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Ponnampalam E.N.,Australian Sheep Industry Cooperative Research Center | Ponnampalam E.N.,Australian Department of Primary Industries and Fisheries | Warner R.D.,Australian Department of Primary Industries and Fisheries | Kitessa S.,CSIRO | And 4 more authors.
Animal Production Science | Year: 2010

Thirty 7-month-old crossbred lambs (Poll Dorset Border Leicester Merino) finished over 5 weeks on either low quality pasture or grain-with-hay on a farm in southern Victoria were assessed for carcass parameters, muscle fat composition and retail colour stability. Lambs on the grain diet had a mix of barley grain (80%) and lentils (20%) at 800 g/head.day (air-dry basis ∼ad libitum) with cape weed (Arctotheca calendula) hay available at all times. Lambs under grazing had predominantly rye grass (Lolium perenne) and barley grass (Hordeum leporinum) available ad libitum. Carcass weight tended to be higher (P ≤ 0.14) in grain-fed lambs than in grass-fed lambs, but fatness indicated by GR (total muscle + fat tissue thickness at 11 cm from midline) did not differ between feeding systems. Fatty acid composition was determined in the loin from the forequarter (M. longissimus thoracis) and lumbar (M. longissimus lumborum) regions and from the leg region (M. semimembranosus). This showed that grain-finished lamb had higher muscle fat (P 0.001) and omega-6 fatty acid (P 0.001) content. Alpha-linolenic acid, eicosapentaenoic acid (EPA) or total omega-3 fat did not differ (P 0.05) between feeding groups. Saturated fatty acids were greater (P 0.01) in both loin sampling sites than the leg. The levels of EPA, docosahexaenoic acid and docosapentaenoic acid were lower (P 0.01) in the forequarter (9%) or lumbar (11%) sites than the leg sampling site. The distribution pattern of fatty acids across the three sampling sites did not differ between feed types. Retail colour stability determined over 4 days of display (only performed in muscle from the lumbar site), evaluated by the redness (HunterLab a*-value) and metmyoglobin formation (reflectance ratio at 630:580-nm wavelengths) was superior for grass-fed lamb compared with short-term grain-finished lamb. The results demonstrate that the health claimable omega-3 fat mainly EPA or total omega-3 fat content in lamb was not altered by short-term grain finishing compared with lamb finished under pasture grazing conditions. © 2010 CSIRO. Source

Taylor D.B.,University of New England of Australia | Taylor D.B.,Australian Sheep Industry Cooperative Research Center | Price I.R.,University of New England of Australia | Brown W.Y.,University of New England of Australia | And 2 more authors.
Small Ruminant Research | Year: 2011

This study examined if Merino sheep trained to respond to a combined visual and auditory stimulus could influence the movement of naïve Merino sheep flocks when the stimulus was activated. Trained Merino ewes were mixed with naive ewes and wethers in three groups of different sizes. Group ratios were (trained:naïve) Small Mob (SM) 1:5 ratio (n=18), Medium Mob (MM) 1:10 (n=33) and Large Mob (LM) 1:15 (n=48). These groups were tested in 2 phases of increasing complexity. The first phase examined the responses of the different sized flocks (SM, MM and LM) to leader-initiated movement in 3 visually open paddocks (OP) during morning and afternoon grazing. The second phase examined the response of two flocks (SM and LM) at similar times but in 3 visually complex paddocks (CP). Animal groups were tested on 1 day per week in each paddock at pseudo random times. One hundred percent of the SM, 73.5% of the MM and 70% of the LM approached within 6 m of the stimulus in the OP tests. In the CP 100% of the SM and 56.5% of the LM approached the stimulus. The LM's proximity to the stimulus in some of the CP tests was more than 6. m, however, it was not significant compared to the other CP or OP tests. Sixty seven percent of the SM animals and 33% of the LM of naïve sheep were observed to initiate movement toward the stimulus after the 6 tests in phase one. At the end of the first phase of testing the proportion of naïve sheep observed to be eating the previously unknown grain (lupins) was SM 73%, MM 60% and LM 36%, suggesting that naïve sheep will learn to eat a novel grain by following trained animals. Sub-grouping of the flock in this study was not a hindrance to flock movement. This study demonstrated that sheep trained to respond to a stimulus do provide leadership when mixed with naive sheep flocks causing a flock to rapidly change position to congregate around an activated stimulus. These findings suggest that trained animals could be used to manipulate animal movement for farm management purposes. © 2011 Elsevier B.V. Source

