Genetic correlations and heritabilities for milk yield and lactation length of dairy sheep

El-Saied, U.M.; Carriedo, J.A.; Baró, J.A.; Fuente, L. F.; Primitivo, F. San

doi:10.1016/s0921-4488(97)00060-6

Cited by 19 publications

(6 citation statements)

References 13 publications

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“…The estimates of c 2 for MY 180 are always higher than those from 0.14 to 0.15 reported for milk yield standardised to different lactation lengths in the B. siciliana sheep (Portolano et al, 2001). The estimate of c 2 for LL obtained using Model 1 is basically 0 whilst for that obtained using Model 2 is nearer to that of 0.03 reported by El-Saied et al (1998b) in the Churra breed and quite far from that of 0.141 reported by Pollot and Gootwine (2001) in improved Awassi sheep.…”

Section: Resultsmentioning

confidence: 50%

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Genetic parameters affecting 180-days standardised milk yield, test-day milk yield and lactation length in Spanish Assaf (Assaf.E) dairy sheep

Gutiérrez

Legaz²,

Goyache

2007

Small Ruminant Research

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A total of 42,197 records of test-day milk yield (TDY) and 7654 lactations from 3854 individuals belonging to the Spanish Assaf (Assaf.E) breed were analysed using univariate and multivariate models to estimate genetic parameters affecting TDY, total milk yield standardised to 180 days (MY 180 ) and lactation length (LL) in order to asses their possibilities of use in the selection scheme of the Assaf.E population. Estimates of h 2 were, in general, on the lower limit of those usually reported for the three analysed traits. Estimates of heritability for MY 180 varied from 0.131 to 0.177. Estimates of h 2 for LL and TDY were consistent regardless the estimation model being of, roughly, 5% and 10%, respectively. The estimates for the permanent environmental effect (c 2 ) of TDY were consistently the same (0.27-0.28) regardless the fitted model whilst they showed large differences for LL and MY 180 . Genetic correlations were always positive and high ranging from 0.792 for the pair LL-TDY to 0.999 for the pair MY 180 -TDY. Correlations between permanent environmental effects were even higher ranging from 0.932 for the pair LL-MY 180 and 0.999 for the pair MY 180 -TDY. The advantages of using TDY as selection criterion in the Assaf.E improvement scheme are discussed.

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Section: Resultsmentioning

confidence: 50%

“…The heritability reported by El-Saied et al (1998b) for LL was estimated on data from a single flock; the authors concluded that most factors affecting LL are of non-genetic origin. However, the estimate by Portolano et al (2001) was obtained on data from 44 flocks showing large phenotypic variation for LL.…”

Section: Resultsmentioning

confidence: 99%

Genetic parameters affecting 180-days standardised milk yield, test-day milk yield and lactation length in Spanish Assaf (Assaf.E) dairy sheep

Gutiérrez

Legaz²,

Goyache

2007

Small Ruminant Research

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“…Average milk production could be considered low or medium, with yields varying from 70 to 150 kg of milk/lactation (Padeanu 2001). Although, some strains, due to selection and proper nutrition, may be able to produce yields higher than 200 kg of milk/lactation, taking into account the heritability for milk yield that ranges between 0.20 and 0.29 (El-Saied et al 1998;Legarra & Ugarte 2001). The most prominent breeds of this group are Comisana, Karagouniko, Lesvos, Podhale Zackel, Pramenka, Sarda, Sfakion, Turcana, Valachian and Vlahico.…”

Section: Introductionmentioning

confidence: 99%

Improving performance of Zackel sheep through cross-breeding with prolific Bluefaced Leicester under semi-intensive and extensive production systems

Gavojdian

Cziszter

Sossidou

et al. 2013

Journal of Applied Animal Research

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The aim of the current research was to evaluate the effects of cross-breeding Romanian indigenous Turcana (TA) ewes belonging to the Zackel breed group with prolific Bluefaced Leicester (BL) rams on the performance and reproduction rates of F 1 cross-bred descendants under semi-intensive and extensive production systems. The UK stratified sheep production system was applied for the development of the cross-breeding scheme. F 1 Bluefaced Leicester )Turcana (F 1 BL )TA) cross-bred ewes proved to be highly precocious and registered an average fertility rate of 94.7% when mated as ewe lambs, compared with 9.52% (p 50.001) of the pure-bred TA. F 1 BL) TA cross females registered an average prolificacy of 159 and 202% when mated at the ages of 8 and 18 months, respectively, while the TA ewes produced on average 112 and 127% (p 5 0.01 and p 5 0.001, respectively). 3 W: Dorper )(F 1 BL )TA) cross-breds had different (p 5 0.001) weaning weights at the age of 90 days when reared semi-intensively (31.0 kg) and extensively (27.6 kg). Introducing the stratified sheep production system into Central, Eastern and Southern Europe could prove valuable for improving meat performance on farms that keep Zackel sheep under semi-intensive and extensive production systems.

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“…Other models reported in the literature (e.g. El-Saied et al, 1998b;Hamann et al, 2004;Oravcová et al, 2006) and applied to our data are presented in Table 4 and are labelled according to the first author and year of publishing of the individual study.…”

Section: Methodsmentioning

confidence: 99%

“…Milk production is usually expressed as test-day milk yield, the total milk yield or the transformed total milk yield to standard length of the lactation period (El Saied et al, 1998a;Oravcová et al, 2006), considering that the genetic correlation between the total and standardized lactation is quite high (0.99) (El Saied et al, 1998b).…”

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confidence: 99%

Estimation of genetic parameters and evaluation of test-day milk production in sheep

Bauer¹,

Milerski²,

Přibyl³

et al. 2012

CZECH J ANIM SCI

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Genetic parameters and breeding values were estimated based on 11 708 daily milk yields from 2255 lactations (1351 sheep, 19 different flocks) between the years 2004 and 2010. The pedigree covered 2334 individuals, including both the recorded animals and their known ancestors. The fixed effects were estimated by the least-squares method, while the genetic parameters were estimated by the REML method. The data were tested by 49 models, but on the basis of the coefficient-of-determination value and the significance of the effects, only 10 models were used for REML analysis. The most suitable model was chosen on the basis of the breeding values distribution and the heritability of daily milk production, which was estimated at 0.28. The fixed effects of the flock parity number, the flock test day, and the linear and quadratic coefficients of flock's days-in-milk in the chosen model were all highly significant (P < 0.0001) for the test-day milk yield. The breeding values had a normal distribution and a standard deviation of 0.46 kg.

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Genetic correlations and heritabilities for milk yield and lactation length of dairy sheep

Cited by 19 publications

References 13 publications

Genetic parameters affecting 180-days standardised milk yield, test-day milk yield and lactation length in Spanish Assaf (Assaf.E) dairy sheep

Genetic parameters affecting 180-days standardised milk yield, test-day milk yield and lactation length in Spanish Assaf (Assaf.E) dairy sheep

Improving performance of Zackel sheep through cross-breeding with prolific Bluefaced Leicester under semi-intensive and extensive production systems

Estimation of genetic parameters and evaluation of test-day milk production in sheep

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