Stadler C.,Agricultural University of Iceland |
Helgadottir A.,Agricultural University of Iceland |
Agustsson M.A.,Farmers Association of Iceland |
Riihimaki M.-A.,HAMK University of Applied Sciences
Acta Horticulturae | Year: 2012
The extremly low natural light level is the major limiting factor for winter glasshouse production in Iceland. Therefore, supplementary lighting is essential to maintain year-round production. The energy costs could be decreased by lighting during the cheaper night tariff as well as during whole weekends. The objective of the study was to test whether decreasing energy costs by lighting at cheaper times will result in satisfactory yields. Sweet pepper (Capsicum annuum L. 'Ferrari', 9 stems/m2 and 'Viper', 6 stems/m 2) and tomatoes (Lycopersicon esculentum Mill. 'Encore', 2.5 plants/m2) were grown in two growth cabinets under high-pressure vapour sodium lamps for a maximum of 18 hours light. During the period of high electrical costs for time dependent tariffs one cabinet got supplemental light during the night and during the whole weekend, whereas during the other months it was uniformly provided from 04-22 h as in the other cabinet. Temperature was kept at 24-25/17-20°C (day/night) for sweet pepper and at 22-23/18-19°C (day/night) for tomatoes. When sweet pepper received light during nights and weekends marketable yield was 5-10% lower compared to the normal lighting time. However, when normal lighting time had been restored, the yield continuously approached the yield of the traditional lighting time. In contrast, accumulated marketable yield of tomatoes that received light during nights and weekends did not approach the yield obtained at normal lighting time with final yields amounting to about 15% less yield. From an economic viewpoint it is recommended to provide light at normal times. © ISHS 2012.
Allais-Bonnet A.,French National Institute for Agricultural Research |
Grohs C.,French National Institute for Agricultural Research |
Medugorac I.,Ludwig Maximilians University of Munich |
Krebs S.,Ludwig Maximilians University of Munich |
And 46 more authors.
PLoS ONE | Year: 2013
Despite massive research efforts, the molecular etiology of bovine polledness and the developmental pathways involved in horn ontogenesis are still poorly understood. In a recent article, we provided evidence for the existence of at least two different alleles at the Polled locus and identified candidate mutations for each of them. None of these mutations was located in known coding or regulatory regions, thus adding to the complexity of understanding the molecular basis of polledness. We confirm previous results here and exhaustively identify the causative mutation for the Celtic allele (PC) and four candidate mutations for the Friesian allele (PF). We describe a previously unreported eyelash-and-eyelid phenotype associated with regular polledness, and present unique histological and gene expression data on bovine horn bud differentiation in fetuses affected by three different horn defect syndromes, as well as in wild-type controls. We propose the ectopic expression of a lincRNA in PC/p horn buds as a probable cause of horn bud agenesis. In addition, we provide evidence for an involvement of OLIG2, FOXL2 and RXFP2 in horn bud differentiation, and draw a first link between bovine, ovine and caprine Polled loci. Our results represent a first and important step in understanding the genetic pathways and key process involved in horn bud differentiation in Bovidae. © 2013 Allais-Bonnet et al.
Einarsson E.,Agricultural University of Iceland |
Eythorsdottir E.,Agricultural University of Iceland |
Smith C.R.,Cedar Creek Company Unit |
Jonmundsson J.V.,Farmers Association of Iceland
Animal | Year: 2014
A total of 862 lamb carcasses that were evaluated by both the VIAscan ® and the current EUROP classification system were deboned and the actual yield was measured. Models were derived for predicting lean meat yield of the legs (Leg%), loin (Loin%) and shoulder (Shldr%) using the best VIAscan® variables selected by stepwise regression analysis of a calibration data set (n=603). The equations were tested on validation data set (n=259). The results showed that the VIAscan® predicted lean meat yield in the leg, loin and shoulder with an R 2 of 0.60, 0.31 and 0.47, respectively, whereas the current EUROP system predicted lean yield with an R 2 of 0.57, 0.32 and 0.37, respectively, for the three carcass parts. The VIAscan® also predicted the EUROP score of the trial carcasses, using a model derived from an earlier trial. The EUROP classification from VIAscan® and the current system were compared for their ability to explain the variation in lean yield of the whole carcass (LMY%) and trimmed fat (FAT%). The predicted EUROP scores from the VIAscan® explained 36% of the variation in LMY% and 60% of the variation in FAT%, compared with the current EUROP system that explained 49% and 72%, respectively. The EUROP classification obtained by the VIAscan® was tested against a panel of three expert classifiers (n=696). The VIAscan® classification agreed with 82% of conformation and 73% of the fat classes assigned by a panel of expert classifiers. It was concluded that VIAscan ® provides a technology that can directly predict LMY% of lamb carcasses with more accuracy than the current EUROP classification system. The VIAscan® is also capable of classifying lamb carcasses into EUROP classes with an accuracy that fulfils minimum demands for the Icelandic sheep industry. Although the VIAscan® prediction of the Loin% is low, it is comparable to the current EUROP system, and should not hinder the adoption of the technology to estimate the yield of Icelandic lambs as it delivered a more accurate prediction for the Leg%, Shldr% and overall LMY% with negligible prediction bias. © 2014 The Animal Consortium.
Sigurdsson A.,Agricultural University of Iceland |
Jonmundsson J.V.,Farmers Association of Iceland
Icelandic Agricultural Sciences | Year: 2011
The aim of the study was to measure the genetic progress in the Icelandic dairy cattle population since the current breeding program started in 1974. The goal was also to estimate the maximum genetic progress to be expected in the future. The data used were the results of the genetic evaluation from July 2010 which included 356,000 animals and all traits. The results showed that the annual genetic progress in dairy traits has been accelerating in recent decades and is now 10% of genetic SD (σG) per year for protein production. This is considerably less than the annual pro-gress of 16% of σG calculated from the component pathways showing what is theoretically possible with the current Artificial Insemination breeding scheme. The most likely explanations for less progress are extensive use of natural service bulls, that are clearly inferior to the AI stock, and the fact that the breeding goal today includes many traits besides milk production. Hence there is considerable genetic progress in all the traits involved.
Dyrmundsson O.R.,Farmers Association of Iceland |
Ninikowski R.,Warsaw University of Life Sciences
Animal | Year: 2010
The short-tailed sheep, native of an area stretching from Russia to Iceland, are generally considered a primitive type. These robust northern sheep seem to have been spread by Norse vikings to several countries in this area from the late eighth century to the middle of the eleventh century ad. They have several common characteristics in addition to the fluke-shaped and tapered short tail, such as a wide range of colour patterns, dual-coated wool and the ability to thrive under harsh environmental conditions, often in isolated marginal areas. While 34 short-tailed breeds of North European origin can still be identified, it is clear that their population sizes have declined in most cases and several of them are now rare and endangered. Although these breeds have mainly been confined to certain localities, some of them have gained considerable distribution due to their genetic merits, such as prolificacy. Of these, the Finnsheep and the Romanov are best known being exported to several countries in the world where their genetic material has been utilized through crossbreeding with local sheep. This has resulted in the production of some new synthetic breeds. Meat is now generally the main product of the North European short-tailed breeds and their crossbreds, whereas wool, skins and milk are normally regarded as byproducts, yet of considerable economic importance in some cases. Such breeds have clearly a role to play in sustainable grassland-based production systems in the future. Copyright © The Animal Consortium 2009.