Effects of graded levels of vitamin E on inflammatory response and evaluation of methods of supplementing vitamin E on performance and health of beef steers1

Professional Animal Scientist, Apr 2003 by Rivera, J D, Duff, G C, Galyean, M L, Hallford, D M, Ross, T T

Abstract

Two experiments were conducted evaluating dietary level of vitamin E and methods of delivering vitamin E to beef cattle. In Exp. 1, 16 beef steers were used to examine effects of 0, 285, 570, or 1,140 IU of vitamin E/d per animal on performance, febrile response, and metabolic responses following intranasal exposure to infectious bovine rhinotracheitis virus (IBRV). In Exp. 2, 120 steer calves were used to evaluate efficacy of three methods of delivering vitamin E on performance and health during a 28-d receiving period. Treatments were an oral drench of vitamin E, a subcutaneous injection of vitamin E, or supplemental vitamin E added to the 70% concentrate diet. No effects (P>0.10) of vitamin E concentration on ADG, BW, DMI, or serum metabolites were observed in Exp. 1. A linear increase (P

(Key Words: Vitamin E, Beef Cattle, Health.)

Introduction

Defenses against microbial invasion include physical barriers, focused responses (inflammatory response), and specific immunity (antibody production; Tizard, 1996). Supplementing vitamin E at greater than recommended levels has improved health in feedlot cattle (Secrist et al., 1997). Rivera et al. (2002) reported an increase in circulating antibodies to ovalbumin after cattle had been supplemented with 1,140 IU of vitamin E/d for 21 d. Similarly, Nemec et al. (1990) noted an increase in antibody production to S. tyrphimurium when vitamin E was supplemented at 1,400 IU daily. Data are lacking, however, with regard to effects of vitamin E on the inflammatory immune response. The results of Rivera et al. (2002) demonstrated that one difficulty with feeding vitamin E to newly received stressed cattle is variability in DMI during the first part of the receiving period. Thus, intakes of supplemental vitamin E when delivered in the feed can fall short of targeted levels when DMI is low. Decreased intake of vitamin E might help explain why differences regarding effects of vitamin E on morbidity or lack of differences in morbidity have been noted by various researchers. The potential exists to evaluate other methods of delivering vitamin E to newly received cattle. Hays et al. (1987) and Galyean et al. (1991) determined that an i.m. injection of vitamin E was not as effective as feeding the vitamin; however, data on health of feedlot cattle are lacking when the vitamin E has been delivered by s.c. injection or by oral drenching of the vitamin.

Objectives of these experiments were 1) to evaluate the effects of vitamin E concentrations on the inflammatory response of beef cattle and 2) to evaluate three methods of vitamin E delivery on health and performance of feedlot cattle.

Materials and Methods

The New Mexico State University Institutional Animal Care and Use Committee approved all experimental protocols. In Exp. 1, 20 crossbred (Bos taurus x Bos indicus) beef steers (initial average BW = 245 kg) were purchased from a local livestock auction in Clayton, NM and transported to the Clayton Livestock Research Center (CLRC). After arrival at the CLRC, cattle were administered a modified live infectious bovine rhinotracheitis/parainfluenza-3 virus/bovine viral diarrhea/bovine respiratory syncytial virus (IBR-PI^sub 3^-BVD-BRSV) plus Pasteurella haemolytica vaccine (Pyramid 4 + Presponse(R); Ft. Dodge Animal Health, Ft. Dodge, IA) and a seven-way clostridial vaccination (Ultrabac-7 (R); Pfizer Animal Health, Exton, PA). In addition, the cattle were dewormed with moxidectin (Cydectin (R); Ft. Dodge Animal Health). Steers also were branded and given an individual ear tag, after which they were fed wheat hay top-dressed with a 70% concentrate diet (Table 1) with no added vitamin E. Steers were housed at the CLRC for a period of 20 d and then were shipped 700 km to the New Mexico State University Campus Farm in Las Cruces, NM. The 70% concentrate diet was prepared at the CLRC and was shipped to Las Cruces. After arrival, cattle were housed in a large soil-surfaced pen with access to shade and water. Steers initially were fed alfalfa hay for a period of 7 d followed by the 70% concentrate diet. At this time, steers began to be trained to consume feed from a Calan Gate Feeding System (American Calan, Northwood, NH). Four steers were removed from the study because of difficulties in adapting to the Calan Gates. The remaining 16 steers were weighed 7 d before initiation of the viral challenge, stratified by BW, and assigned to one of four treatments: 0, 285, 570, or 1,140 IU of vitamin E added as a top dress on the 70 % concentrate diet. Steers were fed once daily at 0800 h. Following the delivery of feed, vitamin E was top-dressed on the diet (Table 1). Feed bunks were evaluated twice daily to ensure that each animal had adequate access to feed; however, bunks were managed so that no feed was left at the time of the morning feeding. This feeding method ensured that each animal consumed its full allotment of vitamin E. Following the 7-d supplementation period, cattle were taken to the working facilities at approximately 0600 h, where BW was recorded on a 907-kg capacity LBS scale (LBS Inc., Garden City, KS) in 0.91-kg increments, and rectal temperatures were recorded. Additionally, an 8-mL blood sample was collected via jugular venipuncture into serum separator collection tubes (Corvac(R); Sherwood Medical Company, St. Louis, MO). Blood was allowed to clot for 30 min and then was centrifuged at 1,000 x g for 30 min. Serum was separated and stored frozen.

Following all sample collections, a 4-mL dose of infectious bovine rhinotracheitis virus (IBRV; Cooper Strain, Lot 97-11, titer value 10^sup 9.4^ tissue culture infective dose^sub 50^/2 mL; USDA, National Animal Disease Laboratory, Ames, IA) was administered to each steer. The IBRV was brought to a 4-mL volume with phosphate-buffered saline (Sigma P-3813; Sigma Chemical Company, St. Louis, MO), and 2 mL were injected into each nostril using a 5-mL disposable syringe. Following administration of IBRV, the cattle were returned to their pen where they received their respective vitamin E treatments for the remainder of the experiment. Rectal temperatures were recorded daily for 5 d and thereafter on d 7, 14, and 21 following administration of IBRV. To minimize effects of environment on core body temperature, all rectal temperature measurements were taken at 0630 h. Blood samples were collected on d 3, 5, 7, and 14, and BW was recorded on d 7, 14. and 21 as described previously. Feed bunks were cleaned on d 7, 14, and 21 to determine DMI for those 7-d periods. Daily grab samples of feed were taken at random before the morning feeding, composited, and analyzed for DM, ash, CP, and NDF (Goering and Van Soest, 1970). On d 15. one animal was still expressing symptoms of morbidity and was medicated with tilmicosin phosphate (Micotil(R); 10 mg/kg of BW; Elanco Animal Health, Indianapolis, IN).