Journal of animal science最新文献

Thirty mature Quarter Horse geldings were used in a completely randomized 32-d study to test the hypotheses that supplemental live Saccharomyces cerevisiae CNCM I-1077 improves apparent digestion, stabilizes the fecal pH, reduces gut permeability, maintains microbial communities, and decreases inflammation in horses fed a high-starch diet. Horses were stratified by body weight, age, and body condition score (BCS) to one of two treatments: concentrate formulated with 2g starch • kg BW-1 • meal-1 (CON; n=15) or the same concentrate top-dressed with 25g/d Saccharomyces cerevisiae CNCM I-1077 (SC; n=15; 8×108 CFU). Horses were fed individually in stalls every 12h. Between meals, horses were housed in dry lots with ad libitum access to water and Coastal bermudagrass hay. On d0 and 32, BW and BCS were recorded, and blood was collected before feeding and 2, 8, 16, and 24 h postmeal on d32 to analyze serum D-lactate. Fecal samples were collected on d0, 16, and 32 at 8, 16, and 24h post-meal for fecal pH and starch content. Intake and fecal production were recorded over 4-d to measure digestibility on d28-31. Whole blood total bacterial counts and 16S fecal microbiota rRNA sequencing were performed at d0, 16, and 32. Results revealed an increased ∆BW in SC horses compared with CON horses (P=0.03), with no change in BCS (P=0.97). D-lactate tended to be greater in SC horses on d32 at 16 and 24h post-meal compared with CON horses (P=0.10). Concentrations of TNFα and LogCCL2 decreased from d0 to d 32 regardless of dietary supplementation (P≤0.02). Fold change of percent reads from d0 in whole blood bacterial 16S rRNA did not differ between groups. Fecal starch was undetectable, and there were no differences in intake or apparent digestibility. Fecal pH tended (P=0.07) to be lower in CON at 0h on d32 (6.03 ± 0.06) than d16 (6.14 ± 0.06). Additionally, pH tended (P=0.09) to be lower in CON (6.03 ± 0.06) than SC (6.16 ± 0.06) at 0h on d32. Supplementation of Saccharomyces cerevisiae CNCM I-1077 maintained Bacteroidales and reduced acidosis-like bacteria like Streptococcus and potential pathogens like Enterobacteriaceae, Stenotrophomonas, and Rhodococcus at d16 (P<0.05). Further, supplementation increased fibrolytic bacteria at d32, such as Ruminococcus, Fibrobacter, and Succinivibrio (P<0.05). These results indicate Saccharomyces cerevisiae CNCM I-1077 increases BW and promotes a more diverse microbiome when hoses are fed ad libitum hay and a high-starch concentrate.

The number of beef × dairy animals entering feedlots has increased, but the response of beef × dairy cattle to growth-promoting implants has not been well characterized. The objective of this study was to evaluate the effects of breed type and implant administration on live performance, carcass characteristics, sera metabolites, and immunohistochemical (IHC) outcomes. Forty-eight steers (average body weight [BW] = 417±22 kg) were sorted by breed into groups of predominantly Angus (B), black-hided beef × primarily Holstein (B×D), or Holstein (D), and half of the steers within each breed type were administered a steroidal implant. Data were analyzed as a 3×2 factorial, including repeated measures for sera metabolite and IHC outcomes. Main effects were breed (B, B×D, or D) and implant status (no implant [CON] or Revalor-XS [200 mg trenbolone acetate + 40 mg estradiol-17β] on d 0 [IMP]). Interaction of main effects to determine breed-specific responses to implants were also evaluated. Steers were fed to a target final shrunk BW of 658 kg within breed type. Blood, longissimus thoracis biopsies, and BW were collected on d 0, 28, 70, 98, and 126; BW was also collected prior to harvest. Implanted steers had greater average daily gain (ADG), interim BW, and final BW (P ≤ 0.04). Overall ADG tended to be greatest (P = 0.07) in B×D steers. The IMP treatment, and B×D and D steers had increased (P < 0.01) mean sera concentrations of non-esterified fatty acids and insulin-like growth factor-I (IGF-I), compared to CON and B steers. The IMP carcasses had greater hot carcass weight (HCW), dressing percentage, and REA (P ≤ 0.03) and decreased KPH (P < 0.01). By analyzation of IHC, myosin heavy chain (MHC) Type I fibers were the largest and most abundant in D (P ≤ 0.03). Increased abundance of estrogen receptors and greatest G protein-coupled receptor-1 score was observed for D, while B×D were intermediate, and B had the fewest estrogenic receptors (P ≤ 0.02). Regardless of breed type, IMP steers had increased estradiol-17β and trenbolone-17β concentrations (P < 0.01) with no effect on MHC fiber type and minimal effects on satellite cell outcomes. These results indicated B×D and IMP treatments increased muscling and decreased internal fat deposition compared to D and CON, respectively. Dairy-influenced breed types exhibited increased estrogenic receptor abundance. Additionally, few breed × implant interactions suggest B, B×D, and D steers responded similarly to growth-promoting implants.

