Abstract The impact of age at first calving (2 versus 3 yrs) and type of forage species grazed in late fall/early winter on lifetime greenhouse gas (GHG) emissions from a cow-calf herd over an 8 or 9 yr period was examined. Farm simulations, based in Manitoba, Canada, were assessed using the Holos model to determine whole-farm GHG emissions for each scenario. The baseline herd consisted of 170 cows, 6 bulls, and their progeny which were sold at weaning, apart from herd replacements. Each simulation began with 207 newborn, female calves, with GHG emissions measured annually. From October to December, 1 of 4 stockpiled forages/forage mixtures were grazed: i) standing corn (COR), ii) tall fescue/meadow bromegrass (TFM), iii) orchardgrass/alfalfa (OGA), and iv) tall fescue/alfalfa/cicer milkvetch (TAC). All other feeding phase diets did not differ across all scenarios. Herd GHG emissions (Mg CO2e) were lower with heifers calving at 2 yrs (3,938 ± 71 Mg CO2e) versus 3 yrs (4,634 ± 72 Mg CO2e). Enteric methane (CH4) was the largest source of GHG emissions accounting for 66% of the total in both the 2- and 3-yr scenarios. Average enteric CH4 values were 3,820±61, 4,251 ± 68, 4,887±79, and 4,220 ± 68 Mg CO2e for simulations grazing COR, TFM, OGA, and TAC, respectively and were inversely related to total digestible nutrient (TDN) content of the forage mixtures with 72, 54, 45 and 55% TDN. Emissions were highest from OGA, the lowest quality forage, in both calving scenarios. Nitrous oxide emissions from livestock manure...
AI-powered Research feed
Round-ups are the summaries of handpicked papers around trending topics published every week. These would enable you to scan through a collection of papers and decide if the paper is relevant to you before actually investing time into reading it.
Climate change Research Articles published between Jun 20, 2022 to Jun 26, 2022
Jun 27, 2022
Articles Included: 2
One eighth of the bird species in the world is considered globally threatened; the avifauna of Iraq comprises 409 species and is considered as the maj...Read More