Premature Disposal Research Articles

Age and lactation specific disposal pattern in Sahiwal cattle and influence of various genetic and non-genetic factors

Premature disposal of female calves before reaching milch herd and undesirable disposal of lactating cows are the major constraints in achieving larger herd size. During the early lactations, younger cows are supposed to give higher milk yield and undesirable disposal of early calvers, thereby, greatly hampers profitability of a dairy farm. Knowledge of the incidence of disposal along with reasons in various age groups and at various parities is essential to identify which age group or parity is more vulnerable for disposal. Moreover, knowledge of various genetic and non-genetic factors associated with disposal of animals may also be helpful in developing breeding and management strategies to reduce the incidence of disposal. In most of the studies, it was found that major reasons of disposal of dairy cattle were mortality among female calves and involuntary culling among adult lactating cows. Maximum mortality in female calves was observed during earlier ages and pneumonia, gastro-enteritis and debility were major reasons of female calf mortality. Whereas, most of the adult cows left the herd, due to teat and udder and reproductive problems. Moreover, indigenous breeds were found to be more adapted to Indian tropical climatic conditions in comparison to crossbred and exotic cattle breeds.

脊椎动物传播植物肉质果中的次生物质及其生态作用

PDF HTML阅读 XML下载 导出引用 引用提醒 脊椎动物传播植物肉质果中的次生物质及其生态作用 DOI: 10.5846/stxb201212151805 作者: 作者单位: 南京林业大学森林资源与环境学院,南京林业大学森林资源与环境学院,南京林业大学 森林资源与环境学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金面上项目（30970470）；江苏高校优势学科建设工程项目 Secondary substances and their ecological effects on seed dispersal in vertebrate-dispersed fleshy fruit plants Author: Affiliation: College of Forest resources and Environment,Nanjing Forestry University,College of Forest resources and Environment,Nanjing Forestry University,College of Forest resources and Environment,Nanjing Forestry University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:在种子植物-动物的互惠关系中，植物果实成熟后需要吸引种子传播者取食果实，传播其种子至适宜萌发的生境，同时又要防御种子捕食者过度消耗种子。果实内的次生物质（如：配糖生物碱、大黄素、辣椒素）在此过程中起到重要的调控作用。依赖脊椎动物传播的肉质果中往往含有与植物茎、叶内相同的次生物质，其种类繁多，主要分为含氮化合物、酚类化合物和萜类化合物。未成熟果实内富含次生物质（如：单宁、大黄素），主要保护未成熟种子不被潜在的捕食者和食果动物取食，这些次生物质的含量通常随果实成熟而降低；其它次生物质（如：脱辅基类胡萝卜素）的含量随果实成熟而增多，可能起到吸引食果动物的作用。在对脊椎动物捕食的抵御中，果实内不同类型的次生物质促使成熟果实对所有脊椎动物都有毒性（专毒性）或者仅对种子捕食者有毒性（泛毒性）。肉质果内的次生物质对植物-食果动物相互关系的调控作用，还可以通过调节动物取食频次和数量、抑制和促进种子萌发、改变种子在肠道的滞留时间、吸引传播者等生态作用而实现。某种次生物质往往集多种生态作用于一身。目前对肉质果内次生物质与脊椎动物相互关系的探讨还不够深入。未来研究需要综合考虑植物次生物质与果实生理生化、形态学等特征对食果者的综合调控机理；次生物质在种子传播后的调控作用对植物种群或群落结构和分布格局的影响；从动植物协同进化角度探讨植物次生物质的产生、防御和吸引策略与脊椎动物对果实的选择和消费之间的关系等。开展脊椎动物传播肉质果实中次生物质的研究，对完善种子传播机制、植物繁殖和更新格局，丰富动植物相互作用、协同进化理论具有重要的意义。 Abstract:Plant species which depend on vertebrates for dispersing their seeds in flesh fruits to safe sites for establishment often face the trade-off between attracting seed dispersers and preventing their seeds from over consumption by seed predators. Secondary substances such as glycoalkaloids, emodin, and capsaicinoids in fleshy fruits play an important role for regulating this process. There are diverse secondary substances in vertebrate-dispersed fleshy fruits, but they are often the same as those found in the stems and leaves, and mostly belong to the three major categories: nitrogen-containing compounds (e.g. glycoalkaloids and capsaicinoids), phenolic compounds (e.g. emodins and tannins), and terpenoids (e.g. saponins). The content of some secondary substances such as tannins and emodins is abundant in immature fruits, which deters the potential predators or pre-mature disposal by frugivores; the content decreases with the fruit maturity. Other secondary substances (e.g. apocarotenoids) increase with the maturation, which may promote the consumption by dispersers. Secondary substances in vertebrate-dispersed fleshy fruits may modify the relationship between animals and plants by altering the fruit consumability: depending on the type of the secondary substances, the fleshy fruits could be toxic to all vertebrates (non-specific or general toxic) or only to some species (specific or directed toxic). Secondary compounds might be able to regulate animal feeding frequency and the amount of consumption by causing frugivores to leave the fruit plant sooner in a foraging bout; early departure from the plant might reduce the number of fruits consumed by a particular animal, but may increase the overall the likelihood of seed dispersal away from parent plant by other dispersers. Secondary substances in ripe fruit pulp can inhibit pre-dispersal seed germination or enhance post-dispersal seed germination. Gut retention time of seeds in vertebrates could be altered by some secondary substances, permitting either more rapid passage via laxative effects or slower passage rates by constipating effects. The colors, odors, and flavors of the fleshy fruits can be modified by secondary substances, which can attract dispersers by providing foraging and rewarding cues recognized by frugivores. A single secondary substance can have multiple ecological functions. Our knowledge of secondary substances in flesh fruits and their interactions with vertebrate animals are still limited. Future research need to consider diverse aspects of plant secondary substances such as the comprehensive regulatory mechanisms of fruit physiological biochemistry and morphology characteristics to the frugivores; the regulatory mechanisms of secondary substances for plant population and community structure and distribution patterns post dispersal; and the coevolution between the production of secondary substances and their defense and attraction strategies of plants and the selection and consumption of fleshy fruits by vertebrate animals. The research of secondary substances in vertebrate-dispersed fleshy fruits will enhance our knowledge of seed dispersal mechanisms, plant generation and recruitment patterns, and animal-plant interaction and their coevolution. 参考文献 相似文献 引证文献

