Sample records for hoggets
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Soil and agronomic factors associated with cadmium accumulations in kidneys of grazing sheep.
Morcombe, P W; Petterson, D S; Ross, P J; Edwards, J R
1994-12-01
Mean concentration of cadmium (Cd) in kidneys of hogget sheep from 67 flocks grazing in the Agricultural Region of Western Australia was tested for association with soil, pastoral, climatic and nutritional factors. Hoggets grazing pastures on acidic soils and soils with a sandy-textured surface had higher Cd concentrations in kidneys than hoggets grazing pastures on more alkaline soils or soils with a clay-textured surface. Application of more than 100 kg of phosphatic fertiliser during the past 3 years to loamy soils was also associated with greater Cd concentration in kidneys of the grazing animals.
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Greeff, J C; Safari, E; Fogarty, N M; Hopkins, D L; Brien, F D; Atkins, K D; Mortimer, S I; van der Werf, J H J
2008-06-01
Genetic parameters for carcass and meat quality traits of about 18-month-old Merino rams (n = 5870), the progeny of 543 sires from three research resource flocks, were estimated. The estimates of heritability for hot carcass weight (HCW) and the various fat and muscle dimension measurements were moderate and ranged from 0.20 to 0.37. The brightness of meat (colour L*, 0.18 +/- 0.03 standard error) and meat pH (0.22 +/- 0.03) also had moderate estimates of heritability, although meat relative redness (colour a*, 0.10 +/- 0.03) and relative yellowness (colour b*, 0.10 +/- 0.03) were lower. Heritability estimates for live weights were moderate and ranged from 0.29 to 0.41 with significant permanent maternal environmental effects (0.13 to 0.10). The heritability estimates for the hogget wool traits were moderate to high and ranged from 0.27 to 0.60. The ultrasound measurements of fat depth (FATUS) and eye muscle depth (EMDUS) on live animals were highly genetically correlated with the corresponding carcass measurements (0.69 +/- 0.09 FATC and 0.77 +/- 0.07 EMD). Carcass tissue depth (FATGR) had moderate to low genetic correlations with carcass muscle measurements [0.18 +/- 0.10 EMD and 0.05 +/- 0.10 eye muscle area (EMA)], while those with FATC were negative. The genetic correlation between EMD and eye muscle width (EMW) was 0.41 +/- 0.08, while EMA was highly correlated with EMD (0.89 +/- 0.0) and EMW (0.78 +/- 0.04). The genetic correlations for muscle colour with muscle measurements were moderately negative, while those with fat measurements were close to zero. Meat pH was positively correlated with muscle measurements (0.14 to 0.17) and negatively correlated with fat measurements (-0.06 to -0.18). EMDUS also showed a similar pattern of correlations to EMD with meat quality indicator traits, although FATUS had positive correlations with these traits which were generally smaller than their standard error. The genetic correlations among the meat colour traits were
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More feed efficient sheep produce less methane and carbon dioxide when eating high-quality pellets.
Paganoni, B; Rose, G; Macleay, C; Jones, C; Brown, D J; Kearney, G; Ferguson, M; Thompson, A N
2017-09-01
The Australian sheep industry aims to increase the efficiency of sheep production by decreasing the amount of feed eaten by sheep. Also, feed intake is related to methane production, and more efficient (low residual feed intake) animals eat less than expected. So we tested the hypothesis that more efficient sheep produce less methane by investigating the genetic correlations between feed intake, residual feed intake, methane, carbon dioxide, and oxygen. Feed intake, methane, oxygen, and carbon dioxide were measured on Merino ewes at postweaning (1,866 at 223 d old), hogget (1,010 sheep at 607 d old), and adult ages (444 sheep at 1,080 d old). Sheep were fed a high-energy grower pellet ad libitum for 35 d. Individual feed intake was measured using automated feeders. Methane was measured using portable accumulation chambers up to 3 times during this feed intake period. Heritabilities and phenotypic and genotypic correlations between traits were estimated using ASReml. Oxygen (range 0.10 to 0.20) and carbon dioxide (range 0.08 to 0.28) were generally more heritable than methane (range 0.11 to 0.14). Selecting to decrease feed intake or residual feed intake will decrease methane (genetic correlation [] range 0.76 to 0.90) and carbon dioxide ( range 0.65 to 0.96). Selecting to decrease intake ( range 0.64 to 0.78) and methane ( range 0.81 to 0.86) in sheep at postweaning age would also decrease intake and methane in hoggets and adults. Furthermore, selecting for lower residual feed intake ( = 0.75) and carbon dioxide ( = 0.90) in hoggets would also decrease these traits in adults. Similarly, selecting for higher oxygen ( = 0.69) in hoggets would also increase this trait in adults. Given these results, the hypothesis that making sheep more feed efficient will decrease their methane production can be accepted. In addition, carbon dioxide is a good indicator trait for feed intake because it has the highest heritability of the gas traits measured; is cheaper, faster, and
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Genetic correlations among and between wool, growth and reproduction traits in Merino sheep.
