192 research outputs found

    South Dakota Retained Ownership Demonstration

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    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

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    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

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    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

    Jackdaw nestlings can discriminate between conspecific calls but do not beg specifically to their parents

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    This is a pre-copyedited, author-produced PDF of an article accepted for publication in Behavioral Ecology following peer review. The definitive publisher-authenticated version Lies Zandberg, Jolle W. Jolles, Neeltje J. Boogert, and Alex Thornton Jackdaw nestlings can discriminate between conspecific calls but do not beg specifically to their parents Behavioral Ecology (2014) 25 (3): 565-573 first published online February 28, 2014 doi:10.1093/beheco/aru026 is available online at: http://intl-beheco.oxfordjournals.org/content/25/3/565.The ability to recognize other individuals may provide substantial benefits to young birds, allowing them to target their begging efforts appropriately, follow caregivers after fledging, and establish social relationships later in life. Individual recognition using vocal cues is likely to play an important role in the social lives of birds such as corvids that provision their young postfledging and form stable social bonds, but the early development of vocal recognition has received little attention. We used playback experiments on jackdaws, a colonial corvid species, to test whether nestlings begin to recognize their parents’ calls before fledging. Although the food calls made by adults when provisioning nestlings were individually distinctive, nestlings did not beg preferentially to their parents’ calls. Ten-day-old nestlings not only responded equally to the calls of their parents, neighboring jackdaws whose calls they were likely to overhear regularly and unfamiliar jackdaws from distant nest boxes, but also to the calls of rooks, a sympatric corvid species. Responses to rooks declined substantially with age, but 20- and 28-day-old nestlings were still equally likely to produce vocal and postural begging responses to parental and nonparental calls. This is unlikely to be due to an inability to discriminate between calls, as older nestlings did respond more quickly and with greater vocal intensity to familiar calls, with some indication of discrimination between parents and neighbors. These results suggest that jackdaws develop the perceptual and cognitive resources to discriminate between conspecific calls before fledging but may not benefit from selective begging responses

    The CLAS12 Spectrometer at Jefferson Laboratory

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    The CEBAF Large Acceptance Spectrometer for operation at 12 GeV beam energy (CLAS12) in Hall B at Jefferson Laboratory is used to study electro-induced nuclear and hadronic reactions. This spectrometer provides efficient detection of charged and neutral particles over a large fraction of the full solid angle. CLAS12 has been part of the energy-doubling project of Jefferson Lab's Continuous Electron Beam Accelerator Facility, funded by the United States Department of Energy. An international collaboration of 48 institutions contributed to the design and construction of detector hardware, developed the software packages for the simulation of complex event patterns, and commissioned the detector systems. CLAS12 is based on a dual-magnet system with a superconducting torus magnet that provides a largely azimuthal field distribution that covers the forward polar angle range up to 35∘, and a solenoid magnet and detector covering the polar angles from 35° to 125° with full azimuthal coverage. Trajectory reconstruction in the forward direction using drift chambers and in the central direction using a vertex tracker results in momentum resolutions of <1% and <3%, respectively. Cherenkov counters, time-of-flight scintillators, and electromagnetic calorimeters provide good particle identification. Fast triggering and high data-acquisition rates allow operation at a luminosity of 1035 cm−2s−1. These capabilities are being used in a broad program to study the structure and interactions of nucleons, nuclei, and mesons, using polarized and unpolarized electron beams and targets for beam energies up to 11 GeV. This paper gives a general description of the design, construction, and performance of CLAS12

    The importance of the altricial – precocial spectrum for social complexity in mammals and birds:A review

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    Various types of long-term stable relationships that individuals uphold, including cooperation and competition between group members, define social complexity in vertebrates. Numerous life history, physiological and cognitive traits have been shown to affect, or to be affected by, such social relationships. As such, differences in developmental modes, i.e. the ‘altricial-precocial’ spectrum, may play an important role in understanding the interspecific variation in occurrence of social interactions, but to what extent this is the case is unclear because the role of the developmental mode has not been studied directly in across-species studies of sociality. In other words, although there are studies on the effects of developmental mode on brain size, on the effects of brain size on cognition, and on the effects of cognition on social complexity, there are no studies directly investigating the link between developmental mode and social complexity. This is surprising because developmental differences play a significant role in the evolution of, for example, brain size, which is in turn considered an essential building block with respect to social complexity. Here, we compiled an overview of studies on various aspects of the complexity of social systems in altricial and precocial mammals and birds. Although systematic studies are scarce and do not allow for a quantitative comparison, we show that several forms of social relationships and cognitive abilities occur in species along the entire developmental spectrum. Based on the existing evidence it seems that differences in developmental modes play a minor role in whether or not individuals or species are able to meet the cognitive capabilities and requirements for maintaining complex social relationships. Given the scarcity of comparative studies and potential subtle differences, however, we suggest that future studies should consider developmental differences to determine whether our finding is general or whether some of the vast variation in social complexity across species can be explained by developmental mode. This would allow a more detailed assessment of the relative importance of developmental mode in the evolution of vertebrate social systems

    Sex differences in razorbill Alca torda parent–offspring vocal recognition

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    We investigated differences in parent–offspring vocal recognition between males and females in a natural population of razorbills Alca torda, a long-lived and highly social species of auk (Family: Alcidae). Razorbills provide biparental care to their chicks while at the nest site, after which the male is the sole caregiver for an additional period at sea. Parent–offspring recognition in razorbills is most challenging once the chick becomes mobile, leaves the nest site and goes to sea with the male parent. It is during this period when selection pressure acting on recognition behaviour is expected to be strongest. As a result, we predicted that parent–offspring recognition would be better developed in the male parent, that is, show a paternal bias. To test this prediction we used vocal playback experiments conducted on breeding razorbills at the Gannet Islands, Labrador, Canada. We found (1) most positive responses to playbacks (vocal and phonotactic)occurred close to fledging, (2) males responded more to calls from their chicks than to calls from strange chicks, (3) females responded indifferently to calls from their own or strange chicks and (4) chicks responded more to calls from their male parent than to calls from other adult males. The results provide clear evidence of mutual vocal recognition between the male parent and the chick but not between the female parent and the chick, supporting the prediction that parent–offspring recognition is male biased in this species. Such a bias could have important social implications for a variety of behavioural and basic life history traits such as cooperation and sex-biased dispersal
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