Efficiency Under Pressure: Supporting Herds Through Autumn Challenges

Autumn 2025 is set to be a challenging period for dairy farmers in parts of the UK, as an exceptionally dry summer has left many farms short of usable forage. Pasture quality also drops during the autumn months, resulting in less nutritional value from grass, and this variability in pasture quality increases the risk of grass staggers. Add to this the demands of transition to housing and there’s little slack in the system. In short, efficiency now matters more than ever in order to protect the productivity of your herds and maximise milk yields. 

Forage Stocks Under Strain 

Seven consecutive months of below-average rainfall left grass growth stunted across much of the UK. During the summer, Farmers Weekly reported widespread concern over fodder shortages, while BBC News highlighted dairy farmers in the West Country feeding winter rations months earlier than planned, as parched pastures failed to deliver any nutrition. Reservoir storage across England has fallen to worrying lows, with many regions still officially in drought in early September. 

This has forced many to draw on silage stocks well ahead of schedule. With reserves already under pressure, there’s a real risk that winter forage will run out before spring growth arrives. 

Managing Autumn Grazing 

With forage tight, making the most of the remaining autumn grass is essential. Yet declining quality and variable weather present significant hurdles. As the nights draw in, grass fibre content rises while sugars and energy fall, making it less viable to support lactating cows without supplementation. 

Planning autumn pasture rotations carefully and adopting on/off grazing can help stretch what’s remaining. Rotating cows between pasture and housing not only maximises the use of what grass is left but also helps protect soil structure in wet conditions.  

Introducing buffer feeding gradually is equally important. Remember to adjust cow nutrition gradually to allow the cow’s rumen microbial populations to adapt. Prioritise fresh-calved cows for housing first, with late lactation cows the last to come in, to balance energy supply with demand. 

Grass Staggers: An Autumn Threat 

During the autumn months, the risk of grass staggers (hypomagnesaemia) rises for lactating cows at pasture. This potentially fatal condition, caused by magnesium deficiency, can strike fast and sometimes without obvious warning. 

Early signs include restlessness, high head carriage, muscle twitching and an over-alert or excitable appearance. In severe cases, cows collapse, convulse and may die without intervention. Treatment requires urgent veterinary attention, typically involving magnesium injections. However, prevention is always preferable. 

Avoiding high-potash fertilisers, supplementing magnesium daily (for example via licks, water or minerals), and working with your nutritionist to ensure intakes meet demand are all key strategies. NADIS guidelines recommend 2.5 g/kg DM of magnesium for lactating cows at grass. Remember: cows cannot store magnesium, so they are reliant on the magnesium they receive daily in their rations. 

The Efficiency Solution 

During challenging periods when every kilo of forage counts, feed efficiency should be a top priority. In simple terms, feed efficiency is a performance indicator for the amount of milk produced per unit of dry matter intake (DMI). Improving it means producing more milk from less feed, reducing waste and making better use of resources across your farm. 

This is where rumen-protected fats like Megalac can help. Fat is one of the most effective nutritional supplements to increase energy density in the ration, providing around 2.5 times the energy concentration of cereals. Rumen-protected fats pass through the rumen and deliver concentrated energy directly to the small intestine, allowing nutritionists to formulate higher energy density diets to support milk yields, fertility and body condition, without adding to the acid load in the rumen that we would get from starchy sources of energy, such as cereals, leading to potential acidosis issues. 

For autumn-calving cows in early lactation, the challenge is to improve body condition score and get back in calf. As a general rule, each one-unit loss in body condition score will reduce conception rates by about 10%. During this early lactation period, C18:1 (oleic acid) is the key fatty acid to deliver to the small intestine for absorption as the latest research demonstrates its effect on insulin status, increasing partitioning of energy and nutrients to improve body condition. 

Action Plan for the Autumn Transition 

Autumn 2025 will undoubtedly be another testing time for many UK dairy farmers. Forage shortages, declining pasture quality and seasonal herd health risks will all pose key challenges to overcome in the months ahead. But with careful planning, proactive grazing and supplementation strategies and a focus on feed efficiency, it’s possible to sustain herd health and performance through the season: 

1. Assess your forage stocks now: calculate reserves and plan accordingly. 
2. Adopt on/off grazing: stretch available grass while protecting soil and pasture health. 
3. Prioritise vulnerable cows: house fresh-calved cows first to maintain condition. 
4. Prevent grass staggers: supplement magnesium daily and stay vigilant for early warning signs. 
5. Introduce buffer rations gradually: transition cows steadily to housed diets. 
6. Feed rumen-protected fat: increase ration energy density, supporting fertility, milk yields and body condition. 

By taking these steps, you can protect your herd’s health, performance and fertility, and set your herd up for resilience in the months to come. Looking for advice on managing your herd’s performance this autumn? Get in touch with the Megalac team here.