New advice for feeding dairy cows from the 2023 Minnesota animal nutrition conference

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Source: University of Minnesota

The 84th annual Minnesota Nutrition Conference was held this past September in Mankato, and covered a wide range of topics from neonatal nutrition, improving protein utilization of dairy cows, and updates on forage nutrition of cattle.

Research updates from the University of Minnesota (UMN) included Isaac Salfer’s work comparing cow performance and behavior of cows fed with conventional TMR mixers versus those fed with automated feeding robots. He observed that the nutrient composition of the feed bunk is generally more consistent across the day when automated feeding robots are used, and cow activity is generally increased in herds with these feeding systems as well.

Brad Heins, UMN, focused on ongoing and upcoming research on genetic and nutritional approaches to reduce methane in dairy cows. He discussed a current project feeding seaweed to grazing animals and measuring the impact on methane emissions of cows. This presentation led to a lively discussion about the various opportunities and challenges of using feed additives to reduce methane production.

Isaac Haagen, UMN, discussed his current work on the development of genetic traits measuring the feed efficiency of pre-weaned dairy calves. He showed promising data demonstrating that the feed efficiency of calves was moderately heritable. He suggested that selecting for more feed-efficient calves could reduce feed costs early in life, and potentially select for more efficient cows.

Gail Carpenter from Iowa State University discussed nutritional strategies for cows during the transition period and heifers transitioning from the pre-weaning to the post-weaning period. Inflammation is a natural phenomenon during the transition period but minimizing “bad inflammation” is key to preventing metabolic disease. Research on treating cows with anti-inflammatory drugs after calving has shown that it improves milk production during the ensuing lactation. She also provided practical strategies for reducing stress in cows and calves including improving cleanliness, reducing pen moves and providing access to fresh, high-quality feed.

Leticia Marra Campos from Virginia Tech discussed her novel and exciting research looking at ways to use the feeding systems within milking robots to provide targeted amino acids to animals based on their specific requirements. Her research has found that including amino acids within a robot pellet can reduce feed costs and increase income.

Jeff Firkins from The Ohio State University talked about feeding iso-acids to improve microbial efficiency. Iso-acids are small organic acids that are generated during rumen fermentation. They are used as growth factors for fiber-degrading rumen bacteria and also can be used to make other required nutrients for the cow such as branched-chain amino acids. Adding iso-acids to the diet consistently improves microbial growth efficiency and fiber degradation. Under the right dietary conditions, iso-acids also have a strong positive impact on milk protein production.

Paul Kononoff from the University of Nebraska discussed the advantages of including high-quality alfalfa in lactating dairy cow diets. Data shows that when cows were allowed to choose between three different qualities of feed (low, medium and high relative feed value) they were able to differentiate and prefer higher-quality alfalfa.

Paul presented updates on the measurement of forage fragility within feeds. Forage fragility is the ability for feed particles to break down and become less buoyant within the rumen. The latest 2021 nutrient requirements for dairy cattle are beginning to consider forage fragility in their nutrition model by measuring the ADF to NDF ratio (acid detergent fiber to neutral detergent fiber). However, this is still a preliminary measure and additional research is needed.

Luis Feraretto from the University of Wisconsin focused on corn silage, especially factors affecting the fatty acid composition of forages. High concentrations of dietary polyunsaturated fatty acids can lead to reduced milk fat via diet-induced milk-fat depression. While not extremely dense in fatty acids, corn silage can have a major impact on the amount of unsaturated fatty acids in the diet because it typically makes up such a large percentage of the total diet and because the fatty acids present within corn silage are primarily polyunsaturated. Some of the factors that can increase the polyunsaturated fatty acid concentration of corn silage include increased maturity, increased storage length, higher cut height, and hybrid vs. conventional corn (conventional corn silage is higher in fatty acids than brown midrib). All of these factors should be considered within lactating cow diets.

As evidenced by the diverse and relevant topics highlighted in the dairy program, the 2023 Minnesota Nutrition Conference was a great success. We hope to see as many of you as possible at the conference next year.

Author: Isaac J. Salfer, assistant professor of dairy nutrition