High caudal epidural anaesthesia with local anaesthetics or alpha(2)-agonists in calves

The objective of this study was to examine the efficacy of a caudal epidural anaesthesia using lidocaine or xylazine in a high volume for analgesia of the flank, navel and hamstring tendon. Fourteen calves weighing 57.7 +/- 5.1 kg and 37.9 +/- 9.3 (mean +/- SEM) days old were randomly divided into two groups of seven calves each. Calves belonging to the lidocaine group were given a 2% lidocaine solution in the sacrococcygeal vertebral space epidurally at a volume of 0.4 ml/kg (8 mg/kg) body weight (BW). Animals of the xylazine group were administered an epidural anaesthesia with xylazine at a dose of 0.1 mg/kg BW, diluted with a 0.9% saline solution to a corresponding final volume of 0.4 ml/kg BW. Heart rate and respiratory rate were measured and the degree and duration of analgesia was determined by the response to a skin prick with a hypodermic needle over a period of 350 min after epidural injection. After epidural anaesthesia with lidocaine the mean heart rate increased during dorsal recumbency, whereas after xylazine both heart rate and respiratory rate decreased significantly (P < 0.05). The epidural injection of xylazine compared with lidocaine caused longer (P < 0.05) analgesia at the hamstring tendon (mean +/- SEM, 120.7 +/- 29.7 min versus 93.6 +/- 3.5 min) and at the flank (100.7 +/- 24.4 min versus 78.3 +/- 11.1 min). There were no differences in the intensity of analgesia between groups. After xylazine application analgesia at the navel was achieved for 95.0 +/- 14.1 min whereas after lidocaine injection sufficient analgesia at the navel was found in just two of seven calves for 55 and 95 min respectively. Based on above experiences, a second study was performed, in which a combination of xylazine and local anaesthetics was used and the injection volume was increased to prove the efficacy of caudal epidural anaesthesia in 15 calves (26.3 +/- 26.7 days; 57.1 +/- 19.5 kg) submitted to the clinic for regular umbilical surgery. In these cases the xylazine (0.1 mg/kg BW) was diluted with 2% lidocaine (n = 7) or 2% procaine (n = 8) to a corresponding final volume of 0.5-0.6 ml/kg BW. In all cases complete anaesthesia of the surgical area was achieved and no adverse effects were observed. Overall the high volume caudal epidural anaesthesia represents an effective, safe, cheap and easy to perform alternative for anaesthesia of the navel, flank and hamstring tendon in calves without major side effects.     

Survey of 11 western states for heartworm (Dirofilaria immitis) infection, heartworm diagnostic and prevention protocols, and fecal examination protocols for gastrointestinal parasites

Heartworm infection in dogs and cats in the western United States is a fairly new phenomenon, and for this reason it is often considered to be of minimal significance.The purpose of this survey was to collect data from 11 western states (Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, and Wyoming) in an effort to assess awareness of heartworm disease and identify areas in which improvement in understanding is needed. To accomplish this goal, veterinary clinics and hospitals in these states were sent a one-page survey in early 2006. The results of the survey demonstrate that cases of heartworm disease have been reported in all 11 states, illustrating the importance of annual testing and the routine use of preventives.     

Efficacy of famotidine for the prevention of exercise-induced gastritis in racing Alaskan sled dogs

BACKGROUND: Omeprazole reduces the severity of exercise-induced gastritis but not the prevalence of gastric lesions in sled dogs. The frequent feeding of sled dogs during competition likely results in decreased absorption of omeprazole and, thereby, decreased efficacy. HYPOTHESIS: Famotidine, a histamine-2 blocker with good bioavailability in the presence of food, would reduce the incidence and severity of exercise-induced gastric disease in sled dogs. ANIMALS: Sixteen fit Alaskan sled dogs (4 female, 12 male, all intact, age 2-6 years). METHODS: Dogs were randomly assigned to treatment (22 mg famotidine PO q24h) or control groups (n = 8 per group). Famotidine was administered with a meal to the treatment group once daily for 7 days before a challenge and once during exercise. Control dogs were fed an identical diet as the principal group. The 16 dog team completed a 100-mile exercise challenge in 18 hours. A gastroscopy was performed 24 hours after the challenge. The appearance of the mucosa was scored by an individual by using a scoring system. RESULTS: Treatment with famotidine significantly reduced the severity score compared with control (P = .0004). No adverse effects of treatment were reported. CONCLUSIONS AND CLINICAL RELEVANCE: Famotidine is effective in reducing the severity of exercise-induced gastric disease in racing Alaskan sled dogs, with minimal to no adverse effects, and may be recommended for prophylactic use in short distance races.     

