Abstract Bovine Respiratory Disease (BRD) is the most devastating disease affecting cattle producers in North America. Vaccines and antimicrobials are commonly used to prevent treat BRD. However, it still a growing problem. The four common BRD opportunistic pathogens, Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, Mycoplasma bovis, present upper respiratory tract of healthy a...

Abstract Monensin is an ionophore commonly fed to feedlot cattle increase feed efficiency (gain:feed ratio; G:F) typically by decreasing dry matter intake (DMI) when at the adopted dose of 33 mg∙kg DM-1. During receiving period often suppressed due management stressors, feeding monensin light-weight calves may be detrimental DMI and consequently growth performance. The objective this experiment...

Two experiments were conducted to evaluate the effects of rumen-protected PUFA supplementation on performance and inflammation measures in beef calves after truck transportation and feedyard entry. In Exp. 1, 30 weaned Braford steers (BW = 218 ± 4.3 kg) were transported for 1,600 km over a 24-h period in a commercial trailer and delivered to a feedlot (d 0). Upon arrival (d 1), steers were stra...

The surface of beef cattle feedlot pens is commonly conceptualized as being packed uncomposted manure. Despite the important role that the feedlot pen may play in the transmission of veterinary and zoonotic pathogens, the bacterial ecology of feedlot surface material is not well understood. Our present study characterized the bacterial communities of the beef cattle feedlot pen surface material...

Three fattening systems were evaluated from weaning to slaughter in order to find alternatives to grain feeding in young bulls, and to test the reliability of carcass subcutaneous fat colour to discriminate among them. After weaning (224 kg), one group of animals was fed concentrates and straw until they reached the target slaughter weight (450 kg; Feedlot), another group grazed rotationally on...

The aim of this study was to identify factors influencing profitability in a feedlot environment and to estimate genetic parameters for and between a feedlot profit function and productive traits measured in growth tests. The heritability estimate of 0.36 for feedlot profitability shows that this trait is genetically inherited and that it can be selected for. The genetic correlations between fe...

this study was carried out by using two hundred ewes (2-4 years old) as  pure breeding (zel × zel) and crossbreeding (chal × zel). in each treatment, 30 male and 30 female lambs were fattened in a feedlot experiment for three periods; 75, 100 and 125 days. at the end of each period, 10 lambs of each treatment were slaughter and carcasses analysis was down. the lean meat percentage and bone perc...