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Articles de revues sur le sujet « Merino sheep Breeding Australia »

Auteur : Grafiati

Publié le 4 juin 2021

Mis à jour le 29 janvier 2023

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1

RAADSMA, H. W., G. D. GRAY, and R. R. WOOLASTON. "Breeding for disease resistance in Merino sheep in Australia." Revue Scientifique et Technique de l'OIE 17, no. 1 (April 1, 1998): 315–28. http://dx.doi.org/10.20506/rst.17.1.1103.

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Cottle, D. J., M. T. Harrison, and A. Ghahramani. "Sheep greenhouse gas emission intensities under different management practices, climate zones and enterprise types." Animal Production Science 56, no. 3 (2016): 507. http://dx.doi.org/10.1071/an15327.

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Greenhouse gas emissions (GHG) from broadacre sheep farms constitute ~16% of Australia’s total livestock emissions. To study the diversity of Australian sheep farming enterprises a combination of modelling packages was used to calculate GHG emissions from three sheep enterprises (Merino ewe production for wool and meat, Merino-cross ewes with an emphasis on lamb production, and Merino wethers for fine wool production) at 28 sites across eight climate zones in southern Australia. GHG emissions per ha, per dry sheep equivalents and emissions intensity (EI) per tonne of clean wool or liveweight s

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Lakota, E. А. "PRESERVATION OF GENETIC POTENTIAL OF STAVROPOL SHEEP BREED FOR POVOLZHYE DREY STEPPE ZONE." Vestnik of Ulyanovsk state agricultural academy, no. 3(50) (September 8, 2020): 179–84. http://dx.doi.org/10.18286/1816-4501-2020-3-179-184.

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In conditions of Povolzhye steppe zone development of productive qualities of Stavropol breed sheep was conducted by meat merino sheep. Experimental research was carried out in ZAO «Novaya Zhizn» in Novouzensky district of Saratov region, located in semi desert zone, bordering upon South-West Khazakhstan. The research aim was the increase and maintenance of genetic potential of Stavropol breed sheep of Povolzhye population. Working procedure is based on guidelines of the All-Union Academy of Agricultural sciences, All Union research institute of sheep and goat breeding. The study materials wer

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Wilkes, M. J., P. I. Hynd, and W. S. Pitchford. "Damara sheep have higher digestible energy intake than Merino sheep when fed low-quality or high-quality feed." Animal Production Science 52, no. 1 (2012): 30. http://dx.doi.org/10.1071/an11033.

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The use of animals that are resilient to challenging environments is becoming of increasing importance in animal production systems. Interest in breeds of sheep such as the Damara for sheep meat production is increasing in Australia. Anecdotally this breed outperforms the traditionally grazed Merino in the harsh rangeland environments encountered in the Pastoral Zone of Australia, but little evidence is available to support this claim. A trial was conducted to quantify differences in the efficiency of feed utilisation and growth performance of Damara and Merino sheep under two contrasting diet

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Williams, A. R., L. J. E. Karlsson, D. G. Palmer, P. E. Vercoe, I. H. Williams, J. C. Greeff, and D. L. Emery. "Faecal dry matter and nematode infection in parasite-resistant Merino sheep in Australia." Proceedings of the British Society of Animal Science 2009 (April 2009): 29. http://dx.doi.org/10.1017/s1752756200028684.

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Scouring (diarrhoea) is a major concern for sheep producers as the accumulation of faecal material (dags) around the breech pre-disposes sheep to flystrike. Scouring occurs when the consistency of faeces is fluid with a low percentage of dry matter. In temperate areas such as the southern half of Australia, New Zealand and the United Kingdom, scouring is associated with ingestion of parasitic nematode larvae, mainly Teladorsagia circumcincta and Trichostrongylus colubriformis (Larsen et al., 1994). Breeding sheep to be resistant to these nematodes is a sustainable parasite-control strategy due

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Brown, D. J., and N. M. Fogarty. "Genetic relationships between internal parasite resistance and production traits in Merino sheep." Animal Production Science 57, no. 2 (2017): 209. http://dx.doi.org/10.1071/an15469.

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Breeding Merino sheep that are resistant to internal parasites alleviates the high costs associated with treatment of worm infestation and loss of production, as well as mitigating the development of anthelmintic resistance among the major worm species. Faecal worm egg count ((cube root transformation), wec) can be used in sheep as a measure of internal parasite resistance. Accurate estimates of genetic parameters for wec are required for calculation of Australian Sheep Breeding Values and inclusion of worm resistance in sheep breeding programs. This study provides updated estimates of heritab

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Daetwyler, H. D., J. M. Hickey, J. M. Henshall, S. Dominik, B. Gredler, J. H. J. van der Werf, and B. J. Hayes. "Accuracy of estimated genomic breeding values for wool and meat traits in a multi-breed sheep population." Animal Production Science 50, no. 12 (2010): 1004. http://dx.doi.org/10.1071/an10096.

