Milk yield per cow has more than doubled in the previous 40 years and many cows now produce more than 20,000 kg of milk per lactation. The increase in production should be viewed with concern because: i) the increase in milk yield has been accompanied by declining fertility, increasing leg and metabolic problems and declining longevity; ii) there are unfavourable genetic correlations between mi...

Positional, comparative candidate gene analysis and previous quantitative trait loci linkage mapping results were used to search for candidate genes affecting milk production and reproduction traits in dairy cattle. The protease inhibitor (PI) gene was chosen for examination, and 5 single nucleotide polymorphisms were detected in coding regions of the gene by direct sequencing of reverse transc...

A genome scan was conducted in two US Holstein half-sib families to identify quantitative trait loci (QTL) affecting milk production and conformation traits using the granddaughter design. The sires of the two studied families were related as sire and son and had 96 and 212 sons respectively. A total of 221 microsatellite loci were scored in both families. Statistical analysis was performed usi...

Inheritance of economic traits was studied in Nili-Ravi dairy buffaloes through analysis of data comprising 5037 records of daughters of 79 sires. Data were collected from three large-sized state dairy farms. Heritability, genetic and phenotypic correlations of some indicator traits on important production and reproduction traits were worked out. Based upon analysis of records for first lactati...

Daily milk, fat and protein yield and amount of somatic cells in cow milk are very important factors that influence milk performance traits. An association between polymorphisms in the kappa casein (CSN3) gene and milk production, composition and technical properties has been previously reported; however, this type of information is not available for the bovine β-carotene oxygenase 2 (BCO2) gen...

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...

We have exploited “progeny testing” to map quantitative trait loci (QTL) underlying the genetic variation of milk production in a selected dairy cattle population. A total of 1,518 sires, with progeny tests based on the milking performances of > 150,000 daughtersjointly, was genotyped for 159 autosomal microsatellites bracketing 1645 centimorgan or approximately two thirds of the bovine genome....

Market failures are the main cause of poor acknowledgement of the true impact of functional sheep traits on the management and economic performance of farms, which results in their omission from the breeding goal or the estimation of non-representative economic weights in the breeding goal. Consequently, stated-preference non-market valuation techniques, which recently emerged to mitigate these...

KADLECOVA, V., D. NEMECKOVA, K. JECMINKOVA and L. STADNIK, 2014. The effects of polymorphism in the DgAt1 gene on energy balance and milk production traits in primiparous Holstein cows during the first six months of lactation. Bulg. J. Agric. Sci., 20: 203-209 The aim of this study was to analyze the effects and significance of DGAT1 K232A polymorphism on milk production traits – milk yield, co...