Breedcow+ Breedcow

Step 5 - Complete the Breedcow+ Breedcow worksheet

Once the Growth Path, AECalc, Prices, and Huscosts sheets have been completed, open the Breedcow worksheet, to complete the herd model and start to analyse the impact of alternative herd management strategies. Note that data can only be entered in the cells with a yellow background.

Section A: Calving and Death Rate Assumptions

File:Breedcow+ Breedcow Section A example.PNG

The Breedcow:Section A worksheet from Breedcow+

This section specifies the calves weaned as a proportion of cows retained and deaths for each class of livestock where relevant. Each age group in this table is labelled with the age at both the start and end of the year and the groupings used should be the same as applied in the AE Calc worksheet. Entries for female classes up to 13/14 years of age is possible.

1. Values can be entered directly into the cells opposite Calves weaned/cows Retained (%) however, for this version of Breedcow the PregTest macro is required to populate the Calves weaned/cows Retained (%) row.
2. Values can be entered into the first table to describe the reproductive performance for each age group of females.
3. Once values have been entered in these four rows, the Preg Test macro can be run and the Calves weaned/Cows retained values will be calculated and entered into the Calves weaned/cows Retained (%) row against the relevant age groups.
4. Other entries required in Section A are for the expected mortality rate for each age group of females and males (except herd bulls).

Notes

Identifying the weaning percentage for age groups

For the purpose of identifying the weaning rate for a group of cows, the age headings in Section A (for example the 2 to 3 age group) can be interpreted as if mating were at the first age (2) and weaning at roughly the second, even though physical weaning is likely to be at some point beyond the second age (3). The fact that the mating occurs towards the start of this period is the key issue. The outcome sought is an accurate estimate of the number of calves produced from this mating, though they are called “weaners” to allow for losses between birth and weaning.

Entering weaning percentages in the Breedcow worksheet

In the model, weaning rates are entered as the number of weaners produced as a proportion of the number of cows mated and kept and not just the cows mated. (Note: This is calculated automatically if the PregTest macro is used – see section A above).

This is done either manually or by using the PregTest macro and is different to the usually applied calculation of weaners produced from cows mated. Where weaning rates are being manually entered, some adjustments may have to be made to ensure that the correct number of weaners is produced by the herd being modelled.

For a breeding herd where all the cows are kept in the breeding herd for the entire period between mating and weaning, the weaning percentage will be based on the total number of cows mated. For example, if 100 cows are mated and all are kept with 70 calves weaned; the weaning rate for that group of cows in Section A will be 70 percent.

For a breeding herd where some cows are mated but sold after mating and prior to weaning, the weaning percentage will be calculated on the total number of cows mated and kept. For example, in a 100 cow breeder herd where 80 breeders are tested pregnant, non-pregnant cows are sold prior to weaning and 70 calves are weaned, the weaning rate from cows retained in Section A will be entered as 87.5 percent (70/80) AND the sales after mating (Section E) will have the value 20 percent inserted for that group of females. In this case the value shown at the bottom of Section E of the Breedcow+ worksheet for Weaners/all cows mated should show 70% - the value for the true calculation of weaning percentage.

The “true” weaning rate is the number of weaners produced from cows mated. The calculations behind the weaning percentage for each age group calculated as a percentage of the cows retained AND as a percentage of the total cows mated.

If the herd management strategy applied is to cull and sell cows based on pregnancy diagnosis prior to calving plus on the need to cull surplus cows – some pregnant cows may be sold prior to calving. In this case entries are required in the Breedcow worksheet for both weaning rate (based on the cows retained) in Section A and sales after mating (the empties) (in Section E).

If the data in the first table is entered in Section A, the PregTest macro can be used to make these entries simultaneously based on the percent pregnant, the proportion of pregnant females that lose a calf prior to weaning and the proportions of pregnant and empty cows sold.

The PregTest macro applies the values entered in the first table of the Breedcow worksheet. They are for:

• the expected conception rate for that group,
• the expected calf loss from pregnancy testing to weaning;
• the proportion of empty females sold from that joining age;
• the proportion of pregnant females sold from that joining age and whether the values calculated for weaning rate and sales are to be applied to later age joining groups

The PregTest macro is a quick way of estimating the reproduction efficiency of the breeder herd where the input data is available or can be estimated.

