This 4-yr study was conducted with Angus (A)-sired and Polled Hereford (PH)-sired crossbred heifers that were exposed to either A or medium-frame Brahman (B) bulls from primiparous calvings either as 2- or 3-yr-olds. Each year, heifers were allotted at random within breed composition and age of dam to breeding groups on pasture for an 84-d breeding period that began in late March or early April...

Two factors presumed to affect the behavioural response of cattle (Bos taurus) to artificial weaning were investigated: the termination of nursing, and the physical separation of cows and calves. A two-stage process was used to disconnect these traditionally linked components. First, the behaviour of cows and calves was quantified in response to preventing nursing by having calves wear an antis...

Studies were conducted to evaluate the effect of early weaning steer calves on BW gain, feedlot performance, and carcass characteristics in two herds located in the Northern Great Plains, USA. Steer calves from predominantly Angus Hereford dams were stratified within dam age and calving date (Fort Keogh Livestock and Range Research Laboratory (LARRL), Miles City, MT, USA; n1⁄4354) and randomly ...

Calves weaned on cow­calf operations throughout Arkansas even­ tually move on to stocker, feedlot and packer operations. Wide variations in carcass uniformity and consistency exist among these calves. Potential carcass problems can include inappro­ priate carcass size and weight, i nadequate tenderness, insufficient intramuscular fat (marbling) and excess external fat cover. Many of these quali...

A study was conducted evaluating the effect of long-term Cu deficiency, with or without high Mn, on growth, gene expression and Cu status of beef cattle. Twenty-one Angus calves were born to cows receiving one of the following treatments: (1) 10 mg supplemental Cu/kg DM (+Cu); (2) no supplemental Cu and 2 mg Mo/kg DM ( - Cu); (3) - Cu diet plus 500 mg supplemental Mn/kg DM ( - Cu+Mn). Calves we...

Twenty-four Angus x Holstein heifers were utilized in the single-calf heifer system. Calves were weaned from one-half of the dams between d 64 and 89 postpartum. Dam’s were gradually adapted to a high concentrate diet over a four wk period at the beginning of the trial. Heifers that had their calves early weaned (EW) gained 44.2% faster (P < .01) and consumed 10.8% less (P < .05) DM than lactat...

Calfhood diseases have a major impact on the economic viability of cattle operations. A three part review series has been developed focusing on calf health from birth to weaning. In this paper, the last of the three part series, we review disease prevention and management with particular reference to pneumonia, focusing primarily on the pre-weaned calf. Pneumonia in recently weaned suckler calv...

The objective of this study was to investigate the effects delayed increase in milk allowance and type gradual weaning program on feed intake, health, growth male Holstein calves. Using a 2 × factorial design, each calf randomly assigned 1 level treatments upon arrival rearing facility. Calves were either moderate (MM) or lower (LM) treatment. All calves received same from until d 12, increasin...

Duodenal flow of microbial N (MN) was estimated from urinary purine derivatives to examine age-related changes in MN in male Holstein calves. In Exp. 1, endogenous purine derivatives were determined by measurement of purine derivatives in five calves fed nucleic acid-free milk replacer alone. In Exp. 2, the ratio of urinary excretion as purine derivatives to purines administered via the reticul...

Fifteen weaned calves (age 89-141 days) were treated with dexamethasone (0.25 mg/kg, IV) for 3 days before, the day of, and the day after inoculation with 10 colony-forming units of either Escherichia coli O157:H7 (strain 86-24, which produces Shiga toxin 2 and intimin; n = 13) or nonpathogenic E. coli (strain 123, which does not produce Shiga toxin or intimin; n = 2). All calves were necropsie...