Estimation of genetic parameters for female fertility traits in the Czech Holstein population

Abstract

Genetic parameters for fertility traits in Czech Holstein population were estimated. The database obtained from the Czech-Moravian Breeders Corporation with 6 414 486 insemination records between years 2005–2015 was used. Date of calving of the selected animals was taken from the database of milk records from 2005–2015. Fertility traits were age at first service (AFS), age at first calving (AFC), days open (DO), calving interval (CI) and first service to conception interval in cows (FSC-C) and heifers (FSC-H). The heritability of each trait was estimated using single-trait animal models. The model included fixed effects of herd-year-season of birth, herd-year-month of calving, lactation order, parity, last calving ease, linear and quadratic regressions on age at first insemination in heifers or on age at first calving in cows. Random effects were animal, permanent environmental effect and random residual error. After edits, the final data set included up to 599 901 observations from up to 448 037 animals dependent on traits. The range of heritability estimates was from 0.010 to 0.058. The lowest heritability was for first service to conception interval in heifers, and the highest heritability was for age at first service. Variances of random permanent effects were higher than variance of additive genetic effect in all traits manifested in mature cows. Repeatability ranged from 0.060 to 0.090. Genetic correlations between traits were estimated using a bivariate animal model. High positive genetic correlations were found between AFS–AFC, DO–CI, FSC-C–DO and FSC-C–CI. A moderate genetic correlation was found between AFS–FSC-H and between AFC. A negative correlation was found between AFS–FSC-C. Correlations between other traits were close to zero. The results suggest that the level of these reproductive traits can be improved by selection of animals with high genetic merit.

Genetic Assessment for some Productive and Fertility Traits Using Maximum Likelihood (REML) Of Friesian Cows in Egypt

“…However, it is higher than the means reported for the same breed in other countries (Salem et al, (2006), Rahbar et al, (2016), Chawala et al, (2017) and Brzakova et al, (2019).…”

“…But, the highest the means were 4.04 lactation and 5.26 lactation they reported by Salem and Hammoud (2019) and Khattab and Atil (1999). The overall mean of DO was 78 d. Higher estimates were reported by several other authors from different production environments ranged from 124.26 to 255 reported by (Abou-Bakr et al, (2000), Abou-Bakr et al (2006), Faid-Allah (2015), Rahbar et al, (2016) and Brzakova et al,(2019).…”

“…The heritability estimates obtained in this study for CI was 0.17. It is slightly higher than heritability estimates of 0.022 for Simmental Cattle in Turkey reported by Ulutas and Sezer (2009).However, lower estimates have been reported by many other authors from different production environments (Abou-Bakr, (2009) , Salem et al, (2006) , Rahbar et al, (2016) and Brzakova et al, (2019). The current estimates were higher than estimates of Ayalew et al, (2017) who used different models for analysis and decided that h 2 a estimate for CI was 0.11±0.04 from univariate, and 0.13±0.04 from two trait and three trait models.…”

“…However, slightly lower estimates were reported by several authors for Egyptian Holstein Friesian cattle where they reached (0.10 and 0.09±0.03)by Faid-Allah (2015) and Ayalew et al, (2017), respectively. On the other side, it is lower than heritability estimates of 0.38 for the Czech Holstein population by Brzakova et al, (2019). But, it is higher than heritability estimates of 0.02 in the north of Iran by Rahbar et al, (2016).…”

“…In the current study the repeatability (R) estimate for productive traits LTMY, DMY, LL, and LNC were 0.48, 0.51, 0.77 and 0.73 respectively, while were 0.42 and 0.24 for fertility traits DO and CI ,respectively (table 4). On the contrary, higher estimates of days open and calving interval have been reported in Ethiopian Holstein and Czech Holstein population by Ayalew et al, (2017) and Brzakova et al, (2019). However, lower estimates for LP of 0.31 in Friesian cows in Egypt by Salem et al, (2006).…”