Estimation of heritabilities, genetic correlations, phenotypic correlations and genetic trends for production and reproduction traits of Holstein-Friesian dairy cattle using sire model

Abstract

A total of 3460 lactation records that represented 1059 dairy Holstein-Friesian cows were used in the present study that aimed to estimate genetic parameters such as heritability, genetic correlations, phenotypic correlations and genetic trends for some productive and reproductive traits. Studied traits were total milk yield, days in milk, fat %, protein %, dry period, age at first calving, number of services per conception, days open and calving interval. Data were collected from Egyptian Copenhagen Company in Alexandria-Cairo desert road for cows calved from 1998 to 2010. Least square analysis of mixed sire model was used in analysis using Harvey (1990) program. Heritability estimates were high for all traits and very high for fat and protein % that exceeded 0.83 in two lactations. Genetic correlations were higher than phenotypic correlations and were high especially among production traits. Regression coefficients of genetic trends were positive for all studied traits except for days in milk and days open (in second lactation) and age at first calving. Generally, the current results showed genetic improvement of most of traits that reflect the efficiency of selection programs.

Epigenetics TREND for some Productive and Reproductive Traits of Friesian Cattle Raised in Egypt

“…was 0.002 . These results disagree with the finding of (Ghiasi et al 2011) and (Osman et al 2013) (Table.3) who found the heritability of services per conception within the range from 0.02 to 0.08. The results indicate that genetic improvement of these traits can be achieved through selection for these traits in breeding programs.…”

“…The average number of services per conception (NSC was 1.7 this values is similar to (Ihlam et al 2012) was found to be 1.9 .Mean of NSC found is less than a study by (Osman et al 2013) estimate were 2 in the first lactation while 3.5 on the second lactation.…”

“…Low h2for NCS in the present study due to the low percentage of the genetic effect of the h2, as this is affected by environmental factors through improvement managerial strategy procedures and nutritional. The same result were report by (Ihlam et al 2012) and (Osman et al 2013).…”

Estimate of Genetic and Phenotypic Trends for Some Productive and Reproductive Traits of Friesian Cows in Egypt

“…In parallel, Hammoud et al, (2014) reported the genetic and phenotypic correlation at low, medium and high level milk production between CI, 305-DMY was (r g =0.48, r p =0.70), (r g =0.82, r p =0.06) and (r g =0.75, r p =0.20), respectively. Additionally, Osman et al, (2013b) clarified positive genetic and phenotypic correlations in Holstein cows at the first parity between DO and LP (r g =0.990, r p =0.771) and positive correlations at the second parity were observed between LP and DO (r g =0.298, r p =0.544). The genetic and phenotypic correlation between LP and DO were positive (r g =0.037, r p = 0.406); 305-DMY and LP were positive (r g =0.037 and r p = 0.406) and 305-DMY and DO (r g = -0.005 and r p = 0.413) as mentioned by Faid Allah (2015).…”

“…Osman et al, (2013a) conducted heritability estimates of calving interval were 0.18 for second lactation at his studio on Holstein-Friesian dairy cattle. El-Shalamani (2011) reported heritability estimate of DO was 0.42 and Hammoud (2013) showed the values of DO was 0.48 for first lactation Holstein cows and Osman et al, (2013b) conducted heritability estimates at first parity of DO was 0.313 for Holstein cows and at second parity was 0.117. The difference in heritability estimates among various studies for the same trait could be attributed to differences in the number of records used, the correction for different non-genetic factors, the model used and the methodology used for estimation (Abou-Bakr, 2009).…”