The Influence of a Particle Separation Technology on the Generation of Airborne Particles from Different Roughages and Bedding Materials Used for Horses

Four different types of bedding materials (wheat straw, wood shavings, hemp shives, flax shives) and two roughages (hay, haylage) were treated using an air-driven particle separation technology. The airborne particle and mold generation of both treated and untreated samples were then analyzed under standardized laboratory conditions. In addition, samples of all the treated materials were stored for 8 weeks either in a pressed or incoherent form and then analyzed again for their ability to generate airborne particles. The airborne particle concentrations were detected online with the gravimetrically measuring analyzer tapered element oscillating microbalance (TEOM) 1400a that was equipped successively with different inlets to measure the particle fractions PM₂₀, PM₁₀, PM_2.5, and PM_1.0 (PM = Particulate matter). The particle separation resulted in a reduction in the airborne particle (PM₂₀) generation in all materials: hay 49.16 to 22.79 mg/m³ (53.6%), haylage 28.57 to 25.04 mg/m³ (12.3%), wood shavings 141.68 to 15.04 mg/m³ (89.4%), wheat straw 143.08 to 22.97 mg/m³ (83.9%), flax 135.11 to 53.31 mg/m³ (60.5%), and hemp 63.67 to 17.64 mg/m³ (72.3%). The 8-week storage of the treated materials as compressed materials led to a renewed significant increase in the airborne particle (PM₁₀) concentration in the haylage (+29.9%), wheat straw (+104.0%), wood shavings (+40.4%), and hemp shives (+30.7%). Storage of the incoherent materials caused a significant increase in these particles only in the wheat straw (+44.2%). The separation treatment reduced the mold production by 92.4% in the wood shavings, 88.0% in the wheat straw, and 85.8% in the hay.     

Generation of Airborne Particles from Different Bedding Materials Used for Horse Keeping

Among other factors (eg, feed), bedding material has an important effect on stable air quality with respect to airborne particle formation. This study was designed to establish which material is suited to create an improved stable environment for horses. First, the following materials were analyzed under standardized conditions in a laboratory experiment: wheat straw, dry wood shavings, hemp shives, linen shives, wheat straw pellets, paper cuttings (unprinted newspaper). The second investigation was carried out under in situ conditions in which three of these bedding materials (wheat straw, wood shavings, and straw pellets) were analyzed under practical conditions. In both experiments, airborne particle concentrations were detected online with the gravimetrically measuring analyzer TEOM 1400a (Rupprecht & Patashnick Co., Franklin, MA). In the laboratory experiment, the TEOM was equipped successively with different inlets to measure the particle fractions PM₁, PM_2.5, PM₁₀, and PM₂₀. During the in situ experiment, only the fraction PM₁₀ was detected. In the laboratory experiment, hemp and linen had the highest generation of airborne particles in all fractions. The lowest particle generation was detected with straw pellets. Results of the in situ investigation supported results of the laboratory experiment with respect to mean particle generation of straw pellets. With an average of 111.2 ± 149.2 μg/m³, it was significantly lower than the mean particle generation of wheat straw with 227.5 ± 280.8 μg/m³. The particle generation of wood shavings had an average of 140.9 ± 141.9 μg/m³ and also was significantly lower than the generation by wheat straw. An activity-correlated variation of particle concentrations was found. In conclusion, taking both experiments into consideration, straw pellets seemed to be suitable for horse stables, to promote an improvement in the stable climate in relation to airborne particle formation.     

Reduction of Ammonia Emissions from Stored Laying Hen Manure Through Topical Application of Zeolite,Al+ Clear,Ferix-3, or Poultry Litter Treatment

Practical means to decrease aerial emissions will enhance the ability of the US egg industry to improve environmental stewardship while continuing to provide consumers safe and affordable eggs. Ammonia emissions from manure-belt laying hen houses have been shown to be less than 10% of the emissions from high-rise counterparts where manure is stored in-house for a year. However, on-farm manure storage for manure-belt houses also emits NH₃, which is a part of the total farm emissions. Nevertheless, treating manure in storage sheds to decrease NH₃ emissions may be more readily implemented than treatment inside the layer houses because of potential bird health concerns and possible detrimental effects of the treatment on the housing equipment. The laboratory-scale experiments reported here examined the efficacy of 4 commercially available treatment agents, topically applied to laying hen manure at 3 different dosages, in decreasing NH₃ emissions from the manure storage. The treatment agents included zeolite, 2 forms of Al⁺ Clear (aluminum sulfate, 48.5% liquid and granular), Ferix-3 (ferric sulfate), and Poultry Litter Treatment (PLT, sodium bisulfate). All the tested agents showed appreciable NH₃ emission reduction of 33 to 94%. In all cases, the greatest application dosage provided little additional NH₃ reduction as compared with the medium dosage (P > 0.70). Comparison among the dry granular Al⁺ Clear, Ferix-3, and PLT in reduction of NH₃ emission over a 7-d manure storage period showed no significant difference when the agents were applied at 0.5 kg/m² of manure surface area (P = 0.40) but greater reduction for Al⁺ Clear (92 ± 3%) and Ferix-3 (90 ± 1%) as compared with PLT (81 ± 2%) when applied at 1.0 kg/m² (P < 0.01). Further field verification tests of the laboratory-scale findings are warranted.     

