bluuebunny/crossref_metadata_2025 huggingface dataset:
New visions in specific immunotherapy in children: an iPAC summary and future trends
Authors: Halken Susanne , Lau Susanne , Valovirta Erkka
Published: July 2008

Specific immunotherapy is indicated for confirmed immunoglobulin E‐mediated airway diseases using standardized allergen products with documented clinical efficacy and safety. For decades the subcutaneous route of administration (SCIT) has been the gold standard. Recently, the sublingual immunotherapy (SLIT) has also been investigated in children. SCIT, especially with grass and birch pollens but also house dust mites, is an effective treatment in children with allergic rhinitis and asthma when a significant part of their symptoms are caused by these allergens. A long‐term effect up to 12 yr after discontinuation of SCIT with timothy allergen has been shown. Efficacy and safety of SLIT in pollen allergic rhinoconjunctivitis have been demonstrated in adults. The evidence in children is a little less convincing, and more data is needed. The clinical relevance, long‐term results and the size of the effect, as well as the dose, the treatment regimen and duration has not been sufficiently elaborated. It is demonstrated that SCIT has the potential for preventing the development of asthma in children with allergic rhinoconjunctivitis. Also one randomized study indicates a preventive effect of SLIT in children on the development of asthma. At present, there are no studies who clearly demonstrates either a long‐term effect or a preventive effect on the development of asthma of SLIT in children. The areas with lack of evidence should be addressed in well performed prospective, randomized long‐term studies both with SCIT and SLIT. This review was initiated by iPAC (international Pediatric Allergy and Asthma Consortium) and aims to review current knowledge related to specific immunotherapy in childhood, and to identify needs for future research in this field.
Photosynthetic activity during olive (Olea europaea) leaf development correlates with plastid biogenesis and Rubisco levels
Authors: Maayan Inbar , Shaya Felix , Ratner Kira , Mani Yair , Lavee Shimon , Avidan Benjamin , Shahak Yosepha , Ostersetzer‐Biran Oren
Published: July 2008

Olive leaves are known to mature slowly, reaching their maximum photosynthetic activity only after full leaf expansion. Poor assimilation rates, typical to young olive leaves, were previously associated with low stomata conductance. Yet, very little is known about chloroplast biogenesis throughout olive leaf development. Here, the photosynthetic activity and plastids development throughout leaf maturation is characterized by biochemical and ultrastructural analyses. Although demonstrated only low photosynthetic activity, the plastids found in young leaves accumulated both photosynthetic pigments and proteins required for photophosphorylation and carbon fixation. However, Rubisco (ribulose‐1,5‐bisphosphate carboxylase–oxygenase), which catalyzes the first major step of carbon fixation and one of the most abundant proteins in plants, could not be detected in the young leaves and only slowly accumulated throughout development. In fact, Rubisco levels seemed tightly correlated with the observed photosynthetic activities. Unlike Rubisco, numerous proteins accumulated in the young olive leaves. These included the early light induced proteins, which may be required to reduce the risk of photodamage, because of light absorption by photosynthetic pigments. Also, high levels of ribosomal L11 subunit, transcription factor elF‐5A, Histones H2B and H4 were observed in the apical leaves, and in particular a plastidic‐like aldolase, which accounted for approximately 30% of the total proteins. These proteins may upregulate in their levels to accommodate the high demand for metabolic energy in the young developing plant tissue, further demonstrating the complex sink‐to‐source relationship between young and photosynthetically active mature leaves.
Biomass reallocation and the mobilization of leaf resources support dune plant growth after sand burial
Authors: Gilbert Matthew E. , Ripley Brad S.
Published: July 2008

The stimulation of dune plant growth in response to burial is a vital attribute allowing survival in areas of mobile sand. Numerous resource‐related and physiological mechanisms of growth stimulation have been suggested in the past, but few have been tested comparatively. Manipulation experiments using Scaevola plumieri, an important subtropical coastal dune forming species, demonstrated that physiological shifts were of great importance in determining the nature of the stimulation response to burial. The production of stem length and replacement of leaf area were stimulated by burial, whereas net mass production was similar between buried and unburied treatments. Remobilization of buried leaf resources, seasonal effects, and a shift in biomass allocation to stem production played the greatest role in the compensatory growth response. Other factors, such as increased soil nutrients, changes in photosynthesis, and changes in the costs of producing tissue were of less importance. Thus, the stimulated growth of species adapted to live on mobile dunes is explained by a number of resource‐related and physiological mechanisms acting in concert.
Changes in carbohydrates, ABA and bark proteins during seasonal cold acclimation and deacclimation in Hydrangea species differing in cold hardiness
Authors: Pagter Majken , Jensen Christian R. , Petersen Karen K. , Liu Fulai , Arora Rajeev
Published: July 2008

