Manage ruminants

CLEM.Activities.RuminantActivityManage

Performs a range of herd management tasks including adjusting the breeding herd to levels specified.

This description uses cows and calves as examples but is equally applicable to any ruminants (e.g. sheep with ewes and lambs).

The manage ruminants activity is used to undertake herd management actions to maintain the breeding herd at specified levels, and can also performs tasks such as managing a growing out herd of males and/or females including marking age or weight sales when met, castration, marking old male and/or female breeders for sale, and adjusting the initial herd size at the start of the simulation.

On-farm herd management is a complicated task that requires a variety of decisions based on the current and future state of the herd and farming system. While the multi-task nature of this activity is not consistent with the philosophy of CLEM, where each activity performs its single role, the complicated nature of interactions and implications of the tasks required means is it difficult for all users to perform these tasks as separate activities without a detailed understanding of the model and all implications of decisions. Therefore, we bundle a range of herd management tasks into this single activity where you can be assured the detailed nature of the order and decisions has been taken into account.

Customise the actions performed

It is acknowledged that this activity may contain too many tasks with limited customisation. For this reason, this activity now provides the ability to enable or disable each of the tasks outlined in this page and also provides means to provide additional user defined selection of individuals in addition to the default requirements of many tasks. This should provide much of the customisation required except for alternate timing of tasks which will have to be performed by other activities such as Mark ruminants for sale and Manage ruminant tag where timers and filtering can provide full customisation of tasks by experienced users. There is currently no alternate activity for undertaking the management of the male and female breeders or initialising the herd numbers at start up, so this activity remains the recommended approach.

The nature of the tasks to manage herd numbers means they are not performed every month. In large grazing enterprises these activities would be associated with an annual, or biannual, muster of all animals through the yards where they can be separated by class and appropriate actions and sales performed. For this reason, this activity requires a timer to determine when it is performed. This timer will apply to all tasks enabled in the instance of this activity. A ruminant move activity can be also be included to infer labour and financial costs in moving animals for this activity but is not necessary as this activity applies to the herd specified by its associated Ruminant activity groups.

If paddock grazing has been implemented this activity acts over the entire herd (of type specified) regardless of location, but will allow the pasture upon which to place particular groups to be specified.

It may take some detective work to identify the exact reasons why you are getting the herd dynamics simulated when all tasks are enabled.

This activity only marks individuals for sale where needed and requests purchases through the purchase list. It is the task of the Buy and sell ruminants activity to perform the sales and purchases. As this activity can modify the sales and purchases made by previous activities, any other activity occurring after the (Manage animals event) can modify these lists prior to sales and purchases.

The following section of will outline the general parameters of this activity.

An example simulation containing examples of many of the tasks performed in the Manage ruminants activity is provided in the CLEM_Sensibility_HerdManagement.apsimx simulation file. This provides guides for how to set up functionality as well as a sensibility test of the activities actions.

The following general activity parameters are available

This value determines an upper limit to the allowable number of female breeders after which the simulation will stop and report an error. This value is multiplied by the Maximum number of breeders kept to define the critical number and provides a safety mechanism for uncontrolled herd growth if losses through sales are missing or inadequate and the individual-based herd is growing too large and impacting system memory and CPU resources. If you need to allow a larger herd, you can change this value but changing sales and the Maximum number of breeders kept is the more appropriate method. Receiving this warning suggests the system is not functioning correctly.

This switch will determine whether the initial herd structure (defined in Ruminant initial cohorts) will be adjusted at the start of the simulation. This allows you to ensure the expected herd size is present at the start of the simulation based on the structure defined in Ruminant initial cohorts without the need to manually adjust the number of individuals in the initial cohorts. If the defined herd size of breeders is less than the specified Minimum number of female breeders to be kept the individuals in each cohort will be scaled up to achieve this minimum female breeder herd number. If the herd size of breeders from initial cohorts is greater than the Maximum number of female breeders kept the numbers will be scaled down to provide the Maximum number of female breeders kept.

This task is now performed prior to the herd being created and so there is no longer any reporting of adjusted individuals (e.g. flagged as FillInitialHerd or ReduceInitialHerd in the HerdChangeCondition) in the herd ledger report. Suckling individuals should scale with the number of breeders with a warning provided if insufficient female breeders are available for the sucklings present.

Any herd adjustment undertaken is reported as an Information message in the CLEM component and Summary (see Summary information).

The number of heifers in the herd is NOT taken into account to avoid the herd becoming greater than the set number of breeders when the heifers mature to breeders in the following months.

This switch will determine whether all non-breeding cohorts in the initial herd structure (defined in Ruminant initial cohorts) will be adjusted at the start of the simulation. The initial numbers in these cohorts will be adjusted at the same rate that female breeders are adjusted (see Adjust breeding females cohorts at start-up).

This switch will determine whether the initial herd of sires (defined in Ruminant initial cohorts) will be adjusted at the start of the simulation. This allows you to ensure the expected breeding sires are present at the start of the simulation. This task will obey any specified Maximum number of breeding sires keptsettings a either a set number of individuals or a proportion of the female breeder herd where the previously adjusted herd is used (see Adjust breeding females cohorts at start-up).

This task is now performed prior to the herd being created and so there is no longer any reporting of adjusted individuals (e.g. flagged as FillInitialHerd or ReduceInitialHerd in the HerdChangeCondition) in the herd ledger report.

