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PubMed2004

Time of farmers' exposure to biological factors in agricultural working environment.

Working time in conditions of exposure to hazardous factors is an important element indispensable for the evaluation of human exposure in the working environment. Agricultural work is accompanied by co-occurrence of many risk factors threatening farmers' health, e.g. dust, elements of the thermal environment, noise, vibration, chemical and biological agents. Biological factors cause diseases with contagious, allergic or immuno-toxic backgrounds which constitute the majority of farmers' occupational diseases registered in Poland. Exposure to hazardous factors in agricultural working environment is due to contact with plants, animals and organic wastes, more precisely--with microbes, plant and animal particles present in aerogenic agricultural dust, as well as pathogens of contagious and invasive diseases present in contaminated soil, water and plants. Data concerning the duration of farmers' exposure to biological and other factors of the working environment were obtained with the use of the Private Farmer Work Chart. Time-schedule observations concerned an annual work cycle. The study covered 30 farms with the following production profiles: plant (Group A), animal (Group B) and mixed production (Group C). The total working time was: in Group A - from 106-163 % of the legal working time; in Group B - from 75-147 %; in Group C - from 136-167 %. Among 48 work activities contributing to the full working cycle among the farmers examined, 15 activities were accompanied by 5 factors. These were mainly field activities which covered plant harvesting and fertilizing, chemical plant protection, as well as cultivation activities. Agricultural dust and elements of the thermal environment were the environmental factors most frequently accompanying agricultural work, followed by contact with biological factors, noise, vibration, and chemical agents. Biological factors are a specific element associated with 19 work activities, mainly the spreading of manure, animal breeding and plant harvesting. Farmers' working time in conditions of exposure to these factors in the group of plant producers was 51 % of the total working time on average, among animal breeders--80 % and in the case of mixed production--77 %.

Adult↗
PubMed1979

A mutant of Tetrahymena thermophila with a partial mirror-image duplication of cell surface pattern. II. Nature of genic control.

The CU-127 clone of Tetrahymena thermophila, which manifests an unusually high number of ciliary rows plus a second set of abnormal oral structures and of contractile vacuole pores with partial mirror-image reversal of asymmetry (Jerka-Dziadosz & Frankel, 1979), has been subjected to breeding analysis. The progeny ratios obtained in various crosses indicate that the abnormalities of cell-surface asymmetry are brought to expression as a result of the action of a recessive allele at a single gene locus, here named janus. When previously normal cells were made homozygous for the jan allele, the cortical pattern characteristic of the CU-127 clone came rapidly to expression, often without associated change in number of ciliary meridians. Conversely, when cells previously expressing jan re-acquired the wild-type (jan+) allele, they returned to the normal pattern of a single normal oral structure and a single normally located set of contractile vacuole pores while still retaining the high ciliary meridian number characteristic of the original CU-127 clone. The capacity for manifestation of the unique asymmetry pattern depends solely on homozygous expression of the janus allele, whereas the stable number of ciliary meridians in janus clones and the degree of expression of secondary OAs is modulated by other factors, probably at least in part genic. These results, taken together with those of the preceding paper, indicate that the janus allele promotes the propagation and/or expression of a condition of reversed asymmetry in a precisely located cell region, and further indicates that the propagation and expression of this condition are largely independent of the number and asymmetry of ciliary meridians.

Alleles↗
PubMed2004

The scurs locus in cattle maps to bovine chromosome 19.

Polled, or the absence of horns, is a desirable trait for many cattle breeders. However, the presence of scurs, which are small horn-like structures that are not attached to the skull, can lower the value of an animal. The scurs trait has been reported as sex influenced. Using a genome scan with 162 autosomal microsatellite markers genotyped across three full-sib families, the scurs locus was mapped near BMS2142 on cattle chromosome 19 (LOD = 4.21). To more precisely map scurs, the families from the initial analysis and three additional families were genotyped for 16 microsatellite markers and SNPs in three genes on chromosome 19. In this subsequent analysis, the scurs locus was mapped 4 cM distal of BMS2142 (LOD = 4.46) and 6 cM proximal to IDVGA46 (LOD = 2.56). ALOX12 and MFAP4 were the closest genes proximal and distal, respectively, to the scurs locus. Three microsatellite markers on the X chromosome were genotyped across these six families but were not linked to scurs, further demonstrating that this trait was not sex linked. Because the polled locus has been mapped to the centromeric end of chromosome 1 and scurs has now been mapped to chromosome 19, these two traits are not linked in Bos taurus.

