Several processes have been suggested to protect lipids from bioactivity of the rumen microorganisms. The majority of experiments with conjugated linoleic acid (CLA) were conducted using calcium salts of CLA. The objectives of this study were to determine the effects of encapsulated CLA (E-CLA) that was supplemented during days 21 to 100 post partum (PP), on milk fat depression, recovery rate a...

the genetic parameters for milk production and milk fat traits for first to third parities were estimated using single, multi trait and repeatability models. the genetic parameters for test day milk records were also estimated using random regression model. the test day records and 305 day milk records of 17055 cows from 10 herds collected between years 1996-2007 in khorasan razavi province wer...

First cut red clover-grass mixture sward were ensiled in two pits with inoculant (Lactobacillus rhamnosus + Propionibacterium freudenreichii ssp. Shermanii) and without any additives. Fermentation quality, nutrient losses and aerobic stability of silages were determined. The inoculated silage had no butyric acid, nutrient losses were lowered by 19.4%. In inoculated silage organic matter digesti...

Twenty-four multiparous lactating Holstein cows were blocked by days in milk and assigned to treatment sequences in a replicated 4x4 Latin square with 21-d periods. The four diets, formulated from alfalfa silage plus a concentrate mix based on ground high moisture ear corn, contained [dry matter (DM) basis]: 1) 20% concentrate, 80% alfalfa silage (24% nonfiber carbohydrates; NFC), 2) 35% concen...

Milk fat concentration is variable and very responsive to many factors including genetics, season of the year, and physiological state, but is especially responsive to diet. Synthesis of milk fat is an energy demanding process, but also represents a significant portion of the economic and nutritional value of dairy products. First described over one and a half centuries ago, diet-induced milk f...

This experiment was conducted to evaluate the effect of supplementing a fat diet with selenium (Se) and vitamin E on performance of cows, blood antioxidant status and milk fatty acid composition. Sixty-three lactating Holstein cows were randomly divided into seven groups of nine cows each and each group was fed one of the following diets: i) a basal diet (control); ii) a basal diet with 0.15 mg...

Four fistulated Holstein cows were arranged in a 4 x 4 Latin square design to study the effects of level and type of energy source on milk yield and composition. Treatments consisted of a basal diet fed alone (low energy treatment) or with 3.3 Mcal of net energy for lactation from extra nutrients perfused either into the rumen (either propionic acid or a mixture of volatile fatty acids) or into...

the aim of this study was to evaluate the effect of replacing progesterone injections by progesterone vaginal inserts on productive and reproductive parameters of lactating cows with reproductive problems after prolonged periods of heat stress. fifteen holstein cows were randomly assigned to one of three treatments: 1) treated with two progesterone vaginal inserts (p4-ins); 2) treated with prog...