Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 1/10/2011
Publication Date: 2/6/2011
Citation: Runyan, C.A., Herring, A.D., Ridpath, J.F., Cabaniss, M.S., Muntean, C.T., Sawyer, J.E. 2011. Feed intake and weight gain in beef steers of known genetic background following BVDV challenge [abstract]. American Society for Animal Science, Southern Section Meeting, February 6-9, 2011, Orlando, Florida. p. 2. Interpretive Summary:
Technical Abstract: Angus-sired steers (n = 95) born in the spring of 2008 produced from TAMU McGregor Genomics Project cows were evaluated for individual feed intake and ADG for 42 d following challenge to BVD virus. Steers were not vaccinated for BRD prior to trial initiation, and were verified to be BVD-free. Prior to BVDV challenge, steers were assigned to BRD vaccination treatments (VACTRT) of killed (KV; n = 29), modified-live (BLV; n = 34) or non-vaccinated (NON; n = 31) with sires and genomics cow families stratified across VACTRT. On d-56, KV steers were administered their first injection; on d-35, KV steers were administered a booster injection and MLV steers were administered their only injection. On d 0, all steers were given an intranasal challenge with BVDV strain CA0401186a (Type 1b) from the National Animal Disease Center. Cattle were weighed on d 0, 14, 28, and 42 following challenge. Rectal temperature (RT) was used to evaluate health status; steers over 40.0 deg C were treated with an antimicrobial. Cattle were fed by hand daily in 4 pens equipped with GrowSafe feed bunks. Daily feed intake (DFI) was analyzed (as fed) through mixed model repeated measures with a model that included VACTRT, day, VACTRT x day, pen, maternal grandsire (MGS) and VACTRT x MGS. Large differences were observed in DFI due to VACTRT, day, and VACTRT x day. MLV steers consumed approximately 0.5 kg more than KV and NON steers. The most substantial differences in DFI across VACTRT appeared to occur from d 7 to 10 following challenge with NON steers consuming 0.8 to 3.1 kg less than vaccinated steers. Differences in DFI were also seen due to MGS with a difference of 1.4 kg across MGS means (11.4 +/= 0.14 to 12.8 +/= 0.14, as fed) and VACTRT x MGS with a range of 0.4 to 1.0 kg across VACTRT within MGS groups. DFI was also compared between steers with > 40.0 deg C RT within 14 d following challenge and those less than or equal to 40.0 deg C; steers > 40 deg C RT consumed 0.4 to 3.9 kg less DFI during d 7 to 10. ADG was evaluated for the 3 14-d periods due to VACTRT, pen, MGS, VATRT x MGS and d-0 weight as a covariate, but no differences existed due to VACTRT or MGS in any period.