[Skip to Content]

Dairy Cattle
Illinois Livestock Trail
NOTICE - This information has been archived and may contain outdated content.
Identifying Limiting Nutritional Constraints to Profitability
by Michael F. Hutjens

Take Home Messages

  • Dairy managers should partition their feed costs to determine if all areas are price competitive compared to herds in their area at comparable production.
  • Dry matter intake will be the key management factor to maximizing profitability including the role of forage quality, factors that limits consumption, and dry matter intake management factors.
  • Purchased feeds should be portioned correctly to maximize profit responses based on milk yield and forage quality.
  • Service is critical to profitability and must be evaluated.


Profitability can be defined as the difference between income minus expenses. Income over feed costs focuses on milk yield (income) and feed costs (expenses). Maximum milk yield is not always most profitable, but nutrient costs for maintenance are the same if cows produce 20 or 40 kg of milk. Generally, higher producing cows will increase profits, but at a diminishing rate. Partitioning feed costs is one approach to evaluate feed component costs (Table 1). Dairy managers should compare their partitioned feed costs to herds in their area and at similar levels of milk product. Additional feeding comparisons are listed below.

  • Feed cost per kg of D.M. $0.13
  • Feed cost per 45 kg of milk (milk cows only) $4.50
  • Feed cost per 45 kg of milk (including dry cows) $4.80
  • Feed cost per 45 kg of milk (including heifers) $5.80

This paper will discuss areas which are important in identifying limiting feeding factors to profitability.

Optimizing dry matter intake

Dry matter intake is "the key factor" in profitable feeding programs. Energy is the first limiting nutrient in most dairy rations. Two practical approaches to increasing energy intake are available to dairy managers and nutritionists.

  • Increase dry matter intake through feeding management, blending of ration ingredients (TMR), forage quality, nutrient balance, and optimum ration moisture.
  • Increase energy concentration per unit of dry matter intake by using higher quality forage, feeding more grain, lowering fiber levels, and adding fat or oils to the ration.

Dry matter intake guidelines are outline below which illustrate factors that impact intake and management.

  1. Most rations formulation programs base dry matter intake on milk yield and body weight (Table 2). Producers and nutritionist must refine and adjust these values based on farm situations.
  2. Dry matter intake (DMI) is lower in early lactation (Table 3). Transition dry cow rations can improve DMI postpartum by increasing rumen papilla surface area and physically expanding rumen area, and minimizing metabolic disorders such as acidosis and displaced abomasum.
  3. For each additional kg of ration DMI consumed, milk yield can increase 2 to 2.5 kg of additional milk depending on fat test and ration energy concentration.
  4. Peak dry matter intake occurs 4 to 6 weeks after peak milk or 8 to 12 weeks postpartum. Feeding TMR can shorten this lag period and encourage higher DMI.
  5. After injecting BST, dry matter intake lag milk response by 3 to 5 weeks causing cows to mobilize body weight.
  6. Feeding high levels of fat (over 5 percent total fat) after calving may reduce DMI because of high levels of NEFA (non-esterified fatty acids) mobilized from body fat reserves cause the cow to reduce lipid intake.
  7. Equations to predict pounds of dry matter intake are listed below.
  8. Cow consume 1.2 percent of the body weight as total NDF or 0.9 percent of body weight as forage NDF. For example, 600 kg cow times .012 total NDF equals 7.2 NDF intake (forage and grain). Forage intake for a 600 kg cow would be 5.4 kg (600 kg X .009).
    • Milk cows: (.018 X body weight in kg) + (kg 4% FCM X .305)
    • Example: (.018 X 600 kg) + (30 kg X .305) = 10.8 + 9.2 = 20 kg
    • Dry cows (far off): .018 X body weight in kg
    • Example: .018 X 650 kg = 11.7 kg
    • Dry cow (close up): Dry cow DMI in kg x .8
    • Example: 11.7 (above) X .8 = 9.4 kg

According to Wisconsin researchers, three factors stop cows from eating and must be managed to optimize DMI listed in Tables 2 and 3.

  • Physical fill factor which limits the cow from eating more dry matter. High levels of fiber, feed with high fill factors, slower rates of digesta flow, and long fiber sources can cause the cow to stop eating. Review ADF, NDF, lignin, and functional NDF values to evaluate if a fill factor limitation exists.
  • Elevated blood metabolites can "signal" the brain satiety center to stop eating. Chemical signals could include blood ammonia or other nitrogen compounds, circulating fat or non-esterified fatty acids, blood pH, or volatile fatty acid profiles absorbed from the rumen.
  • The environment and bunk management can cause the cow to stop eating which are independent of ration characteristics. Examples of factor three include empty bunk syndrome, moldy feed, secondary bunk fermentation, poor cow comfort, leg problems that limit cow movement, heat and cold stress, and bunk design.