The effect of midazolam on the end-tidal concentration of isoflurane necessary to prevent movement in dogs

ObjectiveTo determine the possible additive effect of midazolam, a GABA_A agonist, on the end-tidal concentration of isoflurane that prevents movement (MAC_NM) in response to noxious stimulation.Study designRandomized cross-over experimental study.AnimalsSix healthy, adult intact male, mixed-breed dogs.MethodsAfter baseline isoflurane MAC_NM (MAC_NM-B) determination, midazolam was administered as a low (LDS), medium (MDS) or high (HDS) dose series of midazolam. Each series consisted of two dose levels, low and high. The LDS was a loading dose (Ld) of 0.2 mg kg^?1 and constant rate infusion (CRI) (2.5 μg kg^?1 minute^?1) (LDL), followed by an Ld (0.4 mg kg^?1) and CRI (5 μg kg^?1 minute^?1) (LDH). The MDS was an Ld (0.8 mg kg^?1) and CRI (10 μg kg^?1 minute^?1) (MDL) followed by an Ld (1.6 mg kg^?1) and CRI (20 μg kg^?1 minute^?1) (MDH). The HDS was an Ld (3.2 mg kg^?1) and CRI (40 μg kg^?1 minute^?1) (HDL) followed by an Ld (6.4 mg kg^?1) and CRI (80 μg kg^?1 minute^?1) (HDH). MAC_NM was re-determined after each dose in each series (MAC_NM-T).ResultsThe median MAC_NM-B was 1.42. MAC_NM-B did not differ among groups (p >0.05). Percentage reduction in MAC_NM was significantly less in the LDS (11 ± 5%) compared with MDS (30 ± 5%) and HDS (32 ± 5%). There was a weak correlation between the plasma midazolam concentration and percentage MAC_NM reduction (r = 0.36).Conclusion and clinical relevanceMidazolam doses in the range of 10–80 μg kg^?1 minute^?1 significantly reduced the isoflurane MAC_NM. However, doses greater than 10 μg kg^?1 minute^?1 did not further decrease MAC_NM indicating a ceiling effect.     

Generation of Airborne Particles from Horse Feeds Depending on Type and Processing

Among other factors (eg, bedding material, roughage), feed has an important effect on the airborne particle concentration in the stable air, in particular directly in the breathing zone of the horse during feeding. Therefore, this study was designed to analyze and compare the generation of different airborne particle fractions of diverse feed types and feed processing techniques under standardized laboratory conditions. Oats and barley as well as two commercially formulated ready-prepared pellets and two different commercially formulated ready-prepared mixes were analyzed. Oats were subjected to four different forms of processing (whole uncleaned, whole cleaned, rolled uncleaned, rolled cleaned), barley was subjected to steam flaking in addition to the same forms of processing as oats. In total, 13 feeds were analyzed. Airborne particle concentrations were detected online with a gravimetrically measuring analyzer that was equipped successively with different inlets to measure the particle fractions PM 1, PM 2.5, PM 10, and PM 20. The measurements were carried out in a closed chamber (1 × 1 × 1.5 m) including a bowl (diameter = 0.5 m), which simulated the trough. The sample inlet was situated at a height of 1.0 m above the bowl. Rolling oats and barley led to a significantly increased generation of the PM 20 fraction and a significantly decreased generation of the PM 2.5 fraction. The mechanical cleaning of oat and barley brings a clear decrease in dust generation from straights whether they are left whole or are rolled after cleaning. A considerable reduction in dust generation can be achieved if steam-flaked barley or commercially prepared feeds are used.     

