Milk Reduction Strategies Through Diet and Nutrition

Matt Lippert | Dairy & Livestock Agent | Extension Clark and Wood Counties
Liz Binversie | Agriculture Educator | Extension Brown County
Matt Akins | Dairy Specialist | UW-Madison Dept. of Animal and Dairy Sciences/Extension

Reformulation of rations can be an effective way to reduce production and lower feed costs. Care should be taken to maintain cow health. Changes made today may have impacts throughout the lactation. Maintaining production potential for early lactation and peak cows will allow for more potential to recover production when milk reduction is no longer needed. Before making diet changes, consult with your nutritionist.

Decreasing energy intake is a basic way to lower milk production. Lowering dry matter intake and decreased energy density are both ways of lowering energy intake. Increasing ration fiber levels as measured by neutral detergent fiber (NDF) is an option available for all herds. This change is expected to lower intake as well as energy density.

Replacing non-fiber carbohydrates such as starch and sugar, typically from corn and replacing with NDF from forage sources will lower energy intake. Considerations for these ration adjustments include:

  • Herd forage consumption will increase. Forage inventories must be adequate to accommodate these adjustments.
  • Type of forage substitutions can be effective as well as increasing total forage. Substituting forages that are more mature, higher in fiber, lower in digestibility, and forages previously allocated to dry cows and heifers will raise ration NDF levels. By using ration simulation, replacing 150 Relative Forage Quality (RFQ) haylage with 100 RFQ haylage, the estimated milk reduction was two pounds.
  • If forage supplies are adequate, this will lower energy, raise rumen pH, and reduce purchased feed cost.
  • Cornell University suggests adjusting fiber up to 33-35% aNDFom (replacing corn grain with 3-6 pounds of DM from forage) with an increase of 3-4 points NDF likely decreasing milk production about 2-4 pounds based on ration simulations. Replacing a larger proportion of corn grain with haylage (from a 70:30 to a 50:50 corn silage to haylage ratio) was estimated to reduce milk production by 5-9 pounds.
  • Increasing high fiber byproduct feeds instead of forage will increase purchased feed cost and may be difficult depending on byproduct availability may not have as much of an impact on production.
  • Due to greater NDF intake and rumen pH, farmers may see a positive butterfat response.

Reducing or eliminating supplemental fat in the ration. Fat is the most energy dense component of the ration and is usually more expensive per calorie than other sources. Reducing fat in the diet is a direct way to decrease energy density.

  • Not all farms feed supplemental fat so this is only an option for herds that do. Using ration simulation, if feeding one pound of supplemental fat, the estimated milk reduction was 5-6 pounds when the fat was replaced with the forage portion of the diet.
  • Reducing fat may be effective for herds also going from 3X to 2X milking as energy needs will be lower due to the milking change.
  • Evaluate ration starch levels and replace fat with forage unless starch/sugar levels are adequate with room for an increase. Replacing fat with corn could contribute to acidosis.

Evaluate herd average body condition. Body condition changes during the lactation cycle. The strategy of reducing milk production by decreasing dietary energy intake can result in lower average body condition over a long-term feeding period. This could have negative impacts on herd fertility, increased lameness, and lower production in the following lactation. Many herds have adequate condition and will not see negative impacts.

Evaluate Protein Feeding.  During times of surplus, when looking to decrease milk production, decreasing costs is beneficial if the ration remains adequate for the cows. Non-energy adjustments to the ration can also result in less production and cost. One option to consider is to eliminate “safety factor” protein supplementation:

  • As TMRs feed a varied group of cows, with different production levels and intake, most rations supply more protein than the group average requires.
  • By reducing the protein level, only a portion of the herd will lower production but purchased feed cost will be reduced. Consider current protein level, amino acid ratios, milk urea nitrogen level, and other estimates of protein and energy balance when implementing this change.
  • Feeding multiple groups with different diets and implementing protein reduction primarily on later lactation cows will keep early lactation cows ready to increase production when production constraints are relaxed.

As always, review ration additives, consider cost/head/day, and consider removing if not necessary.

  • Typically, if an additive was effective before, it will be now as well and may contribute to animal health as well as production, but it is a good strategy to review what is included and what the intended purpose is.
  • Transition and early lactation cows typically have the greatest response and most positive return for the investment in ration additives.

Table 1. Base diet used in AMTS computer modeling scenarios. Corn silage and alfalfa silage data from 2019.

Ingredient % of DM Nutrient %DM
Corn Silage 37% CP 17.1
Alfalfa Silage 16% NDF 28
Ground corn 18% Forage NDF 19.7
Corn gluten feed 10% Starch 28
Soybean meal (solvent) 8.5% NEl, Mcal/lb 0.77
Expeller soybean meal 5.5%
Vitamin/mineral mix 3%
Supplemental fat 2%
TOTAL 100%

Milk yield reduction estimates reflect metabolizable energy allowable milk using AMTS computer modeling scenarios. Special thanks to Dairyland Laboratories for 2019 forage analysis data. May not reflect actual performance. Diets scenarios were not re-balanced after changes to forage content or fat supplementation with additional adjustments needed.

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