Once the PregTest Macro has been run, a summary of the performance of all the breeding females is provided on the PregTest tab.

The PregTest summary table provides the numbers and proportions for each class of females mated in the model. Data for the number empty at pregnancy testing, the number that were PTIC at pregnancy testing but then showed up without a weaner at weaning and the number remaining pregnant is shown.

Cows can also be sold unmated (Section E) but this will not affect weaning rate entries in Section A.

File:Breedcow+ Breedcow Section A PregTest Tab.PNG

The Preg Test tab from Breedcow+

Section B: Sale Prices

File:Breedcow+ Breedcow Section B.PNG

The Breedcow:Section B worksheet from Breedcow+

This should reflect the prices previously entered in the Prices worksheet. Changes should be made in the Prices worksheet, not in this section.

Ensure values are entered for all age and sex groups up to the maximum male turnoff and cow culling age. These prices are used to value sales and to place a capital value on the herd. Missing values cause the herd to be undervalued when asset values are being calculated.

Filling in values and sale weights in the AE Calc and Prices sheets beyond normal sale ages also allows some “what if” calculations to be undertaken on older male turnoff or a change to the mix of heifers and cull cows sold (which may require some being sold older or younger).

Sale age is specified as Weaners, 1, 2, 3 up to 14 years for female classes and up to five years (60 to 72 months old) for steer classes. Animals may be sold mid-year (18 months, 30 months) using the age labels 1, 2, 3, so long as the prices and sale used are correct for those mid-year ages. Ages in months for sale cattle are specified in AE Calc.

Section C: Steer and Bullock Herd Structure

File:Breedcow+ Breedcow Section C.PNG

The Breedcow:Section C worksheet from Breedcow+

This is used to configure the turnoff strategy for steers. Steer turnoff can either be “all at once” at one age or spread over a number of age groups.

The number of steers at the start of the year in the “0” group (weaners) is half the number of calves weaned. The number surviving to age 1 will be the opening number less deaths (from Section A), less any sales. Steer deaths are calculated on the opening number less sales.

Calving typically peaks about November / December in northern Australia and sales occur normally from May to June. It is therefore likely that the age of turnoff for steers is really at about 18 months, 30 months, 42 months or 54 months to fit in with seasonal growth patterns. When sale ages are part way into the designated year make sure that the prices specified are really for 18 months and 30 months, even though the labels say 1 and 2.

All herd numbers in the Breedcow worksheet are calculated to multiple decimal places, but displayed as integers. This level of precision is needed to achieve a balance in stable state, but can cause rounding errors in the display (for example, a worksheet may show 113 steers aged 3 when a calculation based on whole numbers may only indicate 112).

Splitting steer sales across age groups

Where male turnoff is to be only one age group, set all cells for Optional sales % to zero, and enter a value corresponding to the year of sale in the maximum male turnoff age cell. For example, if all steers are to be sold at three years old, a 3 needs to be entered as the maximum male turnoff age and zero’s need to be entered in the optional sales percent row.

Where steer sales will be undertaken at multiple ages, the oldest age group is sold by an entry in the maximum male turnoff age cell which corresponds with the maximum age of sale. Optional sales are shown as a percentage of the opening numbers under each age group in the Optional sales % row up until the maximum sale age previously entered.

For example, it is possible to specify a maximum turnoff age as 3 but sell the top 50 percent of the steers at 2. Where turnoff is based on animals achieving a particular weight before they can be sold and sales can occur over more than one year, estimates of the proportions of the herd likely to be sold in each year can be made in the Splitsal program. Splitsal will estimate average weights and prices for a group of sale cattle based on estimates of their current live weights and potential growth rates.

The impact on the average liveweight of a group of steers of selling the lead also needs to be considered when applying optional sales across a number of age groups. Selling the better steers out of a group of steers is generally expected to result in the average weights of the mob the following year being less than they would have been had the whole group been carried through. The Splitsal program can provide some help with this issue in that it can be used to identify the average weight of the “lead” and the average weight of the “tail” of a mob of steers.

Section D: Bull requirements

File:Breedcow+ Breedcow Section D.PNG

The Breedcow:Section C worksheet from Breedcow+

This section identifies the source and use of bulls for the breeding herd.

