Grassland Sciencehttp://hdl.handle.net/11019/122024-03-29T00:25:31Z2024-03-29T00:25:31ZGenetic gain in perennial ryegrass (Lolium perenne) varieties 1973 to 2013McDonagh, J.O’Donovan, M.McEvoy, M.Gilliland, T. J.http://hdl.handle.net/11019/36442024-03-03T04:23:28Z2016-08-10T00:00:00ZGenetic gain in perennial ryegrass (Lolium perenne) varieties 1973 to 2013
McDonagh, J.; O’Donovan, M.; McEvoy, M.; Gilliland, T. J.
Perennial ryegrass (Lolium perenne) forms the basis of grassland production in temperate pastures and is globally one of the most important forage grasses. Consequently, there has been large plant breeding industry investment over the past 40 years in producing new varieties and independent testing systems designed to identify and list those with the most improved performances. This study was conducted at the Plant Testing Station, Crossnacreevy, Northern Ireland and compared the DM yield and sward density of new varieties submitted from 1973 to 2013 and grass digestibility from 1980 to 2013, under conservation and simulated grazing managements. A variety × years matrix was compiled for each parameter and comparable means between varieties never in side by side performance trials were produced. Dry matter yields showed an overall significant (p < 0.001) average annual increase of 0.52 % under conservation and 0.35 % under simulated grazing, with similar gain levels within maturity groups or ploidies. These rates were not constant over time, and periods of no gain occurred in various variety groupings. Sward density of the examined varieties did not change significantly. Herbage digestibility showed no improvement over the timeframe but had the largest differences between concurrent varieties, indicating that improvements were possible in the future. The study indicated that plant breeding gains were primarily DM yield focused with sward density remaining stagnant over the 40 years, while the lack of grass digestibility improvement appeared to only require more time to overcome. Evidence of benefits and risks of variety testing influences on plant breeding objectives was discussed.
peer-reviewed
2016-08-10T00:00:00ZImproved representation of cattle herd dynamics for bio-physical modelling of pathways to a climate neutral land sectorHenn, DanielHumphreys, JamesDuffy, ColmGibbons, JamesStyles, Davidhttp://hdl.handle.net/11019/36302024-03-03T04:19:13Z2023-12-01T00:00:00ZImproved representation of cattle herd dynamics for bio-physical modelling of pathways to a climate neutral land sector
Henn, Daniel; Humphreys, James; Duffy, Colm; Gibbons, James; Styles, David
Livestock production contributes to food security and livelihood improvement globally but places a significant burden on the environment. In Ireland, an ongoing transition towards highly profitable dairy production after the phasing out of EU milk quotas has changed the composition of the national cattle herd with more dairy and fewer beef cows. This shift impacts greenhouse gas (GHG) accounting across different cattle cohorts, e.g. increasing the proportion of calves from the dairy herd. Dairy x beef crossbreeds (DxB) increasingly contribute to national beef output, leveraging larger average daily liveweight gain (ADG) traits from beef breeding bulls.
OBJECTIVE
Prospective modelling of climate and land consequences arising from alternative cattle production strategies requires more accurate simulation of cohort-specific ADG and associated feed requirements and GHG emissions.
METHODS
A new COHORTS model was developed to improve national climate scenario mitigation modelling. COHORTS is capable of simulating 21 genetics-gender-age cohorts calibrated to Irish performance, using just a few basic input parameters (at minimum dairy- and beef-cow numbers). A cohort specific ADG and average standing liveweight is estimated for each genetic (pure dairy calves, DxB and pure beef calves), gender and age combination, enabling more accurate calculation of energy requirements and enteric fermentation emissions based on IPCC Tier 2 calculations.
RESULTS AND CONCLUSIONS
National simulation of cattle numbers, enteric fermentation emissions and beef outputs were validated against relevant Irish inventories. For the period between 2006 and 2020, simulations resulted in total cattle numbers, emissions and beef production within 4%, 1.8% and 0.5%, respectively, of officially reported data. Our results indicate that climate projections based on average emission factors for pre-adult cattle cohorts may overestimate emissions in scenarios with projected growing dairy calf numbers and declining beef calf numbers.
SIGNIFICANCE
Validation using a 15-year data time series provides a high degree of confidence that COHORTS can be used to represent future herd dynamics in a wide range of scenarios, supporting robust policy regarding GHG mitigation, livestock production and land use – distinguishing between different levels of dairy or beef specialisation and across different levels of performance to predict forage (land) requirements and GHG emissions more accurately. COHORTS can be easily adapted for other countries, even when limited data are available.
peer-reviewed
2023-12-01T00:00:00ZA comparison of farm labour, profitability, and carbon footprint of different management strategies in Northern European grassland sheep systemsMorgan-Davies, C.Kyle, J.Boman, I.A.Wishart, H.McLaren, A.Fair, S.Creighton, P.http://hdl.handle.net/11019/35592024-03-03T04:25:10Z2021-06-01T00:00:00ZA comparison of farm labour, profitability, and carbon footprint of different management strategies in Northern European grassland sheep systems
Morgan-Davies, C.; Kyle, J.; Boman, I.A.; Wishart, H.; McLaren, A.; Fair, S.; Creighton, P.