Agriculture↗
PubMed2001

A review of canine pseudocyesis.

The purpose of this article is to review the most relevant features of the physiology, clinical signs, diagnosis, treatment and prevention of canine pseudocyesis (PSC). This is a physiological syndrome, characterized by clinical signs such as: nesting, weight gain, mammary enlargement, lactation and maternal behaviour, which appears in non-pregnant bitches at the end of metaoestrus. PSC is a frequent finding in domestic dogs. Although it is generally admitted that prolactin (PRL) plays a central role in the appearance of PSC, its precise aetiophysiology is not completely understood yet. A number of clinical studies suggest that at some point of metaoestrus circulating PRL levels rise in overtly pseudopregnant bitches. Individual differences in sensitivity to PRL as well as the existence of molecular variants of canine PRL with different bioactivity versus immunoreactivity ratios may help clarify the aetiopathology of PSC. Diagnosis of PSC is based on the presence of typical clinical signs in metaoestrous non-pregnant bitches. Considering that PSC is a self limiting physiological state, mild cases usually need no treatment. Discouraging maternal behaviour and sometimes fitting Elizabethan collars to prevent licking of the mammary glands may suffice in these cases. Sex steroids (oestrogens, progestins and androgens) have been traditionally used to treat PSC but the side-effects usually outweigh the benefits of these medications. Inhibition of PRL release by ergot derivatives [bromocriptine (10-100 microg/kg per day for 10-14 days], cabergoline (5 microg/kg per day during 5-10 days), metergoline (0.2 mg/kg per day during 8-10 days) has proved to be effective for the treatment of canine PSC. Although some of these ergot derivatives present some untoward side-effects, they are transient and can usually be managed. Predisposed bitches not intended for breeding should be spayed as ovariectomy is the only permanent preventive measure.

Animals↗
PubMed1992

Detection of minimal residual disease in acute leukemia by immunological marker analysis and polymerase chain reaction.

Detection of minimal residual disease (MRD) can be useful for adaptation or stratification of treatment in acute leukemia patients and may finally result in individualization of treatment protocols. Although leukemic cells generally have immunophenotypes comparable to their normal counterparts, it is possible to use immunological marker analysis for the detection of MRD based on the assumption that the presence of positive cells outside their normal breeding sites and 'homing areas' is indicative of malignancy. This approach can be used for the detection of MRD in blood and bone marrow of patients with a terminal deoxynucleotidyl transferase (TdT) positive T-cell acute lymphoblastic leukemia (ALL) and patients with a TdT+ acute myeloid leukemia (AML) as well as in cerebrospinal fluid of patients with a TdT+ leukemia. In other types of acute leukemias, immunological marker analysis generally does not allow detection of low frequencies of malignant cells, but in a part of them the polymerase chain reaction (PCR) technique may be valuable. The PCR technique allows the amplification of tumor-specific DNA sequences or mRNA sequences (after reverse transcription into cDNA), if the flanking sequences are well-defined. This PCR-mediated amplification can detect specific sequences which are derived from only a few malignant cells between many normal cells. Well-defined chromosome translocations have been used as tumor-specific markers, such as t(9;22). An advantage of using specific chromosome aberrations as tumor-specific markers is their stability during the disease course. However, only 10-15% of ALL and 25-30% of AML have a specific chromosome translocation and in a large part of them the precise breakpoints are not (yet) known. Recent studies indicate that it is possible to detect MRD in acute leukemias by use of PCR-mediated amplification of the junctional regions of rearranged immunoglobulin (Ig) and T-cell receptor (TcR) genes, using variable (V) and joining (J) gene-specific oligonucleotides as primers. Major pitfalls of this application are the occurrence of multiple rearrangements at diagnosis (oligoclonality) and changes in rearrangement patterns at relapse (clonal evolution), which will lead to false negative results of this MRD-PCR technique. In conclusion, the technique of choice for the detection of MRD is dependent on the immunophenotype of the leukemia, the presence of a well-defined chromosome translocation and the presence of a rearranged Ig and/or TcR gene as well as the chance of immunophenotypic shifts and changes in Ig and TcR gene rearrangement patterns.(ABSTRACT TRUNCATED AT 400 WORDS)

