Literatura académica sobre el tema "Saltbush"
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Artículos de revistas sobre el tema "Saltbush"
1
Norman, Hayley C., Colby Freind, David G. Masters, Allan J. Rintoul, Robyn A. Dynes y Ian H. Williams. "Variation within and between two saltbush species in plant composition and subsequent selection by sheep". Australian Journal of Agricultural Research 55, n.º 9 (2004): 999. http://dx.doi.org/10.1071/ar04031.
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This work examines nutritive value and preference by sheep of 2 saltbush species, river saltbush (Atriplex amnicola) and old man saltbush (Atriplex nummularia). Both species are woody perennials that are native to Australia and used in commercial grazing systems. The hypothesis for this study was that sheep will graze saltbushes with higher nutritive value and lower secondary compounds in preference to bushes with lower nutritive value and higher secondary compounds. This was expected to be found both within and between the old man and river saltbush species. To test the hypothesis, 10-month-old Merino ewes grazed a 10-ha plot containing a mixture of old man and river saltbush in approximately equal proportions. Within the plot, and prior to grazing, 20 bushes of each species were pegged for identification and samples of edible plant material collected for analysis. Each week during the grazing period the bushes were photographed for assessment of preference. Sheep preferred river saltbush to old man saltbush and also showed some preferences for specific bushes within each species. Differences in digestibility of dry matter and organic matter, crude protein, ash, oxalates, and nitrates were not clearly associated with differences in preference. Although the reasons for preferences were not demonstrated, the analysis of the plant material did indicate that the content of total ash and oxalates was at levels likely to depress voluntary feed intake.
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Fancote, C. R., H. C. Norman, I. H. Williams y D. G. Masters. "Cattle performed as well as sheep when grazing a river saltbush (Atriplex amnicola)-based pasture". Animal Production Science 49, n.º 11 (2009): 998. http://dx.doi.org/10.1071/ea08230.
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In Mediterranean-type climates, saltbush grown on saline land offers producers valuable feed during the autumn feed gap. Saltbush has high crude protein concentrations, moderate to low energy concentrations and accumulates very high concentrations of soluble salt. As ruminants cannot store quantities of salt, intake of saltbush is limited by the individuals’ ability to excrete salt. The aim of this 6-week study was to compare the relative performance, diet selection and urine concentrating ability of mature sheep and cattle grazing a young stand of river saltbush (Atriplex amnicola) with a volunteer annual understorey, consisting of senesced and germinating annual grasses. We measured liveweight and condition score of 30 mature Merino wethers and 15 mature Hereford-cross cows grazing the same saltbush stand, with a volunteer understorey of predominantly annual grasses, for 6 weeks during late autumn. Saltbush intake and diet selection were estimated at the same time using sodium (Na) : creatinine ratios in urine and carbon isotope ratios in faeces. During the first 3 weeks of grazing, the data indicated that cattle significantly outperformed sheep with a 15% increase in liveweight compared with sheep with an average increase of 4%. It is possible that some of this difference may be associated with different rates of loss of digesta associated with restricted access to food in the 2 h before weighing. No differences were found between the proportion of plants with a C4 photosynthetic pathway (saltbushes) in the diets selected by sheep and cattle for the majority of grazing. The specific gravity and Na concentration of urine was similar across livestock species. While this provided no indication of a difference in ability to concentrate or excrete Na, sheep did have a consistently higher Na : creatinine ratio in urine. The higher ratio is consistent with more efficient Na excretion and this may be significant when the species graze saltbush without low salt supplement or if water is restricted. Historically, it has been thought that cattle would not perform as well as sheep when grazing saltbush, but under the conditions of this study, when feed on offer is not limiting dry matter intake and fresh water is available, cattle are able to utilise this out of season feed source as well as, or possibly better than, sheep.
3
Barrett-Lennard, E. G. y C. V. Malcolm. "Increased concentrations of chloride beneath stands of saltbushes (Atriplex species) suggest substantial use of groundwater". Australian Journal of Experimental Agriculture 39, n.º 8 (1999): 949. http://dx.doi.org/10.1071/ea99068.
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Summary. This paper examines the accumulation of soil chloride and the increase in electrical conductivity of the groundwater beneath stands of saltbushes (Atriplex species) in a plant spacing trial conducted near Kellerberrin in Western Australia. The trial had a randomised block design with 5 plant spacings (1 by 1 m, 1 by 2 m, 2 by 2 m, 2 by 3 m, and 3 by 3 m), 5 saltbush species (Atriplex undulata D. Dietr., A. amnicola Paul G. Wilson, A. vesicaria Heward ex Benth., A. paludosa R. Br. and A. bunburyana F. Muell.) and 3 replicate plots (each consisting of 25 plants in 5 by 5 array). The saline groundwater at the site was between 0.5 and 1.2 m below the surface for the duration of the experiment. Over a 2-year period there was a substantial increase in soil chloride concentration beneath the saltbushes. These increases were proportional to saltbush ‘leaf density’ (weight per unit soil surface area) and inversely proportional to the initial concentration of chloride in the soil. There was a substantial increase in the electrical conductivity of the groundwater which was also proportional to ‘leaf density’. It is argued that the increases in soil salinity and groundwater electrical conductivity were primarily due to the use of groundwater by the saltbush stands. Salt accumulation data suggest that about 60–100 mm of groundwater was used (transpiration and evaporation) over the 2 years. These results are discussed in terms of the ability of saltbushes to lower local watertables, thereby making saline soils better suited to the growth of superior annual pasture species.
4
Chadwick, M. A., P. E. Vercoe, I. H. Williams y D. K. Revell. "Programming sheep production on saltbush: adaptations of offspring from ewes that consumed high amounts of salt during pregnancy and early lactation". Animal Production Science 49, n.º 4 (2009): 311. http://dx.doi.org/10.1071/ea08234.
