Four Steps to a Higher Fat Test

Four Steps to a Higher Fat Test

People who write for a living like to think what they write has an impact on the people who read their material.

There are few articles written in the non-agricultural press that have had a greater impact on the dairy industry than the article that appeared in the June 23, 2014 issue of Time magazine. You probably know the article, it’s the one with the iconic swirl of butter on the cover. The title every dairy producer wants to see is on the top, just under the masthead. It reads “Eat Butter.”

Prior to that article, consumers saw fat as bad and protein as good. After that article, and subsequent research findings that supported it, the demand for butter took off. Take a look at Graph 1. Going back to 2001, the average price of protein paid through Federal Milk Marketing Order was always higher than fat. Since 2015, the average price for butter fat has always been higher than protein, and the spread has only gotten bigger. 


A high component price means it’s more important than ever for dairy producers to make sure their cows are producing as much fat as possible. It appears producers are responding. 

In November 2018, average butterfat tests of milk received in federal milk marketing orders hit 4.01%, the highest since 2001 (see Graph 2). It was the same level in December. Results from January, February and March 2019 show fat tests have been just a shade under 4.0 in each of those months. Producers are sending historical amounts of fat to processing, taking advantage of higher prices paid for butterfat.

Most of the improvement in fat tests is due to genetics and nutrition. While he national herd is still mostly Holstein, more cows from colored breeds are showing up. USDA data from 2014 shows that while less than 8% of the cowherd is Jersey, the little brown cows show up in nearly 30% of dairy operations. 

In addition, crossbreeding has become more popular as producers take advantage of heterosis, greater fertility and better feed efficiency. 

Dairy producers are also breeding for higher components. Genetic indexes, such as Net Merit $ ($NM), place an emphasis on higher component milk. So even as dairy producers add a little more color to their herds, the Holsteins are expressing more of their genetic ability to produce milk with higher amounts of butterfat. 

“We definitely do breed for the fat test,” says Mike McCulley, who milks 275 cows near Reedsville, Wis. His Holstein herd averages just over a 4.0 fat test. “We adjust matings to whatever the cow needs with fat and protein in mind. We’re targeting higher fat and protein bulls to compensate for what the cow doesn’t have.”

But what if you’re one of those herds that has a low fat test? Or what if you’ve noticed fat tests going down recently? What are your options?

First, you need to know what a healthy fat test looks like. If your herd is below breed average for butterfat test, you need to look at opportunities for improvement. Likewise, if the fat percentage of the milk shipped from your dairy has dropped by 0.2% of more, you are likely in, about to experience milk fat depression. 

Before you make any ration changes, try to determine the cause. Ask a few questions to identify the issue.

> “When did the milk fat [depression] start to happen and what was going on seven to 10 days prior to it happening?”asks Adam Lock, associate professor of dairy nutrition at Michigan State University. Milk fat depression that occurs because of diet changes usually starts at about seven to 10 days after the change occurs. If that change, or any other change on the dairy, affected the population of microbes inside the rumen, it probably had a negative effect on milk fat production. 

> Is the milk fat depression specific to one string of animals? Which cows are affected and which diets? “Higher producing cows tend to be susceptible to milk fat depression,” Lock notes.

> What season is it? “There is a seasonal rhythm of milk fat concentration so expect milk fat to be about 0.25 units lower in July that it was in January,” says Kevin Harvatine, associate professor of nutritional physiology at Penn State University.

> Is the sample a daily average? A multiday sample does not help pinpoint when the issue started, where as a one-day sample can narrow down the time.Once you have identified the problem, lay out a four-step process to getting your herd back on track.


Where do you want your fat test to be? Are you doing everything to breed cattle that are capable of reaching a higher fat test?


This will have the largest effect on alleviating milk fat depression and boosting fat production. Balancing the diet is based on properly feeding the microbes inside the rumen.

“Diet and management risk factors result in a change in rumen microbes that produce fatty acid intermediates,” Harvatine says. “This can account for up to 50% of the reason for the reduction in milk fat. This is a very common cause of reduced milk fat yield, but it is not meant to explain every change in milk fat.”

