Late lactation planning for your herd
Autumn is an important time for setting the herd up for winter and spring calving. Milk production and body condition are dependent on feed quality as well as quantity.
The average days a cow is in milk in New Zealand is 220 days a year¹, though the animal is capable of lactating for 305 plus days. The short lactation lengths are due to multiple factors including feed shortages and/or poor-quality feed in late lactation, facial eczema challenges, heat stress, mycotoxins, poor cow condition and low cow production in late lactation.
Significant gains, such as improved production and achieving body condition score (BCS) targets, can be achieved by planning for better late lactation management. This can include feeding quality supplements to fill specific nutrient deficiencies. By doing so, the cow will maintain good body condition and therefore be better able to tolerate adverse events, have improved feed conversion efficiency and be able to cope with deficiencies in the ration.
Ideally, mixed-aged cows are dried off at a BCS of 5.0. Early autumn is an ideal time to be working towards this goal as it takes time to gain condition. Additional supplementation, either grown on-farm, such as maize silage, or as bought-in feed, is a way of helping improve the BCS of the herd. Other farm strategies can be implemented to reduce demand so consider milking once a day or drying lighter and low-producing cows off early.
Lush autumn pasture can lift milk production, but often at the cost of BCS. This is due to the increased protein and energy content of the pasture. When feeding quality autumn grass, high starch/low protein supplements such as maize silage or grains help to balance the herd’s diet, by providing good energy for BCS gain whilst reducing protein in the diet.
Heat stress negatively impacts feed intake and milk production by decreasing both fat and protein yield. As high-producing dairy cows are more vulnerable to heat stress, nutritional strategies can be used to minimise the impact. These strategies can be feeding high-energy, low fibre feeds or using feed additives such as live yeasts, mycotoxin binders and rumen buffers.
Other important management strategies include providing shade and reducing the distances walked in the heat of the day. Providing access to clean water is essential too, with cows often drinking more than 100 L of water per day on warm days.
Contact your local PGG Wrightson Technical Field Representative for advice on suitable nutritional supplements for your herd.
1 Dairy NZ. (2021). New Zealand Dairy Statistics 2020-21. Retrieved 11 January 2023 from https://www.dairynz.co.nz/media/5794941/nz-dairy-statistics-2020-21-web.pdf.