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Abstract

Management, nutrition, production, and genetics are
the main reasons for the decline in fertility in the modern
dairy cow. Selection for the single trait of milk
production with little consideration for traits associated
with reproduction in the modern dairy cow has produced
an antagonistic relationship between milk yield
and reproductive performance. The outcome is a multifactorial
syndrome of subfertility during lactation; thus,
to achieve a better understanding and derive a solution
~t is necessary to integrate a range of disciplines, includmg
genetics, nutrition, immunology, molecular biology,
endocri~ology, metabolic and reproductive physiology,
and ammal welfare. The common theme underlying
the process is a link between nutritional and metabolic
inputs that support complex interactions between the
gonadotropic and somatotropic axes. Multiple hormonal
and metabolic signals from the liver, pancreas,
muscle, and adipose tissues act on brain centers regulating
feed intake, energy balance, and metabolism.
Among these signals, glucose, fatty acids, insulin-like
g;rowth factor-I, insulin, growth hormone, ghrelin, leptin,
and perhaps myostatin appear to play key roles.
Many of these factors are affected by changes in the
somatotropic axis that are a consequence of, or are
needed to support, high milk production. Ovarian tissues
also respond directly to metabolic inputs, with
consequences for folliculogenesis, steroidogenesis, and
Received December 18, 2006.
Accepted May 2,2007.
'Note: This paper was written by the participants of a workshop
organized by Lucia M. Chagas ofDexcel Ltd., New Zealand. The other
aut,hors are listed alphabetically.
-Corresponding author: lucia.chagas@dexcel.co.nz
the development ofthe oocyte and embryo. Little doubt
exists that appropriate nutritional management before
and after calving is essential for successful reproduction.
Changes in 'body composition are related to the
processes that lead to ovulation, estrus, and conception.
However, better indicators of body composition and
measures of critical metabolites are required to form
precise nutritional management guidelines to optimize
reproductive outcomes.
The eventual solution to the reduction in fertility will
be a new strategic direction for genetic selection that
includes fertility-related traits. However, this will take
time to be effective, so, in the short term, we need to gain
a greater understanding of the interactions between
nutrition and fertility to better manage the issue. A
greater understanding of the phenomenon will also provide
markers for more targeted genetic selection. This
review highlights many fruitful directions for research,
aimed at the development of strategies for nutritional
management of reproduction in the high-producing
subfertile dairy cow.

Item Type:	Article
Authors/Creators:	Chagas, LM and Rhodes, FM and Roche, JR and Thatcher, WW and Webb, RR and Bass, JJ and Blache, D and Burke, CR and Kay, JK and Lindsay, DR and Lucy, MC and Martin, GB and Meier, S
Keywords:	subfertility, high-producing dairy cow
Journal or Publication Title:	Journal of Dairy Science
Publisher:	American Dairy Science Association
ISSN:	0022-0302
DOI / ID Number:	https://doi.org/10.3168/jds.2006-852
Item Statistics:	View statistics for this item

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