Acute Disease↗
PubMed2005

Interseasonal variation in blood concentrations of organochlorines in great black-backed gulls (Larus marinus).

In two subsequent breeding seasons (2001 and 2002), we measured 12 organochlorines (OCs), including hexachlorobenzene (HCB), beta-hexachlorocyclohexane (beta-HCH), p,p'-dichlorodiphenyldichloroethylene (DDE), oxychlordane, and eight polychlorinated biphenyl congeners (PCBs), in the blood of the same 25 great black-backed gulls (Larus marinus). The wet-weight concentrations of different OCs in the blood decreased between 45 and 60% from 2001 to 2002. The main reasons for this were lower blood-lipid concentrations and higher body condition in 2002 compared to 2001. The differences in blood lipids and body condition probably resulted from changes in the availability of different prey types between the years. Despite the variation in the blood concentrations of OCs, there was a high predictability of the relative relationship among individuals between the years, especially for the most-persistent compounds (persistent PCBs, oxychlordane, and DDE); that is, individuals with high levels in 2001 still had relatively high levels compared to other individuals in 2002. This suggests that a concentration obtained from a single blood sample is a relatively reliable measurement of OC burdens for individual great black-backed gulls compared to other individuals, independent of changes in mean OC levels within the population. However, by including information about the nutritional status of individuals, more precise interference from samples in different years and locations may be made. Moreover, the great seasonal variation in OC levels within individuals may have implications for how OC monitoring should be conducted in gull populations.

Animals↗
PubMed2004

Natural methods for increasing reproductive efficiency in small ruminants.

This paper describes three strategies to improve the reproductive performance of small ruminants in ways that lead to "clean, green and ethical" animal production. The first is aimed at control of the timing of reproductive events for which we turn to the socio-sexual inputs of the "male effect" to induce synchronised ovulation in females that would otherwise be anovulatory. The second strategy, "focussed feeding", is based on our knowledge of the responses to nutrition and aims to develop short programs of nutritional supplements that are precisely timed and specifically designed for individual events in the reproductive process, such as gamete production, embryo survival, fetal programming and colostrum production. The third strategy aims to maximise offspring survival by a combination of management, nutrition and genetic selection for behavior (temperament). All of these approaches involve non-pharmacological manipulation of the endogenous control systems of the animals and complement the detailed information from ultrasound that is now becoming available. The use of such clean, green and ethical tools in the management of our animals can be cost-effective, increase productivity and, at the same time, greatly improve the image of meat and milk industries in society and the marketplace.

Animal Feed↗
PubMed2006

Pedigree analysis of an elite rice hybrid using proteomic approach.

