous. In Guadeloupe (Lesser Antilles) as well as in the other tropical islands, the riverine habitats are subject to strong anthropogenic pressure due to resource modifications or dams. The management of fish biodiversity requires knowledge concerning their life history traits and behaviour that are still unknown for most species at a local scale and at the whole distribution area of the species. In a Guadeloupe river, we inferred the migratory patterns of four freshwater fishes common to Caribbean rivers by the analysis of otolith microchemistry. We found two species Eleotris perniger (Eleotridae) and Sicydium plumieri (Gobiidae) to be completely amphidromous with a marine larval phase and a freshwater adult phase. Agonostomus monticola (Mugilidae) was also found to be amphidromous in this system. The fourth species Gobiesox cephalus (Gobiesocidae) showed elemental ratios suggesting an estuarine larval phase and was defined as “limited amphidromous”. The identification of such life history traits, with limited dispersion abilities, argues for specific management measures in tropical island rivers at a basin scale for the conservation of biodiversity.     

Inactivation of Piscine orthoreovirus

Piscine orthoreovirus infects various salmonid fish species, and the infection is associated with diseases such as heart and skeletal muscle inflammation (HSMI) in farmed Atlantic salmon (Salmo salar). There are no vaccines available or genetically selected resistant hosts that can efficiently control piscine orthoreovirus (PRV) infection. Currently, the only prophylactic measure against PRV is general biosecurity measures aiming to break the transmission cycle. Methods to eradicate infectious virus from contaminated facilities are desirable, but the knowledge on how to inactivate PRV is lacking. A major bottleneck for inactivation studies is the lack of ability to propagate PRV in cell culture. Therefore, in this study we developed an in vivo model for detection of infectious PRV particles after treatment of the virus with inactivation tools such as heat, pH, iodine, UV and commercially available disinfectants. The results show that standard iodine treatment is efficient in inactivation of the virus, and similarly are high and low pH extremes and treatment with Virocid, a commercially available disinfectant. A UV dose of at least 50 mJ/cm² is required for inactivation, and the virus has high resistance against heat treatment.     

Post‐hatching development of the ornamental ‘Red Cherry Shrimp’ Neocaridina davidi (Bouvier, 1904) (Crustacea,Caridea, Atyidae) under laboratorial conditions

The ‘Red Cherry shrimp’, Neocaridina davidi is a small freshwater caridean shrimp living, originally, in various kinds of inland water bodies around Asian countries. This shrimp has reached several countries for ornamental use; however, basic information on the biology of the species is still scarce in the literature. Its early post embryonic development morphology has not yet been described. This paper focused on the production and the development of early post‐hatching stages of N. davidi, its male secondary sexual features, observation of the gonads and the presence of females with embryos. The larval development of N. davidi was almost suppressed as noted by the presence of relatively large‐sized eggs, first stage hatching as a decapodid; and the tail fans were present only from the 2nd post‐hatching stage. A biological important consequence of the presence of this Red Cherry shrimp species in the Neotropics is its potential release into nature, which could cause its rapid dispersion affecting populations of other indigenous caridean freshwater shrimps.     

Dietary roughage sources affect lactating Holstein x Zebu cows under experimental conditions in Brazil: a meta-analysis

Tropical Animal Health and Production - To reduce costs, lactating cows are often fed a higher proportion of roughage and alternative feeds; however, such protocols may not lead to optimal milk...     

Identification and distribution of fungal pathogens associated with seedling blight of rice in the southern United States

Surveys were conducted in the five southern rice-producing states of Arkansas, Louisiana, Mississippi, Missouri and Texas in the United States during the 2018 and 2019 cropping seasons to determine the distribution and pathogenicity of fungal pathogens associated with seedling blight in rice. A total of 349 pathogenic fungal isolates were collected and identified as belonging to four genera: Rhizoctonia solani, Fusarium spp., Sclerotium rolfsii and Marasmius graminum based on morphological characteristics, molecular analysis and Koch's postulates. R. solani (252 out of 349 pathogenic isolates) was the most prevalent fungus isolated from diseased samples. Of the 252 pathogenic R. solani isolates, 245 were further classified as anastomosis group 11 (AG-11) and 7 as AG-4. Isolates of R. solani AG-4 and M. graminum were the most aggressive, with the highest stand loss (63% to 100%) and median disease rating (DR; 5.0), followed by isolates of R. solani AG-11 (stand loss = 4% to 100% and DR = 0.6 to 5.0), Fusarium spp. (stand loss = 26% to 48% and DR = 2.0 to 5.0) and S. rolfsii (stand loss = 33% to 48% and DR = 2.0 to 3.0) in causing seedling blight in rice. R. solani (62% to 83% of total pathogenic isolates) and Fusarium spp. (10% to 24% of total pathogenic isolates) were predominant in all the five states surveyed. S. rolfsii and M. graminum were present only in Louisiana and Texas. The results of this first systematic survey of rice seedling diseases in the southern United States will help develop effective fungicide seed treatment strategies for control of stand loss caused by seedling blight, one of the major factors limiting rice production.     

