A study on two-sex population model with varying growth rates
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Date
2008
Authors
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Journal ISSN
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Publisher
CCSHAU
Abstract
The model of Lewis and Leslie (1945, 1948) has been
extensively used for the study of population growth in various
fields. However, complex growth structures require the use of
more general models. The model of Kapur (1979) allows
harvesting in the system, is an initial step to move in this
direction. However, the need is being felt to develop more general
models considering the effect of variable growth rates along with
harvesting on the reproductive structure of living organisms.
In the present work, a two-sex age-dependent population
growth model is proposed where birth, death and harvest rates of
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males and females are the functions of three population groups
viz. pre-reproductive, more-reproductive and less-reproductive.
A population growth model has been developed with
different birth, death, harvesting and migration rates of three age
groups of males and females. The model is useful for projection of
cattle population in different age groups. Emotions for growth,
extinction and stability of the population have also been derived.
The model has been applied on the crossbred cattle population by
taking 11 years data (1995-2005) collected from Department of
Animal breeding, CCS HAU, Hisar. The projected population of
males and females in three age groups have also been found after
testing the validity of model. A uniform harvesting rate have also
been derived for stable population structure observed and
projected population structure for males and females of three age
groups with given harvesting rate as well as uniform harvesting
rate have also been shown graphically.
Description
Keywords
Harvesting, Biological development, Population dynamics, Sexual reproduction, Biological phenomena, Developmental stages, Livestock, Animal husbandry, Fruits, Animal population