A randomized field study comparing differences in core body temperature, health, and performance in crossbred beef heifers administered 2 antimicrobial products given upon arrival at a stocker facility 1 1Contribution 16-223-J from the Kansas Agricultural Experiment Station, Manhattan. There was no external source of funding for this research

Effect of supplemental methionine on health and performance of receiving beef heifers

Methionine supplementation can improve immune function in transition dairy cattle. Our objective was to determine if supplemental methionine could improve health and performance of newly received growing cattle. Crossbred heifers (n = 384; 222 kg initial body weight; southeastern U.S. origin) were received in four truckloads (blocks) over 9 d. Heifers were weighed at arrival. The following day (d 0) cattle were vaccinated for viral and clostridial diseases, received 2.5 mg tulathromycin/kg body weight, and were stratified within the blocks by arrival body weight to 1 of 8 pens containing 12 heifers each. Within blocks, pens were assigned to 1 of 2 treatments: 0 (control) or 0.1725% Smartamine M to provide 0.1035% metabolizable methionine to the diet. Cattle were limit-fed at 2.2% of body weight daily (dry matter basis) on a diet containing 40% wet corn gluten feed, 34.5% dry-rolled corn, 10% corn silage, 7.5% supplement, 4% alfalfa hay, and 4% prairie hay. Pen weights were measured weekly to determine the feed offered the following week. Individual body weight and tail-vein blood samples were collected on d 0, 14, and 45. Plasma haptoglobin was measured to assess acute-phase protein response. Incidences of morbidity (1.6% for control, 2.6% for Smartamine M) and mortality (0.5% for both control and Smartamine M) were low. Between d 0 and 45, no differences were observed for average daily gain (1.24 vs. 1.27 kg/d; control vs. Smartamine M, P = 0.55) or gain:feed (0.107 vs. 0.110, P = 0.28), although dry matter intake was 1.3% greater (P < 0.01) for control than Smartamine M due to differences in diet dry matter concentration. An interaction between treatment and linear effect of day was detected for plasma haptoglobin (P < 0.05); over time, haptoglobin increased more for control (2.15, 2.28, and 2.95 mg/mL at 0, 14, and 45 d) than for Smartamine M (2.35, 2.37, and 2.58 mg/mL). Supplemental methionine may alleviate acute-phase protein responses in stressed receiving cattle.

A systematic review and network meta-analysis of injectable antibiotic options for the control of bovine respiratory disease in the first 45 days post arrival at the feedlot

We conducted a systematic review and network meta-analysis to determine the comparative efficacy of antibiotics used to control bovine respiratory disease (BRD) in beef cattle on feedlots. The information sources for the review were: MEDLINE®, MEDLINE In-Process and MEDLINE® Daily, AGRICOLA, Epub Ahead of Print, Cambridge Agricultural and Biological Index, Science Citation Index, Conference Proceedings Citation Index - Science, the Proceedings of the American Association of Bovine Practitioners, World Buiatrics Conference, and the United States Food and Drug Administration Freedom of Information New Animal Drug Applications summaries. The eligible population was weaned beef cattle raised in intensive systems. The interventions of interest were injectable antibiotics used at the time the cattle arrived at the feedlot. The outcome of interest was the diagnosis of BRD within 45 days of arrival at the feedlot. The network meta-analysis included data from 46 studies and 167 study arms identified in the review. The results suggest that macrolides are the most effective antibiotics for the reduction of BRD incidence. Injectable oxytetracycline effectively controlled BRD compared with no antibiotics; however, it was less effective than macrolide treatment. Because oxytetracycline is already commonly used to prevent, control, and treat BRD in groups of feedlot cattle, the use of injectable oxytetracycline for BRD control might have advantages from an antibiotic stewardship perspective.