Australian Journal of Experimental Agriculture最新文献

{"title":"Dissection of beef quality phenotypes using a myogenin network-anchored systems biology approach","authors":"A. Reverter, E. Chan, S. Lehnert, W. Barris, S. McWilliam, B. Dalrymple, W. Barendse","doi":"10.1071/EA08052","DOIUrl":"https://doi.org/10.1071/EA08052","url":null,"abstract":"In order to uncover genes with transcriptional activity linked to various beef quality phenotypes of interest, we designed a systems biology approach. We focussed on traits representing the three major categories of growth and development, fat depots and meat quality phenotypes. We proceeded by linking bovine gene expression data derived from 147 microarray hybridisation experiments and high density marker data from 9260 single nucleotide polymorphisms (SNP) on 189 steers. The individuals in the genotyping study were unrelated to the samples used for expression profiling. The linkage was performed by anchoring these data to a gene network for myogenin (MYOG), a muscle-specific transcription factor essential for the development of skeletal muscle. This approach was able to identify and estimate the strength of the relationship between the statistical association of a SNP to a phenotype of interest with the transcriptional activity of genes in the network. The genes from the MYOG-centred network that were significantly associated with the largest number of meat quality traits were PDLIM3, CALM1 and CRYAB. Among our findings, a novel association between desmin and meat colour points to an alternative biochemical basis for meat colour differences involving costameric structures and their previously reported relationship with tenderness. These newly generated hypotheses can help formulate sound research to further illuminate the genetic architecture of beef quality phenotypes.","PeriodicalId":8636,"journal":{"name":"Australian Journal of Experimental Agriculture","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1071/EA08052","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"58803495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cashmere production and fleece attributes associated with farm of origin, age and sex of goat in Australia","authors":"B. McGregor, K. Butler","doi":"10.1071/EA06308","DOIUrl":"https://doi.org/10.1071/EA06308","url":null,"abstract":"Differences in cashmere production and fleece attributes associated with farm of origin, age and sex were quantified for commercial Australian cashmere goat enterprises. From 11 farms in four states, 1147 does and 97 wethers were monitored, representing 1- to 13-year-old goats. Individual clean cashmere production ranged from 21 to 389 g, with a mean ± standard deviation value of 134 ± 62 g. The mean cashmere production of 2-year-old does from different farms varied from 69 to 225 g and averaged 141 g. Mean ± s.d. greasy fleece weight was 394 ± 123 g, clean washing yield was 90.8 ± 4.1%, clean cashmere yield 33.4 ± 9.4%, cashmere fibre diameter 16.4 ± 1.6 µm, fibre curvature 48 ± 8.7 degrees/mm and staple length 8.7 ± 2.1 cm. There were large, commercially significant differences between farms for clean cashmere weight, mean fibre diameter and other attributes of cashmere. These were much larger than the effects of age and sex. Farm and age accounted for 42 to 67% of the variation in clean cashmere production, mean fibre diameter, fibre curvature, staple length and clean washing yield. Farm of origin affected clean cashmere yield, accounting for 24% of the variation. Sex of the goats had only a minor effect on the staple length of cashmere. The responses to age of clean cashmere weight, mean fibre diameter and the inverse of fibre curvature are very similar. Generally, cashmere production and mean fibre diameter increased with age. For the majority of farms, cashmere fibre curvature declined in a curvilinear manner with increases in age of goat. There were large differences in cashmere staple length from different farms, with means ranging from 7 to 12 cm. Between 1 and 2 years of age, the staple length of cashmere demonstrated a constant proportional increase. At ages older than 2 years, staple length either declined or increased by less than 1 cm with age, depending on the farm of origin. This study demonstrates that there are large gains in productivity that can be achieved from Australian cashmere goats. A better understanding of on-farm factors that influence cashmere production would enable all producers to optimise their production systems.","PeriodicalId":8636,"journal":{"name":"Australian Journal of Experimental Agriculture","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1071/EA06308","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"58788783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The occurrence and severity of grass toxicoses in Australian alpaca (Vicugna pacos) herds","authors":"Natália G. Sampaio, M. Gishen, K. Reed, Melessa Brown, D. Gregory, K. Munyard","doi":"10.1071/EA06325","DOIUrl":"https://doi.org/10.1071/EA06325","url":null,"abstract":"A survey of 108 alpaca producers registered with the Australian Alpaca Association examined the occurrence and severity of ‘staggers’ (a colloquial term embracing various diseases of the nervous system in animals, characterised by neck tremors and head nodding in the milder alpaca cases and a lack of coordination in moving, a staggering gait and frequent falling in severe cases) in Australian alpaca and the presence of four pasture grasses, during three production seasons in 2004–2006. There have been few studies on the susceptibility of alpaca to staggers and its effect on productivity and animal welfare. The survey found that 23% of alpaca producers had observed staggering animals, with Victoria and South Australia being the most severely affected states. Clinical signs of staggers were most frequent in January–March, with a mean duration of 3 months. Some animals showed clinical signs lasting up to 12 months. A strong correlation was found between the presence of perennial ryegrass (P < 0.001) and phalaris (P < 0.003) and the occurrence of staggers. Based on grass presence and the timing when staggers was observed, it was concluded that perennial ryegrass toxicosis was the main cause of staggers in alpaca. About 12% and 9% of alpaca grazing pasture containing perennial ryegrass exhibited staggers in the two full seasons for which data were collected. Herds with staggering animals were correlated with those exhibiting possible subclinical effects – heat sensitivity and ill-thrift (P < 0.01) and reduced fertility (P < 0.05) – of perennial ryegrass endophyte toxins. Results indicate that weanlings and cria are more likely to stagger than adults. Thirteen of the 15 mixed farms with staggering alpaca did not observe staggers in other livestock, suggesting that alpaca may be more sensitive to the causal toxins than sheep and cattle.","PeriodicalId":8636,"journal":{"name":"Australian Journal of Experimental Agriculture","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"58789303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dietary cation–anion differences in some pasture species, changes during the season and effects of soil acidity and lime amendment","authors":"S. Pelletier, R. Simpson, R. Culvenor, G. Bélanger, G. Tremblay, G. Allard, J. Braschkat, P. Randall","doi":"10.1071/EA08121","DOIUrl":"https://doi.org/10.1071/EA08121","url":null,"abstract":"The difference between cation and anion concentrations is an important property when assessing feed for dry dairy cows in order to avoid hypocalcaemia following calving. Dietary cation–anion difference (DCAD) is used to assess suitability of feed and predict the risk of milk fever; a value of –5 cmol(+)/kg dry matter (DM) or less is desirable. This work has examined the DCAD of 16 field-grown species found in pasture in southern Australia. The DCAD [cmol(+)/kg DM] at the flowering stage varied from 7 to 32 for grasses, 21 to 72 for legumes and 72 to 99 for dicot weeds. The average DCAD for legumes was 50 cmol(+)/kg DM, over 2-fold higher than the 20 cmol(+)/kg DM average for grasses. There was a substantial decline in DCAD of herbage as the season progressed. In a glasshouse experiment with five grass species in an acid soil, lime application increased yield and tended to lower the DCAD. Lime decreased uptake per unit root length of potassium and chlorine and increased uptake of calcium by phalaris and timothy. While DCAD is an important attribute of herbage for assessing its suitability for prepartum diets of dairy cows, the present data indicate that it would be prudent to also consider concentrations of calcium and other mineral nutrients in herbage, particularly when examining less familiar plant species or the effects of different cultural practices on the composition of herbage for such diets.","PeriodicalId":8636,"journal":{"name":"Australian Journal of Experimental Agriculture","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"58805214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Designing complex research projects to estimate genetic parameters plus treatment and other effects – optimising the experimental design","authors":"D. L. Robinson","doi":"10.1071/EA07356","DOIUrl":"https://doi.org/10.1071/EA07356","url":null,"abstract":"There is an increasing trend towards integrated research, in which several individuals or institutions pool their expertise and make use of common resources, collaborating towards a common set of scientific goals. Integrated research enables a larger number of factors to be investigated, and the most influential or important ones identified, providing information on how the different