Effects of nutrition level during lactation and rearing periods on growth patterns, puberty onset and fertility rate in beef heifers
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Date
2014
Authors
Rodríguez Sánchez, José AntonioSanz Pascua, Albina
Casasús Pueyo, Isabel
Journal Title
Journal ISSN
Volume Title
Publisher
American Society of Animal Science
Typology
Proceedings Paper , articleArticle
Abstract
This study analysed the effects of different
nutrition levels from heifer birth to first Timed Artificial
Insemination (TAI) at 15 months, on their growth patterns,
puberty onset and fertility rate. Twenty-nine Parda de Montaña
heifers, born in autumn, were assigned to two growth rates in
the lactation period (0-6 months: 700 vs. 1000 g/d, to Low
(L) and High (H), respectively) and in the rearing period
(6-15 months: 700 vs. 1000 g/d, to Low (L) and High (H),
respectively), resulting in 4 treatments: LL, LH, HL, HH. At
15 months of age an Ovsynch protocol with an intravaginal
progesterone device was used to synchronize and breed the
heifers. Weight was taken weekly from birth until breeding
season was finished to study the evolution of weight and
average daily gain (ADG) along the experiment. Heifers were
bled weekly throughout the rearing period to determinate the
onset at puberty through plasma progesterone concentration.
Heifers’ average daily gains were influenced by the lactation
and the rearing nutrition levels, animals compensating the
growth rates in the different phases. The age at onset of
puberty was higher in the animals receiving the Lactation low
nutrition level (P<0.01) and the Rearing low nutrition level
(P<0.001). Heifers of all lots showed similar weights at onset
of puberty (55% adult weight), conception age (16.4 months)
and fertility rate (89%). It can be concluded that the advance
of the first service from 21 to 15 months of age is possible
in extensive systems of beef cattle, if growth rates of 1 kg/d
during lactation or/and rearing are guaranteed. Additional
research is needed to determinate the impacts on adult size
and frequency of dystocia at first and subsequent calvings of
early-bred heifers
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Bibliographic citation
Proceedings Volume 65. Western Section American Society of Animal Science: San Angelo, Texas, 25 - 27 June 2014, p. 191-195
AGROVOC subjects
ProductividadGanado bovino
Etapas del desarrollo animal