The definition of dominance or epistasis is generally on the basis of a descriptive characterization for these crops in the field, such as yield per hectare and the weight of grain. Since these trait examinations lack molecular information, how to precisely predict the phenotypic changes in filial generation is still a problem in heterosis studies. For rice, the genetic information caused by hybridization can be archived through analyzing of proteomes of rice seeds. Differential analysis of proteomes was introduced for the rice seeds of three cultivars, 9311, PA64S and LYP9, an elite rice hybrid from cross between 9311 and PA64S. In the three rice endosperms, the expression profiles of proteins were similar with the stained spots of 47 +/- 1, 46 +/- 0.6 and 44 +/- 0.6, for 9311, PA64S and LYP9, respectively; however, the number of proteins expressed in the rice embryos was significantly increased with the stained spots of 395.3 +/- 12.9, 350 +/- 9.2, and 389.3 +/- 16.4, for 9311, PA64S and LYP9, respectively. Importantly, the image comparisons and protein identifications have revealed in significantly different embryo protein spots among the three rice cultivars. By carefully analyzing these different 2-DE spots, many of them from the three embryos were shown to display a mirrored relationships between parents and the first filial generation. Furthermore, all of stained spots in LYP9 embryo were found on the 2-DEs from its parents, indicating that there was a genetic linkage. These results suggest that proteomic approach is able to serve pedigree analysis and functional prediction for new rice breeds.

Chromosome Mapping↗
PubMed2005

Evaluation of approaches to detect quantitative trait loci for growth, carcass, and meat quality on swine chromosomes 2, 6, 13, and 18. II. Multivariate and principal component analyses.

The merits of complementary multivariate techniques to identify QTL associated with multiple traits were evaluated. Records from 806 F2 pigs pertaining to a Berkshire x Duroc three-generation population were available. Six multitrait groups on SSC 2, 6, 13, and 18 with information on 30 markers were studied. Multivariate techniques studied included multivariate models and principal components analysis of each multitrait group. All models included, in addition to systematic effects, additive, dominance, and imprinting coefficients corresponding to a one-QTL model and a random family effect. Multivariate analysis identified QTL associated with genomewise significant variation in four of the multitrait groups. The majority of the multivariate analysis provided greater precision of parameter estimates and higher statistical significance in some cases than univariate approaches, because of the greater parameterization of the multivariate models and moderate information content of the data. Principal component analysis results were consistent with univariate and multivariate analyses and recovered the levels of statistical significance observed in univariate analyses on the original data. In addition, principal component analysis was able to provide a location associated with LM area not detected by other analyses. The relative advantage of multivariate over the univariate approaches varied with the level of genetic covariance between traits because of the modeled QTL effect and information contained in the data; however, multivariate approaches have the unique capability to identify pleiotropic effects or multiple linked QTL.

Animals↗
PubMed1982

Enzymeimmunoassay of milk-progesterone: its application to oestrus confirmation and early pregnancy diagnosis in cattle.

A solid-phase enzymeimmunoassay (EIA) was developed for progesterone, based on horse radish peroxidase as the enzyme-label and Dasp (sheep anti-rabbit Ig, covalently linked to cellulose) for separation of antibody-bound and free hormone. The validity of the assay was substantiated in accordance with criteria for sensitivity, precision, accuracy and specificity; it is simple to perform and can be done in one day. Milk samples were taken on the day of A.I. (day 0) and on day 21 from 60 dairy cows which belonged to an artificial insemination (A.I.) station in the central part of Thailand. Conception rate (C.R.) after first A.I., as diagnosed by the milk-progesterone test, was 31.7 per cent. Based on rectal exploration on day 84-93 and on 'non-return' at 85 days. C.R. was 20.0 per cent and 23.3 per cent, respectively. All animals except one showed non-luteal phase progesterone levels at the time of A.I. It is concluded that low C.R. in these cows is not due to inseminations during the luteal phase of the oestrous cycle.

Animals↗
PubMed1992

Amplexus induces surge of luteinizing hormone in male toads, Bufo japonicus.

