饲粮中添加牛至精油和莫能菌素对荷斯坦犊牛血清生化指标、消化酶活性及瘤胃微生物区系的影响

旨在研究牛至精油（oregano essential oil,OEO）与莫能菌素（monensin,MON）对荷斯坦犊牛血清生化指标、消化酶活性以及瘤胃微生物区系的影响。本试验前期阶段选用了体重相近（（41.31±2.23）kg）,体况良好的荷斯坦初生犊牛80头,随机分为4组,每组20头,采用单栏饲养。对照组饲喂全脂牛乳和颗粒饲料,其他3个试验组在饲喂全脂牛乳和颗粒饲料的基础上分别添加4 g·kg^-1牛至精油、3.6 g·kg^-1莫能菌素和7.6 g·kg^-1牛至精油和莫能菌素的混合物,饲喂至56、70日龄时,从每组中选取6头体重相近的公犊,颈静脉采血测定血清指标,并通过口腔导管的形式采集犊牛的瘤胃液,检测消化酶活性以及瘤胃微生物区系。结果表明：1）添加牛至精油显著提高了56日龄犊牛血清中TP、SOD、GSH和GSH-Px的浓度（P ≤ 0.05）;莫能菌素对56、70日龄犊牛BUN浓度有降低的趋势（P<0.10）。2）牛至精油显著降低了56、70日龄犊牛瘤胃中产琥珀酸丝状杆菌的数量（P<0.05）,显著提高了白色瘤胃球菌的数量（P ≤ 0.05）;莫能菌素显著降低了56、70日龄犊牛瘤胃中原虫的数量（P ≤ 0.05）,并有降低白色瘤胃球菌数量的趋势（P<0.10）,在56日龄时,莫能菌素有降低犊牛瘤胃中黄色瘤胃球菌数量的趋势（P<0.10）;牛至精油和莫能菌素对56、70日龄犊牛瘤胃中溶纤维丁酸弧菌有显著的交互作用（P ≤ 0.05）;在56日龄时,牛至精油和莫能菌素对栖瘤胃普雷沃氏菌有交互作用的趋势（P<0.10）,而在70日龄时则呈显著的交互作用（P ≤ 0.05）。3）牛至精油和莫能菌素对56、70日龄犊牛瘤胃中胃蛋白酶浓度有显著的交互作用（P ≤ 0.05）。综上所述,饲粮中添加牛至精油可提高犊牛的免疫力和抗氧化能力。莫能菌素在抑制瘤胃内原虫数量上强于牛至精油,牛至精油对提高主要蛋白质降解菌数量的作用效果优于莫能菌素。总之,牛至精油可改善犊牛的健康状况以及调控瘤胃微生物区系,牛至精油作为天然植物抗生素可替代犊牛期预防性治疗的其他类抗生素生长促进剂。     

兽医微生物学设计性实验教学探索

兽医微生物学实验教学中,增设了2个设计性试验,学生根据试验要求查阅资料、制定试验方案、独立进行试验操作、结果判断与分析,使学生牢固掌握了病原微生物的诊断程序,提高了学生分析问题、解决问题的能力,是兽医微生物学试验教学改革的有益尝试。     

黄牛食前食后瘤胃纤毛虫及瘤胃液pH值的调查

在饲料种类、饲喂方法、日粮总量等不变情况下,对31头黄牛食前食后的瘤胃液 PH 值及纤毛虫数作了调查。结果:食后(上午)瘤胃液 pH 值较食前(下午)低0.2;纤毛虫少,7.42万/ml.一天内瘤液 pH 值平均为6.8,纤毛虫平均为23.6万/Ml     

Chemical Composition and Ruminal Dry Matter and Crude Protein Degradability of Spineless Cactus

The objective of this study was to determine ruminal degradability of the dry matter (DM) and crude protein (CP) of 10 varieties of spineless cactus (Opuntia spp.) grown in north‐eastern Brazil. Two ruminally fistulated steers were used in a randomized complete block design. Ash, CP, acid detergent fiber, and acid detergent lignin levels ranged from 10.4 to 13.3 %, 6.2–7.7 %, 19.8–24.8 % and 3.4–5.4 %, respectively. Relative to the other cactus varieties, Redonda had the highest (P < 0.05) in situ soluble DM fraction and effective DM degradability. No differences in effective DM degradability were observed between the other cactus varieties. In situ soluble CP fraction ranged from 1.7 % of CP for the 69 IPA/UFRPE variety to 11.1 % of CP for the Gigante variety. Slowly degradable CP fraction and its rate of degradation were similar among the cactus varieties (average 90 % of CP and 9 % h^?1, respectively). The cactus variety 69 IP/UFRPE had a lower (P < 0.05) effective ruminal CP degradability (ECPD) than the other varieties, which had a similar ECPD (average 66 % of CP). It was concluded that differences in ruminal degradability exist between cactus varieties, with more variations observed for ruminal DM than for CP degradability.     

