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71.
Stephanie M Nowacek Randall S Wells Edward C.G Owen Richard O Flamm 《Biological conservation》2004,119(4):517-523
Florida manatees inhabit shallow coastal and estuarine waters of the southeast US, a range that brings them into frequent contact with vessels. More than 30% of documented annual mortalities are attributed to vessel collisions, and most living animals bear the scars of multiple, non-lethal encounters. To document the behavior of manatees in the presence of vessels, we recorded their movements with an overhead video system. We scored six aspects of behavior during 170 vessel approaches, and compared their behavior with 187 control segments when no boats were present. Manatees in shallow waters and at the edge of the channel responded to approaches by orienting towards the nearest deep water, a boat channel, and increasing their swimming speed. Close boat approaches and shallow water depths exacerbated these responses. Our results indicate that manatees detect and respond to approaching vessels with an apparent flight response, a response which includes movement towards deeper water. If given sufficient time, i.e., approached or passed slowly, the manatees may then be able to reach deeper water and safe depths. 相似文献
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The clinical details of two cases of equine primary gastric impaction are described and the syndromes of gastric impaction and dilatation are discussed. Both cases of gastric impaction were successfully treated by gastrotomy and evacuation of the gastric contents. 相似文献
74.
L N Owen 《The Journal of small animal practice》1969,10(10):605-613
A review of recent advances made in the study of lymphosarcoma in man and animals has been made. Some aspects of leukaemia are also described. 相似文献
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Transplantation of dog neoplasms into the mouse mutant Nude 总被引:2,自引:0,他引:2
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J.B Owen 《Livestock Production Science》1984,11(3):269-285
The complete diet system involves processing the ingredients of cattle diets into a well-mixed blend to which the cattle are given free access. Mixing the diet in this way has often been shown to increase daily intake and to increase the solids content of the milk of cows, although total milk production may not be increased.The necessity for varying forage:concentrate ratio with stage of production in cows is examined in relation to complete diets and for the feeding of separate ingredients. The evidence so far suggests that, where the basic forage is of good quality, there seems little justification for varying diet composition with the consequent necessity for grouping the cows.Specifications are outlined for computer formulation of complete diets showing the main aspects which require further clarification, notably roughage characteristics, protein degradability, amino acid composition of rumen undegradable protein and intake characteristics of mixed feeds.Advantages for complete diets appear to be simplicity of management and full mechanisation, coupled with economy of feeding space, safety and flexibility for inclusion of a wide range of ingredients. Disadvantages, as with most mechanisation, include high capital cost and risks of mechanical breakdown.Future developments envisaged include the use of low forage, straw-based diets for arid areas where the provision of conventional forage is costly. 相似文献
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