Cold injury is frequently seen in the commercially important shrub Hydrangea macrophylla but not in Hydrangea paniculata. Cold acclimation and deacclimation and associated physiological adaptations were investigated from late September 2006 to early May 2007 in stems of field‐grown H. macrophylla ssp. macrophylla (Thunb.) Ser. cv. Blaumeise and H. paniculata Sieb. cv. Kyushu. Acclimation and deacclimation appeared approximately synchronized in the two species, but they differed significantly in levels of mid‐winter cold hardiness, rates of acclimation and deacclimation and physiological traits conferring tolerance to freezing conditions. Accumulation patterns of sucrose and raffinose in stems paralleled fluctuations in cold hardiness in both species, but H. macrophylla additionally accumulated glucose and fructose during winter, indicating species‐specific differences in carbohydrate metabolism. Protein profiles differed between H. macrophylla and H. paniculata, but distinct seasonal patterns associated with winter acclimation were observed in both species. In H. paniculata concurrent increases in xylem sap abscisic acid (ABA) concentrations ([ABA]xylem) and freezing tolerance suggests an involvement of ABA in cold acclimation. In contrast, ABA from the root system was seemingly not involved in cold acclimation in H. macrophylla, suggesting that species‐specific differences in cold hardiness may be related to differences in [ABA]xylem. In both species a significant increase in stem freezing tolerance appeared long after growth ceased, suggesting that cold acclimation is more regulated by temperature than by photoperiod.
Bluffing and Waiting: Handling Effects and Post‐Release Immobility in a Death‐Feigning Snake (Natrix natrix)
Authors: Gregory Patrick T.
Published: July 2008

Tonic immobility is a common response of animals to capture by a predator; in some cases, the behaviour is elaborated into death‐feigning. Death‐feigning is usually interpreted as a last‐resort anti‐predator tactic that depends on the predator ceasing or slowing its attack when the prey is apparently dead, thus buying time for the prey to escape if the predator’s attention is directed elsewhere, even momentarily. I tested the effects of different handling regimes on the expression of death‐feigning in the grass snake (Natrix natrix). In one test, degree of handling had a significant effect on frequency of death‐feigning in small snakes, with snakes that received more handling feigning death more often. A second test showed that different initial handling regimes also affected the probability of death‐feigning in large snakes, with snakes initially held by the tail feigning death least frequently and those initially held by the head most frequently. Thus, increased apparent threat to a vulnerable part of the body is more likely to result in death‐feigning. It remains to be seen whether death‐feigning can reduce the threat posed by real predators, but immobility is frequently carried over into the post‐release period, during which the animal presumably weighs its chances and awaits an opportunity to escape. Regardless of cause, death‐feigning snakes exhibited significantly more frequent and longer post‐release immobility than did non‐death‐feigning snakes, which typically fled immediately upon release. Overall, small snakes feigned death less frequently than adults and were more likely to flee upon release, suggesting that immobility is a riskier anti‐predator defence strategy for them.
Why Do Males of the Spider Pisaura mirabilis Wrap Their Nuptial Gifts in Silk: Female Preference or Male Control?
Authors: Andersen Tina , Bollerup Kristine , Toft Søren , Bilde Trine
Published: July 2008

Males of the spider Pisaura mirabilis present a nuptial prey gift to the female during courtship as a mating effort. The gift is usually round and wrapped in white silk. It was suggested that the wrapped gift functions as a sensory trap by mimicking the female’s eggsac implying that males exploit the female maternal care instinct and not her foraging motivation in a sexual context. The shape of the gift (round) and appearance (white) should then increase female acceptance of males. We tested these predictions experimentally and found that neither gift shape (round or oblong) nor silk wrapping (wrapped or unwrapped) facilitated female acceptance, in contrast unwrapped gifts were accepted faster than wrapped ones. Instead, we found that silk wrapping benefited the males because it significantly decreased the risk of females stealing the gift without copulation and consequently directly increased male mating success. Large oblong gifts were difficult for males to handle during copulation, resulting in shorter copulations for oblong vs. round gifts. Thus, round gifts were not preferred by the females but were beneficial to the males. Our results indicate two adaptive benefits to males of wrapping the nuptial gift: to reduce the risk of losing the gift to females without copulation, and make it possible to reshape an oblong prey into a round gift that facilitates the male’s access to the female’s genitalia. Our results suggest that the male gift wrapping trait may be selected though sexual conflict over remating rate.
Use of a Magnetic Compass for Nocturnal Homing Orientation in the Palmate Newt, Lissotriton helveticus
Authors: Diego‐Rasilla Francisco J. , Luengo Rosa M. , Phillips John B.
Published: July 2008

