Ruminant initial cohort

CLEM.Resources.RuminantInitialCohort

The definition of a cohortClosed A group of individuals of the same breed, gender and age (or born at the same time) of individuals.

This represents a group of individuals of the same breed, gender and age. It includes the number of individuals in the cohort and the weight of individuals. A number of these components are used to define the initial herd and type of trade animals purchased.

The following parameters are associated with this component

The gender of individuals

The age of individuals in months

The number of individuals

This property is not needed and therefore not displayed when the Ruminant initial cohort is used as the child of a Specify ruminant

The weight of each individual in kg

If this value is set to 0, this cohort will be initialised using the calculated normalised weight for the age specified. See for Details/Standard Reference Weight and Normal weight section of Grow ruminants for calculations.

The individual-based ruminant modelling approach used by CLEM allows each individual to have its own weight and thus influences intake, pregnancy success, milk production and time of selling. In order to add a normally distributed spread of weights at the start of the simulation you can provide a standard deviation (S.D., provided in kg) around the weight provided which is considered the mean. As each individual in the cohort is created by the model it's weight will be randomly assigned form the distribution with most weights close to the mean and only 1 percent more than 3 standard deviaitons above or below the mean.

If you do not want any random distribution of assigned weights provide a standard deviation of 0 and all individuals will be set with the weight supplied above.

How can I calculate the standard deviation to use?

The distribution of all values around the mean will be distributed such that 68% of individuals will have a weight ±1 S.D. away from the mean, 95% ±2 S.D., and 99 % ±3 S.D. above and below. If you consider the maximum range above and below the mean that you want your weights to be allocated across and divide this vales (kg above mean to maximum weight), and divide this by three you will have the value to supply here.

Remember, there are other processes that consider the animals weight as a proportion of normalised weight for age. These weights do not represent the health (body condition) of the individual which is related to the current weight as a proportion of the maximum weight the individual has achieved, which at initialisation is the same as the weight assigned.

Note: you will need to determine this value for each cohort as each cohort will have a different weight and therefore possible range of values to supply.

A switch to indicate whether these individuals are still suckling (Checked) or have been weaned (Unchecked)

A switch to specify these individuals are breeding males (Checked) and can be treated differently.

The following components will add additional functionality to this component

A Set attribute with value component below this cohort will ensure the attribute and associated value will be applied to all individuals created from this cohort. The value supplied by this set attribute by value component will override any values set for the same named attribute from the Ruminant initial cohorts level.

A Set previous conception component below this cohort will define the conception age and therefore months pregnant of the individuals specified. The individuals must be female and of breeding age at the time of conception (see ruminant breed parameters).

See also