Following a summer where many farms have experienced prolonged dry conditions, attention is now turning to the quality and consistency of late-season grazing. While recent rainfall may have encouraged grass growth, stressed pastures can present nutritional challenges, including lower digestibility, increased fibre levels and variable nutrient supply.
Understanding how these changes affect rumen function is key to maintaining performance through autumn and preparing cows for winter. Generally, as dry matter intakes reduce in late summer, rumen efficiency and forage digestibility can also decline. So, at a time when grazing quality is past its peak, what can we do to support the rumen and set ourselves up for a strong winter? In fields affected by summer drought, grazing quality can be particularly variable. Grass may be more mature and fibrous than normal, with elevated NDF levels and reduced digestibility. Even where rain has stimulated fresh growth, cows may be grazing a mixture of older stemmy material and lush regrowth, creating inconsistency in nutrient supply. When forage quality becomes less predictable, maximising nutrient utilisation from every kilogram of dry matter becomes increasingly important. Utilising as much of the energy available as possible is important to maintaining milk yield and body condition in late summer. One tried and tested solution to this is a live yeast, such as Yea-Sacc®.
Live yeasts are proven to help degrade fibre in the rumen. One mechanism of this is oxygen scavenging, where the yeast cells consume residual oxygen and establish strict anaerobic conditions. These conditions are then perfect for fibre-digesting bacteria to break down the plant cell walls and produce acetate. This enhanced production of acetate is ideal for late summer, as acetate supports healthy recovery of butterfat levels at a time of year when they are often depressed. This mechanism shows how feeding live yeast can not only help with butterfat production, but also produce a healthier, more optimal rumen. Research conducted by Alltech has demonstrated milk yield improvements of approximately 0.5 litres per cow per day under certain feeding conditions. Along with feeding a yeast, NWF have developed multi-purpose Farm Paks to provide the perfect cocktail of supplements needed within the herd, combined into one cost-effective solution.
An example of this, which is perfect for late-season grazing is the NWF Healthy Rumen Farm Pak. This Pak combines a live yeast with a buffer to give tailored support to the rumen of grazing dairy cows. Already containing the benefits of a live yeast, the rumen buffer also helps control pH challenges. Fluctuating rumen pH can be a challenge in late summer due to inconsistent pastures which can cause unbalanced acid loading on the rumen. This often happens when pastures are stemmier, burnt off or undergo rapid sugar shifts due to weather changes. The combined effect that yeast and rumen buffer have on digestibility and pH stabilisation makes it the perfect supplement to feed to late grazing herds.
In summary, supporting the rumen during the late grazing season is essential to maintain milk yields and body condition, ensuring cows come inside in peak condition and ready to perform throughout the winter. Failure to do so can lead to milk losses, reduced butterfat levels and declining body condition as nutrient absorption becomes less efficient and intakes fall. Following a difficult growing season, maintaining body condition and milk solids through autumn is particularly important. Any loss in condition now can be difficult and costly to recover once cows are housed.
Speak to your local NWF sales specialist to discuss the solutions available for your system and how targeted rumen support can help maintain performance, protect body condition and set your herd up for a productive winter.