Preparing beef females for breeding success this spring

Reproductive success is the most important factor for cow/calf operation profitability. Each cow or heifer only gives producers one calf per year on average if all goes perfectly. Management decisions made throughout the year, and especially prior to breeding, can affect the cow’s ability to produce a calf.

Breeding season is right around the corner for many Wyoming spring-calving operations. This article discusses a few of the important considerations which could increase success.

Evaluate body condition and manage accordingly

Thin cows, or cows with a body condition score (BCS) of less than five are more likely to be open or breed late. The amount of fat cover a female has will affect her ability to cycle and become pregnant. 

Thin cows have longer post-partum intervals and will eventually fall out of the 365-day calving cycle or come up open. An open cow costs money and should be culled or managed ahead of time in a way which will allow the cow to put on more fat. This can be done by offering higher-quality feed inputs and supplementing protein and/or energy prior to the breeding season. 

Thin cows and heifers should be sorted and managed separately from the rest of the herd. It’s generally beneficial to manage heifers to a little higher body condition, with a BCS of 5.5 or six, so the odds of conceiving during the cow’s second year of production are higher.

Heifer selection

Replacement heifers are selected most of the time based on their phenotypic characteristics; however, there should also be emphasis on non-visual details. Heifers born early in the calving season indicate they were most likely from fertile dams which became pregnant early in the breeding season. This is a good sign the heifer will also be productive and fertile during her lifetime. 

A general rule of thumb is heifers should be managed to reach 55 to 65 percent of the average mature cowherd weight prior to breeding season – heifers should weigh 715 to 845 pounds prior to breeding if mature cows weigh 1,300 pounds. Heifers bred on their second or third cycle are more likely to conceive than those bred on their first ever cycle. 

When possible, use sires that have high accuracy expected progeny differences (EPDs) for calving ease on heifers to decrease coincidences of dystocia. Calving problems early in life can be a sign of continuing reproductive problems.

Reproductive tract scoring and herd health 

One way to decrease dystocia is to emphasize selection of replacement heifers which have larger pelvic areas and developed reproductive tracts. Research has shown heifers with small pelvic areas tend to have more difficulty calving. Heifers with small and soft reproductive tracts are less likely to become pregnant. 

Rectal palpation or ultrasonography can be used to compare these characteristics and assign reproductive tract scores (RTS) on a one to five scale. Each heifer’s RTS will depend on the size and tone of the uterine horns and follicle structure of the ovaries. 

Heifers with more developed tracts score higher and are more likely prepared for pregnancy. Ensure all heifers have gone through a proper vaccination protocol to maintain performance and minimize chances of embryonic losses.

Consider estrus synchronization

Estrus synchronization is a commonly used tool to artificially inseminate groups of cows and heifers during shorter timeframes or all during a specific time; however, the benefits of estrus synchronization are not limited to only females bred via artificial insemination (AI). 

Whether producers AI or not, synchronizing females to be receptive to breeding during a shorter period of time could be advantageous. Shortening the breeding season should translate to a shorter calving season and a more uniform calf-crop. Using a simple and inexpensive one-shot protocol of prostaglandin, such as Lutalyse, while females are exposed to bulls could accomplish this. 

Additionally, using synchronization protocols which include a controlled internal drug release (CIDR) make it possible to induce cyclicity of thin anestrous cows and encourage non-cycling heifers to cycle. Producers should make sure they have enough bull power and a pasture setting which allows for successful breeding during a tighter timeframe. 

These are just a few things to consider while preparing for the breeding season. Reproductive success is essential. Successful reproduction requires good nutrition and good management decisions. 

Chance Marshall is a University of Wyoming Extension Agriculture, Horticulture and Livestock Systems Educator based in Fremont County. He can be reached at cmarsha1@uwyo.edu or 307-332-1018.