Safari, E; Fogarty, N M; Gilmour, A R; Atkins, K D; Mortimer, S I; Swan, A A; Brien, F D; Greeff, J C; van der Werf, J H J
2007-04-01
Data from seven research resource flocks across Australia were combined to provide accurate estimates of genetic correlations among production traits in Merino sheep. The flocks represented contemporary Australian Merino fine, medium and broad wool strains over the past 30 years. Over 110,000 records were available for analysis for each of the major wool traits, and 50,000 records for reproduction and growth traits with over 2700 sires and 25,000 dams. Individual models developed from the single trait analyses were extended to the various combinations of two-trait models to obtain genetic correlations among six wool traits [clean fleece weight (CFW), greasy fleece weight, fibre diameter (FD), yield, coefficient of variation of fibre diameter and standard deviation of fibre diameter], four growth traits [birth weight, weaning weight, yearling weight (YWT), and hogget weight] and four reproduction traits [fertility, litter size, lambs born per ewe joined, lambs weaned per ewe joined (LW/EJ)]. This study has provided for the first time a comprehensive matrix of genetic correlations among these 14 wool, growth and reproduction traits. The large size of the data set has also provided estimates with very low standard errors. A moderate positive genetic correlation was observed between CFW and FD (0.29 +/- 0.02). YWT was positively correlated with CFW (0.23 +/- 0.04), FD (0.17 +/- 0.04) and LWEJ (0.58 +/- 0.06), while LW/EJ was negatively correlated with CFW (-0.26 +/- 0.05) and positively correlated with FD (0.06 +/- 0.04) and LS (0.68 +/- 0.04). These genetic correlations, together with the estimates of heritability and other parameters provide the basis for more accurate prediction of outcomes in complex sheep-breeding programmes designed to improve several traits.
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Implications of intensification of pastoral animal production on animal welfare.
Stafford, Kj; Gregory, Ng
2008-12-01
The intensification of pastoral animal production results from several major developments including increased forage production and utilisation, diet supplementation, breeding animals to increase milk, meat or wool production, and changes in management. The impact of increased intensification on welfare will differ across species and systems. More intensive-grazing systems and the feeding of novel forages will underpin all moves to intensification. More intensive grazing generally reduces opportunities for shade and shelter. Improved nutrition will generally benefit welfare but competition for available feed may cause increased social pressure. Increased flock and herd size will be associated with a reduction in the human:animal ratio and less time to observe individual animals. Remote monitoring of activity and health might counter this impact. Intensification of dairy production will result in larger herds, more year-round milking, robotic milking, use of housing and yards year round, and total mixed-ration feeding. Larger herds mean longer distances to walk to and from the dairy shed, and more lameness and less time to spend on self-maintenance activities such as grooming. Holding and feeding dairy cows on yards will cause an increase in lameness and mastitis and perhaps an increase in agonistic behaviour but will reduce time spent walking. Intensification of sheep production will involve increased flock size, increased fecundity, breeding from hoggets, and breeding ewes all year round. Housing during lambing might be considered appropriate, as would feeding to lift milk yields. Increased fecundity with an increase in triplets will increase lamb mortality rates, but housing ewes, when managed well, will result in reduced lamb mortality. Intensification of lamb finishing will be by improved nutrition. Intensification of beef production will include more breeding of heifers at 15 months, and more problems with dystocia. Intensification of pastoral production will
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Effectiveness of copper oxide wire particles for Haemonchus contortus control in sheep.