Effects of two different anesthetic protocols on 64‐MDCT coronary angiography in dogs

Heart rate is a major factor influencing diagnostic image quality in computed tomographic coronary artery angiography (MDCT‐CA), with an ideal heart rate of 60–65 beats/min in humans. The purpose of this prospective study was to compare effects of two different clinically applicable anesthetic protocols on cardiovascular parameters and 64‐MDCT‐CA quality in 10 healthy dogs. Scan protocols and bolus volumes were standardized. Image evaluations were performed in random order by a board‐certified veterinary radiologist who was unaware of anesthetic protocols used. Heart rate during image acquisition did not differ between protocols (P = 1), with 80.6 ± 7.5 bpm for protocol A and 79.2 ± 14.2 bpm for protocol B. Mean blood pressure was significantly higher (P > 0.05) using protocol B (protocol A 62.9 ± 9.1 vs. protocol B 72.4 ± 15.9 mmHg). The R‐R intervals allowing for best depiction of individual coronary artery segments were found in the end diastolic period and varied between the 70% and 95% interval. Diagnostic quality was rated excellent, good, and moderate in the majority of the segments evaluated, with higher scores given for more proximal segments and lower for more distal segments, respectively. Blur was the most commonly observed artifact and mainly affected the distal segments. No significant differences were identified between the two protocols for optimal reconstruction interval, diagnostic quality and measured length individual segments, or proximal diameter of the coronary arteries (P = 1). Findings indicated that, when used with a standardized bolus volume, both of these anesthetic protocols yielded diagnostic quality coronary 64‐MDCT‐CA exams in healthy dogs.     

Influence of race and crossbreeding on casein micelles size

Casein (CN) micelles are colloidal aggregates of protein dispersed in milk, the importance of which in the dairy industry is related to functionality and yield in dairy products. The objective of this work was to investigate the correlation of milk CN micelles diameter from Holstein and Zebu crossbreds with milk composition (protein, fat, lactose, total and nonfat solids and milk urea nitrogen), somatic cell count (SCC), age, lactation stage and production. Average casein micelles diameters of milk samples obtained from 200 cows were measured using photon correlation spectroscopy and multiple regression analysis was used to find relationship between variables. CN micelle diameter, SCC and nonfat solids were different between animals with different Holstein crossbreed ratios, which suggests influence of genetic factors, mammary gland health and milk composition. Overall, results indicate the potential use of CN micelle diameter as a tool to select animals to produce milk more suitable to cheese production.     

Population pharmacokinetics of methadone hydrochloride after a single intramuscular administration in adult Japanese sika deer (Cervus nippon nippon)

ObjectiveTo assess the population pharmacokinetics of methadone in deer.Study designProspective non-randomized experimental trial.AnimalsTwelve healthy adult sika deer (nine males and three females).MethodsDeer received intramuscular administration of racemic methadone hydrochloride at 0.5 mg kg⁻¹ or 1 mg kg⁻¹. Plasma methadone and its metabolite 2-Ethylidene-1,5-Dimethyl-3,3-Diphenyl-Pyrolidine (EDDP) concentrations were determined by validated liquid chromatography coupled to tandem mass spectrometry methods, at times 0, 30 minutes, 1, 2, 3, 4, 5, 6, 8, 12 and 24 hours. Population pharmacokinetics analysis was undertaken using a non-linear mixed effects modelling (NONMEM).ResultsA two-compartment linear disposition model best described observed time-concentration profiles of methadone and EDDP. Population parameter estimates of methadone were elimination clearance (17.3 L hour⁻¹), metabolic clearance (34.6 L hour⁻¹), volume of distribution of compartment 1 (216.0 L) and volume of distribution of compartment 2 (384.0 L). Population parameter estimates of EDDP were elimination clearance (121.0 L hour⁻¹), volume of distribution of compartment 3 (1.08 L) and volume of distribution of compartment 4 (499.5 L). The total clearance and total volume of distribution of methadone and EDDP were 51.9 L hour⁻¹, 121.0 L hour ⁻¹, 600.0 L and 500.6 L, respectively. The methadone terminal elimination half-life was 8.19 hours. No adverse effects were observed after methadone administration.Conclusions and Clinical relevanceFollowing intramuscular injection, methadone was characterized by a large total volume of distribution, high systemic clearance and intermediate terminal half-life in sika deer.