Previous studies have shown that migrating palmate newts (Lissotriton helveticus) can rely on acoustic cues for orientation to breeding ponds. Nonetheless, although acoustic cues are reliable over relatively short distances, they are unlikely to account for the long‐distance homing demonstrated in several other species of newts. Most individuals of L. helveticus migrate only a few hundred meters (Diego‐Rasilla, F. J. & Luengo, R. M. 2007: Acoustic orientation in the palmate newt, Lissotriton helveticus. Behav. Ecol. Sociobiol. 61, 1329—1335), raising the possibility that this species may only utilize short‐distance cues (Joly, P. & Miaud, C. 1993: How does a newt find its pond? The role of chemical cues in migrating newts (Triturus alpestris). Ethol. Ecol. Evol. 5, 447—455; Russell, A. P., Bauer, A. M. & Johnson, M. K. 2005: Migration of amphibians and reptiles: an overview of patterns and orientation mechanisms in relation to life history strategies. In: Migration of Organisms (Elewa, M. T., ed). Springer‐Verlag, Berlin Heidelberg, pp. 151—203; Sinsch, U. 2006: Orientation and navigation in Amphibia. Mar. Freshw. Behav. Phy. 39, 65—71). Therefore, experiments were carried out to investigate the use of the geomagnetic field in the nocturnal homing orientation of L. helveticus. Tests were carried out at night in an outdoor circular arena, under total overcast sky that prevented access to celestial compass cues. Individual newts were tested in one of four symmetrical alignments of an earth‐strength magnetic field. We studied the orientation behaviour of newts from two breeding ponds located 9.05 km west‐southwest and 19 km east‐northeast of the testing site. The distribution of magnetic bearings from both groups of newts exhibited significant orientation in the homeward direction. These findings indicate that palmate newts are capable of long‐distance homing and are able to orient in the homeward direction at night using the magnetic compass as the sole source of directional (i.e., compass) information.
High Temperature‐induced Changes in High Molecular Weight Glutenin Subunits of Chinese Winter Wheat and its Influences on the Texture of Chinese Noodles
Authors: Deng Z. , Tian J. , Zhao L. , Zhang Y. , Sun C.
Published: July 2008

Post‐anthesis temperature affects wheat flour quality, dough properties and end‐use quality. In order to investigate the changes in high molecular weight glutenin subunit (HMW‐GS) expression caused by elevated temperature and its influences on the texture properties of Chinese noodles, three temperature‐induced (<35 °C) treatments were applied to two cultivars with different gluten strengths. The cultivars were grown outside in 0.75 m2 containers on the farm of Shandong Agricultural University in 2003–2004. Three post‐anthesis temperature treatments, at 15 days after anthesis (DAA), 20 and 25 DAA, respectively, were applied during the grain‐filling period by moving the containers from outside into a greenhouse at three replicates per treatment. At maturity, the HMW‐GS was extracted. The results indicated that the HMW‐GS expression from the wheat with stronger gluten strength appeared to be more tolerant under the different treatments than did that from the weaker dough strength wheat. The same HMW‐GS (5 + 10) from different cultivars showed different effects on noodle quality. Moderately high temperature treatments benefited wet noodle texture quality and noodle scores at a different degree. All HMW‐GS expression in wheat with the weaker strength appeared to be negatively correlated with wet noodle firmness (WNF) and wet noodle cutting force (WNCF). Some correlation coefficients showed significance. However, HMW‐GS expression at Glu‐B1 and individual Glu‐B1x14 expression from the strong wheat demonstrated significantly positive correlations with WNF and WNCF. Individual HMW‐GS expression of the Glu‐B1 and Glu‐B1 location and the X‐type subunits showed significantly positive correlations with the noodle score. The same HMW‐GS at Glu‐D1 from varieties with different gluten strength had different contributions to noodle quality.
Sex pheromone of Ostrinia sp. newly found on the leopard plant Farfugium japonicum
Authors: Tabata J. , Huang Y. , Ohno S. , Yoshiyasu Y. , Sugie H. , Tatsuki S. , Ishikawa Y.
Published: July 2008

Recently, larvae of Ostrinia were found feeding on the leopard plant Farfugium japonicum (Asteraceae), previously unrecorded as a host plant of this genus. The adult moths that developed from these borers were morphologically similar to, but distinct from, Ostrinia zaguliaevi, a monophagous species specialized for feeding on another Asteraceae plant, the butterbur Petasites japonicus. Although the taxonomical status of the moth feeding on F. japonicum is to be determined, distinct morphological differences in the adults strongly suggest this to be a new species (hereafter referred to as O. sp.). To gain an insight into the reproductive isolation between O. sp. and other members of the genus Ostrinia, the female sex pheromone and the males’ response to it were investigated using samples collected from F. japonicum. (Z)‐9‐tetradecenyl acetate (Z9‐14:OAc), (Z)‐11‐tetradecenyl acetate (Z11‐14:OAc), (E)‐11‐tetradecenyl acetate (E11‐14:OAc), tetradecyl acetate, and (Z)‐11‐hexadecenyl acetate were identified as candidates for sex pheromone components by analyses using gas chromatographs coupled to a mass spectrometer (GC‐MS) and electroantennographic detector (GC‐EAD). A series of bioassays of male responses in a wind‐tunnel and a field cage indicated that the former three compounds are essential for attracting males, and the latter two have no synergistic effect on the attraction. We therefore concluded that Z9‐14:OAc, Z11‐14:OAc and E11‐14:OAc are the sex pheromone components of O. sp. Although the same three compounds are used as the sex pheromone components of O. zaguliaevi and another congener, Ostrinia zealis, the blend proportions differed greatly among the three (Z9‐14:OAc/Z11‐14:OAc/E11‐14:OAc = 18/76/6 in O. sp., 45/50/5 in O. zaguliaevi and 70/6/24 in O. zealis). Differences in sex pheromones could contribute to the reproductive isolation between O. sp. and the other two Ostrinia species if males of each species exhibit a narrow window of response to their own blend ratio.
The Manipulation of Gametes and Embryos in Farm Animals
Authors: Galli C , Lazzari G
Published: July 2008

