Leaf litterfall concentrations and fluxes of elements in deciduous tree species

The influence of tree species and soil properties on leaf litterfall concentrations and fluxes of elements were studied in three mixed deciduous forest stands. Leaf litterfall fluxes of sixteen elements were measured during autumn defoliation in 100 to 150 yr old individuals of Fagus sylvatica L., Quercus robur L., Carpinus betulus L., Tilia cordata Mill, and Acer platanoides L. Compared to throughfall and precipitation, leaf litterfall dominated the flux of P, Ca, Mn, N and Mg (in decreasing order) to the soil below the tree canopies. For K and especially S and Na, however, the importance of leaf litterfall input to the total fluxes was small. Fluxes and especially concentrations of Ca, Mg, K, P and partly N were positively related to base saturation of the soil, while Mn was negatively related due to a higher mobilization rate and plant uptake of this element on acid soils. Litterfall fluxes for C. betulus were strongly positively influenced by base saturation and fluxes were usually higher than for F. sylvatica and Q. robur at the richest site. Quercus robur had often the lowest fluxes, especially of Ca and Mg. Tilia cordata had the highest leaf litter concentrations in twelve of the sixteen elements, and the highest fluxes particularly of N and K. Acer platanoides had the highest or among the highest concentrations and fluxes of Ca, Zn and Mn. The concentration of Al in C. betulus leaf litterfall, was about five times higher than in all other tree species at all sites.     

热带地区时间序列土壤中伊利石类矿物的演化——P.Barré假设在热带地区土壤中也存在吗?

P.Barré等认为温带地区自然土壤中,由于植物根系将下层土壤中的钾和硅向上搬运,减缓了上层土壤中伊利石类矿物(混层伊利石/蒙皂石+伊利石)脱钾和脱硅过程,致使其长时间地存在较多的伊利石类矿物。本文旨在了解热带地区土壤中这一假设是否也存在,以海南琼北地区发育于由不同年代火山喷发形成的玄武岩所构成的时间序列土壤(1×104a,(9.0±2.0)×104a,(14.6±0.9)×104a,64×104a,(133±18)×104a,(181±8)×104a)为对象,利用X-射线衍射(XRD)技术分析了其黏土矿物的变化情况,结合土壤钾、硅、活性硅的分析结果,发现伊利石类矿物仅存在于(133±18)×104a以前的土壤中,表层土壤中钾和硅的含量高于下层的土壤,活性硅含量随成土年龄而降低。为此,我们认为:P.Barré假设在热带土壤形成发育过程中,在具有一定的生物复钾和复硅条件下,在成土初期也会存在,但最终会由于土壤强烈的脱钾和脱硅作用而逐步消失。     

不同类型添加材料在新型肥料生产中的应用

就目前新型肥料研制过程中所选用的添加材料或包膜材料进行了归类划分,并对高表面活性矿物、高分子聚合物、抑制剂等材料的化学性质、与肥料养分离子相互作用机理等进行了分析和阐述。分析了不同材料对肥料的溶出速率或释放速率的影响,从提高营养元素有效性和生态环境建设方面讨论了这些材料的应用前景。     

Experimental studies on the impact of an increased dose of anionic salts on the metabolism of dairy cows

Summary

This study was initiated to investigate the influence of a daily dose of anionic salts (AS) above the valid upper limit at present on metabolism of dairy cows. Eleven non‐pregnant and non‐lactating Holstein‐Friesian crossbred cows with a permanent rumen cannula were used in a study with a controlled feeding design. The initial daily dose was 2500 meq/day, which resulted in a Dietary Cation Anion Difference (DCAD) of ‐211 meq/kg dry matter. Every seven days, the daily dose was raised by 500 meq. If a cow stopped eating, the application of AS was stopped and these cows were monitored over the next seven days. On day 30 another batch of hay, having the same DCAD but higher concentrations of minerals and energy, was fed. Blood and urine samples were taken to monitor acid‐base balance and calcium concentrations. Acid‐base balance was strongly influenced by AS. Blood pH dropped steadily and reached values around 7.23. Urine pH dropped quickly below 6 and remained at that level regardless of the increased dosage of AS. Net acid base excretion (NABE) fell continuously with the increase of the dosage of AS and reached values below ‐200 mmol/l. Calcium concentrations in the serum were nearly stable, but those in urine increased sharply and remained on an elevated level with increasing doses of AS. A few days before the individual cow's refusal of feed intake, calcium excretion in urine decreased. The majority of cows stopped eating while consuming a diet containing 3500 to 4000 meq AS except two animals who consumed up to 6000 meq/day AS but they received the better hay in the second half of the treatment period. In this time pH in blood increased slowly. NABE remained stable on a low level at ‐100 mmol/l. The results showed that with an increasing amount of AS fed the risk of clinical acidosis increased. The decreasing urine concentrations of calcium indicate a breakdown of the compensation capability of the single cow. Besides the dose of AS fed, the quality of the feed stuff might be another factor concerning the tolerance of cows against AS.     

