158 research outputs found

    South Dakota Retained Ownership Demonstration

    Get PDF
    Three hundred forty-five steer calves representing 53 cow-calf producers were consigned to a custom feedlot in late October. Cattle were fed in one of two pens. One pen of calves received a moderate roughage growing diet for 39 days and then were switched to a high energy finishing diet (ACC). The other pen of calves received a moderate roughage growing diet for 109 days and then were switched to a high energy finishing diet (TWO). The ACC calves weighed 574 lb initially, gained 2.94 Ib per head daily and were slaughtered at 1147 Ib after an average of 196 days on feed. Average cost of gain and profitability were 52.31percwtand52.31 per cwt and 38.75 per head, respectively. The TWO calves weighed 504 Ib initially, gained 2.77 Ib per head daily and were slaughtered at 1096 Ib after an average of 214 days on feed. Average cost of gain and profitability were 52.72percwtand52.72 per cwt and 16.69 per head, respectively. Cattle slaughtered later in the spring were less profitable than cattle slaughtered earlier in the spring due to a weaker cattle market and wider choice-select price spread. Across either feeding program, average profits for cattle slaughtered after 170, 192, 199, 200 and 242 days on feed were 50.03,50.03, 64.42, 28.69,28.69, 27.39 and -$16.78 per head, respectively

    Beluga Vocalizations Decrease in Response to Vessel Traffic in the Mackenzie River Estuary

    Get PDF
    Vessel traffic negatively affects marine mammals by causing behavioural disturbance, acoustic masking, contamination (i.e., oil spills), and ship strikes. Few studies have examined the effects of vessels on marine mammals in the Arctic, but beluga whales appear to be especially sensitive to vessel traffic. We examine how the vocalizations of belugas are impacted by vessel traffic in the Tarium Niryutait Marine Protected Area in the Mackenzie River estuary of the western Canadian Arctic. Between one and four acoustic recorders were deployed between June and August each year between 2015 and 2018 near the only shipping channel at this site. We examined beluga vocalizations from acoustic recordings over four summers and assessed how the distance to the nearest vessel passing the acoustic recorder affected the number of vocalizations. Beluga vocalizations within the range of the acoustic recorder decreased significantly when vessels were within 5 km of the acoustic recorder. This result suggests either that belugas are avoiding the vessel or that they reduce their vocalization in response to vessel traffic. Future work is needed to assess exactly how belugas are reacting to vessel traffic in this area and what the long-term consequences of these reactions are. Management measures for reducing these impacts must be carefully considered, especially since these vessels are very restricted in where they can travel, and many of the vessels are necessary for the livelihoods of local communities.La circulation maritime a des effets négatifs sur les mammifères marins, car elle entraîne des perturbations comportementales, masque leurs signaux acoustiques et engendre de la contamination (comme des déversements de pétrole) et des collisions. Bien que peu d’études aient examiné les effets des bateaux sur les mammifères marins de l’Arctique, les bélugas semblent particulièrement sensibles à la circulation maritime. Dans cet article, nous examinons en quoi les vocalisations des bélugas sont touchées par la circulation maritime dans la zone de protection marine de Tarium Niryutait faisant partie de l’estuaire du fleuve Mackenzie, dans l’ouest de l’Arctique canadien. Entre un et quatre enregistreurs acoustiques ont été déployés de juin à août de chaque année entre 2015 et 2018, à proximité du seul chenal de navigation de l’endroit. Nous avons examiné les vocalisations des bélugas prélevées à l’aide des enregistreurs acoustiques au cours de quatre étés, et évalué en quoi la distance du bateau passant le plus près de l’enregistreur acoustique avait un effet sur le nombre de vocalisations. Les vocalisations des bélugas dans la zone de l’enregistreur acoustique diminuaient considérablement lorsque les bateaux se trouvaient à moins de cinq kilomètres de l’enregistreur. Ce résultat suggère soit que les bélugas évitent les bateaux, soit qu’ils réduisent leurs vocalisations en réponse à la circulation maritime. Il y a lieu de pousser cette étude plus loin pour évaluer exactement comment les bélugas réagissent à la circulation des bateaux dans cette région, et quelles sont les conséquences à long terme de ces réactions. Il y a lieu aussi de considérer avec soin des mesures de gestion pour réduire ces incidences, surtout parce que les déplacements de ces bateaux sont assujettis à de nombreuses restrictions et parce que grand nombre des bateaux qui passent par là sont nécessaires à la subsistance des collectivités de la région. &nbsp