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Estimated breeding values for the selection of more profitable sheep for the sheep meat and wool industries are currently based on pedigree and phenotypic records. With the advent of a medium-density DNA marker array, which genotypes ~50 000 ovine single nucleotide polymorphisms, a third source of information has become available. The aim of this paper was to determine whether this genomic information can be used to predict estimated breeding values for wool and meat traits. The effects of all single nucleotide polymorphism markers in a multi-breed sheep reference population of 7180 individual

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Mortimer, S. I., K. D. Atkins, S. J. Semple, and N. M. Fogarty. "Predicted responses in Merino sheep from selection combining visually assessed and measured traits." Animal Production Science 50, no. 10 (2010): 976. http://dx.doi.org/10.1071/an10085.

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Visually assessed traits for wool quality and ease of management are important to Merino sheep breeders and need to be considered in breeding programs. The present study reports on the predicted correlated responses in visual traits from selection using a range of standard MERINOSELECT™ indices available for use in Australian Merino breeding programs. The effect of including a visual trait in the index is also reported. The visual scored traits were classer grade, wool quality (handle, character and colour), conformation (neck and body wrinkle, front and back leg structure) and fleece rot. The

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Blumer, S. E., G. E. Gardner, M. B. Ferguson, and A. N. Thompson. "Environmental and genetic factors influence the liveweight of adult Merino and Border Leicester × Merino ewes across multiple sites and years." Animal Production Science 56, no. 4 (2016): 775. http://dx.doi.org/10.1071/an14419.

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Variation in liveweight change in the ewe flock during periods of poor nutrition can affect farm profitability through the effects of liveweight loss on potential stocking rate, management interventions including supplementary feeding, and ewe and lamb survival and productivity. There is variation between individual animals in their ability to manage periods of poor nutrition, but the links between liveweight change and breeding values in the adult ewe flock have not been quantified. We analysed 5216 liveweight profiles for 2772 ewes managed over 3 years at eight sites across Australia, to def

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Swan, Andrew A., Daniel J. Brown, and Julius H. J. van der Werf. "Genetic variation within and between subpopulations of the Australian Merino breed." Animal Production Science 56, no. 1 (2016): 87. http://dx.doi.org/10.1071/an14560.

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Genetic variation within and between Australian Merino subpopulations was estimated from a large breeding nucleus in which up to 8500 progeny from over 300 sires were recorded at eight sites across Australia. Subpopulations were defined as genetic groups using the Westell–Quaas model in which base animals with unknown pedigree were allocated to groups based on their flock of origin if there were sufficient ‘expressions’ for the flock, or to one of four broad sheep-type groups otherwise (Ultra/Superfine, Fine/Fine-medium, Medium/Strong, or unknown). Linear models including genetic groups and ad

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Behrendt, Karl. "Price risk exposure of Australian Merinos – is it in the bloodline?" Animal Production Science 54, no. 9 (2014): 1317. http://dx.doi.org/10.1071/an14305.

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Sheep producers and their advisors utilise Australian Merino bloodline trial data to guide future sheep breeding objectives and ram selection. To adequately assess the economic outcomes from different bloodlines in the decision making process, there is a need to consider the impact of wool and sheep meat price risk. Using a steady-state wether flock model that accounts for the lifetime productivity of 268 reported Merino bloodlines and stochastic dependency in weekly wool and sheep meat prices from 28 June 2005 to 10 November 2011, gross incomes per dry sheep equivalent (GI/DSE) were calculate

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Granleese, T., S. A. Clark, A. A. Swan, and J. H. J. van der Werf. "Increased genetic gains in multi-trait sheep indices using female reproductive technologies combined with optimal contribution selection and genomic breeding values." Animal Production Science 57, no. 10 (2017): 1984. http://dx.doi.org/10.1071/an15440.

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Female reproductive technologies such as multiple ovulation and embryo transfer (MOET) and juvenile in vitro fertilisation and embryo transfer (JIVET) can produce multiple offspring per mating in sheep and cattle. In breeding programs this allows for higher female selection intensity and, in the case of JIVET, a reduction in generation interval, resulting in higher rates of genetic gain. Low selection accuracy of young females entering JIVET has often dissuaded producers from using this technology. However, genomic selection (GS) could increase selection accuracy of candidates at a younger age

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Salvatore, L., D. Allen, K. L. Butler, D. Tucman, A. Elkins, D. W. Pethick, and F. R. Dunshea. "Factors affecting the concentration of short branched-chain fatty acids in sheep fat." Australian Journal of Experimental Agriculture 47, no. 10 (2007): 1201. http://dx.doi.org/10.1071/ea07037.