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We investigated if feeding a high salt diet (pellet containing 14% NaCl) or saltbush (Atriplex nummularia) to ewes between day 60 of gestation and day 21 of lactation would allow their offspring to gain more weight, and produce more wool, when grazing saltbush as adults compared to offspring from ewes that were fed a control diet (2% NaCl) or grazed pasture. At 10 months of age, offspring grazed saltbush for 8 weeks then dry pasture for 2 weeks. Throughout this time, liveweights, plasma renin activity and wool growth (g/day) were measured. Greasy and clean fleece weights, and fleece characteristics were measured at 14 months of age, and greasy fleece weight was measured again at 22 months after grazing pasture. Offspring from ewes that consumed the high salt pellet had an 8 and 10% increased fleece weight at 14 and 22 months of age, respectively (P ≤ 0.01). Offspring of ewes that consumed saltbush also showed an 8% increase in greasy fleece weight at 22 months of age (P ≤ 0.05). Offspring from ewes that consumed saltbush had lower plasma renin activity and gained tissue weight when grazing saltbush (P ≤ 0.05), whereas the other three treatment groups all lost weight (P > 0.05). Grazing pregnant ewes on saltbush induces important adaptations in plasma renin activity of their offspring, which allows them to gain weight when grazing saltbush as adults and may also increase the density of their wool follicles. Grazing pregnant ewes on saltbush can profit farmers in three main ways: (i) ability to utilise salt-affected land; (ii) increase weight gain of sheep when grazing saltbush; and (iii) increase fleece weight.
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Arieli, A., E. Naim, R. W. Benjamin y D. Pasternak. "The effect of feeding saltbush and sodium chloride on energy metabolism in sheep". Animal Science 49, n.º 3 (diciembre de 1989): 451–57. http://dx.doi.org/10.1017/s0003356100032657.
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ABSTRACTThe effect of consumption of saltbush and sodium chloride on energy metabolism in sheep was investigated. Twenty-four Awassi wethers were fed at maintenance level and allotted to three treatments: saltbush (Atriplex barclayana), salt (NaCl) and control. Daily mineral intakes with these diets were 149, 158 and 57 g, respectively. The saltbush had been irrigated with an equal-part mixture of seawater and fresh water and contained 15 g nitrogen and 310 g ash per kg. Energy and nitrogen balance were conducted using indirect calorimetry. The disappearance of organic matter and nitrogen from saltbush in the rumen was studied by the polyester bag technique.Water intake of animals fed a high salt diet was 2·9 times higher and urine excretion was 3·7 times higher than in the control. Digested energy was proportionately 0·616 of dietary gross energy in the saltbush treatment, and 0·700 and 0·707 in the salt and control treatments respectively. Metabolizable energy (ME) was proportionately 0·795, 0·786 and 0·815 of digested energy, and heat production was 1·135, 1·043 and 0·867 of ME in the saltbush, salt and control treatments, respectively. The calculated values for digestible energy, ME, and net energy for maintenance on the saltbush diet were 5·02, 3·77 and 0·54 MJ/kg dry matter.It is suggested that the low energetic utilization of saltbush is related to its low digestibility and the associated increase in energy expenditure, which are apparently related to mineral metabolism in the rumen. To maintain sheep on saltbush diets efforts should be made to lower the mineral content of this shrub.
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Clift, DK, KL Dalton y JC Prior. "Bladder Saltbush (Atriplex vesicaria Heward Ex Benth) Regeneration on the Riverine Plain of South-Eastern Australia since 1983." Rangeland Journal 11, n.º 1 (1989): 31. http://dx.doi.org/10.1071/rj9890031.
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This study reviews the distribution of healthy bladder saltbush on the Riverine Plain of south-eastern Australia towards the end of 1986, as well as the characteristics of regeneration following the saltbush dieback of 1977-83. The area of bladder saltbush increased by 53 per cent, from 0.53 to 0.81 million ha, in the period 1983-86. A further 0.32 million ha, which previously supported saltbush, failed to regenerate. Variations in the pattern and progress of regeneration were closely related to variations in soil type and the effects of pre- and post-dieback grazing. Although the cause of dieback remains unknown, it would appear that much of the decline in the distribution of bladder saltbush could be attributed to post-dieback mismanagement of affected stands.
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Fancote, C. R., P. E. Vercoe, K. L. Pearce, I. H. Williams y H. C. Norman. "Backgrounding lambs on saltbush provides an effective source of Vitamin E that can prevent Vitamin E deficiency and reduce the incidence of subclinical nutritional myopathy during summer and autumn". Animal Production Science 53, n.º 3 (2013): 247. http://dx.doi.org/10.1071/an12039.
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Vitamin E deficiency is common in sheep during summer and autumn in Mediterranean environments because of the lack of green feed. Deficiency of Vitamin E can lead to the development of nutritional myopathy, a condition causing heart and skeletal muscle damage which, in severe cases, can lead to death of the animal. Saltbush (Atriplex spp.) contains high concentrations of Vitamin E, so providing sheep with access to saltbush during summer may improve their Vitamin E status and prevent Vitamin E deficiency. We wished to determine whether backgrounding lambs on saltbush over summer and autumn (i.e. graze saltbush-based pastures for several weeks before finishing them to condition suitable for slaughter) would prevent Vitamin E deficiency and nutritional myopathy and compared the effectiveness of this strategy in preventing Vitamin E deficiency to a commercially available synthetic Vitamin E supplement. Ten-month-old cross-bred lambs (n = 48) were backgrounded on dry, senesced (control) or saltbush-based pastures for 8 weeks during summer. After backgrounding they were fed a grain-based finishing ration containing low levels of Vitamin E for a further 5 weeks. We found that while grazing saltbush the plasma Vitamin E concentrations of lambs increased from 1.1 to 2.6 mg/L within 3 weeks, concentrations that were significantly higher than the concentrations in the lambs that did not have access to saltbush during backgrounding (P < 0.001). The improved Vitamin E concentrations corresponded with a reduction in the incidence of nutritional myopathy, with none of the lambs grazing saltbush showing any biochemical signs of myopathy, whereas 17% of lambs backgrounded on control pastures had elevated plasma concentrations of creatine kinase that were indicative of subclinical nutritional myopathy. During the subsequent finishing phase, lambs that had not had access to saltbush during backgrounding were all Vitamin E deficient and, of these, 8.5% were diagnosed with subclinical nutritional myopathy. By contrast, none of the lambs backgrounded on saltbush was Vitamin E deficient nor did they have any biochemical evidence of Vitamin E-responsive myopathy. The present study demonstrated that saltbush is a valuable source of Vitamin E for livestock that can reduce the incidence of subclinical nutritional myopathy in lambs during summer and prevent plasma Vitamin E concentrations becoming deficient for up to 5 weeks after saltbush is removed from the diet.
