Protect from spring butterfat depression with strategic fat supplementation

Rumen function and energy supply are paramount to protecting butterfats and fertility during spring grazing 

As dairy herds are turned out farmers must carefully balance rumen energy demands warned ruminant nutritionist for Volac Wilmar Feed Ingredients, Dr Richard Kirkland. 

He said: “Rumen function is put under a lot of pressure at turnout as cows go from having a controlled ration that is balanced in fibre and starch to a more variable forage base of grazed grass. 

“While the diet transition alone is enough to cause challenges to the rumen that can have an immediate impact on milk production, early grass growth maybe akin to rocket fuel and is expected to be rapidly fermentable.” 

High in energy, rapidly fermentable forage can cause disruptions in rumen pH and pass more quickly through the digestive system. This leads to an increased risk of acidosis and, along with the high oil load, poses a significant threat for milk fat depression, making supplement choice vital. 

Fat supplementation in buffer rations helps meet energy needs 

Variable spring grazing conditions make it harder for energy to be maximised causing a drop in fertility. In perfect grazing conditions it is possible to support 25+ litres of milk per day. Dry matter and energy intakes can be significantly reduced in wet, overcast conditions. 

“Especially for spring calvers, maximising energy intake is essential during the early part of the grazing season as cows have a greater nutrient demand to support milk production and body condition ahead of breeding within a short window of time,” said Dr Kirkland. 

During early lactation, cows cannot eat enough to meet the high energy demands of milk production and enter a state of ‘negative energy balance’, losing condition as energy from body fat stores supports the genetic drive for milk production. 

Research indicates a fall-off in conception rate of around 10% for each 0.5 unit loss in condition through this period. 

Dr Kirkland said to minimise the effect, composition of buffer feed needs to be carefully considered. High-fibre supplements like citrus pulp and soya hulls provide a better balance in the rumen and, in conjunction with a rumen-protected fat supplement, can provide the greatest response in milk fat, observed in research studies at the University of Nottingham. 

But supplementation with rapidly fermentable carbohydrates like wheat or barley may increase the risk of acidosis and make the fall in milk fat worse. 

“Rumen-protected fat supplements have around two and a half times the energy content of cereals, making them ideal to help maintain energy supply through variable spring grazing conditions without the undesirable rumen effects we see from starchy cereals through the transition from the winter diet to the spring grazing scenario,” said Dr Kirkland. 

Using strategic fat supplementation to optimise milk contracts 

Dr Kirkland said individual fatty acids impact cow performance and influence partitioning of nutrients between milk and body fat stores. So, fat supplements should be selected based on the blend of fatty acids they contain, the stage of lactation, individual farm challenges and requirements to maximise returns from specific milk contracts. 

To support both fertility and milk production Dr Kirkland advised feeding a rumen-protected fat supplement with a research-proven ratio of C16:0 (palmitic acid) and C18:1 (oleic acid) – like Mega-fat Multi to strategically influence the partitioning of nutrients between milk and body condition. 

“Fatty acids, the building blocks of fat supplements, influence the partitioning of nutrients to specific areas of cow 

performance, enabling producers to choose supplements according to milk contract requirements at particular stages in the lactation cycle,” explains Dr Kirkland. 

During the early lactation period C18:1 is a key fatty acid, increasing partitioning of energy and nutrients to improve body 

condition as well as improved development of fertilised eggs. However, given the challenges of early spring grass, products containing higher levels of C16:0 can be 

considered as effective ingredients to increase milk fat production. 

“Careful choice of supplements is essential at grazing to provide those vital megajoules of energy in a form that stimulates the rumen and milk fat production,” added Dr Kirkland. 

“By selecting a rumen protected fat supplement such as Mega-Fat Multi, farmers can support both fertility and milk 

production performance while helping ensure energy demands are being met in a safe way.”