Beat the Drop:Manage and maintain butterfat in mid-lactation.

A decline in butterfat percentages can be common during the early summer months, when cows are grazing lush grass that is low in fibre and high in oil and sugars, among other reasons.

Tuesday, 8th June 2021, 8:21 am
Richard Dudgeon, of Alltech
Richard Dudgeon, of Alltech

When it comes to combating this potential drop in butterfat, the Alltech nutritional team focuses on four key areas of management: nutrition, rumen health, grassland management and genetics.

1. Nutrition

We generally see a high percentage of solids for the first six weeks post-calving, then a drop in protein and butterfat replicated further on in the lactation. If protein percentages are fluctuating or dropping quickly, this is usually a symptom of reduced intake of energy, which leads to poor body condition and prolonged negative energy balance post-calving.

“It is important to maintain a body condition of greater than 2.75 or avoid a drop greater than 0.5 units post-calving until breeding,” Alltech’s regional manager for Northern Ireland, Richard Dudgeon, explained.“If below this, action must be taken to correct it as, on top of a butterfat drop, there could be adverse effects on fertility.

“Protein percentages will also be driven by the quality of feeds fed in the form of starch and sugar content, and the total quantity of these ingredients or dry matter intake (DMI). Starch content usually coming from grain and sugar content will be high in grazed grass.

“Cows should be fed to their requirements consistently. For example, a cow that will peak at over 30 litres would have an expected DMI of 19–21 kg of dry matter.

“Where there is a shortfall here, it needs to be supplemented, or you run the risk of a protein decline.”

According to Richard, butterfat will be dictated by the energy levels in the rumen. Cows on high amounts of poor-quality forage can experience butterfat depression due to the lack of rumen-degradable energy. Fibre levels will also drive milk fat, with straw being a more effective fibre than silage and silage being more effective than grass.

It is not always possible to include long, effective fibre when cows are at grass, so extra attention needs to be placed on the parlour feed by including high levels of digestible fibre.

2. Rumen health

A key factor for the occurrence of butterfat depression is an elevated intake of unsaturated fats from young, leafy grass. Unsaturated fats are toxic to rumen bacteria, and in order for them to survive, they carry out a process called ‘biohydrogenation’. This, in turn, creates by-products that, in effect, stop the mammary gland from producing butterfat, leading to butterfat depression.

“This effect can be exacerbated in the presence of a low rumen pH,” Richard continued.“Fresh, lush grass can cause a drop in rumen pH, which leads to sub-acute rumen acidosis or SARA.

“If the pH is below 6, bacteria will not work as effectively. This can harm both feed intake and digestion, leading to depressed milk production.”

Avoiding conditions that can lead to SARA and improving rumen pH are central to ensuring that the rumen is working at its best, optimising the breakdown of grazed grass and concentrate, as well as improving nutrient availability.

Research shows the correlation between pH and milk fat percentage is very important: the higher the rumen pH, the higher the milkfat percentage.

“It is possible to ‘beat the drop’ and manage and maintain butterfat in early-mid lactation by ensuring Yea-Sacc® is included in dairy cow rations at this time of the year,” Richard said.

Yea-Sacc—a live yeast from Alltech — is proven in Irish grass-based systems to maintain rumen stability, increase efficiency and help cows avoid the wide variations in rumen pH that can interfere with fibre digestion and feed intake.

It works by removing air/oxygen from the rumen and increasing the presence of fibre-digesting bacteria. This helps reduce acidity in the rumen and increase the pH.

This is all about supporting rumen health, performance and efficiency, helping to optimise feed and milk production.

Research has shown that Yea-Sacc will act to increase milk production by 1.7 litres per day, improve feed conversion efficiency by 6% and help reduce the number of days open.

3. Grassland management

The focus of any grassland management programme is to grow and utilise as much grass as possible throughout the grazing season. Covers of 1,500kg DM/ha (8–9cm) should be the target on the majority of farms.

The first objective is to correctly graze out paddocks in the first round. This will result in higher quality, lush grass growing throughout the season.

Grazing these covers down to 4–5cm will promote quality further into the year. Such an approach, however, will increase the oil and reduce the fibre content of the grass.

While this promotes good milk and protein yields, it needs to be managed from a butterfat point of view and having a healthy rumen to deal with this is key.

If supplement is required, and this will be dictated by milk yield and requirements, farmers should target a daily intake of 16kg of grass DM into their cows.

High yield, weather, grass availability and stocking rate will determine whether extra supplement or a forage-based buffer is required.

4. Genetics

While addressing a drop in milk solids in early lactation, farmers need to consider a holistic approach around balancing nutrition to ensure good rumen health and monitoring the cow’s physiological state.

Longer-term benefits can be achieved by examining the genetics of the herd and reviewing the breeding policies that are followed accordingly.

For more information on the Beat the Drop campaign, visit: or call the ‘MILK SOLIDS HELPLINE’ on 00353 59 910 1320 for information on how you can BEAT THE DROP.