CONTEXT
Sheep production systems need to become more carbon efficient to meet growing public demands on climate change. Some of the ways postulated to achieve this is to implement new technologies and management strategies such as precision livestock farming (PLF), increased use of high genetic merit animals with estimated breeding values through artificial insemination (AI) where practical, and the use of prolific breeds. However, the carbon footprint impact of these strategies has not to-date been quantified. Additionally, international experience indicates that uptake of such strategies is low due, in part, to the perception of increased workload especially during busy periods of the sheep year.
OBJECTIVES
This trans-European study investigates the impact of differing sheep management strategies on farm labour input, carbon footprint as well as the on-farm profitability, to address these concerns.
METHODS
Four management strategies were considered i) use of technology (PLF), ii) use of performance recording for higher genetic merit, iii) use of AI for higher genetic merit and iv) and use of prolific breeds, in 14 case study flocks located in areas typical of Northern European grassland sheep production systems across Scotland, France, Ireland and Norway. For each management strategy, paired case study flocks were identified. Labour was assessed at key handling events using video recording, farmers' diaries, and questionnaires, which were later quantified and classed into key tasks to create normalised labour profiles for each case study flock. The carbon footprint was quantified using a carbon calculator tool (www.agrecalc.com). Financial net margins were calculated.
RESULTS AND CONCLUSIONS
Results highlighted that introducing PLF technology on extensive farms reduced labour by 20% and increased economic margins by £9/ewe but with a concurrent increase in carbon emissions (kg CO2e/ kg of meat produced). Using performance recording on sheep farms for achieving higher genetic merit increased economic margins by £6/ewe, and reduced carbon emissions (kg CO2e) per kg of meat produced but resulted in 10% extra labour. AI on farms increased economic margins by £50/ewe, did not incur extra labour and increased carbon efficiency in terms of kg CO2e/kg meat produced. Finally, high prolific breeds did not significantly increase labour input at key handling events and resulted by higher economic margins (+£3/ewe), without a change in terms of kg CO2e/kg meat produced.
SIGNIFICANCE
These novel case studies clearly illustrate it is possible to increase carbon and labour efficiency by adopting technology, changing breeding management or ewe breed on sheep farms.
peer-reviewed
2021-06-01T00:00:00ZEffects of grass and maize silage feed value, offering soybean meal with maize silage, and concentrate feed level in late pregnancy, on ewe and lamb performanceKeady, T.W.J.Hanrahan, J.P.http://hdl.handle.net/11019/35402024-03-03T04:22:54Z2021-01-01T00:00:00ZEffects of grass and maize silage feed value, offering soybean meal with maize silage, and concentrate feed level in late pregnancy, on ewe and lamb performance
Keady, T.W.J.; Hanrahan, J.P.
In many countries, daily herbage accumulation on pasture declines towards zero during the winter period; thus, many pregnant ewes are housed and offered conserved forages supplemented with concentrate prior to parturition. The effects of forage type and feed value (FV), offering soybean meal with maize silage during mid and late pregnancy, and concentrate feed level in late pregnancy on the performance of ewes and their progeny (to slaughter) were evaluated. Ewes (n = 151) were assigned to one of nine treatments from mid-pregnancy until lambing. Medium FV and high FV grass silages (metabolisable energy concentrations of 10.7 and 12.0 MJ/kg DM) were offered ad libitum supplemented with either 15 or 25 kg concentrate/ewe during late pregnancy. Low and high DM maize silages (starch concentrations of 80 and 315 g/kg DM) were offered ad libitum either alone or with soybean meal (200 g/d) and supplemented with 15 kg concentrate during late pregnancy. A final treatment consisted of high FV grass silage supplemented with 5 kg soybean/ewe over the final 4 weeks of pregnancy. Ewes and lambs were put to pasture in a rotational-grazing system within 3 days of lambing. There were no interactions (P > 0.05) between grass silage FV and concentrate feed level for ewe or lamb traits. Increasing grass silage FV increased food intake (P < 0.001) during late pregnancy, ewe BW and body condition score (BCS) at lambing (P < 0.001), lamb BW at birth (P < 0.001) and weaning (P < 0.05), and reduced age at slaughter (P = 0.06). Increasing concentrate feed level increased metabolisable energy (P < 0.05) intake during late pregnancy but had no effect (P > 0.05) on ewe or lamb performance. Increasing maize DM at harvest and offering soybean meal with maize silage increased food intake (P < 0.001) and ewe BW and BCS at lambing (P < 0.05 or P < 0.01). Offering soybean meal with maize silage increased lamb BW at birth (P < 0.01) and reduced age at slaughter (P < 0.05). Reducing supplementation of high FV grass silage to 5 kg of soybean meal had no effect (P > 0.05) on animal performance. Replacing grass silage with maize silage did not affect (P > 0.05) BW gain of lambs. It is concluded that increasing the FV of the grass silage offered during pregnancy had the greatest positive impact on ewe and lamb performance.
peer-reviewed
2021-01-01T00:00:00Z