Chemical composition,in vitro gas production,methane production and fatty acid profile of canola silage (Brassica napus) with four levels of molasses

The objective of this study was to investigate the effect of four levels of molasses on chemical composition, in vitro digestibility, methane production and fatty acid profile of canola silages. A canola (Brassica napus var. Monty) crop was established in a small-scale agricultural farm and harvested 148 days after sowing. Four levels of molasses were tested with respect to the fresh weight (1.5 kg); these were 1% (CS-1), 2% (CS-2), 3% (CS-3) and 4% (CS-4) molasses, and 0% molasses (CS-0) was included as a control. A total of 45 microsilages were prepared using PVC pipes (4 in. of diameter × 20 cm of length), and the forage was compressed using a manual press. The effects of control and treatments were tested using the general linear model Y?=?μ?+?T_i?+?E_ij. The linolenic acid (C18:3n3), palmitic acid (C16:0) and linoleic acid methyl ester (C18:2n6c) accounted for 30%, 21% and 10.5% of total fatty acids, respectively; the fermentation parameters and in vitro methane production were not affected (P?>?0.05) by treatments; in vitro digestibility decreased significantly (P?<?0.05) as the level of molasses increased. It was concluded that CS-4 improved the DM content by 9% and showed high content of linolenic acid methyl ester. The gross energy of canola silages could favour the oleic acid methyl ester.

     

Effect of oat particle size on energy and nutrient utilization in growing pigs

An experiment was conducted to determine the energy content of oats and to investigate the effects of oat particle size on nutrient and energy balance in growing pigs. Eighteen barrows (23.56 ± 0.94 kg initial body weight) were randomly assigned to one of the three dietary treatments with six replicates per treatment. Whole oats were ground with a hammermill fitted with 4.8- and 3.2-mm screens to make coarse and medium particle size oats, respectively. Medium oats were further ground with a rotary steel cutting grinder fitted with a 2.0-mm screen, and the further ground oats were mixed with medium oats in a 1:3 ratio to make fine oats. Three experimental diets consisted of 96.3% of the coarse, medium, or fine oats as a sole source of energy were used. Pigs were fed diets for 16 d, including 10 d for adaptation and 6 d for total fecal and urine collection. Pigs were then moved into indirect calorimetry chambers to determine 24-h heat production and 12-h fasting heat production. All data were analyzed using the MIXED procedure of SAS with the individual pig as the experimental unit. The geometric mean particle sizes for coarse, medium, and fine oats were 765, 619, and 569 μm, respectively. Pigs fed the medium oats diet tended to have (P < 0.10) greater apparent total tract digestibility (ATTD) of starch, neutral detergent fiber, and gross energy than those fed coarse oats diet. The medium oats diet contained greater (P < 0.05) digestible energy (DE), metabolizable energy (ME), and net energy (NE) than the coarse oats diet. Pigs fed the fine oats diet had lower (P < 0.05) ATTD of Ca and P than those fed the coarse oats diet. The DE, ME, and NE contents of fine oats were comparable with those of coarse oats. The determined NE contents for coarse, medium, and fine oats were 2,335, 2,615, and 2,521 kcal/kg on a dry matter basis, respectively. The NE content in medium oats was greater (P < 0.05) than the NE values predicted using published equations. In conclusion, it was suggested to grind whole oats for 619 μm concerning energy utilization. Further grinding to 569 μm reduces Ca and P digestibility.     

Defoliation Effects On Bromus Tectorum Seed Production: Implications For Grazing

Cheatgrass (Bromus tectorum L.) is an invasive annual grass that creates near-homogenous stands in areas throughout the Intermountain sagebrush steppe and challenges successful native plant restoration in these areas. A clipping experiment carried out at two cheatgrass-dominated sites in eastern Oregon (Lincoln Bench and Succor Creek) evaluated defoliation as a potential control method for cheatgrass and a seeding preparation method for native plant reseeding projects. Treatments involved clipping plants at two heights (tall = 7.6 cm, and short = 2.5 cm), two phenological stages (boot and purple), and two frequencies (once and twice), although purple-stage treatments were clipped only once. Treatments at each site were replicated in a randomized complete block design that included a control with no defoliation. End-of-season seed density (seeds · m⁻²) was estimated by sampling viable seeds from plants, litter, and soil of each treatment. Unclipped control plants produced an average of approximately 13 000 and 20 000 seeds · m⁻² at Lincoln Bench and Succor Creek, respectively. Plants clipped short at the boot stage and again 2 wk later had among the lowest mean seed densities at both sites, and were considered the most successful treatments (Lincoln Bench: F_6,45 = 47.07, P < 0.0001; Succor Creek: F_6,40 = 19.60, P < 0.0001). The 95% confidence intervals for seed densities were 123–324 seeds · m⁻² from the Lincoln Bench treatment, and 769–2 256 seeds · m⁻² from the Succor Creek treatment. Literature suggests a maximum acceptable cheatgrass seed density of approximately 330 seeds · m⁻² for successful native plant restoration through reseeding. Thus, although this study helped pinpoint optimal defoliation parameters for cheatgrass control, it also called into question the potential for livestock grazing to be an effective seed-bed preparation technique in native plant reseeding projects in cheatgrass-dominated areas.     

