Reproductive and Maternal Behavior of Livestock - Genetics and the Behavior of Domestic Animals - page 157

Chapter 5
Reproductive and Maternal
Behavior of Livestock
Peter J. Chenoweth * , Antonio J. Landaeta-Hern´ ndez † , and
Cornelia Fl¨ ercke ‡
*Charles Sturt University, Wagga Wagga, Australia; † Universidad del Zulia, Facultad de
Ciencias Veterinarias, Unidad de Investigaciones Zoote´cnicas, Maracaibo, Venezuela;
‡ Department of Animal Sciences, Colorado State University, Fort Collins, Colorado, USA
GENERAL INTRODUCTION
Species survival is ensured by the regular production of viable offspring. This
in turn depends upon the successful execution of a number of processes which
are behavior driven. These processes include copulation and fertilization,
pregnancy maintenance, and the subsequent successful delivery and raising of
the young. In pursuit of these outcomes, mammals have evolved widely differ-
ing mating and birthing strategies in response to a number of influences which
include susceptibility to predation, geographical dispersion and social con-
texts. Additional demands on sexual and reproductive behavior, social toler-
ance and adaptive ability have been imposed by domestication (Jensen and
Andersson, 2005; McPherson and Chenoweth, 2012 ). The fact that only 6% of
current species of ungulates and elephants are domesticated ( Tennessen and
Hudson, 1981 ) indicates that those species which did become domesticated
had predisposing behaviors and traits, many of which are reproductive or
maternal ( Chenoweth and Landaeta-Hern´ndez, 1998 ). In the process of
domestication, natural selection, which occurs during the natural breeding pro-
cess, is replaced by artificial selection, which occurs prior to breeding ( Katz,
2008 ). Artificial selection accentuates certain traits while relaxing selection
pressure on others, with the latter causing increased genetic variation. In addi-
tion, some behaviors which are important for reproduction and/or survival
lose adaptive significance ( Price, 1984 ), although this can also occur in the
absence of domestication ( Gorelick and Heng, 2011 ).
The seasonal nature of the breeding cycle in many species has evolved to
ensure that offspring are born at the most opportune time of the year for sur-
vival and growth as well as for re-mating of the dam, with this usually being
in spring. However, even in those species which have strongly seasonal