bluuebunny/crossref_metadata_2025_split huggingface dataset:
A decision algorithm for patch spraying
Authors: Christensen S , Heisel T , Walter A M , Graglia E 
Published: July 2003

SummaryIt has been established that weeds are spatially aggregated with a spatially varying composition of weed species within agricultural fields. Site‐specific spraying therefore requires a decision method that includes the spatial variation of the weed composition and density. A computerized decision method that estimates an economic optimal herbicide dose according to site‐specific weed composition and density is presented in this paper. The method was termed a ‘decision algorithm for patch spraying’ (DAPS) and was evaluated in a 5‐year experiment, in Denmark. DAPS consists of a competition model, a herbicide dose–response model and an algorithm that estimates the economically optimal doses. The experiment was designed to compare herbicide treatments with DAPS recommendations and the Danish decision support system PC‐Plant Protection. The results did not show any significant grain yield difference between DAPS and PC‐Plant Protection; however, the recommended herbicide doses were significantly lower when using DAPS than PC‐Plant Protection in all years. The main difference between the two decision models is that DAPS integrates crop–weed competition and estimates the net return as a continuous function of herbicide dose. The hypothesis tested is that the benefit of using lower herbicide doses recommended by DAPS would disappear after a few years because weed density will increase and thus require higher doses. However, the results of weed counting every year did not confirm this hypothesis.
Relationship between speed, soil movement into the cereal row and intra‐row weed control efficacy by weed harrowing
Authors: Cirujeda A , Melander B , Rasmussen K , Rasmussen I A 
Published: July 2003

SummaryField trials were carried out at a single Danish and two Spanish locations. In Denmark, winter wheat was sown at 24‐cm row spacing allowing hoeing in the inter‐row area. Hoeing speeds of 2, 5 and 8 km h−1 were tested at the end of tillering, at the beginning of stem elongation or on both occasions. The crop was harrowed immediately after hoeing at the same speed. At the Spanish locations the winter barley was sown at a 12‐cm row spacing and harrowed only, at either pre‐emergence plus post‐emergence, or once post‐emergence at mid‐tillering at 2, 4, 6 and 8 km h−1. The depth of the soil layer thrown into the cereal row was measured at all locations. This layer ranged between 0.4 and 1.4 cm, depending on the site and on the treatment, but was generally higher following a single harrow treatment at all sites. The soil layer only tended to increase with faster speeds at the Danish location. On a more sandy soil and soil rolled prior to treatment, less soil was thrown into the cereal row. When two hoe + harrowing treatments were made, a finer soil structure was achieved. However, this did not affect the weed control. At the Danish location, initial intra‐row weeding efficacy of Brassica napus, based on plant number before and 7 days after treatment, was found to be low (21–41%) but increased to 74–79% when assessed after 45 days. Partial burial and bending of B. napus, together with crop competition, probably suppressed weed growth and enhanced final mortality. Uprooting was probably a more important cause of mortality for Stellaria media. At the Spanish locations, weeding efficacy of Papaver rhoeas was similar, ranging between 58% and 83% and this was achieved soon after harrowing. A thicker soil layer did not result in a greater weed kill. It was therefore suggested that burial alone could not be the main factor responsible for weed control in any of the cases studied. No reduction in wheat biomass, measured at the end of May, was found with increasing speed, or with repeated passes of the harrow. The results suggested that faster harrowing, which is economically more attractive for farmers, could be recommended. The soil layer thrown into the row was not found to be a useful parameter to predict the weed control efficacy in the cases presented.
Genetic uniformity of Alternanthera philoxeroides in South China
Authors: Ye W H , Li J , Cao H L , Ge X J 
Published: July 2003

