Genetic evaluation of dystocia and its relationship with productive and reproductive traits in Holstein cows

Abstract

Evaluación genética de distocia y su relación con las características productivas y reproductivas en vacas HolsteinAvaliação genética de distocia e sua relação com características produtivas e reprodutivas em vacas da raça Holandesa Abstract:Background: dystocia is one of the most economically significant secondary traits in dairy cows and has adverse effects on the subsequent survival, health, and performance of mothers and offspring. Objective: the aim of this study was to estimate direct and maternal genetic parameters for calving ease (CE) and its relationship with productive and reproductive traits in Iranian Holstein cows. Methods: data from 1991 through 2011 were collected from the Animal Breeding Center of Iran, and contained 132,831 records of CE, 183,203 records of productive traits including 305-d adjusted milk yield (MY305), 305-d adjusted fat yield (FY305) and 305-d adjusted protein yield (PY305), and 129,199 records of reproductive traits including days open (DO), days to first service (DFS) and calving interval (CI). Univariate and bivariate linear animal models were used for the analysis of traits in two different models on which direct genetic effect (model 1) and direct + maternal genetic effects (model 2) using AI-REML algorithm were included. Results: estimated heritabilities for CE in model 1 were 0.02 in univariate and 0.02-0.03 in bivariate analyses. Direct and maternal heritabilities in model 2 were 0.02 and 0.002 for univariate, and 0.03 and 0.0004-0.006 in bivariate analyses, respectively. Genetic correlations between direct effects of CE with MY305, FY305, and PY305 were -0.99, 0.02 and -0.07 in model 1, and -0.2, -0.02 and -0.13 in model 2, respectively. Conclusion: this study suggested that a selection index that includes both direct and maternal effects should be included in CE breeding programs.

Restricted Selection Index to Relieve the Negative Repercussion in Reproductive Performance of Holstein Cows

“…These results reflect the major effect of environmental conditions on reproductive traits. Similar trend of phenotypic variability has been found in several previous studies (Salem and Hammoud 2016a;Salem and Hammoud 2016b;Ayalew et al 2017;Frioni et al 2017;Salimi et al 2017). The lower variability in productive traits compared to reproductive traits indicates a high homogeneous population in these traits which may be as a result to lower culling of cows with progressing through the first three parities.…”

“…The h 2 estimate of DO (0.08, Table 1) was within the range of 0.03 to 0.12 as reported in literature (Guo et al 2014;Yamazaki et al 2014;Faid-Allah 2015;Ben Zaabza et al 2016;Radwan and Abo Elfadl 2016;Ayalew et al 2017;Salimi et al 2017) and lower than the values of 0.15 and 0.18 as reported by Radwan and Abo Elfadl (2016) and Salem and Hammoud (2016a), respectively. Heritability of CI (0.06, Table 1) was slightly lower than the estimates of 0.09 and 0.11 as reported by Zambrano and Echeverri (2014) and Ayalew et al (2017), respectively and within the range of 0.002 to 0.07 as stated in other previous reports (El-Bayoumi 2015;Ben Zaabza et al 2016;Salimi et al 2017). The negligible h 2 estimate for NSPC (0.03, Table 1) is in agreement with the previous estimates ranged between 0.03 to 0.07 (Guo et al 2014;Yamazaki et al 2014;Ben Zaabza et al 2016).…”

Partial Restricted Selection Indexes to Fix the Length of Days Open in High – Yielding Dairy Cows

“…Faid-Allah (2015) gave much lower value (6384.95kg) for this trait. The value of 268.89kg for FY in present work (Table 1) was higher than the two values of 246.73 and 227kg reported under the Iranian conditions, respectively by Salimi et al (2017) and Behzadi et al (2013), and much higher than the value of 187.3kg reported by Frioni et al (2017) under Uruguay conditions. 1), it was found to be much higher than the value of 113.1 days recorded by Radwan and Abo-Elfadl (2016) and lower than the value of 219.5 found by Salem and Hammoud (2016b).…”