factors interact or fit together. Good experimental design is, however, required to ensure the aims can be achieved and resources spent wisely. Issues involved in the experimental design of the Australian Beef Cattle Cooperative Research Centre for Meat Quality are discussed. Theoretical results and simulation studies were used to determine optimal numbers of progeny per sire for estimating genetic parameters. For heritabilities of 0.2 and 0.5, the optima are respectively 21 and 9 progeny with recorded measurements. The curves surrounding the optima are quite flat, so aiming for 10–15 progeny with measurements per trait should provide reasonable accuracy in many situations. Estimates of heritabilities, genetic correlations and phenotypic variances have lower sampling correlations than genetic variances and covariances, suggesting that when results are pooled over different breeds or trials, it is better to pool estimates of heritabilities and genetic correlations than (co)variances. Using sires in more than one year increases the robustness of estimated sire effects and increases the accuracy of genetic parameter estimates for hard-to-measure traits (e.g. feed efficiency) that are not recorded on all animals. Unless sires can be chosen as a true random sample of the population, arrangements of link sires (and other effects such as treatments) should be chosen to provide accurate estimates when all terms in the model are fitted as fixed.","PeriodicalId":8636,"journal":{"name":"Australian Journal of Experimental Agriculture","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"58797673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of rumen microbial genome information to livestock systems in the postgenomic era","authors":"G. Attwood, W. Kelly, E. Altermann, C. Moon, S. Leahy, A. Cookson","doi":"10.1071/EA07408","DOIUrl":"https://doi.org/10.1071/EA07408","url":null,"abstract":"Sequencing the genomes of individual rumen microbes and determining the function of their encoded genes promises to transform our understanding of the microbiology of the rumen. The diversity and density of microbes in the rumen, and our inability to culture the majority of rumen microbes, limit current genome studies to only a small fraction of the microbes present in this environment. Nevertheless, genomes of fibre-degrading organisms are beginning to reveal a previously unexpected abundance of genes encoding glycosyl hydrolases and carbohydrate esterases, which could be used to enhance fibre digestion in the rumen. Additionally, genome sequencing of a rumen methanogen is identifying conserved genes within the methanogenic archaea that may serve as targets for their inhibition and therefore reduction of methane emissions from ruminants. The problem of rumen microbe culturability can be overcome by a new approach called metagenomics, in which microbial DNAs are extracted from rumen samples and sequenced independent of cultivation. In the future, sequencing individual genomes and metagenomic libraries is likely to capture much more of the microbial DNA in the rumen and, coupled with postgenomic studies on gene and protein expression, is likely to enhance our knowledge of the microbial component of ruminant digestion.","PeriodicalId":8636,"journal":{"name":"Australian Journal of Experimental Agriculture","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"58798588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In utero effects on livestock muscle development and body composition","authors":"J. Brameld, Z. Daniel","doi":"10.1071/EA08017","DOIUrl":"https://doi.org/10.1071/EA08017","url":null,"abstract":"This review will focus on the evidence for in utero effects on development of skeletal muscle in farm and laboratory animals, particularly sheep and pigs. We will describe genetic and environmental factors that have been shown to alter the numbers of muscle fibres formed and outline our working hypothesis for the mechanism involved and the critical window during pregnancy when these effects are seen. We will then discuss the long-term consequences in terms of body composition. Although this review concentrates on skeletal muscle development, the mechanism we suggest might be equally applicable to other tissues in the body (e.g. the brain, kidneys or sex organs) and, therefore, impact on their physiological functions.","PeriodicalId":8636,"journal":{"name":"Australian Journal of Experimental Agriculture","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1071/EA08017","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"58800974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effect of finishing diet and meat cuts on the attributes of four processed products from bull beef","authors":"M. Farouk, C. Podmore, C. Boom, G. Sheath","doi":"10.1071/EA07395","DOIUrl":"https://doi.org/10.1071/EA07395","url":null,"abstract":"Breakfast