After calving, milk production of cows increases rapidly to maximum production at approximately 60 days after calving, and then starts to decline. During this time, the growing calf can meet all its nutrient requirements from milk, although it generally begins to consume very small amounts of forage, but as milk production begins to decline the calf must consume more forage to meet nutritional needs. At approximately 90 to 120 days after calving, forage provides most of the calf’s nutrient requirements, which introduces a management decision: should I creep feed?
The decision to creep feed depends on several factors: feed conversion, formulation of creep feed, and price of cattle relative to price of feed. Creep feeding will generally add weight to nursing calves, but the feed conversion can be very poor. The correct way to compute feed conversion of creep feeding is to divide the amount of feed consumed by the added weight to calves above what would be expected without creep feeding. The calf will generally replace forage with creep feed in their diet, and so there is a substitution of forage consumed by non-creep-fed calves. The substitution results in less than 100% of the creep feed consumed increasing nutrient intake by the calf. Thus, feed conversions can range from 8:1 to 15:1 pounds of feed for each additional pound of weight.
Obviously, improving feed conversion would increase the profit potential of creep feeding. The feedstuffs used in the creep feed make little difference in feed conversion most of the time because cereal grains and high-energy coproducts have relatively similar energy densities. However, the type of forage being consumed can make a difference in the response to creep feeds with large amounts of cereal grains/starch such as when creep feeding fall-born calves, because fall-born calves are consuming lower quality dormant or harvested forage through winter months such that starch has a greater negative impact on forage digestion then when creep feeding spring-born calves grazing tall fescue or smooth bromegrass. In situations with lower quality forages, high-fiber coproducts should be the primary energy source and starchy grains should be limited.
Another primary factor affecting feed conversion is the relative difference between energy density and digestibility of the creep feed versus the forage. In situations where the energy density of creep feed is only marginally greater than the grazed forage, then creep feed conversion will be high. However, the greater the difference in digestibility between forage and creep feed, such as with fall-born calves consuming dormant pastures or harvest hay, the better the feed conversion. Additionally, proper formulation of a creep feed to meet the limiting nutrient in the calf’s diet by complementing the forage such as providing limited amounts of rumen degradable and undegradable protein to meet rumen and calf protein requirements can improve feed conversion. When calves are consuming lower quality forages such as dormant pasture or hay, rumen degradable protein may be limiting the ability of rumen microbes to digest the forage. Young calves whose body weight gain is primarily muscle, have high amino acid requirements and thus providing a creep feed high in rumen undegradable protein can assist in meeting the amino acid requirements. Using a method to limit creep feed intake can also improve feed conversion.
The cost of feed and the price of cattle are also major determinants of creep feed profitability. The cost of feed, along with feed conversion, affects the cost of added weight gain. The cost of adding 1 pound of weight needs to be less than the price per pound of weaned calves. The cost per pound of feed multiplied by the expected feed conversion (pounds of feed per pound of added weight) should be less than the price per pound of calves for creep feeding to be profitable.
There are advantages with creep feeding fall-born calves in that feed conversion can be better than for spring-born calves as the relative difference in energy density between creep feed and forage is greater, especially this year when forages with lesser digestibility than usual may be fed. Additionally, fall-born calves are generally sold at a time when weaned calf prices are higher. However, one disadvantage to creep feeding fall-born calves is that feed costs are generally greater in the winter than the summer. But, as cattle country was gripped by drought last summer and continues to be, the cost of creep feed should also be weighed against the cost and availability of hay to carry the cow herd through the winter. Calves will consume 8 to 10 lb of forage between 6 and 8 months of age, which could be the difference between finishing this winter with enough hay to feed the breeding females.