Physiological traits that are biologically associated with feed efficiency may be useful indicator traits residual feed intake (RFI). The objective of this study was to examine the relationships between RFI, temperament, serum hormones and serum metabolites in growing heifers. A 4 yr study (n = 114-119 heifers/yr) was conducted with Brangus heifers (Initial BW = 271 ± 26 kg) that were weaned for 25.5 ± 8.6 d prior to high roughage diet adaptation (ME = 2.0 Mcal/kg DM). Individual dry matter intakes (DMI) were measured using Calan gate feeders and BW measured at 7-d intervals during the 70-d studies. RFI was calculated as the residual from the linear regression of DMI on mid-test BW0.75 and average daily gain (ADG). Temperament scores and exit velocity (EV) were taken at 0-d. Temperament index (TI) was calculated as the average of EV and chute score. On 0-d, blood samples were collected and assayed for partial blood counts (WBC, RBC, hemoglobin, HB), metabolites (total protein, TP; glucose; creatinine; blood urea nitrogen, BUN; β-hydroxybutyrate, BHB) and hormones (cortisol; insulin-like growth hormone I, IGF-I). Across all heifers, RFI was positively correlated with DMI (0.70) and feed:gain (0.59). Heifers with low RFI (< 0.5 SD from mean RFI 0.00 ± 0.71 kg/d) consumed 16 percent less DMI and had 16 percent lower feed:gain than heifers with high RFI (> 0.50 SD from mean RFI). RFI was weakly correlated (P < 0.05) with WBC (0.15), HB (-0.11), total protein (-0.10), BUN (0.10), creatinine (-0.11) and BHB (0.13). Hemoglobin and BHB were weakly correlated with all feed efficiency traits except feed conversion ratio (FCR). No phenotypic correlation was found between cortisol and IGF-I with RFI. Temperament was not correlated with RFI. Cortisol, creatinine and glucose were moderately correlated with all temperament traits. Low TI heifers (calm) had significantly higher Final BW, ADG and DMI than high TI heifers. Calm animals had significantly lower cortisol, HB, creatinine and glucose and higher BHB. These results suggest that the temperament and serum metabolites evaluated in this study have limited utility as indicator traits for RFI in growing heifers.

The objective of this trial was to evaluate the effect of a multi-strain probiotic on serum concentrations of selected metabolites in young calves. Holstein heifers (n = 112) from a commercial dairy were enrolled within 48 h of birth and placed into individual hutches. Calves were weaned at 60 d of age and remained in their hutches until 90 d of age, when they were moved to group housing. Calves were placed into 2 treatment groups: 1) control and 2) B. subtilis, B. lichenformis, L. animalis, and P. freudenreichii probiotic (Bovamine Dairy Plus, Chr. Hansen, Milwaukee, WI). Control calves received 0.5 g of lactose in milk once daily until weaning and 0.75 g in grain thereafter. Treatment calves received 0.5 g (1.1 × 10^10 cfu/g) probiotic in milk once daily until weaning and 0.75 g (1.65 × 1010 cfu/g) probiotic in grain thereafter. Jugular blood samples (6 mL) were collected at 14, 25, 45, 63, 77, 120, and 180 d of age for the determination of serum β hydroxy-butyrate (BHB), plasma glucose, non-esterified fatty acid (NEFA), total free amino acids (TFAA), blood urea nitrogen (BUN), and tumor necrosis factor-α (TNF). Data were analyzed as a mixed linear model to determine the fixed effects of treatment, day, and their interaction and also the random effect of calf. Single degree of freedom contrasts were used to evaluate the effect of phase (pre- vs. post-weaning) and the interaction of treatment with phase. Concentrations of BHB increased throughout the 180 d of the study and were greater (P < 0.001) in the post-weaning (661 μM) vs. pre- weaning (240 μM) phase and greater for the probiotic-treated calves in the post-weaning phase only (treatment × phase, P < 0.001). Glucose concentrations were greater (P < 0.001) for the pre-weaning (88.0 mg/dL) vs. post-weaning (81.1 mg/dL) phase and greater for calves receiving probiotics in the pre-weaning phase only (Treatment × phase, P < 0.01). Non- esterified fatty acid (NEFA) concentrations were greater (P < 0.001) in the pre-weaning vs. post-weaning phase and were greater in calves not receiving probiotics (treatment × phase, P = 0.0036).Serum TFAA concentrations were greater (P < 0.001) in the pre-weaning (3.37 mM) vs. post-weaning (3.03 mM) phase and greater for probiotic-treated vs. control calves (3.22 mM vs. 3.11 mM; P < 0.001). Concentrations of BUN were greater (P ≤ 0.001) in the post-weaning vs. preweaning phase and were higher for probiotic treated calves vs. control in the post-weaning phase (P < 0.001). Tumor necrosis factor-α (TNF) concentrations were affected by treatment (P< .001). Calves that received probiotic supplementation had lower TNF concentrations on day 63 of life when compared to control calves on day 63 of life. Data suggest that nutrient metabolism and ruminal development were enhanced by feeding a multi-strain probiotic.