Contents

This paper summarizes the major advances in farm animal assisted reproduction in the last 20 years with particular attention to the contributions of the authors. A main emphasis is on the biology of the oocyte, including a description of methods for isolation of developing follicles and culture of the corresponding oocytes. Milestones that have led to optimization of procedures for maturation of fully grown oocytes, fertilization, intracytoplasmic sperm injection and embryo culture in sheep, cattle, pigs and horses are described. The current status of nuclear transfer, cloning and embryonic stem cell generation and culture is also summarized for all major farm animal species. It is concluded that the manipulation of early development in farm animals is of crucial importance for agricultural purposes and that reproductive biotechnologies in farm animals are expected to play an increasing role in the next decades due to the growing demand for agricultural products from the emerging economies worldwide. In the biomedical field large animals represent increasingly important research models especially in the stem cell field for creating genetically modified animals for specific purposes. Finally, the successful translation of large animal research in the applied context requires solid science, long‐term resource commitment from involved institutions, and vision, dedication and entrepreneurial skills from the scientists involved.
Endocrine Disruptors and Other Food‐contaminating Environmental Pollutants as Risk Factors in Animal Reproduction
Authors: Rhind SM
Published: July 2008

Contents

Pollutants of many chemical classes, derived primarily from anthropogenic activities, are ubiquitous in the environment, persistent, biologically available and can exert adverse effects on the reproductive and other, indirectly related, physiological systems. Food is generally considered to be the major route of animal exposure in vertebrate species but the relative contributions of other routes of exposure such as through lungs, gills or skin are not well studied and may be of importance for certain animal groups, depending on their immediate environment. Animals are particularly sensitive to exposure during developmental stages but the pattern of exposure to chemicals is likely to be different to that of adults. Quantification of the risk posed by the ingestion of pollutants in food is complex and depends on many factors including species, diet composition, duration of exposure to the food, efficiency of pollutant absorption, subsequent metabolism, sensitivity of target organs and stage of development. While the effects of high doses of single chemicals are proven, dietary exposure to pollutants generally involves prolonged, low‐level exposure to a large number of compounds, each of which has different chemical characteristics, exerts different biological effects and is present at varying concentrations. Thus, while exposure to pollutants through feed is undoubtedly a significant risk factor for many species and may be the most important one for many terrestrial vertebrates, other routes of exposure may be more important in other groups.
Long Chain Fatty Acids of Diet as Factors Influencing Reproduction in Cattle
Authors: Santos JEP , Bilby TR , Thatcher WW , Staples CR , Silvestre FT
Published: July 2008

Contents

Cattle are fed moderate amounts of long chain fatty acids (FA) with the objective to enhance lactation and growth; however, recent interest on lipid feeding to cows has focused on reproduction, immunity and health. Increasing the caloric density of the ration by fat feeding has generally improved measures of cow reproduction, but when milk yield and body weight losses were increased by fat supplementation, positive effects on reproduction were not always observed. Feeding fat has influenced reproduction by altering the size of the dominant follicle, hastening the interval to first postpartum ovulation in beef cows, increasing progesterone concentrations during the luteal phase of the oestrous cycle, modulating uterine prostaglandin (PG) synthesis, and improving oocyte and embryo quality and developmental competence. Some of these effects were altered by the type of FA fed. The polyunsaturated FA of the n‐6 and n‐3 families seem to have the most remarkable effects on reproductive responses of cattle, but it is not completely clear whether these effects are mediated only by them or by other potential intermediates produced during rumen biohydrogenation. Generally, feeding fat sources rich in n‐6 FA during late gestation and early lactation enhanced follicle growth, uterine PG secretion, embryo quality and pregnancy in cows. Similarly, feeding n‐3 FA during lactation suppressed uterine PG release, and improved embryo quality and maintenance of pregnancy. Future research ought to focus on methods to improve the delivery of specific FA and adequately powered studies should be designed to critically evaluate their effects on establishment and maintenance of pregnancy in cattle.
Reproductive Biotechnology and Gene Mapping: Tools for Conserving Rare Breeds of Livestock
Authors: Long JA
Published: July 2008

