You can’t spend much time in the world of dairy social media without knowing that butterfat prices are really high. This seems like a good time since butterfat tends to increase in the fall anyway. But how can we further increase this seasonal increase and put a few more dollars in your pocket? We don’t always have the opportunity to enhance a natural tendency to make it even more impactful. It seems that we are generally working at cross purposes. This time, nature is not against us. Good!
A second-year dairy science student or any producer who spends time reading dairy magazines could probably make a quick list of low-hanging fruits to maximize milk fat. These tactics include buffer feeding, increasing the percentage of roughage in the diet, monitoring starch levels, and much more. However, what are the more nuanced approaches that can help us reach even higher levels and make the initial steps even more effective? Let’s discuss some of them.
Take a look at fiber and starch
First, we shouldn’t just look at forage percentage and starch content. Although these two phenomena tend to have an inverse relationship, this is not always the case. If the forage we are talking about is corn silage, it is really only about 50% forage. So a 60% forage ration can still be a problem producing good fat if you have the blessing of a 40% starch corn silage to feed. Instead of thinking about the percentage of forage in the feed or the ratio of forage to concentrate, we can focus on a few other nutrients. I like to think of uNDF240 as a minimum requirement to be sure there is enough structure in the diet to keep the rumen in good condition. Having too little of these indigestible fibers can lead to high intakes, poor feed conversions, and disappointing milk fat results. Think of this fiber as “rebar for the rumen.”
The next type of fiber is what produces the fat we need. This fiber is fermented in the rumen to create the building blocks that actually become fat. So we need as many of these building blocks as possible. The nutrients in your forage analysis that attempt to describe this fiber are the different neutral detergent fiber (NDF) digestibility times. This can be NDFd12, NDFd24 or NDFd30. Other times can also be estimated.
This nutrient is important not only in forage analysis but also in diet formulation. These digestible fibers do not need to come from forage sources. They can come from by-products like soy hulls, almond hulls or corn gluten. There is no excuse for a ration not to contain an adequate intake of this type of fiber. If you haven’t grown it or purchased it as hay or silage, you can still get it from various byproducts. Each nutritional model has a term for them, and meeting fat needs is essential. Diets high in starch may be at risk of being inadequate in this important nutrient, so be sure to keep starch in check.
Starch is tricky in this conversation because it plays a key role in overall energy supply for milk, maintenance and reproduction. If we increase starch levels when feeding for high milk production, but also do a good job of ensuring cows are well supplied with real forage, highly digestible fiber can be eliminated. Moderating starch a bit to make room for some highly digestible fiber can still support high levels of milk production but not harm milk fat synthesis. Monitoring the consistency of the manure can be a useful guide on this subject. Remember that sugars in the rumen act in the same way as starch.
An example of diet manipulation might explain this better. Let’s say you have an aggressive, high-starch ration that produces good milk, but the milk fat results are somewhat disappointing. If you have a diet that works well with the Penn State particle separator and the manure is perfect, what would be a good ration response to low fat? If you decide the problem is high starch, in this situation, depending on the manure and shaker, adding hay or straw may not be the best answer. This ration does not appear to require more roughage, but rather less starch and more digestible fiber. Simply moving corn kernels to soy hulls could be a solution. The highly digestible fiber in the hulls will generate the building blocks needed to produce more fat.
Thoughts on Fat
The second topic is also related to starch. However, the focus here is not on fiber, roughage, starch or sugar, but on the balance of fatty acids. It is well known that a diet rich in vegetable fats can reduce milk fat synthesis. The details here are quite complicated and may require you to pull out your college biochemistry textbook. Suffice it to say that this type of vegetable oil poses a problem for the rumen and has a significant negative impact on the fermentation process that creates the building blocks of fat. The jargon here is a little confusing, and it seems like these terms are used interchangeably to keep everyone a little confused. So if you hear things like 18:2 fatty acids, linoleic acid, unsaturated fats, or just vegetable fats, you know they pretty much describe the same thing. These fats pose a problem in the rumen. The data suggest that there is a linear relationship between increasing these fats and reducing milk fat percentage and yield. This science is unambiguous. In other words, you can put it in the bank, especially with current butterfat values.
The immediate consideration for this particular risk concerns distillers grains. However, there are several other common food ingredients that contain almost the same levels of problematic fats found in distilleries. It seems that dry distillers tend to reduce their fat content, which is a good thing. I see levels between 7% and 8% instead of the 10% previously expected. Wet stills can be even higher, and because of this variability, laboratory testing must be performed on these products. While we’re focusing on distillers, ingredients like brewers grains, hominy, and even some bypassed soy flour products are almost as high in fat as distillers. This fact may not be obvious, as not all unsaturated fats behave the same way in the rumen, but care should be taken in all cases.
The third topic is also linked to the presence of fats in the diet. While 18:2 fatty acids can harm fat content, other fats high in palmitic acid (16:0) can actually improve fat content. Increasing the 16:0 fatty acid content in the diet will increase the milk fat percentage and yield. Remember, however, that the carbons contained in different fats can only be used once. If you are currently feeding a traditional calcium salt containing good levels of 16:0 and switch to a high palm source (16:0), you may gain fat and lose support for your body condition. A calcium salt contains a combination of fatty acids that can support milk, body condition and fat. Taking care to maintain fatty acids for milk and body weight while adding 16:0 for milk fat support will be the best of both worlds. There are several strategies with branded products and even pure tallow to better target the fatty acid balance that matches the particular set of cows and season of year.
By combining these three topics to create a well-balanced ration, we can use milk fatty acid analysis to see how we are doing. This process is often called de novo analysis. This is a good name since the main objective here is to increase de novo fatty acids which have as their source the digestible fibers mentioned above. Remember that digestible forages or by-products like soy hulls make up your fat. The analysis of milk fatty acids, pen by pen, constitutes the reference in terms of optimal use of this emerging tool. Tank numbers can be helpful, but because cows at different stages of lactation have some differences based primarily on weight loss or gain, interpretations can be tricky. Nonetheless, suffice to say that if you have a very productive herd, the higher the de novo fatty acids, the more successful your cows are at converting forage and by-product fiber into butter. Stay tuned for emerging ideas on how to better utilize these milk fatty acid results. Some dairy cooperatives now report these values on each load of milk, as do fat, protein and somatic cells. We can feed cows better by paying greater attention to these values.
One final note is things on the dairy as opposed to inside the fodder lab and my computer. Factors such as cow comfort, feed trough space, feed pumps, number of meals per day, tracking shaker results, cow cooling, hoof health, crowding, etc. . all have an impact on de novo fatty acid synthesis. Almost any best management practice for properly caring for cows will improve de novo fatty acids, your butterfat percentage, and your milk income.