This master switch determines whether Ruminant manage activity will undertake any female breeder tasks such as buying breeders, managing the herd to maximum breeders kept, and selling old breeders. Some tasks have switches that are nested below this switch. If turned off you will be responsible for managing the breeder numbers.

This switch will allow the Ruminant manage activity to arrange the sale of female breeders as necessary. If turned off you will be responsible for performing sales with a Mark ruminants for sale.

This switch will ensure Ruminant manage activity arranges the sale of breeding females based on Maximum female breeder age. If turned off you will be responsible for selling old breeders with a Mark ruminants for sale. This task requires Manage female breeder numbers and Perform female destocking tasksto be enabled.

This switch will allow the Ruminant manage activity to arrange the purchase of female breeders as necessary. If turned off you will be responsible for performing purchases with a Arrange ruminant purchase.

This master switch determines whether Ruminant manage activity will undertake any male (sire) breeder tasks such as buying sires, managing the number of sires, and selling sires. Some tasks have switches that are nested below this switch. If turned off you will be responsible for managing the sires.

This switch will allow the Ruminant manage activity to arrange the sale of male breeders (sires) as necessary. If turned off you will be responsible for performing sales with a Mark ruminants for sale.

This switch will allow the Ruminant manage activity to arrange the purchase of male breeders (sires) as necessary. If turned off you will be responsible for performing purchases with a Arrange ruminant purchase.

This switch will ensure Ruminant manage activity arranges the sale of sires based on Maximum sire age. If turned off you will be responsible for selling old breeders with a Mark ruminants for sale. This task requires Manage male breeder numbers and Perform male destocking tasks to be enabled.

This parameter will determine what action is taken if there are insufficient resources to perform this activity.

You can report an error and stop the simulation, skip this activity or use the resources available. See What to do when resources are limiting

This activity makes a number of assumptions when selecting individuals from the herd, sale list and purchase list. It may be that you need greater control over the order and individuals sold such as preferring to sell older breeders and maintain the younger breeders. This can be achieved by adding any number of Ruminant groups below this activity with appropriate Identifier set for each task (See all Individuals managed sections below). If Ruminant groups with the appropriate Identifier are present the model will use each of these filter groups to further reduce the individuals needed for the task (See all Individuals managed sections below for a full list of filter conditions for each task) the in the order specified. This approach means you don't have to worry about the exact filters required for the task and can assume your filters will act upon the required list. It is worth noting what the requirements of any task are (see tasks below) to ensure you filters do not conflict and result in no individuals selected.

When provided, only the custom filters will be applied upon the planned list of individuals. This allows you to specify individual groups in order until the target number is achieved or stop if insufficient individuals were located. Adding a a Ruminant group with no filters ("All individuals") last in your list provides a "fall back" as a final attempt considering all possible individuals for the task (minus those you already acted upon by custom filters as they are unlikely to meet the criteria once acted upon).

Restricted removal example

Assume we want to remove only the ten oldest breeders and then all pre breeders in an attempt to meet the required herd reduction when greater than the maximum number of breeders were present. To achieve this we would add two Ruminant groups each with the Identifier set to RemoveBreedersFromHerd below this activity as children.

IsBreederSort Age descendingTake 10 individuals

IsPreBreeder

This will attempt to remove these subsets of the target individuals (see sections below) and if insufficient individuals removed, will stop

Modified removal example

Assume we want to only remove 75 percent of the old breeders from the herd. To achieve this we would add a Ruminant group with the Identifier set to RemoveOldFemalesFromHerd below this activity as a child.

Sort Age descending Take Proportion 0.75

This filter is not restricting and will sort the individuals found by age descending and return 75% of the individuals found not for sale, and Female with a age greater than the maximum breeder age. The full complement of 75% will only be taken if the required target is greater than or equal to the calculated number.

Preferred removal example

Assume as our priority we want to remove any underweight breeders before considered the remainder of individuals to reduce breeders. To achieve this we would add two Ruminant groups with the Identifier set to RemoveBreedersFromHerd below this activity as a child.

ProportionOfHighWeight < 0.75

The first filter will select all underweight individuals (current weight is less than 75% of maximum weight achieved) from the breeders and pre-breeders that will become a breeder in the next year (see herd sale conditions below) to remove. Note: As this filter does not specify an order the individuals will be taken in the order they appear in the herd, so usually oldest to youngest as an outcome of when they are added. Therefore it is recommended that you apply sort filters where a preferred order is required as this has not been assumed in the base filters for tasks unless critical.

If the initial filter was unable to provide the required individual, the second empty filter will allow the base filter requirement to be run again with all possible individuals, in this case the individuals with a current weight to high weight achieved proportion greater than or equal to 75%.

* 50% of high weight is usually set as the mortality cut-off.

These custom groups also specify both the removal of individuals as well as selection if individuals when individuals should be kept. This allows different rules for the removal or retention of individuals as they may be ordered in opposite directions for based on value (e.g. condition or genetics)

The following components will add additional functionality to this activity

This activity provides the following identifiers: Herd size before activityAdjust - new grow out malesAdjust - new grow out femalesDestock - grow out malesDestock - grow out femalesDestock - old siresDestock - old female breedersDestock - excess siresDestock - excess female breedersStock - female breeder purchasesandStock - sire purchases

This activity provides the following units for components: fixedandper head

Any Labour requirement will include labour allocation to perform this activity based on any specified identifiers and units and may limit the outcomes if supported and OnPartialResourcesAvailableAction set to UseAvailableWithImplications

Any Activity fee will include financial costs based on any specified identifiers and units and may limit the outcomes if supported and OnPartialResourcesAvailableAction set to UseAvailableWithImplications

This activity will occur in every time-step unless timers are used to restrict this activity (see Using timers).