Contents

Today’s livestock diversity originated from the wild ancestor species and was subsequently shaped through the processes of mutation, genetic drift, and natural and human selection. Only a subset of the diversity present in the ancestral species survives in the domestic counterparts. A 2007 report released by UN Food and Agriculture Organization ‘The State of the World’s Animal Genetic Resources’, compiled from surveys conducted in 169 countries, found that nearly 70% of the world’s remaining livestock breeds live in developing countries. The UN report was presented to more than 300 policy makers, scientists, breeders, and livestock keepers at the First International Technical Conference on Animal Genetic Resources, held in September 2007 in Interlaken, Switzerland. The conference aims were to adopt a global plan of action for conserving animal genetic resources as its main outcome. In this paper, the current and potential contributions of reproductive and molecular biotechnology are considered as tools of conserving rare breeds of livestock.
Genetic Improvement of Dairy Cow Reproductive Performance
Authors: Berglund B
Published: July 2008

Contents

The welfare of cow along with profitability in production are important issues in sustainable animal breeding programmes. Along with an intense/intensive selection for increased milk yield, reproductive performance has declined in many countries, in part due to an unfavourable genetic relationship. The largely unchanged genetic trend in female fertility and calving traits for Scandinavian Red breeds shows that it is possible to avoid deterioration in these traits if they are properly considered in the breeding programme. Today’s breeding is international with a global selection and extensive use of the best bulls. The Nordic countries have traditionally recorded and performed genetic evaluation for a broad range of functional traits including reproduction. In recent years many other countries have also implemented genetic evaluation for these traits. Thus, the relative emphasis of dairy cattle breeding objectives has gradually shifted from production to functional traits such as reproduction. Improved ways of recording traits, e.g. physiological measures, early indicator traits, assisted reproductive techniques and increased knowledge of genes and their regulation may improve the genetic selection strategies and have large impact on present and future genetic evaluation programmes. Extensive data bases with phenotypic recordings of traits for individuals and their pedigree are a prerequisite. Quantitative trait loci have been associated to the reproductive complex. Most important traits, including reproduction traits are regulated by a multitude of genes and environmental factors in a complex relationship, however. Genomic selection might therefore be important in future breeding programmes. Information on single nucleotide polymorphism has already been introduced in the selection programmes of some countries.
Nutrient Prioritization in Dairy Cows Early Postpartum: Mismatch Between Metabolism and Fertility?
Authors: Leroy JLMR , Vanholder T , Van Knegsel ATM , Garcia‐Ispierto I , Bols PEJ
Published: July 2008

Contents

For several decades, researchers worldwide report a decrease in fertility in high‐yielding dairy cows, most probably based on conflicting metabolic and reproductive needs. The dairy herd manager’s success at improving milk production has been accompanied by a negative trend for the most visible reproductive parameters such as calving intervals, number of days open and number of inseminations needed per pregnancy. In parallel, many research groups studied the metabolic and endocrine factors that influence follicular growth and the developmental competence of oocytes and embryos. In the past, herd managers and reproductive biologists each tried to tackle the same problems with limited consultation. More recently, the situation has improved significantly and theriogenologists, nutritionists and veterinarians now conduct research in multidisciplinary teams. This review paper starts in a general way by discussing nutrient prioritization towards the udder to guarantee milk production and by describing interactions between the somatotropic and gonadotropic axis. It then focuses on the consequences of the negative energy balance on follicular growth and environment, oocyte and embryo quality, not only by summarizing the currently accepted hypotheses but also based on clear scientific evidence at the follicular level. All this, with one question in mind: is there a mismatch between metabolism and fertility and what can the dairy manager learn from research to tackle the problem of reduced fertility?
Corpus Luteum–Endometrium–Embryo Interactions in the Dairy Cow: Underlying Mechanisms and Clinical Relevance
Authors: Robinson RS , Hammond AJ , Wathes DC , Hunter MG , Mann GE
Published: July 2008

Contents

Conception rates of dairy cows are currently declining at an estimated 1% every year. Approximately, 35% of embryos fail to prevent luteolysis during the first three weeks of gestation. Interactions between the corpus luteum, endometrium and embryo are critical to the successful establishment of pregnancy and inadequacies will result in the mortality of the embryo. For example, as little as a one day delay in the post‐ovulatory rise of progesterone has serious consequences for embryo development and survival. Recently, we found that LH support, degree of vascularization and luteal cell steroidogenic capacity were not the major factors responsible for this luteal inadequacy, but are nevertheless essential for luteal development and function. Progesterone acting on its receptor in the endometrium stimulates the production of endometrial secretions on which the free‐living embryo is dependent. However, their exact composition and effects of inadequate progesterone remains to be determined. The embryo is recognized through its secretion of interferon tau (IFNT), which suppresses luteolytic pulses of prostaglandin F2α. In the cow, it is most likely that IFNT inhibits oxytocin receptor up‐regulation directly and does not require the prior inhibition of oestrogen receptor α (ESR1). Unravelling the precise luteal‐endometrium and embryo interactions is essential for us to understand pregnancy establishment and development of strategies to reverse the declining fertility of dairy cows.
The Importance of Interactions Among Nutrition, Seasonality and Socio‐sexual Factors in the Development of Hormone‐free Methods for Controlling Fertility
Authors: Scaramuzzi RJ , Martin GB
Published: July 2008