Severe soft tissue infections in dogs: 47 cases (1996–2006)

Objective– To describe the patient population, microbiological findings, treatment and outcome in dogs with severe soft tissue infections (SSTIs) and to compare survivors to nonsurvivors. Design– Retrospective study. Animals– Forty‐seven dogs with confirmed soft tissue infections originating from the SC tissues, muscle or fascia. Interventions– None. Measurements and Main Results– Physical and clinicopathologic data on presentation, microbiological and histopathological findings, antimicrobial treatment and outcome. Dogs with SSTIs were predominantly large breed dogs with a median body weight of 35.6 kg. Incidence of pre‐existing conditions (immunomodulating diseases, blunt trauma, injections, clean surgical procedures) that could have contributed to development of SSTIs was 34%. Abnormal physical examination and diagnostic parameters on presentation included increased body temperature (median temperature 39.5 °C [103.1 °F]) and low arterial blood pressure (median systolic blood pressure 103.5 mm Hg). While Streptococcus species were the most commonly isolated bacteria, the incidence of polymicrobial infections differed between antemortem (38.7%) and postmortem (57.1%) cultures. The overall survival rate was 46.8%. Survivors had a higher body weight and higher respiratory rate on presentation than nonsurvivors. Nonsurvivors had a significantly lower WBC count and higher lactate, BUN, aspartate aminotransferase, and bilirubin concentrations. Histopathologic examination of tissue specimens showed that the degree of necrosis was higher in survivors compared with nonsurvivors. Conclusions– SSTIs in dogs are serious conditions associated with high mortality, significant inflammatory changes, and cardiovascular compromise. A number of conditions, including those that compromise skin integrity and immunomodulating diseases have been identified in our patient population and could have contributed to development of SSTIs. Polymicrobial infections occurred in many cases, necessitating broad‐spectrum antimicrobial coverage.     

Effects of forage source and particle size on chewing activity,ruminal pH,and saliva secretion in lactating Holstein cows

The present study investigated the effects of dietary forage source (quality) and particle size on chewing activity, saliva secretion, and ruminal pH. Twelve multiparous lactating Holstein cows, four of which were ruminally cannulated, were used in a replicated 4 × 4 Latin square experimental design with a 2 × 2 factorial arrangement of treatments. Cows fed wild‐rye hay diets had longer daily eating times than cows fed oaten hay diets. Treatments had no effect on ruminating time; therefore, resting time varied inversely to eating time. Neither the rate nor the amount of saliva secretion while eating, ruminating, or resting was affected by diet, resulting in similar total daily saliva secretions across treatments (231 L/day). Total volatile fatty acids (VFAs) in the ruminal fluid from animals fed oaten hay diets were higher than those from animals fed wild‐rye hay diets; further, VFAs increased with decreasing forage particle size (FPS). Consistent with elevated VFA concentrations, reducing FPS and including oaten hay in the diet decreased mean ruminal pH and increased the daily time of ruminal pH under 5.8. Results of this study suggest that forage source and particle size affect ruminal pH might be via variations in VFA production rather than increased salivary recycling of buffering substrates.     

Effects of feeding condensed barley distillers soluble on growth rate,ruminal fermentation,plasma metabolites,and myofiber properties of the longissimus thoracis muscle in Japanese Black calves

This study evaluated the effects of condensed barley distillers soluble (CBDS) on growth rate, rumen fermentation, plasma metabolite, and myofiber properties, and gene expression related to metabolism in the skeletal muscles of Japanese Black calves, compared with soybean meal and corn. Twenty‐four calves were divided into four groups: fed 5% CBDS based on the hay dry matter weight (low CBDS) and fed soybean meal and corn at the same nutrition level (control); and fed 15% CBDS based on the hay dry matter weight (high CBDS) and fed soybean meal and corn at the same nutrition level (high soy). The daily gain was larger in the low (p = 0.08) and high (p < 0.05) CBDS groups compared with the control group. In the CBDS‐fed groups, plasma β‐hydroxybutyric acid concentrations were significantly higher at 6 months of age (p < 0.05), the percentage of type I myofibers was significantly lower and their diameters were significantly larger at 9 months of age (p < 0.05), and carnitine palmitoyltransferase 1b mRNA expression was significantly lower (p < 0.05) and citrate synthase mRNA expression tended to be lower (low; p = 0.06, high; p = 0.05) compared with control group. Thus, feeding CBDS promotes growth and leads to animals with more glycolytic and less oxidative muscle metabolism.     

