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    This resource provides explanations of the key concepts and terms encountered when exploring some of the science that supports sustainable dairy farming.

    Cultivar

    A plant variety selectively bred for its desirable characteristics.

    Dairy effluent

    The wastes and wastewater collected during the management of livestock on a dairy farm. If used effectively, effluent is a valuable reuse of nutrients for pasture growth.

    Dry matter

    The material remaining after feed, such as pasture plants, has had the moisture content removed. It’s also a measurement of the mass of something when the water is removed. For example, feed quantity is commonly measured in kilograms of dry matter.

    Fermentation

    The chemical breakdown of molecules like glucose and other carbohydrates in the absence of oxygen. In ruminants, microbial populations ferment feed and water into volatile fatty acids and gases – methane and carbon dioxide.

    Forage

    A collective term for plant material eaten by grazing livestock. It includes pasture plants like grasses, legumes and herbs as well as plants that are cut and carried to the animals such as silage, maize or hay.

    Methane

    Methane (CH4) is a greenhouse gas. Globally, the leading sources of human-influenced methane emissions are from primary production – with the majority from livestock and rice production.

    Milk products

    New Zealand dairy companies produce a full range of dairy products – everything from milk powder, butter and cheese to infant formula, speciality creams for bakers and specialist nutritional products for medical and sports nutrition.

    Nitrous oxide

    Nitrous oxide (N2O) is a gaseous byproduct emitted as part of the nitrogen cycle. A large proportion of these emissions come from agricultural soils as soil microbes break down urine, dung and nitrogen fertilisers. It is a greenhouse gas.

    Pasture

    Plants grown for the feeding of grazing animals. In Aotearoa New Zealand, common pasture plants are perennial ryegrasses, white and red clover, tall fescue, cocksfoot, lucerne, plantain and chicory

    Plantain

    A herb commonly found around the world. In dairy farming, upright-growing cultivars are used as part of mixed pasture or as a special-purpose crop. In addition to its usefulness as a quality feed source, scientists are investigating plantain as a way to mitigate water quality issues and greenhouse gas emissions.

    Ruminant animals

    Mammals such as cattle, sheep, deer and camels that have a complex stomach with three or four chambers that uses a fermentation process to break down carbohydrates in their plant-based diet.

    Rumination

    The process of rechewing the cud (a bolus of semi-degraded food that has been chewed and mixed with saliva) to further mechanically break down plant material.

    Sward

    A grassy surface of land. Another word for pasture. A mixed sward is made up of several plant species such as ryegrass, clover and plantain.

    Related content

    Additional terms related to science and farming are in Soil, farming and science – key terms.

    Dairy innovations – targeting climate change introduces a suite of resources exploring forage research in the dairy sector.

    Dairy farming and climate change – a context for learning provides curriculum links, te ao Māori perspectives and an interactive planning pathway to help teachers get started.

    The Hub features other DairyNZ research on robotic milking.

    Acknowledgement 

    This resource has been produced with the support of DairyNZ.

      Published 15 April 2021 Referencing Hub articles