Ruminant type

CLEM.Resources.RuminantType

This resource represents an individual ruminant species or breed.

The ruminant growth model used by CLEM is based on that developed for the IAT and NABSA models using the Nutrient requirements of domesticated ruminants (NRDR, 2007) and allows for the simulation of a wide range of ruminants using the one component. This resource represents an individual ruminant species (e.g. cattle, goats, sheep or buffalo) or a breed (e.g. BALI SPA or Bos indicus). This component holds all the ruminant coefficients that describe the growth and breeding of the individuals and controls the initialisation of the herd and tracking of current prices.

The Ruminant Type contains a larger number of parameters in order to specify the animals growth and breeding. This component benefits from a tree based grouping of parameters to help you easily locate the parameters of interest. The parameters are further grouped by those you will likely need to change (Basic) and those that should only be modified by Advanced users. All the currently parameterised ruminant types can be obtained from the CLEM toolbox which provides an easy means of finding the most similar ruminant and modifying the parameters provided. (See Managing model components to get these into your simulation tree).

The following ruminant parameters are those that most frequently need to be adjusted by the user to modify a ruminant type provided for a farm set up.

These relate to the ruminant type in general.

This is the name of the breed or type of ruminant for which the following parameters are defined. This is different to the name provided in the user interface tree for this Ruminant type component. It is the name of the component in the tree that will be provided in drop down lists for managing ruminants in your simulation. For example, there may be a breeding herd and trade herd used in the simulation. These could be named "Breeding" and "Trade" in the tree, but both use the parameters for Bos indicus and would use copies of the same component (from a toolbox or another simulation) and these would have this breed property set to "Bos indicus"

This is the weight (in kg) of a reference adult female. See Grow ruminants for details on the use of Standard Reference Weight

This is the weight (in kg) of one animal equivalent. For example, for cattle this would be a standard steer weight. This value is used to calculate the number of animal equivalents in the herd.

An array of three values (entered separated by commas) defining the minimum, normal (middle) and maximum values to use for the Body Condition Score where the mid score represents an animal with the average expected normal weight for age. For sheep and cattle this is usually on a scale from 0 to 5 with a value of 3 representing the normal weight for age. Values less than 3 represent underweight with a greater chance of mortality though being underweight at the lowest scores. Scores greater than 3 represent an animal in better than average condition. The score is limited to the minimum and maximum values. See Individual ruminant for details of the calculation of Body Condition Score property.

The rate at which the ratio of animal live weight to normalised weight equates to each unit change in the body condition score away from the normal score when the animal weight equals the normalised weight for age (i.e. a ratio of 1). See Individual ruminant for details of the calculation of Body Condition Score property.

These parameters relate to the growth of the ruminant type.

The breed factor (Kme) used in the calculation of maintenance energy. For full details see Energy requirements for Weight gain and milk production in Ruminant Activity Grow.

These parameters relate to the diet intake of the ruminant type.

When enabled this switch will ensure that the green limits set for the diet are enforced. When turned off the animals are able to have a second take of any green limiting pools if their intake was not satisfied. This will mean that a larger proportion of green pasture will be consumed if this switch is turned off.

These parameters relate to the survival of the ruminant type.

Even if animals are well fed and proper animal husbandry practices are followed some individuals will die. This property provides the annual proportion of individuals in the population that die (i.e. 0.03 represents 3% mortality). This is applied across all individuals regardless of age once weaned. There are additional mortality rates for the fetus and new born individuals. Additional mortality will also apply based on an individuals weight in relation to the maximum weight achieved to account for underweight individuals.

Rate between 0 and 1

See Grow ruminants for details of mortality/survival calculations.

These parameters relate to calculating milk production of the ruminant type.

This represents the period of time (in days) after birth a female will lactate for and produce milk.

This is the maximum milk yield (kg/day) during lactation. This will be used to define the milk production curve for the ruminant type.

These parameters relate to breeding for this ruminant type

This is the minimum age (months) before mating is possible.

This is the minimum size (proportion of SRW) before mating is possible.

Proportion between 0 and 1

This sets a maximum age below which mating is possible in breeders. This allows you to ensure that mating will stop before old females are sold off. A value greater than or equal to the maximum breeder age will ensure breeding has ceased when old females are sold and avoid selling old breeders while pregnant.