Summary Alternanthera philoxeroides (Mart.) Grisb is an invasive weed that is widespread in a variety of habitats around the world. It was introduced into China in the 1930s, and today occurs in 20 provinces. The level and pattern of genetic diversity of 193 individuals from 11 land‐grown A. philoxeroides populations from South China were determined using 81 intersimple sequence repeat markers. Mean Nei's gene diversity (HE) was 0.0203 ± 0.008, and total diversity (HT) was 0.0286, indicating that genetic diversity in A. philoxeroides in South China is very low. There was a greater proportion of diversity within populations than among (GST =  0.292) populations. Gene flow (Nm) among populations was 0.607. These results are in accordance with the assumption that populations in South China are genetically depauperate because of the short introduction history and the partially clonal propagation of this weed.
Hymenopterous parasitoids of the cherry bark tortrix, Enarmonia formosana (Scopoli) in central‐east Europe (Hymenoptera, Ichneumonoidea; Lepidoptera, Tortricidae)
Authors: Tanigoshi L. K. , Starý P. 
Published: July 2003

AbstractStrategies targeting the biological control of the cherry bark tortrix (=CBT), Enarmonia formosana (Scopoli) in North America have also included the search for potentially useful native hymenopterous parasitoids of the pest in Europe. The search for such agents undertaken in the central‐east Europe (Czech Republic, Slovak Republic, Hungary) resulted in determination of several ichneumonid species (Campoplex cf. dubitator Horst., Liotryphon sp., Lissonotus sp., Pimpla spuria (Grav.), Pimpla turionellae (L.), and some others, and a braconid (Apanteles britannicus Wilk.) in 2001–2002.
Overview of development of an anti‐attractant based technology for spruce protection againstIps typographus: From past failures to future success
Authors: Jakuš R. , Schlyter F. , Zhang Q.‐H. , Blaženec M. , Vaverčák R. , Grodzki W. , Brutovský D. , Lajzová E. , Turčáni M. , Bengtsson M. , Blum Z. , Gregoiré J.‐C. 
Published: July 2003

AbstractWe describe a series of experiments on the protection of Norway spruce (Picea abies(L.) Karst.) logs and standing trees againstIps typographusL. (Coleoptera: Scolytidae). The tested protective materials were applied 1) at point sources and 2) area‐covering using zeolite‐based dispensers. We performed 11 terrestrial and one aerial application (using a helicopter) between 1992 and 2001. We gradually replaced polyethylene‐bag verbenone dispensers by composite dispensers releasing verbenone and non‐host volatiles (NHV: green leaf volatiles,trans‐conophthorin, and C8‐alcohols). Many experiments did not give statistically significant results, due to the low number of true replicates and the spatial heterogeneity of beetle attacks. The protection of horizontal objects like logs or lying trees with anti‐attractants was not always successful. In the future, positive results can be expected with an area covering spray applied by zeolite dispensers containing mixtures of verbenone and NHV. A similar approach could probably be used in aerial spraying of anti‐attractants.We have succeeded in our attempt to protect zones of standing spruce trees fromI. typographusattacks. We used dispensers with a combination of verbenone and a full blend of NHV compounds. The protection is not complete, but in both 2000 and 2001, the treatment significantly decreased the probability of the insect attack on trees by 60–80 %.
Analysis of two Chinese yak (Bos grunniens) populations using bovine microsatellite primers
Authors: Minqiang Wang , Weigend S. , Barre‐Dirie A. , Carnwath J. W. , Zhonglin L. , Niemann H. 
Published: July 2003

SummaryTwo Chinese domestic yak populations representing the Plateau type and the Huanhu Alpine type were analysed with 12 bovine microsatellite primers. All primer pairs functioned in the yak genome and polymorphism was found at all loci. The allele size ranges and frequencies of the two yak populations were similar and there was considerable overlap with the allele size ranges observed in cattle. Data for European cattle breeds was obtained from the Cattle Diversity Database (CaDBase) to interpret the heterozygosity and genetic distance estimates in yak populations. Heterozygosity estimated for the two yak populations was comparable with that of European cattle while Nei's Genetic Distance DA between the two yak populations was less than distances between the most closely related German cattle breeds. Bovine microsatellite primers proved to be a valuable tool for characterization of yak populations.
Early growth performance of Bos taurus × Bos indicus cattle crosses in Ethiopia: estimation of individual crossbreeding effects
Authors: Demeke S. , Neser F. W. C. , Schoeman S. J. 
Published: July 2003