MSCAGR (Animal Science) / Department of Animal Science / The study evaluated the nutritive value of orange pulp- buffalo grass (OPBG) silage as a po-tential pig feed. In experiment 1, OPBG was ensiled in 58 one-litre jars, split into Reno-zyme® enzymes (containing α-amylases and β-endo 1, 3; 1, 4 beta glucanase) (denoted OPBGE) and 18 without enzyme (denoted OPBG). Samples were collected from the lab on days 7, 15 and 30 in a three by two factorial design (period by treatment). In Experiment 2, 12 South African Windsnyer-type (SAWIP) (27.2±3.9 kg) and 12 Large White- Landrace crosses (LW x LR) (28±9.8 kg) were fed diets containing different levels of bulk-ensiled OPBG ad libitum for 30 days, in a 2 X 3 (breed by level of OPBG (control, low (15% OPBG) and high (30% OPBG))) factorial arrangement. The apparent total tract digestibility (ATTD) of the pigs was measured during week 3 of feeding. The average body gain ABG average daily feed intake (ADFI), average daily gain (ADG), average gain to feed ratio (AG: F) were measured weekly. Serum glucose (GLU) , blood urea nitrogen (BUN), creatinine (CREAT), cholesterol, (CHOL) and triglycerides (TG) were measured during week 4 of the experiment. The levels of CP, EE, NDF, water soluble carbohydrates (WSC), lactic acid (LA) and pH were different (P<0.05) for OPBGE and OPBG on day 7. However the OPBGE concentra-tions of DM, ASH, CP, NDF, HEMI, WSC, LA and pH were higher (P<0.05) compared to OPBG. The OPBGE was lower (P<0.05) on EE and ADF, compared to OPBG on day 7. The levels of DM, ASH, CP, NDF, ADF, HEMI, LA and WSC were different (P<0.05) for OPBGE and OPBG on day 30. However the OPBGE levels of DM, CP, NDF, ADF, LA and WSC were higher (P<0.05) compared to OPBG. ASH, EE and HEMI were lower (P<0.05) on day 30. There were significant diets x day interactions (P<0.05) for DM, ASH, CP, EE, NDF, ADF, HEMI, WSC, and LA, but not for pH. The aerobic stability study was inconclusive. The digestibility levels of OM and NDF were different (P<0.05) for LW x LR and SAWIP, where LW x LR ATTD on OM and NDF was higher (P<0.05) compared to SAWIP for all diets. The LW x LR ADG was higher (P<0.05) compared to SAWIP for all diets. There was a diet x breed interaction effect (P <0.05) on ADG whereby the BUN and CREAT were different (P <0.05) for LW x LR and SAWIP. The SAWIP BUN was higher (P<0.05), but the CREAT and TG were lower (P<0.05) compared to LW x LR for all diets fed. In conclusion, OPBG inclu-sion in pig feed enhanced the quality of feed, digestibility, performance and blood metabo-lites profile. / NRF