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Garza, Andres y Timothy E. Fulbright. "Comparative Chemical Composition of Armed Saltbush and Fourwing Saltbush". Journal of Range Management 41, n.º 5 (septiembre de 1988): 401. http://dx.doi.org/10.2307/3899576.
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Pearce, K. L., D. G. Masters, G. M. Smith, R. H. Jacob y D. W. Pethick. "Plasma and tissue α-tocopherol concentrations and meat colour stability in sheep grazing saltbush (Atriplex spp.)". Australian Journal of Agricultural Research 56, n.º 7 (2005): 663. http://dx.doi.org/10.1071/ar05001.
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Dry senesced pastures available during the summer and autumn period in Western Australia and other areas with a Mediterranean climate are low in vitamin E. The use of expensive and labour-intensive supplements to prevent nutritional myopathy induced by vitamin E deficiency in weaner sheep is common. Low vitamin E concentrations in the muscle preslaughter can also reduce the shelf life of meat. There is growing interest in incorporating saltbush into farming systems in Western Australia. The potential for saltbush to boost the vitamin E status of sheep and improve the shelf life of meat was investigated. Fifty (2 × 25) 18-month-old Merino hogget wethers (average liveweight 48 kg) were grazed on either a saltbush-dominant saline pasture or on a ‘control’ dry pasture, stubble plot for 14 weeks. At the start of the experiment, all animals were orally supplemented with 2500 IU of dl-α-tocopherol acetate in 6.25 mL solution. The α-tocopherol content in saltbush was 139 and 116 mg/kg dry matter for old man and river saltbush, respectively. Concentrations of α-tocopherol were measured in plasma at Weeks 0, 4, 8, and 12 and in muscle and liver samples taken at slaughter. Grazing on saltbush significantly elevated α-tocopherol concentrations in the liver and muscle compared with grazing on dry pasture, well above the threshold for vitamin E inadequacy (P < 0.001). Plasma α-tocopherol concentrations in sheep fed saltbush increased up to Week 8 and then decreased until the end of the experiment as availability of saltbush declined (P < 0.05). Plasma α-tocopherol in sheep fed dry pasture increased in the first 4 weeks due to the initial vitamin E treatment but declined thereafter, indicating that the pasture was low in vitamin E. The high muscle concentrations of α-tocopherol in sheep fed saltbush also improved colour stability and may have had an influence on drip and cooking loss. The meat from the saltbush-grazed sheep was moister but drip and cooking loss was the same as from the drier meat of the control sheep. In conclusion, this study demonstrates that saltbush is a potential vitamin E source for sheep.
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Stephens, Sydney Rae, Teri J. Orr y M. Denise Dearing. "Chiseling Away at the Dogma of Dietary Specialization in Dipodomys Microps". Diversity 11, n.º 6 (14 de junio de 2019): 92. http://dx.doi.org/10.3390/d11060092.
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Dipodomys microps, the chisel-toothed kangaroo rat, is heralded as one of few mammalian herbivores capable of dietary specialization. Throughout its range, the diet of D. microps is thought to consist primarily of Atriplex confertifolia (saltbush), a C4 plant, and sparing amounts of C3 plants. Using stable isotopes of carbon and nitrogen as natural diet tracers, we asked whether D. microps is an obligate specialist on saltbush. We analyzed hair samples of D. microps for isotopes from historic and recent museum specimens (N = 66). A subset of samples (N = 17) from 2017 that were associated with field notes on plant abundances were further evaluated to test how local saltbush abundance affects its inclusion in the diet of D. microps. Overall, we found that the chisel-toothed kangaroo rat facultatively specializes on saltbush and that the degree of specialization has varied over time and space. Moreover, saltbush abundance dictates its inclusion in the diet. Furthermore, roughly a quarter of the diet is comprised of insects, and over the past century, insects have become more prevalent and saltbush less prevalent in the diet. We suggest that environmental factors such as climate change and rangeland expansion have caused D. microps to include more C3 plants and insects.
Tesis sobre el tema "Saltbush"
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Chadwick, Megan. "Fetal programming of sheep for production on saltbush". University of Western Australia. School of Animal Biology, 2009. http://theses.library.uwa.edu.au/adt-WU2010.0033.