SummaryIn an effort to estimate breed differences, heterotic and recombination effects, a total of 4957 birth weight (BWT), 4245 weaning weight (WWT) and 3330 yearling weight (YWT) records collected from 38 crossbred and three purebred genotypes generated from crossing Friesian (F), Jersey (J) and Simmental (S) with the Boran (Bo), Barca (Ba) and Horro (Ho) (Bos indicus) breeds in Ethiopia were used. Differences between genotypes were significant (p < 0.01) for all traits. Genetic group mean values adjusted for environmental effects ranged from 20 to 30 kg for BWT, 88 to 114 kg for WWT, 122 to 157 kg for YWT and 358 to 492 g for preweaning average daily gain (ADG). The breed additive effect of F as a deviation from the Bo was significant (p < 0.01) and positive for all traits. Relative to the Bo mean, the additional breed additive contributions of the F breed on BWT, WWT, ADG and YWT were 39.3, 16.5, 9.3 and 10.3%, respectively. However, the breed additive effects of the Ho and J breeds were significantly (p < 0.01) negative for all traits. The heterotic effects were significantly negative (p < 0.01) for BWT for all F and S crosses, but positive (p < 0.01) on all other traits for all types of crosses. The average heterosis estimated within the F, J and S breeds were: −2.1 ± 0.6, 0.2 ± 0.6 (p > 0.05) and −2.3 ± 0.6 kg for BWT, 8.82.1, 11.8 ± 2.3 and 13.7 ± 2.4 kg for WWT, 60.4 ± 11.3, 64.8 ± 12.3 and 90.6 ± 12.7 g for ADG, and 19.8 ± 2.6, 19.5 ± 2.8 and 20.8 ± 2.9 kg for YWT, respectively. The recombination effects were significant (p < 0.01) for the majority of crosses for all traits. The estimates of the recombination loss were negative in all traits, except for BWT. The average recombination effects estimated within the F, J and S breeds were: 2.6 ± 0.8, 2.9 ± 0.9 and 2.4 ± 1.0 kg for BWT, −13.6 ± 3.2, −4.2 ± 3.4 (p > 0.05) and −16.0 ± 4.0 kg for WWT, −88.0 ± 17.1, −39.4 ± 18.4 and −102.2 ± 21.3 g for ADG, and −14.4 ± 4.0, −0.1 ± 4.4 (p > 0.05) and −17.5 ± 4.9 kg for YWT, respectively. It could be concluded that the breed differences, heterotic and recombination effects seem to be important genetic factors affecting early growth performances in the breed crosses tested.
Genetic parameters of somatic cell count in dairy sheep considering the type of mammary pathogen effect
Authors: Gonzalo C. , Ariznabarreta A. , Othmane M. H. , Carriedo J. A. , De La Fuente L. F. , San Primitivo F. 
Published: July 2003

SummaryGenetic parameters for somatic cell count (SCC) from half‐udder milk were estimated from 4692 monthly test‐day records from each half‐udder of 1337 Churra ewes belonging to seven dairy flocks. The total number of observations was 9348. Variance and co‐variance genetic components were estimated using a multitrait repeatability animal model. The log SCC of the right and left half‐udders were considered as two dependant variables in the model. The species of organisms causing intramammary infection were identified and included or not in the analysis as a fixed effect. The inclusion of the mammary pathogen fixed effect did not influence the estimation of heritability. However, the proportions of permanent environmental variance and repeatability were significantly reduced in comparison with the model that did not include this effect. On the other hand, the genetic correlation between SCC in milk from left and right glands was close to unity, and no differences were detected between both glands for all genetic estimates. The importance of the mammary pathogen factor was evaluated in comparison with the other fixed effects studied, which in relation were of little importance.
Bayesian analysis of heritability of canine hip dysplasia in German Shepherd Dogs
Authors: Hamann H. , Kirchhoff T. , Distl O. 
Published: July 2003

