Breed for milking timer

Females can be rested after lactation to allow for recovery of condition prior to the next mating. This specifies the number of time steps (months) to rest.

As milk production declines in the later stages of lactation, you may need to shorten the lactation period and get the female back in calf for the next milking opportunity. This parameter specifies how many months short of the full lactation period the breeder can be mated.

At the start if the simulation this component will get the number of months of milk production from the breed parameters of the breed associated with the parent (grandparent) Breed ruminants which may be modified by the Shorten lactation parameter. The minimum conception interval is calculated the previous value, Gestation length and Rest months. From this value we can determine the number of milkings (lactations) needed to cover the conception interval (MilkingsPerConceptionCycle). We also calculate the end of gestation cycle offset (StartBreedCycleGestationOffsett) that determines when the next breeding cycle commences from currently pregnant breeders.

This component subscribes to the CLEMDoCutAndCarry clock event each month (see Events) to perform calculations to determine if breeding is needed. While not specifically associated with this activity the timing of CLEMDoCutAndCarry ensures that all calculations are performed before the important CLEMAnimalBreeding event.

A list of all breeders in the herd is provided which is then reduced to only those less than the maximum breeding age (respected by controlled mating) and if no individuals are found the timer returns false and no controlled mating is (can be) performed. The maximum number possible for each breeding cycle (MaximumBreedersPerCycle) is then calculated from the number of breeder and MilkingsPerConceptionCycle.

Those breeders currently lactating are next found and if they exist, decisions can be made about the cycle and timing of next conception. If the StartBreedCycleGestationOffsett is positive (starts after birth), this means there is a period immediately after birth where there cannot be any individuals mated, or the next cycle will not commence at the correct time. If individuals are inside this zone, no breeding occurs.

Next, the individuals currently pregnant are found. This group gives us further insight into the state of the breeding/lactation cycle. We can estimate the number of lactation cycles expected within the breed gestation length

This value is the ration of lactation length to gestation length. A value less than 1 means there are multiple breeding windows during the gestation period to ensure continuous milk production.

Next, those pregnant within the first lactation cycle of gestation are found. It is only this pool of individuals that can be added to via breeding to influence future lactation. This group can be increased up to MaximumBreedersPerCycle. For this calculation we require an additional user defined property BreedingSpreadMonths that defines how spread out conceptions can be across this window, or how clumped the births and lactation should be. A value of one will ensure all births are in the same month, but may also limit the ability to breed the maximum number required.

These calculation allow us to determine the number needed. This number of individuals are taken from the list of those able to breed this time step and offered to the Controlled mating activity to proceed with mating.

This process is designed to handle the scope of scenarios with respect to the conception and lactation status of the herd, the number needed and the lactation cycle to either enable or disable this timer and restrict the performing of the controlled mating component.