A Good Year To Shorten Breeding Season

Phil Osborne, Ph.D.
Livestock Marketing Extension Specialist
WVU Extension Service
10/1998

West Virginia beef producers may have a real opportunity this year to shorten the breeding season. Reducing the calving season to 45 to 50 days for replacement heifers and 60 to 70 days for cows has some real economic advantages. The open winter with minimal snow cover and mild temperatures permitted most cows to carry good body condition all the way through calving. Cows maintaining a body condition score of 5 (moderate flesh) will cycle sooner and rebreed earlier at a higher rate.

There are a number of reasons for maintaining a short breeding season:

1. Marketing - A short breeding season allows for a more uniform calf crop. This is particularly important when participating in a feeder calf marketing pool. Most pools want to market trailer loads of calves of uniform age and within a 100 lb. weight spread. Even in a 70-day calving season your calf crop can have as much as a 126 to 140 lb. weight spread if the average daily gains are 1.8 to 2.0 lbs. respectively. The calves born in the early part of the calving season will return $107.00 per head (@$ .85/lb.) more than the later born calves.

2. Time and labor - A controlled calving season concentrates time and labor for calving, reduces expenses, and increases efficiency. This is especially important for first-calf heifers and small part-time operations where it is most difficult to closely watch cows. Most calves are lost at the very beginning of the season, when they are not expected, and at the end of a long calving season, where producer fatigue plays a major role. It is very difficult to properly check cows that are on a year round calving season.

3. Herd health - The herd health and management of the cow herd is better facilitated with a shortened calving season. The economically important practices, such as vaccination, castration, identification, deworming, and weaning, are best accomplished with less labor. The length of the calving season greatly influences the timing of pregnancy testing, marketing, culling cows and proper nutritional management.

4. Nutrition - Brood cow nutritional management can be improved when all cows are in the same stage of production. The winter feeding of the cow herd is the most expensive phase of production. With a controlled calving season, dry cows can utilize stockpile forages and lower-quality hay. High-quality hay can be reserved for nursing cows. Cows nursing calves need 50 percent more protein than dry cows; so, supplementation and expense savings can be better achieved if all cows are in the same stage of production. Neither group can be fed properly if they are running together.

5. Selection - Culling and selection of replacement heifers based on records can be better accomplished. More interest and emphasis are being placed on production and carcass data. Producers need to make comparisons of contemporary groups, which is better achieved in a short calving season. Accurate comparisons between cows cannot be made if the calving season is too extended. Weaning weights will improve along with reproductive performance of the herd if cows failing to breed during the calving season are marketed.

The major excuses producers give for failing to maintain a short calving season:

1 Bulls: Removing bulls and keeping them separate is a problem for most small operations. However, with high tensile electric fence, bull lots can be constructed economically and double as weaning lots when preparing calves for the market. If a bull cannot be removed until weaning, pregnancy checking and culling late breed cows is a method of shortening the calving season.

2 Open cows: Producers fear that they miss calves if they go on a controlled breeding season. Some even feel they can breed more cows to a bull on a year round program. The truth is that cows failing to calve on a controlled breeding program are stealing from you. Most wean calves too light to cover annual expenses of owning the cow. Producers marketing feeder calves in the Performance Advantage Sales have reported $5.00 to $8.00/cwt discounts on calves failing to qualify due to being too light for the load. Body condition score have to be monitored on a controlled calving program. Cows that are not in good condition or grazing poor pasture are likely candidates to be open. A controlled calving season forces late and slow breeding cows out of the herd.

If a producer decides to shorten the breeding season from 120 days to 70 days, the length of the previous calving season should be analyzed to estimate the number of cows that may be open after the breeding season. It may be desirable to gradually shorten the breeding season over a couple of years. Producers should take advantage of the natural concentration of calving in a herd. Steps to starting a controlled calving season include:

1. Build a good strong bull/weaning pen or pasture.

2. Remove the bull from the herd. Select removal date to coincide with the latest you want calves. For marketing calves in the fall, a July 4 target date is usually optimum. For wintering calves for yearlings, a July 20 date is a good target for removal.

3. If you want to shorten the calving interval over a couple years it is best to turn the bull out 10 days later and remove it 10 days earlier than when the majority of the calves were born that spring. Follow this sequence for a couple years until you reduce the calving season to 70 to 80 days. Most producers after the first year only want to shorten the season by timing the removal of the bull.

A short 30- to 45-day breeding season for replacement heifers is especially important to select the most fertile heifers and to reduce labor at calving. An estrous synchronization program with heifers can be beneficial by reducing the breeding season 10 to 15 days. It allows the use of calving ease bulls and provides service dates for predicting when the first calves are due.

Producers wanting to utilize estrous synchronization in the cow herd will have the greatest success in a herd where a controlled breeding season is utilized. Generally, the cows that have calves at least 50 days old by the beginning of the breeding season are the best candidates for success with artificial insemination.

A controlled calving season is best correlated to a good forage program. Many times the quality of the hay and forage is reflected in the reproductive performance of the cow herd -- thus the length of the calving season.

In a natural, uncontrolled environment most cows will naturally concentrate calving in March and April, corresponding with the spring flush of grass in May and June. To maintain a controlled calving season that begins in February will require high-quality forage being fed to cows nursing calves.