Dietary forage concentration and particle size affect sorting,feeding behaviour,intake and growth of Chinese holstein male calves

The objective of study was to evaluate the effect of forage concentration (F:C) and forage particle length (FPL) on sorting, feeding behaviour, intake, growth and body measurements of growing calves. Twenty‐eight weaned calves of body weight 156.79 ± 33.44 (mean ± SD) were used in 2 × 2 factorial arrangements with the factors FPL of hay grass (full and short) and hay grass concentrations (low, 50% and high, 65%). The treatments were as follows: full length (FL) with low F:C (50:50), FL with high F:C(65:35), short length (SL) with low F:C (50:50) and SL with high F:C (65:35). Increasing F:C and decreasing FPL enhanced sorting for short and fine particle and sorting against long particle (p < 0.05). Dry matter intake (DMI) was decreased by decreasing the FPL (p < 0.05). Increasing F:C (65:35) increased the DMI (p < 0.05). A positive interaction between FPL and F:C was found for (daily weight gain) DWG, weight gain (WG) and feed conversation ratio (FCR) (p < 0.05). In case of feeding behaviour, interaction for eating time and eating time per kilogram DM was present. Increasing the F:C increased the eating time in both FL and SL (p < 0.05). Chopping of hay had decreased the chewing time (p < 0.05). Increasing F:C increased chewing time per kilogram DMI. High F:C decreased the lying time (p < 0.05) in FL and SL treatments (p < 0.05). Increasing F:C reduced the overall abnormal behaviour (p < 0.05). These results suggested that animals performed better at higher F:C at SL diet. Intensity of sorting for short and fine particle and against long particle increased at higher F:C and SL diets. Eating time and eating time per kilogram DMI increased by increasing F:C level in both FL and SL treatments. Chewing time increased by increasing the FPL, while increasing the F:C enhanced the chewing time per kilogram DMI and reduced animal's abnormal behaviour.     

Effects of Different Levels of Concentrate Supplement on Nutrition Digestion and Metabolism,Blood Biochemical Indexes and Body Weight Gain in 6 Months Old Yili Foals

6 months old Yili foals were used as the experimental animal fed with different levels concentrate supplement to study the effects of fed with different levels concentrate supplement on digestion and metabolism,blood biochemical indexes and body weight gain by total feces and urine collection method,provide evidence for 6 months old Yili foals feeding.According to similar weight,20 weaned 6 months old Yili foals (all males) whose average weight was (145.28±1.69)kg were randomly divided into 4 groups named groups Ⅰ,Ⅱ,Ⅲ and Ⅳ,each group of 5 weaned Yili foals(all males).All Yili foals were fed with alfalfa 4 kg/d,basised on this,groups Ⅰ,Ⅱ,Ⅲ and Ⅳ were fed with 0.4,0.6,0.8,1.0 kg/d concentrate supplement.20 d digestion and metabolism experiment,comprised 16 d adaptation and 4 d collection.The results showed that as the amount of concentrate supplement feeding increased,nutrition intake,amount of nutrient digestion of DM,OM,CP,Ca,DE,ME,retention rate of N,Ca increased.There were no significant effects on the content of TP,GLB,ALB,and BUN in plasma of 6 months old Yili foals(P > 0.05),but the content of TP,GLB in plasma showed an increased trend,the concentration of BUN in plasma showed a decreased trend.The ADG of 6 months old Yili foals was gradually increased as the amount of concentrate supplement feeding increased.Therefore,increasing amount of concentrate supplement feeding of 6 months old Yili foals could increase the nutrient intake,digestion rate and retention rate,also could strengthen the body's immune ability,improved nitrogen deposition and the average daily gain.     

15%哒·阿维热雾剂的配制及其对橡胶六点始叶螨的药效

通过选用合适的原药、助剂、工艺,配制了闪点高、粘度适中、低毒、冷热贮稳定性好且可用于喷烟、喷雾及超低量喷雾的15%哒.阿维菌素多功能热雾剂,并测定热雾剂对橡胶六点始叶螨的毒力与药效。热雾剂对雌成螨的毒力回归方程为Y=5.738 3+2.285 6x,LC50为0.475 3μg/mL,幼螨LC50为0.190 4μg/mL,卵LC50为0.921 3μg/mL。苗圃防治试验持效期达35 d以上。施药量为3 000 mL/hm2时,小区试验药后15 d防效达90.28%。经过7 a的大田防洽试验,表明15%哒.阿维热雾剂对橡胶六点始叶螨有良好的控制作用。当高峰前期每百片胶叶害螨达30头以上时,采用热雾剂2 250~3 000 mL/hm2进行预防性施药,防治效果达81.2%以上,全年施药1次可控制害螨的发生。     

