Estimativas de Parâmetros fenotípicos e ambientes das Produções de Leite no Dia do Controle e em 305 Dias de Lactação em vacas da Raça Gir

Ledic, Ivan Luz; Verneque, Rui da Silva; Martinez, M. L.

doi:10.1590/s1413-70542003000400026

Cited by 3 publications

(8 citation statements)

References 7 publications

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“…Genetic correlations between MY305 and TDMY were all positive and high (Table 4), indicating that the relationships between any of the partial yields and MY305were always favorable. These estimates are similar to those reported by Gadini et al (1997), Machado et al (1999) and Ferreira et al (2003) for the Holstein breed (0.72-1.0), and by Ledic et al (2002) and Herrera et al (2008) for the Gyr breed (0.68-1.0). Genetic correlations between LL and TDMY were also high and positive (Table 5) and tended to gradually increase across test days.…”

Section: Discussionsupporting

confidence: 92%

“…In a study involving dairy Gyr cows, Herrera et al (2008) estimated heritabilities for firstlactation TDMY ranging from 0.14 (eighth month) to 0.34 (first month). Similar results had been previously reported by Ledic et al (2002) who analyzed data from the first three lactations of Gyr cows and observed heritabilities ranging from 0.14 in the tenth month to 0.24 in the first month. Although the magnitudes of heritability in the present study were similar to those found by the last authors, the maximum heritability was observed not on the first month, but on the second, which might be explained by differences between breeds in the shapes of lactation curves, particularly during early lactation.…”

Section: Discussionsupporting

confidence: 91%

“…The heritability for MY305 was 0.24, a value similar to that found in studies with Holstein cattle (Bignardi et al, 2008;Ferreira et al, 2003;Melo et al, 2005). For the Gyr breed, Herrera et al (2008) reported a heritability of 0.29 and Ledic et al (2002) of 0.19,but with different data sets and statistical models. El Faro and Albuquerque (2003) found a heritability of 0.27 for a Caracu population.…”

Section: Discussionsupporting

confidence: 78%

“…Relative efficiencies on MY305, based on these TDMY, would be around 90%. Herrera et al (2008) and Ledic et al (2002) also found maximum relative efficiencies for test-day records on the improvement of MY305, for the period including the first and second thirds of the lactation, with the Gyr breed. The same have been observed by Ribas and Perez (1990) and Melo et al (2005), for the Holstein breed.…”

Section: Discussionmentioning

confidence: 81%

“…Referring to the Zebu breeds, some studies have been conducted referring to estimates of genetic parameters and comparisons among lactation, repeatability, or random regression models with the Gyr breed Herrera et al, 2008;Ledic et al, 2002). Freitas et al (2010) estimated genetic parameters for TDMY and persistency of lactation measurements for a Guzerat population in Brazil, using random regression models.…”

Section: Introductionmentioning

confidence: 99%

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Genetic parameters for test-day milk yield, 305-day milk yield, and lactation length in Guzerat cows

et al. 2013

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a b s t r a c tMilk production in tropical environments requires the use of crossbreeding systems including breeds well adapted to harsh conditions, but with lower productivities when compared to specialized breeds. Besides the genetic improvement for milk production, lactation lengths also need to be studied for most of these breeds. Accordingly, genetic parameters were estimated for 305-day cumulative milk yield (MY305), test-day milk yield (TDMY), and lactation length (LL) using information from the first lactations of 2816 Guzerat cows selected for milk production in 28 herds in Brazil. Contemporary groups were defined as herd, year and season of the test for TDMY, and as herd, year and season of calving for MY305 and LL. Variance components were estimated with the restricted maximum likelihood method under a multi-trait animal model. Heritabilities estimated for TDMY ranged from 0.16 to 0.24, and were 0.24 and 0.12 for MY305 and LL, respectively. Genetic correlations were high and positive, ranging from 0.51 to 0.99 among TDMY records, from 0.81 to 0.98 between each TDMY and MY305, and from 0.71 to 0.94 between each TDMY and LL. Genetic parameters obtained in this study indicated the possibility of using test-day records for the prediction of breeding values for milk yield in this population of the Guzerat breed. The use of TDMY as selection criteria would result in indirect gains in MY305 and LL. However, the highest response to selection for MY305 would be obtained by direct selection for this trait.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionsupporting

confidence: 91%

Section: Discussionsupporting

confidence: 78%

Section: Discussionmentioning

confidence: 81%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Genetic parameters for test-day milk yield, 305-day milk yield, and lactation length in Guzerat cows

et al. 2013

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Genetic parameters for milk, fat and protein yields in Murrah buffaloes (Bubalus bubalis Artiodactyla, Bovidae)

et al. 2010

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The objective of the present study was to estimate genetic parameters for test-day milk, fat and protein yields and 305-day-yields in Murrah buffaloes. 4,757 complete lactations of Murrah buffaloes were analyzed. Co-variance components were estimated by the restricted maximum likelihood method. The models included additive direct genetic and permanent environmental effects as random effects, and the fixed effects of contemporary group, milking number and age of the cow at calving as linear and quadratic covariables. Contemporary groups were defined by herd-year-month of test for test-day yields and by herd-year-season of calving for 305-day yields. The heritability estimates obtained by two-trait analysis ranged from 0.15 to 0.24 for milk, 0.16 to 0.23 for protein and 0.13 to 0.22 for fat, yields. Genetic and phenotypic correlations were all positive. The observed population additive genetic variation indicated that selection might be an effective tool in changing population means in milk, fat and protein yields.

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Genomic selection in Gir cattle using female reference population

Nayee

Gajjar

Sudhakar

et al. 2021

Indian J of Anim Sci

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When a sizeable reference population of proven bulls is not available for implementing Genomic selection for a particular trait, and when a recording of certain traits on large scale is difficult, the use of a female reference population is recommended. Gir, one of the important milk purpose cattle breeds of India falls under this category. There is no large scale Progeny Testing (PT) programme in Gir, so proven bulls based on daughter performance in large numbers are not available. Considering the constraints, a genomic BLUP (GBLUP) model was implemented based on recorded cow reference population in Gir breed. Cows (3491) and 23 bulls were genotyped using INDUSCHIP for this purpose. Due to non-availability of pedigreed data, conventional breeding values (BV) of bulls and their reliabilities were not known. For comparison, assumed theoretical reliability of BV of a bull selected based on its dam's yield was compared with reliability obtained for genomic breeding value (GBV) using a GBLUP model. The reliability estimates for GBVs were 4 times higher than that for BVs. The predictive ability of the model was demonstrated by measuring the correlation between corrected phenotypes and GBVs for animals whose records were masked in a five-fold cross-validation study. The correlation was around 0.45 showing reasonable predictability of the GBLUP model. The GBVs were not biased. The regression coefficient between the corrected phenotype and GBV was 1.045. The present study demonstrates that it is feasible to implement genomic selection in Gir cattle in Indian conditions using a female reference population. It is expected that the bulls can be selected with around 4 fold more accuracy than the current method of selecting based on their dams' yield accelerating expected genetic growth in Gir cattle.

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Estimativas de Parâmetros fenotípicos e ambientes das Produções de Leite no Dia do Controle e em 305 Dias de Lactação em vacas da Raça Gir

Cited by 3 publications

References 7 publications

Genetic parameters for test-day milk yield, 305-day milk yield, and lactation length in Guzerat cows

Genetic parameters for test-day milk yield, 305-day milk yield, and lactation length in Guzerat cows

Genetic parameters for milk, fat and protein yields in Murrah buffaloes (Bubalus bubalis Artiodactyla, Bovidae)

Genomic selection in Gir cattle using female reference population

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