beef, stir-fry, pot-roast and oven-roast meats were prepared from the brisket, clod, inside round and knuckle of bulls on two pasture-based finishing diets (6 weeks of grain supplement before slaughter or no supplement). Diet affected the fatness of the raw meat but had no significant effect on the attributes assessed by the in-house consumer or trained panel. Stir fry from brisket, and pot roast and oven roast from brisket and clod, had higher (P knuckle > inside round > brisket; and that of product acceptability with appropriate processing was breakfast beef > oven roast > pot roast > stir fry. Female in-house consumer panellists assigned lower acceptability scores to the beef products than their male counterparts (P < 0.05). Because none of the muscles or products made from the muscles were totally rejected by the consumer panel (overall scores range from 4.2 to 7.0), there is potential to add value to these cuts through further processing.","PeriodicalId":8636,"journal":{"name":"Australian Journal of Experimental Agriculture","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1071/EA07395","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"58798145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development and validation of a simple technique for logging body temperature in free-ranging cattle","authors":"J. Lea, D. Niemeyer, M. Reed, A. Fisher, D. Ferguson","doi":"10.1071/EA07422","DOIUrl":"https://doi.org/10.1071/EA07422","url":null,"abstract":"This series of experiments was undertaken to develop a low animal impact, inexpensive and simple method of continuous logging of body temperature in free-ranging adult cattle for periods up to 7 days. Two different types of logger (iButton and Vemco minilogger) and three different methods of attachment (surgical implant, anal girth strap and anal tail attachment) for the iButton were investigated. The technique based on the iButton temperature logger, secured to the tail head was the most effective. This technique required minimal animal handling and provided reliable and accurate measurement of temperature in freely behaving cattle.","PeriodicalId":8636,"journal":{"name":"Australian Journal of Experimental Agriculture","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1071/EA07422","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"58800011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genotype and age effects on sheep meat production. 5. Lean meat and fat content in the carcasses of Australian sheep genotypes at 20-, 30- and 40-kg carcass weights","authors":"E. Ponnampalam, K. Butler, D. Hopkins, M. Kerr, F. Dunshea, R. Warner","doi":"10.1071/EA08054","DOIUrl":"https://doi.org/10.1071/EA08054","url":null,"abstract":"Leanmeatand fat content of Australiansheep genotypes were comparedat20-,30- and 40-kg carcass weights. Sheep comprised Poll Dorsetgrowth ·Border Leicester Merino (PDg ·BLM), Poll Dorsetgrowth ·Merino (PDg ·M), Poll Dorsetmuscling ·Merino (PDm ·M), Border Leicester ·Merino (BL ·M) and Merino ·Merino (M ·M) genotypes. Lambs wereraisedasamixedflockundergrazingandslaughteredat4,8,14and22monthsofagewitheachslaughtertimeinvolving ~150mixed sex animals. At 24h after slaughter, chilled carcasses were halved along the backbone and the right sides were usedfordeterminationoflean,fatandashpercentagesusingdualenergyX-rayabsorptiometry.Withinaparticularagegroup andgenotype,animalsgrowingatfasterratesandreachingheaviercarcassweightshadlowercarcassleanmeatcontentthan slowergrowinganimals.Merinocarcassesweighing20and30kghadsimilarlevelsofleanmeattoPD ·Mgenotypes,which wasgreaterthanthatfromtheBL ·Mgenotype.Second-crossPD ·BLMcarcassesweighing20kgat4monthsand30kgat 8monthshadsimilarcarcassfatandleanpercentagesto20-kgMerinocarcassesat8monthsandfirst-crossPD ·Mcarcasses weighing30kgat14 months, respectively. At40-kgcarcass weight, 22-month-oldMerinoshad similarlevelsofleannessto carcasses from 22-month-old PD ·M animals and carcasses from 14-month-old second-cross PD ·BLM animals. Carcass leanmeatcontentdecreasedwithincreasingcarcassweightandfirst-crossBL ·Manimalshadthelowestcarcassleanacross allweightcategories.Therewasamajoraccelerationincarcassfatnessbetween14and22monthsassociatedwithareduction inmuscle deposition.Results indicatethatage ofthe animalshouldbe taken intoaccount whencarcass leanand fat contents are compared at a particular carcass weight. Merinos will achieve weight/composition specifications at least equally well to crossbreds but will take longer with a likely increase in production costs.","PeriodicalId":8636,"journal":{"name":"Australian Journal of Experimental Agriculture","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1071/EA08054","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"58803061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}