When my son was young, it was recommended that we supplement with formula for a while, and entering the world of formula options, compositions, and consequences made my very tired mom brain hurt. Most of all, it reminded me of the wide array of opinions that exist when deciding between types of milk replacer to feed dairy calves.
On our operation, we have always selected to feed whole milk to calves, but I have heard many times the discussions that can get started when the topic of milk replacer composition comes up on a dairy or between salesmen.
Recently, Virginia Tech’s Shannon Chick explored some of the research surrounding milk replacer composition and its effects on gastrointestinal health of calves in a recent Virginia Dairy Pipeline newsletter.
Specifically, Chick reviewed several studies that dove into fats in milk replacer starting with the ratio of omega-6 (n-6) and omega-3 (n-3) fatty acids. “In some milk replacers, the ratio is 35 to 1, while in whole milk, the ratio is 5 to 1,” she explained. “These fatty acids are precursors of immune molecules that can cause an inflammatory response.”
In a study cited by Chick from a research group in the Netherlands, calves were either given milk replacer with a ratio of 40.6 to 1 or 6.5 to 1.
“The researchers found that decreasing the ratio of n-6 to n-3 may have increased tight junction function in the jejunum and ileum of the calves as the n-3 content found in those tissues was increased for the experimental group,” Chick detailed. “However, gastrointestinal permeability was mainly unchanged.”
Where’s the fat sourced?
“Use of alternative sources for fat in milk replacer can cause problems as different fat sources have varying structures in comparison to whole milk fats,” Chick shared.
Chick reviewed another study done in the Netherlands that dove into these sources of fat and their impacts. Milk replacer composed of animal fats was compared to a milk replacer sourced with vegetable fats and a milk replacer featuring both animal and vegetable-sourced fats.
The researchers concluded that composition of the milk replacer had no impact on growth, milk replacer intake, total-tract digestibility, or gastrointestinal permeability. They did note a difference in abomasal emptying with the vegetable-sourced fats.
While none of these studies conclusively suggest what milk replacers are best for calves, they indicate some of the important topics that should surround conversations about feeding milk on the farms. Just like the formula aisle in the grocery store, there are more than enough options to find the one that works best on your farm.
The author is a dairy farmer in Kansas and a former associate editor at Hoard’s Dairyman. Raised on a 150-cow dairy near Valley Center, Kansas, Maggie graduated from Kansas State University with degrees in agricultural communications and animal sciences.