20～35kg杜泊×小尾寒羊F1代公羔钙、钠、钾和镁生长需要量

本试验旨在探讨20 ～ 35 kg杜泊×小尾寒羊F1代杂交公羔羊钙、钠、钾、镁生长需要量.采用比较屠宰试验,分别在羔羊体重20、28和35kg时屠宰,测定动物体组织器官的钙、钠、钾、镁含量,建立数学模型对体内矿物质含量变化规律及需要量进行预测.结果显示,羔羊在20 ～ 35kg体重阶段,肌肉生长速度较稳定,骨骼生长速度逐渐减慢,而体内脂肪组织在迅速增加;羔羊体内矿物质含量与空腹体重(EBW)具有高度相关性(R2=0.84 ～0.98),钙、钠、钾、镁净生长需要量(NRG)预测公式分别为NRGca=15.26EBW-0.171,NRGNa=1.67EBW-0.085,NRGK=1.94EBW0.023和NRGMg=0.34EBW0.051.由此可计算得出,杜泊×小尾寒羊F1代羔羊在20～35kg阶段,以空腹体增重(EBG)表示,机体钙、钠、钾、镁的NRG分别为8.56 ～9.36 g/kg EBG、1.15 ～ 1.20 g/kg EBG、2.07～2.09 g/kg EBG和0.39 ～ 0.40 g/kg EBG;以体增重(BWG)表示,分别为7.18～8.18 g/kg BWG、0.96 ～ 1.05 g/kg BWG、1.76～1.81 g/kgBWG和0.34 g/kg BWG.     

Feeding value of pastures for horses

The feeding value of fresh pasture grazed in situ is determined by animal performance or productivity and could be relatively easily established for growing and lactating horses. Despite this, there is a lack of published information on the relative feeding value of different pastures and forages grazed by horses in New Zealand and the world. In addition, for adult breeding or non-breeding and young or adult sport or performance horses, the definition of feeding value and its determination remain problematic.

Limited information suggests that the feeding value of perennial ryegrass-based pasture in New Zealand for young growing horses is high, and growth rates for Thoroughbred horses fed solely on pasture in New Zealand are similar to those reported from the Northern Hemisphere where grain-based supplements are fed in addition to pasture or other forages. Attempts to assess the ability of fresh pastures to meet the nutrient requirements of horses are hampered by problems associated with determination of feed intake by grazing horses and lack of knowledge of the digestibility and utilisation of digested nutrients, including the relative bio availability of macro- and micro-minerals in pasture. A further challenge for future research is to determine the effect of herbage allowance and grazing behaviour, including pasture species preferences, on voluntary feed intake by grazing horses.

Grazing pasture has benefits for equine health and well-being including reduced risk of some nutrition-related disorders and reduced prevalence of stereotypic behaviour. Pastured horses have greater freedom for expression of natural behaviours including social interaction and exercise. However, grazing pasture is also associated with animal health problems, particularly parasitism and diseases related to pasture-associated toxins.     

