133 research outputs found
Potentials to differentiate milk composition by different feeding strategies
To investigate the effect of the dietary intake of the cow on milk composition, bulk-tank milk was collected on 5 occasions from conventional (n = 15) and organic (n = 10) farms in Denmark and on 4 occasions from low-input nonorganic farms in the United Kingdom, along with management and production parameters. Production of milk based on feeding a high intake of cereals, pasture, and grass silage resulted in milk with a high concentration of α-linolenic acid (9.4 ± 0.2 mg/ kg of fatty acids), polyunsaturated fatty acids (3.66 ± 0.07 mg/kg of fatty acids), and natural stereoisomer of α-tocopherol (RRR-α-tocopherol, 18.6 ± 0.5 mg/kg of milk fat). A milk production system using a high proportion of maize silage, by-products, and commercial concentrate mix was associated with milk with high concentrations of linoleic acid (LA; 19.7 ± 0.4 g/kg of fatty acids), monounsaturated fatty acids (27.5 ± 0.3 mg/kg of fatty acids), and a high ratio between LA and α-linolenic acid (4.7 ± 0.2). Comparing these 2 production systems with a very extensive nonorganic milk production system relying on pasture as almost the sole feed (95 ± 4% dry matter intake), it was found that the concentrations of conjugated LA (cis-9,trans-11; 17.5 ± 0.7 g/kg of fatty acids), trans-11-vaccenic acid (37 ± 2 g/kg of fatty acids), and monounsaturated fatty acids (30.4 ± 0.6 g/kg of fatty acids) were higher in the extensively produced milk together with the concentration of antioxidants; total α-tocopherol (32.0 ± 0.8 mg/kg of milk fat), RRR-α-tocopherol (30.2 ± 0.8 mg/kg of milk fat), and β-carotene (9.3 ± 0.5 mg/kg of milk fat) compared with the organic and conventional milk.
Moreover, the concentration of LA (9.2 ± 0.7 g/kg of fatty acids) in milk from the extensive milk production system was found to approach the recommended unity ratio between n-6 and n-3, although extensive milk production also resulted in a lower daily milk yield
Content of fatty acids, vitamin E and carotenoids in milk and herbage as affected by sward composition and period of grazing
The quality of organic milk is affected by feed composition, and especially the high use of legumes has been identified as the reason for high levels of polyunsaturated fatty acids, carotenoids and tocopherols in organic milk.
Four different pastures composed of mainly white clover (WCL), red clover (RCL), lucerne (LUC) or chicory (CIK), respectively, were established to investigate the influence of sward composition on the milk quality of grazing cows. On three occasions during the grazing period (May, June and August), groups of 12 Holstein cows were grazing the pastures for two weeks. About 70% of the daily dry matter intake was pasture, and the remaining dry matter intake was a mixture of oats, hay and minerals (82%, 16%, 2%, respectively). The swards were sampled, and their feed quality as well as their composition of carotenoids, tocopherols and fatty acids was analysed. On each occasion, milk was sampled after two weeks of grazing, and the content of tocopherols and carotenoids as well as the composition of fatty acids was analysed.
The overall feed quality expressed as IVOMD (in vitro organic matter disappearance) and NDF (neutral detergent fibre) was affected by period and to a lesser extent by forage type. The content of carotenoids was higher in RCL compared to the other forages, while no effect of period was observed. Alpha-tocopherol was neither affected by period nor by forage type. Fatty acid content, in particular content of linolenic acid, decreased during the grazing period, and it was highest in RCL, intermediate in CIK and lowest in WCL and LUC.
Milk yield was neither affected by period nor by forage type. Milk fatty acid composition and content of alpha-tocopherol and carotenoids showed minor differences between forage types and sampling occasions. However, multivariate analysis of these data showed grouping according to sampling occasion, but no clear grouping according to forage types.
