2026-10-14T06:14:48Z https://api.figshare.com/v2/oai

oai:figshare.com:article/32634042 2026-10-01T16:58:45Z portal_1172 item_type_8 month_year_10_2026

Can nitrogen use efficiency strategies enhance the sustainability and production efficiency of temperate grazing dairy systems? Aine Murray (24166074) PUREID: 430501885 Nitrogen white clover grazing perennial ryegrass dairy The aim of this thesis was to investigate offsetting conventional nitrogen (N) inputs with more sustainable options in order to maintain or increase production. This was examined through four separate investigations, namely, 1) a retrospective analysis of the incorporation of the legume white clover (Trifolium repens L.; WC) into PRG swards within a high N input grazing dairy system (Chapter 4), 2) a systems experiment investigating PRG-only and PRG-WC swards at two levels of N fertiliser (150 and 250 kg N/ha; Chapter 5), 3) supplementing PRG diets with a rumen protected protein source compared to a rumen degradable protein source within a low CP concentrate supplement (Chapter 6) and 4) comparing herbage production of different N fertiliser types and rates (Chapter 7). Chapter 4 interrogated an existing database, comprised of results from a larger, overall systems experiment, that showed fluctuations in WC content in PRG swards within a high N input (250 kg N/ha, annually) grazing dairy system. In Chapter 5, a separate grazing experiment was established that compared both herbage and milk production of PRG-only and PRG-WC swards at 150 and 250 kg N/ha. Chapter 6 investigated the impact of supplementation of differing protein sources at low amounts on milk production and N use efficiency. Finally, Chapter 7 investigated N fertiliser type and rate on PRG herbage production in a rotational temperate grazing system through a comparison of calcium ammonium nitrate (CAN), urea + N-(n-butyl) thiophosphoric triamide (urea + NBPT) and urea at 150 and 250 kg N/ha per year. In summary, this thesis explored varying options within intensively grazed temperate dairy systems to offset and protect the N inputs while maintaining or perhaps increasing milk production. 2026-10-01T16:58:45Z Text Thesis 10.17034/32634042.v1 https://figshare.com/articles/thesis/Can_nitrogen_use_efficiency_strategies_enhance_the_sustainability_and_production_efficiency_of_temperate_grazing_dairy_systems_/32634042 All Rights Reserved