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Fine-tuning dry cow Goldilocks diets

Michael Hutjens for Progressive Dairy Published on 19 July 2020
Goldilocks diets

The Goldilocks dry cow diet was developed by the University of Illinois under the leadership of Dr. Jim Drackley and his research team.

The initial term was based on the children’s book Goldilocks and The Three Bears as it related to Goldilocks making choices. In your dry cow feeding program, balancing nutrient intake for the pregnant cow, the unborn calf and colostrum synthesis is key to transition cow program success, milk production in early lactation and fertility. Table 1 compares an example of a Goldilocks dry cow ration feed ingredients to a traditional higher-energy dry cow ration.

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Goldilocks and traditional dry cow ration

Table 2 lists the suggested nutrient density of the Goldilocks dry cow ration.

Goldilocks nutrient recommendations

Modify both tables to meet your feed inventory status, feeding system, dry cow responses and cow environment. Several Goldilocks-like decisions are listed below:

Goldilocks decision 1

Initially, the Goldilocks dry ration was defined as not too high in energy, not too low in energy, but just at the right level of energy. Another term was low-energy dry cow rations (0.59 to 0.61 megacalorie of energy per pound of ration dry matter). A key factor is the measured dry matter intake (DMI) of the dry cows, as energy intake is the density or concentration of the nutrient times DMI.

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A low-energy ration could include low dry matter feed intake (less than 1.5% of bodyweight), low energy level of the ration (under 0.55 Mcal – megacalories of net energy lactation per pound DMI), reduced ration digestibility or low calculated energy (under 14 Mcal per cow per day). A high-energy dry cow diet could be caused with DMI (over 2.25 percent of cow’s bodyweight) or a ration with a calculated energy density of over 0.65 Mcal per pound of dry matter.

Goldilocks recommendation: Target 16 to 18 Mcal energy density of 0.59 to 0.61 Mcal per pound of dry matter, and 28 to 30 pounds of dry matter for mature cows and 24 to 26 pounds of dry matter for springing heifers. The feeding environment (such as cold weather) and walking distances can change target levels of energy.

Goldilocks decision 2

Physical form must be correct. Dairy farmers can pre-process straw to achieve desirable straw particle length. Depending on the TMR mixer, achieving optimal and repeatable desired length with other feed ingredients can be problematic when done on a daily basis. If the straw in the dry cow ration is too long, cows may sort against the straw as it less palatable, leading to rations that are not balanced or forcing some cows to eat low-energy diet that is higher in straw content and lower nutrients (see Goldilocks Table 2). If the straw is processed too short, the effective straw fiber may be less reduced and change the rate of feed passage.

Goldilocks recommendation: Pre-process the straw resulting in one-third by weight in the top Penn State particle box with no straw particles over 1 inch in length. Another one- third should be in the second box or middle box (depending if you are using the four- or three-box unit). Less than one-third should be in the third or pan again depending on the type of Penn State unit used.

Goldilocks decision 3

One challenge with traditional dry cow rations includes dry cows getting excessively heavy or a body condition score (BCS) at or above 3.5 (1 being thin to 5 being obese), thus reducing DMI, increasing the risk of metabolic disorders or negatively impacting cow immunity. Thin dry cows (below BCS of 2.75) can reduce energy reserves in early lactation, fertility in the next lactation or impact colostrum production.

Goldilocks recommendation: Target a BCS of 2.75 to 3.25.

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Goldilocks decision 4

Meeting the amino acid requirements for the dry cow, unborn calf and colostrum synthesis is important. Unique feed ingredients in Goldilocks rations challenge rumen bacteria and rumen-undegradable protein (RUP) feed sources. If the amino acid levels are too low, it can influence protein body reserves and lower colostrum quality. If the amino acid levels are too high, feed costs will be high and there will be an excess amount of amino acids and nitrogen, requiring energy to convert excess ammonia to blood urea nitrogen.

Goldilocks recommendation: Target 1,200 to 1,300 grams of metabolizable protein for mature Holstein cows. This calculation will require the use of a rumen-modeling program. Reviewing Table 1, three sources of nitrogen are provided in the Goldilocks ration. Soybean meal is an economic source of protein and amino acids. Heat-treated soybean meal increases the amino acids from soybean RUP sources (high-quality amino acid profile). Urea is added as a source of soluble nitrogen, providing a rumen-degraded nitrogen source for rumen microbes, as straw is low in protein and soluble protein.

Field observations and comments: Several journal articles have been published providing guidelines and repeatable research results. The following points can be considered to improve results based on comments from dairy farmers and nutritionists.

  • Adding water or molasses can improve palatability of the TMR. The straw is less dusty and more pliable as it absorbs the water. Not only does molasses improve palatability, but it can also lower sorting due to the sticky nature of liquid molasses and provides a quick source of energy for rumen microbes to stimulate growth. Molasses can also improve fiber digestion that is high in Goldilocks rations.

  • Initial research suggested keeping dry cows on the Goldilocks ration until calving. Field nutritionists report improved feed intake after calving and higher early lactation performance by adding extra energy and metabolizable protein (MP) during the last three weeks before calving. The risk of increasing the BCS is minimal as the unborn calf is requiring more nutrients along with colostrum synthesis coupled. This approach reflects a two dry cow group system, allowing for added micronutrients (such as higher levels of vitamin E) and feed additives (such as rumen-protected choline and anionic product).

  • Adding 300 milligrams of monensin (Rumensin brand name) will affect rumen fermentation and improve feed conversion.

  • If dry cows are consuming too much DMI, increase the level of straw as it can limit DMI due to physical fill. If DMI is too low, adjust the straw level down.

  • Other sources of straw and lower-quality grass hay can be used instead of wheat straw that can be expensive and less available in some areas. Cornstalks would need to be chopped similar to corn silage, and no research is available indicating this can be substituted.

  • Corn silage should be kernel processed to ensure available starch in the rumen as an energy source for rumen microbes.

  • Do not limit the amount of TMR offered by providing adequate amounts. If dry cows sort the ration, less aggressive cows are forced to consume the sorted ration lower in nutrient content. Monitor feed sorting using the Penn State box and compare results to the original TMR fed.

  • Do not overcrowd the feedbunk, influencing intake and sorting. Allow 30 inches of bunk space per pregnant cow.

  • Continue to use organic trace minerals (selenium, chromium, zinc and copper).

  • Evaluate DCAD (dietary cation-anion difference) and add anionic product to achieve the desired level. Adjust the calcium level depending if a partial or total acidification program is used.  end mark

ILLUSTRATION: Illustration by Corey Lewis.

Michael Hutjens
  • Michael Hutjens

  • Professor of Animal Sciences Emeritus
  • University of Illinois – Urbana

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