Despite the differences in composition of forage and in composition of milk, it was not possible to predict milk content of specific fatty acids, carotenoids or tocopherols from the feed content of these compounds. This was partly explained by differences in feed digestibility.
Comparison of the milk with previous studies showed higher concentrations of beneficiary compounds such as linolenic acid (12 mg/g fatty acids), conjugated linoleic acid (13 mg/g fatty acids), carotenoids (6 µg/g milk fat) and alpha-tocopherol (21 µg/g milk fat), and it was concluded that all the forages tested could be used in production of a milk with such properties
Effect of grazing white clover pasture on milk composition of Holstein and Jersey cows
Because of its high saturated fatty acid (FA) content milk fat is considered hypercholesterolemic. Intake of unsaturated FA (UFA) reduces the plasma cholesterol concentrations. Especially conjugated linoleic acids (CLA) have shown positive effects on cardiovascular diseases, prevention of cancer and obesity. The aim of our project is to investigate how grazing can enhance the content of these beneficiary FA in milk. For bith types of cow races we observed no direct effect of increased grazing in the diet on the short chain FA (SCFA) content in milk, implying that the de novo synthesis of these FA remained unaffected. Regarding the content of CLA c9,t11 there was a strong positive effect on Holstein milk (R2 = 0,88), but almost none on Jersey milk when the percentage of grazing increases in the diet, thus suggesting that the mammary gland D9-desaturase acitivities of these two cow races react differently to increasing pasture grazing
Animal production from dairy breed steers at extensively managed grasslands in riverside areas
In Denmark, some of the grassland in marginal areas are abandoned for agricultural use - grassland that it is of interest to preserve because they have a high actural or potential natural quality when managed with extensive grazing or cuttting. A comparison was carried out for three years on sward productivity and weight gain of the steers at two grazing intensities on wet semi-natural grassland. The daily weight gain of steers was on average 667 g at low and 477 g at high grazing intensity. Sward grass yield as dry matter (DM) production was on average 4.1 Mg DM ha4, with no significant difference sound between the two gazing intensities. In vitroorganic matter digestibility (IVOMD) was rexpectigely 56.4 and 53.0 at high and low grazing intensity. It is concluded that the variatin in sward productivity and sward composition between years and grazing intensities was reflected in the production of the steers
Kysttorsk og miljø. Dataserier og verktøy for studier av miljøets betydning for bestandssituasjonen
Årsliste 2005Bestanden av kysttorsk har gått sammenhengende tilbake fra 1994. Overbeskatning anses som en hovedårsak. Kysttorsk består trolig av en mosaikk av ulike delbestander, og trusselfaktorene kan tenkes å variere mellom ulike områder. Denne rapporten gir en kortfattet oversikt over miljømessige trusselfaktorer for norsk kysttorsk, og peker på noen viktige oppgaver for å kartlegge årsaker, omfang av trusler mot kysttorskens habitat. Lange dataserier fra Kystovervåkingen kan danne grunnlag for nasjonale, regionale og lokale trendanalyser i tidsrommet før og under kysttorskens tilbakegang. Oversikt over miljøgifter knyttet til sedimenter kan utgjøre lokale trusselfaktorer. Det er også påvist omfattende skader på torskens oppvekst-habitat, både langs Skagrarrakkysten og i våre fire nordligste fylker. På Skagerrakkysten og lokalt i ferskvannspåvirkete fjorder på Vestlandet, kan estuarine blandsoner med tilførsler av forsuret, aluminiumsholdig vann ha spilt en rolle for overlevelse av ungstadier av torsk. Informasjon om kysttorskens gyteområder foreligger i en rekke ulike kilder, primært Fiskeridirektoratet, lokale kystsoneplaner og avgrensete pilotprosjekter av vitenskapelig karakter.NIV
Does anaesthesia cause postoperative cognitive dysfunction? A randomised study of regional versus general anaesthesia in 438 elderly patients
