Major objectives were to evaluate effects of three schemes of bST-supplementation of Holstein cows (142.8 mg/14 d, POSILAC) during the prepartum and/or postpartum periods through 63 d (±3 d) of lactation. Measures evaluated the potential of treatments to improve body weight (BW) and body condition score (BCS), provoke changes in plasma concentrations of somatotropin (ST) and IGF-I, and improve ...

The objective of this experiment was to evaluate the effects of bovine somatotropin administration on serum concentrations of glucose, insulin, NEFA, IGF-I, and progesterone (P4) in ovariectomized non-lactating dairy cows receiving exogenous P4, as a model to estimate treatment effects on hepatic P4 degradation. Ten non-lactating, non-pregnant, and ovariectomized Gir Holstein cows were assigned...

Five multiparous, ruminally cannulated Holstein cows (two lactating and three dry) weighing (X +/- SD) 667 +/- 35 kg were used to study the effect of abomasal purine infusion on the excretion of purine derivatives. Cows were fed corn silage four times daily at 90% of ad libitum intake (X = 9.16 kg of dry matter/d). Purines were infused into the abomasum as brewer's yeast suspensions in five inc...

The objective of this study was to compare the environmental impact of Jersey or Holstein milk production sufficient to yield 500,000 t of cheese (equivalent cheese yield) both with and without recombinant bovine somatotropin use. The deterministic model used 2009 DairyMetrics (Dairy Records Management Systems, Raleigh, NC) population data for milk yield and composition (Jersey: 20.9 kg/d, 4.8%...

The present study was designed to assess progesterone profiles at the secreted (caudal vena cava) and circulating levels (jugular vein) and luteinizing hormone (LH) secretion pattern in lactating and non-lactating cows with reference to feeding. Four lactating and four non-lactating cycling Holstein cows were examined. Blood samples were collected simultaneously from the caudal vena cava (via a...

The aim of this study was to determine the effect of different physical forms and urea treatment of rice straw on feed intake, rumen fermentation, and milk production. Four, multiparous Holstein crossbred dairy cows in mid-lactation with initial body weight (BW) of 409±20 kg were randomly assigned according to a 4×4 Latin square design to receive four dietary treatments. The dietary treatments ...

In the past decade, a global demand for products from organic agriculture has increased rapidly. Milk quality is of major interest for all parties. Therefore, the objective of this study was to compare cow performance and product quality in conventional and organic system. Twenty Holstein dairy cows were allotted to one of 2 diet groups, which including: a conventional diet (CON), and an organi...

Data from six experiments (two with dry cows) were used to predict partitioning of gross energy to CH4 in Holstein cows using selected independent variables, some of which were intercorrelated, and a stepwise backward elimination regression procedure. Methane outputs ranged from 3.1 to 8.3% (mean 5.5) of gross energy intake for 134 dry cow balance trials and from 1.7 to 14.9% (mean 5.2) of gros...

In order to characterize the expression of genes associated with immune response mechanisms to mastitis, we quantified the relative expression of the IL-2, IL-4, IL-6, IL-8, IL-10, IFN-γ and TNF- α genes in milk cells of healthy cows and cows with clinical mastitis. Total RNA was extracted from milk cells of six Black and White Holstein (BW) cows and six Gyr cows, including three animals with a...

Background: Metabolic profiles have been used in efforts to predict pre parturient problems and fertility, to diagnose metabolic diseases, and to assess nutritional status in dairy cows. These profiles may help to confirm the diagnosis of sub clinical diseases, to be aware of possible causes of infertility in the herds, or to monitor improvement in herd animals. OBJECTIVES: This study investiga...