Stability and partitioning of closantel and rafoxanide in ruminal fluid of sheep

The stability and the partitioning of closantel and rafoxanide in ruminal fluid (RF) was examined in vitro. Stability was evaluated in two studies in a ruminal fluid-artificial saliva (RF-AS) mixture containing either drug. Drug concentrations were measured in samples collected sequentially from four batches of RF-AS fortified with either closantel or rafoxanide in one study and in four separately incubated aliquots of a RF-AS mixture of each drug in the second study at the start and at various intervals during a 24 h incubation period. The viability of the in vitro RF-AS incubation model was validated by the presence of digoxin degradation (T1/2 of 39,1 +/- 13 h) and by the absence of significant time related differences (P> 0,5) in volume of gas produced, pH and methylene blue reduction time of the RF-AS drug mixture. Partitioning of closantel and rafoxanide was determined by measuring the relative drug concentration of the fluid and particulate phases in RF fortified with either drug at different concentrations. Closantel and rafoxanide were shown to be stable in a RF-AS mixture and were not subjected to any significant biodegradation. An initial marked reduction in drug concentration measured in the RF-AS mixture during the first 2 h of incubation was attributed to the attachment of both drugs onto particulate matter. This was subsequently confirmed in the partitioning study. More than 80% of closantel and rafoxanide was shown to be associated with the particulate phase of RF     

沙地恢复草场放牧绵羊体增重及瘤胃发酵参数动态变化

本研究选择浑善达克沙地腹地内蒙古自治区正蓝旗正在围封恢复中的沙地草场,进行毛肉兼用细毛羊暖季自由放牧和划区轮牧试验,结合放牧绵羊增重及瘤胃发酵参数动态变化指标评价恢复阶段沙地草场牧养能力。结果表明,暖季(6-10月)放牧绵羊增重明显,3个放牧区绵羊平均月增重分别为2.46,5.08,5.52和2.29kg,而不同放牧方式对绵羊增重效果没有显著影响;在7-8月放牧绵羊瘤胃发酵水平较好,空腹到采食后7h内发酵参数动态变化表现为:瘤胃pH7.01-6.38-6.47-6.77、NH₃-N浓度6.02-9.26-10.75-10.82mg/100mL、总VFA浓度31.37-42.99-58.55-65.28mmol/L。因此在围封恢复5~6年的沙地退化草场上进行绵羊的暖季适度放牧,可以产生较好的增重及瘤胃发酵效果。     

放牧季节和绵羊年龄对松嫩草地放牧绵羊血液指标的影响

草地饲草季节动态变化是影响放牧家畜营养的主要因素,而如何通过放牧家畜自身的变化揭示草地质量变化的影响及程度还需要系统的探讨。本研究分别选择3月龄羔羊、3岁和6岁成年母羊各8只,分别在春季、夏季、秋季和冬季采集血样进行分析测定,对松嫩草地放牧绵羊血液常规指标和矿物质指标进行了动态监测,明晰不同季节、不同年龄对这些指标的影响及变化规律,旨在筛选评估家畜营养状态的敏感指标,为放牧家畜营养管理提供理论依据。结果表明,放牧季节和绵羊年龄以及季节和年龄互作均对放牧绵羊血中总蛋白、白蛋白、尿素氮、甘油三酯和葡萄糖含量有显著影响(P0.05)。血液常量矿物质结果标明,年龄对血液中钠没有显著影响,季节有显著影响(P0.05),但二者互作对血液中的钠无显著影响(P0.05);年龄和季节对血液中钾和氯有显著影响(P0.05),而且年龄和季节的互作对血液中氯含量有显著影响(P0.05);年龄和季节对血液中钙有显著影响(P0.05),但二者互作对其无显著影响(P0.05);年龄和季节对血液中磷含量有显著影响(P0.05),二者互作对其也影响显著(P0.05);年龄对血液中镁没有显著影响(P0.05),季节有显著影响(P0.05)。总之,从变化幅度来看,血液中尿素氮和磷是绵羊血液中随季节变化较为敏感的指标。     

An assessment of the effects of ruminal selenium pellets given to young sheep grazing selenium-deficient pastures

Thirty-eight species of small cetaceans termed “dolphins” and “porpoises” are listed. This review is a contribution to the growing community and veterinary interest in the welfare and diseases of these animals.     