This activity will obey all Ruminant activity group in the simulation tree at and above it's location.

Only one instance of this component is permitted in each Activity.

This activity is performed during the Animal manage event of the setup and time-step events after all feeding, growth, births and deaths (and all general activities) have been performed. This ensures this activity has the ability to modify the sales and purchases set by other activities (performed in the Get resources required event) and that all management happens before buying, selling and trucking decisions are made, and it's sales and purchases can be modified by future destock activities.

While the model defines the order of events in a single time-step to ensure processes happen in the appropriate order, the model cannot make decisions about the timing of events between time steps. For this reason the user should be aware that some undesired outcomes may arise as a result of the timing specified. For example, if a Manage ruminants activity determined that additional female breeders were required it would add these to the purchases list. If the Buy and sell ruminants activity was performed in that time step, then the purchases will be made subject to available labour and financial resources. A Perform predictive seasonal stocking activity may be performed the next time-step (month) that determines that there is insufficient pasture and the herd needs to be reduced. In reality, the manager would have foreseen this lack of pasture and not made the outlay of new breeders at that time, only to have to reduce the herd by sales the following month.

This situation can be avoided in a number of ways. First, you could ensure that the Manage ruminants and Perform predictive seasonal stocking are performed in the same time step (i.e. same month) as the activities will manage the adjustment of purchase and sales accordingly. The second option would be not to perform Buy and sell ruminants every month but only after all the herd management decisions had been made. This of course would stop the monthly sale of steers that had met age or weight for sale, but better reflects the organisation of trucking in specified months. You may also consider turning off the selling options in this activity and using the Mark ruminants for sale activity and perform more detailed handling of stock sales.

 

An example of modifying the sale status of animals is the destocking herd activity that might need to reduce the herd after this activity has already added new individuals to the purchase pool and identified individuals for sale. The destocking activity could clear the purchase list and account for animals that are flagged for sale before determining the number of individuals to destock. This is possible because of the order these activities are processed (all general activities, manage ruminants activity, destock activities), regardless of their position in the simulation tree.

The following status values apply to this activity and are shown in Activities performed report only if each task is enabled:

blank The activity was not considered in this time-step
not needed No herd management was required
incomplete Unable to reduce herd to required levels for sires or breeders
success

One of the following occurred:

  • Males reaching age or weight were marked for sale (if enabled)
  • Breeding sires were ordered or marked for sale
  • Old sires were marked for sale (if enabled)
  • Excess breeders were marked for sale
  • Young females were marked for sale (if enabled)
  • Breeders were required
  • Old breeders were marked for sale (if enabled)
partial One of the tasks above could not be fully completed

 

Ruminant Manage Tasks

The following section outlines the various tasks provided by this activity.

This task involves arranging for purchases and sales of breeders and pre-breeders in order to maintain the breeding herd at the specified levels.

The following activity parameters relate to this task

Parameters in the Breeding females sub category of Herd Size category in the property tab.

This switch determines whether this instance of the activity will perform the actions needed to maintain the number of female breeders through sales, purchases and within herd replacement.

This sets the maximum number of breeders to be maintained. A herd with breeders in excess of this amount will result in the sales (see details).

There is currently no means of having this calculated based on stocking rates or pasture utilisation. This should be calculated at set up.

Requires Manage female breeder numbers and either Perform female stocking or Perform female destocking

The minimum number of breeders kept will determine the number that within herd replacement and breeder purchases will try and attain. The model will assume natural replacement of breeders from births to grow the herd from minimum number of breeders kept to maximum number of breeders kept.

If minimum number of breeders kept is greater than maximum number of breeders kept the maximum kept will automatically be set to the minimum. This will result in both herd replacement and purchases being used to build herd to the designated maximum herd size. The reason for this functionality is to allow setting the value maximum number of breeders kept as a factor in multi-simulation experiments to set the upper limit of the breeders. This is required to avoid having to set two values at once and assumes the minimum number of breeders kept is set to be an unused value greater than the largest maximum number of breeders kept.

Requires Manage female breeder numbers and either Perform female stocking or Perform female destocking

Parameters in the Breeding females sub category of Restock category in the property tab.

This restricts the number of breeders that can be purchased in a single purchase to avoid large transactions when restocking large herds.

Set this value to 0 (zero) to prevent the purchase of breeders and rely entirely replacing the breeders from young individuals.

Alternatively , this can be achieved by setting Minimum number of female breeders to be kept to 0.

Requires Manage female breeder numbers and Perform female stocking

If this switch is on (true) the pregnant females marked for sale as MaxAgeSale will be returned to the breeding herd when additional females are required. This highlights the value of the offspring in increasing the herd. This action is last in the order of attempts to increase the breeder number and happens after any purchases and therefore, will only be used when additional breeders are required and not using purchases or there are insufficient funds to purchase breeders, and pregnant individuals of maximum age to be kept have been flagged for sale.