肉牛日粮精料进食水平对淀粉的瘤胃发酵和小肠表观消化率的影响

为了研究日粮精料进食水平对肉牛真胃食糜淀粉流量及其表观消化率的影响,试验选择体重650kg左右荷斯坦(Holstein)公牛3头,安装有瘤胃、真胃瘘管,按3×3拉丁方试验设计分别饲喂粗料进食量相同而精料进食量不同的3种日粮,以三氧化二铬(Cr2O3)作真胃食糜标记物,全收粪法收集粪样,测定真胃食糜和粪中的淀粉流量及在瘤胃内、真胃后段消化道(简称肠道)内的表观消化率。结果表明:日粮精料进食水平对瘤胃及全消化道的淀粉表观消化率没有显著影响(P>0.05),日粮精料水平明显影响到达真胃的淀粉量(P<0.05)。     

Concentrate levels and Saccharomyces cerevisiae affect rumen fluid-associated bacteria numbers in dairy heifers

Total viable rumen bacteria counts through the use of colony-unit forming assays lack accuracy because they only include culturable bacteria capable of initiating cell division. Thus, bacterial counts can be underestimated. The use of fluorescent characteristics of cell membranes allows flow cytometry to enumerate and distinguish dead from live bacteria cells. The objective of this experiment was to investigate the viable and total ruminal bacteria counts when 3 levels of forage:concentrate in diets were fed at restricted levels with the addition of Saccharomyces cerevisiae (YC). Three cannulated post-pubertal Holstein heifers (age 18 ± 1.0 months) were fed corn silage (CS)-based diets in a 3-period (35 d) Latin square design. Heifers were fed the diets for 21 d with no yeast addition, followed by 14 d where yeast culture (YC) was added (1 g/kg as-fed basis); (Yea-Sacc¹⁰²⁶, Alltech, Inc., Nicholasville, KY). A low concentrate (LC) TMR (80% CS, 20% concentrate; 12.4% CP, 35% NDF), a medium concentrate (MC) TMR (60% CS, 40% concentrate; 12.3% CP. 28% NDF), and a high concentrate (HC) TMR (40% CS, 60% concentrate; 12.6% CP, 25% NDF), were fed once per day. Rumen fluid was sampled − 2, 0, 2, 4, 6, 8, 10, 12 h after feeding. Samples were immediately stained with fluorescent dyes using the BacLight kit (Molecular Probes Inc., Eugene, OR) and analyzed with a Coulter XL-MCL single laser flow cytometer. Mean rumen viable bacteria counts linearly increased among treatments (4.96, 4.78, 6.73 × 10¹¹ ± 0.53 × 10¹¹ cells/ml; P = 0.02) for LC, MC and HC respectively, and YC addition increased number of viable bacteria cells (P < 0.01). Total and viable bacteria counts decreased for the first 2 h after feeding then increased 4 h post-feeding. Dietary concentrate level and YC can alter rumen bacteria counts as measured by this method.     

顶空气相色谱法检测农药乳油制剂中甲醇含量

建立了农药乳油制剂中甲醇含量快速检测的顶空气相色谱分析方法。以环己烷为内标,采用DB-1701毛细管色谱柱进行分离,氢火焰粒子化检测器(FID)测定。结果表明,该方法在甲醇体积分数为0.1%～1%范围内线性关系良好,回归方程的相关系数为0.999 1,7次平行测定的相对标准偏差(RSD)小于1.33%,空白溶液甲醇的添加回收率在95%～100%之间。该方法简单实用,可以为其他农药液体制剂中易挥发有毒助剂的检测提供参考。     

