Ensuring that cows receive adequate nutrition after calving is critical.
“The first 60 to 90 days post-calving is the most nutritionally demanding period in the production cycle of a cow and arguably one of the most important in achieving production goals,” says Janna Kincheloe, the North Dakota State University Extension Service’s livestock systems specialist at the Hettinger Research Extension Center.
Peak milk production typically occurs about 60 days after calving in mature cows and requirements are highest at this time. Nutritional stress caused by calving and/or lactation can have a substantial impact on productivity.
A cow uses the total nutrients (water, energy, protein, vitamins and minerals) it consumes each day based on these biological priorities: maintenance, growth, lactation and reproduction. Because reproduction is lowest on the priority list, it is one of the first factors affected if nutrition is inadequate between calving and breeding.
Research indicates that pregnancy rates will be reduced when cows have body condition scores of less than 5 at calving and breeding. This is particularly true for high-producing cows and 2- and 3-year-olds that still have requirements for growth.
“A reasonable estimate of milking ability is necessary to ensure that available feed resources can support the cow herd,” Kincheloe says. “If milk production is too high for a given environment, negative impacts on cow performance and calf weaning weight will reduce profit potential.”
Expected progeny differences (EPDs) for maternal milk production, as reported by breed associations, are expressed as differences in pounds of calf weaned due to milk production of the dam. The livestock industry has seen a strong genetic trend of increased milk production in nearly all beef cattle breeds during the past 20 years, with the average commercial cow estimated to produce about 25 pounds of milk each day during peak lactation.
While directly measuring milk production in a range or pasture is challenging, producers can use calf weaning weight records as an indirect estimate. Kincheloe suggests producers keep in mind that environmental conditions and other genetic traits such as growth potential also impact weaning weights.
Understanding how nutrient requirements of beef cows vary based on weight and stage of production is important. For example, a 1,200-pound cow at peak milk production of 20 pounds two months after calving requires about 3 pounds of crude protein a day, while the same cow producing 30 pounds of milk requires nearly 3.75 pounds of crude protein a day.
The timing of calving, age of the dam, and forage quality and availability will determine the most appropriate feeding strategy.
Native range generally can meet lactating cows’ nutrient requirements in the northern Great Plains during peak forage production in late May and early June, Kincheloe says. However, cows that have calved prior to the first part of April will reach peak milk production before most forage species will be able to provide necessary nutrients.
In addition, turning cows out to pasture too early will reduce forage health and production, as well as animal performance. Therefore, producers often need to supply higher-quality forages and/or supplements in early spring to support cows’ increased requirements during lactation.
A variety of protein and energy supplements are available to help fill nutritional gaps from forage. Kincheloe recommends supplements containing at least 20 percent protein when feeding low-quality forage (7 percent or less crude protein). These supplements include feeds such as alfalfa hay, soybean meal, commercial supplements and distillers grains.