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The concentration of short branched-chain fatty acids, specifically 4-methyloctanoic acid (MOA) and 4-methylnonanoic acid (MNA), in subcutaneous fat were determined in five genotypes (Poll Dorset × Border Leicester Merino, Poll Dorset × Merino, Poll Dorsetmuscling × Merino, Merino × Merino, Border Leicester × Merino) of Australian sheep. In total, 264 ewes and wethers, either 8 or 22 months of age, were selected for genotype, age and gender. These animals were sired by 16 rams that were selected for growth based on estimated breeding values (EBVs), except for one group (Poll Dorsetmuscling × M

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Fogarty, N. M., E. Safari, P. J. Taylor, and W. Murray. "Genetic parameters for meat quality and carcass traits and their correlation with wool traits in Australian Merino sheep." Australian Journal of Agricultural Research 54, no. 7 (2003): 715. http://dx.doi.org/10.1071/ar03047.

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Estimates of genetic parameters for carcass traits in Merino sheep are presented, including muscle pH and colour, which are indicators of meat quality. The inclusion of these in the parameter set for genetic evaluation will provide the basis for more accurate estimated breeding values and the design of better breeding programs for improving meat traits in straightbred Merino sheep and crossbred lamb production. Data from 1045, nineteen-month-old Merino rams, the progeny of 125 sires from 3 strains that are representative of the industry, were used. Heritability and genetic correlations were es

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Mortimer, S. I., J. H. J. van der Werf, R. H. Jacob, D. W. Pethick, K. L. Pearce, R. D. Warner, G. H. Geesink, et al. "Preliminary estimates of genetic parameters for carcass and meat quality traits in Australian sheep." Animal Production Science 50, no. 12 (2010): 1135. http://dx.doi.org/10.1071/an10126.

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Using performance from progeny born in 2007 and 2008 generated by the Information Nucleus program of the Cooperative Research Centre for Sheep Industry Innovation, preliminary estimates of heritability were obtained for a range of novel carcass and meat attributes of lamb relevant to consumers, including carcass characteristics, meat quality and nutritional value of lamb. Phenotypic and genetic correlations of live animal traits with carcass composition and meat quality traits were also estimated. The data were from progeny located at eight sites, sired by 183 rams from Merino, maternal and te

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Qiu, Xiaoyan, Xiong Xiao, Nan Li, Wenhui Ling, Mingyu Wang, and Yuemin Li. "Association of steroid 17-alpha-hydroxylase/17,20 lyase (CYP17) single nucleotide polymorphism (SNP) 628 and dopamine receptor D2 (DRD2) SNP939 genotypes with sheep reproductive performance." Reproduction, Fertility and Development 31, no. 4 (2019): 743. http://dx.doi.org/10.1071/rd18069.

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In a previous study we investigated the association between two single nucleotide polymorphism (SNP) genotypes, namely steroid 17-alpha-hydroxylase/17,20 lyase (CYP17) SNP628 and dopamine receptor D2 (DRD2) SNP939, with two temperaments (calm and nervous) in Australian Merino sheep and concluded that the DRD2 SNP939 T/T genotype combined with the CYP17 SNP628 G/G genotype is associated with a calm temperament and could be used as a potential marker for calm sheep, whereas the DRD2 SNP939C allele combined with the CYP17 SNP628 A/A genotype is associated with a nervous temperament and could be u

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Aboneev, Vasily, Dmitry Aboneev, Ekaterina Aboneeva, Safarbi Kazanchev, and Dastanbek Baimukanov. "Results of using different breed studs in commercial fine wool sheep breeding." E3S Web of Conferences 262 (2021): 02016. http://dx.doi.org/10.1051/e3sconf/202126202016.

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This work presents the material of research and production experiments on the crossing of stud rams of the North Caucasian meat and wool breed and Australian meat merino with fine wool ewes of a commercial herd. It is identified that the use of North Caucasian rams on fine wool ewes serves to increase the fertilizing ability and milk production of the breeding stock, to increase viability and resistance of young animals, as confirmed by the best morphometrical differences of crossbred offspring placentas. Crossbred offspring from semi-fine wool rams had a large live weight at birth at 21 days

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Sahana, G., S. C. Gupta, and A. E. Nivsarkar. "Garole: The prolific sheep of India." Animal Genetic Resources Information 31 (April 2001): 55–63. http://dx.doi.org/10.1017/s1014233900001486.

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SummaryA survey on Garole sheep was carried out in the breeding tract for breed characterization. Garole sheep are distributed in the Sundarban region of West Bengal in India. It is a small-sized breed known for its prolificacy and adaptation to the saline marshy land of the Sundarban region. It is believed that these sheep contributed to the prolificacy gene in Booroola Merino sheep of Australia. The breeding tract of Garole sheep falls under the Coastal Saline Zone of West Bengal and the climate of this region is hot and humid. The population of Garole sheep was 206 720 in 1994–1995. This br

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Walkom, S. F., F. D. Brien, M. L. Hebart, S. I. Mortimer, and W. S. Pitchford. "Season and reproductive status rather than genetics factors influence change in ewe weight and fat over time. 3. Analysis of Merino ewes." Animal Production Science 54, no. 6 (2014): 821. http://dx.doi.org/10.1071/an13249.

