title: Decreasing the frequency of energy supplementation from daily to three times weekly impairs growth and humoral immune response of preconditioning beef steers.
abstract: We evaluated the effects of frequency of energy supplementation on growth and measurements of innate and humoral immune responses of preconditioning beef steers following vaccination. Angus steers ( = 24; 221 ± 6.3 kg; 177 ± 4 d of age) were weaned on d -7 and kept in a single drylot pen with free access to tall fescue hay and concentrate DMI at 0.5% of BW (50:50 mix of soyhulls and corn gluten pellets; DM basis) from d -7 to 0. On d 0, steers were stratified by BW and age and randomly assigned to 1 of 8 feedlot pens (3 steers/pen). Treatments were randomly assigned to pens (4 pens/treatment) and consisted of steers provided daily free access to ground tall fescue hay and similar weekly concentrate DMI (1% of BW times 7 d), which was divided and offered either daily (S7) or 3 times weekly (S3; Monday, Wednesday, and Friday) from d 0 to 42. Individual BW was measured before feeding on d 0 and 42, after 12 h of feed and water withdrawal. Steers were vaccinated against infectious bovine rhinotracheitis, bovine viral diarrhea virus (BVDV), and clostridium on d 7 and 21. Blood samples were collected from the jugular vein on d -7 and 4 h after concentrate supplementation on d 0, 7, 8, 9, 10, 14, 21, 22, 23, 24, 28, 35, and 42. Steers offered concentrate daily had greater ( ≤ 0.02) BW on d 42, overall ADG, and total DMI, but similar ( = 0.14) G:F, than S3 steers. On days that S7 and S3 steers were offered concentrate, total DMI was greater and hay DMI was less for S3 vs. S7 steers ( ≤ 0.05). On days that only S7 steers were supplemented, hay DMI was greater, but total DMI was less for S3 vs. S7 steers ( ≤ 0.05). Mean CP and NEg intake were greater ( ≤ 0.03) for S7 vs. S3 steers. Plasma cortisol concentrations on d 7 and 28, and mean plasma haptoglobin concentrations, but not liver mRNA expression of haptoglobin ( = 0.75), were greater for S3 vs. S7 steers ( ≤ 0.03). Plasma IGF-1 concentrations on d 0 and urea nitrogen on d 1 and 3, relative to vaccination, were greater for S7 vs. S3 steers ( ≤ 0.008). Positive seroconversion to BVDV-1b on d 42 and mean serum BVDV-1b titers were greater for S7 vs. S3 steers ( ≤ 0.05). In summary, decreasing the frequency of concentrate supplementation from daily to three times weekly, during a 42-d preconditioning period, decreased growth performance, increased plasma concentrations of haptoglobin and cortisol, and decreased vaccine-induced antibody production against BVDV-1b of beef steers.
authors.forename: L F A
authors.initials: LF
authors.lastname: Artioli
authors.forename: P
authors.initials: P
authors.lastname: Moriel
authors.forename: M H
authors.initials: MH
authors.lastname: Poore
authors.forename: R S
authors.initials: RS
authors.lastname: Marques
authors.forename: R F
authors.initials: RF
authors.lastname: Cooke
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001806:Blood Urea Nitrogen; D002417:Cattle / Q000502:physiology*; D002418:Cattle Diseases / Q000097:blood / Q000517:prevention & control; D004032:Diet / Q000662:veterinary*; D019587:Dietary Supplements; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014612:Vaccines / Q000276:immunology; D003313:Zea mays / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D014612:Vaccines; D007334:Insulin-Like Growth Factor I