Immunization against Paratuberculosis - Current Perspectives

Johne’s disease is chronic progressive enteritis of domestic and wild ruminants caused by Mycobacterium avium subsp. paratuberculosis. Organism is very sturdy in environment and young animals are more susceptible to the disease from infected carriers via contaminated milk, feed and colostrums. For the dairy industry, economic losses from Johne’s disease are primarily due to premature disposal of animals and reduced milk production. Therefore, a vaccine that prevents animals from becoming infected would be an ideal goal and there is no proper test for the diagnosis, it is prudent to control the disease by immunization. There are mainly three types of vaccine, which are killed, modified live and subunit vaccine. Current vaccines could reduce the severity of infections but they are all failing to give sterile and long lasting immunity. So it is imperative that experimental studies should be conducted to produce an ideal vaccine candidate against MAP.

‘What I’ve found is that your related experiences tend to make you dissatisfied’: Psychological obsolescence, consumer demand and the dynamics and environmental implications of de-stabilization in the laptop sector

Research on product life-spans tends to link the causes of psychological obsolescence with end-users and product designers, and posits the consequences of obsolescence in terms of increasing e-waste and energy use. Drawing upon qualitative fieldwork conducted with employees of a global computer firm and users of its laptop computers this article brings together the poles of production and consumption to explore the dynamics of de-stabilization in product qualities, connecting the intensification of this process to psychological obsolescence and unsustainable patterns of consumption. First, we demonstrate that consumer-facing functions within the firm such as user research, sales and marketing play a key role in driving the pace of technological change within the firm by specifying consumer demand. We argue that by distilling an imaginary demanding consumer from various sources, the firm justifies and drives rapid de-stabilization in product qualities and specifications. We show how this prompts end consumers to constantly re-evaluate product qualities, devaluing existing products and contributing to psychological obsolescence and disposal of functioning products. We then go on to discuss the environmental implications of this process, suggesting that whilst premature disposal due to perceived obsolescence may not increase waste in the short term, it is still likely to contribute to an increase in material and energy use in manufacturing.

