44,220 research outputs found
Post-weaning weight is highly genetically correlated to adult ewe weights
No full textS. F. Walkom, F. D. Brien, M.L. Hebart, N. M. Fogarty, S. Hatcher and W. S. Pitchfor
Season and reproductive status rather than genetics factors influence change in ewe weight and fat over time. 3. Analysis of Merino ewes
No full textPublished: 22 April 2014The 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 accounted for 92% of the genetic variation in weight of Merino ewes bred across five production cycles. A genetic correlation of 0.85 suggested that ewes that were superior at maintaining their condition when rearing a single lamb would maintain this superiority when rearing multiple lambs. To improve weight and condition of Merino ewes during the ‘tough’ times, when nutrient requirements are not met by the pasture, selection can be made at any time and this will result in increased genetic condition at all times.S. F. Walkom, F. D. Brien, M. L. Hebart, N. M. Fogarty, S. Hatcher and W. S. Pitchfor
Evidence for the decay B0→J/ψω and measurement of the relative branching fractions of meson decays to J/ψη and J/ψη′
No full textFirst evidence of the B 0 → J / ψ ω decay is found and the B s 0 → J / ψ η and B s 0 → J / ψ η ′ decays are studied using a dataset corresponding to an integrated luminosity of 1.0 fb -1 collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV. The branching fractions of these decays are measured relative to that of the B 0 → J / ψ ρ 0 decay:frac(B (B 0 → J / ψ ω), B (B 0 → J / ψ ρ 0)) = 0.89 ± 0.19 (stat) - 0.13 + 0.07 (syst),frac(B (B s 0 → J / ψ η), B (B 0 → J / ψ ρ 0)) = 14.0 ± 1.2 (stat) - 1.5 + 1.1 (syst) - 1.0 + 1.1 (frac(f d, f s)),frac(B (B s 0 → J / ψ η ′), B (B 0 → J / ψ ρ 0)) = 12.7 ± 1.1 (stat) - 1.3 + 0.5 (syst) - 0.9 + 1.0 (frac(f d, f s)), where the last uncertainty is due to the knowledge of f d / f s, the ratio of b-quark hadronization factors that accounts for the different production rate of B 0 and B s 0 mesons. The ratio of the branching fractions of B s 0 → J / ψ η ′ and B s 0 → J / ψ η decays is measured to befrac(B (B s 0 → J / ψ η ′), B (B s 0 → J / ψ η)) = 0.90 ± 0.09 (stat) - 0.02 + 0.06 (syst)
APC/C and SCFcyclin F Constitute a Reciprocal Feedback Circuit Controlling S-Phase Entry
No full textSummaryThe anaphase promoting complex/cyclosome (APC/C) is an ubiquitin ligase and core component of the cell-cycle oscillator. During G1 phase, APC/C binds to its substrate receptor Cdh1 and APC/CCdh1 plays an important role in restricting S-phase entry and maintaining genome integrity. We describe a reciprocal feedback circuit between APC/C and a second ubiquitin ligase, the SCF (Skp1-Cul1-F box). We show that cyclin F, a cell-cycle-regulated substrate receptor (F-box protein) for the SCF, is targeted for degradation by APC/C. Furthermore, we establish that Cdh1 is itself a substrate of SCFcyclin F. Cyclin F loss impairs Cdh1 degradation and delays S-phase entry, and this delay is reversed by simultaneous removal of Cdh1. These data indicate that the coordinated, temporal ordering of cyclin F and Cdh1 degradation, organized in a double-negative feedback loop, represents a fundamental aspect of cell-cycle control. This mutual antagonism could be a feature of other oscillating systems
Season and reproductive status rather than genetic factors influence change in ewe weight and fat over time. 2. Spline analysis of crossbred ewes
No full textPublished: 18 February 2014The success of slaughter lamb enterprises is heavily influenced by the ability of the breeding ewe to produce a lamb annually across variable environments. It has been shown that by maintaining heavier weight and condition across the annual production cycle producers can make significant improvements in maternal performance. This paper follows on from a previous analysis of crossbred ewes within the Maternal Central Progeny Test and examines the potential to select for reduced fluctuation in weight and fat across the production cycle. A cubic spline model was fitted to the weight and fat score data from the first three parities of 2688 first-cross ewes. The analysis partitioned the influence of environment, reproduction and genetic effects on the shape of the weight and fat score splines across three parities. Yearly and seasonal variation in feed supply and the demands of raising a lamb are the major influences on fluctuations in the weight and fat score of the breeding ewe. The genetic effects were constant across time with 98 and 92% of the genetic variation for weight and fat, respectively, associated with the spline’s intercept. In agreement with the findings of the first paper of the series it can be concluded that genetic lines do not re-rank for weight or fat score over time. The influence of sire breed on weight and fat score was constant across time with sire breeds fluctuating in parallel across time. As a result it is concluded that to avoid low fat reserves and the subsequent low fertility during the ‘tough’ periods, selection to improve ewe body condition could be made at any time and under any environmental conditions.S. F. Walkom, F. D. Brien, M. L. Hebart, N. M. Fogarty, S. Hatcher and W. S. Pitchfor
Season and reproductive status rather than genetics factors influence change in ewe weight and fat over time. 1. Analysis of crossbred ewes
