Estimation of nonadditive genetic impacts on lifetime performance through a grading-up breeding program with Holstein-Friesian

Abstract

The aim of this study was to estimate the total lifetime milk production and non additive genetic effects (recombination and heterosis) of cows with different proportions of Holstein-Friesian genes, obtained from the Serbian Fleckvieh (SF) and the Holstein-Friesian (HF) crossbreeding program in Vojvodina. Upgrading of local breeds with the Holstein-Friesian breed in Vojvodina started in 1971 and continued 2008. Six genotypes of cows (F 1 , R 1 , R 2 , R 3 , R 4 , R 5 ) were obtained with increasing percentage of Holstein genes, in order to attain purebred Holstein cows. Of all obtained genotypes, cows of genotype R 4 with a proportion of Holstein genes from 96.87 % had the highest lifetime milk production (20000 kg), followed by cows R 3 with 19950 kg (93.75 % HF genes) and cows R 5 with 19850 kg (98.44 % HF genes). Finally the process of upgrading resulted in pure Holsteins with 19780 kg of milk. The total lifetime production of milk fat did not show statistically significant difference (P>0.05) among the genotypes R 1 -R 5 which ranged from 675 to 690 kg. The pure Holstein obtained after sixth intermediate generations had the average lifetime milk fat production of 690 kg. With the increase in the proportion of Holstein-Friesian genes percentage of milk fat was decreased, so that the cows of genotypes R 3 , R 4 , R 5 and pure Holsteins, had less than 3.5 % milk fat. In relation to the total milk yield, the highest realized heterosis effect was observed in the cows of F 1 generation ( =594 kg), while the lowest was observed in generation R 2 ( =72 kg), where negative effect of recombination was also found ( =-77 kg). Positive values of the actual and relative of heterosis effect of the milk fat yield was observed in all genotypes, whereas the negative heterosis effect of the milk fat percentage was observed also in all genotypes, with the exception of R 1 and R 2 cows, in which the typical consequence of the positive recombination in the early crossed Holstein-generations was manifested.

Breed, heterosis, and recombination effects for lactation curves in Brazilian cattle

“…An index including 305-day milk yield, peak yield, persistency of milk yield, and other economic traits of interest could be studied to introduce genes in Girolando cattle by crossbreeding. Nemes et al (2014) reported that a planned crossing leads to an optimal gene recombination, resulting in increases in production and maintenance of the variability necessary for a continuous positive success of selection of the observed properties. However, a negative recombination effect was found in the present study for all traits, except for LP and time to peak (TP, TP WD , and TP WL ).…”

“…Most studies report negative values for the recombination effect (Madalena et al, 1990;Nemes et al, 2014;Birhanu et al, 2015). Facó et al (2008) reported significant and negative recombination effects for MY and MY 305 traits in Holstein × Gyr crossbred cows, indicating that the gene recombination observed in some types of crosses produces depressant effects on milk production.…”

Avaliação de diferentes modelos para estimar valor genético em características que compõem o índice de seleção em bovinos compostos

“…Ao se misturar muitos cromossomos de origens diferentes, os organismos passam a misturá-los e formar novos cromossomos homólogos no fenômeno do crossing over que pode ocorrer nas células gaméticas e transferir para a próxima geração a recombinação genética (CARROLL, 2013;MATHER, 1938). O que é um efeito economicamente ruim a curto prazo, por trazer perdas na capacidade produtiva de certas características em diversas espécies de interesse comercial (DALTRO et al, 2021;MADALENA et al, 1990;NEMES et al, 2014), porém esta perda de produção é justificável ao se avaliar no longo prazo que ela permite um aumento da variabilidade genética dentro da população sem a inserção de novos indivíduos (BATTAGIN et al, 2016;GORJANC et al, 2017). Evitando dessa forma resultados indesejáveis como o efeito Bulmer (BULMER, 1971), que ocorre ao se focar em uma gigantesca propagação de material genético dos poucos touros superiores, reduzindo o tamanho efetivo da população (SHEN et al, 2018) e aumentando a endogamia.…”