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Titolo:
Genetic and economic relationships between somatic cell count and clinicalmastitis and their use in selection for mastitis resistance in dairy cattle
Autore:
Kadarmideen, HN; Pryce, JE;
Indirizzi:
Scottish Agr Coll, Dept Anim Breeding & Genet, Anim Biol Div, Edinburgh EH9 3JG, Midlothian, Scotland Scottish Agr Coll Edinburgh Midlothian Scotland EH9 3JG lothian, Scotland
Titolo Testata:
ANIMAL SCIENCE
, volume: 73, anno: 2001,
parte:, 1
pagine: 19 - 28
SICI:
1357-7298(200108)73:<19:GAERBS>2.0.ZU;2-1
Fonte:
ISI
Lingua:
ENG
Soggetto:
COMMON HEALTH DISORDERS; PROTEIN YIELD; SCORE; PARAMETERS; TRAITS; FERTILITY; HOLSTEINS; INDEX;
Keywords:
dairy cattle; economic values; genetic parameters; mastitis; somatic cell count;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
36
Recensione:
Indirizzi per estratti:
Indirizzo: Kadarmideen, HN Scottish Agr Coll, Dept Anim Breeding & Genet, Anim Biol Div, W Mains Rd, Edinburgh EH9 3JG, Midlothian, Scotland Scottish Agr Coll WMains Rd Edinburgh Midlothian Scotland EH9 3JG
Citazione:
H.N. Kadarmideen e J.E. Pryce, "Genetic and economic relationships between somatic cell count and clinicalmastitis and their use in selection for mastitis resistance in dairy cattle", ANIM SCI, 73, 2001, pp. 19-28

Abstract

Clinical mastitis (CM) and monthly test-day somatic cell count (SCC) records on Holstein cows were used to investigate the genetic and economic relationship of lactation average (of natural logarithms of) monthly test-day SCC (LSCC) with CM. After editing, there were 23663 lactation records on 17937 cows from 257 herds. Three groups of herds were first identified as having low (L), medium (M) and high (H) incidences of CM from the original or pooled (P) data set. Genetic parameters were estimated for the original and three data sub-sets (derived from the three herd groups). Expected genetic responses to selection against CM were calculated using genetic parameters of each data set separately, with an adapted version of the UK national index (pound PLI-profitable lifetime index). Indirect economic values of SCC (EVSCC) were calculated as the direct cost of CM per cow per lactation weighted by the genetic regression coefficient of CM lactation records on their sires' predicted transmitting ability for SCC (PTA(SCC)). All genetic regression analyses were based on linear and threshold-liability models. Heritabilities and repeatabilities, respectively, were 0.034 and 0.111 for CM and 0.120 and 0.347 for LSCC in the original data set. Genetic, permanent environmental, residual and phenotypic correlations between CM and LSCC for the original (pooled) data set were 0.70, 0.44, 0.13 and 0.20, respectively. Parameter estimates for the three herd groups differed, with magnitude of the estimates increasing with increase in incidence from L to H herd groups. The EVSCC per unit of PTA(SCC) for L, M, H and P herd groups, respectively, were pound0.04, pound0.15, pound0.33 and pound0.18 on the observed and pound0.86, pound0.96, pound1.22 and pound1.10 on the underlying-liability scales. Selection for mastitis resistance, using SCC as an indicator trait in an extended version of pound PLI, resulted in a selection response of 0.9, 2.1, 1.7 and 1.9 more cases per 100 cows after 10 years of selection in L, M, H and P herd groups, respectively. These results suggest that genetic responses to selection for CM resistance as well as the EVSCC are specific to herd incidence and hence would be appropriate for customized selection indexes. The increase in CM cases was greater when CM was excluded from the poundPLI (2.8 v. 1.9), hence it is recommended that CM should be included in the breeding goal in order to arrest further decline or to make improvement in genetic resistance to clinical mastitis.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 19/09/20 alle ore 21:20:17