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A quantitative trait locus (QTL) study of the concentrations of 14 trace and macro elements (minerals) in tissues of beef cattle was conducted in New Zealand. Back-cross calves with Jersey and Limousin ancestry (202 heifers and 211 steers) were generated using first-cross sires. This paper reports on testing for effects of QTL on the concentrations of minerals in liver, kidney and muscle in cattle at slaughter, following a growth phase during which rearing and finishing stages were on pasture. Fifteen QTL were identified (P < 0.05) on a genome-wide basis in combined-sire and within-sire analyses. In addition, the possible effect of the Limousin myostatin F94L allele was tested by fitting each calf's myostatin genotype, and 16 QTL were identified. Twelve were in common with those QTL identified previously, comprising six affecting the liver (copper and zinc, on two chromosomes each; plus iron and molybdenum), three affecting the kidney (calcium, copper and iron), and three affecting muscle (iron, strontium and zinc)., (© 2012 The Authors, Animal Genetics © 2012 Stichting International Foundation for Animal Genetics.)

A QTL study of live animal and carcass traits in beef cattle was carried out in New Zealand and Australia. Back-cross calves (385 heifers and 398 steers) were generated, with Jersey and Limousin backgrounds. This paper reports on weights of eight organs (heart, liver, lungs, kidneys, spleen, gastro-intestinal tract, fat, and rumen contents) and 12 fat composition traits (fatty acid (FA) percentages, saturated and monounsaturated FA subtotals, and fat melting point). The New Zealand cattle were reared and finished on pasture, whilst Australian cattle were reared on grass and finished on grain for at least 180 days. For organ weights and fat composition traits, 10 and 12 significant QTL locations (P<0.05), respectively, were detected on a genome-wide basis, in combined-sire or within-sire analyses. Seven QTL significant for organ weights were found at the proximal end of chromosome 2. This chromosome carries a variant myostatin allele (F94L), segregating from the Limousin ancestry, and this is a positional candidate for the QTL. Ten significant QTL for fat composition were found on chromosomes 19 and 26. Fatty acid synthase and stearoyl-CoA desaturase (SCD1), respectively, are positional candidate genes for these QTL. Two FA QTL found to be common to sire groups in both populations were for percentages of C14:0 and C14:1 (relative to all FAs) on chromosome 26, near the SCD1 candidate gene., (© 2010 AgResearch Ltd, Animal Genetics © 2010 Stichting International Foundation for Animal Genetics.)

A quantitative trait locus (QTL) study was carried out in two countries, recording live animal and carcass composition traits. Back-cross calves (385 heifers and 398 steers) were generated, with Jersey and Limousin breed backgrounds. The New Zealand cattle were reared on pasture to carcass weights averaging 229 kg, whilst the Australian cattle were reared on grass and finished on grain (for at least 180 days) to carcass weights averaging 335 kg. From 11 live animal traits and 31 carcass composition traits respectively, 5 and 22 QTL were detected in combined-sire analyses, which were significant (P < 0.05) on a genome-wise basis. Fourteen significant traits for carcass composition QTL were on chromosome 2 and these were traits associated with muscling and fatness. This chromosome carried a variant myostatin allele (F94L), segregating from the Limousin ancestry. Despite very different cattle management systems between the two countries, the two populations had a large number of QTL in common. Of the 18 traits which were common to both countries, and which had significant QTL at the genome-wise level, eight were significant in both countries.