Quantitative Evaluations of the Tubular Epithelium in the Testis of the Fallow Deer (Dama dama)

Contents: The quantitative morphology of the seminiferous epithelium was studied in 10 testes of 16- to 17-monthsold fallow bucks (Dama dama). Seminiferous tubules constitute 77.2% of the testicular parenchyma and amount to a total length of 400–750 m per testis. According to varying cell associations 6 different stages can be observed during the spermatogenic cycle. The average tubular diameter varies between 215 μm (stage 1) and 230 μm (stage 8), the epithelial height between 67.6 μm in stage 3 and 71.9 μm in stage 8 when spermiation occurs. From primary spermatocytes during the prophase of the first meiotic division preleptotenes have smallest nuclear (203.7 μm³) and cellular (469.1 μm³) volumes, whereas late diplotenes show a nuclear volume of 846.7μm³ and a cellular volume of 3440.5 μm³, that is an increase of more than 4 times for the nucleus and more than 7 times for the cell body. Numerical analysis reveals 4 spermatogonial divisions and a considerable loss of spermatogenic cells during the second meiotic division and subsequent spermiogenesis. Sertoli cells constitute between 31.4% (stage 4) and 38.3% (stage 1) of the tubular epithelium. The calculated cell volume of an individual Sertoli cell increases during every cycle from 6515.3 μm³ instage 3 to 8350.0 μm³ in stage 8; that is a volume change of 22%. The Sertoli cell organelle with most prominent cyclical variations is the endoplasmic reticulum. A lipid cycle is absent in the seminiferous epithelium of the fallow deer. Inhalt: Quantitative Studien am Keimepithel des männlichen Damwilds (Dama dama). Das Keimepithel im Hoden von fünf 16 bis 17 Monate alten Damwildjährlingen (Dama dama) wurde mit morphometrischen Methoden untersucht. Tubuli seminiferi machen 77,2% des Hodenparenchyms aus; die Gesamttubuluslange pro Hoden betragt zwischen 400 und 750 m. Sechs Spermatogenesestadien können beim Damhirsch identifiziert werden, wobei für diese Einteilung wechselnde Zellassoziationen im Keimepithel zugrunde gelegt wurden. Der Durchmesser der Tubuli seminiferi wechselt zwischen 215 μm (Phase 1)und 230 μm (Phase 8). Die Tubulusepithelhöhe schwankt ebergfalls zwischen 67,6 μm in Phase 3 und 71,9 μm in Phase 8 (Spermiation). Präleptotäne habendie kleinsten Kern- und Zellvolumina (203,7 μm³ bzw. 469,1 μm³) von allen Spermatozyten I. Ordnung, Diplotäne aus Phase 4 die größten Werte (846,7 μm³ bzw. 3440,5 μm³), das ist ein Zuwachs um das Vierfache bei mKern und um das Siebenfache beim Zeilleib. Eine numerische Anaiyse derZellzahlen in Tubulusquerschnitten aus den verschiedenen Phasen der Spermatogenese erlaubt die Schlußfolgerung, daß es 4 Spermatogonienteilungen bei dieser Spezies gibt, und daß eine beträchtliche Anzahl aller rechnerisch möglichen Keimzellen während der Spermatokenese verloren geht, vor allem während der zweiten Reifeteilung und der Spermiogenese. Sertolizellen machen zwischen 31,4 (Phase 4) und 38,3% (Phase 1) des Keimepithels aus. Eine Sertolizelle aus Phase 3 besitzt ein rechnerisches Zellvolumen von 6515,3 μm³, eine Zelle aus Phase 8 ein Zellvolumen von 8350,0 μm³. Somit verringert und vergrößert sich das Volumen der einzelnen Sertolizelle um ca. 22% in jedem Keimepithelzyklus. Das endoplasmatische Retikulum der Sertolizelle ist das Organell mit den auffälligsten zyklischen Veränderungen. Der Lipidgehalt des Keimepithels ist minimal; ein Lipidzyklus im Keimepithel, wie für andere Spezies beschrieben, existiert beim Damwild nicht.     