The biggest factor relating to milk fat depression, from a nutritional standpoint, is based on how fatty acids change once they hit the rumen. To understand that change, it takes a short chemistry lesson. 

The change happens when microbes inside the rumen convert the fatty acids in the feed into other fatty acids that leave the rumen for the small intestine. Which fatty acids enter the rumen and how much are converted determines the fatty acids produced. 

“We need to find out what level of fatty acids are in the diet and what sources they are coming from, either from supplements or feedstuffs,” Lock explains. “We also need to know how unsaturated the fatty acids are to determine what impact this might be having on milk fat depression.”

There are a number of feedstuffs and forages that have different fatty acid profiles that can be consumed by rumen microbes and changed into beneficial fat precursors. There are also feed additives that can either offer a specific source of fatty acids or are fed in a protected form that allows the ingredient to bypass the rumen and go straight to the small intestine. Still other additives, such as yeasts and direct-fed microbials, may be beneficial to microbial growth and create a more stable rumen environment. 

“Producers should take advantage of inexpensive rumen available fat from things like soybeans and cottonseed,” Harvatine says. “But they still have to be careful about how much unsaturated fat is in the diet. Balance unsaturated fats that are slowly available in the rumen, like cottonseed or roasted soybeans, with rapidly available fats like distillers grains.”

Balancing diets for a positive dietary cation-anion difference (DCAD) in the lactating ration can also have a positive impact on milk fat depression, and can also help prevent heat stress by supplementing additional sodium and potassium in the diet. 

“Producers should also find out if the diet is too fermentable and if they need to reduce it,” Lock says. “Also know if there is enough fiber in the diet, and enough buffer to manage rumen pH.”

McCulley noticed a bump in fat after he switched from feeding high moisture corn to dry corn. He had always been feeding a half high-moisture corn and half dry corn diet. 

“Last year we switched to an all dry corn diet and that really helped bump [our] fat test,” McCulley says. “We feel it’s more consistent. Especially in the summer, the high moisture corn would get a little off smell sometimes, so with the dry corn we don’t need to worry about that.”


Remember, when managing milk fat levels, it’s all about the rumen. Your cow needs a quiet, stable, consistent rumen environment to keep the microbes happy and productive. Here are some factors to consider when evaluating your feeding system:

Feeding frequency. Avoid slug feeding and empty bunk syndrome. Manage feeding times and coordinate with milking times to manage feeding behavior and reduce slug feeding,” Harvatine says. “Fresh feed delivery is a strong stimulus to cows. It is better to feed twice per day and deliver feeding before or between milkings to increase number of meals.”
A stickler for consistency, McCulley does all the feeding himself, and feed is always delivered at the same time every day. McCulley also makes sure he has less than a half of a skid steer bucket left over to stay at the right amount of feed delivered. 

“If it gets to be over a skid steer bucket I adjust down on the feeding rate,” McCulley says. He also pays attention to ration dry matter content, especially with haylage. His haylage is stored in bags, which means it doesn’t get mixed as well as the corn silage, which is in a larger pile. 

“In a bag [moisture] can get inconsistent because every load gets trucked in and bagged in order. It’s not like it’s getting spread out with the pile,” he says. “When you’re changing fields, that moisture can be different.” McCulley watches the weight of the haylage he’s feeding, and if it changes too much he stops and does a moisture test. 

Ration mixing. Make sure the ration is mixed properly and thoroughly, Lock says, to avoid sorting at the bunk. 
Stocking density. Ensure there is enough room at the bunk for cows to eat when they are hungry, rather than standing around waiting for a meal. In the end, consistency is key. 
“Consistency and attention to detail is very important on the farm,” McCulley says. “I don’t care what it is, if it’s feeding calves, feeding cows, watching maternity pens, whatever.” 


“Induction of and recovery from milk fat depression takes 10 to 20 days,” Harvatine says. “If you get into a problem, you should see things improving in seven to 10 days if you fix the right things.”

When the value of butterfat is high in the milk check, you don’t want to have to go through an extended period of milk fat depression. Monitor cows closely so you can identify when fat levels begin to drop, then work with your nutritionist to devise a plan to get cows back on track. 

Taylor Leach
Tue, 05/14/2019 – 10:55


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Source: Dairy Herd