At mating time in the wild, male toads (Bufo japonicus) exhibit a surge in circulating luteinizing hormone (LH) that is thought to result in spermiation. Experiments were performed to identify proximate control of this gonadotropin surge. Male toads migrating to a breeding pond were captured and put in plastic containers either with equal numbers of females or without females. All the males placed with the females clasped them in amplexus that lasted for about 12 hr. During this period, plasma LH and follicle-stimulating hormone levels increased progressively to about 25 and 2 times the initial levels, respectively, and then returned to the initial levels. No significant increases in plasma gonadotropin levels were observed in the males kept without females. These results suggest that the amplexus directly induced the LH surge, but do not preclude control by pheromonal or visual stimuli. To isolate effects of these factors, solitary male toads were kept with dummies of the female. The dummy was a block of "konnyaku," Japanese food whose component is mannan extracted from the root of a plant. Konnyaku is highly elastic, white in color, and virtually odorless. Thus, these dummies felt, but did not look or smell, realistic. All the males clasped their dummy and formed amplexus for 12 hr or more; an LH surge indistinguishable from that with the females was observed. It is concluded that the amplexus itself is the stimulus that induces the LH surge, and subsequent spermiation, in male toads. A strongly male-biased sex ratio, combined with a need to time spermiation precisely with actual mating, may have resulted in the evolution of this neuroendocrine reflex in male Bufo.

Animals↗
PubMed1999

[Oocyte of domestic mammals: a model for the study of in vitro maturation].

Oocyte maturation represents the final step of a long differentiation process that allows this very special cell to fully express its reproductive task. During maturation the oocyte nucleus, blocked at the late prophase of meiosis from the end of foetal life, resumes meiosis and progress to the metaphase II stage. Beyond these nuclear aspects, oocyte maturation also involves cytoplasmic modifications including well known morphological progression as well as poorly understood biochemical changes that are determinant for successful fertilisation and early embryo development. In physiological conditions, maturation occurs in the preovulatory follicle after the ovulatory surge of gonadotropins, in a complex and changing environment. This complexity leaded to the formulation of the first in vitro maturation systems involving tissue culture media supplemented with biological fluids. A more precise study of the effect of individual medium components allowed the design of more simple maturation conditions providing more reproducible results with less sanitary risks. Amongst maturation activating factors, the epidermal growth factor (EGF) seems to play a key function in several species. Other factors such as hormones, ovarian peptides (inhibin, activin) and other growth factors may also be involved but the interplay between these factors remains to be clearly established. Improvement of in vitro maturation techniques allowed to evaluate the importance of oocyte intrafollicular differentiation before maturation on the resulting developmental competence. The increased knowledge of the regulation of intrafollicular meiotic arrest now allow the design of a prematuration step to allow oocytes from smaller follicles to complete their differentiation in vitro. This improvement will allow a larger use of the huge reproductive potential stored in the ovary.

Animals↗
PubMedDate not supplied

Morphology of ventricular arrhythmias in the boxer as measured by 12-lead electrocardiography with pace-mapping comparison.

The QRS amplitude and polarity were determined in 12-lead electrocardiograms recorded from 22 Boxers with ventricular arrhythmias. Eighty-one percent (18/22) of dogs displayed a positive QRS morphology in the caudoventral leads (II, III, and aVF) and 77% (17/22) of dogs displayed a positive QRS morphology in the left precordial leads (V2-V6). In leads I and V1, the polarity of the QRS complex was variable (positive or negative). To determine if these morphologic features were suggestive of ventricular complexes arising from the right or left ventricle, a comparison was made to the QRS complexes in a pace-mapping study performed in 7 healthy mixed-breed dogs. A total of 3 right and 4 left ventricular sites were paced. None of the left ventricular paced sites resulted in a QRS morphology similar to the most common spontaneous ventricular arrhythmia in the Boxers. In contrast, QRS morphology in each of the 3 right ventricular sites was similar to that observed in the Boxers (P < .033). Each of these produced positive deflections in the caudoventral and left precordial leads, but both positive and negative QRS complexes were observed in leads I and V1 only when the right ventricular septum was paced. This finding suggested that the right ventricular septum might be a site of origin for the ventricular rhythm observed in the Boxers because in the Boxers the polarity of leads I and V1 also varied. Pacing the right ventricular outflow tract always resulted in a negative QRS complex in lead 1, whereas pacing the right ventricular apex always resulted in a positive QRS complex in lead I and a negative QRS complex in V1. However, these locations cannot be excluded as possible sites of origin for the spontaneous ventricular arrhythmias in the Boxers because the arrhythmias could be originating from both of these locations. The spontaneous ventricular arrhythmia of the Boxer is most similar to that of paced ventricular rhythms arising from the right ventricle. More precise localization to a region of the right ventricle such as outflow tract, septal, or apical could not be made.