The effect of central sympathectomy by 6-hydroxydopamine (6-OHDA) on the response to morphine in conscious sheep

When morphine, an opioid -agonist, was administeredin vivo into the third cerebral ventricle (ICV) of conscious sheep at 20 and 40 µg/kg body weight, it caused psychomotor excitability for 2–3 h and a significant decrease in the reticuloruminal frequency for 45 min and in the mean amplitude of the primary contractions for 65 min. From 60 min after infusion, the same doses of morphine caused a significant increase in the average amplitude of the contractions for 45 min. This suggests that an inhibitory -opioid acceptor is involved in the central control of forestomach motility and general behaviour in sheep. All the effects of morphine were completely prevented by pretreatment with 18.2 µg/kg body weight 6-OHDA ICV. These results suggest that both morphine-induced inhibition of rumen motility and psychomotor excitability are due to central noradrenergic descending system activation. The exact location of the noradrenergic system remains to be determined.     

Investigation of bacterial microorganisms in the conjunctival sac of clinically normal dogs and dogs with ulcerative keratitis in Beijing, China

Objective To determine the bacterial microorganisms in the conjunctival sac of clinically normal dogs and dogs with ulcerative keratitis in Beijing, China. The effect of breed, sex and age of dogs and season on the presence or absence of bacteria in the conjunctival sac of clinically normal dogs was evaluated. Sample population This investigation included 240 healthy dogs, 27 dogs with unilateral corneal ulcer and one dog with bilateral corneal ulcer. Procedure The 480 samples from healthy dogs and the 29 samples from dogs with ulcerative keratitis were incubated in an aerobic and 5% CO₂ environment at 37 °C for 48 h. Logistic regression analysis was performed. Statistical significance was set at P < 0.01. Results Of 480 normal eyes, Staphylococcus spp. were the most frequently isolated organisms (40.29%). Neisseria spp. (11.47%) were the next most frequently isolated organisms, followed by Corynebacterium spp. (9.4%). Of 29 eyes with ulcerative keratitis, Staphylococcus spp. were also the most frequently isolated bacteria (47.06%). Streptococcus spp. (12.94%) and Pseudomonas spp. (8.24%) were the second and third, respectively. Season (P = 0.002) was a significant factor influencing presence or absence of bacterial microorganisms in the conjunctival sac of normal dogs in Beijing, China, while the effects of breed (P = 0.095), sex (P = 0.588) and age (P = 0.866) of dogs were insignificant. Conclusion Staphylococcus spp. were the most frequently isolated organisms, and S. intermedius predominated in the conjunctival sac of clinically normal dogs and dogs with ulcerative keratitis in Beijing, China. The likelihood of detecting bacteria depends on the season.     

Effects of drought‐stressed temperate forage legumes on the degradation and the rumen microbial community in vitro

According to climate change scenarios, central Europe may expect extending drought periods during summer. Lower water availability may influence the ruminal digestion of individual forage legume species differently. To test this hypothesis, Lotus corniculatus L. (var. Bull), Medicago lupulina L. (var. Ekola), Medicago falcata L. (wild seeds) and Trifolium repens L. (var. Rivendel) were each grown in parallel lots of control and drought‐stressed monocultures. Rainout shelters (installed in May 2011 on a regrowth after first cut until harvest in mid of June) withheld rainfall of 40 mm in the drought stress treatment. Samples of dried (60°C) and milled (5 mm screen) forage legumes were incubated in a simulation experiment using Rusitec to assess drought effects on parameters for microbial metabolism. Degradability of dry matter and organic matter as well as methane production decreased in incubations with drought‐stressed compared to control variants of legume species. Degradability of crude protein, neutral detergent fibre, acid detergent fibre and residual organic matter including non‐fibre carbohydrates and lipids were affected by interactions between drought stress and species. Significant interactions were also found for ammonia concentrations, molar SCFA proportions and the microbial communities. It is concluded that drought stress for growing forage legumes influences their ruminal degradation and fermentation as well as the ruminal microbial communities of Bacteria and Archaea differently in a legume species‐dependent manner.