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[Truncated abstract] Saltbush is one of the few types of forage that will grow on salt affected land but, sheep struggle to maintain weight when grazing saltbush mainly because of its high salt content. Therefore, a strategy to improve salt tolerance of sheep would be beneficial to the profitable use of revegetated saline land. This could be done by manipulating the dietary salt load of pregnant or lactating ewes which could 'program', or permanently alter the physiology of their offspring to allow them to cope better with a high-salt diet as adults. When rat dams consume a high amount of salt during pregnancy, the salt balance mechanisms of their offspring are 'programmed' due to suppression of the offspring's renin-angiotensin system in early development. If this occurs in offspring from ewes grazing saltbush, beneficial adaptations may be programmed in these offspring which could allow them to better cope with the high-salt content of saltbush. I tested the general hypothesis that offspring born to ewes that consumed a high-salt or saltbush diet from mid-pregnancy to early lactation would have an increased capacity to cope with salt that would allow them gain weight when grazing saltbush in later life. To test this hypothesis, I pair-fed ewes either a high-salt diet (14% NaCl) or control diet (2% NaCl) in an animal house from day 60 of gestation until day 21 of lactation. During the same period, I also conducted a field experiment where ewes grazed on saltbush (supplemented with barley) or on pasture (supplemented with lupins). ... This led to the high-salt offspring retaining more salt than control animals. In contrast, the renin activity of saltbush was consistently lower than pasture offspring which allowed them to excrete salt more rapidly. In experiment three, the saltbush offspring gained tissue weight after grazing saltbush for 8 weeks, whereas the offspring in the other three treatments lost weight. High-salt and saltbush offspring also had higher greasy fleece weights at 22 months of age than their respective control groups. Feeding saltbush to ewes from mid-pregnancy to early lactation induces physiological adaptations in their offspring that allow them to cope better with salt and gain weight when grazing saltbush as adults, supporting my hypothesis. However, contrary to expectations, the high-salt offspring did not gain weight when grazing saltbush because their physiological adaptations, such as salt retention, did not allow them to cope better with a salt load. The reason that saltbush offspring showed different adaptations to highsalt offspring is likely to be because saltbush contains not only NaCl but also high amounts of other minerals such as potassium, and other plant compounds, which may influence the adaptive responses of the offspring. This research has direct implications for farmers because it shows they could utilize otherwise unproductive saltland by grazing pregnant ewes on saltbush to 'program' their offspring to gain weight when they graze saltbush later in life.
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Franklin-McEvoy, Jim. "Improving the performance of sheep grazing on saltbush /". Title page, table of contents and abstract only, 2002. http://web4.library.adelaide.edu.au/theses/09AB/09abf8312.pdf.
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Maywald, Dionne Lee. "Palatability variation between the sex phenotypes of bladder saltbush (Atriplex vesicaria)". Title page, contents and summary only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phm474.pdf.
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Bibliography: leaves 105-121. This study reports the first thorough investigation of palatability variation in Atriplex vesicaria Heward ex Benth. (bladder saltbush). Intensive small-plot dietary trials, supported by a paddock dietary experiment, cross-fence comparisons and cafeteria trials, showed that sheep preferentially grazed female saltbushes over male and bisexual ones. Sheep avoided male saltbushes due to a chemical deterrent, and used visual (male flower spike) and olfactory cues to detect male plants. The effect of this selective grazing was to reduce the size and reproductive output of female shrubs. Sheep also tended to return to shrubs they had grazed previously. In the semi-arid regions of South Australia, where bladder saltbush is grazed year-round, physical protection is recommended to maximise survival and reproductive output of heavily grazed shrubs.
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au, k. pearce@murdoch edu y Kelly L. Pearce. "Carcass and eating quality of sheep grazing saltbush based saline pasture systems". Murdoch University, 2006. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20070516.95025.
Texto completoResumen
Forage halophytes such as saltbush (Atriplex spp) are being widely used to revegetate Australian
saline land and can also provide a medium quality fodder source. There is widespread anecdotal
evidence that sheep grazing on saltbush are leaner, tastier and juicer. This thesis investigated the
potential to produce a high quality carcass with improved eating quality from grazing sheep on
saltbush on saline land.
The first experimental chapter in this thesis details an animal house experiment investigating the
carcass, eating and wool quality and physiological responses of sheep ingesting a 60:40 dried
saltbush (Atriplex nummularia):barley grain (S+B), ration verses a 33:25:42 lupin grain:barley
grain:oaten hay ration (Control, C) for 10 weeks prior to commercial slaughter (Chapter 4).
Subsequently, two field experiments were conducted to examine the effects of grazing saltbush
on saline land compared to dry senesced pasture on carcass and eating quality of lambs
(Goomalling 2003) and hoggets (Wickepin 2004) (both chapter 6) for 14 weeks. Both chapters
demonstrated that the ingestion of saltbush resulted in significantly less fat and in the 2 field
experiments the ingestion of saltbush resulted in more lean on the carcass compared to sheep
grazing a stubble/pasture (control) ration. These are positive findings for processors as costs of
fat denudation are high so the lower the fat content and for farmers because less fat is deposited
on the carcass per unit of liveweight gain. The decreased deposition of fat was attributed to the
higher protein:energy ratio available for production, secondary compounds in saltbush and lower
circulating insulin and higher growth hormone of the S+B fed sheep compared to the control fed
sheep. Further work is needed to determine if these beneficial improvements in carcass
composition can be achieved without compromising animal production. The long term grazing of
saltbush did not result in commercially desirable hot carcass weights unless the sheep were supplemented with a high energy source such as barley. The low growth rates are attributed to a
decreased availability of energy substrates, low feed intake and increased energy output of sheep
fed high salt diets. The low energy intake of the S+B fed sheep also resulted in an a significantly
lower percentage of unsaturated fat and unchanged levels of saturated fat in the fat depots
compared to the C treatment.
Consumer taste tests conducted on meat from experiments in both chapter 4 and 6 indicated no
difference between the treatments for any of the eating quality traits assessed. This can be
considered a positive result as sheep can be finished on saltbush without any detriment to eating
quality. High vitamin E levels in the meat may have also prevented the development of rancid
flavours and aroma. It can be speculated that saltbush does not impart beneficial flavour and
aroma volatiles as previously thought; instead the high vitamin E levels inhibit off-flavour and
aroma development compared to meat from sheep grazed on dry pasture.