Knox, M R
2002-04-01
To assess the efficacy of copper oxide wire particles (COWP) for the control of H contortus infections in grazing sheep. In experiment 1, 40 worm-free Merino hoggets (11 to 12 months of age) were divided into four equal groups and allocated to separate 0.8 ha pasture plots. Two groups then received 2.5 g COWP whereas the other two groups were untreated. From 1 week after COWP treatment all lambs received a weekly infection of 2000 H contortus larvae. At week 8, six sheep from the untreated group were then allocated to two groups and treated with either 2.5 or 5.0 g of COWP to establish therapeutic efficacy of treatment. Experiment 2 followed a similar protocol but was conducted with 40 worm-free Merino lambs (3 to 4 months of age) and no assessment of therapeutic efficacy was made. In experiment 1 no significant difference in faecal worm egg counts was observed between treatments and faecal worm egg counts remained less than 3000 epg in all animals. Total worm counts were reduced by 37% by COWP treatment (P = 0.055). Both 2.5 g and 5.0 g doses of COWP at 8 weeks of infection reduced faecal worm egg counts by > 85% with the higher dose giving an earlier response to treatment. In experiment 2, faecal worm egg counts at 4 and 6 weeks were reduced by more than 90% in the COWP treated lambs and worm numbers were 54% lower after 6 weeks when all remaining untreated lambs had to be treated for haemonchosis. Mean faecal worm egg counts in the COWP lambs remained below 3500 epg and clinical disease did not develop in the majority of lambs before the end of the experiment at 10 weeks. Treatment with COWPs appears to have the potential to reduce establishment and worm fecundity of Haemonchus spp for an extended period and may offer livestock producers a supplementary means of reducing larval contamination of pasture particularly in areas where anthelmintic resistance is a problem and copper supplementation is likely to be beneficial.
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di Virgilio, Agustina; Morales, Juan Manuel
2016-01-01
Background. A large proportion of natural grasslands around the world is exposed to overgrazing resulting in land degradation and biodiversity loss. Although there is an increasing effort in the promotion of sustainable livestock management, rangeland degradation still occurs because animals' foraging behaviour is highly selective at different spatial scales. The assessment of the ecological mechanisms modulating the spatial distribution of grazing and how to control it has critical implications for long term conservation of resources and the sustainability of livestock production. Considering the relevance of social interactions on animals' space use patterns, our aim was to explore the potential effects of including animals' social context into management strategies using domestic sheep grazing in rangelands as case study. Methods. We used GPS data from 19 Merino sheep (approximately 10% of the flock) grazing on three different paddocks (with sizes from 80 to 1000 Ha) during a year, to estimate resource selection functions of sheep grazing in flocks of different levels of heterogeneity. We assessed the effects of sheep class (i.e., ewes, wethers, and hoggets), age, body condition and time since release on habitat selection patterns. Results. We found that social rank was reflected on sheep habitat use, where dominant individuals (i.e., reproductive females) used more intensively the most preferred areas and low-ranked (i.e., yearlings) used less preferred areas. Our results showed that when sheep grazed on more heterogeneous flocks, grazing patterns were more evenly distributed at all the paddocks considered in this study. On the other hand, when high-ranked individuals were removed from the flock, low-ranked sheep shifted their selection patterns by increasing the use of the most preferred areas and strongly avoided to use less preferred sites (i.e., a highly selective grazing behaviour). Discussion. Although homogenization and segregation of flocks by classes
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Towards evenly distributed grazing patterns: including social context in sheep management strategies
Morales, Juan Manuel
2016-01-01
Background. A large proportion of natural grasslands around the world is exposed to overgrazing resulting in land degradation and biodiversity loss. Although there is an increasing effort in the promotion of sustainable livestock management, rangeland degradation still occurs because animals’ foraging behaviour is highly selective at different spatial scales. The assessment of the ecological mechanisms modulating the spatial distribution of grazing and how to control it has critical implications for long term conservation of resources and the sustainability of livestock production. Considering the relevance of social interactions on animals’ space use patterns, our aim was to explore the potential effects of including animals’ social context into management strategies using domestic sheep grazing in rangelands as case study. Methods. We used GPS data from 19 Merino sheep (approximately 10% of the flock) grazing on three different paddocks (with sizes from 80 to 1000 Ha) during a year, to estimate resource selection functions of sheep grazing in flocks of different levels of heterogeneity. We assessed the effects of sheep class (i.e., ewes, wethers, and hoggets), age, body condition and time since release on habitat selection patterns. Results. We found that social rank was reflected on sheep habitat use, where dominant individuals (i.e., reproductive females) used more intensively the most preferred areas and low-ranked (i.e., yearlings) used less preferred areas. Our results showed that when sheep grazed on more heterogeneous flocks, grazing patterns were more evenly distributed at all the paddocks considered in this study. On the other hand, when high-ranked individuals were removed from the flock, low-ranked sheep shifted their selection patterns by increasing the use of the most preferred areas and strongly avoided to use less preferred sites (i.e., a highly selective grazing behaviour). Discussion. Although homogenization and segregation of flocks by
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The effect of ingesting a saltbush and barley ration on the carcass and eating quality of sheepmeat.
