“Feeding cows is part science and part art; the trick is finding the sweet spot,” says Mike Hutjens, extension dairy specialist for the University of Illinois.

Hutjens recently addressed tools that can help your dairy operation be more profitable.

Hutjens says all dairies should be operated “first and foremost as businesses, and the bottom line is feed efficiency.”

It is important to look at feed efficiency (FE) as the pounds of fat-corrected milk divided by pounds of dry matter consumed, he says. High-producing groups should have a feed efficiency of 1.7 or above, while fresh cows should be at 1.5, and low groups are typically below 1.3.

“Feed efficiency is a powerful tool to answer how efficiently your herd converts feed inputs to milk output. Feed efficiency is the key benchmark for poultry, swine and beef producers,” Hutjens says.

Accurate feed intake is critical for an accurate FE value. Feed refusals should be subtracted, as this feed has not been consumed. Weekly dry matter tests should be conducted on the farm to correct for variation in DMI (dry matter intake) due to changes in wet feeds or precipitation. Producers should make corrections for milk components as more nutrients are needed as milk fat and protein content increases. Values reported in this article are based on 3.5 percent FCM (fat-corrected milk). The following formulas can be used:

• Equation 1:
  • 3.5% pounds FCM = (0.4324 x kg of milk) + (16.216 x pounds of milk fat)
• Equation 2:
  • 3.5% pounds energy-corrected milk = (12.82 x pounds of fat) + (7.13 x pounds of protein) + (0.323 x pounds of milk)

Factors that impact feed efficiency the most that dairy producers need to be aware of include: forage quality, feed digestibility, increasing the pregnancy rate (resulting in more cows in early phases of lactation), lowering somatic cell counts, increasing milk yield and reducing the risk of acidosis. Other factors include feed additives, age of cows, rBST use, heat stress, along with protein form and level.

On Holstein farms, use the thumb rule of adding or subtracting 1 pound of milk for every one-tenth percentage point change above or below 3.5 percent fat test. For example, if a herd averages 70 pounds of milk with a 3.9 percent milk fat, the estimated pounds of 3.5 percent FCM would be 74 pounds instead of 70 pounds. The economic impact of feed efficiency is another key factor when shifting FE values. If a herd or group of cows producing 70 pounds of milk with an FE of 1.4 changes to an FE of 1.5, the average DMI drops 3 pounds. If dry matter is valued at 10 cents per pound, this improvement in FE results in a savings of 30 cents per cow per day, or 24 cents per 0.1 point increase in FE. A FE of 1.3 with a DMI of 54 pounds compared to a FE of 1.4 and a DMI of 50 pounds a day will save you 40 cents a day.

Hutjens notes other useful feed benchmark measurements include: feed cost per pound of dry matter (target 10 to 12 cents per pound), feed cost per hundredweight (cwt) of milk (target less than $7), and income over feed costs (target more than $10 per cwt but depends on current milk prices).

Other important things to monitor that Hutjens recommends include grain particle size (average 500 to 800 micron), TMR particle size using the Penn State particle box (10 percent in the top box, greater than 40 percent in the middle box and less than 50 percent in the bottom pan), silage fermentation (percentage of lactic acid to acetic acid), feed efficiency and milk urea nitrogen (8 to 12 mg/dL).

For particle size, Hutjens says, “Send a sample to the forage lab and get a mean particle size and a spread in particle size.” An average particle size provides a benchmark, while different particle sizes impact the rate and extent of starch fermentation in the rumen.

Recommended fermentation profiles for ensiled feeds include:

• Corn silage: 30 to 35 percent DM, pH of 3.8 to 4.2, 5 to 7 percent lactic acid, 1 to 3 percent acetic acid, and propionic and butyric acid below 0.1 percent
• Legume/grass silage: 35 to 50 percent DM, pH of 4.3 to 4.7, 4 to 6 percent lactic acid, 0.5 to 2.5 percent acetic acid, and butyric acid below .25 percent
• High-moisture corn: 70 to 75 percent DM, pH of 4.0 to 4.5, 1 to 2 percent lactic acid, less than 0.5 percent acetic acid, and propionic and butyric acid below 0.1 percent

Hutjens says samples of wet silage or high-moisture corn should be sent to a commercial lab requesting fermentation profile analysis, especially when changing forage sources, cutting or storage units.

Hutjens recommends using uNDF (undigested neutral detergent fiber) as a way to determine rumen fill from forage sources; uNDF estimates the undigested NDF residue after fermentation/digestion at a given length of time, and that figure is usually accompanied with the number of hours of fermentation/digestion (30, 48, 120 or 240 hours are commonly used). His guidelines are 6 to 6.2 pounds of uNDF30 for Holsteins and 5 pounds uNDF30 for Jerseys. He gives this example for Holsteins: a 30 percent ration NDF x 50 pounds DMI x 40 percent uNDF = 6 pounds uNDF. “This herd should be able to consume this level of DMI based on uNDF levels,” he says.

“Dairy managers can calculate this value as forage sources and types change in their ration due to forage type, quality, and/or amount fed and monitor herd performance,” Hutjens says.

Manure scores (using the 1-to-5 point system with a score of 1 extremely loose, score 3 ideal and score 5 stacking and solid) can also be a useful tool to determine if the cows are getting enough starch. Ideally, high-producing pens should have less than 10 percent of the manure with a score of 1 and 25 percent of the manure with a score less than 2. Low-producing pens should have less than 10 percent of manure scores at 2 or less.

Measuring the amount of starch remaining in manure can provide answers if starch is not being fermented or digested. “Fecal starch should be less than 4.5 percent, representing total tract digestibility of 90-plus percent,” Hutjens says. “If fecal starch can be reduced one unit [i.e., a decrease of 10 to 9 percent], milk production could increase 0.67 pounds with dry matter intake remaining the same.”

He noted the new recommended MUN (milk urea nitrogen) values are 8 to 12 mg/dL. Herds with MUN numbers of 16 and above may have reproductive concerns. Hutjens recommends that dairy producers also know their cows’ locomotion and body conditioning scores. Hutjens concludes, “The bottom line is to use these on-farm tools to evaluate opportunities to improve milk production and profitability. Use your criteria and adjust the values to fit your farm when removing bottlenecks in your feeding system.”  PD

Kelli Boylen is a freelance writer based in Iowa.

PHOTO: With feed costs the largest expense in milk production, the biggest opportunity to save cost is to increase feed efficiency. Graphic by Mike Dixon.