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Titolo:
The potential for identifying heritable endocrine parameters associated with fertility in post-partum dairy cows
Autore:
Darwash, AO; Lamming, GE; Woolliams, JA;
Indirizzi:
Univndottingham, Cattle Fertil Res Grp, Loughborough LE12 5RD, Leics, Engla Univ Nottingham Loughborough Leics England LE12 5RD E12 5RD, Leics, Engla Roslin Inst, Roslin EH25 9PS, Midlothian, Scotland Roslin Inst Roslin Midlothian Scotland EH25 9PS 9PS, Midlothian, Scotland
Titolo Testata:
ANIMAL SCIENCE
, volume: 68, anno: 1999,
parte:, 2
pagine: 333 - 347
SICI:
1357-7298(199903)68:<333:TPFIHE>2.0.ZU;2-X
Fonte:
ISI
Lingua:
ENG
Soggetto:
OVARIAN FOLLICULAR DYNAMICS; QUANTITATIVE TRAIT LOCI; ESTROUS-CYCLE; GENETIC-PARAMETERS; HOLSTEIN COWS; MILK-YIELD; REPRODUCTIVE-PERFORMANCE; PRIMIPAROUS HOLSTEINS; POSTPARTUM OVULATION; CATTLE;
Keywords:
dairy cows; fertility; heritability; hormone secretion; marker-assisted selection; quantitative trait loci;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
90
Recensione:
Indirizzi per estratti:
Indirizzo: Darwash, AO Univ Nottingham, Cattle Fertil Res Grp, Sutton Bonington, Loughborough LE12 Univ Nottingham Sutton Bonington Loughborough Leics England LE12 5RD
Citazione:
A.O. Darwash et al., "The potential for identifying heritable endocrine parameters associated with fertility in post-partum dairy cows", ANIM SCI, 68, 1999, pp. 333-347

Abstract

Fertility is an important component of herd production efficiency, as eachadditional oestrous cycle that does not result in a planned pregnancy addsto the cost of dairy farming. In addition to the negative impact on milk production, the high costs of veterinary intervention, ve-insemination and herd replacement, subfertility can affect the rate of genetic gain in traitsof economic merit. In contrast with the steady increase in average milk yield per cow during the last 30 years, there has been a decline in conception rate to artificial insemination in both the USA and in the UK. The genetic correlation between yield and fertility has been equivocal. Attempts to improve the reproductive efficiency in dairy cattle through breeding and selection have been frustrated to date by the lack of heritable reproductive parameters conducive to high fertility. However, the traditional fertility parameters of interval to first service, services per conception,days open and calving intervals are highly influenced by managerial decisions and have, as expected, heritabilities too low to permit a meaningful genetic gain through selection. An alternative approach is to use the growingbody of evidence that the majority of endocrine factors affecting reproduction are a result of gene expression at the hypothalamic, pituitary, ovarian or uterine level. Mechanisms such as commencement of post-partum cyclicity, follicle wave patterns, manifestation of oestrus, luteal competence and level of embryo mortality ave appropriate for study. Research is required to investigate the genetic component of the variation between animals in these parameters, their phenotypic and genetic correlations with fertility andtheir association with other production traits. In summary: (a) subfertility is a syndrome with multiple causes and only the symptom in common; (b) improvement in fertility will continue to be frustrated until recorded traits provide move accurate estimates of breeding values; (c) techniques are now available to estimate the genetic variation inphysiological components conducive to improved reproductive efficiency; (d) once the heritable components of fertility are identified, these tools could be introduced into progeny testing and breeding nuclei, from which the genetic improvement can be widely disseminated. Selection for those components with sufficient genetic variation will result in the improvement of theintegral endocrine and other physiological mechanisms favourably correlated with high fertility (e) these tools may also assist in detecting quantitative trait loci for faster genetic gain through markers-assisted selection.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 10/07/20 alle ore 18:50:07