Nutritional needs of the cowherd

By Mark Johnson, Oklahoma State University Extension

As we approach the winter months and the time of year when feeding harvested forage becomes the norm, we turn to the topic of the cowherd’s daily nutritional needs. Pasture and feed expenses represent approximately 42 to 52 percent of the input costs of a cow-calf operation. Knowing the nutritional needs of cows helps producers meet their needs profitably. Both overfeeding or underfeeding robs the profit potential of cow-calf operations. During the normal production cycle, cows should gain weight and body condition during the dry phases and lose weight and body condition while nursing a calf. With this in mind, it is optimal to have cows with a BCS of 5 to 6 before the calving season. This means that cows are in good shape and have sufficient energy reserves to draw on when the “peak” in crude protein (CP) and energy requirements (TDN) occurs after calving, as the cow begins lactation . Cows must be in good condition at the start of the calving season to reduce the breeding interval and stay on schedule to breed, calve and raise a calf to weaning every 12 months.

Assuming an adequate supply of good quality water and an adequate vitamin and mineral supplementation program, the two main nutritional requirements of cows are CP and TDN. In normal weather, there are three main influences on the daily needs of both:

1 – Adult weight

2 – Level of milk production

3 – Production stage

Where cows are currently in the production cycle and when they will begin to calve should be considered when making management decisions regarding feeding. The example below follows a 1,300 pound cow through a normal production cycle during the middle trimester of gestation, the last trimester of gestation, and the first 90 days after calving, depending on her level of milk production.

During the middle third of gestation, the 1,300-pound adult cow needs:

The same 1,300 pound cow in the last third of her gestation needs:

Increased nutritional requirements reflect not only the maintenance needs of the cow, but also the increased growth and development of the fetus as calving approaches.

After calving, during the first 90 days of lactation, the same 1,300 pound cow will have increased nutritional needs based on the amount of milk she produces:

If she is giving 25 pounds of milk per day at peak lactation, she will need:

If she gives 35 pounds of milk per day, she will need:

In summary, the same cow has protein and energy requirements that increase and decrease significantly during the normal production cycle. Knowing these requirements is essential for profitable feeding of the cow herd. Proper management of a nutritional program plays a huge role in reproductive performance.