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

Huisman, Abe; Brown, D. J.; Ball, Alex; Graser, H. U.

doi:10.1071/ea08119

Cited by 50 publications

(26 citation statements)

References 17 publications

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“…In general, the heritability estimates found in the present study agree well with estimates from Australian sheep flocks (Safari et al 2005;Huisman et al 2008), indicating that these traits will respond to selection. The heritability estimates for proportion of fibres below 15 micron and for proportion of fibres above 30 micron were 0.59 and 0.45, respectively.…”

Section: Wool Traitssupporting

confidence: 80%

Identifying indicator traits for breech strike in Merino sheep in a Mediterranean environment

2014

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Abstract. Data from 2833 unmulesed Merino lambs from 49 sires and 1535 dams that were born from 2005 to 2009, were used to identify indicator traits for breech strike in a Mediterranean environment. Sheep were managed in a normal production environment where no preventative treatments were applied to protect them from being struck by flies, but were immediately treated when found to be fly struck. Seventy-seven skin, body conformation, wool, disease and production traits that may contribute to breech strike and that could qualify as potential indicator traits were recorded on progeny at birth, weaning, postweaning, yearling, spring and at pre-and post-hogget age at~18 months of age. In all, 31% of ewes and 22% of rams were fly struck in the breech area between birth and hogget shearing. The heritability of and the phenotypic and genetic correlations between the potential indicator traits and breech strike were estimated. The results showed that breech strike is a heritable trait (h 2 = 0.51 AE 0.10), and that the most important indicator traits for breech strike were dags, scored at any time, especially at hogget age (r g = 0.81 AE 0.15), spring (r g = 0.77 AE 0.13) or at weaning (r g = 0.64 AE 0.00), urine stain scored at weaning (r g = 0.54 AE 0.13) and marking (r g = 0.51 AE 0.15), neck wrinkle at hogget age (r g = 0.46 AE 0.13) and breech cover (r g = 0.32 AE 0.15) scored at post-weaning shearing. These traits could be used to select indirectly for breech strike resistance in a Mediterranean environment.

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Section: Wool Traitssupporting

confidence: 80%

Identifying indicator traits for breech strike in Merino sheep in a Mediterranean environment

2014

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“…There were high heritability estimates for the major wool production and wool quality traits whereas other wool quality, wool color, and visual traits were more moderately heritable, which is consistent with the review of Safari et al (2005) and more recent reports from several large Merino data sets (Asadi Fozi et al, 2005;Safari et al, 2007;Huisman et al, 2008;Swan et al, 2008Brown et al, 2010Brown et al, , 2013.…”

Section: Heritabilitysupporting

confidence: 74%

“…However, effective breeding programs require information on the genetic relationships between these selection traits and the meat traits measured in the carcass as well as with wool traits. Although several consistent estimates of the genetic variation exist for the major wool and meat production traits (Safari et al, 2005(Safari et al, , 2007Greeff et al, 2008;Huisman et al, 2008;, there are few estimates of genetic correlations between wool and meat traits, particularly for Merino sheep. This second paper of a series reports estimates of genetic and phenotypic correlations between several wool production and quality traits and carcass meat traits, including lean meat yield and the weight of various cuts, from Merino sheep in the Information Nucleus (IN; Fogarty et al, 2007;van der Werf et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Genetic correlations between wool traits and carcass traits in Merino sheep

Mortimer¹,

Hatcher²,

Fogarty³

et al. 2017

Journal of Animal Science

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ABSTRACT:Genetic correlations between 29 wool production and quality traits and 14 whole carcass measures and carcass component traits were estimated from the Information Nucleus of 8 flocks managed across a range of Australian sheep production environments and genetically linked. Wool data were from over 5,000 Merino progeny born over 5 yr, whereas carcass data were from over 1,200 wether progeny of over 176 sires, slaughtered at about 21 kg carcass weight, on average. Wool traits included yearling and adult records for wool weight, fiber diameter, fiber diameter variation, staple strength, scoured color, and visual scores for breech and body wrinkle. Whole carcass measures included HCW, dressing percentage (DP), and various measures of fat depth and eye muscle dimensions. Carcass components were obtained by dissection, and lean meat yield (LMY) was predicted. Heritability estimates for whole carcass measures ranged from 0.12 ± 0.08 to 0.35 ± 0.10 and ranged from 0.17 ± 0.10 to 0.46 ± 0.10 for carcass dissection traits, with no evidence of important genotype × environment interactions. Genetic correlations indicated that selection for increased clean wool weight will result in reduced carcass fat (−0.17 to −0.34) and DP (−0.48 ± 0.15), with little effect on carcass muscle. Selection for lower fiber diameter will reduce HCW (−0.48 ± 0.15) as well as carcass fat (0.14 to 0.27) and muscle (0.21 to 0.50). There were high genetic correlations between live animal measures of fat and muscle depth and the carcass traits (generally greater than 0.5 in size). Selection to increase HCW (and DP) will result in sheep with fewer wrinkles on the body (−0.57 ± 0.10) and barer breeches (−0.74 ± 0.12, favorable), with minor deterioration in scoured wool color (reduced brightness and increased yellowness). Selection for reduced fat will also result in sheep with fewer body wrinkles (−0.42 to −0.79). Increasing LMY in Merinos through selection would result in a large reduction in carcass fat and DP (−0.66 to −0.84), with a smaller increase in carcass muscle and some increase in wool weight and wrinkles. Although no major antagonisms are apparent between the wool and carcass traits, developing selection indexes for dualpurpose wool and meat breeding objectives will require accurate estimates of genetic parameters to ensure that unfavorable relationships are suitably considered. The findings will aid development of dual-purpose wool and meat breeding objectives.

