In February, 2008, milk to feed ratio was 2.36 in Illinois. A milk to feed ratio under 3 signals that feed inputs must decrease. Feed efficiency (also referred to as milk performance efficiency and dairy efficiency) can be defined as pounds of 3.5%FCM (fat corrected milk) produced per pound of dry matter (DM) consumed.
Feed efficiency (FE) has not been a common profitability benchmark in the dairy industry. Feed efficiency reflects the fact that as cows consume more feed, digestive efficiency decreases and milk production is subject to diminishing returns. “Traditional” thinking was that when cows ate more feed and produced more milk, the proportion of digested nutrients captured as milk was proportionally higher.
Economics of feeding programs
When evaluating feeding changes, the impact on profitability must be considered. Several measurements may be used; each has advantages and disadvantages.
Feed cost per cow per day does not reflect milk yield, stage of lactation, or nutrient requirements. Illinois target value is less than $5.50 per cow per day for Holstein cows at 70 pounds of milk. An application of this value is to sum all feed components to determine if costs are optimal for herd production and local feed costs.
Feed cost per pound of dry matter is a useful term when comparing similar regions, breeds, and levels of milk production. The current target value in Illinois is 10 to 11 cents per pound of dry matter.
Feed cost per 100 pounds (cwt) of milk standardizes milk yield, allowing comparisons between groups and farms within a region. Milk yield per cow and feed costs will impact this value. Less than $7.00 per cwt for Holstein cows is the current Illinois target.
Income over feed costs (IOFC) is a popular value that provides a benchmark for herds or groups of cows reflecting profitability, current feed prices, and actual milk prices. With correct fixed costs and variable costs, IOFC can be used to determine breakeven prices, optimal dry off time, and culling strategies. The current Illinois target is over $11 per cow per day ($18 per cwt).
Marginal milk response reflects the profit if additional pounds of milk are produced. Generally, maintenance and fixed costs have been covered by previous production. For example, if adding one pound of dry matter increases milk yield by two pounds with milk valued at $18 per cwt and dry matter at 10 cents per lb., the marginal milk profit is 26 cents.
Cost per unit of nutrient compares the relative costs of nutrients. Forages, by-product feeds, and other cereal grains can be compared on cost per unit of nutrient to the base energy-feed resource (generally corn in the USA).
Feed efficiency can be defined as pounds of milk produced per pound of dry matter consumed (DMI). Guidelines for FE are listed in Table 2.
Table 2. Benchmarks for feed efficiency comparisons.
| Group |
Days in milk |
FE (lb milk/lb DM) |
| One group, all cows |
150 to 225 |
1.4 to 1.6 |
| 1st lactation group |
< 90 |
1.5 to 1.7 |
| 1st lactation group |
> 200 |
1.2 to 1.4 |
| 2nd + lactation group |
< 90 |
1.6 to 1.8 |
| 2nd + lactation group |
> 200 |
1.3 to 1.5 |
| Fresh cow group |
< 21 |
1.3 to 1.6 |
| Problem herds/groups |
150 to 200 |
< 1.3 |
Approaches to measuring FE on farms:
Option 1. Computer software program. An example is FeedAd, developed by Zinpro Corporation for field application. On-farm data is used to standardize FE values by accounting for factors such as days in milk, body weight, milk yield, milk fat test, milk protein test, changes in body condition score, environmental temperature, walking distances, and lactation number.
Option 2. On-farm measurement of FE. Dry matter intake is determined by group or herd using actual feed amount delivered with automated computer tracking systems (such as Feed Tracker), subtracting feed refusals, and collecting daily milk yield using either group totals or individual cow production.
Option 3. Estimating and adjusting for FE. Dairy managers and nutritionists are often forced to use this option due to the following situations:
- Milk yield is available monthly from DHI or daily bulk tank yields.
- Feed intake by groups or herd is not recorded daily.
- Weigh backs may or may not be measured.
- No group or pen milk components are available.
If FE must be estimated, the following factors can be used along with bulk tank milk yields and ration summaries to fine tune estimates. These estimations may also be used to evaluate potential feeding and/or management changes.
Factor 1: Weigh back factor. Estimations of feed refusals can use a bunk scoring system based on a subjective estimate.
Feed bunk score 0 has no feed remaining
Feed bunk score 1 has 1 lb of dry matter remaining per cow
Feed bunk score 2 has 2 lb of dry matter remaining per cow
Factor 2: Days in milk (DIM). Add 0.15 FE unit for each 50 days starting at 150 DIM.
Factor 3: Somatic cell count. For each linear score change in SCC, add or subtract 2.5 pounds milk to the current production.
Factor 4: Change in body condition. If cows are gaining one half body condition score during lactation, this milk equivalent can represent 138 pounds of milk (60 pounds of body condition equals 2.3 pounds of milk per pound). If this occurs over 100 days, add 1.4 pounds of milk to the base milk yield.
Factor 5: Exercise/pasture. Subtract 0.2 lb of milk for every 100 feet cows walk daily to account for increased maintenance requirements.
Factor 6: Rumen acidosis. Field reports estimate that FE may drop 0.1 unit if cows experience sub-acute rumen acidosis (SARA). Diagnosis could be based on several field indicators.
- Milk protein: milk fat ratio over 0.9
- Loose manure (average manure scores under 2.75)
- Average lameness scores over 1.6
- Daily dry matter intake varies by more than two pounds per cow per day
Factor 7: Protein level and form. Illinois data indicate that level of protein can impact FE. If protein is over 18 percent crude protein or MUN are over 16, shift FE by 0.03 unit. Better yet, adjust protein feeding.