Ponnampalam E.N.,Australian Sheep Industry Cooperative Research Center | Ponnampalam E.N.,Australian Department of Primary Industries and Fisheries | Butler K.L.,Australian Department of Primary Industries and Fisheries | Pearce K.M.,Australian Sheep Industry Cooperative Research Center | And 9 more authors.
Meat Science | Year: 2014

The sources of variation of health claimable omega-3 polyunsaturated fatty acids (eicosapentaenoic acid, EPA. +. docosahexaenoic acid, DHA) in 2000 Australian lambs were investigated using 98 sires (Merino, maternal or terminal breeds) that were mated to about 5000 Merino or crossbred (Border Leicester. ×. Merino) ewes. Pasture was supplemented with feedlot pellets, grains or hay as necessary, when the availability of quality green pasture was limited. Lambs were grown at 8 sites across Australia and when slaughtered the longissimus lumborum muscle was collected. Site and kills within sites were the major sources of variation for health claimable fatty acids. These environmental effects are likely to be driven by dietary background. The sire variance differed from about one twentieth to a half of the residual lamb within dam variation, depending on site and kill. This is the first comprehensive study to investigate on-farm sources of variation of long chain omega-3 polyunsaturated fatty acid content of lamb meat. © 2012 The Authors. Source

Goopy J.P.,Industry and Investment NSW | Goopy J.P.,Australian Sheep Industry Cooperative Research Center | Woodgate R.,Industry and Investment NSW | Donaldson A.,Industry and Investment NSW | And 5 more authors.
Animal Feed Science and Technology | Year: 2011

There is increasing demand for technologies to measure CH4 production (DMP) of ruminant livestock in inventory and mitigation research. Studies of genetic variation among animals in DMP require these emissions to be measured on thousands of animals which cannot be managed using traditional chamber studies. However, short-term emission measures have been reported to correlate well with DMP. Our study was conducted to determine the usefulness of 1 and 2h emission measures using chambers in predicting DMP. In our first experiment, Merino sheep (n=13) were measured for DMP over 22h using open circuit chambers. On two subsequent days, after overnight fasts, sheep were offered feed for 1h before return to the chambers for 2h and their CH4 production determined. DMP estimated from 22h measurements correlated moderately well with 2h emission measures (r2 of 0.42-0.48) and 1h measures (r2 of 0.39-0.43). In our second experiment, portable static chambers were designed for 1 and 2h CH4 emission measurements. The portable static chambers retained 98-99% of an injected tracer gas after 2h showing that gas leakage from the chamber was very low. With a sheep inside a portable static chamber, CO2 concentration reached 2.2×103ppmv after 2h, but sheep showed no discomfort and the partial pressure of O2 in their blood remained above 97% (i.e., safe for animal health). Our third experiment was to validate use of short-term emission measures from portable static chambers as predictors of DMP. Crossbred Dorset and Border Leicester and Merino ewes (n=40, LW 54±10.9kg) were measured for three 22h sessions in open circuit chambers, after which they were measured for 1h in portable static chambers. Open circuit chamber measurements had high repeatability (i.e., 0.88) and, excluding one sheep with inconsistent eating patterns, the correlation (r) between 1h portable static chamber measurements and average emissions in the open circuit chambers was 0.71. We conclude that 1 and 2h measures of CH4 output in portable static chambers are useful for determining genetic differences in CH4 production in groups of ruminants. This article is part of the special issue entitled: Greenhouse Gases in Animal Agriculture - Finding a Balance between Food and Emissions, Guest Edited by T.A. McAllister, Section Guest Editors; K.A. Beauchemin, X. Hao, S. McGinn and Editor for Animal Feed Science and Technology, P.H. Robinson. © 2011 Elsevier B.V. Source

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