Contents

Around the world, consumers are demanding animal products that are produced to agreed standards for human health, environmental management and animal welfare. This has led to the development in Australia of the concept of ‘clean, green and ethical’ (CGE) animal production based on the manipulation of nutrition (‘focus feeding’) and the application of phenomena, such as the ‘male effect’, to provide ‘natural’ methods for managing small ruminant production systems. With respect to the management of fertility, CGE involves utilization of the inherited responses of animals to environmental factors to manipulate their reproductive processes. The successful development and implementation of this new generation of management tools depends on a thorough yet holistic understanding of the interactions among environmental factors and the ways these interactions affect reproductive physiology and behaviour of the animal. For sheep and goats, a central aspect of CGE management is the way in which ovarian function is affected by three major factors (nutrition, photoperiod and socio‐sexual signals) and by interactions among them. Nutrition can exert two profound yet contrasting types of effect on ovarian activity: (i) the complete inhibition of reproduction by undernutrition through the hypothalamic mechanism that controls ovulation and (ii) the enhancement of fecundity by nutritional supplementation, through a direct ovarian mechanism, in females that are already ovulating. A similarly profound control over ovarian function in female sheep and goats is exerted by the well‐known endocrine responses to photoperiod (seasonality) and to male socio‐sexual signals. The ‘male effect’ already has a long history as a valuable technique for inducing a synchronized fertile ovulation during seasonal and post‐partum anoestrus in sheep and goats. Importantly, experimentation has shown that these three major environmental factors interact, synergistically and antagonistically, but the precise nature of these interactions and their significance to reproductive outcomes are not well understood. Most research to date has been with small ruminants but CGE principles can be applied to any species in a managed environment. For example, a male effect has been reported for lactating cattle and, in the horse, the pattern of seasonality of oestrus can be altered by nutrition. Well‐fed mares have a longer breeding season and some animals become non‐seasonal. Similar observations have been reported for sheep and goats. By working towards a holistic perspective of the physiology, nutrition, genetics and behaviour of our animals, we will be able to formulate ways to manipulate the animals’ environment that will improve management, productivity and profitability and, simultaneously, promote a CGE industry.
Developmental Capabilities of Embryos Produced In Vitro from Prepubertal Lamb Oocytes
Authors: Morton KM
Published: July 2008

Contents

Breeding from prepubertal females, known as juvenile in vitro embryo transfer (JIVET), reduces the generation interval and increases the rate of genetic gain in animal breeding programs. While the birth of the first lambs from prepubertal ewes occurred nearly 30 years ago; and there is considerable interest in the commercialization of this technology, its efficiency remains too low. The advent of in vitro production (IVP) of embryo resulted in the more widespread use of JIVET. Morphologic and metabolic differences coupled with reduced in vitro and in vivo development of oocytes derived from prepubertal animals have been reported. Research has been undertaken to optimize donor selection and hormone stimulation methods in an attempt to reduce the variability and increase the proportion of donors responding to hormone stimulation and increase oocyte developmental competence. Yet, this variation persists and the development of oocytes and embryos from prepubertal animals remains reduced when compared with adults. Recent improvements to JIVET, resulting from a modified hormone stimulation regime, have eliminated the failure of donors to respond to hormone stimulation, and increased both the number and developmental competence of oocytes harvested from very young prepubertal lambs. This increased efficiency has facilitated the incorporation of other reproductive technologies such as sperm sexing with JIVET, resulting in the birth of lambs of a pre‐determined sex from prepubertal lambs. Increased rates of genetic gain in sheep breeding programs can be achieved by combining sexed sperm with oocytes obtained from lambs as young as 3–4 weeks of age. Continued increases in the efficiency of JIVET resulting from further improvements to hormone stimulation regimes and an increased understanding of the differences between oocytes from adult and prepubertal animals will result in the commercialization of this technology.
The Ethics and Role of AI with Fresh and Frozen Semen in Dogs
Authors: England GCW , Millar KM
Published: July 2008

Contents

The use of artificial insemination (AI) with fresh semen has resulted in many benefits for the management of dog breeding, but there are disadvantages that can sometimes be overlooked. Furthermore, poorer quality semen arising as a result of cryopreservation necessitates uterine insemination, which raises the potential for surgical insemination. A number of significant ethical concerns have been raised by key stakeholders (such as The Kennel Club and the Royal College of Veterinary Surgeons) about AI per se, but particularly about the use of surgical insemination. This paper discusses the technological development of AI and explores a number of the ethical issues raised by its application to dog breeding. An Ethical Matrix method is used to map the potential ethical issues for key interest groups, namely dogs, breeders, owners, veterinarians and wider society. There are national variations in the way in which institutions have evaluated potential ethical impacts, and this is reflected in the different regulatory frameworks governing the use of AI in dogs. In order to facilitate decision‐making and reduce some of the ethical risks associated with this technology, the veterinary research community could take several proactive steps including: (i) clarifying clinical decision‐making processes, (ii) enhancing informed choice among clients and (iii) increasing the knowledge‐base of potential impacts of AI.
Controlling Animal Populations Using Anti‐Fertility Vaccines
Authors: Fayrer‐Hosken R
Published: July 2008

