The objective of this research was to determine the influence of implanting heavy wether lambs with 12 mg of zeranol (1 pellet Ralgro, Merck Animal Health. Madison, NJ, USA) 59 d before harvest. Average daily gain (ADG), feed efficiency, and carcass merit were evaluated. Polypay and crossbred wethers (n = 32) were equally divided into two treatment groups: non-implanted; (CON) or implanted with 12 mg of zeranol (IMP) in a randomized complete block design. Sixteen pens were used, resulting in eight replicate pens per treatment. Wethers were fed a finishing diet consisting of cracked corn, soybean meal, and soybean hulls ad libitum for 59 d. Lambs had access to clean water at all times from water fountains. Lambs were weighed on d -1, 1, 14, and 59. On d 59, 16 lambs (8 lambs/treatment) were harvested in the South Dakota State University Meat Lab. Hot carcass weight (HCW), dressing percent (DP), rib fat, body wall thickness, loin eye area, boneless closely trimmed retail cut percentages, and yield grades were recorded. Final body weight (BW), cumulative ADG, and gain efficiency were greater (p ≤ 0.01) for implanted lambs by 2.9%, 25.0%, and 35.2%, respectively, while dry matter intake (DMI) was unaffected by implant treatment (p = 0.18); thus, the efficiency of dietary net energy utilization was increased for IMP (p ≤ 0.01). No appreciable differences were noted (p ≥ 0.17) between treatments for any carcass traits measured. These results indicate that zeranol improves growth performance in heavy finishing lambs without detriment to carcass quality, which implies that producers can improve profitability due to increased gains and efficiency.

This study investigated how different colostrum sources impacted passive immunity transfer and adaptive immune development in Polypay lambs. Newborn lambs were assigned to four groups: fresh ewe colostrum (FrC; n=10), frozen ewe colostrum (FZ; n=11), frozen cattle colostrum (CC; n=11), or artificial cattle colostrum (AC; n=11). Lambs received 65 ml/kg colostrum within 4 hours post-parturition and were raised on milk replacer, creep feed, and hay. IgG concentrations were measured at birth and then weekly until 28 days of age (d). Lambs were immunized with 1mL ovalbumin (2mg/ml in PBS) at 35 and 63 d. Ovalbumin-specific antibodies were quantified. While no significant interaction (P ≥ 0.18) was found for total or relative IgG between FrC and FZ, a tendency (P = 0.06) suggested FrC yielded higher relative IgG at later time points (7, 14, 21, and 28 d). CC resulted in significantly (P = 0.02) higher IgG concen-trations than AC at 24 hours, 7, 14, and 21 d. FrC and AC showed a faster (1 week post immunization) and more robust (> 175%; P ≤ 0.07) ovalbumin humoral response compared to CC lambs 2 to 8 weeks post immunization. No differences were observed in fecal microbiome. This highlights the importance of choosing appropriate colostrum sources for optimal immune devel-opment in lambs.

Using a mixed model, we evaluated effects of national 4-H hippology and livestock skillathon contests on youths' content knowledge, 21st century skills, and postsecondary plans. Hippology participants gained significant knowledge in all topics except breeds, and livestock skillathon contestants gained significant knowledge in all topics. The contests were similar in their effects on development of 21st century skills and postsecondary plans. Gains in content knowledge indicate that contest preparation is an effective method for increasing youths' technical knowledge. Additionally, findings suggest that contest preparation is a viable venue for 21st century skill development and that such skill development is not specific to topic.

This study investigated colostrum source impact on passive immunity transfer and humoral immune development in Polypay lambs. Newborn lambs (4.80 ± 0.33 kg BW) were assigned to four groups: fresh ewe colostrum (FrC; n = 10), frozen ewe colostrum (FZ; n = 11), frozen cattle colostrum (CC; n = 11), or artificial cattle colostrum (AC; n = 11). Lambs received 65 mL/kg colostrum within 4 h post-parturition and were raised on milk replacer, creep feed, and hay until weaned (28 days of age [d]). Immunoglobulin G concentrations were measured at birth and then weekly until 28 d. Lambs were immunized with 1 mL ovalbumin (2 mg/mL PBS) at 35 and 63 d. Ovalbumin-specific antibodies were quantified. A tendency (p = 0.06) suggested FrC yielded higher relative IgG at later time points (7, 14, 21, and 28 d) compared to FZ. Frozen cattle colostrum resulted in significantly (p = 0.02) higher IgG concentrations than AC at 24 h, 7, 14, and 21 d. Fresh ewe colostrum and AC showed a faster (1 week-post-immunization) and more robust (>175%; p ≤ 0.07) ovalbumin humoral response compared to CC lambs 2 to 8 weeks-post-immunization. Fresh ewe colostrum seems to provide the best passive and adaptive immunity compared to other colostrum sources. Moreover, our results suggest that the best colostrum alternative for newborn lambs is frozen ewe colostrum.