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Cosgrove R 《Science (New York, N.Y.)》1989,243(4899):1706-1708
Basal dates of 30,420 years before present (BP) from a limestone cave in the Florentine River valley and 30,840 BP from a sandstone rockshelter in the Shannon River valley on the edge of the central Tasmanian highlands indicate colonization of Tasmania 8,000 years earlier than previously thought. These data indicate that people arrived before the Bassian Bridge was exposed about 23,000 years ago and support evidence that Tasmania and Australia may have been connected intermittently during the past 50,000 years. The dates support earlier suggestions that the Tasmanian inland was an important focus for systematic occupation and exploitation by human groups and dispel a belief that the Aboriginal economy 30,000 years ago was based on littoral, lacustral, and riverine resources. The absence of megafauna at both sites points to their extinction by 30,000 years ago in Tasmania. The people inhabiting Tasmania at this time, together with those at Monte Verde in Chile, were the most southerly humans on Earth. 相似文献
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Thirty-three of the 44 mares on a Thoroughbred stud in New South Wales aborted or lost foals within one day of birth. Gross pathological and histological changes were in keeping with Equid herpesvirus I (EHV-1) abortion. In the six foals that underwent virological examination, EHV was isolated and typed as EHV-1 by restriction endonuclease analysis. EHV-1 abortion had not occurred previously on this stud and the source of the infection was not identified. 相似文献
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CJ MORROW † IG BELL† SB WALKER§ PF MARKHAM† BH THORP¶ KG WHITHEAR† 《Australian veterinary journal》1990,67(4):121-124
This report describes the first isolations of Mycoplasma synoviae from the synovial sheaths and joints of commercial chickens affected with synovitis in Australia. Over 4 years 3 separate outbreaks were investigated in which up to 20% of birds exhibited clinical signs of poor growth and "hot foot" syndrome (swollen inflamed footpads). Once an outbreak occurred, chronic infection of the farm usually ensued. Grossly the hocks and footpads were swollen by a purulent exudate and associated inflammatory changes with histological features of a severe acute synovitis. Seroconversion of the flocks occurred at the time of the development of lesions. M. synoviae specific antibodies were demonstrated by ELISA in the joint fluid of affected birds. It is concluded that the cases described are similar to avian infectious synovitis syndrome caused by M. synoviae previously described overseas. 相似文献
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J. Hill D.F. Chapman G.P. Cosgrove A.J. Parsons 《Strength and Conditioning Journal》2009,62(5):418-427
When offered a free choice between different forage species presented in a pasture association, ruminants will choose a mixed diet, even when one dietary component could meet all of their nutritional needs. Thus, preference and selection cannot be explained simply by the common measures of species nutritive or feeding value. The question then arises, what is the nutritional basis of the dietary choices that animals make? The objective of this paper is to review the role of synchronization of forage composition factors and nutrient release patterns on the processes controlling preference in grazing ruminants. The satiety theory is used as a model system to explore outcomes of changing the physico-chemical attributes of forages on grazing behavior of sheep and cattle. The review will examine further the biological basis for the alteration in meal pattern, duration and extent in ruminants offered clover only (relatively high rumen degradable protein content) compared to animals eating only grass (with relatively low rumen degradable protein content), or a mixture of grass and clover. One theory that has been proposed to explain the induction of satiety in grazing ruminants is the rate of release of ammonia from the soluble protein fraction of the forage, and subsequent uptake in the blood. By mixing grass with the clover, the animal is able to increase the duration of the meal potentially reflecting a “better” dietary balance of energy to soluble protein that controls the rate of accumulation of ammonia in rumen fluid. This concept is evaluated in light of recent data from in vitro studies examining digestive efficiency. From this analysis, it is clear that direct, real-time information on the relationships between forage physico-chemical factors, rumen condition, meal initiation and cessation, and dietary switching is needed to further develop propositions about the control of dietary choices of grazing ruminants. 相似文献