Any pregnant maximum age breeders retained will likely be sold the next year as maximum age sales will not be considered for breeding in Controlled mating. In uncontrolled mating simulations, the model may retain these old breeders as long as they continue to conceive and are providing required offspring to increase the breeder herd.

Requires Manage female breeder numbers and Perform female stocking

Replacement breeders are individuals that have been weaned, but not attained breeding age and weight criteria (Class = PreBreeder) but have been identified as needed to replace breeders to maintain the herd size. These individuals have special treatment in herd management decisions in this activity. If this switch is on (true) any individuals flagged as replacement breeders can be removed from the individuals marked for sale to maintain the breeding herd. These PreBreeders are likely to become breeders in the next year before this activity is performed again and this task occurs late in the decision process to restock the herd.

Requires Manage female breeder numbers and Perform female stocking

The following components are required if this task is performed and female stocking is enabled.

The details of purchased females (breeders) are provided by adding Specify ruminant components below this activity. Any number of these components can be added with the proportion property determining the numbers purchased form each group as a proportion of the total needed.

You must provide at least one Specify ruminant specifying an idividual that meets the breeder criteria (sex, age and weight)

The mode will produce validation errors if any these individuals are not defined, or if a Specify ruminant component does not represent either breeders or sires.

The group of individuals selected for each task can often be further filtered to work with specific subsets using Custom filtering of individuals.

The number of breeders in the herd is allowed to increase to minimum number of breeders kept by purchases and natural herd reproduction with only inputs from births able to contribute up to the maximum number of breeders kept, above which the herd will be reduced through sales. Setting these two values the same will result in management trying to keep the herd at this level by both births and purchases.

An excess or deficit of breeders is next calculated by comparing the breeder herd size to the maximum number of breeders kept and also accounting for mortality in period before the next management to avoid unnecessary selling

Requires Manage female breeder numbers Perform female destocking

Any excess in the number of breeders (above maximum number of breeders kept taking into account upcoming deaths) needs to be reduced. The individuals to be sold can be identified in two ways and are removed in the following order:

1. Remove suitable individuals from the future purchase list to avoid purchases

This task will be performed on individuals meeting the following filter rules

Female Purchase list IsBreeder

You can further customise this selection by adding Ruminant groups with the identifier RemoveBreedersFromPurchases

2. Remove individuals from the herd not marked for sale. This will include breeders and any pre-breeder that will reach breeding age in the next 12 months.

This task will be performed on individuals meeting the following filter rules

Female Not for sale [IsBreeder or <12 months before becoming a breeder] ordered by age descending.

You can further customise this selection by adding Ruminant groups with the identifier RemoveBreedersFromHerd. This allow you to order the priority between selling prebreeders and breeders in the herd as well as specifying the condition of breeders to consider in order.

3. Remove excess replacement breeders previously identified

This task will be performed on individuals meeting the following filter rules

FemaleNot for sale [Replacement breeder

You can further customise this selection by adding Ruminant groups with the identifier RemoveFemaleReplcamentBreeders. This allow you to order the priority for removing unneeded replacement breeders.

Requires Manage female breeder numbers Perform female stocking

The breeder herd needs to be increased when below maximum number of breeders kept. Purchases and births will be used up until minimum number of breeders kept with only births used between minimum number of breeders kept and maximum number of breeders kept. No purchases will be allowed if the pasture biomass of the destination pasture (GrazeFoodStore (paddock) to place purchased breeders in) is below a set limit (Minimum pasture (kg/ha) before restocking if placed in paddock) to ensure restocking is halted until pasture begins to recover after drought spells. The required individuals are obtained from the following pools in the order specified:

1. Sale herd. Remove suitable breeders from the sale herd (not MaxAgeSale representing the old breeders).

This task will be performed on individuals meeting the following filter rules

FemaleReady for sale [IsBreeder or Ready to breed in next 12 months] Not marked MaxAgeSale

You can further customise this selection by adding Ruminant groups with the identifier SelectBreedersFromSales

2. Grow-out herd maturing within 12 months. Check for any suitable young females in the grow out population (if turned on) and move to breeder location marked as replacement breeders until reaching breeding age.

This task will be performed on individuals meeting the following filter rules

Female [IsBreeder or Ready to breed in next 12 months] Not marked for sale Grow out individual

You can further customise this selection by adding Ruminant groups with the identifier SelectYoungFemalesFromGrowOut

3. If purchases are allowed (Maximum proportion of breeders in single purchase > 0) and while finance resources permit, buy breeders based on the specification provided by Specify ruminant components provided. Providing a number of these components with different ages will ensure these females are distributed across age classes to avoid large pulses of same age individuals. Like male breeders the number of female breeders purchased in a single transaction (typically after drought where the herd has declined) can be limited using Proportion of maximum breeders in single purchase.

There are no more options to get more breeders, so the replacement breeder status of individuals is next updated.

If there are more replacement breeders than the number of breeders still required the replacement breeders will be reduced

This task will be performed on individuals meeting the following filter rules

FemaleNot for sale [Replacement breeder

You can further customise this selection by adding Ruminant groups with the identifier RemoveFemaleReplacementBreeders. This allow you to order the priority for removing unneeded replacement breeders.

If more breeders are still required

4. Select younger individuals in Grow out herd that will mature in next 12 months and bring to breeder paddock and mark as replacement breeder.

