Phenotypic and genetic parameters of reproductive traits of black and white cows with different share of HF genes

Abstract

In this paper, results of the effect of direct and indirect selection of quantitative fertility traits of cattle end heritability level are presented. Study of the quantitative genetic parameters was carried out on three large farms of Black and White, Holstein-Friesian cattle. Investigation included 3900 first calving cows, daughters of 54 bull sires. The effect of genetic group of the head of cattle (genotype) and of the herd on fertility and milk traits of heifers and first calving cows of Black and White breed was investigated. Genetic group of the head of cattle (genotype) had no significant effect in variation of the fertility traits compared to general average (P (lt) 0.01). The effect of herd caused statistically significant and highly significant deviation from the general average, P (lt) 0.05 and P (lt) 0.01. Established heritability coefficients for fertility traits had low values for age at insemination (0,112), duration of pregnancy (0,045) and duration of service period (0,097). Results were obtained by applying mathematicalstatistical analysis of data - using mixed model (Harvey, 1990). Mathematical-statistical analysis of data was carried out using linear methods with fixed influence through model of Least Squares (LS method). Genotype of the head of cattle caused no significant deviation of fertility traits (P>0,05).

U ovom radu su predstavljeni rezultati uticaja direktne i indirektne selekcije na kvantitativne osobine plodnosti goveda i nivo heritabiliteta. Ispitivanje kvantitativnih genetskih parametara je izvedeno na tri velike farme gde se gaje crno-bela, holštajn-frizijska goveda. Ispitivanje je uključivalo 3900 prvotelki, kćeri 54 bika-očeva. Ispitivan je uticaj genetske grupe grla goveda (genotip) i zapata na osobine plodnosti i mlečnosti junica i prvotelki crno-bele rase. Genetska grupa grla goveda (genotip) nije imala signifikantan uticaj na variranje osobina plodnosti u odnosu na opšti prosek (P (lt) 0.01). Uticaj zapata je izazvao statistički signifikantno i visoko signifikantno odstupanje od opšteg proseka, (P (lt) 0.05) and (P (lt) 0.01). Ustanovljeni koeficijenti heritabiliteta za osobine plodnosti su imali niske vrednosti za osobine uzrast pri prvoj inseminaciji (0,112), trajanje bremenitosti (0,045) i trajanje servis perioda (0,097). Rezultati su dobijeni primenom matematičko-statističke analize podataka - korišćenjem mešovitog modela (Harvey, 1990). Matematičko-statistička analiza podataka je izvršena korišćenjem linearnih metoda sa fiksnim uticajem kroz model najmanjih kvadrata (LS metod). Genotip grla goveda nije izazvao signifikantno odstupanje osobina plodnosti (P>0,05).