No full textPublished: 11 April 2014The Australian sheep industry has historically made rapid advances in the quality and quantity of meat and wool through genetic improvement, but unfortunately, maternal performance, i.e. number of lambs weaned, is well below desired levels. The aim of the present paper is to investigate the potential to select for increased weight and fat across the production cycle to improve maternal performance. The analysis explores the potential to improve the weight and fat score of breeding ewes during ‘tough’ periods (i.e. when nutrient requirements are not met by the pasture), preparing the breeding ewe for the upcoming mating without an increase in overall ewe size. The 2846 ewes within the maternal central progeny test were weighed and scored for fatness 12 times across three production cycles. Low to moderate heritability estimates for weight (0.04–0.23) and fat (0.02–0.06) changes across the production cycle provide little hope for selection against weight loss during tough periods. The analysis showed very strong genetic correlations between time-points across multiple production cycles for both weight (0.99–0.93) and fat score (0.88–0.98). The very strong correlations between measurements suggest that weight and fat score are genetically the same trait throughout the ewe’s adult life. With 74% and 77% of the genetic variation in weight and fat, respectively, constant across the production cycle, there is little opportunity to select against the natural fluctuations in weight and fat reserves. In conclusion, selection for increased fat can be made at any time and it will result in more fat during tough times.S. F. Walkom, F. D. Brien, M. L. Hebart, N. M. Fogarty, S. Hatcher and W. S. Pitchfor
Meat quality in merino ram hoggets
No full textGenetic, environmental and management effects on meat pH and colour and their relationship with other production traits were estimated from pooled data based on carcase measurements from 5870 Merino hogget rams from New South Wales, South Australia and Western Australia. Principal component analyses failed to generate a trait which would be superior to the direct use of meat pH and colour as criteria in selection against dark cutting meat. No genetic or environmental links were found between dark cutting and production traits that could provide a causative effect or potential for indirect selection. In addition to parameter estimates, the contribution of various sources of variation for meat pH and colour have been quantified and the implications of the findings are discussed.S. F. Walkom, F.D. Brien, M.L. Hebart, J.C. Greeff, D.L. Hopkins and W.S. Pitchfor
Partitioning genetic variance in composite sheep
No full textAustralian sheep producers have been moving towards an increased use of composite crossbred ewes to achieve higher performance and greater genetic gain, taking advantage of the high value lamb market. Sheep research has traditionally been carried out on purebred flocks or their first and second crosses with replication and uniformity of breed types within the data. Within composite lines, the breed combinations are often complex, with multiple breeds in variable proportions with few sheep per breed combination. To enable estimation of between and within breed genetic effects, the analysis performed in our study included both additive and dominance genetic effects at the breed level. Breed additive effects contributed to 1.3% of the variation in weight. The variance associated with breed dominance effects were significant for both weight and height (10 and 5%). Results from this analysis on the small sub set are promising, and suggest the model will account for breed effects when a larger composite sheep data set is analysed.S.F. Walkom, A.P. Verbyla, F.D. Brien, M.L. Hebart and W.S. Pitchfordhttp://www.aaabg.org/aaabg19/?conference19=19th+AAABG+Conference+201
Corrigendum to “Presence and function of kisspeptin/KISS1R system in swine ovarian follicles” (Theriogenology (2018) 115 (1–8), (S0093691X1830147X), (10.1016/j.theriogenology.2018.04.006))
No full textThe authors regret the following changes to the author group G. Basinia, F. Grassellia, S. Bussolatia, R. Ciccimarraa, M. Maranesib, A. Bufalarib, C. Dall'Agliob, F. Parilloc,#, M. Zeranib,c,*. a Dipartimento di Scienze Mediche Veterinarie, Università di Parma, 43126 Parma, Italy. b Dipartimento di Medicina Veterinaria, Università di Perugia, 06126 Perugia Italy. c Scuola di Bioscienze e Medicina Veterinaria, Università di Camerino, 62024 Matelica Italy. # Deceased. * Corresponding author: tel.: +39 0755857642; fax +39 0755857654. E-mail address: [email protected] (M. Zerani). And to the acknowledgements and figures
Measurement of the CP-violating phase \phi s in Bs->J/\psi\pi+\pi- decays
No full textMeasurement of the mixing-induced CP-violating phase phi_s in Bs decays is of prime importance in probing new physics. Here 7421 +/- 105 signal events from the dominantly CP-odd final state J/\psi pi+ pi- are selected in 1/fb of pp collision data collected at sqrt{s} = 7 TeV with the LHCb detector. A time-dependent fit to the data yields a value of phi_s=-0.019^{+0.173+0.004}_{-0.174-0.003} rad, consistent with the Standard Model expectation. No evidence of direct CP violation is found
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