An Ecophysiological Study of the Meiofauna of the Swartkops Estuary

Environmental correlations with mean, as well as seasonal, distribution and abundance of the meiofauna in two exposed beaches in the Swartkops Estuary, near Port Elizabeth, were elucidated. Population densities showed a direct relationship with particle size. Consequent on this, oxygen appeared to be the controlling factor although desiccation played a role in the intertidal distribution of meiofauna in sandy areas. Seasonal fluctuations in numbers were characterized by peaks occurring in spring and autumn. Variations of temperature and oxygen were found to be responsible for this pattern. The presence of the sand prawn Callianassa kraussi affected both vertical penetration and seasonal fluctuation of the meiofauna. Since fluctuation in nitrogen and chlorophyll a content of the substrate bore little relationship to the fluctuation of the meiofauna, it is concluded that food is not limiting in these areas. Biomass determinations revealed that nematodes, which were the dominant taxon, weighed 0,42 μg individual mean ash-free dry mass and harpacticoid copepods 0,47 μg. On this basis the standing crop biomass was 0,40 μm² in the sandy areas and 0,07 g/m² in the muddier areas, both to a depth of 20 cm.     

Characteristics of Gas Generation (NH3, CH4, N2O, CO2, H2O) From Horse Manure Added to Different Bedding Materials Used in Deep Litter Bedding Systems

The aim of this study was to analyze the influence of horse manure added to different bedding materials on the generation of gases (ammonia (NH₃), nitrous oxide, carbon dioxide, methane, water vapor) from deep litter bedding under standardized laboratory conditions. Two different types of straw (wheat and rye) and wood shavings were analyzed. The deep litter (substrate) was made of 25 kg of the respective bedding material, 60 kg horse feces, and 60 L ammonium chloride solution (urea), and spread out in identical chambers over 19 days (n = 3). On days 1, 8, 15, and 19, total nitrogen, total carbon, and dry matter content of the substrate, as well as the pH in 500-g samples, were measured along with. At the end of each test period, the nitrite nitrogen, nitrate nitrogen, and ammonium nitrogen contents of the leachate were analyzed. The wheat straw substrate emitted the highest concentration of NH₃ (4.31 mg/m³; P < .0001) and the wood shavings substrate emitted the lowest (1.73 mg/m³; P < .0001); the rye straw substrate generated 3.05 mg/m³. In addition, significant differences occurred during days 1 to 3 with respect to the generation of the gases NH₃, methane, nitrous oxide, carbon dioxide, and water vapor, and after the opening of the chamber on day 15. The nitrogen losses through the leachate occurred mainly in the form of nitrate, where the leachate from the wheat straw substrate had a significantly higher amount of nitrate nitrogen (44.56 mg) as compared with the leachates of the rye straw (14.49 mg; P ≤ .0001) and the wood shaving substrates (22.62 mg; P = .0010).     

Anesthesia and anesthetic action mechanism of essential oils of Aloysia triphylla and Cymbopogon flexuosus in silver catfish (Rhamdia quelen)

Objectives

To document the time for anesthesia induction and recovery using different concentrations of essential oils (EOs) of Cymbopogon flexuosus and Aloysia triphylla in silver catfish (Rhamdia quelen), and to determine whether the mechanism of action of either EO involves the benzodiazepine (BDZ) site of the GABA_A receptor.

Detomidine and the combination of detomidine and MK‐467, a peripheral alpha‐2 adrenoceptor antagonist,as premedication in horses anaesthetized with isoflurane

