Abstract
The study of the production capacities of cattleaimed at increase of the capacity of cattle to produce milk, milk fat and calves, greatly depends on pehotypic and genetic variability, heritability and correlation between preferable traits, as well as level of production in the population. Objective of the study was to calculate the variability, phenotypic and genetic correlation of milk and type traits by applying the method of linear scoring of cows in the nucleus herd of Holstein-Friesian bull dams and also to determine their significance in cattle selection. For all studied traits, main variation-statistical parameters were calculated by applying method of least squares: arithmetic mean, standard deviation, variation coefficient, standard error and variation interval. Negative phenotypic correlations between production of milk and type traits ranged from -0.12 (rear leg set, side view) to -0.01 (rump height and body depth) and positive from 0.03 (rear teat placement) to 0.23 (suspensory ligament). Phenotypic correlations between milk fat percentage and type traits varied in the range from -0.08 (fore teat placement) to 0.14 (rump height). Negative genetic correlations between milk production and type traits ranged from -0.11 (rear udder height) to -0.01 (rump width and dairy form), and positive from 0.03 (rear legs set, rear view) to 0.23 (suspensory ligament). Genetic correlations between the percentage of milk fat and type traits ranged from -0.15 (pelvic position) to 0.18 (rump height). Information about phenotypic and genetic correlations between milk and type traits can be of multiple significance in cow selection since it offers possibility to select heads of cattle for multiple traits at the same time.
Highlights
IntroductionGenetic correlations are very significant in direct or indirect selection where changes in one trait are induced by selection for another trait between which the genetic correlation exists
Genetic correlations are very significant in direct or indirect selection where changes in one trait are induced by selection for another trait between which the genetic correlation exists.Phenotypic correlation between milk and fertility traits is very significant for simulatanous selection for multiple traits, and even more significant for indirect selection in conditions when some traits cannot be improved directly
In case of absence of adequate dissemination of genetic progress from nucleus herd to the remaining population, all efforts made towards the improvement of certain traits and realization of set breeding program can be without success (Harris and Newman, 1994)
Summary
Genetic correlations are very significant in direct or indirect selection where changes in one trait are induced by selection for another trait between which the genetic correlation exists. Phenotypic correlation between milk and fertility traits is very significant for simulatanous selection for multiple traits, and even more significant for indirect selection in conditions when some traits cannot be improved directly. Linear type traits are basis of all modern classification systems, and represent foundation of all systems used for description of dairy cow. Linear classification is based on measuring/measurements of individual type traits rather than giving opinions on them. It describes the level of presence of certain trait, and not the level of desirability (Pantelić et al.2011)
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