PRY

What is PRY

PRY is a bio-economic livestock herd/population model developed by Dr. habil. Richard Baptist (formerly of the University of Nairobi and the University of Hohenheim) in 1988. PRY is a species independent, livestock-driven, herd model, which combines deterministic and stochastic procedures and allows for assessing herd/population productivity, simulating herd/population development, comparing productivity between livestock systems and management strategies within livestock systems.

PRY derives a productivity index (PI) "total output value/dry matter intake (TOV/DMI)" as a measure of overall productivity of an animal production system. Dry matter intake is chosen as denominator in this index because feed is considered the most limiting production asset as it generally accounts for the major part of production costs and is the main input factor in extensive animal husbandry systems.

PRY in its original DOS based version consists of six single components or modules (DIC, PIC, SAM, FOC, BOI, APE). Demographic input parameters are entered and stored in DIC. Produce-related input parameters are entered and stored in PIC. Deterministic modelling components SAM, FOC, and BOI derive population structure, numeric offtake, life expectancies and potential rate of increase of population for an infinitely large, closed equilibrium population (a population at steady state) from the DIC parameters. Total offtake value per dry matter intake for different disposal strategies is derived adding information from the PIC parameters, thus the model permits to find an optimal culling strategy (FOC). With a specific culling regime specified, a detailed breakdowns of offtake and intake (BOI) can be derived. The stochastic animal population emulator APE permits the simulation of herd/population development over time.

PRY was further developed by Dr. Richard Baptist into an MS Excel add-in named HerdLife. HerdLife combined the different modules above and eased handling of the model, particularly parameter input as well as display and storage routines.

In a current effort encouraged by the model author, PRY / HerdLife will be linked to external data sources – i.e. spreadsheet or database applications often used in research projects as well as livestock management programmes such as CowSense (TM by Midwest Microsystems). Thus, input parameters can be directly read/retrieved from data either routinely collected in commercial livestock operations or data generated by research projects. The initiative is carried forth by a consortium between Science Data Services (Dr. Simon Riedel), the German Institute for Tropical and Subtropical Agriculture [www.ditsl.org DITSL] (Dr. Christian Hülsebusch and Prof. Dr. Brigitte Kaufmann) and the University of Kassel (Dr. Uwe Richter, Prof. Dr. Eva Schlecht). The consortium appreciates the generous permission of the author, Dr. habil. Richard Baptist, to further develop his valuable tool with the aim to provide a flexible decision support tool for the management of livestock systems.

In a first step, the model was transcribed into a standalone application running under Windows XP/7 named PRY 3.0 beta – which can be downloaded here for test purposes

In a next step, a MySQL database will be coupled to PRY 3.0 beta that permits translation of CowSense (TM by Midwest Microsystems) export data into demographic input parameters for PRY.

The Software

Download

Unless you are a developer or require Modules from the original DOS Software, you most proably want to use the 3.x Version of the Software, provided as an installable Windows App. Download of other Versions below

PRY 3.x

Latest Version

Version	File	ReleaseNotes
1.0.13	PRY 3.0.12 Windows Installer	abcdef.txt

Access previous Versions of PRY (As Excel File / DOS Console Programm)

• Download PRY 2.x
• Download PRY 1.x

Software User Guide

Version 3.x

Windows App the most recent Version, you most proably have this Version installed

Version 2.x

PRY realized as Modules in an Excel sheet

Version 1.x

The original PRY, a DOS console Program

Version 3.x

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Age at first Parturition

When a class mean in the first class of age at first parturition is entered which is below the average inter-litter interval, a warning shows up to recheck your values. You have three options:

• Proceed and leave your input as it is
• Correct your value
• Click the Help Button to learn why this value might be critical for your model

Literature

Many studies have been conducted by using the PRY Software. We are trying to collect all, so if you know of any further study, let us know, we will list them here. If you have any questions about those publications, you may contact DITSL .

Herd Analysis with PRY

Author	Year	Journal	Title	Link/File	Species
Baptist,R. Sommerlatte	1992	Small Ruminant Research	Evaluation of cropping strategies in game ranching using a livestock productivity model	http://dx.doi.org/10.1016/0921-4488(91)90124-9
Anonymous	1995	Wildlife and Nature	Herd Dynamics modelling applied to a Venison ranch in Kenya	PDF	Game
Fink	1990	unpublished (Diploma Thesis)	Schätzung demographischer Parameter in der wildnutzung aus ermitteltem Propulationswachstum und -struktur, Entnahmerate und Zusammensetzung der Entnahme auf einer kenyanischen Wildranch	DOI	Game
Kaufmann, B.	199x	??	??	??	Cattle/Camel
Huelsebusch, C.	199x	??	??	??	Cattle/Camel
Dos Santos / Neuzling, A.	200x	??	??	??	Cattle
Dickhöfer, U.	200x	??	??	??	Small Ruminant
Riedel, S.	200x	??	??	??	Pigs
Hofsommer	200x	??	??	??	Cattle
Aufderheide, M.	200x	??	??	??	Cattle

Methodology

Author	Year	Journal	Title	Link/File
Baptist, R.	1987	Agricultural Systems	Computer Simulation of Monitoring Herd Productivity under extensive Conditions: Sampling Error of Herd Size and Offtake Rate	http://dx.doi.org/10.1016/0308-521X(87)90003-5
Baptist, R.	1988	Agricultural Systems	Herd Flock Productivity Assessment using the Standard Offtake and the Demogram	http://dx.doi.org/10.1016/0308-521X(88)90022-4
Baptist, R.	1991	unpublished	PRY Manual	PDF
Baptist, R.	1992	Habilitation	Population Dynamics and Productivity at the stationary State of Culling Regimes in Livestock Herds and Flocks	PDF