Pounds of beef sold is a key number for cattlemen. Late calvers the cows that drag out the calving season, may cost producers more than extra work and management, they may actually be costing dollars.

Standardized Performance Analysis (SPA) has been around for decades. This tool helps determine what the actual costs to raise a calf from breeding to weaning. Many producers create a budget for marketing and financing purposes, but SPA calculates the real, final costs. Use of both tools provide the opportunity for producers to evaluate the accuracy of the budget they created and also looks for problem areas in the operation.

Calving Intervals: Comparing Herds

One area of analysis provided by SPA is calving interval. Based on 21-day cycles, the calving interval determines the age of the calf at weaning and correlates to the size (pounds) of calf sold at weaning. For example, compare two herds, with varying calving intervals (Table 1).

Both herds begin calving April 1st, with 200 head calved, and there were no death losses reported.

• Herd 1 had an expected calving season with 13 cows, or 6.5%, of the herd calving more than 85 days after the first calf was born. The average weaning weight for herd 1 was 489 pounds, received an average of \$1.57/pound, for a total return of \$153,499.78.
• Herd 2 had a very tight calving season with 98.5 percent calving within the first 42 days of the season. The average weight was 536 pounds and had an average selling price of \$1.49/pound for a return of \$159,559.31.

Analysis
Based on similar situations Herd 2 even while receiving less on a per pound basis, returned \$6,059 more than Herd 1, due to changing the average calving date and thus, the total weight sold.

Table 1. Herd comparison with varying calving intervals.

Considerations

Labor at Calving
With a large percentage of the cows calving within a narrow time frame, cattlemen will be busy tending to cows as there will be a larger number of calves born per day during this window. However, the labor requirements for calving season will be much narrower as the main need is 42 days in the Herd 2 example. After calving, time can be spent on other projects of the operation (ex. Crops planning, haying, etc.).

Bull Power
Bull power, either through artificial insemination (AI) or natural service needs to be considered. Both require additional costs for the operation. In order to narrow the calving interval a synchronization protocol will typically need to be utilized. This requires labor to move cows through the chute multiple times for the synchronization protocol and then again to AI the cows, as well as for heat detection if timed-breeding is not utilized.

If AI is not utilized, additional bulls will need to be raised or purchased to adequately cover the number of cows cycling at the same time. More owned bulls will result in additional feed costs and space to house them during the non-breeding season months.

Facilities
Calving a larger number of cows than before at one time may require the adaption of facilities to house the cows during their last weeks of gestation as well as cow-calf pairs.

Calving Date
Cattlemen may also want to consider when they calve if they plan to narrow their calving season. Changing from April 1st to May 1st calving may allow for cows to be calved on pasture, without as much weather or mud risk. This change should take into consideration other activities on the operation during May, and if everything can be appropriately managed following the change.

Sale Price
As noted in the two example herds, the price for calves varies by weight. Cattlemen should consider what the price difference is at their traditional sale barn. Also, the price difference between steers and heifers should be considered. In the example all calves were considered males.

Record Keeping
The first step to analyze your calving intervals is date, then knowing how many cows calved and when. These numbers can either be found in a calving book or using any other counting method (a calendar with tick marks indicating how many calved each day is fine.)

The Bottom Line

A calving interval may not seem like something to manage. However, your herd may be giving up income potential that could be rectified in the 2017 breeding season. SDSU Extension has synchronization resources and Cow/Calf Field Specialists available to assist with changes in calving intervals and Farm Management Field Specialists available to assist with the Standardized Performance Analysis (SPA).

Standardized Performance Analysis Help:

Calving Interval Help:

Resources: