不同月龄纯种和牛主要血液指标变化规律的研究

目前我国对和牛血液指标基本情况的报道较少,本研究测定并对比了不同月龄纯种和牛血液指标变化规律。结果表明,不同月龄纯种和牛血清中β-胡萝卜素含量在1.29~2.64μg/mL之间,γ-谷氨酰转移酶(γ-GTP)含量在19.95~26.81UI/L之间,维生素A含量在37.00~56.74ng/mL之间。     

The effect of sex and age on caffeine pharmacokinetics in cattle

The aim of this study was to determine the effect of sex on the pharmacokinetics of caffeine in cattle at different ages. Ten female and 10 male Holstein cattle were subject to a caffeine test when they were aged 1, 2, 4, 6, 8, 12 and 18 months. Caffeine, 5 mg kg(-1)body weight, was given intravenously as a sterile isotonic solution. An automated, enzyme-multiplied, immunoassay technique (EMIT) was used to determine plasma caffeine concentration. The volume of distribution of caffeine (V(SS)) decreased significantly between 1 and 18 months of life. Mean V(SS)values observed in males and females were not statistically different. The experimental period was characterised by a steady decrease (statistically significant) in caffeine mean residence time (MRT). These values did not differ significantly between males and females under 8 months of age. In 8-, 12- and 18-month-old animals, the caffeine MRT in the females was significantly shorter than in the males. The total plasma clearance (Cl(tot)) of caffeine increased significantly between 1 and 18 months of age. No significant differences were observed between total plasma clearance of caffeine in males and females under 8 months of age. In 8-, 12- and 18-month-old animals, the Cl(tot)of caffeine was significantly higher in females than in males. In conclusion, we report a sex-linked difference in pharmacokinetics of caffeine in cattle over 8 months of age, the females being the more active metabolisers. The results of the present study support the hypothesis that the metabolism of xenobiotics is sexually different in ruminants.     

The effect of an energy additive on the metabolism of cattle

The objective of this study was to determine the effect of an energy additive on the metabolism of cattle. This article provides information on the analysis of the diet of young cattle calculated for when the animals were both indoors and outdoors. The ration was prepared for 40 heifers, divided into 4 groups consisting of 10 animals in each group. Three of these groups were fed different amounts of a high-energy additive, which was not fed to the control group. The effectiveness of the additive was analyzed according to the balance experiment and by calculating digestibility coefficients. It was determined that the percentage of nitrogen use in young animals was higher in the groups that were fed the additive than in the control group. Increasing the dose of the additive increased the level of nitrogen use. Comparative analysis of live weight indicated intergroup differences in favor of heifers in the groups that were fed the additive of 1.34% to 2.41% at the age of 9 mo; 2.51% to 4.16% at 12 mo; 3.14% to 5.46% at 15 mo; and 3.57% to 6.30% at 18 mo. The average daily growth dynamics indicated a gradual increase in all animals up to 15 mo, with a slight decrease by 18 mo of age. The difference among the groups ranged from 5.08% to 8.85% at 6 to 9 mo of age; 7.08% to 10.79% at 9 to 12 mo; 5.64% to 10.97% at 12 to 15 mo; and 6.05% to 11.11% at 18 mo. It was concluded that feeding the energy additive Tanrem to heifers increased their metabolism so that nitrogen use was improved, and feed was digested more efficiently, which in turn improved the growth of animals. Using an energy additive at the mid-range dose of 500 g a day per animal is recommended, since the effect was similar at the mid-range and maximum dosages.     

The effect of tiamulin administered by different routes and at different ages to turkeys receiving monensin in their feed

Healthy turkeys receiving 80 ppm monensin in their feed were injected at 26, 40 and 61 days of age with tiamulin at dosages of 12.5 and 25 mg/kg body weight. The aim of the study was to develop a regime for medicating with tiamulin turkeys receiving monensin in their feed, and which would circumvent the known toxicity created by the simultaneous administration of the two drugs. One injection of 12.5 mg/kg tiamulin up to the age of 61 days or 2 injections of 12.5 mg/kg tiamulin up to 40 days of age caused no mortality or adverse reaction.     

不同日粮对肉牛育肥效果研究

育肥牛试验选用 1 5～ 2 0周岁秦杂阉牛 2 0头 ,随机分为试验组和对照组 (P >0 0 5 ) ,试验期 60d。结果表明 ,试验组日增重 1 2 1kg/头 ,对照组 0 67kg/头 ,试验组比对照组多增加 0 5 4kg ,提高 80 % ,差异极显著 (P <0 0 1)。试验期试验组每头牛利润 185 4 4元 ,对照组每头牛利润 96 2 5元 ,试验组每头牛比对照组多收益 89 19元 ,每头牛日增利润 1 4 9元。     

The effect of changing the sex ratio on the efficiency of cattle breeding operations

The direct effect of sex control in providing a higher proportion of male calves for beef production can increase the beef output of a dual-purpose population by up to 5%. The actual increase depends on the rate of cow turnover and on the net superiority of males over females in the population concerned. Control of the sex ratio also permits an increase in the intensity of selection, particularly in the paths dams-sons and dams-daughters. The total effect could be an improvement of the order of 10% in the rate of genetic change in the population. Thirdly, control of the sex ratio increases the possibilities for beef crossing in dairy or dual-purpose cattle populations. This can increase the beef output of the population by up to 4%, depending on the rate of cow turnover and the superiority of the beef strains used. If these opportunities are pursued they are likely to drive the population into specialised strains of dairy and beef cattle.     

The effect of nitrovin on the kinetics of sulphadimidine in domestic fowl of different ages

In experiment on cockerels, the interaction of sulphadimidine with nitrovin manifested itself in an effect on the distribution of sulphadimidine, and particularly on its bloodlevel; this depended, among other factors, on the age of the animals. At nitrovin medication, the bloodlevels of sulphadimidine were higher, mainly soon after administration, and their drop was quicker than in untreated animals. This effect on the levels of sulphadimidine in the blood was pronounced in three-week-old chickens, whereas in older birds it was feeble or absent. Except the higher level 30 min. after application to.five-week-old chickens given feed with 120 g t-1 of nitrovin, the differences were statistically insignificant. The changes in the concentration of sulphonamide in the liver and kidneys corresponded with the changes observed in the blood; the concentration in muscle was not affected by nitrovin under the given conditions. The favourable effect of nitrovin on weight gains, demonstrated in principle during the experiment, was directly dependent upon the concentration of nitrovin in feed. As to the effect of the length of its administratiion, the three-day administration of nitrovin (before weighing) to cockerels up to five weeks of age had a better influence on gains than administration from the sixth day after the medicated of the chickens. In older cockerels the gains were better in the groups treated for a longer time, i. e. from the sixth day from hatching.     

Effect of different volatile fatty acids mixtures on energy metabolism in cattle

Four Friesian steers (mean BW = 282 kg) were given mixtures of VFA and casein by intragastric infusion to give a total energy input of 675 kJ/kg BW.75. Casein supplied 16.3% of the energy and 777 mg N/kg BW.75. The molar proportion of butyric acid was held constant at 8 mol/100 mol, and the acetic and propionic acids varied inversely. Acetic acid was varied in 12 increments from 11 to 91 mol/100 mol and propionic acid proportion varied inversely. Heat production, blood (urea, insulin, beta-hydroxybutyrate, free fatty acids) and urine metabolites (urea, N, VFA) were measured. There were no differences (P greater than .05) in heat production until the acetic acid proportions exceeded approximately 90 mol/100 mol, at which point there was a decrease in heat production (P less than .05) accompanied by a considerable excretion of acetic acid in the urine. Above 80 mol/100 mol acetic acid, beta-hydroxybutyrate was greatly elevated, accompanied by a small decrease in blood glucose and blood insulin together with an increase in blood free fatty acid concentration. There was also an elevation of N excretion in the urine. When the proportion of propionic acid exceeded 76 mol/100 mol there were some metabolic disturbances resulting in blood hemolysis, an increase in N excretion in the urine, and nervous disposition of the animals. It is concluded that differences in heat production between roughage and concentrate diets are not likely to be a result of differences in the energetic response to different proportions of VFA. Differences in activity during standing, feeding, and ruminating may, therefore, be more important.(ABSTRACT TRUNCATED AT 250 WORDS)     

催乳素对奶牛脂肪细胞脂代谢关键基因的作用

催乳素(prolactin,PRL)是启动和维持泌乳的重要激素,在泌乳期间能调节机体将营养物质和能量优先流向乳腺,用于乳脂和乳蛋白的合成。本试验采用体外分离培养奶牛前脂肪细胞,诱导分化为成熟脂肪细胞,加入PRL探讨其对脂肪细胞脂代谢相关基因的作用。结果显示,奶牛白色脂肪细胞存在催乳素受体(prolactin receptor,PRLR),且在PRL质量浓度为75μg/L,作用时间为9h时,PRLR表达量达到最高,此时调节脂合成的核转录因子SREBPE-1c及下游控制脂合成的基因FAS和LPL均显著降低,75μg/L组与对照组相比差异极显著(P0.01);控制脂分解的基因HSL显著升高,75μg/L组与对照组相比差异显著(P0.05);细胞培养上清液中的甘油含量显著升高,75μg/L组与对照组相比差异显著(P0.05)。结果表明,PRL能直接作用于奶牛白色脂肪细胞,降低脂合成作用并促进脂分解作用。     

The effect of Rumensin on mineral metabolism and on the conversion of nutrients in feedlot cattle

A study on mineral metabolism and conversion of nutrients by applying sodium monensinate, 125 mg per head and day, in cattle fattening was performed. This experiment was realized under production conditions in the fattening station of pavillion type for 367 days and included 985 bulls of Bohemian Spotted cattle. The feed ration consisted of maize silage with addition of dried poultry bedding and concentrates. At the beginning of the experiment the appetite antipathy was observed, the adaptation period lasted 4 weeks. During the adaptation period the weight gains decreased; after adaptation of animals to monensin the weight gain not only counter-poised, but in comparison with the control it increased. Throughout the experiment no health disorders connected with the applied additive were observed. In the rumen fluid the content of calcium, magnesium, phosphorus, zinc, copper and iron was followed. In the blood plasma the levels of sodium, potassium, calcium, magnesium, phosphorus, zinc, copper and iron were followed. The application of sodium monensinate did not affect the followed parameters of mineral metabolism. The experiment was aimed at the evaluation of production and operational parameters with a view to the weight gain and feed conversion. In the experimental group the weight gain was higher by 3.85%. The saving of maize silage in the experimental group amounted to 5.8%, by using of this additive the saving of concentrates amounted to 1.35%. In the experimental group the feed conversion converted to dry matter increased by 7.12%. Sodium monensinate at the dose of 125 mg per head and day had positive effect on the followed production and economic parameters.     

Effects of age, sex and breed on antipyrine disposition in calves

In domestic animals relatively little is known about the functions of hepatic microsomal enzymes and their role in biotransformation. In this study, antipyrine was used to assess microsomal oxidative function and particularly to determine the effect of age, sex and breed on drug metabolising enzymes. At birth, the elimination rate of antipyrine was very low as reflected by a half-life of 24 hours. The first two months of life were characterised by a steady decrease of antipyrine half-life values of three to four hours being reached at six months. The decrease observed during early life was not identical in the two breeds used in this experiment. By six months the Friesian calves eliminated antipyrine twice as fast as the Blue White Belgian (BWB) breed: 2.1 +/- 0.3 hours and 4.9 +/- 0.3 hours, respectively. The BWB breed is characterised by muscular hypertrophy and by a relative imbalance in muscle:body ratio. The apparent volume of distribution of antipyrine did not vary with age, sex and breed. No differences in antipyrine clearance were found between male and female calves.     

The effect of Rumensin on the health status and energy metabolism of feedlot cattle

The effect was studied of sodium monensinate dosed 125 mg pro die and given to feeder cattle on the health condition and some clinico-biochemical parameters in view of the energy metabolism. The experiment was performed under current farming conditions in a pavilion fattening house. The experiment, which lasted 367 days, was conducted with 985 bulls of the Bohemian Spotted breed. Ten animals from the experimental and ten animals from the control pavilion were subjected to detailed clinical and clinico-biochemical examination. The feed ration was based on corn silage with an additive of dried poultry litter and concentrates. The additive was administered in the concentrate mixture, 125 mg per head/day. The health condition of the bulls was good during the whole period of study, and except several cases where neck chain wounds were observed, or small traumatic alterations on the extremities, no health disorders occurred. Some clinico-biochemical parameters of the blood were followed to study the metabolic processes and health condition. pH, pCO2, BE, SB were studied to find out the acid-base relations of the blood. As to the energy metabolism, the levels of glucose, total protein, urea, nonesterified fatty acids, triglycerides, cholesterol and total lipids were followed. Among other hematologic parameters studied there were hemoglobin, hematocrit, beta-carotene and the levels of glutamate-oxalacetate transaminase and glutamyl-transpeptidase in relation to liver metabolism. During the period of study, increased urea levels were found in the experimental animals, and on the other hand lower levels of free fatty acids and triglycerides in the blood serum. No significant changes in the other studied parameters were observed in the course of the experiment. It can be stated according to the obtained results that sodium monensinate did not influence negatively the studied clinico-biochemical parameters nor the health condition.