Contents

The goal for fertility control of animal populations is the development of a safe, economical and effective contraceptive. One offshoot of the development of this technology is the acquisition of multiple therapeutic strategies for diseases, such as immunotherapy probes for cancer. In the long run, successful population control requires multifactorial strategies. One component of population control is immunocontraception. Development of effective antigens for immunocontraceptive vaccines has been remarkable and has greatly advanced our understanding of the molecular mechanisms of fertilization. The chasm between the discovery of an antigen in the laboratory, to the implementation of an effective field program, is immense. The zona pellucida (ZP) immunocontraceptive that has been most extensively evaluated as a fertility vaccine antigen and the porcine ZP has received particular attention. The long‐term goal of population control would be the use of a synthetic vaccine, e.g. the ZP, tailored to a target species. In the future, if populations’ levels are to be controlled by fertility vaccines, we should consider that the vaccinated animals could receive other health protective agents at the same time. For example, if a species were immunocontracepted, then they could be simultaneously vaccinated against habitat diseases such as rabies (Plumb et al., Rev Sci Tech, 26, 2007, 229).
Recent Progress in Embryonic Stem Cell Research and Its Application in Domestic Species
Authors: Brevini TAL , Antonini S , Pennarossa G , Gandolfi F
Published: July 2008

Contents

Many reports described cell lines derived in domestic species, which presented several important features typical of embryonic stem cells (ESCs). Such features unfortunately did not include the capacity to generate germ‐line chimeras, therefore limiting the possibility to use these cells as tools for the genetic manipulation. However, farm animal ESCs may still be useful for the generation of transgenic animals as usually have a self‐renewal capacity more prolonged than normal primary cultures thus increasing the possibility to transform and select cells to be used as nucleus donors in cloning procedures. Farm animal ESCs may also be an excellent experimental model in pre‐clinical trials, assessing the feasibility of cell therapy because of the close morphological and physiological resemblance to humans of species like the pig. However, the persistent lack of standard methods for the derivation, maintenance and characterization of ESCs in domestic species stimulated the search for alternatives. Embryonic germ cells may represent such an alternative. Indeed, these cells showed a higher plasticity than ESCs as contributed to embryonic development forming chimeric newborns but, as for ESCs, standardization is still far away and efficiency is very low. Recent results indicated spermatogonial stem cells as possible tools for germ‐line genetic modifications with some proof of principle results already achieved. But, a real break through could arrive from the multipotent germ‐line stem cells, virtually equivalent to ESC, derived from newborn and adult mouse testis.
Reproduction in Domestic Buffalo
Authors: Perera BMAO
Published: July 2008

Contents

The domestic buffalo is an indispensable livestock resource to millions of smallholder farmers in developing countries, particularly in Asia. Although its reproductive biology is basically similar to that of cattle, there are important differences and unique characteristics that need to be considered in order to apply modern reproductive technologies to improve its productivity. Under most smallholder production systems, the reproductive efficiency of buffalo is compromised by factors related to climate, management, nutrition and diseases. However, when managed and fed properly, buffalo can have good fertility and provide milk, calves and draught power over a long productive life. The basic technical problems associated with artificial insemination in buffalo were largely overcome two decades ago, but the technology has not had the expected impact in some developing countries, because largely of infrastructural and logistic problems. Approaches involving the use of hormones for treating anoestrus and for synchronizing oestrus have had varying rates of success, depending on the protocols used and the incidence of underlying problems that cause infertility. Embryo technologies such as multiple ovulation embryo transfer, in vitro embryo production, cryopreservation and cloning are being intensively studied but have had far lower success rates than in cattle. Improving the productivity of buffalo requires an understanding of their potential and limitations under each farming system, development of simple intervention strategies to ameliorate deficiencies in management, nutrition and healthcare, followed by judicious application of reproductive technologies that are sustainable with the resources available to buffalo farmers.
Mother–Offspring Interactions in Zebu Cattle
Authors: Paranhos da Costa MJR , Schmidek A , Toledo LM
Published: July 2008

