Splitsal

A common situation in extensive herds is that the sale of stock from one age cohort can be spread over two separate time periods up to one year apart, with the first draft of steers or heifers going when they reach the target weight and the second a year or season later, e.g. some of the bullocks may go at three and a half years, and the balance at four and a half.

Producers will usually have some idea, based on experience, of what proportion they expect to get off at the earlier weight and the average turnoff weights at each age.

But what happens when growth is improved such as by pasture development, a reduced stocking rate, supplementation or genetic improvement? The Splitsal program can be used to consider the approximate change in the proportion turned off from a mob of cattle under such circumstances.

The Splitsal program can be used to:

• predict the effect of increased growth on proportions turned off at each age in a split turnoff and
• estimate average turnoff weights at each age for both growth patterns.

There are no direct links between the Splitsal program and any other Breedcow and Dynama program although sale weights can be manually transferred to Breedcow+ and Dynama+.

Using the Splitsal program

The program is located with the [Breedcow and Dynama Software], within the Tools tab, which can be accessed after registering or logging in to use the free software.

A new scenario can be created by clicking the Save button beside a blank yellow name bar and can be named by typing in the yellow bar. This scenario or previously created scenarios can be edited by clicking the Open button.

To open an example scenario click the Copy button beside the example scenario and it will be copied into your scenario list where it can be opened as your own scenario.

Example one

Copy the User manual example scenario from the examples list and open the scenario, this will illustrate how the program may be used in the following (example one).

In the example, the required weight for turnoff or cut-off weight for a group of steers is 530kg at three and a half years. The average (mean) weight of the mob at three and a half years is estimated to be 500kg with a standard deviation (SD) of 30kg.

Figure 1 below shows the initial data input boxes for the program. The yellow cells are for inputs and can be adjusted, while the rest are calculated outputs.

Figure 1 - Splitsal program data cells

The standard deviation defines the variation of weights either side of the average figure. Users can play with the entry for standard deviation until the range of weights displayed appears to represent 95% of the mob under consideration. In figure 1 the indicated range (for 95% of the mob) is 441kg to 559kg. Changing the value for standard deviation will change this range.

For the data entered so far, the program has calculated that 16% of the total mob will be above the cut-off weight of 530kg at three and a half years old. This 16% of the mob (the leads) have an average weight of 546kg. The other 84% (the tails) have an average weight of 491kg. If they are expected to gain another 120kg over the next year this would give them an average turnoff weight at four and a half years old of about 611kg.

The next step in Splitsal calculates a net price for the leads mob (sold at 1st age) and tails mob (sold at 2nd age).

From the weights entered, and after entering; Price/Kg, Selling Costs (charged as a % of value or per head) and Transport Cost/Head the Net Price/Head is valued at $1485 and $1636 for the leads and tails respectively. Figure 2 illustrates the net price calculation.

Figure 2 - Net price calculations

For more detailed explanation on the principles behind the the Splitsal program and its assumptions go to Splitsal assumptions.