Feeding to improve butter fats this summer

Increasing milk quality, specifically butterfats is about the only option open to dairy farmers to positively influence milk price in the short term. According to UFAC’s Mike Chown while it is possible to take action to boost butterfats, it will need careful rationing and close attention to detail especially as cows go out to grass when BF typically drops.

There is no doubt that raising butterfats will increase prices under the terms of many constituent priced contracts. Bonuses of 1.5-2.7p/% depending on contract terms are quite common so the incentive is there.

With margins under pressure it is vital to stress that whatever you do in pursuit of higher prices must be economic. There is absolutely no point doing something if it doesn’t generate a margin, so make sure you know the true costs and measure the returns.

Equally you need to make sure that any short term gains don’t store up longer term problems. For example, you don’t want to boost butterfats now if the consequences are poorer body condition score and fertility later in the year when hopefully prices will be showing signs of recovery. So what are the options?

Relationship between yield and %

First and foremost it is important to remember that yield and constituent percentages are strongly correlated. In simple terms a cow produces a weight of constituents per day which is then distributed across the litres produced. So as yield increases so the constituent percentage drops because the weight of fat or protein produced is spread over more litres. To illustrate this point, table 1 shows the butterfat yield at different combinations of milk yield and percent. There is roughly the same physical fat in 25 litres at 4.1% as there is in 30 litres at 3.5%.

Table 1

If you want to produce higher quality milk you have to feed for it or one or other will suffer and this will mean increasing the energy in the diet.

Where does fat come from?

As well as ensuring the total energy is sufficient it is vital to feed the energy that will result in a higher fat yield. Butterfat actually comes from two sources:

• 50% comes indirectly from the majority of diet, from the VFAs produced by rumen fermentation
• 50% comes directly from oil in the diet

To maximise fat production you have to address both these sources. You need to make sure the basic diet is right and then ensure enough oil/fat in the diet. Provided this is achieved you will usually see both an increase in yield and in fat production.

For the basic diet you are looking at establishing and maintaining an effective rumen fermentation and maximising dry matter intake. Key to this will be such factors as;

• Feeding frequency and feed space
• Forage: concentrate ratio
• Balancing the sources of energy to ensure rumen synchrony and to reduce acidosis risk
• Avoiding sudden changes to the ration

For grazing cows it will be vital to maintain both grazing quality and quantity. Don’t leave the contribution from grazing to chance. Measure it and manage it so that cows are getting plenty of high quality grazing and clean water to maintain intakes.

Then the issue is providing sufficient fat or oil. Table 2 shows how much dietary fat needs to be supplied for different yield and fat percentage combinations.

Table 2 Dietary fat (g/cow/ day) requirements for different combinations

If you don’t provide enough oil you won’t get the fat yield and fat percentage. You also increase the risk of cow’s mobilising body fat leading to condition score loss.

The first problem is that grazing and silage are not good sources of oil. Cows eating 12kgDM grazing/day will get 360g/day of oil from forage so will need supplementation if butterfat production is to be maintained. A 30 litre cow at 3.9% fat will need additional 225g of dietary fat. So it is essential to know the oil content of supplementary feeds.

Feeding 4.5kgs/head/day of a typical compound at 5.5% oil can supply the 225g required, but it is important to question whether it supplies the correct balance of essential fatty acids for production, herd health and fertility.
TMR fed herds face a bigger potential problem as most commonly used straights such as cereals and oilseed meals are 2.5-3.5% fat so it can be hard to get the fat intakes required to support higher milk yield, butterfat levels and fertility.

The best way to ensure sufficient supplementation is to include dietary fats in the TMR. You need to ensure the product added is a highly digestible blend of essential fatty acids and C16 fats, combined with glycerol to increase energy utilisation. Fed at 300 -750g/cow/day, UFAC Buta-Cup Extra, Orbit and Omega Cream are proven to supply the essential fatty acids required to support higher butterfats and complement the rest of the diet. Being rumen –inert they help reduce the risk of acidosis and will not compromise the digestion of the rest of the diet.

By paying close attention to the total diet it should be possible for many farmers to improve milk prices and margins this summer by pursuing a strategy of improving butterfat percent. But it will be essential to monitor performance, costs and returns hawkishly to make sure that you are making a worthwhile return.

Keys to improving butterfat

• Maintain dry matter intakes
• Promote high rumen health
• Feed quality forages, whether grazed or conserved
• Ensure sufficient levels of oil in the diet
• Supply highly digestible rumen-inert oil supplements