Maintaining or Improving Milk Components

Milk prices received at the farm level continue below the production cost for most dairy farms.  While milk production remains important, of more significance is the fact that milk components sold determines the milk check.  Milk contains three major components, milk fat, commonly called butterfat, protein and other solids.  The other solids component consists mainly of lactose and minerals.  The milk check lists the price of each of those components multiplied by the pounds of each of those components supplied by the milk the farmer shipped to the processor.  As milk quality bonuses decrease or go away altogether, one strategy to improve the milk check is to focus on improving milk component yield without offsetting feed costs. 

Generally milk fat and milk protein are higher priced components and lately milk fat has been a larger contributor to milk checks than milk protein.  For example, the USDA announced component prices (per pound) for March 2018 are $2.4273 for butterfat, $1.8066 for protein, $0.5232 for nonfat solids and $0.0556 for other solids.  Given the current price of butterfat vs. protein, dairy producers may choose to focus on improving milk fat yield.  Milk fat synthesis is a complex process beyond the scope of this column; however, a simplified explanation for part of the process begins within the rumen of the cow, where products of digestion by the microbes include volatile fatty acids, commonly designated as VFA’s.  Those VFA’s are acetate, propionate and butyrate.  The proportion of each is dependent upon the feedstuff supplied to the rumen microbes.  Concentrates, think grains, yield a high propionate percentage.  Propionate is used to manufacture glucose, necessary to produce milk volume.  Digestion of high fiber feeds, think forages, yield a higher percentage of acetate and butyrate.  These two VFA’s and in particular acetate, are used in the udder to form about 50% of the fat in milk.  Diet is highly correlated with milk fat concentration or percentage.  Changes in diet can directly affect milk fat percentage.  For example, a diet change could alter milk fat percentage as much as one percentage point within 7 to 14 days. (https://extension.psu.edu/milk-components-understanding-milk-fat-and-protein-variation-in-your-dairy-herd)

I recently attended the 2018 Tri-State Dairy Nutrition Conference in Fort Wayne IN.  One of the presentations I listened to was entitled “Feeding the Rumen to Maximize Milk Components” by Benjamin Wenner with CSA Animal Nutrition.  Wenner concentrated on practices that could improve milk fat yield and his approach was to focus on high quality feed ingredients combined with attention to detail in feeding practices rather than reliance upon a lot of feed additives.  One of his earliest statements noted that improved fiber digestibility is a target to increase milk fat yield.  Quoting from the article that supported his presentation, Wenner says “Fiber digestibility is not only important in limiting milk fat depression risk, but improved fiber digestibility translates well to greater milk fat concentration and improved overall diet fermentability provides an additional energy boost that can help improve milk fat yield.”

Another of Wenner’s recommendations included an emphasis on feed management that contributed to rumen health and stability, with the goal of maximizing digestibility.  Specifically, attention to detail with regard to the accuracy and efficacy of ration delivery to the herd or production group has the potential to return dividends.  Producers or farm managers should evaluate the timing of TMR preparation, the consistency of the ration delivered, the degree of TMR sorting, the frequency and timing of feed pushups, as well as availability of feed bunk space. 

One of the goals of feed management is to ensure that cows do not slug feed.  Slug feeding is likely to occur when cows have restricted access to feed and/or feed easily sorted.  In these circumstances, cows eat infrequent, large meals and/or higher percentages of grain compared to a non-sorted ration.  The result is instability in the rumen, low rumen pH, and possibly rumen acidosis, which can lead to milk fat depression.  Ideally, cows should eat 10 or more smaller meals throughout the day, so they need to have the TMR available around 20 hours per day.  Part of this availability is fresh feed delivery, and part is room at the bunk when the cow wants to eat.  Feed push up can stimulate intake and there is research to suggest that feed push up in the first couple of hours post-feeding produces the most benefit.

In summary, focus on management practices that will keep the rumen healthy and functioning.  Put effort into producing, storing and feeding high quality, high digestibility forages.  Evaluate TMR mixing and feed delivery, including feed push up.  Ensure each cow has enough bunk space.  Attention to detail does not require costly expenditures, but can help to improve milk component yield.  Finally, with regard to feed additives, I’ll quote another section of the Wenner paper “If you think that you have milk fat on the table and want to pursue changes to the diet beyond management considerations, methionine in the rumen to stimulate fiber digestion might be a good place to look.”