Roots in irrigated clay soils: Measurement techniques and responses to rootzone conditions

Summary This paper reviews research carried out at the Griffith Laboratory in Australia over the last decade on techniques for, and results of, observations of roots in irrigated clay soils. Our results emphasise the adaptability of root systems to rootzone conditions. Experiences with techniques for observing roots non-destructively in the field and both non-destructively and destructively in lysimeters are described. We concluded that the minirhizotron technique, applied in the field, was unreliable under our conditions. Horizontal root observation tubes were used in lysimeters to measure root length density (RLD) and to assess whether roots were clumped together or randomly distributed. Destructive sampling and measurement of RLD was used to establish a theoretical relationship between root intercept counts along the tubes and RLD. The application of image analysis to both destructive and non-destructive sampling in the lysimeters is outlined. The non-destructive lysimeter studies showed that roots were significantly clumped. Analysis of root intercept and root hole counts on the faces of sample cubes taken from the lysimeters showed root distribution was anisotropic over the whole soil profile for both safflower and wheat. There were many more roots and root holes present in the sampled soil cubes than was indicated by independent sampling for washed out RLD. Safflower appeared to have a faster turnover of roots than did wheat or maize. Lysimeters, equipped with horizontal root observation tubes, enabled studies to be made of many factors affecting root growth. Soils affect where and how fast roots grow, although there is also a strong species interaction. For example, soybean roots proliferated above a fresh water table in one soil but not in another; wheat had little tendency to proliferate above the water table in either soil. In wet soils, roots cease to grow once soil oxygen levels decrease below 10 mg O₂ l _soil ^-1 . This level should form the basis for soil drainage criteria. In drying soils, roots will grow successively into soil regions containing soil water: the level of adaptation being determined by soil conditions, crop growth stage and level of evaporative demand. The methods of root observation used in our studies have given quantitative assessment of root distribution. However, further research is needed to link horizontal and vertical root distribution and root adaptation more strongly to crop development and soil conditions.     

Effects of soil type on soybean crop water use in weighing lysimeters

Summary Different soils are known to affect the amount and distribution of both available water and roots. Optimising irrigation water use, especially when shallow water-tables are present requires accurate knowledge of the root zone dynamics. This study was conducted to determine the effect of two soil types on root growth, soil water extraction patterns, and contributions of a water-table to crop evaporation (E). Two weighing lysimeters (L1 and L2) with undisturbed blocks of soil were used. The soil in L1 had higher hydraulic conductivity and lower bulk density than that in L2. Well watered conditions were maintained by irrigation for the first 110 days from sowing (DFS). Root length density (RLD) was calculated from observations made in clear acrylic tubes installed into the sides of the lysimeters. Volumetric soil water contents were measured with a neutron probe. A water-table (EC = 0.01 S m^-1) was established 1 m below the soil surface 18 DFS. RLD values were greater in L1 than L2 at any depth. In L1, maximum RLD values (3 × 10⁴ m m^-3) were measured immediately above the water-table at physiological maturity (133 DFS). In L2, maximum RLD values (1.5 × 10⁴ m m^-3) were measured at 0.42 m on 120 DFS and few roots were present above the water-table. From 71 to 74 DFS, 55 and 64% of E was extracted from above 0.2 m for L1 and L2, respectively. In L2, extraction was essentially limited to the upper 0.4 m, while L1 extraction was to 0.8 m depth. Around 100 DFS the water-table contributed 29% (L1) and 7% (L2) of the water evaporated. This proportion increased rapidly as the upper soil layers dried following the last substantial irrigation 106 DFS. Over the whole season the water-table contributed 24% in L1 and 6.5% in L2 of total E.     

Impact of cash crop cultivation on household income and migration decisions: Evidence from low-income regions in China

This study examines the impact of cash crop cultivation on household income and migration decisions, using survey data collected from low-income regions in China. Given farmers decide themselves whether to cultivate cash crops, an endogenous treatment regression model that accounts for potential selection bias issue is used to analyze the data. The empirical results show that cash crop cultivation exerts a positive and statistically significant impact on household income, but it does not affect household migration decisions significantly. The disaggregated analyses reveal that cash crop cultivation significantly increases farm income but decreases off-farm income.     