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The profitability of southern Australian sheep production systems depends on the optimisation of stocking rates by meeting the nutritional demands of the breeding ewe while effectively utilising grown pasture. The aim of the study was to evaluate the genetic variation in liveweight and body condition of Merino ewes across their breeding life within a wool-based enterprise. The results were consistent with findings in crossbred ewes and showed that the genetic component of weight and body condition remained constant across the production cycle and age. The overall additive genetic effect accoun

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Walkom, S. F., A. N. Thompson, E. Bowen, and D. J. Brown. "Weaner survival is heritable in Australian Merinos and current breeding objectives are potentially leading to a decline in survival." Animal Production Science 59, no. 1 (2019): 35. http://dx.doi.org/10.1071/an17151.

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There is little evidence to show that mortality rates during the period after weaning are improving over time in Australian sheep. The average mortality rate of Merino lambs during the post-weaning period has been estimated to be 5.2%. The present study explored the potential for producers to breed for improved survival rates during the post-weaning period and the potential impact this would have on key production traits. A total of 122526 weaner survival (mortality) records were obtained from 18 Merino flocks, between 1989 and 2014, encompassing a wide variety of Australian Merino sheep types

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Ponnampalam, E. N., D. L. Hopkins, K. L. Butler, F. R. Dunshea, and R. D. Warner. "Genotype and age effects on sheep meat production. 2. Carcass quality traits." Australian Journal of Experimental Agriculture 47, no. 10 (2007): 1147. http://dx.doi.org/10.1071/ea07001.

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The present study examines carcass quality traits in different genotypes of Australian sheep slaughtered at 4, 8, 14 and 22 months of age. Poll Dorsetgrowth × Border Leicester Merino (PDg × BLM), Poll Dorsetgrowth × Merino (PDg × M), Poll Dorsetmuscling × Merino (PDm × M), Merino × Merino (M × M) and Border Leicester × Merino (BL × M) genotypes were compared. Sires were selected on the basis of growth (PDg, M and BL) and muscle (PDm) using estimated breeding values (EBVs). Approximately 150 mixed sex animals were slaughtered at each age (595 in total for the four slaughters) and carcass qualit

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Moghaddar, N., A. A. Swan, and J. H. J. van der Werf. "Genomic prediction of weight and wool traits in a multi-breed sheep population." Animal Production Science 54, no. 5 (2014): 544. http://dx.doi.org/10.1071/an13129.

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The objective of this study was to predict the accuracy of genomic prediction for 26 traits, including weight, muscle, fat, and wool quantity and quality traits, in Australian sheep based on a large, multi-breed reference population. The reference population consisted of two research flocks, with the main breeds being Merino, Border Leicester (BL), Poll Dorset (PD), and White Suffolk (WS). The genomic estimated breeding value (GEBV) was based on GBLUP (genomic best linear unbiased prediction), applying a genomic relationship matrix calculated from the 50K Ovine SNP chip marker genotypes. The a

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Butler, LG, SR Corkrey, IJ Knox, G. Hannan, and RP Thomson. "Perceptions and knowledge of measurement in selection programs: a survey of stud Merino breeders in Australia." Australian Journal of Experimental Agriculture 35, no. 6 (1995): 681. http://dx.doi.org/10.1071/ea9950681.

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A total of 329 (25%) stud Merino breeders returned a survey designed to evaluate their knowledge of, and attitudes to, objective measurement in sheep breeding and performance recording. The data were analysed by log-linear regression techniques. There was overwhelming agreement that performance records were not as valid as traditional methods, but there was general agreement that measurement improves accuracy of selection, increases genetic gain, assists ram buyers and breeders, and increases flock earnings. There is a significant concern regarding the accuracy of fleece tests. Most respondent

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Ponzoni, R. W. "A profit equation for the definition of the breeding objective of Australian merino sheep." Journal of Animal Breeding and Genetics 103, no. 1-5 (January 12, 1986): 342–57. http://dx.doi.org/10.1111/j.1439-0388.1986.tb00096.x.

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Sawyer, Gregory, Danielle Webster, and Edward Narayan. "Measuring wool cortisol and progesterone levels in breeding maiden Australian merino sheep (Ovis aries)." PLOS ONE 14, no. 4 (April 8, 2019): e0214734. http://dx.doi.org/10.1371/journal.pone.0214734.

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Eady, S. J., R. R. Woolaston, R. W. Ponzoni, R. P. Lewer, H. W. Raadsma, and A. A. Swan. "Resistance to nematode parasites in Merino sheep: correlation with production traits." Australian Journal of Agricultural Research 49, no. 8 (1998): 1201. http://dx.doi.org/10.1071/a98069.

