To assess plasma trace mineral (TM) concentrations, the acute phase protein response, and behavior in response to a lipopolysaccharide (LPS) challenge, 96 Angus cross steers [average initial body weight (BW): 285 ± 14.4 kg] were sorted into two groups by BW (heavy and light; n = 48/group), fitted with an ear-tag based accelerometer (CowManager SensOor; Agis, Harmelen, Netherlands), and stagger started 14 d apart. Consecutive day BW were recorded to start the 24-d trial (d -1, 0). Dietary treatments began on d 0: common diet with either 30 (Zn30) or 100 (Zn100) mg supplemental Zn/kg DM (ZnSO4). On day 17 steers received one of the following injection treatments intravenously to complete the 2 × 3 factorial: 1) SALINE (~2-3 mL of physiological saline), 2) LOWLPS: 0.25 µg LPS/kg BW or 3) HIGHLPS: 0.375 µg LPS/kg BW. Blood, rectal temperature (RT), and BW were recorded on d 16 (-24 h relative to injection), and BW was used to assign injection treatment. Approximately 6, 24 (d 18), and 48 (d 19) h after treatment BW, RT, and blood were collected, and final BW recorded on d 24. Data were analyzed in Proc Mixed of SAS with fixed effects of diet, injection, diet × injection; for BW, RT, dry matter intake (DMI), plasma TM, and haptoglobin repeated measures analysis was used to evaluate effects over time. Area under the curve analysis determined by GraphPad Prism was used for analysis of accelerometer data. Body weight was unaffected by diet or injection (P ≥ 0.16), but there was an injection × time effect for DMI and RT (P < 0.05), where DMI decreased in both LPS treatments on d 16, but recovered by d 17, and RT was increased in LPS treatments 6 h post-injection. Steers receiving LPS spent less time highly active and eating than SALINE (P < 0.01). Steers in HIGHLPS spent lesser time ruminating, followed by LOWLPS and then SALINE (P < 0.001). An injection × time effect (P < 0.001) for plasma Zn showed decreased concentrations within 6 h of injection and remained decreased through 24 h before recovering by 48 h. A tendency for a diet × time effect (P = 0.06) on plasma Zn suggests plasma Zn repletion occurred at a greater rate in Zn100 compared to Zn30. These results suggest increased supplemental Zn may alter rate of recovery of Zn status from an acute inflammatory event. Additionally, ear-tag-based accelerometers used in this study were effective at detecting sickness behavior in feedlot steers, and rumination may be more sensitive than other variables.

To assess efficacy of bis-glycinate bound Zn, 36 crossbred wethers (34 ± 2 kg) were sorted by body weight into three groups and stagger started on a Zn deficient diet (18 mg Zn/kg dry matter; 22.5% neutral detergent fiber) for 45 d prior to a 15-d metabolism period (10 d adaptation, 5 d collection). On d 46, lambs were randomly assigned to dietary treatments (4 lambs treatment-1group -1): no supplemental Zn (CON) or 15 mg supplemental Zn/kg dry matter (ZINC) as Zn sulfate (ZS) or bis-glycinate (GLY; Plexomin Zn, Phytobiotics). Blood was collected from all lambs on d 1, 44, 56, and 61. Liver, jejunum, and longissimus dorsi samples were collected after euthanasia on d 61. Gene expression was determined via quantitative real-time polymerase chain reaction. Data were analyzed using ProcMixed of SAS (experimental unit = lamb; fixed effects = treatment, group, and breed) and contrast statements assessed the effects of supplemental Zn concentration (ZINC vs. CON) and source (GLY vs. ZS). After 15 d of Zn supplementation, plasma Zn concentrations were greater for ZINC vs. CON and GLY vs. ZS (P ≤ 0.01); tissue Zn concentrations