M. E. Hubbert

Nutritional recommendations of feedlot consulting nutritionists: The 2015 New Mexico State and Texas Tech University survey

The 2015 feedlot consulting nutritionist survey is a collaborative project between New Mexico State University and Texas Tech University that focuses on summarizing the professional practices of consulting feedlot nutritionists and updates a 2007 survey. Forty-nine consulting feedlot nutritionists were asked to participate, of which 24 completed the survey. The nutritionists surveyed service over 14,000,000 cattle annually and were representatives from individual consulting practices (54.2%), corporate cattle feeding companies (20.8%), corporate feed manufacturing companies (20.8%), or a combination of consulting practices (4.2%). The survey was completed using a web-based survey tool and contained 101 questions that were divided into sections regarding general information about the consulting practice; general cattle management; receiving cattle management, diet adaption; mixers, feed mills, and feeding management; grains and grain processing; grain by-product use; roughage use; information about supplements and microingredients; liquid feed use; nutrient formulation; feed additive use; and information used as a basis for nutritional recommendations. In most cases, the results of the current survey were similar to those reported for the 2007 survey, with a few notable exceptions such as shifts in cattle numbers and preferences for specific feedstuffs. The present study introduced a number of new questions not included in the 2007 survey that focused on management strategies used in the receiving period. Data from this survey provide insight into current nutritional and management practices of consulting nutritionists and, as in past surveys, should be useful for informing national committees that make nutritional recommendations for cattle, as well as nutrition and management strategies employed within university research settings.

Effects of dietary urea concentration and zilpaterol hydrochloride on performance and carcass characteristics of finishing steers

Cattle receiving zilpaterol hydrochloride () may recycle less N and require a greater supply of RDP. This study evaluated effects of ZH on performance and carcass characteristics of steers fed diets with increasing dietary RDP concentrations supplied as urea. Steers (429 animals; BW = 423 ± 4.5 kg) were sorted into 3 blocks according to BW and assigned to 1 of 6 treatments (6 pens per treatment) in a randomized complete block design. Treatments were a 2 × 3 factorial arrangement of either no ZH or ZH (75 mg ZH per steer daily) supplemented to finishing diets containing 0, 0.5, or 1.0% urea of dietary DM. Pen weights were recorded before treatment initiation; urea was fed for 27 d, and ZH treatments were fed for 24 d with a 3-d withdrawal period. Pen weights were recorded before transporting steers to a commercial abattoir. Continuous response variables were analyzed using the MIXED procedure and categorical data were analyzed using the GLIMMIX procedure of SAS. No ZH × dietary urea interactions ( ≥ 0.14) occurred for all performance and carcass response variables. Feeding ZH for the last 27 d (included a 3-d withdrawal period) of the finishing period increased ( < 0.01) ADG, decreased ( < 0.01) DMI, and increased ( < 0.01) G:F compared with no ZH. In addition, ZH increased HCW ( < 0.01), dressing percentage ( < 0.01), LM area ( < 0.01), and decreased ( = 0.01) yield grade. Increasing dietary urea linearly decreased ( = 0.01) ADG and DMI. A tendency for a linear decrease ( = 0.10) in HCW, and a tendency for a quadratic increase ( = 0.07) in marbling score were observed as urea increased in the diet. Results indicate that cattle supplemented with ZH do not require additional RDP in the diet, and that performance and carcass characteristics were negatively affected when urea was increased in the diet.