Phenotype correlations of linear assessment scores of type and production traits of simmental cows

Abstract

Determining the degree of correlation between two or more traits depends to a large extent on their manifestation. The knowledge of genetic and phenotypic correlations between body characteristics of the animal and product characteristics can help define the breeding goal, but also to define and harmonize the assessment criteria. Although the phenotypic and genetic correlations between the traits of body development and type and the milk yield show different degrees of variation, they should be taken into account in the final assessment of the breeding value of the animal so that the selection programs are more comprehesively defined. The examination of phenotypic correlations of linear assessment scores of the type, milk and fertility traits was performed on a total of 303 cows of the Simental breed in the first three lactations. The examination of phenotypic correlations included the following milk performance properties in the first three standard lactations: milk yield, milk fat content, milk fat yield, yield of 4% corrected milk; also fertility traits: age at current calving and service period in each lactation; while the linear type scoring included a group of traits: type or frame, muscularity, fundament, udder.

Poznavanje fenotipske povezanosti osobina mlečnosti i plodnosti, sa linearnim ocenama tipa je veoma značajno u selekcijskom radu, gde se pored visoke proizvodnje, očekuje dobro zdravlje kao i dug produktivni život grla u stadu. U ovom istraživanju medjusobna pozitivna i potpuna fenotipska povezanost prinosa mleka, mlečne masti i 4% mast korigovanog mleka ustanovljena je u sve tri laktacije, kao i niska i uglavnom pozitivna povezanost pokazatelja prinosa i sadržaja mlečne masti. Niska i uglavnom pozitivna fenotipska povezanost utanovljena je u sve tri laktacije i za pokazatelje mlečnosti i plodnosti, ali i za pokazatelje plodnosti i tipa. Fenotipska povezanost pokazatelja mlečnosti i prosečnih ocena tipa je bila srednje jaka i uglavnom pozitivna za osobine prinosa i slaba i uglavnom negativna izmedju osobina tipa i sadržaja mlečne masti. Fenotipska povezanost ispitivanih osobina pokazuje da se prilikom odabira kako priplodnih junica, tako i semena za oplodnju krava i junica, mora povesti računa i o tipskim karakteristikama, jer će to pored odabira po mlečnosti doprineti ostvarenju veće proizvodnje mleka i bržem genetskom unapredjenju naše populacije.