Effects of Saccharomyces cerevisiae subspecies boulardii CNCM I-1079 on feed intake by healthy beef cattle treated with florfenicol and on health and performance of newly received beef heifers

¹ Texas Tech University Lubbock 79409
² West Texas A&M University, Canyon 79016
³ Texas A&M Research and Extension Center, Amarillo 79106; West Texas A&M University, Canyon 79016

^* To whom correspondence should be addressed. E-mail: michael.galyean{at}ttu.edu.

	Abstract

Effects of a live yeast supplement (Saccharomyces cerevisiae subspecies boulardii CNCM I-1079; ProTernative Stress Formula [PTSF] yeast) on DMI, performance, and health of beef cattle were evaluated in 3 experiments. In Exp. 1, a pilot study was conducted with 10 healthy beef steers fed a 65% concentrate diet to evaluate effects of florfenicol (s.c. in the neck vs. sterile water injection) on DMI. Steers injected with florfenicol had 15.6 (P = 0.092) and 22.2% (P = 0.015) decreases in DMI compared with controls on the day of and day after injection, respectively, with no differences for the remainder of the 7-d period. In the main study of Exp. 1, healthy beef steers (6 pens of 5 steers each/treatment) were fed the Control or PTSF yeast diets (0.5 g of yeast·steer^-1·d^-1) for 5 d before being injected s.c. with florfenicol. Compared with the 5 d before injection, DMI decreased after injection, but it did not differ (P > 0.66) between treatments on the day of and day after injection. By the second day after injection, DMI tended (P = 0.107) to increase for steers fed PTSF yeast vs. Control steers, with a similar pattern from on the third day after injection (P = 0.197). No differences were noted between treatments for the remainder of the 7-d period or for the subsequent 2 wk. In Exp. 2, 3 separate loads of beef heifers (277 heifers; average initial BW = 230.3 kg) were shipped from auction barns and assigned randomly to 1 of 2 treatments (5 pens/treatment) during 35-d receiving periods: 1) Control = 65% concentrate receiving diet; or 2) PTSF yeast = 65% concentrate receiving diet with PTSF yeast added to supply 0.5 g of yeast/(heifer·d). All heifers were treated with florfenicol on arrival, and PTSF yeast heifers received approximately 1 g of yeast via an oral paste at the time of processing. Averaged over the 3 loads, treatments did not affect (P > 0.12) DMI, ADG, or G:F during the 35-d period, but the percentage of cattle treated once or more for respiratory disease (BRD) was greater for Control (P = 0.04) than for PTSF yeast heifers (24.0 vs. 13.78% respectively). In Exp. 3, 2 separate loads of beef heifers (180 heifers; average initial BW = 209.0 kg) that were not treated with antibiotic at the time of arrival processing were fed a 70% concentrate receiving diet and assigned the same 2 treatments as in Exp. 2. No differences (P > 0.72) were noted between treatments in ADG, DMI, and G:F for the 35-d receiving period, and BRD morbidity pooled across loads did not differ between treatments (40.2 vs. 33.1% for Control vs. PTSF yeast). Providing PTSF yeast in an oral paste at the time of processing combined with the addition of 0.5 g/(animal·d) in the diet had little effect on receiving period performance; however, it decreased BRD morbidity in heifers given florfenicol on arrival but was without effect on BRD morbidity in heifers that did not receive a prophylactic antibiotic.

Key Words: bovine respiratory disease, dry matter intake, feedlot beef cattle, florfenicol, Saccharomyces cerevisiae subspecies boulardii