Comparisons of dairy breeds in the United States

Dairy breeds have been thoroughly studied with
respect to production and type traits, and their
performance is acceptably well known. Besides, as a
result of genetic selection, production traits have
greatly increased through time. Contrastingly, scarce
or even null improvement has occurred for other
important traits, sometimes called fitness traits,
which include fertility and longevity. The dairy
industry is presently less concerned about production
and focusing more on improving, or at least,
preserving, those traits. Fertility and Longevity are
complex and low heritable and can be evaluated in
several indirect ways. The general objective of the
research was to compare the three most abundant
breeds in the United States for some
fertility-related and longevity-related traits. This
work comprises two studies. The first one aimed to
evaluate breed differences for heat-stress
resistance, and the second one designed to compare
and make inferences about survival-related traits,
assessing breed by region interactions for seven
regions of the United States using linear and
nonlinear models. This work should be of interest to
anyone related to dairy science.

Autorentext

Teresa B. Garcia-Peniche, PhD in Dairy Science: Studied at
Virginia Polytechnic Institute and State University. Animal
breeding scientist at National Institute of Agronomy, Forestry
and Animal Science (INIFAP), Research Center La Posta, in Paso
del Toro,
VER. Mexico.

Klappentext

Dairy breeds have been thoroughly studied with
respect to production and type traits, and their
performance is acceptably well known. Besides, as a
result of genetic selection, production traits have
greatly increased through time. Contrastingly, scarce
or even null improvement has occurred for other
important traits, sometimes called fitness traits,
which include fertility and longevity. The dairy
industry is presently less concerned about production
and focusing more on improving, or at least,
preserving, those traits. Fertility and Longevity are
complex and low heritable and can be evaluated in
several indirect ways. The general objective of the
research was to compare the three most abundant
breeds in the United States for some
fertility-related and longevity-related traits. This
work comprises two studies. The first one aimed to
evaluate breed differences for heat-stress
resistance, and the second one designed to compare
and make inferences about survival-related traits,
assessing breed by region interactions for seven
regions of the United States using linear and
nonlinear models. This work should be of interest to
anyone related to dairy science.