Serum and ruminal fluid characteristics of beef cows grazing oat pastures and supplemented with or without lasalocid

Thirty-two mature, pregnant beef cows (avg age 8 yr, body wt 550 kg) grazing oat pastures were used to determine the effects of lasalocid on serum mineral and ruminal fluid volatile fatty acid (VFA) concentrations. Cows were blocked by breed type and assigned randomly to eight, 2-ha pastures containing oat forage from December 17, 1985 to May 6, 1986. The cows were fed .25 kg of ground corn with or without 200 mg of lasalocid daily. Based upon analyses of forage mineral composition (.53, .25, .14, .3 and 2.5% of dry matter for Ca, P, Mg, Na and K, respectively), all macrominerals except Mg were in sufficient quantities to meet the requirement for lactating cows. Lasalocid supplementation did not affect serum Mg, K or Zn concentrations (P greater than .05). During the April sampling, serum Ca was higher (P less than .05) and serum Na was lower (P less than .05) in cows supplemented with lasalocid compared with controls. The molar proportion of acetate was decreased (P less than .05) in ruminal fluid of cows fed lasalocid by d 56 (February 11); the molar proportions of acetate and butyrate were decreased (P less than .05), which decreased (P less than .05) the acetate: propionate ratio by d 84 (March 11) of supplementation. This study suggests that lasalocid is effective in altering ruminal VFA and serum mineral concentrations in cows grazing small grain forages.     

藏系绵羊瘤胃细菌数量及其放牧地牧草养分随季节变化的研究

试验分别于春、夏、秋和冬季,随机选择3只同群常年放牧健康的藏系绵羯羊(2岁),屠宰后采集瘤胃内容物。采用瘤胃细菌通用引物和实时定量PCR技术,研究瘤胃细菌数量随季节的动态变化。结果表明,1)夏季瘤胃细菌数量显著(P＜0.05)高于其他3个季节,分别是春季、秋季、冬季细菌数量的5.56,2.35和2.49倍;秋、冬季是春季细菌数量的2.38和2.23倍;而秋和冬季瘤胃细菌的数量差异不显著(P＞0.05)。2)夏季藏系绵羊采食量分别为春季、冬季和秋季的1.98,1.61和1.80倍,饲料中的纤维性物质含量增高,采食量也随着降低,瘤胃细菌的数量也相应降低;3)实时定量PCR技术能准确的反映出放牧藏系绵羊瘤胃细菌数量随季节的动态变化。     

绵羊瘤胃酸中毒的诊疗

绵羊主要由于过食玉米、小麦等谷物饲料,于瘤胃内高度发酵,产生大量乳酸而致代谢性酸中毒.报告如下.     

Acute ruminal indigestion,alkalosis and death of cattle grazing kikuyu

Abstract

Extract

The increased vascular permeability that follows the intrapleural injection of turpentine in the sheep is due to the local re-ease of histamine and is continued by the activation of other mechanisms (Lancaster and Vegad, 1967 Lancaster, M. C. and Vegad, J. L. 1967. Suppression of the early inflammatory response in the sheep by strophanthin G. Nature, Lond., 213: 840–841.  [Google Scholar]). In further studies of the inflammatory response, an attempt was made to deplete the skin locally of its histamine content. It was found that the intra-dermal injection of a total of 80 mg/kg of compound 48/80, a histamine liberator, into a 20 kg lamb, caused acute respiratory distress and death. Death was presumed to be due to the release of lethal amounts of histamine by this compound. To investigate the sensitivity of the sheep to histamine, the toxicity of compound 48/80 and of histamine was tested.     

Effects of sheep and cattle alternate grazing on sheep parasitism and production

Production of sheep (nursing ewes) grazing alternately with cattle (growing weaned heifers) was compared to the production of sheep or cattle grazing alone (controls). Pasture production and sheep parasitism were also monitored. The herbage allowance was higher for the control heifers than for the alternate heifers, but the leaf to green material ratio (LGMR) was lower, and no difference on heifer growth was revealed (443 vs. 431g.d^-1, P = 0.54). The LGMR was higher for the alternate sheep (+3 points) than for the control sheep, except during the dry season, when the herbage density was lower. The effects of parasitism on the packed cell volume of alternate ewes and lambs were lower than those of control ewes and lambs. However, the infection of sheep by Cooperia sp. (better adapted to cattle) was significantly higher for the alternate sheep than for the controls, and some indication of cattle infection by Haemonchus contortus was suggested. The 70-day lamb weight was higher in the alternate grazing system than in the control (+0.76,+1.11 and+0.61kg for the dry, intermediate and rainy seasons, respectively), and the average 70-day lamb production per ewe exposed was 21.42kg in the alternate grazing system vs. 18.59kg in the control (P = 0.003).     