This study aimed to quantify the effects of physiological status (PS) and the potential interaction of this factor with days of pregnancy (DOP) on beef heifers' weight variation, intake, and digestion kinetics. Twelve rumen-cannulated zebu beef heifers (n = 7 pregnant; n = 5 nonpregnant) were used. Heifers were placed in individual pens and fed medium-quality corn silage plus a protein-based supplement. Heifers' body weight was assessed at the beginning and end of each collection period. The feed intake was measured daily. Target outcomes were evaluated at 107, 170, 208, 240, 267, and 286 DOP. The apparent total-tract digestibility was determined considering the fecal spot collection, during 5 d within each collection period. Omasal and ruminal digesta samples were collected at 107, 208, and 267 DOP for determination of partial digestibilities and diet component outflow. For these purposes, Co-EDTA and indigestible neutral detergent fiber (iNDF) were used as indicators. All data were analyzed using a mixed model framework, considering the PS and DOP as fixed effects and the animal as a random effect. Significant differences were declared when P ≤ 0.05. Pregnant heifers showed an increase in body reserves (+35 kg) from 107 to 240 DOP, but experienced a decrease in shrunk body weight (-36 kg) from 240 to 286 DOP. The intake of dry matter (DM), organic matter (OM), crude protein (CP), and ash- and protein-free neutral detergent fiber (apNDF) increased as pregnancy progressed (P < 0.04). The apparent total-tract digestibility of DM tended to be lower (P = 0.09), and the apparent total-tract digestibility of apNDF was reduced (P < 0.01) in pregnant heifers. The digestibility of CP was higher (P < 0.01) on days 267 and 286 in pregnant cows compared to nonpregnant heifers. The ruminal digestibility of OM tended to be lower (P = 0.09) in pregnant beef heifers, while the ruminal digestibility of apNDF was lower (P = 0.02) in pregnant heifers compared to nonpregnant ones. The ruminal pool of wet matter and DM was lower (P ≤ 0.01) in pregnant heifers at 267 DOP. In all periods, the outflow tended to be greater (P = 0.06) in pregnant heifers compared to nonpregnant heifers. Pregnant beef heifers exhibited a faster (P = 0.01) digesta passage rate during late gestation. In conclusion, late-gestating beef heifers are less efficient in extracting energy from feed compared to nonpregnant animals.

The objective was to evaluate growth performance and carcass traits of finishing beef heifers sourced and finished in different regions in the U.S. Heifers (n = 190; initial body weight [BW] 483 ± 0.4 kg and 425 ± 1.9 kg for South Dakota [SD] and TX sourced, respectively) were used in a 2 × 2 factorial arrangement of origin state (SD vs. TX) and finishing state (SD vs. TX) was used. Heifers were allotted on day -1 to: 1) sourced from SD and finished in SD (SD-SD), 2) sourced from SD and finished in TX (SD-TX), 3) sourced from TX and finished in SD (TX-SD), and 4) sourced from TX and finished in TX (TX-TX). Heifers were weighed on d -1, 3, 15, 28, 56, 78 (TX-TX and SD-TX) and 90 (SD-SD and TX-SD). On day 0, SD-TX and TX-SD heifers were shipped to their respective finishing locations. The following morning (day 1), SD-TX and TX-SD heifers were individually weighed to determine transit shrink. To monitor transit stress effects, vaginal temperature probes were used on all SD-TX and TX-SD heifers and a portion of SD-SD and TX-TX heifers on day -1 and removed on day 3. Clinical attitude scores (CAS) were recorded on days -1, 0, 1, 2, and 3 for bovine respiratory disease symptoms. Transported heifers had decreased temperatures (P ≤ 0.01) during transit and post-transit and increased (P ≤ 0.01) vaginal temperature during loading and unloading compared to non-transported heifers. On days 0, 1, and 3 there was a shift in the distribution of heifers that had a CAS score greater than 0 for TX-TX, SD-TX, and TX-SD. Heifers endured elevated ambient temperatures (temperature-humidity index > 75) for 54% and 18% of the feeding period for TX and SD. Growth performance and carcass trait interactions were significant (P < 0.01) except for day -1 BW, percent shrink during transit, average daily gain, dressing percent, ribeye area, and liver abscess severity, which did not differ (P > 0.30). A shift in the distribution (P < 0.02) towards a greater proportion of Yield Grade (YG) 1 and Select carcasses was observed for TX versus SD. Overall, heifers transported to higher ambient temperatures had improved overall YGs but decreased dry matter intake, quality grades (QG), and limited growth recovery (45 kg lighter) following transit than non-transported heifers. Heifers transported to lower ambient temperatures recovered growth and had improved QG (P < 0.02) at the same thickness of rib fat compared to non-transported heifers but had decreased overall yield and yield grades.