Milk production in U.S. dairy herds has increased threefold in the past 60 years, from 7,000 lb. per cow per year in 1960 to 21,000 lb. today.
And, through it all, the cow has become ever more efficient, increasing production per unit of feed.
“Selecting cows for more milk has had a large impact on feed efficiency," says Mike VandeHaar, Michigan State University Department of Animal Science. “Modern cows eat more than twice as much feed as their ancestors, while the amount of feed used for cow maintenance has increased only a little. Therefore, the extra feed goes toward milk, and the cows use feed more efficiently.”
As the dairy industry moves forward, increasing feed efficiency will require a new mindset and new tools, including genomic selection factors. And researchers are working to provide just that.
VandeHaar says true feed efficiency is more than simply more milk per cow. Rather, it should be viewed as more milk solids per unit of body weight.
Although dairymen strive for maximum feed efficiency, he says, their true goal is profitable cows.
“In my view, nutritionists should not promote feed efficiency as pounds of milk per pound of feed,” he says. “With this rationale, you will be feeding diets that are high in starch and fat to animals that could eat more fiber, particularly those in late lactation. You can feed late-lactation cows diets with more digestible fiber and less starch, and they will make milk and be more profitable. Nutritionists should worry about income over feed costs, not milk to feed.”
Embrace multiple total mixed rations (TMRs).
The best way to maximize feed efficiency and profitability, given the tools available today, is to group cows into two to three TMRs by stage of lactation, VandeHaar says.
“There is no way to maximize feed efficiency with one TMR for the entire herd,” he says.
VandeHaar says research has shown that producers who feed one TMR during lactation often do so for ease.
“Smaller farms may not feel the need to mix two loads. Some large farms may not believe their employees can handle an additional TMR,” he says.
Others who utilize only one TMR during lactation may believe they will experience a drop in milk production.
“When people feed one TMR, it’s a diet targeted for cows near peak lactation,” VandeHaar says. “A diet balanced for late-lactation cows contains less starch and protein. During the switch to a late-lactation TMR, some cows may experience a drop in production, but it’s often just a temporary drop.”
However, many late-lactation diets contain too much forage fiber, he says. Reducing this forage fiber, and replacing with a highly digestible byproduct fiber, can result in just as much milk for late-lactation cows, but with less starch and protein, and less gain in body fat.
“If the diet is balanced correctly, you shouldn’t see a drop in production, and the cows should come into calving healthier,” VandeHaar says. “And you can save 50¢ to $1 per cow per day, over the high-lactation TMR.”
Genomics to come.
Through a large grant from the USDA National Institute of Food and Agriculture, a team of geneticists and nutritionists from several universities – including Michigan State, Wisconsin, Iowa State, Florida and Virginia Tech – are developing genomic tools to select for feed efficiency. They are now are working with the USDA Animal Genomics and Improvement Laboratory and the Council for Dairy Cattle Breeding to implement them.
In the near future – possibly within the next three years, VandeHaar says – dairymen will be able to select for a trait called “feed saved” or “residual feed intake,” which is basically less feed per unit of milk.
“Some cows eat less and produce the same amount of milk, even after adjusting for body weight and body condition changes,” he says. “We don’t understand why. Maybe they digest feed better or have lower maintenance requirements. But we will be able to use genomics to select for animals that require less feed per unit of milk. Eventually, this will be an important selection tool.”
“Breeding cows for less feed per unit of milk is a good goal on farms, as it’s highly correlated with profitability,” he continues. “However, when it comes to nutrition and management, we have to make sure the cows can eat as much as they want. Geneticists can try to find cows that need less feed, while still producing a lot, but nutritionists should spend more time strategizing on how to get cows to eat more.”
What should producers do until the genomic data on feed intake is available? VandeHaar says selection is still a critical tool.
“The first thing we can do: stop breeding for big cows just because you like big cows,” he says. “We don’t necessarily need to breed for small cows. But we should breed for more milk solids per unit of body weight, and it would be great to utilize bulls that are zero for body weight and body size composites. Most type traits are positively correlated to body weight, so we are naturally breeding for bigger cows.”
Utilizing selection and management tools on your operation can lead to greater feed efficiency today. And with research and data to come, genomics could help bump up your profitability in feed efficiency in the years to come.