Contents

The knowledge of the interaction between mother and offspring might contribute to enhance the welfare of the offspring and to improve the reproductive efficiency of the cow. However, there is still little information available about such interaction in some cattle breeds. A series of observational studies were set up, addressing the mother–offspring relationships of Nelore, Guzerat and Gyr cattle breeds. Firstly, the behaviour of cows and calves around the time of parturition was described, and then, the underlying factors that affect the calves’ survival and development were studied. Special attention was given to the failure or delay in the first suckling. The results together are indicative of genetic variability for some studied variables, indicating the possibility of selection for calf vigour (using latency to stand up and latency to suckle as its indicators) and maternal ability (using percentage of time in contact with the calves), in spite of the estimates of heritability were low and presented high standard deviation for all variables. The individual variability in their suckling behaviour and the efficiency in first suckling cannot be explained by a single isolated underlying factor. By now, there are some results available, although there are many questions without answers. The field is still open for the development of future research.
An Update on Reproduction in Yak and Mithun
Authors: Prakash BS , Sarkar M , Mondal M
Published: July 2008

Contents

Yak and mithun are two domesticated herbivores of high economic importance to the farming community living in highlands. Improved yak and mithun production could significantly enhance the living standards of these highlanders. Over the years, their dwindling numbers have been a cause of serious concern. In view of the lack of knowledge on the reproductive physiology of these ruminants, studies have been undertaken to investigate their reproductive endocrinology in recent years. This paper attempts to present the latest information on the endocrine changes associated with their various reproductive processes viz. growth and puberty, oestrous cyclicity and oestrous behaviour, ovulation, and, pregnancy and parturition. The paper also provides the recent developments on research done towards the enhancement of yak and mithun reproductive efficiencies through endocrine and embryo biotechniques.
Proteins Associated With the Early Intrauterine Equine Conceptus
Authors: Hayes MA , Quinn BA , Keirstead ND , Katavolos P , Waelchli RO , Betteridge KJ
Published: July 2008

Contents

A critical period of early gestation in the mare involves the immobilization (fixation) of the encapsulated conceptus at around days 16–17. We compared the major proteins in the normal equine embryonic capsule and endometrial secretions around the period of fixation with those from pregnancies in the process of termination induced by administration of an analogue of prostaglandin F2α(PGF2α). Uterocalin and β2‐microglobulin (β2M) associated with the embryonic capsule were proteolytically converted to smaller forms during the fixation period. These conversions were similar in conceptuses from control and treated mares. A 17 kDa cationic protein identified as a secretory phospholipase A2 (sPLA2) type IIA was detected bound to normal capsules but increased substantially in response to PGF2α. Two forms of uteroglobin were distinguished by partial amino acid sequences of ∼6 kDa bands in flush fluids from normal pregnant uteri. After administration of PGF2αone immunoreactive form of uteroglobin was preferentially increased. These studies demonstrate that failure of pregnancy in this model is associated with an increase in secretory phospholipase in the capsule and a change in the forms of uteroglobin in the uterine secretions.
Heat Stress, the Follicle, and Its Enclosed Oocyte: Mechanisms and Potential Strategies to Improve Fertility in Dairy Cows
Authors: Roth Z
Published: July 2008

Contents

Reduced reproductive performance of lactating cows during the summer is associated with decreased thermoregulatory competence due to intensive genetic selection for high milk production. This review examines the immediate and delayed effects of heat stress on follicular function and describes some potential strategies for their alleviation. It focuses on how heat stress affects the follicle and its enclosed oocyte, suggesting that perturbations in the follicular microenvironment, to which the oocytes are exposed for long periods of development, reduce their developmental competence. Among the potential alterations are reduction in gonadotropin secretion, alteration in follicular growth, attenuation of dominance, and disruption of steroidogenesis. Evaporative cooling methods are the most common strategy used to alleviate the effect of heat stress; however, there is a compelling need to find additional ways to improve fertility during the summer and autumn. Hormonal treatment to enhance removal of the impaired follicles by synchronization of follicular waves with GnRH and PGF2α is suggested. An alternative method is stimulation of follicular growth by a brief treatment with bST or FSH. Other strategies, such as timed AI and embryo transfer, have been recently used, making the optimization of embryo cryopreservation procedures highly relevant. Protection of the ovarian pool of oocytes from thermal stress via nutritional manipulations or administration of antioxidants or other survival factors should also be considered. A better understanding of the underlying mechanisms by which heat stress impairs fertility may lead to the development of additional approaches to alleviate these effects.
Fertilization and Early Embryonic Development in the Porcine Fallopian Tube
Authors: Brüssow K‐P , Rátky J , Rodriguez‐Martinez H
Published: July 2008

Contents

Fertilization and early embryo development relies on a complex interplay between the Fallopian tube and the gametes before and after fertilization. Thereby the oviduct, as a dynamic reproductive organ, enables reception, transport and maturation of male and female gametes, their fusion, and supports early embryo development. This paper reviews current knowledge regarding physiological processes behind the transport of boar spermatozoa, their storage in and release from the functional sperm reservoir (SR), and of the interactions that newly ovulated oocytes play within the tube during their transport to the site of fertilization. Experimental evidence of an ovarian control on sperm release from the SR is highlighted. Furthermore, the impact of oviductal secretion on sperm capacitation, oocyte maturation, fertilization and early embryo development is stressed.