This task will be performed on individuals meeting the following filter rules

Female Marked as GrowOutMatures in next 12 months

You can further customise this selection by adding Ruminant groups with the identifier SelectYoungFemalesFromGrowOut

5. Consider younger individuals that will mature in next 12 months in sale herd to mark as mark as replacement breeders. This option will only be selected if purchases are not enabled and so replacement from the herd is the only option and therefore these individuals must be selected even if there is a gap before breeders are present. These individuals are chosen after the grow out herd as there must have been a reason for their sale.

This task will be performed on individuals meeting the following filter rules

Female Ready for saleMatures in next 12 months

You can further customise this selection by adding Ruminant groups with the identifier SelectYoungFemalesFromSales

6. Consider youngest individuals in sale herd to mark as mark as replacement breeders. This option will only be selected if purchases are not enabled and so replacement from the herd is the only option and therefore these individuals must be selected even if there is a gap before breeders are present. These individuals are chosen after the grow out herd as there must have been a reason for their sale.

This task will be performed on individuals meeting the following filter rules

FemaleReady for saleAge descending

You can further customise this selection by adding Ruminant groups with the identifier SelectYoungFemalesFromSales

7. Consider younger individuals in growing out herd to mark as mark as replacement breeders. This option will only be selected if purchases are not enabled and so replacement from the herd is the only option and therefore these individuals must be selected even if there is a gap before breeders are present. These individuals are chosen after the grow out herd as there must have been a reason for their sale.

This task will be performed on individuals meeting the following filter rules

Female Marked as GrowOutAge descending

You can further customise this selection by adding Ruminant groups with the identifier SelectYoungFemalesFromGrowOut

8. Consider unweaned females as replacement breeders.

This task will be performed on individuals meeting the following filter rules

FemaleUnweanedAge descending

You cannot further customise this selection

9. If Retain pregnant Maximum Age individuals if short of breeders is enabled, then remove any individuals from the sale herd flagged as BreederAgeSale (all other breeders, or future breeders, in sale herd should already have been considered) that are pregnant as the offspring is valuable for maintaining the herd.

This task will be performed on individuals meeting the following filter rules

Female Ready for sale IsPregnant

You cannot further customise this selection

 

Any shortfall still remaining will be present until the next herd management activity. The replacement breeders are adjusted each time this activity is considered and purchases will occur, if allowed, before replacement breeders are considered.

The number of months for young females to mature after weaning may result in multiple instances of this activity being performed before they are considered mature and suitable as replacement breeders or sires. This activity can mark individual PreBreeders as ReplacementBreeders ensuring they will not be sold, but are being held until they mature and enter the breeder cohorts. This will ensure that required future breeders are maintained for the period of time for maturity in combination with any growing out actions, with subsequent sales.

Previous versions of the model considered all weaned females suitable for breeding in the following year with an early age of maturity, but this cannot be assumed for all breeds and species. For this reason this component will identify individuals as future breeders ,and keep them from being grown out or sold, to replace breeders and sires as they age. Ideally this would be performed prior to the old breeders reaching the maximum age and being sold. The aim for a small holder system would be to keep the number of individuals to a minimum during the growth of young individuals before maturity.

Females may be considered too old to be kept in the breeding herd. This task performs the marking of old breeders for sale.

The following activity parameters relate to this task

Parameters in the Breeding females sub category of Destock category in the property tab.

This switch will determine if this activity marks females for sale when greater than the Maximum female breeder age (months).

If not on, the user must use Mark ruminants for sale activity to manage old breeders.

Requires Manage female breeder numbers Perform female destocking

The maximum age (months) for breeders before being culled or sold.

Requires Manage female breeder numbers Perform female destocking Mark old breeders for sale

The group of individuals selected for each task can often be further filtered to work with specific subsets using Custom filtering of individuals.

If Mark old breeders for sale is selected, this activity will flag all individuals over a specified age (Maximum breeder age for sale. These individuals will not be considered as present in any other calculations to maintain herd size prior to being sold, and this assumes there will be no future problems with the sales such as financial or trucking restrictions.

This task will be performed on individuals meeting the following filter rules

Female Age >= Maximum breeder age Not for sale

You can further customise this selection by adding Ruminant groups with the identifier RemoveOldBreedersFromHerd

This section describes the steps taken to manage male breeder numbers in your herd.

The following activity parameters relate to this task

Parameters in the Breeding males sub category of Herd Size category in the property tab.

This switch determines whether this instance of the activity will perform the actions needed to maintain the number of male breeders (sires) through sales, purchases and within herd replacement.

This task will manage the breeding males considered for breeding purposes such as high value males purchased and maintained in the herd. Controlled mating can occur without breeding males in the herd as it assumes the hiring of sires or access to artificial insemination and so you may not need to include breeding sires.

Some herd management may allow uncastrated males to mature to breeding age which will breed with female breeders. These individuals class is WildBreeder. Care should be taken to avoid these individuals mixing with females if using uncontrolled mating unless replacing breeding sires from within the population.

This sets the desired number of breeding males kept.

The actual number of breeding males kept will be set if this value is greater than or equal to 1.

If this value if provided as a proportion (0<x<1), then the number of breeding males will be calculated as a that proportion of the maximum breeding females kept.

A value of zero will not keep breeder males in the herd. This is used if you are relying on controlled mating including artificial insemination.

Wild breeders are not considered in these calculations.

Requires Manage male breeder numbers and Perform male destocking or Perform male stocking

Parameters in the Breeding males sub category of Restock category in the property tab.