ObjectiveTo investigate MK-467 as part of premedication in horses anaesthetized with isoflurane.Study designExperimental, crossover study with a 14 day wash-out period.AnimalsSeven healthy horses.MethodsThe horses received either detomidine (20 μg kg⁻¹ IV) and butorphanol (20 μg kg⁻¹ IV) alone (DET) or with MK-467 (200 μg kg⁻¹ IV; DET + MK) as premedication. Anaesthesia was induced with ketamine (2.2 mg kg⁻¹) and midazolam (0.06 mg kg⁻¹) IV and maintained with isoflurane. Heart rate (HR), mean arterial pressure (MAP), end-tidal isoflurane concentration, end-tidal carbon dioxide tension, central venous pressure, fraction of inspired oxygen (FiO₂) and cardiac output were recorded. Blood samples were taken for blood gas analysis and to determine plasma drug concentrations. The cardiac index (CI), systemic vascular resistance (SVR), ratio of arterial oxygen tension to inspired oxygen (P_aO₂/FiO₂) and tissue oxygen delivery (DO₂) were calculated. Repeated measures anova was applied for HR, CI, MAP, SVR, lactate and blood gas variables. The Student's t-test was used for pairwise comparisons of drug concentrations, induction times and the amount of dobutamine administered. Significance was set at p < 0.05.ResultsThe induction time was shorter, reduction in MAP was detected, more dobutamine was given and HR and CI were higher after DET+MK, while SVR was higher with DET. Arterial oxygen tension and P_aO₂/FiO₂ (40 minutes after induction), DO₂ and venous partial pressure of oxygen (40 and 60 minutes after induction) were higher with DET+MK. Plasma detomidine concentrations were reduced in the group receiving MK-467. After DET+MK, the area under the plasma concentration time curve of butorphanol was smaller.Conclusions and clinical relevanceMK-467 enhances cardiac function and tissue oxygen delivery in horses sedated with detomidine before isoflurane anaesthesia. This finding could improve patient safety in the perioperative period. The dosage of MK-467 needs to be investigated to minimise the effect of MK-467 on MAP.     

The effect of fentanyl on the end‐tidal sevoflurane concentration needed to prevent motor movement in dogs

ObjectiveThe objectives of this study were to determine the effects of fentanyl on the end-tidal concentration of sevoflurane needed to prevent motor movement (MAC_NM) in response to noxious stimulation, and to evaluate if acute tolerance develops.Study designRandomized cross-over experimental study.AnimalsSix healthy, adult (2–3 years old), intact male, mixed-breed dogs weighing 16.2 ± 1.1 kg.MethodsSix dogs were randomly assigned to receive one of three separate treatments over a 3 week period. After baseline sevoflurane MAC_NM (MAC_NM-B) determination, fentanyl treatments (T) were administered as a loading dose (Ld) and constant rate infusion (CRI) as follows: T1-Ld of 7.5 μg kg^?1 and CRI at 3 μg kg^?1 hour^?1; T2-Ld of 15 μg kg^?1 and CRI at 6.0 μg kg ^?1 hour^?1; T3-Ld of 30 μg kg^?1 and CRI at 12 μg kg^?1 hour^?1. The MAC_NM was defined as the minimum end-tidal sevoflurane concentration preventing motor movement. The first post-treatment MAC_NM (MAC_NM-I) determination was initiated 90 minutes after the start of the CRI, and a second MAC_NM (MAC_NM-II) determination was initiated 3 hours after MAC_NM-I was established.ResultsThe overall least square mean MAC_NM-B for all groups was 2.66%. All treatments decreased (p < 0.05) MAC_NM, and the decrease from baseline was 22%, 35% and 41% for T1, T2 and T3, respectively. Percentage change in T1 differed (p < 0.05) from T2 and T3; however, T2 did not differ from T3. MAC_NM-I was not significantly different from MAC_NM-II within treatments.Conclusions and clinical relevanceFentanyl doses in the range of 3–12 μg kg^?1 hour^?1 significantly decreased the sevoflurane MAC_NM. Clinically significant tolerance to fentanyl did not occur under the study conditions.     

Comparison of the neuromuscular blocking effects of cisatracurium during isoflurane or propofol anesthesia in dogs

ObjectiveTo compare the neuromuscular blocking effects of cisatracurium during isoflurane versus propofol anesthesia in dogs.Study designProspective, randomized study.AnimalsA total of 20 healthy, client-owned dogs (16 females, four males) weighing 12.5–22 kg and aged 1–8 years.MethodsDogs undergoing elective surgery were randomized in equal numbers to an isoflurane (ISO) or propofol (PPF) group. Other drugs used during anesthesia were equal between groups. Single-twitch (ST) stimulation was used to monitor neuromuscular response. After recording the baseline ST (T0), cumulative doses of cisatracurium (0.05 mg kg^–1) were administered intravenously until ST/T0 ≤5%. Effective doses 50 (ED₅₀) and 95 (ED₉₅) of cisatracurium in each group were calculated from group dose-response curves. Recovery of ST (TR) was defined as spontaneous recovery of ST to 80–120% of T0 remaining stable for 2 minutes. The ST after each dose of cisatracurium, duration 25% (time after the last dose until 25% recovery of TR), recovery index (time to recovery from 25% to 75% of TR) and duration to TR (time after the last dose until recovery of TR) were recorded.ResultsIncremental doses of cisatracurium, median (range), were 2 (1–3) in ISO and 4 (2–5) in PPF to achieve ≥95% depression of ST/T0 (p < 0.01). ED₅₀ and ED₉₅ were 20 μg kg^–1 and 117 μg kg^–1 in ISO and 128 μg kg^–1 and 167 μg kg^–1 in PPF, respectively. The duration 25%, recovery index and duration to TR, median (range), were longer in ISO [22.6 (10.3–24.3), 5.3 (3.0–7.8) and 36.1 (20.1–49.7) minutes, respectively] than in PPF [10.2 (6.8–16.5), 3.0 (2.0–3.8) and 17.7 (14.2–28.7) minutes, respectively] (p < 0.01).Conclusions and clinical relevanceCisatracurium-induced neuromuscular blockade was significantly enhanced and prolonged by isoflurane compared with propofol.     