were unaffected (P ≥ 0.27). Liver Cu concentrations were lesser for ZINC vs. CON (P = 0.03). Longissimus dorsi Mn concentrations were greater for ZINC vs. CON (P = 0.05) and tended to be lesser for GLY vs. ZS (P = 0.09). Digestibility of DM, OM, and NDF was lesser for ZINC vs. CON (P ≤ 0.05); ADF digestibility tended to be greater for GLY vs. ZS (P = 0.06). Nitrogen retention (g/d) tended to be greater for GLY vs. ZS (P = 0.10) and N apparent absorption was lesser for ZINC vs. CON (P = 0.02). Zinc intake, fecal output, retention, and apparent absorption were greater for ZINC vs. CON (P ≤ 0.01). Apparent absorption of Zn was -5.1, 12.8, and 15.0% for CON, ZS, and GLY, respectively. Nitrogen and Zn retention and apparent absorption were not correlated for CON (P ≥ 0.14) but were positively correlated for ZINC (retention P = 0.02, r = 0.52; apparent absorption P < 0.01, r = 0.73). Intestinal expression of Zn transporter ZIP4 was lesser for ZINC vs. CON (P = 0.02). Liver expression of metallothionein-1 (MT1) tended to be greater for GLY vs. ZS (P = 0.07). Although Zn apparent absorption did not differ between sources (P = 0.71), differences in post-absorptive metabolism may be responsible for greater plasma Zn concentrations and liver MT1 expression for GLY supplemented lambs, suggesting improved bioavailability of GLY relative to ZS.

The objective of this study was to evaluate growth performance, carcass characteristics, and plasma amino acid profiles of feedlot steers fed rumen-protected Lys. Forty-two Angus-cross steers (304 ± 25 kg) were blocked by weight and fed treatment diets for 180 d (growing d 0 to 55; finishing d 56 to 180): 1) Lys-deficient diet (CON; n = 12 steers), 2) Lys-adequate diet containing soybean meal (POS; n = 12 steers), or 3) Lys-deficient diet plus supplemental rumen-protected Lys (RPL; AjiPro-L; Ajinomoto Animal Nutrition North America, Eddyville, IA; n = 18 steers). Consecutive day bodyweights (BW) were recorded to begin and end growing and finishing. Individual steer dry matter intake (DMI) was recorded. Blood was collected on d 0, 56, and 179 for analysis of physiological free amino acids. Steers were harvested on d 180 and carcass characteristics were recorded. Data were analyzed using Proc Mixed of SAS 9.4. Steer was the experimental unit and treatment was the fixed effect for all parameters. Block was a fixed effect for growth performance, feed intake, and carcass data. The d 0 value for each parameter of physiological free amino acids was used as a covariate during analysis. The CON steers had greater BW, average daily gain (ADG), and gain to feed (G:F) at the end of growing (d 56; P ≤ 0.05) vs. POS and RPL. The CON steers also had greater final BW (P = 0.04) and overall ADG (P = 0.04) than RPL, while POS was intermediate. Carcass characteristics were not different across treatments [hot carcass weight, dressing percent, ribeye area, back fat, kidney/pelvic/heart (KPH) percent, marbling, or calculated yield grade; P ≥ 0.13]. Plasma urea N was greater in POS steers on d 56 and 179 (P ≤ 0.04). Plasma Lys and Arg concentrations were greater in POS at d 56 (P ≤ 0.02), however there was no difference among treatments for these two variables at d 179 (P ≥ 0.44). Steers in all treatments had greater DMI than predicted causing a negative metabolizable Lys balance for all treatments during growing. Though the metabolizable Lys balance was positive for POS and RPL-fed steers during finishing, the increased metabolizable Lys in these treatments may have decreased performance if other amino acids were imbalanced due to increased intakes.