This parameter will only be used in Controlled mating when selecting females for breeding. No maximum age for mating is used in uncontrolled mating.

This represents the minimum period of time (in days) after birth before conception is again possible.

The rate (proportion of pregnancies) at which multiple births are conceived. You can add as many values as needed to this parameter as a comma separated list. These values will represent rate of twins, triplets, quadruplets, ... etc. For example if 20% of pregnancies carried twins and 4% carried triplets, you would supply "0.2,0.04" to this parameter.

This parameter should be left blank if no multiple births occur for the breed.

These proportions represent the rates at pregnancy and not birth as the prenatal mortality rate will apply to all individuals prior to birth resulting in a drop in individuals reaching term.

The following ruminant parameters should only be modified by advanced users. Altering these values will require expert understanding and so are unlikely to change once defined for a particular ruminant type.

These relate to the ruminant type in general. See Grow ruminants for details on the use of Standard Reference Weight.

This multiplier determines the Standard Reference Weight (SRW) of a male in relation to the female SRW. For example a value of 1.2 would mean the standard adult male would be 1.2 times larger than the standard female (parameter set in Basic-Growth parameters).

This multiplier determines the maximum size possible for an individual in relation to its Standard Reference Weight (SRW). As SRW differs between males and females based on previous parameters, the maximum size of males and females will also differ.

These parameters relate to the growth of the ruminant type. See Grow ruminants for details on the use of Standard Reference Weight and growth, energy and intake descriptions.

Two parameters (the coefficient and intercept) are provided to determine the efficiency of use of energy for maintenance.

km = coefficient * EM/EG + intercept

where EM is the proportion of digestible energy that is metabolisable (assumed 0.81) and EG is the Gross energy content of feed (MJ/kg DM, set in Grow ruminants)

Two parameters (the coefficient and intercept) are provided to determine the efficiency of use of energy for growth.

kg = coefficient * EM/EG + intercept

where EM is the proportion of digestible energy that is metabolisable (assumed 0.81) and EG is the Gross energy content of feed (MJ/kg DM, set in Grow ruminants)

Two parameters (the coefficient and intercept) are provided to determine the efficiency of use of energy for lactation.

kl = coefficient * EM/EG + intercept

where EM is the proportion of digestible energy that is metabolisable (assumed 0.81) and EG is the Gross energy content of feed (MJ/kg DM, set in Grow ruminants)

Three parameters (the exponent, coefficient and intercept) are provided to determine the maintenance energy required for an individual based on its weight and age (ref SCA p.24).

See Grow ruminants for details of energy calculations.

This defines the maximum age (in years) for the energy for maintenance calculation.

See Grow ruminants for details of energy calculations.

Two parameters (intercept #1 and intercept #2) are used to calculate the empty body gain.

See Grow ruminants for details of energy calculations.

The growth efficiency is used to calculate the energy available for body mass change.

See Grow ruminants for details of energy calculations.

This parameter is used to calculate normalised body weight of individuals.

See Grow ruminants for details of Normalised Weight calculations.

This parameter is used to calculate normalised body weight of individuals.

See Grow ruminants for details of Normalised Weight calculations.

This is the age (in months) where natural weaning will take place if not weaned by management (see Wean ruminants).

The gestation length will be used for this value if 0 is supplied as this parameter.

These parameters relate to breeding for this ruminant type. See Breed ruminants for details of calculations.

The mass at birth provided as a proportion of Standard Reference Weight.

This allows for a set ratio of male to female offspring. The default is 0.5 with equal probability of giving birth to a male or female.

Two parameters (intercept and coefficient) are to calculate the inter parturition interval (months).

NOTE: These parameters are no longer used in CLEM as the individual based ruminant model with breeding timers and the minimum number of days between last birth and conception will determine the interval along with the success of conception and pregnancies based on breeding female's body condition.

This period (in months) is the gestation length.

This proportion of SRW determines the size below which there is no successful pregnancy.

This determines the maximum number of matings per day per breeding male when uncontrolled breeding is used. This ensure that large breeder herds cannot be serviced unrealistically by a low number of males.

This parameter defines the mortality rate between conception and birth.

These parameters are associated with determining intake and feed quality. See Graze ruminants and Grow ruminants for details of calculations.

The coefficient and intercept used to calculate potential intake in relation to the live weight of the individual.

