Measuring Feed Efficiency On Farms
Introduction
Feed efficiency (FE), also known as milk performance efficiency can be defined as pounds of 3.5% fat-corrected milk (FCM) produced per pound of dry matter (DM) consumed. Feed efficiency is commonly used in the beef, swine or fish industry as a benchmark for profitability but it is still not widely used in the dairy industry. The main focus on feed efficiency is based on the idea that as cows consume more feed, digestive efficiency will decrease. This is because the relationship between net energy lactation intake and milk production is subject to diminishing returns.
Practical Ways To Measure FE On Farms
1) Computer Software
The computer software will allow on-farm data that will standardise the FE values. Farmers can use spreadsheets to enter days in milk, body weight, milk fat test, milk yield, BCS, temperature of the environment, walking distance and so on to adjust values.
2) On-farm Measurement of FE
This method involves collecting dry matter intake by group or herd using actual feed amount delivered with automated computer tracking systems. After that, subtract any feed refusals and collect daily milk yield using a group total or individual cow production summaries. An example is shown in the table below:
3) Estimating And Adjusting For FE
Many farmers will opt for this method due to limitations such as feed intake by groups not measured daily, weigh backs not measured, no group or pen milk components available.
By using this approach of estimating FE, the following factors can be used along with bulk tank milk yields and ration summaries. Take a herd of about 100 cows for example that averaged approximately 6,800 pounds of milk and consume around 4,800 pounds of dry matter. The FE is 1.42 for this herd. Nutritionist can adjust these values as data are not available for several of these factors.
Factor 1: Weigh Back. Estimate the feed refusal using a bunk scoring system.
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Feed bunk score of 1: No feed remaining
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Feed bunk score of 2: 2 - 4% remaining
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Feed bunk score of 3: over 5% remaining
As an example, if the feed bank score is 3 based on our example earlier, the weigh back would represent 2.4 pounds. Hence, the adjusted FE is 1.49.
Factor 2: Days in milk (DIM). Add 0.15 FE unit for each 50 days starting at 150 DIM. Using our herd example, if the DIM is at 200 days, the adjusted FE would be 1.57.
Factor 3: Somatic cell count. For each linear score decrease in SCC, add 2.5 pounds of milk to the current production. Take our herd example, if the linear score decreases from 4 to 3, add 2.5 pounds, so the production is at 70.5 pounds. Adjusted FE would be 1.47.
Factor 4: Change in BCS. If cows gaining 0.5 BCS, 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, adding 1.4 pounds of milk to the base result, this will have an adjusted FE of 1.45.
Factor 5: Exercise. If cows walk around 800m per day, this will increase the maintenance requirements by 1.9 Mcal, which is equal to 5 pounds of 3.5 lb FCM. Adding this amount to the example herd, the adjusted FE would be 1.52.
Factor 6: Rumen acidosis. Research shows that FE can drop 0.1 unit if cows are experiencing subacute rumen acidosis.
Factor 7: Protein level and form. Study shows that level of protein can impact FE. An animal protein blend increased the FE by 0.07 unit compared to soybean meal.
Factor 8: Feed additives. Adding additives such as yest, ionophores and buffers can increase FE by 0.05 - 0.10 unit.
Factor 9: Fiber level. Increasing NDF (neutral detergent fiber) % in the ration dry matter can cause FE to decline.
Factor 10: Heat stress. Cows experiencing heat stress will cause FE to decline. For example, cows exposed to environmental temperature of 30°C compared to 20°C have a reduction of FE by 0.1 unit.