This switch determines whether sires can be replaced from births.

Requires Manage male breeder numbers Perform male stocking

As purchasing sires can be expensive, there is no need to maintain the full complement of sires when the breeding herd is below the maximum number of breeders kept. This switch enables the number of sires considered for purchase to be based on the product of the current proportion of breeders to the maximum breeder herd and the specified maximum number of sires kept for the full herd. By the time the full female breeder herd is present the full complement of males breeders should also be present if this approach is selected.

Requires Manage male breeder numbers Perform male stocking

This restricts the number of sires that can be purchased in a single purchase to avoid large transactions.

Requires Manage male breeder numbers Perform male stocking

Replacement breeders are individuals that have been weaned, but not attained breeding age and weight criteria (Class = PreBreeder) but have been identified as needed to replace breeders to maintain the herd size. These individuals have special treatment in herd management decisions in this activity. If this switch is on (true) any individuals flagged as replacement breeders can be removed from the individuals marked for sale to maintain the sires. These PreBreeders are likely to become breeders in the next year before this activity is performed again and this task occurs late in the decision process to restock the herd.

Requires Manage male breeder numbers Perform male stocking

The following components are required if this task is performed

The details of purchased males (sires) are provided by adding Specify ruminant components below this activity. Any number of these components can be added with the proportion property determining the numbers purchased form each group based on total number required.

You must provide at least one Specify ruminant specifying a sire if purchasing is required (see MaximumProportionBreedersPerPurchase and MaximumSiresPerPurchase above to enable purchasing)

The mode will produce validation errors if any of these individuals are not defined, or if a Specify ruminant component does not represent either breeders or sires.

The group of individuals selected for each task can often be further filtered to work with specific subsets using Custom filtering of individuals.

The number of male breeders (sires) in the herd is either specified, set as a proportion of the maximum female breeder herd, or tuned off, by setting the maximum number of male breeders kept to a value greater than or equal to one, a value between zero and one, or zero respectively. The current number of breeding males is compared with the specified value and adjusted accordingly. Breeding sires are either obtained from the herd if possible (allow male breeder replacement from herd) or purchased with specified limits on the number allowed in a single purchase or linked to the current breeder herd as a proportion of the maximum herd allowed to reduce expensive outlays of breeding sires. By the time the full female breeder herd is present the full compliment of males breeders should also be present if this approach is selected.

Males will not be purchased if the pasture biomass (Minimum pasture (kg/ha) before restocking if placed in paddock) of the destination pasture (GrazeFoodStore (paddock) to place purchased sires in) is below a set limit to ensure restocking is halted until pasture begins to recover after drought spells.

The Sire attribute (IsSire) is reserved to identify individuals of higher breeding potential that may have been purchased at higher prices or command different management practices.

Unmanaged breeding males can be present in the herd and cause breeding (when uncontrolled mating is used). If castration is turned off and there is no sale of grow-out males by age or weight (or sale age/weight is greater than maturity) all males born will reach breeding age and be able to breed while present. These individuals are categorised as WildBreeder as they have not been purchased or selected from the herd to be breeding males (sires). A warning will appear in the Descriptive Summary if settings allow this to occur.

Requires Manage male breeder numbers Perform male stocking

When required Sires are provided from the following sources in order

1. Sale herd. Sires will be removed form the sale herd.

This task will be performed on individuals meeting the following filter rules

MaleReady for saleNot MaxAgeSaleIsSire

You can further customise this selection by adding Ruminant groups with the identifier SelectSiresFromSales

2. Sale herd. Young males (uncastrated) will be removed form the sale herd. Young males will be marked as replacement breeder and not considered for sale through age weight sales until reaching breeder age. This approach assumes if Allow sire replacement from herd is enabled this is the preferred approach over purchasing expensive sires, even if there is a lag before breeding. This could be disabled by adding a ruminant group custom filter Take 0, to return no individuals.

Future addition. It would be useful to allow filters have conditions such as perform when number of sires in the herd is less than 1, so no replacements would be taken if a Sire was present. But this is currently NOT implemented.

This task will be performed on individuals meeting the following filter rules

Male Ready for sale Not MaxAgeSale Weaned Not castrated Ready to breed in next 12 months

You can further customise this selection by adding Ruminant groups with the identifier SelectYoungMalesFromSales

3. Grow out herd. Select young (uncastrated) males from the grow out herd. Young males will be marked as replacement breeder and not considered for sale through age weight sales until reaching breeder age.

This task will be performed on individuals meeting the following filter rules

Male Not for sale [IsSire or Replacement breeder] Sort by class descending

You can further customise this selection by adding Ruminant groups with the identifier SelectYoungMalesFromGrowOut

4. If Retain replacement sires from sale herd if short of sires is enabled any sale herd in the following months will be monitored for sales for suitable individuals each time-step to ensure weaners are not sold if they will be replacement sires.

Requires Manage male breeder numbers Perform male destocking

When in excess Sires are removed in the following order

1. Purchases. Sires and young males (uncastrated if replacement breeding enabled) will be removed from the purchase herd.

This task will be performed on individuals meeting the following filter rules

Male Purchase list IsSire

You can further customise this selection by adding Ruminant groups with the identifier RemoveSiresFromPurchases

2. Remove sires and any replacement sires. The test for sire and replacement breeder ensures they are not castrated and sorting by class descending ensures overall Replacement are considered before Sire, but this can be modified by the custom filters.

