background: the osteopontin (opn) is a highly phosphorylated glycoprotein in numbers of bovine tissues and milk. opn has been reported to be associated with milk production in cattle.objective: the genotype and allelic frequencies for opn and its association with milk production will be evaluated in iranian holstein bulls.  materials and methods: bulls dna (100) was isolated. oligo was used for...

data related to yazd native fowls (obtained during 2000-2008) yazd native fowls were made use of in the present study. the investigated traits consisted of body weight at 8 (bw8) and 12 weeks (bw12), age at sexual maturity (asm), egg number during the first three months of production period (en) and the mean egg weight at 28, 30 and 32 weeks of age (ew). the genetic and phenotypic parameters we...

For more than half a century, progeny testing has been the foundation of genetic selection programs in dairy cattle (Robertson and Rendel, 1950). Several factors make progeny testing especially advantageous in dairy cattle, most notably widespread use of artificial insemination (AI) with frozen semen and the fact that nearly all traits of economic importance, including milk production, milk com...

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...

Mixed model techniques were used to evaluate the importance of cytoplasmic genetic effects on beef cattle performance. Birth weight (BWT), preweaning average daily gain (ADG), weaning weight (WT205), postweaning gain (PG), ultrasonic backfat thickness (FAT) and predicted milk yield (MILK) data were collected in two herds of Hereford cattle located at Plymouth and Raleigh, North Carolina. Cytopl...

Genetic trends for 305-day milk yield (P305) in Brazilian Guzerat herds under selection were compared. Data from 4898 lactations of 3179 purebred and crossbred cows from various regions of Brazil were used. Milk yield was adjusted for mature age and the contemporary groups were defined as herd and calving year. Genetic parameters were estimated using the MTDFREML program. The model included the...

The objective of this study was to analyze the correlation between Holstein body conformation traits and milk production traits in the Shanghai region. In total, 871 Holstein cows were randomly chosen from 28 dairy farms in Shanghai at second stage of lactation as the object of our study. Five milk production traits, including 305-d milk yield, butter fat percentage, milk protein percentage, pe...

the objective of this study was to determine the polymorphism of bovine β-lactoglobulin (β-lg) gene and its association with milk production traits in iranian najdi cattle. blood samples were collected from 80 najdi cattle from the najdi cattle breeding station located in shoshtar, khuzestan. polymerase chain reaction (pcr) and restriction fragment length polymorphism (rflp) techniqus were used...