Peaking ahead into winter

Off the back of a wet summer and autumn, you might expect that we would be heading into winter with big smiles on our faces, secure in the feed wedge that has built up and basking in the glory of the high-quality feed that is growing in the paddocks and milk that is flowing in the vats. If this is where you find yourself, stop reading! This article is not for you.

It is not uncommon to find autumn herds struggling to produce to expectations this season with a wide variety of underlying factors. Of the feed situations causing production angst this autumn, here are five of the most common:

As paradoxical as it sounds to have lower covers after this wet summer compared to last season’s drought, we saw a lot of supplements fed last year and farmers protecting their covers heading into calving and early lactation. With the arrival of rains in late May 2022, pasture bolted and covers built quickly while supplement feeding remained high. This season, pasture has been eaten as fast as it has grown, a good thing giving profitable production. But waterlogged pastures have not grown as fast as expected in the late autumn and forage supplementation has been delayed for a variety of reasons depending on the infrastructure on farm resulting in lower covers on some farms.

When pastures grow rapidly following a drought, as they did last season, it is common to see ME values of 11.5MJME/kgDM or more. The energy content of pastures we have sampled in Kaiaua, Waerenga, Rangiriri and Mangatawhiri over May/June 2023 are consistently returning MJME/kgDM values beginning with a 10 not an 11. This represents a drop of about 11% in combined energy content and efficiency of conversion to milk solids from the same kgDM of pasture. Assuming pasture is contributing 14kgDM/c/d this change in energy content and efficiency is worth 0.2 to 0.3kgMS/c/d in a well-producing herd.

We are also seeing pastures higher in fibre. This reduces the amount of energy that a fully fed cow can consume, in turn reducing milk production. This is often seen as high residuals in the face of poor production.

Water-logged pastures may also reduce the level to which cows will graze. This may be because the waterlogging is sufficient so that cows literally must eat underwater to clean up the break, something they are reluctant to do. Also, pasture contamination with mud, faeces and tramping is much quicker to occur in wet paddocks than in drier paddocks quickly reducing the palatability of the feed in the break.

Behavioural patterns of cattle well used to heading to the feed pad for the more consistent part of their diet is also influencing intakes on some farms. Instead of continuing to graze pasture that is available, they are hanging out by the gate waiting for the batt-latch to let them access the pad.

To improve the production and help cows perform to target ahead of mating, multiple strategies are needed including the following and sometimes contradictory strategies:

increased forage supplement;
high-quality concentrate supplementation;
increasing the number of breaks set per day;
intentional substitution of pasture;
reduction of fibre in some herds and increasing fibre in others.

With the variety of problems identified this season, it is a season to bring out the whole toolbox and get creative in ensuring your autumn herd performs well. There are very few rules to fit all situations this season, so if you want some specific insights into your herd, feel free to call one of our team to assist.

Dr David Hawkins - Farm Vet in the South of our practice