Arjan Jonker




PhD Animal Nutrition, University of Saskatchewan, Saskatoon, Canada

MSc Animal Nutrition, Wageningen University, Wageningen, the Netherlands

Research interests & activities

  • Ruminant nutrition
  • Dairy, beef and sheep production
  • Feed/forage evaluation
  • Enteric methane mitigation through feeds/forages
  • Ruminant methane measurement methods
  • Animal variation in methane emissions


Jonker A, Molano G, Sandoval S, Taylor PS, Antwi C, Olinga S, Cosgrove GP. 2016. Methane emissions differ between sheep offered a conventional diploid, a high sugar diploid or a tetraploid perennial ryegrass cultivar at two allowances at three times of the year. Animal Production Science (In Press).


Jonker A, Molano G, Muetzel S. 2016. Methane emissions from lactating and non-lactating dairy cows and growing cattle fed fresh pasture. Animal Production Science (In press).



Waghorn GC, Jonker A, MacDonald KA. 2016. Measuring methane from grazing dairy cows using GreenFeed. Animal Production Science 56:252-257 (
Henderson G, Cox F, Ganesh S, Jonker A, Wayne Y, Global Rumen Census Collaborators, Janssen PH. 2015. Rumen microbial community composition varies with diet and host, but a core microbiome is found across a wide geographical range. Scientific Reports. 5, 14567 (http://dx.doi: 10.1038/srep14567).
Kittelmann S, Kirk MR, Jonker A, McCulloch A, Janssen PH. 2015. Buccal swabbing as a way to determine bacterial, archeael, and eukaryotic community structure in the rumen of sheep. Applied and Environmental Microbiology. 81:7470-7483 (http://dx.doi:10.1128/AEM.02385-15).
Jonker A, Muetzel S, Molano G, Pacheco D. 2015. Effect of fresh pasture forage quality, feeding level and supplementation on methane emissions from growing beef cattle. Animal Production Science (
Jonker A, Molano G, Antwi C, Waghorn GC. 2014. Feeding lucerne silage to beef cattle at three allowances and four feeding frequencies affects circadian patterns of methane emissions, but not emissions per unit of intake. Animal Production Science. 54:1350-1353 (
Jonker A, Cheng L, Edwards G, Molano G, Taylor P, Sandoval E, Cosgrove GP. 2015. Nitrogen partitioning in sheep offered three perennial ryegrass cultivars at two allowances in spring and autumn. Proceedings of the New Zealand Society of Animal Production. Vol 75:74-78. 
Cosgrove GP, Taylor PS, Jonker A. 2015. Sheep performance on perennial ryegrass differing in concentration of water soluble carbohydrate. Proceedings of the New Zealand Grassland Association, 77:123-129. 
Jonker A, Lowe K, Ledgard S, Pacheco D. 2014. Graded substitution of lucerne silage by maize silage or maize grain results in a quadratic response in methane emissions from sheep. Animal Production in Australia 30:73.
Jonker A, Molano G, Sandoval E, Taylor P, Cosgrove GP. 2014. Methane emissions by sheep offered high sugar or conventional perennial ryegrass at two allowances. Proceedings of the New Zealand Society of Animal Production 74:145-147.
Cosgrove GP, Taylor PS, Lowe K, Jonker A. 2014. Milk urea estimates of nitrogen excretion by dairy cows grazing forage species with contrasting chemical and morphological characteristics. Proceedings of the 5th Australasian Dairy Science Symposium, pp 249.
Jonker A, Pacheco P. 2013. In vitro ruminal fermentation and methane production from maize silage mixed with high or low quality ryegrass at five inclusion levels. Proceedings of the New Zealand Society of Animal Production 73:202-204.