The long term ingestion of saltbush also resulted in significantly lower urine specific gravity
(USG), muscle dry matter and higher urine weights suggesting that the saltbush fed sheep had a
better hydration status compared to control fed sheep. However, this finding did not correspond
with higher hot carcass weight or dressing percentages. The increases in muscle fluid content of
the saltbush fed sheep were attributed to changes in body composition. The saltbush fed sheep
had a higher lean and lower fat content which corresponded with a greater body fluid content as
found in the animal house study.
Under conditions where the body composition of sheep remains the same, the use of short term
strategic feeding of components of saltbush was investigated (mimicked in the form of salt and
betaine) to reduce dehydration and subsequent reductions in carcass weight and dressing percentages (Chapter 7). Salt and or betaine were fed for 1 week either prior to a 48 h period of
water deprivation or prior to 48 h commercial slaughter process where water was available in
lairage from 24-48 h. Under both scenarios the diets did not result in improved dressing
percentages, hot carcass weights, muscle dry matter or muscle weights. The ingestion of high salt
diet prior to slaughter, did increase fluid retention in the extracellular spaces prior to slaughter
however by 48 h both groups were at a similar physiological and therefore similar hydration
status. Therefore similar levels of fluid were present in the muscles and no difference in carcass
weight or dressing percentage could be expected. An important observation from the second
experiment was that the high salt group drunk more water than the low salt fed sheep but the low
salt group consumed fluid in lairage also. The low salt fed sheep may have been encouraged to
drink water after observing the frequent drinking patterns of the high salt group.
This thesis has also shown that saltbush contains high levels of vitamin E (á-tocopherol) (193
mg/kg dry matter). As a result the concentration of á-tocopherol in plasma, liver and muscle of
the saltbush fed sheep was elevated compared to those grazing dry pasture. The high muscle
concentrations of vitamin E in the saltbush-grazed sheep resulted in improved meat colour
stability. The high vitamin E levels did not influence the drip and cooking loss of the meat
despite a decrease in the muscle dry matter of the meat. The browning of meat and increased drip
loss results in large losses to the meat industry due to value deterioration at the supermarket.
There is also great potential for the high vitamin E content in saltbush to be used for the
prevention of nutritional myopathy instead of using expensive and labour intensive synthetic
supplements.
In conclusion, this thesis has provided an insight into the carcass and eating quality of sheep
grazed on saltbush based saline pasture systems. The most significant findings were that
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Pearce, Kelly Lynne. "Carcass and eating quality of sheep grazing saltbush based saline pasture systems /". Access via Murdoch University Digital Theses Project, 2006. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20070516.95025.
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Pearce, Kelly L. "Carcass and eating quality of sheep grazing saltbush based saline pasture systems". Thesis, Pearce, Kelly L. (2006) Carcass and eating quality of sheep grazing saltbush based saline pasture systems. PhD thesis, Murdoch University, 2006. https://researchrepository.murdoch.edu.au/id/eprint/252/.
Texto completoResumen
Forage halophytes such as saltbush (Atriplex spp) are being widely used to revegetate Australian saline land and can also provide a medium quality fodder source. There is widespread anecdotal evidence that sheep grazing on saltbush are leaner, tastier and juicer. This thesis investigated the potential to produce a high quality carcass with improved eating quality from grazing sheep on saltbush on saline land.
The first experimental chapter in this thesis details an animal house experiment investigating the carcass, eating and wool quality and physiological responses of sheep ingesting a 60:40 dried saltbush (Atriplex nummularia):barley grain (S+B), ration verses a 33:25:42 lupin grain:barley grain:oaten hay ration (Control, C) for 10 weeks prior to commercial slaughter (Chapter 4). Subsequently, two field experiments were conducted to examine the effects of grazing saltbush on saline land compared to dry senesced pasture on carcass and eating quality of lambs (Goomalling 2003) and hoggets (Wickepin 2004) (both chapter 6) for 14 weeks. Both chapters demonstrated that the ingestion of saltbush resulted in significantly less fat and in the 2 field experiments the ingestion of saltbush resulted in more lean on the carcass compared to sheep grazing a stubble/pasture (control) ration. These are positive findings for processors as costs of fat denudation are high so the lower the fat content and for farmers because less fat is deposited on the carcass per unit of liveweight gain. The decreased deposition of fat was attributed to the higher protein:energy ratio available for production, secondary compounds in saltbush and lower circulating insulin and higher growth hormone of the S+B fed sheep compared to the control fed sheep. Further work is needed to determine if these beneficial improvements in carcass composition can be achieved without compromising animal production. The long term grazing of saltbush did not result in commercially desirable hot carcass weights unless the sheep were supplemented with a high energy source such as barley. The low growth rates are attributed to a decreased availability of energy substrates, low feed intake and increased energy output of sheep fed high salt diets. The low energy intake of the S+B fed sheep also resulted in an a significantly lower percentage of unsaturated fat and unchanged levels of saturated fat in the fat depots compared to the C treatment.
Consumer taste tests conducted on meat from experiments in both chapter 4 and 6 indicated no difference between the treatments for any of the eating quality traits assessed. This can be considered a positive result as sheep can be finished on saltbush without any detriment to eating quality. High vitamin E levels in the meat may have also prevented the development of rancid flavours and aroma. It can be speculated that saltbush does not impart beneficial flavour and aroma volatiles as previously thought; instead the high vitamin E levels inhibit off-flavour and aroma development compared to meat from sheep grazed on dry pasture.
The long term ingestion of saltbush also resulted in significantly lower urine specific gravity (USG), muscle dry matter and higher urine weights suggesting that the saltbush fed sheep had a better hydration status compared to control fed sheep. However, this finding did not correspond with higher hot carcass weight or dressing percentages. The increases in muscle fluid content of the saltbush fed sheep were attributed to changes in body composition. The saltbush fed sheep had a higher lean and lower fat content which corresponded with a greater body fluid content as found in the animal house study.