When rations exceed 50 percent moisture, dry matter intake can decline. This effect applies to fermented feeds, not pasture or green chop. Cornell workers suggest a decline .02 percentage units DMI as a percent of body weight per one percentage unit increase in ration moisture. A 1400 pound cow fed a ration 10 units wetter may consume 2.8 pounds less DMI due to moisture. Israeli researchers in three experiments reported DMI was 6 to 9 percent higher with drier rations (38% DM) compared to wetter rations (53% DM). Adding a dry ingredient such as chopped hay, dry corn, beet pulp, or a buffer can increase DMI. Maryland workers reported adding buffer to corn silage prior to feed raise silage pH and DMI with an ideal ration pH of 5.5. Moisture content per se is not the main effect, but is related to fermented products produced during the ensiling process (pH, soluble nitrogen products, or VFA); intracellular water low in pH; or a localized environment low in pH which may cause fiber digesting bacteria not to attach and digest forage fiber. Rations can be too dry which can lower feed intake because feeds are dusty, fines can separate, cows prefer acidic feeds, palatability is reduced, or bunk life is shortened. Optimum ration DM appears to be 55 to 65% DM. Cows appear to be able to eat 50 kg of wet feed a day (with milk yields of 40 kg of milk).

Israeli workers proposed grouping cows receiving TMR based on DMI, days in lactation, and milk yield potential. In the initial 45 days postpartum, cows are challenged to reach true potential by consuming the high group TMR. Mature cows over 38 kg remain in the high group until they dry off or became fat. Mature cow below 38 kg were assigned to a lower quality and cheaper TMR and remain there until they dry off. Cows are not shifted after 45 days because dry matter intake was significantly reduced which reduced milk yield 2 to 4 kg a day. Differences in DMI (4 to 5 kg per cow per day), energy concentration (1.65 vs 1.76 Mcal per kg of DM), and ration costs result in economic responses.

Forage quality has a major impact on milk performance and feed intake. An ideal forage maturity should support maximum intake, optimum nutrient yield per acre, maintain forage crop stand, and minimize losses. Missouri workers illustrate the relationship of forage source and maturity to milk yield (Table 4). Improved palatability stimulates intake. Wisconsin workers proposed NDF content of forage can be used to predict forage dry matter intake (Table 5). Additional amounts of grain can not overcome lower quality forage. Low quality forages results in lower nutrient content per unit of dry matter, lower digestibility of the dry matter, and lower dry matter intake.

The following management factors can optimize DMI in the field.

  1. Forage quality that exceeds 1.32 Mcal of NE per kg of DM
  2. Ration ADF levels of 18 to 20%
  3. Ration NDF levels of 28 to 33%
  4. Effective NDF levels of 20 to 22%
  5. Fermentable carbohydrate levels of 36 to 38%
  6. Feeding of TMR
  7. Excellent dry cow rations (far off and close phases)
  8. Ration dry matter content of 55 to 65 percent
  9. True feed weigh backs of 2 to 4%
  10. DMI that meet or exceed NRC guidelines

Positioning Purchased Feeds

Purchased feed represent significant out of pocket feed costs and for lactating dairy cows including protein supplements, minerals, vitamins, fat, by-product feeds, additives, and excellent quality hay. These feeds can add up to for $1.73 per cow per day in Illinois.

  • Protein supplements = .44
  • Purchased hay = .30
  • By-product feeds = .40
  • Minerals = .11
  • Vitamins = .03
  • Fat = .33
  • Additives = .12

Purchased feeds also include charges for service (forage testing, ration balancing, consulting, and feed quality monitoring). Common questions raised by dairy farmers are listed.

  • What should my purchased feed cost be?
  • When should I purchase feeds?
  • How can I position purchased feeds?
  • How much does service cost?

Dairy producers may not purchase enough, excess levels, or the incorrect types of feeds to provide balanced and economical rations. Purchased feeds for lactating dairy cows are affected by two factors: forage quality and level of milk production (Table 6). If forage quality is low, supplemental energy and protein will be needed.

Feed additives can raise feed costs by 2" to 60" per cow per day. Table 7 lists several feed additives and strategies for use. Dairy farmers and nutritionist must correctly position feed additives to economically justify their use. Benefit to cost ratios can vary from 10:1 (anionic salts), 8:1 (ionophores and zinc methionine) to 4:1 (buffers and yeast) to 3:1 (niacin). A survey of high producing US herds in 1991 and 1983 illustrate additive use and trends.

  1991 1993
  % %
Buffer 75 70
Niacin 38 16
Yeast 51 17
Zinc Methinine 48 NA
Magnesium oxide 66 NA

Additive inclusion should be based on its role in the ration, economic response, research support; and ability to measure and evaluate on the individual farm.

Service charges and strategies

Time has value when farmers receive ration formulating and consulting from a private consultant, feed company, veterinarian, or extension personnel. A value of 10? per cow per day was used. This charge results in $3.00 per cow per month or $180 per month (for a 60 cow herd). Several methods can be used to collect this cost.