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Merino sheep representing a range of bloodlines in resource flocks located across Australia were tested for resistance to gastro-intestinal nematodes. These flocks included the JB Pye Flock (Camden, NSW), Katanning Base Flock (Katanning, WA), Turretfield Merino Resource Flock (Rosedale, SA), and the CSIRO Finewool Flock (Armidale, NSW) and included a total of 328 sire groups. Resistance to nematodes was measured by faecal egg count (FEC). Data were also available for greasy and clean fleece weight (GFW and CFW, respectively), fibre diameter (FD), and body weight (BW) at a range of ages from we

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Benavides, M. V., S. Damak, and A. P. Maher. "A putative resistant DNA marker for wool yellowing susceptibility in sheep." Genetics and Molecular Biology 23, no. 2 (June 2000): 341–46. http://dx.doi.org/10.1590/s1415-47572000000200017.

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An Australian Merino flock was screened for low (resistant) and high (susceptible) yellow predictive colour (YPC) breeding values in order to compare extreme individuals using the differential display of mRNA technique. One differentially expressed cDNA band was visualised only in the resistant group. This band showed no identity with the DNA sequences of public databases; however, they showed short homologies with three database sequences related to transmembrane signalling functions. The use of these candidate genes as DNA markers needs to be confirmed against sheep with a wide range of susc

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Huisman, A. E., D. J. Brown, A. J. Ball, and H. U. Graser. "Genetic parameters for bodyweight, wool, and disease resistance and reproduction traits in Merino sheep. 1. Description of traits, model comparison, variance components and their ratios." Australian Journal of Experimental Agriculture 48, no. 9 (2008): 1177. http://dx.doi.org/10.1071/ea08119.

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Both wool and sheep meat industries are interested in sheep that have a high reproduction performance and are resistant to internal parasites, in addition to the traditional traits. There is considerable interest in breeding sheep for wool, carcass, reproductive and internal parasite resistance traits simultaneously. The objective of this study was to estimate single trait genetic parameters for 40 traits recorded in Merino sheep, covering bodyweight, carcass, wool, reproduction and internal parasite resistance traits. This also involved determining the appropriate models. The results from thi

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Newton, J. E., D. J. Brown, S. Dominik, and J. H. J. van der Werf. "Impact of young ewe fertility rate on risk and genetic gain in sheep-breeding programs using genomic selection." Animal Production Science 57, no. 8 (2017): 1653. http://dx.doi.org/10.1071/an15321.

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Genomic selection could be useful in sheep-breeding programs, especially if rams and ewes are first mated at an earlier age than is the current industry practice. However, young-ewe (1 year old) fertility rates are known to be lower and more variable than those of mature ewes. The aim of the present study was to evaluate how young-ewe fertility rate affects risk and expected genetic gain in Australian sheep-breeding programs that use genomic information and select ewes and rams at different ages. The study used stochastic simulation to model different flock age structures and young-ewe fertili

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Safari, E., N. M. Fogarty, A. R. Gilmour, K. D. Atkins, S. I. Mortimer, A. A. Swan, F. D. Brien, J. C. Greeff, and J. H. J. van der Werf. "Across population genetic parameters for wool, growth, and reproduction traits in Australian Merino sheep. 1. Data structure and non-genetic effects." Australian Journal of Agricultural Research 58, no. 2 (2007): 169. http://dx.doi.org/10.1071/ar06161.

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Accurate estimates of adjustment factors for systematic environmental effects are required for genetic evaluation systems. This study combined data from 7 research resource flocks across Australia to estimate genetic parameters and investigate the significance of various environmental factors for production traits in Australian Merino sheep. The flocks were maintained for several generations and represented contemporary Australian Merino fine, medium, and broad wool bloodlines over the past 30 years. Over 110 000 records were available for analysis for each of the major wool traits, with over

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Bray, M., D. K. Revell, C. S. Bawden, and P. I. Hynd. "Keratin gene expression in Merino sheep with divergent wool growth." Australian Journal of Agricultural Research 56, no. 3 (2005): 203. http://dx.doi.org/10.1071/ar03253.

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South Australian Merino sheep were selected on the basis of high or low estimated breeding values (EBV) for wool growth rate (W), but with similar bodyweight, follicle density, and mean fibre diameter. Differences in the level of expression of keratin genes were examined in the skin of these sheep to test the hypothesis that divergence in EBV for wool growth is related to the production of wool proteins differing in sulfur (S) content. Further, it was proposed that this differential gene expression would be most pronounced when the supply of S amino acids to the animal was increased. Sheep sel

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Ferguson, M. B., J. M. Young, G. A. Kearney, G. E. Gardner, I. R. D. Robertson, and A. N. Thompson. "The value of genetic fatness in Merino ewes differs with production system and environment." Animal Production Science 50, no. 12 (2010): 1011. http://dx.doi.org/10.1071/an10130.

