@conference {4185,
	title = {BRIEF COMMUNICATION: Adaptation of grazing sheep to GreenFeed emission monitoring units under New Zealand ryegrass-white clover pastures},
	booktitle = {Hamilton},
	volume = {85},
	year = {2025},
	pages = {27-31},
	address = {Hamilton},
	abstract = {<p>GreenFeed (GF) emission monitoring units have been extensively used in cattle, but few studies have been conducted using sheep in pastoral grazing situations. This study aimed to investigate ewe visiting behaviour in the presence of GF units and the successful collection of methane (CH$_{4}$) measurements. Commercial sheep pellets were introduced to 156 na{\"\i}ve two-tooth Romney ewes at an allocation of 130 g/ewe/day. From those, 76 frequent pellet consumers were selected for introduction to three GF units. Out of those, 22 (28.9\%) exhibited daily visits and a good stay duration (>=2 minutes) per visit at the GF units, allowing for valid CH$_{4}$ mass flow calculations. In total, the GF units were visited an average of 42.8 {\textpm} 14.9 times daily, making 4.6 {\textpm} 1.12 visits/ewe/day by the 22 frequent users. The average duration of successful CH$_{4}$ emission measurement was 5:32 {\textpm} 3:21 minutes/visit. The calculated average total CH$_{4}$ emissions were 30.02{\textpm}5.52 g/d. The study provided valuable insights into the behavioural variability and engagement levels of ewes with GF units, along with functionality and feeding aspects of the three GF units. Further, the study highlighted key challenges in training ewes and pellet consistency, which should help improve the understanding of measurement variability to support more reliable use of GF systems in grazing settings.</p>
},
	keywords = {enteric methane, ewe behaviour, GreenFeed units, pellet standardisation, sheep},
	author = {R.N.N. Weerasinghe and A.K. Almeida and D.J. Horne and L. Burkitt and P.R. Kenyon and L.M. Cranston}
}
@conference {4182,
	title = {BRIEF COMMUNICATION: Nitrate leaching under sheep and beef cattle grazing},
	booktitle = {Hamilton},
	volume = {85},
	year = {2025},
	pages = {16-19},
	address = {Hamilton},
	abstract = {<p>In recent years, there has been increased concern about the contamination of waterways with nutrients, in particular the nitrate-N (NO$_{3}$$^{-}$) leached from pastoral farms (Ministry for the Environment 2020). At higher concentrations (\&gt;11.3 mg N/L), nitrate-N can be hazardous to human health and aquatic life (Di \&amp; Cameron 2002). Nitrate-N leaching is known to be high under dairy cattle grazing, however, there has been little research to quantity nitrate-N leaching under sheep and cattle grazing, particularly in recent times. This study compared nitrate-N leaching under sheep and beef cattle grazing perennial ryegrass/white clover. It also investigated whether mixing Italian ryegrass with brassica can mitigate nitrate-N leaching relative to a brassica monoculture crop under sheep grazing. The measured rates of nitrate-N leaching were also compared with predicted values using Overseer. Twenty plots were sown in four treatments each with five replicates: sheep grazing perennial ryegrass/white clover, sheep grazing turnips/Italian ryegrass, sheep grazing kale, and rising one-year cattle (R1) grazing perennial ryegrass/white clover. Measured leaching losses under all treatments were small and there was no significant difference (P\&gt;0.05) in the nitrate-N leaching flux between treatments. The Overseer estimates of nitrate-N leaching were greater than the observed values. Further, Overseer modelling also predicts that there would not be differences in the leaching losses observed under sheep and R1 cattle grazing.</p>
},
	keywords = {Beef Cattle, Nitrate Leaching, sheep},
	author = {F.F.M. Algharibeh and L.M. Cranston and J.P. Millner and P.R. Kenyon and P.C.H. Morel and D.J. Horne}
}