Coefficient to calculate crude protein required from diet dry matter digestibility.

Coefficient to calculate crude protein supply from percent Nitrogen in diet (x 62.5) to give protein.

Maximum proportion of green pasture permitted in diet to calculate green pool limits.

Coefficient to calculate green pool limits

Value used in equation to calculate green pool limits

The IntakeCoefficientBiomass parameter is used to reduce intake from grazing as a function of pasture biomass and therefore the ability to find and consume pasture in the allowed grazing time. For details see Potential intake pasture Biomass limiter.

This property allows you to set a maximum intake permitted as a multiplier of Potential Intake. This value only applies to manual feeding styles (i.e. Specified daily amount, Specified daily amount per individual, Proportion of weight and Proportion of feed available) that allow excess feed to be provided . This multiplier does not influence grazing intake calculations and will not consider any previous overfeeding when grazing is performed after manual feeding.

>= 1

The following five parameters are used to determine the potential and actual milk intake from sucklings and define a potential intake (ensures individual is able to be fed or graze pasture) as a size when milk intake drops below critical levels. These parameters are designed to allow a slow progression from suckling to fodder consumption for juveniles as the mothers' milk production drops with time since birth (or the individual is orphaned). For full details see Potential intake in Ruminant Activity Grow.

The coefficient and intercept of the linear equation based on live weight (kg) to calculate potential milk intake. See Potential intake.

Maximum daily milk intake (L/day). This limits the energy available from milk intake as the minimum of energy from milk consumed, or from maximum milk intake will be provided.

The maximum milk intake as a proportion of live weight before calculating a potential intake and allowing fodder substitution. See Potential intake.

Max juvenile (suckling) fodder and feed intake as proportion of live weight (kg).

The proportion of milk intake to be deducted maximum non-milk intake calculated from live-weight to determine potential intake. 1 - all milk is included in potential intake, 0 - no milk considered in potential intake.

These parameters are used to calculate the age adjusted mortality rate.

The Body Condition Score below which the additional poor condition mortality is applied to the individual. See the Basic/General section above for the parameters required and Individual ruminant for details of the calculation of Body Condition Score.

This approach is used when the previous Proportion of body weight needed for survival parameter is set to a value less than 0 (off).

The additional mortality rate for individuals at the lowest Body Condition Score. Individuals at the lowest score will have this additional chance of dying applied each timestep based on their poor body condition as a result of under nutrition. See the Basic/General section above for the parameters required and Individual ruminant for details of the calculation of Body Condition Score.

This approach is used when the previous Proportion of body weight needed for survival parameter is set to a value less than 0 (off).

This parameter defines the body weight as a proportion of Standard Reference Weight below which the individual will die.

A value less than 0 will switch this approach off and use the Mortality rate for low Body Condition Score parameter which is now the preferred approach.

Three parameters (the exponent, coefficient and intercept) are provided to determine the age adjusted mortality rate.

See Grow ruminants for details of mortality/survival calculations.

Two parameters (the exponent and coefficient) are provided to determine the adjusted mortality rate based on the mothers weight.

A third parameter (maximum) is used to define the maximum juvenile mortality possible.

See Grow ruminants for details of mortality/survival calculations.

These parameters relate to calculating milk production of the ruminant type. See Milk production for details of lactation calculations.

Three constants (A, B and C) are required to determine the additional intake consumed to account for lactation demands.

Two parameters are provided to determine the shape of the milk production curve based on whether the female has a suckling offspring or not.

This is a milk production offset value (usually 4)

The number of days before peak milk production.

These parameters are used to determine the amount of other products created by the herd

The rate at which wool is produced as a proportion of intake.

The rate at which cashmere is produced as a proportion of intake.

This parameters determines the creation of methane as a proportion of intake (Charmley, XXXX)

The following components are required to set up this resource

The Initial cohorts component is used to define the number of individuals in the herd at the start of the simulation.

Each Ruminant type component requires conception details to be supplied. There are currently three different means of calculating conception rates based on the previous IAT and NABSA models and a new method taking advantage of the individual-based herd model (see Ruminant conception for details).

The following components will add additional functionality to this resource

The Animal pricing component is required if you are undertaking any activities relating to buying or selling stock and have Finances included in your simulation resources.

See also