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Selection against fatness in the Australian sheep industry has been a priority, but defining the true value of fat requires an understanding of the effects it has on both the value of lamb carcasses and on sheep productivity. A Merino flock with 10 years of reproduction data was used to analyse the correlation between breeding values for fatness at yearling age (YFAT) and the number of lambs born per ewe mated (NLB). In 2 production years, NLB was related (P < 0.01) to YFAT resulting in an extra 14 or 24.5 lambs born per 100 ewes mated per mm of YFAT. Based on these relationships, bio-econo

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Fozi, M. Asadi, J. H. J. Van der Werf, and A. A. Swan. "The importance of accounting for maternal genetic effects in Australian fine-wool Merino breeding." Australian Journal of Agricultural Research 56, no. 8 (2005): 789. http://dx.doi.org/10.1071/ar05006.

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(Co) variances for greasy fleece weight (GFW), clean fleece weight (CFW), mean fibre diameter (MFD), staple strength (SS), coefficient of variation of fibre diameter (CVFD), birthweight (BW), weaning weight (WW), and yearling weight (YW) were estimated for 5108 Australian Merino sheep from the CSIRO Fine Wool Project, born between 1990 and 1994. Covariances between these traits and number of lambs weaned per ewe joined (NLW) were also estimated. Significant maternal genetic effects were found for GFW, CFW, BW, WW, and YW. Estimates of heritability were biased upwardly when maternal effects wer

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Wray, N. R., and M. E. Goddard. "MOET breeding schemes for wool sheep 2. Selection for adult fleece traits." Animal Science 59, no. 1 (August 1994): 87–98. http://dx.doi.org/10.1017/s0003356100007534.

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AbstractBenefits of collection of annual versus a single fleece record are investigated for breeding programmes of Australian Merino sheep. Breeding scheme alternatives are based on natural mating (N) or multiple ovulation and embryo transfer (MOET). The breeding objective is assumed to be an adult fleece trait which is expressed annually from a minimum of age 2 years, with a unity genetic correlation between annual records. Initial selection of parents can occur prior to the availability of their adult records, based on records collected at 6,12 or 18 months which have a maximum genetic corre

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Morton, K. M., S. L. Catt, F. K. Hollinshead, W. M. C. Maxwell, and G. Evans. "280LAMBS BORN AFTER IN VITRO EMBRYO PRODUCTION FROM PREPUBERTAL LAMB OOCYTES AND FROZEN-THAWED UNSORTED AND SEX-SORTED SPERMATOZOA." Reproduction, Fertility and Development 16, no. 2 (2004): 260. http://dx.doi.org/10.1071/rdv16n1ab280.

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Developments in sperm sexing technology have resulted in the birth of a number of offspring after IVF of oocytes from adult animals (Johnson LA, 2000 An. Reprod. Sci. 60–61, 93–107). The aim of this study was to combine sperm sexing technology with juvenile breeding. Merino lambs, 2–3 weeks (n=43) were hormone stimulated (Morton KM et al., 2003 Proc. Soc. Reprod. Fert., P18), and COCs were matured in TCM-199 (Sigma) with 10μgmL−1 p-FSH (Folltropin-V; Bioniche Animal Health Australasia), 10μgmL−1 pLH (Bioniche), and 20% sheep serum (v/v) in a humidified 6% CO2, 5% O2, 89% N2 atmosphere for 22h.

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Brown, D. J., N. M. Fogarty, C. L. Iker, D. M. Ferguson, D. Blache, and G. M. Gaunt. "Genetic evaluation of maternal behaviour and temperament in Australian sheep." Animal Production Science 56, no. 4 (2016): 767. http://dx.doi.org/10.1071/an14945.

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The temperament of ewes and maternal behaviour at lambing has been implicated as contributing factors to lamb survival. Some 14 054 records of maternal behaviour score (MBS, 1 = good, 5 = poor) were collected at lamb tagging from 32 breeds of sheep over several years in a variety of environments. Records for two objectively scored temperament traits, flight time from a weighing crate (FT) and agitation score in an isolation box test (IBT) were available on 19 151 and 17 159 animals, respectively. These data were pooled from three sources, which included research and commercial ram breeding flo

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Walkom, S. F., and D. J. Brown. "Impact of liveweight, fat and muscle sire breeding values on ewe reproduction is minimal but variable across Australian grazing systems." Animal Production Science 57, no. 9 (2017): 1952. http://dx.doi.org/10.1071/an15574.

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Australian sheep producers have the potential to improve reproductive rates through optimising ewe body condition across the production cycle. Managing ewe body condition can become costly when supplementary feeding is required due to poor pasture growth or rainfall and by using appropriate genetics, producers can theoretically reduce the flock’s dependency on supplementary feed and improve reproductive rates. Reproductive records from the Information Nucleus Flock and Sheep Genetics Merino and maternal breed datasets were analysed to examine the influence of sire breeding values for liveweigh

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Cloete, S. W. P., J. C. Greeff, and R. P. Lewer. "Heritability estimates and genetic and phenotypic correlations of lamb production parameters with hogget liveweight and fleece traits in Western Australian Merino sheep." Australian Journal of Agricultural Research 53, no. 3 (2002): 281. http://dx.doi.org/10.1071/ar00183.

