the objective of this study was to investigate the effect of birth weight (bw) on future milk production and reproductive performance in iranian holstein cattle. records of holstein cows between 1967 and 2010 were obtained from the animal breeding center of iran. birth weights within each herd were grouped into five categories based on the standard normal distribution curves (z ≤-0.8416, -0.841...

The association of birth type (single vs. double) and pregnancy type (single vs. double) with lactation performance and lactation curve was investigated in Holstein cows in Iran. Data of 243298 lactations on 138021 cows in 261 herds collected during January 2000 to December 2012 were used. The average twinning rate was 3.64% and ranged from 1.44% (primiparous) to 5.41% (multiparous). Factors as...

Milk yields were measured every 6 weeks from 21220 days after calving in either moderate or low conditioned groups of Angus, Angus x Friesian or Simford first-calf heifers for 3 successive years. Day of peak yield, peak yield and total 220 day yield were calculated by fitting 3 published equations to data on each of the breed x year x calving condition combinations. All equations ranked breed a...

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...

this study was conducted to evaluate the effects of extruded linseed on milk production, dry matter intake and reproduction performance of 300 holstein lactating cows (35±15 days in milk; 41±9/8 kg/day of milk production). cows were utilized in a completely randomized experimental design, comprised of: 2 treatments (concentrate containing 7 percent extruded linseed vs control) with a number of ...

The objective of this study was to estimate effects of environmental sensitivity of milk production traits for several environmental parameters and to investigate the impact of combining traits with different environmental sensitivity in an economic index. Variance components and breeding values were estimated for milk, fat, and protein yield, and fat and protein percentage by applying a random...

the effects of monesin and propylene glycol on feed intake, milk production, and composition as well as some blood metabolites of 16 primiparous and multiparous holstein lactating cows (60±30 days in milk (dim), milk production of 33±3 kg/day) were evaluated. cows were experimentally in a arranged in a randomized complete block design of: 4 feeding treatments, and 2 blocks of either primiparous...