Average pasture cover (APC)

Achieving target APC at calving is important for meeting feed demand and for pasture growth rate and quality. APC at calving determines how cows are fed in their first two months after calving.

Feed allocation/BCS

Feed allocation after calving has only small effects on BCS (body condition score). BCS should be:

• Cows: 5.0 at calving 4.0 at mating
• Two- and three-year-olds: 5.5 at calving 4.5 at mating

Feed allocation

From the start of calving, prioritise feed allocation to colostrum cows, then milkers, then springers, then dry cows. Dry matter (DM) feed intake potential at calving is significantly less than cows’ peak intake potential which is 7-10 weeks after calving.

Spring Rotation Planner (SRP)

Use the SRP to guide pasture allocation; manage grazing rotation speeds, pasture cover decline rates and pasture quality; and minimise pasture deficits.

Pasture residuals

Repeated low pasture residuals indicate an energy deficit, while repeatedly high residuals show too much pasture is being allocated. Aim for 1500 to 1600 kilograms of DM per hectare (kg DM/ha) at each grazing.

Supplements

In a pasture-based system, supplementary feeds should be used only to fill an energy deficit in early lactation (as indicated by grazing residuals). Don’t use them to balance the nutritive value of your cows’ diet.

Minerals

Calcium (Ca) and magnesium (Mg) are key minerals used over spring to decrease cows’ metabolic issues during transition. Supplement Mg from 2-3 weeks pre-calving until 4 months postcalving. Ca is usually only needed in the few days immediately post calving.

Grazing intervals

The proportion of the farm grazed daily is measured as rotation length: it sets the grazing interval (number of days between a paddock’s first and second grazing after calving). If too short, pasture growth is reduced.

For more info on seasonal pasture and feed management see dairynz.co.nz/pasture

Other useful links

• dairynz.co.nz/soil-fertility
• dairynz.co.nz/SRP
• dairynz.co.nz/BCS
• dairynz.co.nz/supplements
• dairynz.co.nz/magnesium

This article was originally published in Inside Dairy August 2019