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Heritability estimates (h2) for weight of lamb weaned and number of lambs weaned totalled over 3 reproduction opportunities were estimated in a multi-bloodline Western Australian medium wool resource flock. These traits were defined to give an indication of lifetime lamb production (the ewes were retained in the breeding flock for a maximum of 4 lambing opportunities). Both reproduction traits were highly variable, as suggested by coefficients of variation of approximately 50%. The between-bloodline variance ratio was significant (P < 0.05), but failed to exceed 5% of the total across-blood

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Cottle, DJ. "The derivation of economic values in breeding programs for Australian Merino sheep with changing wool prices and flock production averages." Australian Journal of Agricultural Research 41, no. 4 (1990): 769. http://dx.doi.org/10.1071/ar9900769.

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The impact of fluctuating wool prices on setting economic values (EVs) in selection indices, e.g. WOOLPLAN, are studied by modelling genetic change in a flock following index selection, Operating under different wool price regimes. Because future price changes are difficult to predict, there is no guaranteed, optimal method of determining EVs. One possibility is the use of a moving regression of the last five years' wool prices (in real terms), rather than setting the index once, or every five years, or every year, based on current prices. The ratio (R) of clean wool price to micron premium is

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Khamiruev, T. N. "THE USE OF IMMUNOGENIC MARKERS IN THE SELECTION OF SHEEP OF ZABAIKALSKAYA BREED." Siberian Herald of Agricultural Science 48, no. 4 (October 23, 2018): 87–93. http://dx.doi.org/10.26898/0370-8799-2018-4-12.

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The article presents the results of immunogenic certification of fine-fleece sheep of Zabaikalskaya breed of the Khangil type, bred by a sophisticated reproductive cross-breeding method with Australian and Manych Merino breeds. The animals are adapted to a year-round grazing in harsh climatic conditions. The study was carried out in the pedigree plant of Trans-Baikal Territory. The immunogenic certification of animals was carried out in the laboratory of the immunogenic appraisal by six systems of blood groups including 14 antigenic factors. The blood group characteristics of the young were de

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Hrymak, K. "The sexual activity of the ram-sires, depending on their mode of use." Scientific Messenger of LNU of Veterinary Medicine and Biotechnologies 21, no. 91 (November 6, 2019): 29–32. http://dx.doi.org/10.32718/nvlvet-a9105.

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Literary data are presented and their analysis is conducted regarding the mode of use of ram-sires and their effect on sexual activity and sperm productivity. The results of research of scientists with recommendations of optimal modes of use of fetuses for semen production and its cryopreservation in non-pairing and steaming periods are presented. According to the results of the analysis of many researchers, the activity of the sexual reflexes of the rams in the spring and summer decreases by 1.4 times compared to the winter. At the same time quantitative indicators of sperm productivity decre

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Mortimer, S. I., D. L. Robinson, K. D. Atkins, F. D. Brien, A. A. Swan, P. J. Taylor, and N. M. Fogarty. "Genetic parameters for visually assessed traits and their relationships to wool production and liveweight in Australian Merino sheep." Animal Production Science 49, no. 1 (2009): 32. http://dx.doi.org/10.1071/ea08074.

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Heritability was estimated for a range of visually assessed traits recorded on Merino sheep, together with the phenotypic and genetic correlations among the visually assessed traits and correlations of the visually assessed traits with measured wool production traits and liveweight. Data were derived from four research resource flocks, with a range of 12 958 to 57 128 records from animals with 478 to 1491 sires for the various traits. The estimates of heritability were high for the wool quality traits of handle, wool character and wool colour (0.33–0.34) and the conformation traits of face cov

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Hollema, Baukje L., Piter Bijma, and Julius H. J. van der Werf. "Sensitivity of the breeding values for growth rate and worm egg count to environmental worm burden in Australian Merino sheep." Journal of Animal Breeding and Genetics 135, no. 5 (July 11, 2018): 357–65. http://dx.doi.org/10.1111/jbg.12349.

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Cloete, S. W. P., J. C. Greeff, and R. P. Lewer. "Direct and maternal genetic (co)variances for hogget liveweight and fleece traits in Western Australian Merino sheep." Australian Journal of Agricultural Research 53, no. 3 (2002): 271. http://dx.doi.org/10.1071/ar00184.

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(Co)variance estimates for hogget liveweight, greasy fleece weight, clean fleece weight, clean yield, fibre diameter, and the coefficient of variation of fibre diameter were obtained for a Western Australian Merino resource flock. The flock encompassed 16 medium wool bloodlines and data were available for the period 1982–93. Direct additive genetic variances (h2) — expressed as a ratio of the total phenotypic variance within bloodlines — were estimated at 0.52 for hogget liveweight, 0.44 for greasy fleece weight, 0.42 for clean fleece weight, 0.63 for clean yield, 0.71 for fibre diameter, and

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Brown, D. J., A. A. Swan, and J. S. Gill. "Within- and across-flock genetic relationships for breech flystrike resistance indicator traits." Animal Production Science 50, no. 12 (2010): 1060. http://dx.doi.org/10.1071/an10102.