The objective of these experiments was to assess the effects of food and water deprivation and transit duration on the behavior of beef feedlot steers. In Experiment 1, 36 Angus-cross steers (353 ± 10 kg) were stratified to six pens and assigned one of three treatments (n = 12 steers/treatment): control (CON; stayed in home pens with ad libitum access to feed and water), deprived (DEPR; stayed in home pens but deprived of feed and water for 18 h), or transported (TRANS; subjected to 18-h transit event and returned to home pens). In Experiment 2, 60 Angus-cross steers (398 ± 5 kg; 6 steers/pen) were transported either 8 (8H) or 18 (18H) h. Four 8H pens (n = 24 steers) and six 18H pens (n = 36 steers) were used for behavioral analysis. In both experiments, the time to eat, drink, and lay down was recorded for each steer upon return to home pens. Total pen displacements from the feed bunk were also assessed for the two hours following feed access in both experiments. Data were analyzed using Proc Mixed of SAS 9.4, with treatment as a fixed effect. Steer was the experimental unit for behavioral activities, while pen was the experimental unit for bunk displacements. Displacements were analyzed as repeated measures with the repeated variable of time. In Experiment 1, time to eat and drink was similar across treatments (P ≥ 0.17). However, TRANS laid down in 16.5 min while DEPR did not lay down until 70.5 min post-arrival to pen (P < 0.01). Deprived steers had greater bunk displacements in the first 70 min post-feed access than CON or TRANS, though displacements among treatments from 100 to 120 min post-feed access were similar (Treatment × Time: P = 0.02). In Experiment 2, both 8H and 18H steers laid down approximately 25 min post-home pen arrival (P = 0.14). There was no effect of transit duration or duration by time on bunk displacements (P ≥ 0.20), though displacements were greater from 0 to 20 min than from 20 to 30 min post-feed access (Time: P = 0.04). Steers that were deprived of feed and water were highly motivated to access those resources, while transported steers prioritized laying down. Producers should consider these priorities when preparing to receive cattle from a long transit event.

Fifty-four Angus-cross steers (297 kg ± 12) were stratified by body weight (BW) to pens (6 steers per pen) to determine effects of supplemental Zn on post-transit growth performance and blood and muscle metabolites. Dietary treatments started 25 d before trucking: control (CON; analyzed 54 mg Zn/kg DM), industry (IND; CON + 70 mg supplemental Zn/kg DM), and supranutritional Zn (SUPZN; CON + 120 mg supplemental Zn/kg DM). Supplemental Zn was bis-glycinate bound Zn (Plexomin Zn; Phytobiotics North America, Cary, NC). On d 0, steers were loaded onto a commercial trailer and transported 18 h (1,822 km). Individual BW were recorded on d -26, -25, -1, 0 (pre-transit), 1 (post-transit), 6, 27, and 28. Blood was collected on d -1, 1, 6, and 27. Longissimus thoracis biopsies were collected on d -1, 1, and 28. Daily individual feed disappearance was recorded via GrowSafe bunks. Data were analyzed using Proc Mixed of SAS with fixed effect of diet and steer as the experimental unit (growth performance, blood: n = 18 steers per treatment; muscle: n = 12 steers per treatment). Individual initial BW was used as a covariate in BW analysis. Contrast statements to test linear, quadratic, and Zn effects were used to analyze performance and blood parameters. Repeated measures analysis was used for post-transit DMI recovery and weekly post-transit DMI and Zn intake with the repeated effect of time. MetaboAnalyst 5.0 was utilized for statistical analysis of d 1 (off truck) muscle metabolites. Plasma Zn linearly increased due to Zn on d 1, 6, and 27 (P = 0.01), and off-truck (d 1) serum lactate increased over d -1 by 20, 0, and 20% in CON, IND, and SUPZN, respectively (Quadratic: P = 0.01). Muscle lactate tended to increase post-transit in CON and IND (P ≤ 0.07) but not SUPZN. Muscle metabolites relating to amino acid and nitrogen metabolism were increased in all treatments post-transit (P ≤ 0.02), and alanine-glucose cycle metabolites tended to increase in CON and IND (P ≤ 0.07). Steers supplemented with Zn recovered pre-transit DMI quicker than CON (by d 2: P = 0.01), while IND had greater overall post-transit DMI than CON with SUPZN intermediate (P = 0.04), and Zn-fed steers had greater ADG post-transit (P = 0.04). Zinc supplementation mitigated muscle or serum lactate increases due to transit and increased post-transit ADG.