This task will be performed on individuals meeting the following filter rules

Male Not for sale [IsSire or Replacement breeder] Sort by class descending

You can further customise this selection by adding Ruminant groups with the identifier RemoveSiresFromHerd

Sires may be considered too old to be kept for mating in the herd. This task performs the marking of old sires for sale.

The following activity parameters relate to this task

Parameters in the Breeding males sub category of Destock category in the property tab.

This switch will determine if this activity marks sires for sale when greater than the Maximum sire age (months) before removal.

If not on, the user must use Mark ruminants for sale activity to manage old breeders.

Requires Manage male breeder numbers Perform male destocking

The maximum age (months) for sires before being marked for sale.

Requires Manage male breeder numbers Perform male destocking Mark old sires for sale

The group of individuals selected for each task can often be further filtered to work with specific subsets using Custom filtering of individuals.

If Mark old sires for sale are selected, this activity will flag all individual sires over a specified age (Maximum sire age) for sale. These individuals will not be considered as present in the following calculations to maintain herd size prior to being sold, and this assumes there will be no problems with the sales such as financial or trucking restrictions.

This task will be performed on individuals meeting the following filter rules

Male Age >= Maximum sire age Not for sale IsSire

You can further customise this selection by adding Ruminant groups with the identifier RemoveOldSiresFromHerd

Often young individuals will be grown on pasture or fodder for a period of time after weaning to obtain the best prices or sale criteria (e.g. steers). Alternatively, you may wish to sell all individuals immediately once weaned to save on the cost of feed and obtain income. This section enables you to define the growing out and selling of immature individuals (once weaned) from the herd.

This approach is also used for maintaining small herds in household farms to ensure feeding is kept to a minimum and a small herd (including one breeder) is maintained. For example, all young animals could be sold when 12 months old (approximately 3 months after weaning), or animals could be weaned early and sold younger to access more milk production.

This task can also be performed using a Manage ruminant tag activity and associated timers and Ruminant group for selecting individuals. A tag with label "GrowOut" is used to identify an individual as belonging to the growing out herd.

The marking of suitable individuals for sale is only undertaken when this activity is performed. To sell grow-out individuals in other months you will need to add a Mark ruminants for sale activity filtering for individuals with a tag "GrowOut" and the specified weight and or age criteria.

The following activity parameters relate to this task

Parameters in the Males sub category of Grow out herd category in the property tab.

This switch (when true) will perform all actions needed to manage the growing out of young males including selection of individuals and moving to the correct pasture (paddock).

This activity will also check to determine whether each male in the grow out herd has reached a specified age or weight and if so mark them for sale with the AgeWeightSale flag. The following parameters are used to define this action.

This switch will ensure young males are castrated when selected for growing out until age or weight achieved. See Perform castration of young males

This switch will allow this activity to mark grow out males for sale when they reach age or weight criteria.

The minimum age (months) for males to be sold.

Requires Perform growing out of young males Mark grow out males for sale

The minimum weight (kg) for males to be sold.

Requires Perform growing out of young males Mark grow out males for sale

Animals are tagged with a label "Grow out", and moved to specified pasture if needed. Sales (when Mark grow out males for sale enabled) can either every time-step (Continuous male sales), or whenever this activity is performed. For males, any individual that is weaned and not a breeding sire is marked.

This activity next marks growing out individuals for sale (AgeWeightSale) if they are greater than or equal two the specified age or weight for sale (Male selling age or Male selling weight). Any individuals not meeting the conditions are left until this is next checked by this activity.

This task will be performed on individuals meeting the following filter rules

Male Weaned Not replacement breeder Not Sire

You can further customise this selection by adding Ruminant groups with the identifier SelectMalesForGrowOut

This selection includes all animals in the herd including those currently marked for sale. This will ensure that individuals meeting the criteria are marked for growing out and have a grow out location set should the sales not be successful forcing the sale individuals to be returned to the herd. If sold this allocation to growing out won't have an affect unless reporting on grow out sales.

Rather than selling excess pre-breeder females when determined, females can also be grown to a specified age or weight before selling. As these individuals are not castrated like males, they also provide an on-farm pool of breeders when required prior to sales. This section enables you to define the growing out and selling of excess immature female individuals (once weaned) from the herd.

This task can also be performed using a Manage ruminant tag activity and associated timers and Ruminant group for selecting individuals. A tag with label "GrowOut" is used to identify an individual as belonging to the growing out herd.

The marking of suitable individuals for sale is only undertaken when this activity is performed. To sell grow-out individuals in other months you will need to add a Mark ruminants for sale activity filtering for individuals with a tag "GrowOut" and the specified weight and or age criteria.

The following activity parameters relate to this task

Parameters in the Females sub category of Grow out herd category in the property tab.

This switch (when true) will perform all actions needed to manage the growing out of young females including selection of individuals and moving to the correct pasture (paddock).

This activity will also check to determine whether each female in the grow out herd has reached a specified age or weight and if so mark them for sale with the AgeWeightSale flag. The following parameters are used to define this action.

This switch will allow this activity to mark grow out females for sale when they reach age or weight criteria.

Requires Perform growing out of young females Mark grow out females for sale

The minimum age (months) for grow out females to be sold.

Requires Perform growing out of young females Mark grow out females for sale

The minimum weight (kg) for grow out females to be sold.

