The objective of this study was to analyze the association of somatic cell score (SCS) with milk, fat and protein yields across parities. Records of production traits and somatic cell counts (SCC) from first, second and third parity that were collected by the Animal Breeding Center of Iran from 1993 to 2010 were used.All animals were grouped into six classes according to SCC and production trai...

Intensive selection of sires is possible by using artificial insemination; coupled with accurate measurement of a potential sire’s genetic value, this has markedly improved genetics for easily measured traits like milk production and type traits. Increased milk production has in turn increased gross feed efficiency through dilution of maintenance. Additional genetic gains in feed efficiency wou...

The relationship between the SNP of the cytochrome P450 gene (CYP19-PvuII) and milk production traits of Black-and-White and Jersey cattle were analysed. A total of 437 cows were included in the study. A PCR-RFLP was used to genotype. The frequencies of genotypes and alleles for the Black-and-White cows were as follows: 0.8985 AA, 0.0977 AB, 0.0038 BB, and 0.9474 CYP19, 0.0526 CYP19. In the Jer...

BACKGROUND Despite the importance of relationships between somatic cell score (SCS) and currently selected traits (milk, fat and protein yield) of Holstein cows, there was a lack of comprehensive literature for it in Iran. Therefore we tried to examine heritabilities and relationships between these traits using a fixed-regression animal model and Bayesian inference. The data set consisted of 1,...

The dairy industry has made large advances in efficiencies over the past 60 years as a result of changes in breeding, nutrition and management practices [1]. To meet the growing demand for dairy products, which is projected to continue out to the year 2050 [2], milk production per cow has increased over the last thirty years primarily by genetic selection and better nutrition. Genetic selection...

Breed differences and nonadditive genetic effects for milk production traits, somatic cell score (SCS), conception rate (CR), and days to first service (DFS) were estimated for Holstein × Montbéliarde and Holstein × Normande crossbreds, using an animal model adapted from the French genetic evaluation and extended to across-breed analysis. Inbreeding and breed differences were estimated from all...

The aim of this study was to refine the position of previously detected quantitative trait loci (QTL) on bovine chromosome 14 affecting milk production traits, using both linkage analysis (LA) and combined disequilibrium and linkage analysis (LDLA) methods, in Iranian Holstein dairy cattle. Analysis data was LRT (likelihood ratio test) and computed using the DMU (estimate the (co)variance compo...

four hundered and ninety five (495) smallholder dairy farms active in 52 villages of different cities in chaharmohalo bakhtiari province, keeping 1321 lactating within a total of 2811 mature cows (lactating and dry) were used. these herds were taken during winter 2009 to summer 2010 to assess some of the production, reproductive and economic performance traits under smallholder management syste...

the present study was conducted to estimate genetic parameters and genetic, environmental and phenotypic trends of milk production traits in holstein cattle of hamedan province. in this study 11986 305-d records of first three parities of hamedan province holstein cattle, which were gathered during 1990-2011, were used. variance-covariance components and breeding values were estimated using ani...

dairy cattle breeding programs have been based in the selection for traits related to milk production. in this research a data set of 63 herds of east azerbaijan province holstein cattle, collected during 2002-2013 by the iranian animal breeding center was used to estimate the repeatability and heritability of three traits of economic importance. genetic parameters for first three lactations of...