Effects of salinomycin on ruminal characteristics and performance of grazing beef steers

Grazing trials were conducted for 2 yr using weanling Brahman crossbred beef steers to evaluate graded levels of salinomycin (0, 50, 100 or 150 mg. head-1.d-1) for 161 d and to evaluate salinomycin in a free-choice mineral supplement (99 d). The 40 and 48 steers in trials 1 and 2 had average initial weights of 198 and 285 kg, respectively. In trial 1, steers were group-fed to consume either 0, 50, 100 or 150 mg of salinomycin.head-1.d-1 in .9 kg ground corn while grazing bermudagrass pastures. Both linear (P less than .01) and quadratic (P less than .05) effects were observed for steer performance as salinomycin level increased from 0 to 150 mg.head-1.d-1. Linear increases (P less than .01) in ruminal NH3-N (mg/100 ml) and in the molar proportion of propionate and decreases (P less than .01) in butyrate and acetate/propionate were detected. In trial 2, mineral supplements with and without salinomycin were fed free-choice to steers on bermudagrass pasture. The mean salinomycin intake of 38 mg.head-1.d-1 was lower than anticipated as a result of the instability of salinomycin in the mineral supplement and the slightly lower intake (65 g/d) than anticipated (75 g/d). Performance of steers was not influenced by salinomycin supplementation in trial 2. The ionophore salinomycin at intakes over 50 mg.head-1.d-1 appears to increase the performance of steers grazing bermudagrass pasture.     

Effects of 9,10 anthraquinone on ruminal fermentation,total-tract digestion,and blood metabolite concentrations in sheep

The objective of this study was to evaluate the effects of adding 9,10 anthraquinone, a known inhibitor of methanogenesis and sulfate reduction, on blood metabolites, digestibility, and distribution of gas in sheep. In all experiments, we fed a complete pelleted diet that contained 17.5% crude protein and 24.5% acid detergent fiber. In an 8-wk study, feeding up to 66 ppm (dry matter basis) of 9,10 anthraquinone had no adverse effects on blood metabolites including indicators of normal enzyme function, mineral concentrations, and hematological measurements. Feeding 9,10 anthraquinone had no effect on average daily gain, although sheep fed a diet containing 66 ppm of 9,10 anthraquinone numerically gained the least weight. The ruminal molar proportions of acetic acid were decreased (P < 0.05) and the molar proportions of propionic acid were increased (P < 0.05) in sheep fed 1.5 and 66 ppm 9,10 anthraquinone when compared to those fed an unsupplemented diet. In a digestion trial, 9,10 anthraquinone (33 and 66 ppm) had no effect on the apparent digestion of nutrients in the total gastrointestinal tract. In a metabolism study, ruminal gasses were collected by rumenocentesis and analyzed for methane and hydrogen concentrations. Feeding 500 ppm of 9,10 anthraquinone to sheep resulted in a decrease (P < 0.07) in the concentration of methane, but an increase (P < 0.05) in hydrogen concentration of ruminal gas throughout the 19 d of feeding. There was no indication of ruminal adaptation throughout this time. These results are the first to show that 9,10 anthraquinone can partially inhibit in vivo rumen methanogenesis, which supports previous in vitro findings. In addition, at the concentrations used in this study, 9,10 anthraquinone was not toxic to ruminants.     

The effects of delays between restraint and sampling on some blood parameters in sheep

Twenty three non pregnant, non lactating aged Merino and Border Leicester ewes were subject to four jugular venipunctures one hour apart (times 0, 1, 2 and 3). Four different delay intervals of 12.5, 64.0, 128.0 and 252.9 seconds between catching and sampling (delays 1, 2, 3 and 4) were used on each sheep in a random manner. Estimates were made of packed cell volumes (PCVs), plasma and erythrocyte sodium and potassium concentrations. The mean PCV at time 0 of 35.4 per cent was significantly higher than the levels of 33.1, 31.8 and 32.2 per cent at times 1, 2 and 3 respectively. There was no significant difference between the means at times 1, 2 and 3. The mean plasma potassium concentrations at time 0 of 4.37 mmol/l was significantly higher than the levels of 4.16 and 4.14 mmol/l at times 1 and 3 respectively. Delays had no significant effects on the means of any of the parameters studied. The findings strongly suggest that sheep become excited by initial handling but not by subsequent venipunctures and that a delay between catching and sampling of between 12.5 and 252.9 second has no effect on the blood constituents studied.     

The effects of delays between restraint and sampling on some blood parameters in sheep

Twenty three non pregnant, non lactating aged Merino and Border Leicester ewes were subject to four jugular venipunctures one hour apart (times 0, 1, 2 and 3). Four different delay intervals of 12.5, 64.0, 128.0 and 252.9 seconds between catching and sampling (delays 1, 2, 3 and 4) were used on each sheep in a random manner. Estimates were made of packed cell volumes (PCVs), plasma and erythrocyte sodium and potassium concentrations. The mean PCV at time 0 of 35.4 per cent was significantly higher than the levels of 33.1, 31.8 and 32.2 per cent at times 1, 2 and 3 respectively. There was no significant difference between the means at times 1, 2 and 3. The mean plasma potassium concentrations at time 0 of 4.37 mmol/l was significantly higher than the levels of 4.16 and 4.14 mmol/l at times 1 and 3 respectively. Delays had no significant effects on the means of any of the parameters studied. The findings strongly suggest that sheep become excited by initial handling but not by subsequent venipunctures and that a delay between catching and sampling of between 12.5 and 252.9 second has no effect on the blood constituents studied.