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“…Kelly et al (1996) showed that in comparison to progeny from single-bearing ewes fed to maintain maternal liveweight during pregnancy, genetically identical progeny from ewes fed to lose 10 kg between Days 50 and 140 of pregnancy produced~0.14 kg less clean wool that was alsõ 0.1-mm broader at their hogget shearing. These differences in clean fleece weight and fibre diameter between single-born progeny were permanent (Kelly et al 2006), and this is consistent with the differences in wool production and quality that persist between single-and twin-born lambs until at least 2-3 years of age (Huisman et al 2008).…”

Section: Introductionsupporting

confidence: 59%

“…By contrast, while birth-type effects on fibre diameter of wool produced by progeny generally persisting to maturity rear-type effects were only evident at hogget age. Few studies have reported the effects of birth type or rear type on clean fleece weight and fibre diameter beyond 2-3 years (Huisman et al 2008).…”

Section: Discussionmentioning

confidence: 99%

Improving the nutrition of Merino ewes during pregnancy increases the fleece weight and reduces the fibre diameter of their progeny's wool during their lifetime and these effects can be predicted from the ewe's liveweight profile

Thompson

Ferguson

Gordon³

et al. 2011

Anim. Prod. Sci.

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Abstract. Nutrition of ewes during pregnancy can have permanent impacts on the production potential of their progeny. The hypothesis tested in the experiments reported in this paper was that improving the nutrition of Merino ewes during pregnancy and lactation increases the fleece weight and reduces the fibre diameter of their progeny's wool during their lifetime. In addition, that these effects on the progeny's wool production can be predicted from the ewe's liveweight profile. At sites in Victoria and Western Australia in each of 2 years, a wide range in the liveweight and condition score profiles of Merino ewes was generated by varying the amount of supplements fed from joining to Day 100 of pregnancy and the amount of feed on offer grazed from Day 100 to weaning. The site in Victoria was based on perennial pastures and included both single-and twin-bearing ewes whereas the site in Western Australia was based on annual pastures and included singlebearing ewes only. The production and characteristics of wool from the progeny were measured until 51 months of age at the site in Victoria and 33 months of age at the site in Western Australia. The nutritional treatments and the resulting changes in ewe liveweight had significant impacts on the fleece weight and to a lesser extent the fibre diameter of wool produced by their progeny, but there were no consistent effects on other characteristics of progeny fleece wool. The fleece weight of the progeny was related to the liveweight change during pregnancy of their mothers (P < 0.05) and the relationships were similar for the two experiments at each site. At the site in Victoria, a loss of 10 kg in ewe liveweight between joining and Day 100 of pregnancy reduced fleece weight by~0.2 kg at each shearing until 51 months of age whereas gaining 10 kg from Day 100 of pregnancy to lambing had the opposite effect. The effect of changes in ewe liveweight during late pregnancy on the fleece weight of their progeny at each shearing was of similar magnitude at the site in Western Australia. When evident, the effect of the ewe liveweight profile on the fibre diameter of progeny wool was opposite to the effect on clean fleece weight and the effect of poor nutrition in early to mid pregnancy could be completely overcome by improving nutrition during late pregnancy. Twin-born and reared progeny produced~0.3 kg less clean wool at each shearing (P < 0.001) that was 0.3-mm broader (P < 0.001) than that from single-born progeny at the site in Victoria. However, the effects of varying ewe nutrition and ewe liveweight change during pregnancy on fleece weight and fibre diameter of progeny wool were similar (P > 0.05) for both single-and twin-born or reared progeny. Overall, these results supported our hypothesis and it is clear that the nutritional management of Merino ewes during pregnancy is important for optimal wool production from their progeny during their lifetime.

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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

Cited by 50 publications

References 17 publications

Identifying indicator traits for breech strike in Merino sheep in a Mediterranean environment

Identifying indicator traits for breech strike in Merino sheep in a Mediterranean environment

Genetic correlations between wool traits and carcass traits in Merino sheep

Improving the nutrition of Merino ewes during pregnancy increases the fleece weight and reduces the fibre diameter of their progeny's wool during their lifetime and these effects can be predicted from the ewe's liveweight profile

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