Under conditions where the body composition of sheep remains the same, the use of short term strategic feeding of components of saltbush was investigated (mimicked in the form of salt and betaine) to reduce dehydration and subsequent reductions in carcass weight and dressing percentages (Chapter 7). Salt and or betaine were fed for 1 week either prior to a 48 h period of water deprivation or prior to 48 h commercial slaughter process where water was available in lairage from 24-48 h. Under both scenarios the diets did not result in improved dressing percentages, hot carcass weights, muscle dry matter or muscle weights. The ingestion of high salt diet prior to slaughter, did increase fluid retention in the extracellular spaces prior to slaughter however by 48 h both groups were at a similar physiological and therefore similar hydration status. Therefore similar levels of fluid were present in the muscles and no difference in carcass weight or dressing percentage could be expected. An important observation from the second experiment was that the high salt group drunk more water than the low salt fed sheep but the low salt group consumed fluid in lairage also. The low salt fed sheep may have been encouraged to drink water after observing the frequent drinking patterns of the high salt group.
This thesis has also shown that saltbush contains high levels of vitamin E (alpha-tocopherol) (193 mg/kg dry matter). As a result the concentration of alpha-tocopherol in plasma, liver and muscle of the saltbush fed sheep was elevated compared to those grazing dry pasture. The high muscle concentrations of vitamin E in the saltbush-grazed sheep resulted in improved meat colour stability. The high vitamin E levels did not influence the drip and cooking loss of the meat despite a decrease in the muscle dry matter of the meat. The browning of meat and increased drip loss results in large losses to the meat industry due to value deterioration at the supermarket. There is also great potential for the high vitamin E content in saltbush to be used for the prevention of nutritional myopathy instead of using expensive and labour intensive synthetic supplements.
In conclusion, this thesis has provided an insight into the carcass and eating quality of sheep grazed on saltbush based saline pasture systems. The most significant findings were that ingesting saltbush can reduce the carcass fat content, improve meat colour stability and not result in any detriment to eating quality. A potentially useful way to incorporate these results into an Australian farming system may be to use saltbush on a short term basis, not for the length of period grazed in this thesis. The short term use of saltbush should provide sufficient grazing time for an elevation of vitamin E levels in the muscle to improve meat colour stability, increase the amount of lean and decrease fat levels of a carcass all without changing eating quality and decreasing liveweight. Further work is needed to ensure that these benefits can be achieved without compromising animal production. The opportunity to utilise saltbush to produce leaner carcasses with better colour stability may encourage farmers to consider previously unproductive land planted to saltbush to be a highly useful enterprise.
7
Pearce, Kelly L. "Carcass and eating quality of sheep grazing saltbush based saline pasture systems". Pearce, Kelly L. (2006) Carcass and eating quality of sheep grazing saltbush based saline pasture systems. PhD thesis, Murdoch University, 2006. http://researchrepository.murdoch.edu.au/252/.
Texto completoResumen
Forage halophytes such as saltbush (Atriplex spp) are being widely used to revegetate Australian saline land and can also provide a medium quality fodder source. There is widespread anecdotal evidence that sheep grazing on saltbush are leaner, tastier and juicer. This thesis investigated the potential to produce a high quality carcass with improved eating quality from grazing sheep on saltbush on saline land.
The first experimental chapter in this thesis details an animal house experiment investigating the carcass, eating and wool quality and physiological responses of sheep ingesting a 60:40 dried saltbush (Atriplex nummularia):barley grain (S+B), ration verses a 33:25:42 lupin grain:barley grain:oaten hay ration (Control, C) for 10 weeks prior to commercial slaughter (Chapter 4). Subsequently, two field experiments were conducted to examine the effects of grazing saltbush on saline land compared to dry senesced pasture on carcass and eating quality of lambs (Goomalling 2003) and hoggets (Wickepin 2004) (both chapter 6) for 14 weeks. Both chapters demonstrated that the ingestion of saltbush resulted in significantly less fat and in the 2 field experiments the ingestion of saltbush resulted in more lean on the carcass compared to sheep grazing a stubble/pasture (control) ration. These are positive findings for processors as costs of fat denudation are high so the lower the fat content and for farmers because less fat is deposited on the carcass per unit of liveweight gain. The decreased deposition of fat was attributed to the higher protein:energy ratio available for production, secondary compounds in saltbush and lower circulating insulin and higher growth hormone of the S+B fed sheep compared to the control fed sheep. Further work is needed to determine if these beneficial improvements in carcass composition can be achieved without compromising animal production. The long term grazing of saltbush did not result in commercially desirable hot carcass weights unless the sheep were supplemented with a high energy source such as barley. The low growth rates are attributed to a decreased availability of energy substrates, low feed intake and increased energy output of sheep fed high salt diets. The low energy intake of the S+B fed sheep also resulted in an a significantly lower percentage of unsaturated fat and unchanged levels of saturated fat in the fat depots compared to the C treatment.
Consumer taste tests conducted on meat from experiments in both chapter 4 and 6 indicated no difference between the treatments for any of the eating quality traits assessed. This can be considered a positive result as sheep can be finished on saltbush without any detriment to eating quality. High vitamin E levels in the meat may have also prevented the development of rancid flavours and aroma. It can be speculated that saltbush does not impart beneficial flavour and aroma volatiles as previously thought; instead the high vitamin E levels inhibit off-flavour and aroma development compared to meat from sheep grazed on dry pasture.
The long term ingestion of saltbush also resulted in significantly lower urine specific gravity (USG), muscle dry matter and higher urine weights suggesting that the saltbush fed sheep had a better hydration status compared to control fed sheep. However, this finding did not correspond with higher hot carcass weight or dressing percentages. The increases in muscle fluid content of the saltbush fed sheep were attributed to changes in body composition. The saltbush fed sheep had a higher lean and lower fat content which corresponded with a greater body fluid content as found in the animal house study.