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OBJECTIVE: To evaluate the impact of the disaggregation of composite foods on intake estimates of meat and individual meat categories and on the contribution of meat to nutrient intakes in Irish adults. DESIGN: Data were analysed from the North/South Ireland Food Consumption Survey, which used a 7-day food diary to estimate food intake. Of 742 food codes that contained meat, 320 were codes for meat consumed as an individual portion and 422 were composite foods and were disaggregated to estimate the meat content. SUBJECTS: A nationally representative sample of 475 men and 483 women (not pregnant or lactating) from the Republic of Ireland aged 18-64 years. RESULTS: The mean intake of meat was 134 g day(-1) in consumers (98.5%) and men (168 g day(-1)) consumed significantly more (P<0.001) than women (102 g day(-1)). Mean intakes of meat were higher in subjects with manual skilled occupations (P<0.01) and lower in those with third-level educational qualifications (P<0.05). Without disaggregating meat from composite foods, meat intake was overestimated by 43% (57 g day(-1)) and varied widely by meat category. Meat disaggregated from composite foods contributed 25% of meat intake. The contribution meat made to nutrient intakes ranged from 29% for protein, vitamin B12, zinc and niacin to 20% for vitamin D, 16% for vitamin B6, 15% for thiamine and 14% for iron. CONCLUSIONS: Failure to disaggregate meat from composite foods substantially overestimates meat intake, with a large variation between meat categories. This has important implications for estimates of meat intakes in nutritional epidemiological studies and for food safety purposes. 相似文献
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Peridotite xenoliths from the Cascade arc in the United States and in the Japan arc have neodymium and osmium isotopic compositions that are consistent with addition of 5 to 15 percent of subducted material to the present-day depleted mantle. These observations suggest that osmium can be partitioned into oxidized and chlorine-rich slab-derived fluids or melts. These results place new constraints on the behavior of osmium (and possibly other platinum group elements) during subduction of oceanic crust by showing that osmium can be transported into the mantle wedge. 相似文献
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MR Luz CC de Holanda JJ Pereira PMC Freitas AEP Salgado J Di Giorgio Giannotti SB de Oliveira NS Teixeira CR de Freitas Guaitolini 《Reproduction in domestic animals》2011,46(4):724-727
The embryonic collection techniques in dogs present a vast methodological variation and low recovery rates. The objectives were to compare and describe two techniques as to the recovery of canine embryos, on the 12th day after the first mating or artificial insemination. Embryos were recovered through uterine horn flushing in vivo, before performing the ovariohysterectomy (OHE) (Group 1; n = 9) or ex vivo, immediately after the OHE (Group 2; n = 9). In total, 43 and 47 embryonic structures were recovered in Groups 1 and 2, respectively. There was no significant difference (p > 0.05) between groups on recovery rates (72.8% and 81.0%, respectively). We inferred that both in vivo and ex vivo techniques allow a high rate of embryonic recovery; in the collection technique prior to the OHE, it is essential to carefully handle the reproductive system during the trans‐surgical period and that the 12th day (D12) after the first mating/artificial insemination is an efficient option for the high recovery rate of morulae and blastocysts. 相似文献
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Two experiments were conducted to determine mechanisms mediating effects of nutritional manipulation before and after mating on embryonic survival in pigs. Experiment 1 studied the mechanisms by which continued high feeding levels after mating result in differences in plasma progesterone during early pregnancy. Gilts fed 2.0 times maintenance energy requirements either remained on this high level or feed was reduced to 1.5 times maintenance immediately after mating. Ovarian, oviductal, and jugular vein progesterone concentrations were determined 72 h after onset of estrus, and samples taken every 4 h were used to determine LH and progesterone during the periestrous period. Treatment did not affect peripheral progesterone concentrations, the timing or rate of rise of progesterone, or progesterone in ovarian, oviductal, or jugular veins at the time of surgery. Time after the LH peak was highly correlated (P = 0.0001) with jugular progesterone concentrations, but not with those in oviductal and ovarian veins, suggesting that responses in the reproductive tract mediated by peripheral progesterone concentrations will be temporally different to effects within tissues supplied by the ovarian and oviductal vasculature. Experiment 2 studied mechanisms mediating nutritional manipulation in the preovulatory period on postovulatory reproductive function, using feed restriction during the first (RH) or second (HR) week of the estrous cycle. Surgeries were performed 12 to 20 h after ovulation, and fertilized oocytes were cultured for 144 h in vitro. Ovulation rate was not affected by previous nutritional regimen. Fertilization rate was higher (P = 0.056) in RH vs HR gilts, but development of cultured oocytes was not affected by treatment. There were no treatment differences in peripheral or oviductal plasma progesterone, estradiol, or insulin-like growth factor-I (IGF-I) at surgery, or in porcine oviductal secretory protein abundance and IGF-I concentrations in oviduct flushings, but treatment affected total protein concentration (P = 0.002). These results indicate that either previous nutritional treatment does not affect the early developmental competence of fertilized oocytes in vitro or differences in developmental competence of oocytes are not expressed up to the early blastocyst stage. However, the lack of an effect of previous nutrition on steroids in the local oviductal circulation may also be related to the lack of effects on oviductal function and embryonic development. 相似文献