Factor 8: Feed additive. Adding yeast culture/yeast, ionophores, buffers, and direct-fed microbials may increase FE by 0.05 to 0.10 unit per additive if milk responses occur.
Factor 9: Fiber digestibility. As forage NDF (neutral detergent fiber) digestibility increases one percent point (more digestible), milk yield increases 0.5 pound of milk and dry matter intake increases 0.25 pound.
Factor 10. Heat stress. Heat stressed cows have lower FEs due to higher maintenance requirements, lower milk yield, and lower feed intake. Cows exposed to 86 degrees F compared to 68 degrees F, reduce FE by 0.1 unit. Cows exposed to 95 degrees F compared to 86 degrees F, lower FE by 0.3 unit.
Fresh cow monitoring of FE
For dairy managers and nutritionists that have a fresh cow pen with daily milk yields, group feed intakes, and days in milk recalculated daily, FE is a useful tool to compare heifer and mature cow fresh pens, and monitor success of the transition program. A California field study of 50 herds reported fresh heifer groups had an average FE of 1.47 with a range of 1.19 to 1.87 (days in milk was not reported).Mature cows averaged 1.75 with a range of 1.26 to 2.26.
A low FE is good if dry matter intake after calving is acceptable. However, low FE can reflect low milk production in early lactation, a potential problem. A high FE can indicate cows are achieving high milk after calving (good), low dry matter intake after calving (bad), and/or excess weight losses leading to ketosis and fatty liver development (bad). Table 4 lists dry matter intake guidelines by week after calving and parity.
Table 4. Dry matter intake by week after calving and parity (Hutjens, 2005).
Week after calving 1st lactation cows 2nd+ lactation cows
--------- lb per cow per day-------------
| 1 |
31.0 |
36.5 |
| 2 |
35.0 |
42.5 |
| 3 |
38.0 |
45.5 |
| 4 |
40.0 |
49.0 |
| 5 |
41.5 |
52.5 |
Economics of feed efficiency
Low milk:feed ratios, one way to maintain profitability without sacrificing milk production or herd health is by enhancing feed efficiency. Table 5 illustrates the impact of improved FE with constant milk production and feed costs.
Table 5. Economic impact of improving FE while maintaining milk yield.
| FE |
DMI |
Savings |
| (lb of milk/lb DM) |
(lb DM/day) |
($/cow/day) |
| 1.20 |
58.3 |
- |
| 1.40 |
50.0 |
0.83 |
| 1.60 |
43.8 |
0.62 |
| 1.80 |
38.9 |
0.48 |
Optimizing feed intake is the “magic” term; not maximizing DMI. Higher nutrient demand for higher milk production leads to maximum DMI. The more DMI the cow eats, the more she must milk to achieve higher FE values. Composition of the diet (forage to grain ratio) and dry matter intake (multiples of maintenance) has marked effects on digestibility and subsequent energy values. Diets that do not promote optimal rumen fermentation will result in an over-estimation of energy values and poor feed efficiency.
Fine tuning feed efficiency
Actual and accurate feed intake is critical for an accurate FE value. Feed refusals must be subtracted, as this feed has not been consumed. Weekly dry matter tests are necessary to correct for variation in dry matter intake due to changes in wet feeds or precipitation. Correct for milk components since more nutrients are needed as milk fat and protein content increases. Values reported in this paper are based on 3.5 percent fat corrected milk (3.5%FCM). The following formulas can be used:
Equation 1: 3.5% lb FCM = (0.4324 x lb of milk) + (16.216 x lb of milk fat)
Equation 2: 3.5% lb fat and protein corrected milk (lb) =
(12.82 x lb fat) + (7.13 x lb protein) + (0.323 x lb of milk)
Summary
- Feed efficiency reflects the level of fat-corrected milk yield produced per unit of dry matter consumed with an optimal range of 1.4 to 1.9 pounds of milk per pound of dry matter.
- Days in milk, age, growth, change in body condition score, walking distances, body weight, forage quality, feed additives, and environmental factors will impact feed efficiency values.
- Dairy managers should monitor changes in feed efficiency as feeding and management changes occur to evaluate the impact of the change.
- Several approaches can be used in the field to measure or estimate FE in groups, herds, and with feeding/management changes.
Selected references
Casper, D, L Whitlock, D. Schauff, and D. Jones. 2003. Feed efficiency boosts profitability. Hoard’s Dairyman Magazine. Sept 25.
Casper, D.P., L. Whitlock, D. Schauff, D. Jones, and D. Spangler. 2004. Feed efficiency is driven by dry matter intake. J. Dairy Sci. 87 (Suppl. 1):462, Abstract 933.
Hutjens, M.F. 2001. Where are you on feed costs? Hoard’s Dairyman. Jan 20
Hutjens, M.F. 2005. Feed efficiency and its impact in large dairy herd. Southwest Nutritional Conf Proc.
Hutjens, M.F. 2007. Applied Feed Efficiency on Dairy Farms. Penn State Dairy Workshop Proc.
Linn, J, T.Trulla, D.L. Casper, and M. Raeth-Knight. 2004. Feed Efficiency of lactating dairy cows. Minnesota Nutr. Conf. Proc.
Veerkamp, R.F. 1998. Selection for economic efficiency of dairy cattle using information on live weight and feed intake: A review. J. Dairy Sci. 81-1109-1119
Wang, S, G.L. Roy, A.J. Lee, A.J McAlliser, T.R. Batra, and C.Y. Lin. 1992. Evaluation of various measurements of and factors influencing feed efficiency in dairy cattle. J. Dairy Sci. 75:1273-1280.
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