Factors affecting survival traits in dairy industries of Esfahan

Today, survival and longevity are important issues and popular among dairy cattle breeders . The reason is unreasonable rate increase involuntary remove dairy cows in many herds . In addition, the cost of removal and replacement of cattle losses due to discarding milk cows with the disease are high. To study the survival traits of different definitions, this research project through data collected related to the years 1366 till 1382 the original level of 35 Holstein dairy cattle . Information includes number of animal, Issue father, Issue mother, date of birth removed since the age first calving number of courses lactation milk and fat corrected . Then, using data longevity traits, productive life and lifetime performance was calculated. The average lifetime was 1878.4 ± 703.7 days and the average lifetime production was 1067± 701.7 and longevity was 1070 ± 700.1. In other words, every cow automatically after approximately three abdominal delivery has been deleted. Regression coefficient lifetime production of milk production equal to 0.102. Effects of herd, year, season and age of first calving highly significant effect (p 0 / 01) . Comparison test of Duncan's method (statistical level of five percent) shows that the maximum difference between longevity and lifetime production and longevity-related functional cows that winter and autumn have the least amount of related to the cows that in the spring and summer seasons have delivery. In recent years, the mean milk production increase, but survival rates is a decline. The effect of age at first calving with lifetime production had an inverse relationship. So that each one day increase in age of first calving, productive life 0.26 day and lifetime performance of 0.20 day decreases. Heritability coefficient for each shelf life characteristics, productive life and lifetime performance were 0.02 ± 0.01 and 0.019 ± 0.01 and 0.021 ± 0.01, respectively. Genetic correlations between lerd life and length of production were estimated one.