Under conditions where the body composition of sheep remains the same, the use of short term strategic feeding of components of saltbush was investigated (mimicked in the form of salt and betaine) to reduce dehydration and subsequent reductions in carcass weight and dressing percentages (Chapter 7). Salt and or betaine were fed for 1 week either prior to a 48 h period of water deprivation or prior to 48 h commercial slaughter process where water was available in lairage from 24-48 h. Under both scenarios the diets did not result in improved dressing percentages, hot carcass weights, muscle dry matter or muscle weights. The ingestion of high salt diet prior to slaughter, did increase fluid retention in the extracellular spaces prior to slaughter however by 48 h both groups were at a similar physiological and therefore similar hydration status. Therefore similar levels of fluid were present in the muscles and no difference in carcass weight or dressing percentage could be expected. An important observation from the second experiment was that the high salt group drunk more water than the low salt fed sheep but the low salt group consumed fluid in lairage also. The low salt fed sheep may have been encouraged to drink water after observing the frequent drinking patterns of the high salt group.
This thesis has also shown that saltbush contains high levels of vitamin E (alpha-tocopherol) (193 mg/kg dry matter). As a result the concentration of alpha-tocopherol in plasma, liver and muscle of the saltbush fed sheep was elevated compared to those grazing dry pasture. The high muscle concentrations of vitamin E in the saltbush-grazed sheep resulted in improved meat colour stability. The high vitamin E levels did not influence the drip and cooking loss of the meat despite a decrease in the muscle dry matter of the meat. The browning of meat and increased drip loss results in large losses to the meat industry due to value deterioration at the supermarket. There is also great potential for the high vitamin E content in saltbush to be used for the prevention of nutritional myopathy instead of using expensive and labour intensive synthetic supplements.
In conclusion, this thesis has provided an insight into the carcass and eating quality of sheep grazed on saltbush based saline pasture systems. The most significant findings were that ingesting saltbush can reduce the carcass fat content, improve meat colour stability and not result in any detriment to eating quality. A potentially useful way to incorporate these results into an Australian farming system may be to use saltbush on a short term basis, not for the length of period grazed in this thesis. The short term use of saltbush should provide sufficient grazing time for an elevation of vitamin E levels in the muscle to improve meat colour stability, increase the amount of lean and decrease fat levels of a carcass all without changing eating quality and decreasing liveweight. Further work is needed to ensure that these benefits can be achieved without compromising animal production. The opportunity to utilise saltbush to produce leaner carcasses with better colour stability may encourage farmers to consider previously unproductive land planted to saltbush to be a highly useful enterprise.
8
Jensen, Mari N. "Mine Tailings and Saltbush: Revegetating the Dusty Leftovers From Arizona's Storied Mining Past". College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2006. http://hdl.handle.net/10150/622146.
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Thacker, G. "Revegetation of Retired Farmland: Response of Fourwing Saltbush to Establishment Irrigations and Weeding". College of Agriculture, University of Arizona (Tucson, AZ), 1988. http://hdl.handle.net/10150/200850.
Texto completoResumen
Fourwing saltbush (Atriplex canescens) was seeded in 80 -inch wide water harvesting microcatchments on retired farmland west of Tucson. Eight months after planting the plots that had received one establishment irrigation and weeding had significantly more cover than the unirrigated and unweeded treatments. The percent cover of the uninigated /weeded and irrigated /unweeded treatments was not significantly different. Uninigated and unweeded plots had virtually no cover of saltbush. It appears that establishing saltbush in microcatchments of this size is not feasible without either an establishment irrigation or weed control.
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Thacker, Gary W. "Revegetation of Retired Farmland: Response of Fourwing Saltbush to Establishment Irrigation and Weeding". College of Agriculture, University of Arizona (Tucson, AZ), 1990. http://hdl.handle.net/10150/201265.
Texto completoResumen
This is an experiment on seeding fourwing saltbush (Atriplex canescens) in 80-inch wide waterharvesting microcatchments on retired farmland west of Tucson. At 32 months after planting plots that received the establishment irrigation had more cover than unirrigated plots. Keeping plots free of competing weeds also gave some advantage. However, the coefficient of variation was very high, and none of these differences was statistically significant.
Libros sobre el tema "Saltbush"
1
Sanderson, Stewart C. Fourwing saltbush (Atriplex canescens) seed transfer zones. Fort Collins, CO: U.S. Dept. of Agriculture, Forest Service, Rocky Mountain Research Station, 2004.
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2
Mirza, Sarwat N. Fourwing saltbush, a multipurpose shrub for the arid highlands of Balochistan. Quetta, Pakistan: Arid Zone Research Institute (AZRI), Pakistan Agricultural Research Council, 1995.
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3
Frappell, Leighton. Lords of the saltbush plains: Frontier squatters and the pastoral independence movement, 1856-1866. Melbourne: Australian Scholarly Pub., 2003.
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4
Wasser, Clinton H. Fourwing saltbush (Atriplex canescens): Section 7.5.3, US Army Corps of Engineers wildlife resources management manual. Vicksburg, Miss: U.S. Army Engineer Waterways Experiment Station, 1986.
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5
Knudsen, Peter Axel. Saltbrush & Sagebrush: The jubilee overlanders. Dallas, Texas (3700 Mockingbird Lane, 75205): E-Heart Press, 1986.
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6
Flint, Miriam. Three guided walks around Marske, Redcar & Saltburn. [Great Britain]: Cleveland & Teeside Local History Society, 1996.
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7
Meikle, Robert B. Saltburn: Altan an t-Salainn : glimpses of a village past. Inverness: St Michael Publishing, 2001.
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8
Bairstow, Martin. Railways around Whitby: Scarborough - Whitby - Saltburn, Malton- Goathland - Whitby, Esk Valley, Forge Valley and Gilling lines. Halifax: M. Bairstow, 1991.
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A. B. (Andrew Barton) Paterson. Saltbush Bill, J. P. Hard Press, 2006.
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10
'Santa Rita' fourwing saltbush. [Washington, D.C.?]: U.S. Dept. of Agriculture, Soil Conservation Service, 1989.
Buscar texto completoCapítulos de libros sobre el tema "Saltbush"
1
Sastry, K. Subramanya, Bikash Mandal, John Hammond, S. W. Scott y R. W. Briddon. "Atriplex micrantha (Twoscale saltbush)". En Encyclopedia of Plant Viruses and Viroids, 219–20. New Delhi: Springer India, 2019. http://dx.doi.org/10.1007/978-81-322-3912-3_99.
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2
Srivarathan, Sukirtha, Anh Dao Thi Phan, Olivia Wright, Daniel Cozzolino, Yasmina Sultanbawa y Michael E. Netzel. "Saltbush ( Atriplex sp.)". En Handbook of Phytonutrients in Indigenous Fruits and Vegetables, 1–10. GB: CABI, 2022. http://dx.doi.org/10.1079/9781789248067.0001.
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Atiq-ur-Rehman. "Role of saltbush (Atriplex Spp.) in animal production systems of Mediterranean climate". En Tasks for vegetation science, 385–401. Dordrecht: Springer Netherlands, 2002. http://dx.doi.org/10.1007/978-94-017-0067-2_40.
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Ahmed, Mohommed y Mohommed Khair. "Prospects for saltbush (Atriplex spp.) as animal feed in irrigated and marginal lands in Sudan". En Halophytes as a resource for livestock and for rehabilitation of degraded lands, 235–37. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-0818-8_19.
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Nedjimi, Bouzid. "Heavy Metal Tolerance in Two Algerian Saltbushes: A Review on Plant Responses to Cadmium and Role of Calcium in Its Mitigation". En Plant Nutrients and Abiotic Stress Tolerance, 205–20. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-9044-8_9.
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"Improving the Feeding Value of Old Man Saltbush for Saline Production Systems in Australia". En Halophytic and Salt-Tolerant Feedstuffs, 105–12. CRC Press, 2015. http://dx.doi.org/10.1201/b19862-13.
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Norman, H., E. Hulm y M. Wilmot. "Improving the Feeding Value of Old Man Saltbush for Saline Production Systems in Australia". En Halophytic and Salt-Tolerant Feedstuffs, 79–86. CRC Press, 2015. http://dx.doi.org/10.1201/b19862-7.
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"Ecophysiological Aspects of the Vegetative Propagation of Saltbush (Atriplex spp.) and Mulberry (Morus spp.)". En Handbook of Plant and Crop Physiology, 149–64. CRC Press, 2001. http://dx.doi.org/10.1201/9780203908426-9.
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Sen, David y Pramila Rajput. "Ecophysiological Aspects of the Vegetative Propagation of Saltbush (Atriplex spp.) and Mulberry (Morus spp.)". En Handbook of Plant and Crop Physiology. CRC Press, 2001. http://dx.doi.org/10.1201/9780203908426.ch6.
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Hart, Richard H. y Justin D. Derner. "Cattle Grazing on the Shortgrass Steppe". En Ecology of the Shortgrass Steppe. Oxford University Press, 2008. http://dx.doi.org/10.1093/oso/9780195135824.003.0021.
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Cattle are the primary grazers on the shortgrass steppe. For example, during the late 1990s, 21 shortgrass counties in Colorado reported about 2.36 million cattle compared with 283,000 sheep (National Agricultural Statistics Service, USDA, 1997a), 60,000 pronghorn antelope, and a few thousand bison (Hart, 1994). Assuming one bison or five to six sheep or pronghorn consume as much forage as one bovine (Heady and Child, 1994), cattle provide about 97% of the large-herbivore grazing pressure in this region. The ratio of cattle to other grazers is even greater in the remainder of the shortgrass steppe. In 1997, the three panhandle counties of Oklahoma reported 387,000 cattle and only 1300 sheep, whereas the 38 panhandle counties of Texas reported 4.24 million cattle and 14,000 sheep (National Agricultural Statistics Service, USDA, 1997b,c). How ever, only a bout half the cattle in the panhandle counties of Texas and Oklahoma graze on rangeland the remainer are in feedlots. Rangeland research on the shortgrass steppe (Table 17.1 describes the parameters of the major research stations in the shortgrass steppe) has included a long history of both basic ecology and grazing management. The responses of rangeland plant communities to herbivory are addressed by Milchunas et al. (chapter 16, this volume) and to disturbance are discussed by Peters et al. (chapter 6, this volume). Here we focus on research pertaining to three management practices important to cattle ranching on shortgrass steppe: stocking rates, grazing systems, and extending the grazing season via complementary pastures and use of pastures dominated by Atriplex canescens [Pursh] Nutt (fourwing saltbush). Stocking rate, de. ned as the number of animals per unit area for a speci. ed time period, is the primary and most easily controlled variable in the management of cattle grazing. Cattle weight gain responses to stocking rate or grazing pressure (animal days per unit of forage produced) have been quanti. ed in several grazing studies on the shortgrass steppe (Bement, 1969, 1974; Hart and Ashby, 1998; Klipple and Costello, 1960). Average daily gains per animal are better estimated as a function of grazing pressure, rather than stocking rate, as forage production is highly variable in this semiarid environment (Lauenroth and Sala, 1992; Milchunas et al., 1994).
Informes sobre el tema "Saltbush"
1
Sanderson, Stewart C. y Durant E. McArthur. Fourwing saltbush (Atriplex canescens) seed transfer zones. Ft. Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, 2004. http://dx.doi.org/10.2737/rmrs-gtr-125.
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