Time4Formulating: Autumn Dairy Cow Diets

Autumn Dairy cow Diets

You’ll likely already know that balancing nutritional intakes of a dairy herd, while maintaining health and yields, is a priority for all farmers during the autumn.

As cows settle on to winter rations, diet changes need to be gentle and gradual to avoid impacting on rumen stability, health and performance. A gradual change will also have a positive impact on the digestive utilisation of vital homegrown forages, helping keep on top of bought-in feed quantities.

To help you successfully transition into autumn/winter, our experts are here with their practical top tips:

Assess silage stocks

Brought-in feed is the most expensive aspect of milk production (up to 40% of total costs) so maximising the use of home-grown bulk fodder is often the lowest cost option for housed cows. However, it’s important to analyse the quality of this forage on a regular basis to optimise nutrient utilisation and rumen function, and to balance winter feed plans as there can be significant variation as you work back through each cut/clamp.

As a rough guide a 650kg Holstein cow in milk will eat around 20 – 24kg dry matter per day.  Of this around 50% should be forage. The dry matter of the silage will determine how much fresh weight of silage they will eat in a day. This season we have seen a wide range of dry matter in grass silage, from below 20% to over 50%. 

Once the quality of forage is determined using the analysis results, shortfalls in nutritional requirements can be balanced using custom blends or compounds, that suit your farm system and milk contract, and adapted over time as forage quality and fermentation characteristics change.

Additionally, the best or poorest quality forage can be allocated to different cows within the herd, depending on their needs. For example, far off dry cows will need to be fed a maintenance diet that provides minimal but adequate energy. This means they can be fed more mature forages that have a low digestibility value.

Silage quantities should also be assessed to ensure calculations can be made as to how far it will stretch over the housing period to help determine whether forage replacers need to be purchased. 


Consider buffers and yeasts

It takes the microflora in the rumen three weeks to adjust to ration changes, meaning digestion won’t be as efficient as it should be during this time.

Instability in the rumen environment and microbial population can also reduce feed intakes, leading to a decline in performance and butterfat levels.

It’s therefore worth considering incorporating a yeast or rumen conditioner such as TechTonic™ into the ration during this nutritional transition period.

Both will help support rumen function and stability, prevent issues such as subacute ruminal acidosis (SARA), and support better feed conversion efficiency (FCR).

  • Yeasts improve the conditions in the rumen by stimulating the growth and activity of forage digesting bacteria
  • Rumen buffers help to re-establish rumen pH within the ideal range of 5.8-6.2

Support immunity

Sufficient levels of minerals and vitamins in the right balance need to be fed for performance and immunity.

If you choose to use supplementary products, such as licks, blocks or powders when formulating feed rations, it’s important to choose those that have been created to industry standards and comply with Maximum Permitted Levels. This will reduce the risk of excess intakes which in turn can cause health issues.

For example, high intakes of copper can cause chronic copper toxicity leading to a significant reduction in milk production or death. Don’t kill with kindness!

For more information on managing diet changes as cattle are housed, contact your local on-farm specialist or dairy nutritionist.