    South Dakota Retained Ownership Demonstration

    Get PDF
    Four hundred nineteen steer calves representing 57 cow-calf producers were consigned to a custom feedlot in mid-October. Cattle were fed in one of three pens. One pen of calves was fed a starter program for 20 days followed by a moderate roughage growing diet for 84 days before they were switched to a high energy finishing diet (TWO). The other two pens were fed a starter program for 20 days followed by a moderate roughage growing diet for 14 days before they were switched to a high energy finishing diet. Cattle were sorted into one of these two pens on the basis of whether they had been exposed to feed (AFED, either weaned or creep fed) prior to feedlot arrival or not exposed to feed (ANFED). The TWO calves weighed 500 1b initially, gained 2.80 Ib per head daily, and averaged 1047 1b at slaughter after an average of 196 days on feed. Average cost of gain and profitability were 58.27percwtand58.27 per cwt and 28.74 per head, respectively. The AFED and ANFED calves weighed 539 and 554 Ib initially, gained 3.04 and 3.08 Ib per head daily, and averaged 11 16 and 1136 1b at slaughter after an average of 190 and 189 days on feed, respectively. Average cost of gain and profitability were 55.40and55.40 and 56.32 per cwt and 23.57and23.57 and 33.20 per head, respectively. When data from years 1 and 2 were combined, average daily gain, dressing percentage, quality grade, and cost of gain were related to profitability and accounted for 79.6% of the variation in profitability

    First Evidence for Adoption in California Sea Lions

    Get PDF
    Demographic parameters such as birth and death rates determine the persistence of populations. Understanding the mechanisms that influence these rates is essential to developing effective management strategies. Alloparental behavior, or the care of non-filial young, has been documented in many species and has been shown to influence offspring survival. However, the role of alloparental behavior in maintaining population viability has not been previously studied. Here, we provide the first evidence for adoption in California sea lions and show that adoption potentially works to maintain a high survival rate of young and may ultimately contribute to population persistence. Alloparental behavior should have a positive effect on the population growth rate when the sum of the effects on fitness for the alloparent and beneficiary is positive

    Europa im Geflecht der Welt

    Get PDF
    Der Band dokumentiert Vorträge und Workshops der internationalen Abschlusstagung des DFG-Schwerpunktprogrammes 1173 „Integration und Desintegration der Kulturen im europäischen Mittelalter“, die Ende Mai 2011 in Berlin stattgefunden hat. Bei der Arbeit im Schwerpunktprogramm hatte sich gezeigt, wie schwierig es ist, Europa im geographischen und historischen Sinne vom Mittelmeerraum mit Nordafrika und Vorder¬asien zu trennen. Daher wurden die Grenzen des mittelalterlichen Europa bewusst überschritten und auch die Geschichte weiter entfernter Länder in den Blick genommen. Als thematischer Schwerpunkt boten sich in diesem Zusammenhang Migrationen an. Migrationen sind ja ein globales Phäno¬men, das an allen Orten und zu allen Zeiten immer wieder die Geschichte der Menschheit prägt und dabei unvermeidlich – selbst in der scheinbaren Isolation einer „Diaspora“ oder „Parallelgesellschaft“ – zu transkulturellen Verflechtungen führt. Fremde und einheimische Gruppen und Individuen werden in neue soziale Umgebungen gerückt und Kontakte oder Konflikte zwischen ihnen erzeugt. Wo aber das jeweilige Leben gegeneinander abgeschottet werden soll, verliert Kultur ihre Inno¬vations¬kraft und versteinert die Gesellschaft. Mit dem Sachthema der „Migrationen“ und mit einem Blick weit über Europa hinaus, bis nach Amerika, Japan und ins südliche Afrika, wird der Übergang von einer eurozentrierten Mittelalterforschung zu einer transdisziplinären Mediävistik in globalen Zusammenhängen markiert
    • …
    corecore