Genetic analysis of clinical mastitis in different risk periods by linear and threshold models

Understanding the genetic basis of clinical mastitis (CM) during lactation is essential in deciding on the best measure of CM for breeding value evaluation. CM is one of the leading reasons for premature disposal of dairy cows. Culled cows have incomplete lactation records, and in statistical analysis this may cause sampling biases, because culled cows are seldom a random sample. It is, therefore, essential to study the effects of culling information on the genetic analysis of CM. The objectives of this study were first: to estimate heritability and genetic association between CM during the different stages of first lactation using linear and threshold models, second: to assess the effects culling information on the estimates of variance (co)variance components and associated genetic parameters. First lactation was divided into six lactation stages (risk periods) by days (d) after calving: CM1, (-7 to 150 d); CM2, (-30 to 30 d); CM3, (-30 to 150 d); CM4, (31 to 150 d); CM5, (150 to 300 d); CM6, (-30 to 300 d). To assess the effect of including or excluding records of cows that had been culled from the herd before the end of the risk period, two data sets were prepared. In the first data set (Data I), records of cows culled before the end of the risk period were not included. In the second data set (Data II), records of cows culled during the risk period were included; if the cow had been culled for mastitis reasons or had completed two-thirds of the opportunity period if culled for other reasons. Variance (co)variance components were estimated by linear and threshold-liability models employing Bayesian approach. Heritability estimates using the linear model ranged from 0.005 to 0.024 for Data I, and from 0.005 to 0.029 for Data II, depending on the stages of lactation or risk period defined. The corresponding estimates from the threshold-liability model ranged from 0.034 to 0.076, and from 0.043 to 0.083 for Data I and Data II, respectively. In general, increased sire variance and higher heritability were observed with the inclusion of culling information. Estimated genetic correlations between the CM traits were medium to high, and ranged from 0.42 to 0.99 in Data I, and from 0.61 to 0.99 in Data II. Thus CM cannot be regarded the same trait in the course of lactation. Results from the threshold analyses showed that the heritability of liability to CM was highest for CM2 and followed by CM6, CM3 and CM1with estimates of 0.083, 0.073, 0.073 and 0.072, respectively. Estimates for CM4 and CM 5 were the lowest with heritability of 0.043 and 0.047, respectively. The high heritability estimate for CM2 indicates that most genetic information is in early lactation. Thus, the best measure of CM would be to consider only cases in early lactation. However, as the genetic correlation between CM traits defined over the different risk periods were less than one, mastitis cannot be regarded as the same trait in the different parts of lactation. Thus, a multivariate model, treating mastitis in different stages of lactation as different traits, would be the best model for sire evaluation.

The financial and production impacts of bovine dermatophilosis in Zambia

During October to December 1986, 365 traditional cattle herds in four provinces in Zambia were inspected and the owners interviewed. Information was collected on the treatment, management and disposal of cases of bovine dermatophilosis and on the effects of this disease on productivity for 1985. The contemporary financial cost per case of treatment and/or premature disposal, slaughter or death to the owners was K. 202 (US$91). The cost due to draft oxen being affected was estimated at K. 428 (US$193) per affected ox. The cost of reduced milk production, replacing affected cows and calf deaths, directly or indirectly from bovine dermatophilosis, was estimated at K. 132 (US$78) per affected milking cow. The total annual national cost of bovine dermatophilosis in 1985 was conservatively estimated to be some K. 6.9 million, (US$3 million). There were indications that the true financial cost in 1985 may have been up to 1.8 times the estimated cost.

Sow replacement: A comparison of farmers' actual decisions and model recommendations

Sow culling data were analyzed from 1617 culled sows on 12 Dutch farms, using the VAMPP herd health and management information system. The annual culling rate was found to be 50%, more than half of which was due to reproductive problems and low productivity. The risk of removal increased considerably with age, except for second parity sows. The data were economically evaluated, using the PorkCHOP replacement model. The calculated losses caused by premature disposal turned out to average Dfl. 124 per culled sow, or Dfl. 9300 per year in a 150-sow operation, which equals about 16% of pig farm income. The highest economic losses were found in cases of “lameness/leg weakness”, averaging Dfl. 183 per culled sow. In comparing the model recommendations and the actual decisions to cull sows because of low productivity there was a striking resemblance. Culling the elder, poorly producing sows directly after weaning was the right decision economically. With respect to reproductive problems, however, sows showing no heat were culled too early after weaning and sows that failed to conceive too late. Moreover, the time of culling hardly differed with the sow's age and productive performances. Further research is desired to determine whether computerized decision support can help the farmers to reduce the income losses when sows fail to conceive.