Animals↗
PubMedDate not supplied

Frost injury prediction model for Douglas-fir seedlings in the Pacific Northwest.

Because simple seed- or breeding-zone guidelines are inadequate for controlling the risk of maladaptation to environmental stresses, we are developing operational procedures to assess the risk of frost kill to genetically improved families of Douglas-fir (Pseudotsuga menziesii Mirb. Franco). We have (1) determined the time course of cold hardening and dehardening of nursery-grown Douglas-fir seedlings over four winters, by means of controlled freezing tests, (2) fitted curves to relationships between temperature sum and both fall cold hardening and spring dehardening, (3) applied the temperature sum models to daily temperature records of 80 weather stations to estimate frequency of years with significant frost kill at those stations, (4) interpolated frost kill probabilities for tree farms, using a thin plate spline procedure with elevation, latitude and longitude as variables, and (5) prepared a coarse-scale frost risk map from the resulting grid point estimates. With the exception of a few high-elevation stations, the most damaging frost at any station in any year occurred in either the fall (October and November) or late spring (mid-April to mid-May). In general, damaging spring frosts were two to three times more frequent than fall frosts, and areas in Oregon were at greater risk than areas at similar elevations and longitudes further north. The spline surface was less precise for predicting spring frost risk than fall frost risk.

Journal Article↗
PubMed2005

Smart portable rehabilitation devices.

BACKGROUND: The majority of current portable orthotic devices and rehabilitative braces provide stability, apply precise pressure, or help maintain alignment of the joints with out the capability for real time monitoring of the patient's motions and forces and without the ability for real time adjustments of the applied forces and motions. Improved technology has allowed for advancements where these devices can be designed to apply a form of tension to resist motion of the joint. These devices induce quicker recovery and are more effective at restoring proper biomechanics and improving muscle function. However, their shortcoming is in their inability to be adjusted in real-time, which is the most ideal form of a device for rehabilitation. This introduces a second class of devices beyond passive orthotics. It is comprised of "active" or powered devices, and although more complicated in design, they are definitely the most versatile. An active or powered orthotic, usually employs some type of actuator(s). METHODS: In this paper we present several new advancements in the area of smart rehabilitation devices that have been developed by the Northeastern University Robotics and Mechatronics Laboratory. They are all compact, wearable and portable devices and boast re-programmable, real time computer controlled functions as the central theme behind their operation. The sensory information and computer control of the three described devices make for highly efficient and versatile systems that represent a whole new breed in wearable rehabilitation devices. Their applications range from active-assistive rehabilitation to resistance exercise and even have applications in gait training. The three devices described are: a transportable continuous passive motion elbow device, a wearable electro-rheological fluid based knee resistance device, and a wearable electrical stimulation and biofeedback knee device. RESULTS: Laboratory tests of the devices demonstrated that they were able to meet their design objectives. The prototypes of portable rehabilitation devices presented here did demonstrate that these concepts are capable of the performance their commercially available but non-portable counterparts exhibit. CONCLUSION: Smart, portable devices with the ability for real time monitoring and adjustment open a new era in rehabilitation where the recovery process could be dramatically improved.

Journal Article↗
PubMed2004

Genetic analysis and mapping of resistance to lettuce dieback: a soilborne disease caused by tombusviruses.

A diverse collection of modern, heirloom and specialty cultivars, plant introduction (PI) accessions, and breeding lines of lettuce were screened for susceptibility to lettuce dieback, which is a disease caused by soilborne viruses of the family Tombusviridae. Susceptibility was evaluated by visual symptom assessment in fields that had been previously shown to be infested with Lettuce necrotic stunt virus. Of the 241 genotypes tested in multiple field experiments, 76 remained symptom-free in infested fields and were therefore classified as resistant to dieback. Overall, resistant genotypes were as prevalent among modern cultivars as in heirloom cultivars or primitive germplasm. Within modern germplasm, however, all crisphead (iceberg) cultivars were resistant, while all romaine cultivars were susceptible. Using enzyme-linked immunosorbent assay, tombusviruses were detected in leaves of some plants of resistant genotypes that were grown in infested fields, suggesting that symptom-free plants are not immune to viral infection. The inheritance of resistance was studied for 'Salinas', a modern iceberg cultivar, and PI 491224, the progenitor of recently released romaine germplasm with resistance to lettuce dieback. Resistance was conferred by a dominant allele at a single locus in both genotypes. The tombusvirus resistance locus from 'Salinas', Tvr1, was mapped in an intraspecific Lactuca sativa population to a location that corresponds to linkage group 2 on the consensus map of Lactuca. The largest cluster of resistance genes in lettuce, the Dm1/Dm3 cluster, is found on this linkage group; however, the precise position of Tvr1 relative to this cluster has not yet been determined. To our knowledge, Tvr1 is the first tombusvirus resistance gene identified for any plant host.

Chromosome Mapping↗
PubMed2005

Parentage versus two-generation analyses for estimating pollen-mediated gene flow in plant populations.

Assessment of contemporary pollen-mediated gene flow in plants is important for various aspects of plant population biology, genetic conservation and breeding. Here, through simulations we compare the two alternative approaches for measuring pollen-mediated gene flow: (i) the NEIGHBORHOOD model--a representative of parentage analyses, and (ii) the recently developed TWOGENER analysis of pollen pool structure. We investigate their properties in estimating the effective number of pollen parents (N(ep)) and the mean pollen dispersal distance (delta). We demonstrate that both methods provide very congruent estimates of N(ep) and delta, when the methods' assumptions considering the shape of pollen dispersal curve and the mating system follow those used in data simulations, although the NEIGHBORHOOD model exhibits generally lower variances of the estimates. The violations of the assumptions, especially increased selfing or long-distance pollen dispersal, affect the two methods to a different degree; however, they are still capable to provide comparable estimates of N(ep). The NEIGHBORHOOD model inherently allows to estimate both self-fertilization and outcrossing due to the long-distance pollen dispersal; however, the TWOGENER method is particularly sensitive to inflated selfing levels, which in turn may confound and suppress the effects of distant pollen movement. As a solution we demonstrate that in case of TWOGENER it is possible to extract the fraction of intraclass correlation that results from outcrossing only, which seems to be very relevant for measuring pollen-mediated gene flow. The two approaches differ in estimation precision and experimental efforts but they seem to be complementary depending on the main research focus and type of a population studied.

Computer Simulation↗
PubMed2006

"Clean, green and ethical" animal production. Case study: reproductive efficiency in small ruminants.

In response to changes in society and thus the marketplace, we need a vision for the future of our animal industries, including both on-farm and off-farm activities, that is "clean, green and ethical". Using small ruminants as a case study, we describe three "clean, green and ethical" strategies that farmers could use to improve reproductive performance. The first allows control of the timing of reproductive events by using socio-sexual signals (the "male effect") to induce synchronised ovulation in females. The second strategy, "focus feeding", is based on using short periods of nutritional supplements that are precisely timed and specifically designed for each event in the reproductive process (eg, gamete production, embryo survival, fetal programming, colostrum production). The third strategy aims to maximize offspring survival by a combination of management, nutrition and genetic selection for behaviour (temperament). All of these approaches involve non-pharmacological manipulation of the endogenous control systems of the animals and complement the detailed information from ultrasound that is now becoming available. Importantly, these approaches all have a solid foundation in reproductive biology. In several cases, they are currently used in commercial practice, but there is still room for improvement through both basic and applied research. Ultimately, these "clean, green and ethical" tools can be cost-effective, increase productivity and, at the same time, greatly improve the image of meat and milk industries in society and the marketplace.

Animal Husbandry↗