Breeds were compared for differences in BW (n = 56,731), heights (n = 51,407) and body condition scores (BCS, n = 56,371) of 2to 8-yr-old cows from four cycles of the Germplasm Evaluation (GPE) Program at the U. S. Meat Animal Research Center (MARC). Angus, Hereford, and topcross cows from 22 breeds of sires were produced. The mixed model for repeated measures of BW, height, and BCS included ra...

During an investigation of bovine brucellosis in Iran, conducted by the Razi Institute over a twelve-month period, samples of serum and milk were collected simultaneously from 6,472 cows in eight infected herds for serological and bacteriological testing. A total of 1,056 cows were serologically positive and 1,632 of 6,472 milk samples were positive to the milk ring test (MRT). Culture of the p...

Milk production is a primary factor controlling weaning weight of beef calves. The purpose of this experiment was to develop a practical and reliable on-farm method of estimating milk production and to relate estimates of milk production and milk composition to preweaning weight gain of calves. A second objective was to relate milk production to postpartum ovarian activity. Milk production of s...

Milk can be an attractive DNA-resource for genotyping milking cows, e.g. for paternity control or QTL analysis within a daughter design. The use of milk collected within the established milk evaluation programs enables the collection of large numbers of samples. Nevertheless, there are limitations when using the remedies of tested milk samples, e.g. permutations of samples or partially degraded...

The objective of this study was to evaluate the effect of ruminally protected amino acids (RPAAs) and ruminally protected fat (RPF) supplementation on ruminal fermentation characteristics (in vitro) and milk yield and milk composition (in vivo). Fourteen mid-lactating Holstein dairy cows (mean weight 653±62.59 kg) were divided into two groups according to mean milk yield and number of days of p...

Objective: The cows that don’t have access to sufficient energy in their ration can get sickness. Milk production has a high priority in metabolism of dairy cows so lactating cows are more prone to get sick This can ruin all the benefits of higher milk yield because of the higher prevalence of the disorders. Methods: Data for this research had gathered from a herd with 1600 Holstein cattle in E...

Twenty-four Holstein cows were used to study the effect of dietary fat on milk production and metabolic traits. Whole cottonseed and tallow were used as fat sources and substituted into the control diet on an isocaloric basis. Chopped alfalfa hay and grain sorghum silage constituted the forage in all diets. Treatments were balanced for parity, body weight, and previous lactation milk production...

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...

Calving records from April 1996 to December 2005 comprising 31863 calving events of 1173 dairy cows in a large commercial dairy herd were used to evaluate the effects of heat stress, using temperature-humidity index (THI) on milk yield and composition and reproductive performance of Holstein dairy cows under humid climatic conditions of Rasht in Iran. THI values were grouped into six groups: 30...

Effects of feeding grain and maize silage from a non-Bt maize and a variety of Bt maize that contains cry1F (event TC1507, event DAS-Ø15Ø7-1), a gene that provides maize with insect resistance, on the health and performance of dairy cows were evaluated. In a crossover trial, 20 lactating Holstein cows were assigned to each of 2 dietary treatment groups and fed diets containing whole-plant maize...