Frank P. O'Mara
University College Dublin
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Publication
Featured researches published by Frank P. O'Mara.
Philosophical Transactions of the Royal Society B | 2008
Pete Smith; Daniel Martino; Zucong Cai; Daniel Gwary; H. Henry Janzen; Pushpam Kumar; Bruce A. McCarl; Stephen M. Ogle; Frank P. O'Mara; Charles W. Rice; Bob Scholes; Oleg Sirotenko; Mark Howden; Tim A. McAllister; Genxing Pan; Vladimir Romanenkov; Uwe A. Schneider; Sirintornthep Towprayoon; Martin Wattenbach; Jo Smith
Agricultural lands occupy 37% of the earths land surface. Agriculture accounts for 52 and 84% of global anthropogenic methane and nitrous oxide emissions. Agricultural soils may also act as a sink or source for CO2, but the net flux is small. Many agricultural practices can potentially mitigate greenhouse gas (GHG) emissions, the most prominent of which are improved cropland and grazing land management and restoration of degraded lands and cultivated organic soils. Lower, but still significant mitigation potential is provided by water and rice management, set-aside, land use change and agroforestry, livestock management and manure management. The global technical mitigation potential from agriculture (excluding fossil fuel offsets from biomass) by 2030, considering all gases, is estimated to be approximately 5500–6000 Mt CO2-eq. yr−1, with economic potentials of approximately 1500–1600, 2500–2700 and 4000–4300 Mt CO2-eq. yr−1 at carbon prices of up to 20, up to 50 and up to 100 US
Animal | 2008
Joe Patton; J.J. Murphy; Frank P. O'Mara; S.T. Butler
t CO2-eq.−1, respectively. In addition, GHG emissions could be reduced by substitution of fossil fuels for energy production by agricultural feedstocks (e.g. crop residues, dung and dedicated energy crops). The economic mitigation potential of biomass energy from agriculture is estimated to be 640, 2240 and 16 000 Mt CO2-eq. yr−1 at 0–20, 0–50 and 0–100 US
Animal | 2009
Joe Patton; J.J. Murphy; Frank P. O'Mara; S.T. Butler
t CO2-eq.−1, respectively.
Agriculture, Ecosystems & Environment | 2007
Pete Smith; Daniel Martino; Zucong Cai; Daniel Gwary; H. Henry Janzen; Pushpam Kumar; Bruce A. McCarl; Stephen M. Ogle; Frank P. O'Mara; Charles W. Rice; Bob Scholes; Oleg Sirotenko; Mark Howden; Tim A. McAllister; Genxing Pan; Vladimir Romanenkov; Uwe A. Schneider; Sirintornthep Towprayoon
The milk production, energy balance (EB), endocrine and metabolite profiles of 10 New Zealand Holstein Friesian (NZ) cows and 10 North American Holstein Friesian (NA) cows were compared. The NA cows had greater peak milk yields and total lactation milk yields (7387 v. 6208 kg; s.e.d. = 359), lower milk fat and similar protein concentrations compared with the NZ cows. Body weight (BW) was greater for NA cows compared with NZ cows throughout lactation (596 v. 544 kg; s.e.d. = 15.5), while body condition score (BCS) tended to be lower. The NA strain tended to have greater dry matter intake (DMI) (17.2 v. 15.7 kg/day; s.e.d. = 0.78) for week 1 to 20 of lactation, though DMI as a proportion of metabolic BW was similar for both strains. No differences were observed between the strains in the timing and magnitude of the EB nadir, interval to neutral EB, or mean daily EB for week 1 to 20 of lactation. Plasma concentrations of glucose and insulin were greater for NA cows during the transition period (day 14 pre partum to day 28 post partum). Plasma IGF-I concentrations were similar for the strains at this time, but NZ cows had greater plasma IGF-I concentration from day 29 to day 100 of lactation, despite similar calculated EB. In conclusion, the results of this study do not support the premise that the NZ strain has a more favourable metabolic status during the transition period. The results, however, indicate that NZ cows begin to partition nutrients towards body reserves during mid-lactation, whereas NA cows continue to partition nutrients to milk production.
Grass and Forage Science | 2005
E. Kennedy; M. O'Donovan; J.P. Murphy; Luc Delaby; Frank P. O'Mara
This study investigated the physiological basis of differences in nutrient partitioning between the North American (NA) and New Zealand (NZ) strains of Holstein-Friesian cattle by determining the responses to homeostatic challenges at two stages of lactation. Glucose tolerance tests, epinephrine challenges and insulin challenges were carried out on consecutive days commencing on day 32 ± 0.48 (mean ± s.e.) of lactation (T1) and again commencing on day 137 ± 2.44 of lactation (T2). The insulin and non-esterified fatty acid (NEFA) responses to glucose infusion did not differ between the strains. The NZ strain had a greater clearance rate (CR) of glucose (2.04% v. 1.66%/min) and tended to have a shorter (34.4 v. 41.1 min) glucose half-life (t½) at T2 when infused with glucose. The NA cows had a greater glucose response to epinephrine infusion across T1 and T2, and tended to have a greater insulin response to epinephrine infusion. Plasma NEFA concentration declined to similar nadir concentrations for both strains at T1 in response to insulin, though from a higher basal concentration in NA cows, resulting in a greater (-2.29 v. -1.38) NEFA area under the response curve for NA cows. Glucose response to insulin varied with time, tending to be greater for NA at T1, but tending to be lower for NA at T2. The results indicated that NA cows had a greater glycogenolytic response to epinephrine, but both strains had similar lipolytic responses. The results also imply that higher basal circulating NEFA concentrations in the NA strain in early lactation were not due to diminished adipose tissue responsiveness to insulin. There were indications that glucose CR was greater in NZ cows in mid-lactation, and may form the basis of increased body tissue accretion during mid- to late-lactation in this strain.
Grass and Forage Science | 2004
D. K. Lovett; A. Bortolozzo; P. Conaghan; P. O'Kiely; Frank P. O'Mara
Irish Journal of Agricultural and Food Research | 2005
J. Caplis; Michael G. Keane; Aidan P Moloney; Frank P. O'Mara
Grass and Forage Science | 2006
E. Kennedy; M. O'Donovan; J.P. Murphy; Frank P. O'Mara; Luc Delaby
Grass and Forage Science | 2006
Lovett Dk; D. McGilloway; A. Bortolozzo; M. Hawkins; J.J. Callan; B. Flynn; Frank P. O'Mara
Livestock Science | 2008
S. McNamara; J.J. Murphy; Frank P. O'Mara; M. Rath; John F. Mee