The effect of increasing sward species diversity on enteric methane emissions from Holstein-Friesian and Holstein-Friesian × Jersey crossbred dairy cows in a rotational grazing system
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Published Version
Date
2025
Authors
Dwan, Charles
Horan, Brendan
Buckley, Frank
Jezequel, Alann
Costigan, H.
Delaby, Luc
Galvin, Norann
Lahart, Ben
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier Inc.
Published Version
Abstract
An experiment was conducted to investigate the effect of sward system and dairy cow breed on enteric methane emissions from spring-calving grazing dairy cows using GreenFeed technology (C-lock Inc.). The study comprised 3 sward systems: a perennial ryegrass (Lolium perenne L.) monoculture receiving 250 kg N/ha per year (PRG), a perennial ryegrass white clover (Trifolium repens L.) sward receiving 125 kg N/ha per year (PRGWC), and a multispecies sward sown with grasses, legumes and herbs receiving 125 kg N/ha/yr (MSS). Each sward system had its own herd of dairy cows on a total area of 18.7 ha divided into 20 paddocks. Each herd comprised Holstein-Friesian (HF) purebred and HF × Jersey crossbred (JFX) animals which were divided equally across each sward system. Milk production and methane emissions were measured from mid-May to mid-October, and DMI and rumen characteristics were measured in late-July and early-October (165 and 228 DIM, respectively). Milk solids (milk fat + protein; MSo) was greatest for cows grazing MSS due to an associated increase in DMI. The greatest average daily methane output across the study was observed for cows grazing PRGWC (311 g/d) while those grazing PRG and MSS were similar (294 and 297 g/d, respectively). Methane intensity (g methane/kg MSo) was reduced for the MSS cows compared with both the PRG and PRGWC cows (208, 217, and 219 g/kg MSo respectively). The lowest methane yield (methane per kg of DMI) was also observed for the MSS cows (15.5 g/kg), whereas there was no difference between the PRG and PRGWC cows (17.6 and 17.7 g/kg, respectively). Greater VFA concentrations were observed for both the MSS and PRG cows compared with the PRGWC cows, whereas the MSS cows had a greater butyrate proportion compared with the cows grazing both other sward systems. Breed also had a significant effect on both milk and methane production characteristics with JFX animals having increased fat and protein concentration and increased MSo production compared with HF. The JFX cows also had reduced BW. Breed had no effect on DMI or methane yield, but JFX also had improved feed efficiency, both per kilogram of DMI and per kilogram BW. The HF cows had an increased methane intensity (223 g/kg MSo) compared with JFX (207 g/kg MSo). Rumen ammonia concentration and acetate-to-propionate ratio were increased for JFX, whereas VFA propionate proportion was decreased, and butyrate proportions were increased compared with HF. The results of this study highlight the potential for more diverse swards and Holstein-Friesian × Jersey crossbreeding to reduce enteric methane emission intensity within pasture-based dairy systems.
Description
Keywords
Breeding , Clover , Environmental sustainability , Multispecies , Pasture-based milk production system
Citation
Dwan, C., Horan, B., Buckley, F., Jezequel, A., Costigan, H., Delaby, L., Galvin, N. and Lahart, B. (2025) 'The effect of increasing sward species diversity on enteric methane emissions from Holstein-Friesian and Holstein-Friesian× Jersey crossbred dairy cows in a rotational grazing system', Journal of Dairy Science, 109(1), pp. 420-436. https://doi.org/10.3168/jds.2025-27375