Evaluation of a romifidine constant rate infusion protocol with or without butorphanol for dentistry and ophthalmologic procedures in standing horses

ObjectiveTo compare the clinical usefulness of constant rate infusion (CRI) protocols of romifidine with or without butorphanol for sedation of horses.Study designProspective ‘blinded’ controlled trial using block randomization.AnimalsForty healthy Freiberger stallions.MethodsThe horses received either intravenous (IV) romifidine (loading dose: 80 μg kg^?1; infusion: 30 μg kg^?1 hour^?1) (treatment R, n = 20) or romifidine combined with butorphanol (romifidine loading: 80 μg kg^?1; infusion: 29 μg kg^?1 hour^?1, and butorphanol loading: 18 μg kg^?1; infusion: 25 μg kg^?1 hour^?1) (treatment RB, n = 20). Twenty-one horses underwent dentistry and ophthalmic procedures, while 19 horses underwent only ophthalmologic procedure and buccal examination. During the procedure, physiologic parameters and occurrence of head/muzzle shaking or twitching and forward movement were recorded. Whenever sedation was insufficient, additional romifidine (20 μg kg^?1) was administered IV. Recovery time was evaluated by assessing head height above ground. At the end of the procedure, overall quality of sedation for the procedure was scored by the dentist and anaesthetist using a visual analogue scale. Statistical analyses used two-way anova or linear mixed models as relevant.ResultsSedation quality scores as assessed by the anaesthetist were R: median 7.55, range: 4.9–9.0 cm, RB: 8.8, 4.7–10.0 cm, and by the dentist R: 6.6, 3.0–8.2 cm, RB: 7.9, 6.6–8.8 cm. Horses receiving RB showed clinically more effective sedation as demonstrated by fewer poor scores and a tendency to reduced additional drug requirements. More horses showed forward movement and head shaking in treatment RB than treatment R. Three horses (two RB, one R) had symptoms of colic following sedation.Conclusions and clinical relevanceThe described protocols provide effective sedation under clinical conditions but for dentistry procedures, the addition of butorphanol is advantageous.     

播种方式对燕麦和饲用豌豆饲草产量及品质的影响

为研究青海省适宜的禾豆混播方式，本研究以行距为30 cm,25 cm,20 cm和15 cm混播、间作、单播燕麦(Avena sativa)和饲用豌豆(Pisum sativum)两种饲草，分析研究不同混播方式下饲草产量及营养品质，以期为青藏高原高寒地区燕麦与饲用豌豆混播草地的建植提供参考。结果表明：间混作对饲草相对生长速率及饲草总产量均具有显著影响，其中混播处理的草产量高于间作处理。不同播种行距对饲草产量具有显著影响，饲草产量从高到低依次排序为：30 cm>25 cm>15 cm>20 cm。间混作对饲草营养成分具有显著影响，其中混播处理的粗蛋白含量高于间作处理，中性洗涤纤维含量低于间作处理，说明同行混播更有利于提高饲草品质；行距为30 cm与25 cm时，其各营养指标相对优于其他两个行距。通过合理的群体空间结构配置可以提高草产量，其中混播间距30 cm处理综合表现最优，其次为间作行距30 cm播种。     

Effects of different doses of dexmedetomidine on anaesthetic induction with alfaxalone – a clinical trial

