Phenotypic and genetic correlations of milk and type traits of Holstein-Friesian bull dams

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.

Ispitivanje proizvodnih kapaciteta goveda u cilju povećanja proizvodnje mleka, mlečne masti i broja teladi, u velikoj meri zavisi od fenotipske i genetske varijabilnosti, heritabiliteta i povezanosti poželjnih osobina, kao i nivoa proizvodnje u populaciji. Cilj ovih istraživanja bio je da se u nukleus zapatu bikovskih majki holštajn frizijske rase primenom linearnog metoda ocenjivanja krava izračuna varijabilnost, fenotipska i genetska povezanost osobina mlečnosti i tipa, i njihov značaj u selekciji goveda. Za sve ispitivane osobine primenom metoda najmanjih kvadrata izračunati su osnovni varijaciono-statistički parametri: aritmetička sredina, standardna devijacija, koeficijenti varijacije, standardna greška i interval varijacije. Negativne fenotipske korelacije između proizvodnje mleka i osobina tipa kretale su se u intervalu od -0.12 (položaj zadnjih nogu sa strane) do -0.01 (visina krsta i dubina tela), a pozitivne od 0.03 (položaj zadnjih sisa) do 0.23 (centralni ligament). Fenotipske korealacije između procenta mlečne masti i osobina tipa kretale su se u intervalu od -0.08 (pozicija prednjih sisa) do 0.14 (visina krsta). Negativne genetske korelacije između proizvodnje mleka i osobina tipa varirale su u razmaku od -0.11 (visina zadnjeg vimena) do -0.01 (širina karlice i mlečne karakteristike), a pozitivne od 0.03 (položaj zadnjih nogu otpozadi) do 0.23 (centralni ligament). Genetske korealacije između procenta mlečne masti i osobina tipa kretale su se u intervalu od -0.15 (položaj karlice) do 0.18 (visina krsta). Postojanje informacija o fenotipskim i genetskim korelacijama između osobina mlečnosti i tipa, može imati višestruki značaj u selekciji krava, jer pruža mogućnost odabira grla na više osobina istovremeno.