  • 1/2 day of time which results in $45 per hour charge
  • Add 1" per kg to 10 kg of pelleted complete grain mix fed per cow per day which raises grain price $10 per ton
  • Add 5" per kg to 2 kg of protein supplement fed per cow per day which raise the protein supplement price $50 per ton
  • Add $0.33 per kg to .3 kg of mineral/vitamin supplement which raises the mineral mix $330 per ton

There is no "free" time or service. Mathematics become more interesting if you calculate 150 cow herd size, $.10 per day, and services are included such as (forage testing, computer time, educational meetings, mileage and expenses incurred traveling to the farm, and expected time committed ie 1/2 day per month, phone calls at night, and response to emergencies). An effective service representative could increase milk yield 2 kg per cow (worth $.36 per day) and/or lower feed costs $.20 per day at a cost of $.10 per day (4 to 1 benefit to cost ratio).


Baile, C.A. et al. J. Dairy Sci. 64:915

Chase, L.E. (1979). Cornell Nutr. Conf. Proc. pp. 52.

Erdman, R.A. (1988). J. Dairy Sci. 71:3246.

Hutjens, M.F. et al. (1991). Four State Dairy Sem. Proc. p.1.

Kroll, O. et al. (1986). Res. Dev. in Ag. 3:1:47

Mertens, D.R. (1987). J. Anim. Sci. 64:1548.

Miller, T.K. et al. (1990). J. Dairy Sci. 73:2453

Nat. Res. Council Comm. (1989). NRC of Dairy Cattle. Ed. 6. Nat.

Acad. Sci. Washington, D.C.

Shaver, R.D. (1994). West. Can. Dairy Sem. 6:8.

Spain, J. (1994). Farmland Ind. Proc. Kansas City, MO

Table 1. Partitioning total feed costs per cow per (Illinois data at 32 kg of milk per day)

Ration Component Cost/Cow/Day ($)
Forage (11.8 kg D.M.) $1.04
Grain (9.1 kg D.M.) $1.00
Protein Supplement (2 kg) $.59
Mineral/vitamins $.30
Additives $.12
Total Cost $3.05
Cost/KG D.M. $0.13
Cost/45 Kg of milk $4.33

Table 2. Dry matter intake per day based on milk yield and body weight (NRC, 1989).

Milk Yield Live weight (kg)
(kg 4%FCM) 500 600 700 800
  --------------% B.W.----------------
20 3.2 209 2.6 2.4
30 3.9 3.5 3.2 2.9
40 4.6 4.0 3.6 3.3
50 5.4 4.7 4.1 3.7
60 --- 5.4 4.8 4.3

Table 3. Dry matter intake in early lactation based on lactation number and weeks in milk (Shaver, 1994).

Week Postpartum Primiparous Cows Multiparous Cows
1 14.1 16.5
2 15.9 19.0
3 17.3 21.1
4 18.2 22.7
5 18.9 23.9

Table 4. Influence of forage source and maturity on milk production (Spain, 1994).

  Prebloom Alfalfa Midbloom Alfalfa Fullbloom Alfalfa Brome Grass
Milk Yield (kg) 38.0 32.7 32.1 29.9
D.M. Intake (kg) 23.2 20.2 20.0 17.9
D.M. Intake (% BW) 4.03 3.49 3.43 3.08

Table 5. Influence of NDF content on predicted forage dry matter intake (Spain, 1994).

Forage Quality % NDF DMI (% BW)
Excellent 38 3.16
Above Average 42 2.86
Average 46 2.61
Below Average 50 2.40
Poor 54 2.22

Table 6. Illinois purchased feed cost for cows at different levels of milk yield and forage quality indexes (Hutjens et al, 1991).

Milk Production Feed Forage Crude Protein

Year Peak Daily 12 14 16 18 20

-------kg-------- --------------$-------------

8181 29 23 Protein Supplement .48 .36 .24 .12 .10

Mineral/Vitamin .18 .17 .15 .14 .12

Service .10 .10 .10 .10 .10

Total .76 .63 .49 .36 .22

8636 38 28 Protein Supplement 1.00 .88 .76 .64 .52

Fat Supplement .13 .13 .13 .13 .13

Mineral/Vitamin .21 .19 .18 .17 .16

Service .10 .10 .10 .10 .10

Total 1.44 1.31 1.17 1.04 .91

10454 48 35 Protein Supplement 1.56 1.43 1.30 1.17 1.04

Fat Supplement .61 .61 .61 .61 .61

Mineral/Vitamin .23 .22 .21 .19 .18

Service .10 .10 .10 .10 .10

Total 2.50 2.36 2.22 2.07 1.93

Table 7. Positioning purchased feeds (Hutjens et al, 1991).

Undegraded protein Milk yield > 30 kg

Animal/fish protein blend Milk yeild > 40 kg

Corn based diets

Unprotected fat/oil Milk yield > 35 kg

Thin cows

Protected fat Milk yield > 40 kg

Thin cows

Chelated/complex minerals Close-up dry cows

E.T. donor cows

Stress conditions

Buffers Early lactation

Wet rations

High corn silage rations

Niacin Close-up dry cows

Early lactation

Milk yield > 35 kg

Yeast Close-up dry cows

Fresh cows

Cows off-feed

Anionic salts Close-up dry cows

Probiotics Calves on liquid diets

Cows off-feed

« Back to Dairy Cattle