New Zealand Dairy Farmers Manage Pastures for Peak Milk and Persistence
Spring management during the balance-date period and early lactation is being highlighted as a key part of dairy-farm operations in New Zealand. Grazing specialists say farmers need to match cow intake with pasture quality while ryegrass shifts from vegetative growth towards reproduction. Appropriate grazing intervals help maintain metabolisable energy in the diet and preserve perennial tiller density for the summer period.
Technical recommendations centre on both pre-grazing covers and post-grazing residuals. Suggested pre-grazing covers are 2,800–3,000kg of dry matter per hectare, a range intended to provide cows with leafy, high-energy ryegrass before the sward develops more fibrous stems. Post-grazing residuals are recommended at 1,500–1,600kg of dry matter per hectare, equivalent to about 3.5–4cm of compressed height or seven to eight clicks on a rising plate meter.
Maintaining those residuals is intended to support full pasture use without excessive grazing. Over-grazing reduces plants’ root carbohydrate reserves and can slow recovery. Once cows are milking, regular pasture measurement and weekly farm walks can identify paddocks with either a surplus or a shortage before those conditions affect the rotation.
Ryegrass reproductive growth becomes an operational issue as daylight hours lengthen and temperatures rise in October and November. When seedheads appear, pasture quality declines, with lower metabolisable energy and higher neutral detergent fibre. Agronomists advise farmers to identify paddocks that have moved beyond the desired pre-grazing range and remove them from the milking rotation for silage or baleage.
Early removal of surplus paddocks keeps the grazing rotation tighter and limits the herd’s exposure to mature, lower-protein seedheads. The guidance links this practice to peak milk-solids production, although the article does not provide a national production figure or a specific farm-level result.
Pasture management also affects the development of new ryegrass tillers. Daughter tillers that emerge in late spring replace parent tillers after flowering. If a sward becomes tall and shaded, young tillers at its base may receive less light and die, leaving paddocks more open and vulnerable to weed ingress during summer droughts. Consistent residuals allow more light to reach the plant crown and support tiller formation.
Feed testing identifies leafy spring pasture as the lowest-cost feed source for pastoral dairy systems in the article’s comparison with purchased concentrates, measured on a cost-per-megajoule basis. The recommended programme combines controlled rotation lengths, weekly cover assessments and prompt action on surplus paddocks. The source is Farmers Weekly NZ.
