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Improving feed efficiency of dairy cows with probiotics

Dave Lindevig Published on 23 June 2015

Feed efficiency is a common method used in beef, swine and poultry operations to determine profitability and performance. This is a fairly easy calculation based on feed per pound of gain; however, with respect to dairy operations, the calculations become more complicated due to the number of variables that go into milk production.

With the cost of feed increasing over the last few years, dairy operations are more attentive to the amount of feed that it takes to produce a pound of milk. Numerous equations have been developed to address the question of dairy efficiency. The two that are currently used by most dairy operations and nutritionists are feed efficiency and income over feed cost.



Feed efficiency is measured by the amount of dry matter feed used to produce a pound of fat corrected milk. Income over feed cost is the amount of income left after all the feed costs are paid. No matter which equation your operation uses, finding ways to improve feed efficiency is imperative. Probiotics or direct-fed microbials are one of the most cost-effective means of improving intake.

As long as the feedstuffs are priced economically, producing more milk per pound of feed is profitable for the dairy. To adjust for 3.5 percent fat corrected milk, the equation is .432 x the pounds of milk + 16.23 x the pounds of fat. For a Holstein cow, a simple rule of thumb is 1 pound for every tenth of a point over 3.5 percent, so with a 3.8 percent butterfat, there would be an additional 3 pounds added onto the average milk production.

The feed efficiency is dependent upon a number of variables, but for an average herd, it generally ranges between 1.4 and 1.9. If the herd is outside this range, then adjustments to the diet may be necessary.

Income over feed cost is calculated based on the current price per pound of the forage and grain raised on the farm; this should be calculated by the price of feed sold on the open market. In addition, all of the purchased feed – including transportation costs – needs to be added into the amount. It is important to calculate the feed shrinkage along with any refusals from the cows. Once all of these amounts are totaled, subtract the total cost of the feed from the mailbox price of milk. Continuing to track this throughout the year gives the best indicator of the profitability.

There are two times during the life of a dairy cow that have the most influence on the feed efficiency and income over feed cost. The first is during the calf’s life up to weaning. Research has proven that if the calf is fed higher quality nutrition, it may produce up to an additional 1,500 pounds of milk per lactation compared with calves who received low quality feed. Probiotics have been shown in a number of research trials to increase the intake of the calf, which helps to improve the calf’s nutrition and ability to fight off disease.


Calves are born without either good or bad bacteria in the digestive tract; a probiotic supplement helps to get the good bacteria into the animal before the bad ones take over. Providing probiotics at birth is the greatest factor in increasing feed efficiency later during the cow’s lactation. This is also the time when a probiotic is the lowest cost. Just one bolus at birth will give the calf additional good bacteria to help it to naturally ward off the pathogens.

The second most critical time is during the transition period, when a dry cow or heifer enters the lactating herd. The single most important part of the transition period is to increase the dry matter intake two to three weeks prior to freshening and one to two weeks after freshening. The need for energy after calving doubles, so dry matter intake is an important indicator of success. Once a cow has calved, the inclusion of a bolus or gel probiotic in the diet will help improve intake to meet the additional energy needed during the first weeks of the cow’s lactation.

Improved intake also reduces the metabolic issues associated with low energy. A large portion of the feed efficiency and income over feed costs are determined by the way the cow is handled during this five-week period. Taking a little time to give a probiotic may pay big dividends through decreased treatment costs, increased milk production and improved breeding.

There are a number of times during a cow’s life when probiotics may improve the efficiencies and profitability of the dairy operation. Probiotics are recommended during challenges that all animals face: weather or diet changes, weaning, birthing, after antibiotic therapy and acclimation. Gel or bolus probiotics are relatively easy to give to calves and transition cows, and are a cost-effective way to increase feed efficiency and income over feed cost. PD

Dave Lindevig is a national accounts manager at Vets Plus Inc.