Meta-analysis of fungicide efficacy on soybean target spot and cost–benefit assessment

Target spot of soybean has spread in Brazil, the southeastern United States and Argentina in the last decade. A collaborative network of field Uniform Fungicide Trials (UFT) in Brazil was created in 2011 to study the target spot control efficacy of fungicides, including azoxystrobin + benzovindiflupyr (AZ_BF), carbendazim (CZM), fluxapyroxad + pyraclostrobin (FLUX_PYRA), epoxiconazole + FLUX_PYRA (EPO_FLUX_PYRA), mancozeb (MZB) and prothioconazole + trifloxystrobin (PROT_TRIF). Network meta-analysis was used to conduct a quantitative synthesis of UFT data collected from 2012 to 2016 and to evaluate the effects of disease pressure (DP, low ≤ 35% target spot severity in the nontreated control < high) and year of experiment on the overall mean efficacy and yield response to each of the tested fungicides. Based on mean percentage control of target spot severity, the tested fungicides fall into three efficacy groups (EG): high EG, FLUX_PYRA (76.2% control relative to the nontreated control) and EPO_FLUX_PYRA (75.7% control); intermediate EG, PROT_TRIF (66.5% control) and low EG, MZB (49.6% control), AZ_BF (46.7% control) and CZM (32.4% control). DP had a significant effect on yield response. At DP_Low, the highest response was due to PROT_TRIF (+342 kg ha⁻¹, +12.8%) and EPO_FLUX_PYRA (+295.5 kg ha⁻¹, +11.2%), whereas at DP_High, EPO_FLUX_PYRA and FLUX_PYRA outperformed the other treatments, with yield responses of 503 kg ha⁻¹ (+20.2%) and 469 kg ha⁻¹ (+19.1%), respectively. The probability of a positive return on fungicide investment ranged from 0.26 to 0.56 at DP_Low and from 0.34 to 0.66 at DP_High.     

Expression of genes involved in the early immune response at the distal segment of the gut in Atlantic cod, Gadus morhua L. after vaccination with a bacterial antigen

The gastro-intestinal tract serves as the route of infection of most bacterial pathogens in fish, and the immune response genes in the gut produce substances that provide an initial defense during pathogen invasion. The expression of some genes involved in antibacterial defense, cell-mediated immunity and inflammation in the distal intestine of Atlantic cod, Gadus morhua L., was investigated following intraperitoneal vaccination with heat-killed Vibrio anguillarum. Tissue samples of the distal intestine were collected at 0, 1, 3, 7 and 10 days post-vaccination (dpv) and processed for semi-quantitative RT-PCR analyses. Expression of the bactericidal/permeability-increasing protein/lipopolysaccharide-binding protein (BPI/LBP), g-type lysozyme, non-specific cytotoxic cell receptor protein-1 (NCCRP-1) and interleukin-8 (IL-8) significantly increased during the early stages post-vaccination, that is, 1–3 dpv, followed by a decrease in their expression returning to their initial levels. Transferrin and apolipoprotein A-I, although weakly expressed in the distal intestine, also increased in the vaccinated fish. Interleukin-1β (IL-1β) was significantly decreased in its expression level relative to the PBS-injected fish at 3 and 7 dpv. The expression of these immune-related genes in the distal intestine as a result of vaccination provides valuable information on the mechanisms of gut immunity in the fish against pathogenic bacteria, particularly during the early stages of infection.     

Effect of Silver Carp Hypophthalmichthys molitrix and Freshwater Mussel Elliptio complanata Filtration on the Phytoplankton Community of Partitioned Aquaculture System Units

Growers produce over 2.8 million kg of catfish (over $350 million wholesale revenue) annually in the United States. The microbiology of the phytoplankton community in culture water affects the growth and flavor of the catfish and is a consideration for growers. Filter feeders, like silver carp and freshwater mussels, in controlled growth systems are used to adjust the phytoplankton species. Our goal was to successfully control the algal populations with filter feeders in catfish production. We used silver carp Hypophthalmichthys molitrix as a filter feeder in Partitioned Aquaculture System (PAS) water. Silver carp completely eliminated the cyanobacteria Microcystis by size and biovolume reduction. This created the desired effect of small green algae dominating the algal community. A significant but opposite change was observed when freshwater mussels Elliptio complanata filtered PAS water resulting in Microcystis biovolume and size dominance in the PAS; a less desirable algal community. This study also showed an immediate shift in the phytoplankton community when silver carp and mussels were interchanged between PAS waters. The size-selective filtration by the two filter-feeding taxa was important in determining the composition of the PAS phytoplankton community, and it was apparent that filtration with silver carp successfully depleted undesirable algae.