ObjectiveTo document the effects of two doses of dexmedetomidine on the induction characteristics and dose requirements of alfaxalone.Study designRandomized controlled clinical trial.AnimalsSixty one client owned dogs, status ASA I-II.MethodsDogs were allocated randomly into three groups, receiving as pre-anaesthetic medication, no dexmedetomidine (D₀), 1 μg kg^?1 dexmedetomidine (D₁) intramuscularly (IM) or 3 μg kg^?1 dexmedetomidine IM (D₃). All dogs also received 0.2 mg kg^?1 methadone IM. Level of sedation was assessed prior to induction of anaesthesia. Induction of general anaesthesia was performed with alfaxalone administered intravenously to effect at a rate of 1 mg kg^?1 minute^?1; the required dose to achieve tracheal intubation was recorded. Anaesthesia was maintained with isoflurane in oxygen. Cardiopulmonary parameters were recorded throughout the anaesthetic period. Quality of intubation, induction and recovery of anaesthesia were recorded. Quantitative data were compared with one-way anova or Kruskal-Wallis test. Repeated measures were log-transformed and analysed with repeated measures anova (p < 0.05).ResultsTreatment groups were similar for categorical data, with exception of sedation level (p < 0.001). The doses (mean ± SD) of alfaxalone required for intubation were D₀ 1.68 ± 0.24, D₁ 1.60 ± 0.36 and D₃ 1.41 ± 0.43, the difference between D₀ and D₃ being statistically significant (p = 0.036). Heart and respiratory rates during the anaesthetic period were significantly different over time and between groups (p < 0.001); systolic arterial blood pressure was significantly different over time (p < 0.001) but not between groups (p = 0.833). Induction quality and recovery scores were similar between groups (p = 1.000 and p = 0.414, respectively).Conclusions and clinical relevanceThe administration of alfaxalone resulted in a good quality anaesthetic induction which was not affected by the dose of dexmedetomidine. Dexmedetomidine at 3 μg kg^?1 IM combined with methadone provides good sedation and enables a reduction of alfaxalone requirements.     

Short-wave solar radiation level willingly tolerated by lactating Holstein cows in an equatorial semi-arid environment

The amount of short-wave solar radiation willingly tolerated by lactating Holstein cows on pasture was determined in an equatorial semi-arid environment. The study was carried out on a dairy farm located in Limoeiro do Norte, CE, northeastern Brazil. The observed behaviours were as follows: grazing, under the sun, under the shade, standing, lying, ruminating, idling and wallowing in the water. The behaviours were recorded using instantaneous scan sampling at regular intervals of 15 min from 0600 to 1800 hours over 5 days. On all sampling days, the meteorological variables, including local short-wave solar radiation (R _S-W, W m^?2), were recorded. The R _S-W data were divided into five levels. The sun exposure was more frequent under low (100 %) and moderately low (97 %) levels, when R _S-W remained below 500 W m^?2. The grazing was more intense under low (100 %) and moderately low (93 %) levels. Above 500 W m^?2, the grazing time significantly decreased (11 %). The cows avoided grazing under high (0 %) and very high (0 %) levels, when R _S-W exceeded 700 W m^?2. The ruminating behaviour was more frequent under high (33 %) and very high (37 %) levels, in which the highest averages of R _S-W were recorded (815 and 958 W m^?2, respectively). The standing posture was more frequent under low (100 %) and moderately low (97 %) levels. Therefore, the critical R _S-W level that motivates cows to stop grazing and seek shade was in the interval between 500 and 700 W m^?2.     

Effect of lactic acid bacteria,molasses, and their combination on the fermentation quality and bacterial community of cassava foliage silage

This study investigated the effects of LAB inoculants (L) and molasses (M) on the microbial community and fermentation quality of cassava foliage (CF). The small segments (about 2–3 cm) CF were ensiled in plastic bags and incubated at normal temperature (25°C). Four treatments were carried out as follows: control (no additives, CK), LAB inoculants (Lactobacillus plantarum, L), molasses (M), and LAB in combination with molasses (LM). The LAB and molasses obviously altered the bacterial community structure of the CF silage and enhanced the fermentation quality. The combination addition could increase the abundance of Lactobacillus and reduce the Pseudomonas. The LAB and molasses also significantly elevated the lactic acid concentration (P < 0.001) and decreased the pH (P < 0.001), as well as the concentrations of acetic acid, propionic acid, butyric acid, and ammonia-N (P < 0.05). In addition, the combination treatment displayed more effective results on silage fermentation. The LAB and molasses improved the fermentation quality of the CF silage by altering the bacterial community structure. Furthermore, the bacterial community was significantly correlated with fermentation indexes.