不同精粗比下添加维生素B12对体外瘤胃发酵和微生物酶活力的影响

本试验通过体外培养法,研究在不同精粗比饲粮中添加维生素B12对体外瘤胃发酵和微生物酶活力的影响。试验采用3×3双因子试验设计,即3个底物精粗比(玉米∶羊草=35∶65、50∶50和65∶35)和3个维生素B12添加量(0、40和90 ng/mL)。体外试验用瘤胃液取自3只安装有永久性瘤胃瘘管的湖羊。体外培养24 h后测定体外瘤胃发酵参数和微生物酶活力。结果显示:1)随着底物精粗比和维生素B12添加量的提高,体外培养24 h的产气量、潜在产气量和有机物消化率极显著地增加(P<0.01),且维生素B12添加量与上述指标存在线性剂量效应(P<0.01)。2)当底物精粗比为50∶50和65∶35时,添加维生素B12显著提高了发酵液中氨态氮、微生物蛋白、总挥发性脂肪酸、乙酸和丙酸浓度(P<0.05),但对丁酸浓度和乙酸/丙酸无显著影响(P>0.05)。3)当底物精粗比为35∶65和50∶50时,添加40 ng/mL维生素B12使发酵液中羧甲基纤维素酶、木聚糖酶活力显著提高(P<0.05);当精粗比为65∶35时,添加90 ng/mL维生素B12使发酵液中羧甲基纤维素酶、木聚糖酶活力显著提高(P<0.05)。结果提示,底物精粗比和维生素B12添加量影响体外瘤胃发酵。添加维生素B12可增加瘤胃微生物酶的活力,从而提高有机物消化率以及微生物蛋白和总挥发性脂肪酸的产量。当底物精粗比(玉米∶羊草)较高(50∶50和65∶35)时,维生素B12的添加效果更明显,并且具有剂量依赖效应。     

水稻纹枯病防治药剂配方筛选及其剂型的研制

以水稻纹枯病菌(Rhizoctonia solani)为供试菌,采用菌丝生长速率法,研究比较了5种新型杀菌剂的室内毒力,并选用高效单剂进行复配研究,明确最佳配比;根据药剂理化性质选用流点法、黏度曲线法和正交试验设计法将混剂加工成对环境友好的水悬浮剂。结果表明:5种杀菌剂中对水稻纹枯病菌的毒力(有效中浓度,EC50)由高到低顺序为:嘧菌酯(0.005 19μg/ml)、已唑醇(0.025 20μg/ml)、戊唑醇(0.209 10μg/ml)、丙环唑(0.349 70μg/ml)、苯醚甲环唑(0.777 10μg/ml);毒力最高的嘧菌酯与己唑醇复配的最佳配比为1∶2(增效系数SR值为1.55);嘧菌酯.己唑醇悬浮剂的最优配方组成为:8.0%嘧菌酯、16.0%己唑醇、2.0%分散剂550s、2.0%农乳404#、0.125%黄原胶、1.5%硅酸镁铝。     

Prefeedîng Plasma Acetoacetate and Glucose in Healthy,Lactating Heifers. Variations Related to Milk Yield,Metabolic Balances and Stage of Lactation

Halse. K. and B. Tveit: Prefeeding plasma acetoacetate and glucose in healthy, lactating heifers. Variations related to milk yield, metabolic balances and stage of lactation. Acta vet scand. 1994, 35,243-255. - When measured before morning feeding plasma acetoacetate (ACAC) increased and glucose (GL) decreased significantly with increasing milk yield (fat corrected, FCM) within 2 groups of half-sister related heifers which did not suffer from clinical ketosis. The groups received respectively A: 7 kg and B: 4 kg/d of concentrates in addition to grass silage ad libitum (each group 88 animals). Correlation coefficients of the same magnitude between the 3 variables mentioned were obtained in the 1st and 3rd month of lactation in spite of a narrowing of the ACAC range from 0.024 - 0.66 to 0.019 - 0.16 mmol/1. Reproducibility of differences between animals in milk yield and in the plasma components was evidenced by significant correlations between measurements in the 1st and 3rd month. The B-animals produced 2.4 kg/d less FCM than the better fed A group (A, 1st month of lactation 19.8 ±3.1 kg/d) while the mean values for ACAC and GL remained practically unaffected by the difference in feeding. B cows gave consistently 5-6 % lower GL means (p< 0.01) than A animals with identical yields.Animals which showed marked ACAC increment during the first 5-6 weeks of lactation produced 3-4 kg more FCM/d than equally fed animals with constantly low ACAC levels. The estimated energy deficit of this ketonaemic, high-producing category corresponded to the production of 4.5 - 6 kg FCM/d from body reserves. Low ACAC values (<0.05 mmol/1) were reproduced with a standard deviation of ± 4% with the automated nitroprusside method described.     

30%代森锰锌悬浮剂的研究

本文简述了30%代森锰锌悬浮剂助剂最佳配方的研究和田间药效试验，及其应用前景。