Entries required in this section are:

• bull/cow ratio (as a percentage of the total number of cows mated)
• number of bulls purchased per year (as a percentage of the bull herd)
• BYO bulls kept per year (as a percentage of the bull herd)
• bull deaths
• average bull purchase price

The number of bulls required is calculated using the total number of cows mated and will include cows that are sold after mating (e.g. sold empty after pregnancy diagnosis).

The replacement percentage or the rate at which new bulls enter the bull herd also needs to be specified. For example, if bulls are used in the breeding herd for five years and then culled, the replacement rate will be 20 percent. In the case of the example shown, the bulls are kept for five years. This means that the total breeding bull herd will be 17 bulls and 3 (or 20%) will be purchased each year to cover cull bulls sales (3) and deaths (0).

The replacement percentage can be split between purchased bulls and those bred on the property.

Therefore, if some weaners are kept by the property to be used as herd bulls, the percentages for purchased bulls and home bred bulls can be adjusted to show the source of herd bulls. The next figure shows 1 (5%) home bred bulls and 3 (15%) purchased bulls being used as replacements. The total replacement requirement of 20% per annum of total herd bulls is still met.

The price entered for purchased bulls should be the average landed price including freight and health checks not shown in the Huscosts worksheet.

Breed your own bulls retention

Retention of home bred Breed Your Own (BYO) bulls is allowed for in Section C (the steer and bullock herd structure table), although the decision entries are in the bull requirements table (Section D). The selection of BYO bulls will not show up in section C until relevant entries have been made in section D.

The model retains BYO bulls at branding and sets them aside from the available number of steers each year until they enter the bull herd in the two year old age group.

If home bred bulls are used in the breeding herd, the number retained in the 0, 1 and 2 age groups are shown in Section C as Number reserved as bulls, and the number in the 2 age group is then shown as Transfers to bull herd.

The value assigned to home bred bulls in the Breedcow worksheet is the value of two year old steers shown in Section B. The value shown for home bred bulls does not affect the calculation of the overall gross margin (except steer sale numbers are reduced) but it does affect the calculation of bull cost per calf weaned.

The sale price of cull bulls should already have been calculated and entered through the Prices worksheet.

Section E: Female herd structure

This section sets the sales of female livestock and the total size for the herd.

Section E generates the steady state herd around the female selling and heifer replacement policy. Sales are determined by setting the cow culling age and by making percentage entries for sales under each female age group. Any weaner heifers that are in excess of the requirement to maintain a steady state herd are sold automatically. The number of surplus weaner heifers is shown towards the top of Section E.

The figure shows the various points data can be entered in Section E. The order of entry is not critical and some adjustments are expected as data is entered:

1. Enter the weaner heifers to be retained. From this number, all other age groups are calculated after allowing for deaths, sales and removals through spaying.
2. Enter the age at first joining (1, 2 or 3, or at one of those ages plus some months) and the cow culling age. Both these entries should be made as integers, i.e. no decimal places. ##If the age at first joining is entered as 1, the number of heifers mated will be the number available at the start of the year less sales before mating less any heifers spayed or set aside from the breeding herd. The calves weaned from this heifer mating will depend on the weaning rate entry in Section A for the 1 to 2 age group. If there is no entry, the number of calves to be weaned will be nil. Note: for an age of mating of 1, the program allows for all or only a proportion of the heifers to be mated (e.g. if only half of the one year olds are to be mated, enter 50 percent in the percentage joined box beside the label). ##If the age at first joining is entered as 2, then both the cows mated row and the calves weaned row under the 1 to 2 age group will both show zero. The first group to show cows being mated and calves being weaned will be the 2 to 3 age group.
3. To the right of the Weaner heifers to be retained cell is a calculated prompt that shows the number of replacement weaner heifers required to maintain the herd in a steady state. Each time a change is made to the mating, selling or weaning herd parameters of the herd, or to the total number of adult equivalents required, this prompt will change. Set the number of weaner heifers to be retained to the value displayed in the prompt to ensure that the herd size in adult equivalents equals the number in Required herd size. The entry can be made quickly, from anywhere on the worksheet, by clicking on the AE button on the toolbar.
4. Enter the cow culling age (this also determines the maximum age of mating). Cows sold as a result of a culling age entry are sold unjoined after weaning the previous year’s calf. Thus culling at 13 means selling after joining at 12 to produce and wean the last calf at around 13. The female herd table will show zero opening cows for all ages after this culling age. A starting cow culling age of 13 can be entered and the macro Tools | Optimise Females Sales run once all culling and other breeder herd values have been entered to identify the optimal culling age for the breeding herd.
5. Enter required herd size in adult equivalents. Usually an informed guess when initially setting up a herd model, this entry will be refined as the sales from each group, the culling strategy and other herd performance parameters are entered. The relationship between the total number of cattle in each class and the total adult equivalents is best checked by looking at Section F: Total Cattle and Adult Equivalents.
6. Below the input cell for herd size in adult equivalents is a calculated cell showing surplus weaner heifers. This is total weaner heifers less the number required as replacements. These are shown as sales, but this number can be reduced to zero by shifting sales to other female age groups.