SummaryVariance components and heritability were linearly estimated for canine hip dysplasia (CHD) in German Shepherd Dogs using a Bayesian analysis based on the marginal posterior distributions of parameters achieved via Gibbs sampling. Data was provided by the German Shepherd Breeding Association in Augsburg. The material included 21 371 X‐rayed dogs born in the years 1998–2000 in 3755 kennels from 9704 litters. The pedigree file consisted of 38 604 animals and contained ancestors for up to six generations. The full model used considered the fixed effects of sex, age at examination for CHD, the examining veterinary expert, the combined effect of litter size and percentage of examined dogs per litter, and the sire and mother lines as well as the additive genetic random effects of the animal and of the mother, the permanent environmental effect of the litter and the kennel. Submodels were compared with the full model to evaluate the importance of different fixed and random effects, and their influence on other model components. Heritability estimates in the full model wereh2 = 0.26 ± 0.03 (additive genetic animal effect) and = 0.10 ± 0.02 (additive genetic maternal effect). The direct animal and the maternal effects were negatively correlated genetically (ram = −0.65 ± 0.05). The proportion of the variance of the random effect of the common kennel of the total variance was always below 0.015, whereas the corresponding proportion of variance of the random effect of the common litter effect reached a value of 0.045. When submodels were employed, the heritability estimates for the additive genetic animal effect ranged fromh2 = 0.24 toh2 = 0.26. The heritability estimates for the additive genetic maternal effect varied between = 0.09 and = 0.10.
Genetic change of feed intake curves in growing pigs using non‐linear two‐stage genetic analysis and linear random regression models
Authors: Lorenzo Bermejo J. , Roehe R. , Schulze V. , Looft H. , Kalm E. 
Published: July 2003

SummaryLongitudinal data of daily feed intake from 5245 young boars were analysed in this study in order to improve feed efficiency by changing the feed intake curve. Individual logistic and linear‐segmented functions were fitted, based on daily data of feed intake per boar, recorded during a test period of 9 weeks. Heterogeneous variance was considered by means of the power‐of‐the‐mean variance model. The mean estimated day on test corresponding to maximum increment in feed intake varied from 71 to 81 days using logistic function, and the mean estimated day on test at which the feed intake plateau was reached varied from 45 to 48 days on test, using a linear‐segmented function. High differences in the individual variation pattern of feed intake were obtained. A mixed model was fitted to individual estimates of function parameters. The uncertainty in individual estimation was taken into account by incorporating the estimated asymptotic covariance matrices. Estimates of heritability for parameters characterizing feed intake at the beginning of the test period ranged from 0.03 to 0.30. Selection based on parameters of a logistic function, using absolute residual estimation of variance heterogeneity, reduced feed intake at the end of the test period by 0.2 kg/day, while feed intake at the beginning of the test was slightly modified. With increasing individual information on daily feed intake, the two‐stage method was recommended. If individual observations on daily feed intake are sparse, random regression models were preferred in order to change the feed intake curve for breeding purposes.
Phenotypic correlations as substitutes to genetic correlations in dairy sheep and goats*
Authors: Kominakis A. P. 
Published: July 2003

SummaryA data set of n = 67 pairs of genetic and phenotypic correlation estimates for various milk traits, constructed from an exhaustive survey of published estimates in dairy sheep and goats, was used to test whether the phenotypic correlation (rP) may be a suitable replacement of the genetic correlation (rG). Various criteria to assess the closeness of the two estimates were used: Pearson‐, Spearman‐ and bootstrapped‐ correlations, paired sample t‐test and non‐parametric tests. Correlations between paired genetic and phenotypic correlation estimates were generally found to be high (from 0.87 to 0.95) and not statistically different between the two species. Employment of a paired sample t‐test showed that the average difference between the genetic and phenotypic correlation estimates (d = rG − rP) was significantly (p < 0.05) different from zero only for dairy goats (d = 0.11). Comparisons of correlation estimates either after employment of Fisher's transformation or of a non‐parametric test (Kruskall–Wallis) showed that there was statistically no significant difference (p < 0.05) between the two estimates. The main sources of variation for pooled (sheep and goat) d were the year of publication, the method of estimation and the heritabilities of the traits. Furthermore, differences between the two estimates were caused by sampling errors of the genetic correlations. Although average reported standard errors of genetic correlations were found to be about 30% higher than the theoretically expected correlations, the difference between the two errors was not statistically significant (p < 0.05). A simulation study of two correlated traits displaying heritabilities, genetic, environmental and phenotypic correlations equal to the average literature estimates was also performed to investigate the effects of using rP instead of rG on the direct and indirect true selection responses and on the accuracy of the breeding values. Based on the results of the descriptive and simulation analysis for the species, traits and correlation structure examined here, phenotypic correlations may be substituted for genetic correlations when the latter are unavailable or are not precisely estimated.
Serum insulin‐like growth factor‐1 concentration in pigs divergently selected for daily food intake or lean growth rate
Authors: Cameron N. D. , McCullough E. , Troup K. , Penman J. C. 
Published: July 2003

SummaryDivergent selection over seven generations for daily food intake (DFI) and for two lean growth rate (LGA and LGS) selection objectives in pigs produced correlated responses in serum insulin‐like growth factor‐1 (IGF‐1) concentration. The LGA and LGS selection objectives were for lean growth, but with performance testing on ad libitum (LGA) or on restricted (LGS) feeding regimes. There were 342 animals in the study, with an average of 46 pigs in each selection line and 72 pigs in the control line. All animals were performance‐tested from 30 to 90 kg on an ad libitum feeding regime. Selection on DFI increased IGF‐1 at 6 weeks of age (158 versus 104 μg/l, SED 21; control 136 μg/l) and selection for high LGA increased IGF‐1 at 30 kg liveweight (202 versus 161 μg/l, SED 14; control 185 μg/l). At 6 weeks of age and at 30 kg of weight, there was no response in IGF‐1 with selection on LGS (128 versus 129 and 167 versus 153 μg/l, respectively) suggesting that IGF‐1 may not be a reliable physiological predictor of genetic merit for such a selection objective, which combined rate and efficiency of lean growth. IGF‐1 measured immediately prior to the start of performance test may be useful in determining which animals to performance test for a lean growth selection objective, whereas IGF‐1 measured at 6 weeks of age may be a useful physiological predictor of genetic merit for daily food intake during performance test.
Experimental Field Trial with an Immunostimulating Complex (ISCOM) Vaccine against Contagious Bovine Pleuropneumonia
Authors: Hübschle O. J. B. , Tjipura‐Zaire G. , Abusugra I. , Di Francesca G. , Mettler F. , Pini A. , Morein B. 
Published: July 2003

SummaryThe experimental field trial with an immunostimulating complex (ISCOM) vaccine has been an occasion to explore the role of a Th1 response in the pathogenesis caused by Mycoplasma mycoides subsp. mycoides small colony (MmmSC) and in immune protection. The ISCOM complex is known to promote Th1 response. Antibodies to MmmSC were detected by indirect enzyme‐linked immunosorbent assay (ELISA) in the vaccinated cattle, although the levels were lower than in a previous study. No antibodies were detected by complement fixation test (CF). After the challenge infection, vaccinated animals developed CF antibody response. They showed significantly reduced mortality compared with controls. However, gross pathological and histopathological score for vaccinated animals was as high as for the non‐vaccinated, characterized by a high inflammatory reaction with histopathology dominated by interlobular pneumonia with vasculitis.
Atypical Myxomatosis – Virus Isolation, Experimental Infection of Rabbits and Restriction Endonuclease Analysis of the Isolate
Authors: Pšikal I. , Šmíd B. , Rodák L. , Valíček L. , Bendová J. 
Published: July 2003

SummaryAtypical form of myxomatosis, which caused non‐lethal and clinically mild disease in domestic rabbits 1 month after immunization with a commercially available vaccine MXT, is described. The isolated myxoma virus designated as Litovel 2 (Li‐2) did not induce systemic disease following subcutaneous and intradermal applications in susceptible experimental rabbits but led to the immune response demonstrated by ELISA. No severe disease was induced in those Li‐2 inoculated rabbits by challenge with the virulent strains Lausanne (Lu) or Sanar (SA), while the control animals showed nodular form of myxomatosis with lethal course of the illness. Restriction fragment length polymorphism (RFLP) of genomic DNA with KpnI and BamHI endonucleases was used for genetic characterization of the Li‐2 isolate, the vaccine strain MXT and both virulent strains Lu and SA, respectively. In general, RFLP analysis has shown to be informative for inferring genetic relatedness between myxoma viruses. Based on restriction endonuclease DNA fragment size distribution, it was evident that the pathogenic strain SA is genetically related to the reference strain Lu and the isolate Li‐2 is more related, but not identical, to the vaccination strain MXT.