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11.
Nutrient Biogeochemistry of the Coastal Zone 总被引：4，自引：0，他引：4
TD Jickells 《Science (New York, N.Y.)》1998,281(5374):217-221
The coastal seas are one of the most valuable and vulnerable of Earth's habitats. Significant inputs of nutrients to the coastal zone arrive via rivers, groundwater, and the atmosphere. Nutrient fluxes through these routes have been increased by human activity. In addition, the N:P:Si ratios of these inputs have been perturbed, and many coastal management practices exacerbate these perturbations. There is evidence of impacts arising from these changes (in phytoplankton numbers and relative species abundance, and deep-water oxygen declines) in areas of restricted water exchange. Elsewhere, the nutrient fluxes through the coastal zone appear to be still dominated by large inputs from the open ocean, and there is little evidence of anthropogenic perturbations. 相似文献
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Major health conditions in sheep contribute to substantial economic losses throughout the sheepmeat supply chain in Australia. A systematic review was undertaken to explore the measurable impact of six conditions: arthritis, sheep measles, pleurisy, pneumonia, grass seeds and rib fractures, on the production of lamb and mutton across the meat value chain. Peer‐reviewed scientific literature from three databases and non‐peer‐reviewed articles and reports from Australian government and non‐government websites were searched between 11 and 17 November 2019. Original articles, including studies conducted in Australia and New Zealand, that had measurable impacts on conditions of interest were included. The search yielded 16 articles and reports and were classified as producer impact and/or processor impact studies. Mortalities were quantified for pneumonia and arthritis, with pneumonia having the highest impact for producers. Grass seed infestation resulted in the highest impact on carcase and liveweight losses compared to arthritis and pneumonia. Arthritis had the highest trim weight losses for both lamb and mutton and the highest rate of carcase condemnation. Grass seed was the only condition where other impacts on the processor (chain speed and staff relocation to the boning room) were quantified. Although quantifiable production and processing losses were available for some conditions, this review has highlighted that limited quantifiable data based on scientifically sound research were not available for other conditions. The evidence for some conditions found in this review can be used to target future research activities and to further assist producers in making informed management decisions on prevention and control. 相似文献
13.
A 7-years-old Clydesdale mare was presented with severe abdominal distension and acute colic. Dilated large intestine was palpated per rectum and a ventral midline exploratory laparotomy was performed. A 180 degrees volvulus of the pelvic flexure was present, associated with an inelastic band of tissue connecting the mesocolon to the umbilicus. The band was ligated and transected, and the volvulus reduced. Postoperative complications included hyponatraemia, metabolic acidosis and laminitis. The possible aetiology of the mesocolic-umbilical band is discussed. 相似文献
14.
Skeletal ontogeny in extant archosaurians (crocodilians and birds) indicates that the morphology of the perinatal pelvic girdle is an indicator of overall developmental maturity [that is, altriciality (nestbound) versus precociality (mobile and relatively independent)]. Comparison of the skeletal anatomy of perinatal extant archosaurians and perinatal dinosaurs suggests that known dinosaur hatchlings were precocial. These data are consistent with the overall similarity in nesting behavior of dinosaurs and modern crocodilians. 相似文献
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EK Gee EC Firth PCH Morel PF Fennessy ND Grace TD Mogg 《New Zealand veterinary journal》2013,61(6):448-456
AIMS: To determine the influence of copper (Cu) supplementation by injection of mares in late gestation on the frequency and severity of osteochondrosis (OC) lesions in their foals at around 160 days of age. To determine if there was any influence of the concentration of Cu in the liver, growth rate, birthweight, weight at 160 days of age, fatness, sex, or year of birth of the foal on the frequency and severity of OC lesions. To determine the influence of dam's age, and sex and birthweight of the foal on the growth rate from birth to 160 days of age, and weight at 160 days of age. METHODS: Thirty-three Thoroughbred foals, born in two consecutive years, were weighed every 2 weeks from birth. The dams had been supplemented with parenteral Cu or saline during late gestation, and the supplementation regimens were different in each year. Foals had liver biopsies harvested at birth for determination of Cu concentration. Pasture samples were collected every 4–8 weeks for analysis of concentration of Cu and zinc (Zn). At 160 days of age, articular cartilage of long bones was examined. Gross lesions were counted and scored, then sawn and radiographed, and processed for histopathology. Lesions were given radiographic scores and histopathological scores. Maximum scores for each lesion were combined to give a total OC score for each joint and each foal. The fatness of 20 foals (10 each from Years 1 and 2) at 160 days of age was determined chemically. RESULTS: Supplementation of dams with Cu had no significant effect on the concentration of Cu in the liver of foals at birth, or on the frequency or severity of lesions in articular cartilage at 160 days of age. The Cu and Zn concentrations of pasture were similar in Years 1 and 2, and were lower than current recommendations. All foals in Year 2, and 9/10 foals in Year 1 had irregularities in cartilage that was confirmed histologically to be indicative of OC. The average number of lesions per foal was 4.7 (SD 1.1) and 5.7 (SD 1.1) in Years 1 and 2, respectively. However, the severity of the lesions was considered mild, and no foals showed any clinical evidence of OC while alive. The number of lesions in the tarsocrural (TC) joint and the TC OC score at 160 days were positively associated with average daily weight gain (ADG) in the previous 4 weeks (p=0.005 and p=0.001, respectively). There was no significant effect of sex, fatness, birth-weight, weight at 160 days of age, or year of birth of the foal on the frequency and severity of OC lesions. CONCLUSIONS: Many of the lesions classified as OC, using classification systems described by other authors, were likely to be normal variations of the process of endochondral ossification. Despite the high frequency of such lesions, they were considered to be of minor significance and none were clinically evident. The distribution of lesions was not typical, and most probably reflected the subtlety of the lesions. These results support the hypothesis that Cu is an over-emphasised factor in the aetiopathogenesis of OC. The relationship between subtle macroscopic lesions and lesions resulting in clinical signs of disease requires further investigation. 相似文献
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R. J. Kaitho N. N. Umunna I. V. Nsahlai S. Tamminga J. van Bruchem 《Agroforestry Systems》1997,39(2):161-173
The effect of different condensed tannins concentrations on protein metabolism from browse supplements was investigated in
a 90-day trial using sixty-six male Ethiopian Menz sheep. Teff straw (Eragrostis tef) was fed ad libitum (control diet), or
supplemented with 190 g dried leaves of six Sesbania sesban accessions with increasing levels of condensed tannin (S1, S2,
S3, S4, S5 and S6), lablab (Dolichos lablab), tagasaste (Chamaecytisus palmensis), leucaena (Leucaena leucocephala) and goetzei
(Sesbania goetzei) in a completely randomized block design. The condensed tannins were highest in goetzei; S6, S5 and leucaena,
intermediate in S4, S3, S2 and S1, and lowest in tagasaste and lablab. The supplemented animals had significantly (P < 0.05)
higher total dry matter and nitrogen (N) intake than the ones fed teff straw alone. The digestibility of N was lower for the
control diet than for any other treatment (P < 0.05). S1 and S2 supplemented diets had significantly higher (P < 0.05) N digestibilities
than all other diets. Faecal N, urinary N and urinary N per kg N excreted were significantly different (P < 0.0001) between
diets. With increasing tannin levels (among Sesbania accessions) there was a significant decrease (P < 0.05) in urinary N
(S1 > S2 > S3 > S4 > S5), and an increase (P < 0.05) in faecal N (S1 < S2 < S3 < S4 < S5). Supplementation increased faecal
N output significantly (P < 0.0001) as well as the N retention. Among the forage supplements, N retention was significantly
(P < 0.0001) lower in lablab-, tagasaste-, leucaena-, S4- and goetzei-supplemented diets, than for S1, S2, S5 and S6. Apparent
nitrogen digestibility was positively correlated (P < 0.001) with the supplement dry matter and crude protein (CP) degradation
after 24 h (r = 0.93 and r = 0.85, respectively), the CP content (r = 0.87), and was negatively correlated with acid detergent
fibre and neutral detergent fibre (r = –0.87 and –0.87, respectively). The CP degradability characteristics of the forages
differed (P < 0.001) in water solubility (93–470 g kg-1 CP), rate of degradation (2.58–9.73 %/h), lag phase (–1.36–13.37 h), and estimated escape protein (262–619 g kg-1 CP). With increasing tannin levels (among Sesbania accessions), there was a significant decrease (P < 0.0001) in the rate
of degradation (S1 > S2 > S3 > S4 > S5), and an increase in the estimated escape protein. The estimated rumen degradable protein
(supplements) varied from 482 to 744 g kg-1 CP, while intestine digestible protein and the undegradable protein varied from 140 to 314 g kg-1 CP, hence the browses can supply adequate levels of rumen degradable and bypass protein.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
18.