Economic losses due to paratuberculosis in dairy cattle.

The results of a study of the economic losses caused by paratuberculosis in dairy cattle are reported. The losses in production and the determination of lost future income due to premature disposal are emphasised. A decrease in milk production of 19.5 per cent compared with the lactation two years before culling was recorded in animals showing clinical signs of paratuberculosis. The decrease in production in the last lactation but one compared with the previous lactation was 5 per cent. In animals with non-clinical forms of paratuberculosis these decreases in production were 16 per cent and 6 per cent, respectively.

Economic optimization of culling strategies in swine breeding herds, using the “porkchop computer program”

A computer model, PorkCHOP, has been designed (i) to quantify the benefits of increased lifespan in swine breeding herds and (ii) to optimize the replacement decision for sows with poor productive and/or reproductive performance. The model has been constructed in an electronic spreadsheet program for a microcomputer. It runs with default values, but allows the user to enter other data for all the variables considered, and therefore can easily be adjusted to individual farm conditions worldwide. In addition to research and teaching, the model is suitable for use in the field. PorkCHOP introduces a new economic index to use as a culling guide. This index is called the Retention Pay-Off (RPO), and indicates the total extra profit which retention of a sow is expected to yield over replacement, taking into account the risk of premature disposal. This index makes it possible to rank sows within the herd on future profitability. A value below zero indicates that replacement is the most profitable choice. Furthermore, the index is used to determine when to stop breeding if sows fail to conceive. The current (parity-specific) default values are chosen to be typical of U.S. herds with continuous farrowing and standard management practices. For herds in confinement under these conditions, some of the results obtained were: 1. (1) An economic optimum herd life of 10 parities for average producing sows. 2. (2) An increase in income between $17 and $31 per sow per year if the average parity at removal could be increased from 3.6 to 4.6. 3. (3) A financial loss of $1.33 per day delay in conception. 4. (4) First parity sows with a litter size of even 50% below average should not be culled on economic grounds. 5. (5) Average producing sows in the 1st, 2nd and 3rd parity can fail to conceive at least 3 times before replacement becomes the more profitable alternative. However, if reccurent fertilty problems are expected in future parities too, only 1 re-breeding is economically worthwhile. Sensitivity analyses showed that the results obtained differ according to the price and production circumstances involved. As big differences in these parameters occur between farms as well as between years within farms, a computerized approach such as PorkCHOP can greatly improve management decisions regarding sow-replacement.

On the retention of finished goods inventory when reorder‐occurrence is uncertain

AbstractFinished goods inventory may accumulate for a variety of reasons in the production of lowdemand or slow‐moving items. In this article a simple model is developed and some results are presented to aid in making inventory retention decisions when there exists uncertainty about whether reorders for a slow‐moving item will be received in the future. In formulating the model, it is assumed that some excess inventory remains after filling a customer order and that a single reorder for the item is possible. The problem is to determine how long to retain the inventory before disposing of it.The relevant expected costs of retaining some quantity of inventory for a period of time consist of two types: (1) the inventory carrying cost less the salvage value from disposal; and (2) the future production cost incurred due to premature disposal. Using conventional optimization, a relationship for finding the optimal retention period is derived and conditions are identified that ensure that the optimal retention period can be obtained directly from the relationship.To determine the optimal retention period, probability distributions are required for the interarrival time until the reorder occurs and for the reorder quantity. While it seems logical to assume that each item would have its own distributions, this argument leads to a specification problem since the data needed to establish distributions for individual items will generally not be available for slow‐moving items. One approach used to overcome this problem in practice is to combine data for a selected group of items and use the combined data to obtain distributions useful for any or all of the items in the group. An example illustrating this approach is provided.