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Flystrike is a major cost for the Australian sheep industry. The industry is currently implementing selection strategies for flystrike resistance to reduce the need for breech flystrike prevention. The following indicator traits are used to select for breech flystrike resistance: wool cover, skin wrinkle on the body and breech, scouring (dags) and wool colour. The aims of this study were to estimate genetic correlations between these indicator traits and production traits using the Sheep Genetics database, to distinguish between within- and across-flock genetic relationships, and to quantify r

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Paganoni, B. L., M. B. Ferguson, S. Fierro, C. Jones, G. A. Kearney, P. R. Kenyon, C. Macleay, C. Vinoles, and A. N. Thompson. "Early reproductive losses are a major factor contributing to the poor reproductive performance of Merino ewe lambs mated at 8–10 months of age." Animal Production Science 54, no. 6 (2014): 762. http://dx.doi.org/10.1071/an13240.

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The reproductive performance of Merino ewe lambs is lower than that achieved by mature ewes and is highly variable. It is likely that embryo loss represents a major source of reproductive wastage in Merino ewe lambs, but to our knowledge no studies have attempted to determine when the major reproductive losses occur or identify predisposing factors that are likely to lead to high rates of pregnancy failures in ewe lambs. After characterising where reproductive losses occurred in Merino ewe lambs mated at 8–10 months of age, we tested the hypothesis that pregnancy failure in ewe lambs is influe

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Young, J. M., A. N. Thompson, M. Curnow, and C. M. Oldham. "Whole-farm profit and the optimum maternal liveweight profile of Merino ewe flocks lambing in winter and spring are influenced by the effects of ewe nutrition on the progeny's survival and lifetime wool production." Animal Production Science 51, no. 9 (2011): 821. http://dx.doi.org/10.1071/an10078.

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Profitability of sheep production systems in southern Australia is optimised at a stocking rate that provides adequate nutrition for breeding ewes and enables efficient utilisation of grown pasture and supplements. In this paper we used bio-economic modelling to develop optimum liveweight1 profiles for spring-lambing Merino ewes in different environments. The modelling included the impacts of the ewe liveweight profile on the production of the ewe and the survival and lifetime wool production of her progeny. Fifteen ewe liveweight profiles were analysed for each region to determine the profita

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Gonzalez, R. E., D. Labuonora, and A. J. E. Russel. "The effects of ewe live weight and body condition score around mating on production from four sheep breeds in extensive grazing systems in Uruguay." Animal Science 64, no. 1 (February 1997): 139–45. http://dx.doi.org/10.1017/s1357729800015642.

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AbstractEwe live iveights were recorded 4 weeks prior to mating, at the beginning of mating and 22 to 23 days later over a period of 3 years in a flock of some 300 breeding ewes comprising approximately equal numbers of Australian Merino, Ideal (Polwarth), Merilin and Corriedale breeds in a pastorally based grazing system in Uruguay. Multiple-bearing ewes were generally heavier than single-bearing ewes which in turn were heavier than ewes which did not conceive, these differences being greatest in 3- and 4-year-old ewes (i.e. in their second and third breeding seasons). Body condition scores o

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Allingham, P. G., W. Barris, A. Reverter, V. Hilsenstein, R. van de Ven, and D. L. Hopkins. "Sire and growth-path effects on sheep meat production. 3. Fascicular structure of lamb loin muscle (m. longissimus lumborum) and the impact on eating quality." Animal Production Science 49, no. 3 (2009): 239. http://dx.doi.org/10.1071/ea08163.

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The effects of sire genetics and growth path on the fascicular structure (FS) of lamb loin muscle (m. longissimus lumborum; LL) and the consequences for eating quality were studied in progeny (n = 299) of 20 Poll Dorset sires and Merino ewes. Sires were selected on the basis of their Australian sheep breeding values (ASBV) for post-weaning growth (PWWT), loin eye muscle depth (PEMD) and subcutaneous fat (PFAT). Growth of lambs was varied by time of weaning (early or late) and by feeding level within weaning group, where lambs were either fully fed throughout or were feed restricted for 55 days

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Torekhanov, A. A., and N. K. Zhumadillayev. "ETTI MERINOS – KAZAKHSTANI EXPORT-ORIENTED MEAT BREAD." REPORTS 335, no. 1 (February 12, 2021): 146–51. http://dx.doi.org/10.32014/2021.2518-1483.21.

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Sheep breeding in Kazakhstan is a traditional branch of animal husbandry. The development of the industry is facilitated by the presence of large areas of pasture lands, as well as the existing valuable gene pool of breed resources, created by national selection and long-term work of scientists-breeders. The republic has great potential for the further development of sheep breeding industry and is able not only to meet the population's need for mutton, but also to become a major exporter. The restoration and further development of domestic sheep breeding should be based on rational use of gene

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