Requires Perform growing out of young females Mark grow out females for sale

Animals are tagged with a label "Grow out", and moved to specified pasture if needed. Sales (when Mark grow out males for sale enabled) can either either every time-step (Continuous male sales), or whenever this activity is performed. For males, any individual that is weaned and not a breeding sire is marked, while for females (Mark young females for sale with age/weight males) any individual that is weaned and less than the minimum age at first mating is identified as growing out and moved to specified pasture.

This activity next marks growing out individuals for sale (AgeWeightSale) if they are greater than or equal two the specified age or weight for sale (Male selling age or Male selling weight). Any individuals not meeting the conditions are left until this is next checked by this activity.

This task will be performed on individuals meeting the following filter rules

Female Not for sale IsPreBreeder Not replacement breeder

You can further customise this selection by adding Ruminant groups with the identifier SelectMalesForGrowOut

This selection includes all animals in the herd including those currently marked for sale. This will ensure that individuals meeting the criteria are marked for growing out and have a grow out location set should the sales not be successful forcing the sale individuals to be returned to the herd. If sold this allocation to growing out won't have an affect unless reporting on grow out sales.

Castration of young males is a management task used to increase growth rates of young males prior to sale and avoid breeding and behaviours of young bulls.

Castrated males (e.g. steers and bullocks) have a lower maintenance energy requirement than a non-castrated males of the same size by a factor of 0.87 (Nutrient requirements of domesticated ruminants, 2007) while having the same standard reference weight and maximum size. The lower maintenance energy demand means a greater proportion of the energy obtained from intake is used for growth, resulting in faster growth rates than non-castrated breeders of the same size.

Castration in CLEM is achieved by adding a tag with label "Castrated" to an individual. You can use the Male Ruminant property IsCastrated or Attribute.Exists ("Castrated") methods in filters to select this group of individuals for management. You can also manually perform castration on any males using the Manage ruminant tag activity and assigning the tag labelled "Castrated" (see warning below).

Care is required when performing manual castration as Manage ruminant tag will not prevent castration of breeding sires, after which they will not be available for breeding. When doing castration with Manage ruminant tag (add Castrated tag) ensure filters do not select sires by adding a Filter by property with settings IsSire = False to the selection filters. You should also consider ignoring unweaned (IsWeaned = False) and replacement sires (IsReplacementBreeder = False) to ensure you do not affect other important processes by castration. Care should be taken (or use castrate in this activity only) if you are replacing breeding males from the herd as castration will not allow sires to be replaced in the same time-step. If you do not include a male based filter such as IsSire you should also include Sex = Male to avoid unneeded tags being added to female ruminants.

The following activity parameters relate to this task

Parameters in the Breeding males sub category of Destock category in the property tab.

This switch will ensure the young grow out males are castrated (e.g. to provide steers or bullocks) when first defined as "GrowOut" individuals. This procedure is permanent after this time-step. This activity does have the ability to assign some young males to be replacement sires prior to castration.

Requires Perform growing out of young males

As animals are added to the herd in this activity, you may need to identify the pasture (paddock) upon which they are placed. In order to be able to separate breeders from sires (when uncontrolled, natural mating is implement), the pasture for each group is provided. Pasture levels are checked before individuals are added through purchases, unless individuals are being moved for growing out.

The following activity parameters relate to this task

Parameters in the Pasture sub category of Restock and Grow out herd categories in the property tab.

The minimum biomass of pasture (kg/ha) before restocking is permitted if animals are placed into paddocks at purchase. This ensures the building up the breeder/sire herd through purchases will not take place while pasture levels are low. This is determine based on the different pastures for breeders and sires provided above.

This does not apply to young male and female separation for fattening and growth before sale as this is not the result of purchasing.

This does not relate to retaining individuals marked for sales as they are effectively already in the system.

The pasture represented by a Graze food store type is a managed paddock or field where individuals can be placed.

This entry is a drop down list of available Graze food store type resources of the Graze food store available for this simulation

An option to move to "Unspecified - general yards" is also available. This would be used to move animals back to the homestead for part of the year for lot feeding.

Requires Manage female breeders Perform female stocking

The pasture represented by a Graze food store type is a managed paddock or field where individuals can be placed.

This entry is a drop down list of available Graze food store type resources of the Graze food store available for this simulation

An option to move to "Unspecified - general yards" is also available. This would be used to move animals back to the homestead for part of the year for lot feeding.

Requires Manage male breeders Perform male stocking

The pasture represented by a Graze food store type is a managed paddock or field where individuals can be placed.

This entry is a drop down list of available Graze food store type resources of the Graze food store available for this simulation

An option to move to "Unspecified - general yards" is also available. This would be used to move animals back to the homestead for part of the year for lot feeding.

This would represent sending young steers to a paddock to fatten up before selling.

Requires Perform growing out of young males

The pasture represented by a Graze food store type is a managed paddock or field where individuals can be placed.

This entry is a drop down list of available Graze food store type resources of the Graze food store available for this simulation

An option to move to "Unspecified - general yards" is also available. This would be used to move animals back to the homestead for part of the year for lot feeding.

This would represent sending young females (e.g. Heifers) to a paddock to fatten up before selling.

Requires Perform growing out of young females

A warning will be displayed in your Descriptive Summary when these settings along with breeding style (natural mating) and castration of young males allows mating to occur in potentially unintended situations.

See also