Pearce, K L; Pethick, D W; Masters, D G
2008-03-01
Forage halophytes such as saltbush (Atriplex spp.) are widely used to revegetate Australian saline land and can provide a medium-quality fodder source. An animal house experiment was conducted to investigate differences in the carcass and eating quality of sheep ingesting saltbush from saline land in combination with a barley supplement. Twenty-six merino hoggets (two groups of 13) were fed either a 60 : 40 dried saltbush (Atriplex nummularia): barley (S + B) ration or a 33 : 25 : 42 lupins : barley : oaten hay ration (C) for 10 weeks prior to commercial slaughter. After 10 weeks, all sheep were commercially slaughtered and a single loin (from 12th rib to chump) collected from each animal for taste-panel analysis. Carcass weight, total tissue depth over the 12th rib 110 mm from the midline (GR fat depth), ultimate pH and colour were determined and X-ray bone densitometry used to estimate the fat content of the carcass. Blood samples were taken to assess the hormonal response to ingesting these diets and fatty acid profiles of the subcutaneous and intramuscular fat were determined. Both groups grew at the same rate (62 g/day) and had similar hot carcass weights (P > 0.01) (17.2 ± 0.3 kg for S + B and 17.9 ± 0.3 kg for C). However, these live weights may not be high enough to be commercially viable such that saltbush and barley may only be suitable as a maintenance feed. The S + B-fed sheep had a significantly (P = 0.055) lower fat and higher lean content (P < 0.05) than the C group. This is a positive finding as fat denudation is a significant cost to processors and farmers can produce sheep that are depositing less fat or more lean per unit of live-weight gain. The decreased fat and increased lean content were attributed to the higher protein : energy ratio available for production and lower circulating insulin and higher growth hormone of the S + B-fed sheep. The lower body-fat content and lower metabolisable energy and digestible organic matter intake did
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Jonker, A; Lowe, K; Kittelmann, S; Janssen, P H; Ledgard, S; Pacheco, D
2016-08-01
Feeding grain and corn silage have been proposed as practices to reduce enteric methane (CH) emissions per unit of intake from ruminants, but the inclusion level required in the diet is normally not specified. The objectives of the current study were to determine the CH emission factor (g/kg DMI) of sheep fed alfalfa silage substituted with increasing levels of corn silage or corn grain at a fixed DMI level (2% of BW) and determine its relationship with rumen fermentation characteristics and microbial community composition and with in vitro fermentation characteristics of the same diets incubated using a standard laboratory method. Romney ewe hoggets (approximately 14 mo old; = 64) were randomly allocated to 8 dietary treatments, which included chaffed alfalfa silage alone or substituted with either 25, 50, 75 or 100% corn silage or 25, 50 or 65% rolled corn grain on a DM basis. After acclimatization to the diet, DMI and CH emissions were measured from individual sheep for 2 consecutive days in open-circuit respiration chambers and a rumen sample was collected at 3 h after feeding. The same diets were also incubated in an automated in vitro gas production system for 48 h using rumen liquid of fistulated nonlactating dairy cows grazing pasture. Increasing the substitution of alfalfa silage with corn silage or corn grain in the diet of sheep resulted in a quadratic response ( < 0.01) in CH emissions per unit of DMI (CH/DMI) with either supplement. For both supplements, CH/DMI increased in mixtures of up to 50% supplement inclusion and then decreased with greater supplement inclusion, especially with corn grain inclusion, but the level did not fall below that for 100% alfalfa silage. The ratio of acetate + butyrate to propionate + valerate and the propionate proportion alone in rumen liquid were the strongest single predictors for CH/DMI in the overall data set and explained 37.1 and 32.5%, respectively, of the variation in CH/DMI. Methanogens of (21.1% of total