Editor’s note: This article was written for the William H. Miner Agricultural Research Institute Farm Report by Sarah Boucher a post-doc researcher at the Miner Institute in Chazy, N.Y.

On many dairy farms, a single total mixed ration (TMR) is fed to the milking herd after the cows leave the fresh pen or even after calving. There is a lot of information about providing a separate TMR to fresh cows, but what about providing a separate TMR to cows in early to peak lactation versus cows in later lactation? Two of the primary reasons to feed these two groups different TMRs are to prevent over-conditioning of later lactation animals and manage feed costs. Recently Dr. Michael Allen from Michigan State University presented information about “Grouping to Increase Milk Yield and Decrease Feed Costs” at the Tri-State Dairy Nutrition Conference in Fort Wayne, Ind., (reference below). Some of the key points of these conference proceedings will be highlighted in this article.

The nutrient requirements of high producing cows are very different from low producing cows. If the same TMR is fed to both groups, you run the risk of feeding below the requirements of the high producers, which will limit milk and milk component production, or feeding above the requirements for the low producing group, which can lead to over-conditioning. When cows in late lactation gain excess body condition, they are at increased risk of developing metabolic and reproductive problems in the subsequent lactation. Use of rbST helps prevent over-conditioning of late lactation animals, which has allowed for relative success of feeding a one group TMR to the lactating herd. However, because many herds are not using rbST anymore, it may be time to re-evaluate grouping strategies in the milking herd.

An important benefit of utilizing grouping strategies is that feed costs can often be reduced. If grouping strategies are implemented, you can maximize forage utilization in the low producing group and decrease the need for purchased feeds. Right now, many producers are looking for ways to cut feed costs. Cutting out highly fermentable carbohydrates and good quality protein sources from the high producing cows can negatively impact milk production, which may not help the bottom line. However, grouping and maximizing forage utilization in the TMR of late lactation animals can save on feed costs without sacrificing milk production.

One argument that is often heard for maintaining a one group TMR strategy is that labor savings are realized when one TMR is fed to the milking herd, but depending on the mixer capacity, pen size, and herd size, labor costs may not increase when groups are fed different TMRs.

Some of the key points of grouping strategies highlighted by Dr. Allen are:

Benefits of grouping:

  • Optimal forage allocation
  • Increased efficiency of nutrient utilization
  • Decreased nitrogen excretion

Potential profits to be realized:

  • Increased milk and milk component yields
  • Decreased feed costs
  • Decreased culling

Herds that will benefit most are those that:

  • Do not use rbST
  • Have more variation in milk yield and age among cows

Re-evaluating the use of multiple TMRs in the lactating herd may be of benefit at this time due to high feed costs, particularly if you are no longer using rbST. However, it is important to evaluate changes in both labor and feed costs if these strategies are implemented.

Reference: Allen, M. S. 2009. Grouping to increase milk yield and decrease feed costs. In: Proceedings of the Tri-State Dairy Nutrition Conference, p. 61. Fort Wayne, IN.

Source: William H. Miner Agricultural Research Institute Farm Report