Random-effects linear model application to herd-level assessment of bovine hepatic trace mineral concentrations

To evaluate the utility of random-effects linear modeling for herd-level evaluation of trace mineral status, we performed a retrospective analysis of the results for trace mineral testing of bovine liver samples submitted to the Michigan State University Veterinary Diagnostic Laboratory between 2011 and 2017. Our aim was to examine random-effects models for their potential utility in improving interpretation with minimal sample numbers. The database consisted of 1,658 animals distributed among 121 herds. Minerals were assayed by inductively coupled plasma–mass spectroscopy, and included cobalt, copper, iron, molybdenum, manganese, selenium, and zinc. Intraclass correlation coefficients for each mineral were significantly different (p < 0.001) from zero and ranged from 0.38 for manganese to 0.82 for selenium, indicating that the strength of herd effects, which are presumably related to diet, vary greatly by mineral. Analysis of the distribution and standard errors of best linear unbiased predictor (BLUP) values suggested that testing 5–10 animals per herd could place herds within 10 percentile units across the population of herds with 70–95% confidence, the confidence level varying among minerals. Herd means were generally similar to BLUPs, suggesting that means could be reasonably compared to BLUPs with respect to the distributions reported here. However, caution in interpreting means relative to BLUPs should be exercised when animal numbers are small, the standard errors of the means are large, and/or the values are near the extremes of the distribution.     

微量元素调控鸡蛋蛋壳品质的研究进展

蛋壳品质是蛋鸡生产中重要的经济性状和外观性状指标。蛋壳品质降低导致的蛋壳破损问题会给家禽生产和蛋品加工业造成巨大的经济损失。微量元素不仅是蛋壳的化学组成成分,也可参与调控蛋壳晶体结构的形成,进而影响蛋壳的力学特性。本文基于饲粮中微量元素的水平和来源的合理选用这一实际问题,对几种主要微量元素调控蛋壳品质的最新研究进展进行了综述,为进一步研究和应用提供借鉴。     

More than eating dirt: a review of avian geophagy‡

Geophagy, the ingestion of earth varying in particle size from stones to soils rich in clay, is a relatively widespread behaviour across avian taxa. We reviewed its occurrence in birds and its hypothesised adaptive functions in birds. Of the ～30 avian orders, 23 exhibit geophagy. However, it has only been documented in ～260 species (～2% of birds) and therefor is relatively uncommon. Ingestion of stones and other large particles (grit) is recorded in 54 extant families across the avian phylogeny and appears to be ancient in birds and has evolved several times. Clay ingestion is recorded in 14 phylogenetically scattered families and might have evolved repeatedly. Furthermore, at least nine families exhibit both clay and grit ingestion. Six hypothesised functions of avian geophagy involve digestion and nutrition. Ingested grit might provide (1) essential minerals, particularly sodium or calcium, but it appears to primarily (2) improve mechanical digestion of food in the gizzard, where ingested stones and sand particles are known as gastroliths. Consistent with this gastrolith hypothesis, ～86% of species ingesting grit consume “hard” food: seeds, leaves, insects or other animals. In contrast, ingested clay appears to be for sodium or other nutrient intake and/or protecting birds from ingested plant secondary compounds, by (3) protecting the digestive tract and (4) adsorbing these compounds. Consistent with this, ～88% of species ingesting clay eat fruit that is often rich in secondary compounds and low in sodium, and clay ingestion is associated with frugivory in a representative sample of genera of which many have been shown to source sodium. The other two hypotheses are buffering gastric pH (5) and acquiring antidiarrheal agents (6), but no documentation of this in birds was found. We suggest additional tests of these hypotheses and additional investigation of these proposed benefits of geophagy in birds.     

Organic trace minerals on productive performance,egg quality and immune response in Bovans White laying hens

This study was performed in 360 laying Bovans White hens and aimed to evaluate the effect of Carbo‐Amino‐Phosphate‐Chelates (CAFQ) as a mineral premix and its 30% reduction by compared to inorganic trace minerals (ITM) concerning its performance, egg quality, tibia breaking strength and immunity. Sixty‐week‐old hens were assigned into three treatments with 10 replicates of 12 birds each. Treatments were as follows: (a) (100% ITM), (b) (100% CAFQ) and (c) (70% CAFQ). Based on the results obtained during 12 weeks, under the current test conditions, improved yolk colour (p < 0.05); shell breaking strength (p < 0.05); and storage time (p < 0.05) were observed in hens fed with a diet reduced by 70% in CAFQ inclusion showed similar performance behaviour and better egg breaking strength regarding with ITM, suggesting the possibility of minimizing the inclusion of trace minerals in laying hen diets improving environmental impact, in contrast to the use of inorganic sources of minerals.