Keywords:anesthesia;cognitive function;complications;postoperative period;regional anesthesia;surgery Background: Postoperative cognitive dysfunction (POCD) is a common complication after cardiac and major non-cardiac surgery with general anaesthesia in the elderly. We hypothesized that the incidence of POCD would be less with regional anaesthesia rather than general. Methods: We included patients aged over 60 years undergoing major non-cardiac surgery. After giving written informed consent, patients were randomly allocated to general or regional anaesthesia. Cognitive function was assessed using four neuropsychological tests undertaken preoperatively and at 7 days and 3 months postoperatively. POCD was defined as a combined Z score >1.96 or a Z score >1.96 in two or more test parameters. Results: At 7 days, POCD was found in 37/188 patients (19.7%, [14.3–26.1%]) after general anaesthesia and in 22/176 (12.5%, [8.0–18.3%]) after regional anaesthesia, P = 0.06. After 3 months, POCD was present in 25/175 patients (14.3%, [9.5–20.4%]) after general anaesthesia vs. 23/165 (13.9%, [9.0–20.2%]) after regional anaesthesia, P = 0.93. The incidence of POCD after 1 week was significantly greater after general anaesthesia when we excluded patients who did not receive the allocated anaesthetic: 33/156 (21.2%[15.0–28.4%]) vs. 20/158 (12.7%[7.9–18.9%]) (P = 0.04). Mortality was significantly greater after general anaesthesia (4/217 vs. 0/211 (P <0.05)). Conclusion: No significant difference was found in the incidence of cognitive dysfunction 3 months after either general or regional anaesthesia in elderly patients. Thus, there seems to be no causative relationship between general anaesthesia and long-term POCD. Regional anaesthesia may decrease mortality and the incidence of POCD early after surgery
Monitoring boreal forest biomass and carbon storage change by integrating airborne laser scanning, biometry and eddy covariance data
AbstractThis study presents a comparison and integration of three methods commonly used to estimate the amount of forest ecosystem carbon (C) available for storage. In particular, we examine the representation of living above- and below-ground biomass change (net accumulation) using plot-level biometry and repeat airborne laser scanning (ALS) of three dimensional forest plot structure. These are compared with cumulative net CO2 fluxes (net ecosystem production, NEP) from eddy covariance (EC) over a six-year period within a jack pine chronosequence of four stands (~94, 30, 14 and 3years since establishment from 2005) located in central Saskatchewan, Canada. Combining the results of the two methods yield valuable observations on the partitioning of C within ecosystems. Subtracting total living biomass C accumulation from NEP results in a residual that represents change in soil and litter C storage. When plotted against time for the stands investigated, the curve produced is analogous to the soil C dynamics described in Covington (1981). Here, ALS biomass accumulation exceeds EC-based NEP measured in young stands, with the residual declining with age as stands regenerate and litter decomposition stabilizes. During the 50–70year age-period, NEP and live biomass accumulation come into balance, with the soil and litter pools of stands 70–100years post-disturbance becoming a net store of C. Biomass accumulation was greater in 2008–2011 compared to 2005–2008, with the smallest increase in the 94-year-old “old jack pine” stand and greatest in the 14-year-old “harvested jack pine 1994” stand, with values of 1.4 (±3.2) tCha−1 and 12.0 (±1.6) tCha−1, respectively. The efficiency with which CO2 was stored in accumulated biomass was lowest in the youngest and oldest stands, but peaked during rapid regeneration following harvest (14-year-old stand). The analysis highlights that the primary source of uncertainty in the data integration workflow is in the calculation of biomass expansion factors, and this aspect of the workflow needs to be implemented with caution to avoid large error propagations. We suggest that the adoption of integrated ALS, in situ and atmospheric flux monitoring frameworks is needed to improve spatio-temporal partitioning of C balance components at sub-decadal scale within rapidly changing forest ecosystems and for use in national carbon accounting programs
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