Assessing the big picture, Hutjens said he prioritizes pounds of milkfat and protein because at least 80% of U.S. dairy producers are paid according to these benchmarks, and the numbers can be boosted via genetics, feeding, and management processes. In addition, components can be used as a metric for herd health.
Breaking down the sources of milkfat, Hutjens reiterated the conventional knowledge regarding the ratio of 50-50: Half the fat comes from volatile fatty acids (VFA) via de novo synthesis in the mammary gland, and the other half from blood lipids via dietary fat, body fat mobilization, and liver and microbial synthesis. Hutjens informed viewers that tools are now available to analyze the fatty acid composition of milk and diagnose potential issues in the more granular breakdown of percentages, pointing to recent research guidelines that show about 25% to 30% of the fatty acids are ideally de novo; 40% to 45% preformed; and the remaining are mixed at about a 50-50 ratio.
Hutjens also explored cow management factors that could specifically affect de novo synthesis such as reduced feedbunk space and higher stall stocking density. Both have been correlated with lower de novo fatty acids and subsequent lower fat and protein test results.
Non-nutritional and nutritional factors were assessed during the webinar; the former include genetics, season, stage of lactation and level of production, as well as parity. Regarding nutritional factors, Hutjens honed in on high-oleic soybeans and their emerging role in milk production. These rumen-friendly strains differ in fatty-acid composition, coming in at 75% oleic and 7% linoleic, a stark contrast to conventional soybeans with their 23% oleic and 54% linoleic acids. He recommended feeding the high-oleic soybeans roasted, because the treatment supports higher levels of amino acids, but noted that they still offer benefits when fed raw.
Another recent shift noted by Hutjens is within distillers grains and their oil content. “It is really changing. Five or six years ago, we’d see distillers grains running 12% to 14% oil, but now these companies have discovered they can extract this oil and make biodiesel out of it. They don’t take it all, but you want to know what level oil you have in your distillers grains to complement your corn and corn silage levels plus any oil seeds you’re feeding,” he said.
The webinar’s takeaways revolved around the continuing need for producers to review their existing records and keep careful track of their herds going forward, using all available metrics when evaluating milk component yield: breed average versus your own herd; both the raw numbers and the ratio of milk protein to milkfat; feed efficiency; and milk urea nitrogen (MUN) values.
“Look at your records to see if there are opportunities,” Hutjens advised, noting that the 7-pound milkfat and protein goal looks more achievable all the time. He cited a recent report of a Holstein herd that, through careful management, achieved a whopping average of 8.9 pounds of milkfat and protein.
To learn more, watch the May Hoard’s Dairyman webinar, “Feeding for 7 pounds of milkfat and protein.”