R. J. Kaitho N. N. Umunna I. V. Nsahlai S. Tamminga J. van Bruchem 《Agroforestry Systems》1997,39(2):145-159
The effect of tannins in browse supplements on intake, digestibility and live weight changes was evaluated using sixty-six
male Ethiopian Menz sheep in a 90-day trial. Teff straw (Eragrostis tef) was fed ad libitum (control diet), or supplemented
with 190 g dried leaves of six Sesbania sesban accessions with increasing levels of condensed tannin (S1, S2, S3, S4, S5 and
S6), lablab (Dolichos lablab), tagasaste (Chamaecytisus palmensis), leucaena (Leucaena leucocephala) and goetzei (Sesbania
goetzei), in a completely randomized block design. The condensed tannins were highest in goetzei, S6, S5 and leucaena, intermediate
in S4, S3, S2 and S1, and lowest in tagasaste and lablab. The forages differed significantly (P < 0.05) in their rates of
degradation and truly undegradable dry matter. Lablab had lower water solubility and higher (P < 0.05) truly undegradable
dry matter than the other browse supplements. With increasing tannin levels among Sesbania accessions, there was a significant
decrease (P < 0.05) in the rate of degradation. Animals supplemented with forage legumes with low condensed tannin levels
such as lablab, S1, S2, and S3 had a lower teff straw intake than those on the control diet. The converse was true for those
fed with the high tannin supplements such as S4, S5, S6 and goetzei. Supplementation significantly (P < 0.05) increased total
dry matter intake and live weight gains (LWG). The animals on the control diet lost weight (–1.9 g/kgW0.75, while the supplemented animals gained between 2.9 and 4.4 g/kgW0.75 daily. Leucaena supplementation promoted higher (P < 0.05) LWG than lablab, S1 and goetzei. With increasing tannin levels
among Sesbania accessions, there was an increase (S1 < S2 < S3 < S4) followed by a decrease (S6 > S5 > goetzei) in LWG. The
digestibilities of total DM and the supplements did not differ significantly (P < 0.05) between the diets, although the neutral
detergent fibre (NDF) digestibility decreased significantly (P < 0.05) with supplementation. The control diet had significantly
higher NDF digestibility than the leucaena, S3, S4, S5 and S6 supplemented diets. Results have beneficial attributes at low
levels in ruminants. Condensed tannins confer important advantages in ruminant nutrition with respect to the prevention of
excessive degradation of protein in the rumen.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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R. J. Kaitho N. N. Umunna I. V. Nsahlai S. Tamminga J. Van Bruchem J. Hanson M. Van De Wouw 《Agroforestry Systems》1996,33(3):249-261
The potential forage value and appropriate length of study on intake and relative palatability ranking of 40 multipurpose tree species (MPTs) were determined using 24 sheep blocked on live weight and age. As the MPTs had different dry matter contents, intakes were also expressed as a ratio of quantity offered (Ai/Di). Using daily Eragrostis tef straw offer (TD) and intake (T), relative palatability indices were calculated as Ri = (Ai/Di)/(Ti/TDi). There was a significant (P < 0.0001) decrease in correlation of intake measured in day 1 and subsequent days (r = 0.88, 0.81 and 0.79 for days 2–4, days 5–8 and days 9–12, respectively). A similar trend was observed on corresponding palatability indices. Individual animal preference and blocking did not affect intake and palatability indices significantly (P > 0.05), however significant (P < 0.0001) tree species differences were observed. Results on linear regression, correlation coefficients, palatability ranking and standard errors of means (adjusted palatability indices) indicate that, if palatability is done to predict long-term intake of MPTs, at least 5 days are appropriate in palatability assessment for sheep. Using mean palatability index (days 2–12), the MPTs were grouped into four clusters. The MPTs such as Leucaena leucocephala and Sesbania sesban which are known to have good nutritive value had high palatability. In the same classification group, there were less known species such as Acacia venosa, A. persiciflora, A. melanoxylon, A. hockii, A. polycantha, Tamarindus indica, Chamaecytisus palmensis, Tipuana tipu, Indigofera arrecta and Atriplex nummularia. Flemingia macrophylla, Erythrina abyssinica, Acacia salicina, Acacia coriacea, Albizia schimperiana, Ceratonia siliqua, Casuarina glauca and Erythrina burana had poor palatability. These species seem to have little forage value for animals with short-term adaptation periods. Gliricida sepium and Calliandra calothyrsus although currently being used by farmers had a medium palatability ranking. 相似文献