Twinning in Holstein dairy cows has increased over time concurrent with increased milk production. More than 95% of twins in Holsteins arise due to double ovulations resulting in dizygotic twins. It is now clear that low progesterone during growth of a preovulatory follicle increases the incidence of double ovulation. Increased hepatic metabolism of progesterone as a result of the increased fee...

In pasture-based seasonal calving systems, failure to become pregnant during the breeding season results in important economic losses as maximum profit is attained by minimising costs and increasing the proportion of grass in the diet of the lactating dairy cow. In the United States, dairy producers primarily strive to maximise production potential but are becoming increasingly aware of the eco...

Effects of Monensin on Dry Matter Intake, Milk Production and Healthy Transition Holstein Dairy Cows

fungal infection of uterine of dairy cattle have not been received much more attention. the aim of this study was: to investigate the uterine mycoflora of dairy cows with reproductive disorders or healthy. uterine sampling of 112 holstein dairy cows included 70 cows with reproductive disorders and 42 healthy cows were collected directly. samples were cultured in sabouraud glucose agar at 28°c f...

This study utilized daily records of 2000 Egyptian Holstein dairy cows. The productive, reproductive and economic data during a whole lactation season were recorded for healthy and mastitis cows. Two risk factors for mastitis were included, parity and season of calving. Mastitis cows had significant (P

electrocardiography (ecg) may be used to recognize cardiac disorders. levels of milk production may change the serum electrolytes which its imbalance has a role in cardiac arrhythmia. fifty high yielding and fifty low yielding holstein dairy cows were used in this study. electrocardiography was recorded by base-apex lead and blood samples were collected from jugular vein for measurement of seru...

Association Between β-Defensin Gene Polymorphism and Clinical Mastitis in Holstein Dairy Cows: A Case-Control Study

A survey was conducted to quantify incidence of Beef Quality Assurance (BQA)-related defects in market beef and dairy cows and bulls selling at auction during 2 seasons in 2008. Twenty-three BQA-related traits were evaluated by 9 trained personnel during sales at 10 livestock auction markets in Idaho (n = 5; beef and dairy), California, (n = 4; dairy only), and Utah (n = 1; beef and dairy). Ove...

In this study, the relationships and correlations between milk production and some blood metabolites related to energy and protein balance and their effects were investigated on returning to estrus after AI in lactating Holstein dairy cows. Blood and milk samples were collected from sixty lactating Holstein dairy cows based on their reproductive status in 13-17 d post AI. BUN, MUN, glucose, tri...

in this study, the incomplete gamma function, an exponential function, a mixed-log function and a polynomial function were evaluated to describe the lactation curve in moroccan holstein-friesian dairy cows. data from 1990 to 1999, comprising 77130 monthly milk yields of 6029 dairy cows in 280 dairy herds, were used. edits were carried out by considering the lactation length (5 d and