The number for “surplus” weaner heifers is an important part of the mechanism used to achieve a steady state herd. A negative “surplus” indicates that the weaning and death rates cannot support the modelled sales policy. The solution is to reduce the percentage of female sales or increase the cow culling age. A weaner heifer surplus of zero can be achieved by adjusting the percentage of yearling heifers sold to eliminate the original weaner heifer surplus.

1. All or some of the surplus heifers can also be set aside for later sale by putting a percentage in the Weaner % spayed cell. Therefore, surplus weaner heifers may be sold or they may be spayed and grown out. “Spaying” can be surgical, or it can mean keeping them unmated. If all surplus weaners are spayed or set aside, this figure can be set at 100 percent.

It is also possible to sell the heifer surplus as one year olds or as two year olds. To find the balance point at which yearling or two year old sales eliminate weaner heifer sales, use the menu command Tools | Heifers. Once the initial data entry in Section E has been made, the Breedcowplus program allows users to implement a number of management strategies for cows in each age group. Users can:

• make sales prior to mating as a percentage of the number cows at the start of the year
• spay or set aside cows prior to mating as a percentage of the cows at the start of the year
• make sales after mating as a percentage of the number of cows mated.

Once heifers and cows are spayed or set aside (i.e. not mated) they are transferred to the data block dealing with spayed cows and can then be sold in the next year (or two).

1. All sales and spay percentage entries, except for sales after mating, are applied to the number of cows or heifers available at the start of the year. Females sold after mating are included in the calculation of bulls required.

If sales after mating are based on pregnancy diagnosis, this can alter what is entered in Section A: Calving and Death Rate Assumptions, since the weaning percentage must be calculated as the weaning percentage on the number of cows mated and kept. Simultaneous entries for the weaning percentage on cows mated and kept, and sales after mating, can be made using the menu command Tools | PregTest. When surplus weaner heifer sales are reassigned to one or two year old groups using the Tools | Heifers command, they are entered as sales before mating. If the intention is to spay these heifers rather than sell them immediately, the sales before mating percentage can be moved to the cows spayed percentage. This can be done either manually or using the menu command Tools | Move sales before mating percentage to spay percentage. In practice, cull cows may be sold as they are identified or they may be set aside for later sale. Cows sold between mating and calving, whether pregnancy tested or otherwise, will be shown as sales after mating and will be included in the calculation of bull requirements. Cows that are identified as culls after mating but before calving, and then sold the following year, can be considered as sales before mating in that following year. Cows that failed to raise a calf can be sold before or after mating depending on when they are identified.

1. Spayed cows are sold off by entering a percentage against the carryover number. The default entry for all ages is 100 percent, on the assumption that all spays are sold in the year following spaying. Alternately, if heifers are for instance spayed as weaners and not sold until three years of age, sales from the 1 to 2 and 2 to 3 age groups will be 0% and sales from the 3 to 4 age group will be 100%. Part sales of a group, e.g. 50%, may also be entered.

The size of the overall herd can also be set based initially on the number of breeders required using the menu command Tools | Set Breeder Number. If using this command please identify the figure for total adult equivalents at Section F after the macro has been run and enter this as the required herd size in adult equivalents in Section E to rebalance the herd. Further readjustments to balance the herd will also be required as a final sales policy for female livestock is being developed.