A Comparison of the Productivity of Suckler Cows of Different Breed Composition

End of project reportThe findings obtained in a comparison of 5 suckler dam breed types {Limousin x Friesian (LF), Limousin x (Limousin x Friesian) (LLF), Limousin (L), Charolais (C) and Simmental x (Limousin x Friesian) (SLF)} and their progeny through to slaughte

Spectrophotometric Libraries, Revised Photonic Passbands and Zero-points for UBVRI, Hipparcos and Tycho Photometry

We have calculated improved photonic passbands for the UBV RI, Hipparcos and Tycho Hp,BT,VT standard systems using the extensive spectrophotometric libraries of NGSL and MILES. Using the Hp passband, we adjusted the absolute flux levels of stars in the spectrophotometric libraries so their synthetic Hp magnitudes matched the precise Hipparcos catalog value. Synthetic photometry based on the renormalized fluxes were compared to the standard UBVRI and BT, VT magnitudes and revised synthetic zero-points were determined. The Hipparcos and Tycho photometry system zero-points were also compared to the V magnitude zero-points of the SAAO UBVRI system, the homogenized UBV system and the Walraven V B system. The confusion in the literature concerning broadband magnitudes, fluxes, passbands and the choice of appropriate mean wavelengths is detailed and discussed in an appendix.Comment: 44 pages, including 16 figures and a 12 page appendi

First detection of a low-mass stellar halo around the young open cluster Eta Chamaeleontis

We have identified several lithium-rich low-mass (0.08<M<0.3 Msun) stars within 5.5 deg of the young open cluster Eta Chamaeleontis, nearly four times the radius of previous search efforts. Of these stars we propose 4 new probable cluster members, and 3 possible members requiring further investigation. These findings are consistent with a dynamical origin for the current configuration of the cluster, without the need to invoke an abnormal Initial Mass Function deficient in low-mass objects. Candidates were selected on the basis of DENIS and 2MASS photometry, NOMAD astrometry and extensive follow-up spectroscopy.Comment: 5 Pages. 5 Figures and 1 Table. Accepted for publication in MNRAS Letters. Higher resolution figures available at http://www.mso.anu.edu.au/~murphysj/

Use of counterfactual population projections for assessing the demographic determinants of population ageing

Counterfactual population projections have been used to estimate the contributions of fertility and mortality to population ageing, a method recently designated as the gold standard for this purpose. We analyse projections with base years between 1850 and 1950 for 11 European countries with long-run demographic data series to estimate the robustness of this approach. We link this approach with stable population theory to derive quantitative indicators of the role of fertility and mortality; consider ways of incorporating net migration; and examine the effect of using alternative indicators of population ageing. A number of substantive and technical weaknesses in the counterfactual projection approach are identified: (1) the conclusions are very sensitive to the choice of base year. Specifically, the level of base year fertility has a major influence on whether fertility or mortality is considered the main driver of population ageing. (2) The method is not transitive: results for two adjacent intervals are unrelated to results for the combined period. Therefore, overall results cannot be usefully allocated between different sub-intervals. (3) Different ageing indices tend to produce similar qualitative conclusions, but quantitative results may differ markedly. (4) Comparisons of alternative models should be with a fixed fertility and mortality projection model rather than with the baseline values as usually done. (5) The standard counterfactual projections approach concatenates the effects of initial age structure and subsequent fertility and mortality rates: methods to separate these components are derived

Cow serum and colostrum immunoglobulin (IgG1) concentration of five suckler cow breed types and subsequent immune status of their calves

peer-reviewedB. Murphy would like to gratefully acknowledge receipt of a Walsh Fellowship provided by Teagasc.The objective of this study was to determine the effect of cow breed type on (a) cow serum and colostrum immunoglobulin (IgG1) concentrations and (b) subsequent calf serum IgG1 concentration and zinc sulphate turbidity (ZST) units. Five cow breed types were examined: LF (Limousin × Friesian), LLF (Limousin × (Limousin × Friesian)), L (Limousin), C (Charolais) and SLF (Simmental × (Limousin × Friesian)). Three blood samples were taken by jugular venipuncture from the cows at approximately 90, 60 and 30 days pre partum, at parturition and at 15 days or more post partum and from the calves at 48 (40 to 56) h post partum. Prior to suckling a 20 ml sample of colostrum was obtained. Milk yield was estimated using the weigh-suckleweigh technique. The decrease in serum IgG1 concentration in cows between 90 days pre partum and parturition was greater (P < 0.01) for LF cows than all other breed types, except SLF. There was no difference between LLF, L, C and SLF cows. There was no effect of cow breed type on colostrum IgG1 concentration. Milk yield was higher (P < 0.001) for LF cows than all other breed types, while that of SLF was higher than the three remaining breed types, which were similar. Calf serum IgG1 concentration and ZST units were higher (P < 0.01) for the progeny of LF cows than all others except SLF. There was no difference between the progeny of LLF, L, C and SLF cows. Calf serum IgG1 was affected by cow breed type and showed a positive relationship with cow serum IgG1 decreases in late pregnancy

Performance and feed intake of five beef suckler cow genotypes and pre-weaning growth of their progeny

peer-reviewedThe effect of beef suckler cow genotype on feed intake, performance, milk yield and on pre-weaning growth of their progeny was determined over four lactations. The five cow genotypes examined were Limousin (L), Charolais (C), Limousin × Holstein-Friesian (LF), Limousin × (Limousin × Holstein-Friesian) (LLF) and Simmental × (Limousin × Holstein-Friesian) (SLF). The herd calved in spring and the progeny spent from April until weaning (October/ November) at pasture with their dams. Live weight (kg) at the start of the indoor winter period was greater (P 0.05) between the genotypes but followed a similar trend to grass silage intake. The decrease in live weight over the indoor winter period was greater (P < 0.01) for L and C cows than for LLF and SLF, whereas LF were intermediate. The increase in live weight during the grazing season was greater (P < 0.01) for C cows than all except L, which were intermediate. Calving difficulty score was greater (P < 0.01) for C cows than LLF, L and SLF, whereas LF were intermediate. Birth weight of calves from LF cows was lower (P < 0.001) than C with L being intermediate, but greater than LLF, with SLF being intermediate. Milk yield (kg/day) was higher (P < 0.001) for LF (9.7) and SLF (8.7) cows than the other genotypes (5.5 to 7.0), which did not differ significantly. Pre-weaning live-weight gain was greater (P < 0.001) for progeny of LF cows than all other genotypes except SLF, which in turn were greater than L and C, with LLF being intermediate. In conclusion, calf pre-weaning growth was higher for cow genotypes with higher milk yield, which was also associated with higher cow DM intake.B. Murphy was in receipt of a Walsh Fellowship provided by Teagasc