@article {3672,
	title = {BRIEF COMMUNICATION: Greenhouse gas emissions from New Zealand sheep-and-beef farm systems},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {79},
	year = {2019},
	month = {07/2019},
	pages = {56-60},
	address = {Palmerston North},
	abstract = {Agriculture was the single largest contributor (48.1\%) to total greenhouse gas (GHG) emissions in New Zealand in 2017, and sheep and beef livestock systems contributed about 40\% of these emissions. A holistic assessment of the farm-scale drivers of GHG emissions is critical to identifying opportunities to reduce emissions. We used farm-scale models to estimate feed inventories, nutrient flows and GHG emissions for 60 sheep and beef farms. The range in annual GHG emissions (methane (CH4) and nitrous oxide (N2O)) was 189 to 6,362 kg carbon dioxide (CO2) equivalents per hectare, demonstrating the diversity in sheep and beef systems. As stocking rate and animal product (wool + net carcass weight) per hectare increased, GHG emissions increased, although some farms exhibited 50\% higher emissions than others with similar animal product per hectare. The variation in GHG emissions across these farms indicates there is potential to reduce on-farm GHG emissions and remain productive and profitable.},
	issn = {1176-5283},
	author = {Hutchinson KJ and Rennie GM and Vibart RE and Mercer GJK and O{\textquoteright}Neil K and Burtt AN and Chrystal JM and Devantier B and Smiley DR and Taylor AL and Thompson BR and Wall AJ and Dynes RA}
}
@article {3672,
	title = {Carbon footprint of two unique farms, compared with industry averages},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {79},
	year = {2019},
	month = {07/2019},
	pages = {118-124},
	address = {Palmerston North},
	abstract = {Three years of data from a North Island breeding property (Onetai) and a South Island finishing property (Highlands) were modelled in Farmax and Overseer{\textregistered}, to estimate production, profitability and GHG emissions. On an annual basis, each hectare of Onetai averaged more than 100 kg meat and 25 kg of fibre across three years, worth $420/ha. On Highlands, each hectare produced 200 to 327 kg of meat and 20 kg of fibre, with revenue on average $737/ha, but varying between $433/ha in a drought and almost $900/ha in better seasons. GHG emissions (in CO2 equivalents CO2-e) ranged from 3106 to 3302 kg/ha at Onetai, and from 3043 to 5067 kg/ha at Highlands. The dramatic variation on the finishing farm was due to varying numbers of store stock purchased and finished according to available forage. Industry data for similar class farms modelled using the same software averaged around 3600 kg CO2-e /ha. Similar farms ($339/ha) were less profitable than Onetai, and finishing farms were less profitable than Highlands ($467/ha). Per hectare, all farms emitted similar amounts of GHG to literature values, but study farms produced more meat and greater financial returns. Greater efficiency of production is better for the pocket and the planet.},
	issn = {1176-5283},
	author = {Dynes RA and Scobie DR and Vibart RE and Rennie G and Hutchinson KJ and Taylor A and Moss RA and Dennis S and Wall A}
}
@conference {78995,
	title = {In vitro fermentation of [15N-] ryegrass and ruminal digesta of sheep grazing a ryegrass-based pasture in the morning or in the afternoon},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {72},
	year = {2012},
	month = {Jan},
	pages = {100-105},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {<p>Sheep in many areas of Australia and New Zealand experience periods of variable feed supply. Merino sheep can be bred to be more resilient to this varying feed supply. Resilient sheep lose less live weight when grazing poor quality pasture. However, we do not know if breeding for live weight change genetically affects reproduction. To estimate genetic correlations between live weight change and reproduction we used information from 6,870 fully pedigreed Merino ewes aged two- to four-years-old. Liveweight change was measured during joining (42 days) on low quality pasture and during lactation (130 days) on high quality pasture. Reproduction traits were total weight of lambs born and weaned and binary traits of whether or not a ewe gave birth to, or weaned, a lamb. Genetic correlations between live weight change and reproduction within age were estimated. There were moderate to high genetic correlations between live weight loss during joining and the chance of having and weaning a lamb. All other correlations were low. Therefore, change in live weight during joining affects the chance of having a lamb but not the weight of those lambs.</p>
},
	issn = {1176-5283},
	author = {Vibart RE and Tavendale MH and Burke JL and Pacheco D}
}
@conference {75912,
	title = {Ruminal fermentation characteristics from sheep offered a fresh grazing allocation of a ryegrass-based pasture either in the morning or in the afternoon},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {71},
	year = {2011},
	month = {Jan},
	pages = {234-239},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Invercargill},
	abstract = {Eight rumen-fistulated wethers were used to examine the effects of PM (16:00 h) versus AM (08:00 h) allocation of spring herbage from pasture on aspects of ruminal metabolism that lead to increased utilisation of nutrients. The experimental period consisted of two phases; adaptation to diets and intensive sampling. During the adaptation phase, total volatile fatty acids (VFA) and ammonia concentrations were greater for the PM group, whereas the ratio of non-glucogenic to glucogenic VFA did not differ. These results suggest greater fermentation from forage that had similar concentrations of crude protein, neutral detergent fibre, and water soluble carbohydrates, but greater organic matter digestibility (84.1 vs. 82.3\%). During the intensive sampling phase, the mean total VFA and ammonia concentrations did not differ among groups, but the 24-hour pattern varied considerably for all variables measured. Unseasonal weather conditions during the trial were associated with smaller differences in water soluble carbohydrate accumulation than expected. Based on our results, at least four hours of sunshine were needed to obtain diurnal differences greater than 20 g per kg herbage DM. The implication of these findings on the implementation of nutritional management strategies warrants further investigation.},
	issn = {1176-5283},
	author = {Vibart RE and Burke JL and Pacheco D}
}
@conference {60974,
	title = {Exploring the relationships between plant chemical composition and nitrogen partitioning in lactating dairy cows fed ryegrass-based diets},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {69},
	year = {2009},
	month = {Jun},
	pages = {188-195},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Data from experiments in which cows consumed ryegrass-based diets were used to evaluate the effects of plant constituent concentrations and nutrient ratios on the partitioning of nitrogen (N) secreted into milk and excreted as waste products (urine + faeces). The data set used from 32 publications with 170 treatment means, was derived from studies where freshly-cut or grazed pasture comprised more than 70 \% of the total diet on a dry matter basis. The objectives were to identify suitable predictors of N partitioning, both across and within studies, and to examine the relative weight these predictors have on the partitioning of dietary N. Total excretion of N (g/d) and urinary N (g/d) were best predicted by the single predictor crude protein concentration, but better relationships were obtained by adding water soluble carbohydrate (WSC) and neutral detergent fibre concentrations to the models. Although significant across studies, no single plant constituent variable was selected using the meta-analytical approach. The most reliable predictions of N in waste products and urine required measures of N intake for urinary N excretion, or in combination with total OM intake for total N excretion. },
	issn = {1176-5283},
	author = {Vibart RE and Koolaard J and Barrett BA and Pacheco D}
}
