title: Effects of feeding polyclonal antibody preparations on ruminal bacterial populations and ruminal pH of steers fed high-grain diets.
abstract: Three experiments with factorial arrangements of treatments were designed to test the efficacy of avian-derived polyclonal antibody preparations (PAP) against Streptococcus bovis (PAP-Sb) or Fusobacterium necrophorum (PAP-Fn) in reducing ruminal counts of target bacteria in beef steers supplemented or not with feed additives (300 mg of monensin/d and 90 mg of tylosin/d; MT). Feeding increasing doses of PAP-Sb in Exp. 1 or a single dose in Exp. 2 reduced S. bovis counts in a cubic fashion (P = 0.014). In Exp. 1 and 2, inclusion of MT in the diet had no effect (P > 0.05) on ruminal S. bovis counts. In Exp. 2, ruminal pH was increased (P < 0.05) by feeding PAP-Sb, MT, and PAP-Sb plus MT. Ruminal F. necrophorum counts were reduced by feeding PAP-Fn (P = 0.002) and MT (P < 0.001). Reduction in ruminal F. necrophorum counts was greater (P = 0.008) when feeding MT alone than when feeding PAP-Fn and MT together. In Exp. 3, ruminal S. bovis counts were not affected (P = 0.64) by PAP-Fn. Ruminal pH was not affected (P = 0.61) by feeding PAP-Fn, and the total anaerobic bacterial count was not affected (P > 0.05) by either PAP-Sb or PAP-Fn in Exp. 1 or Exp. 3. In conclusion, PAP of avian origin and against S. bovis or F. necrophorum were effective in reducing target ruminal bacterial populations. These PAP could be effective in preventing the deleterious effects associated with these bacteria, and possibly in enhancing animal performance.
authors.affiliation: Department of Animal Science, University of Minnesota, St. Paul 55108, USA.
authors.forename: N
authors.initials: N
authors.lastname: DiLorenzo
authors.forename: F
authors.initials: F
authors.lastname: Diez-Gonzalez
authors.forename: A
authors.initials: A
authors.lastname: DiCostanzo
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000907:Antibodies, Bacterial / Q000008:administration & dosage* / Q000276:immunology*; D002417:Cattle / Q000276:immunology* / Q000382:microbiology*; D004032:Diet / Q000662:veterinary*; D005675:Fusobacterium necrophorum / Q000187:drug effects / Q000276:immunology; D006863:Hydrogen-Ion Concentration; D007476:Ionophores / Q000494:pharmacology; D008297:Male; D008985:Monensin / Q000494:pharmacology; D012417:Rumen / Q000187:drug effects* / Q000276:immunology / Q000382:microbiology*; D016985:Streptococcus bovis / Q000187:drug effects / Q000276:immunology; D015645:Tylosin / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D000907:Antibodies, Bacterial; D007476:Ionophores; D008985:Monensin; D015645:Tylosin