This study evaluated the effect of feeding a palmitic acid-enriched supplement on production responses and nitrogen metabolism of mid-lactating Holstein and Jersey cows. Eighty mid-lactating dairy cows, 40 Holstein and 40 Jersey, were used in a randomized complete block design with a split-plot arrangement; the main plot was breed and the subplot was fatty acid treatment. Cows within each breed were assigned to 1 of 2 treatments:(1) control diet with no fat supplement or (2) control diet plus a palmitic acid-enriched supplement dosed at 1.5% of diet dry matter (PA treatment). The treatment period was 6 wk with the final 3 wk used for data and sample collection. There were no treatment × breed interactions for the variables analyzed. Compared with control, PA treatment increased milk fat yield (1.36 vs. 1.26 kg/d) and tended to increase 3.5% fat-corrected milk (35.6 vs. 34.0 kg/d) and energy-corrected milk (35.7 vs. 34.1 kg/d). There was no effect of PA treatment on dry matter intake, milk yield, milk protein yield, milk lactose yield, body condition score, body weight (BW) change, nitrogen intake, and variables related to nitrogen metabolism and excretion. Compared with Holstein cows, Jersey cows had greater dry matter intake as a percent of BW (4.90 vs. 3.37% of BW) and lower milk production (29.6 vs. 32.7 kg/d) and milk lactose yield (1.58 vs. 1.42 kg/d), but tended to have greater milk fat yield (1.36 vs. 1.26 kg/d). There was a breed effect on BW change; Holstein cows gained 0.385 kg/d during the experiment, and Jersey cows gained 0.145 kg/d. Jersey cows had lower nitrogen intake (636 vs. 694 g/d), blood urea nitrogen (12.6 vs. 13.8 mg/ dL), urine total nitrogen (125 vs. 145 g/d), and urine total nitrogen as a percent of nitrogen intake (19.5 vs. 21.1%). Overall, feeding a palmitic acid-enriched supplement increased milk fat yield as well as dry matter and fiber digestibility in both Holstein and Jersey cows. The PA treatment did not have any major effects on nitrogen metabolism in both Holstein and Jersey cows. In addition, our results indicated that Jersey cows had lower urinary nitrogen excretion (g/d) than Holstein cows.

Trace minerals are vital for the health and growth of livestock, supporting multiple biochemical processes in the body. There are several different signaling pathways that may be affected by trace minerals, ultimately altering growth of skeletal muscle. However, it is currently unknown how trace minerals specifically impact growth of skeletal muscle. As such, the objective of this study was to determine how zinc (Zn) and manganese (Mn) affect proliferation and protein synthesis of primary bovine satellite cell (BSC) cultures. Cultures were grown to 80% confluency and treated in 1% fetal bovine serum (control), 0.05, 0.10 or 0.25 µM of Mn, or 10, 20 or 40 µM of Zn to assess proliferation. Additionally, the above treatments were applied to fused BSC cultures in serum free media (control) to measure protein synthesis. The trace mineral concentrations chosen were based off known ranges of circulating concentrations of Zn or Mn. A series of contrasts were constructed to determine whether growth of BSC cultures was different between the treated and control cultures. Treatment with 10 µM Zn increased (P = 0.03) proliferation when compared to control cultures. However, treatment with Mn at the tested concentration did not (P > 0.12) result in proliferation rates that were different than the control cultures. Treatment with 10 µM Zn, 20 µM Zn, or 0.5 µM Mn increased (P < 0.05) protein synthesis compared to control cultures. These results indicate Zn is capable of increasing proliferation and both Zn and Mn increase protein synthesis of BSC cultures. Additional research is needed to couple trace mineral nutrition with knowledge of BSC biology to elucidate the molecular mechanisms by which trace minerals may function to support bovine skeletal muscle growth.

Cattle production in the U.S. is being impacted by the changing global climate and limited availability of natural resources. Improving the efficiency of cattle production is imperative to make the most of these limited resources. Increasing the percentage of Bos indicus (BI) genetics within cattle herds is one potential method to address these issues, as they are able to withstand higher temperatures, are better adapted to nutritional stress, and consume less water than Bos taurus (BT) influenced cattle. The objective of this study was to examine steers of different breed types relative to feedlot performance, feeding behavior, and carcass characteristics. This study utilized a total of 115 steers of two different breeds: Angus (AN; n=83; 100% BT) and Santa Gertrudis influenced (SG; n=32; 19% BI, 81% BT). Steers were stratified by weight and randomly divided into one of four covered pens. Each pen was equipped with two GrowSafe bunks and all steers were fed the same typical ration. All steers were harvested at a commercial facility once industry average backfat standards were met. Individual dry matter intake and feeding behaviors were collected through the GrowSafe system. Weight, ribeye fat thickness, marbling score, and USDA yield grades were also assessed. Breed did not have an effect (P >0.10) on dry matter intake, average daily gain, ribeye fat thickness, hot carcass weight, or USDA yield grade. There was a tendency (P=0.09) for SG steers to spend more time with their heads down during individual GrowSafe bunk visits. Intramuscular fat was increased (P=0.0019) in AN steers compared to SG steers. Further research focused on genomic differences between cattle of different breed types is warranted to better understand the relationship between breed type and production performance characteristics.

In some regions of the US, cattle range large areas that do not provide adequate mineral levels and due to the area, mineral supplementation is not possible. Weaned calves from this production system exhibit decreased production performance due to their deficient mineral status. However, there is currently no best practices to supplement these calves with mineral when they are received into a confined feeding setting. As such, this research examined the effects of different mineral supplementation strategies on weight gain, 12th rib fat thickness (REFT) and ribeye area (REA) of sixty feedlot steers obtained from a sale barn in an area known to be mineral deficient. Initially animals were stratified by weight into four different treatment groups (n=15): control (CON), dietary mineral (DM), multimin+dietary mineral (MM+DM), or Multimin (MM) and fed in pens equipped with GrowSafe bunks. Steers received their treatment for the first 40 d of the trial; after this time all steers received the DM treatment. Days 0, 5, 11, 40, 59, 95, 120 and 148 weights were recorded and d 4, 56, and 148 REA and REFT were measured via ultrasound. All data were analyzed using the PROC MIXED procedure of SAS with day as a repeated measure to determine the main effect of treatment. Weight, REA and REFT each increased (P< 0.05) over time. Treatment impacted (P=0.02) weight such that steers receiving the DM treatment gained more (P< 0.05) than those receiving MM+DM and MM, but were no different (P=0.25) than CON steers. Additionally, treatment impacted (P=0.05) REFT such that CON steers had increased (P=0.02) REFT than MM steers, but no other treatment groups were different (P >0.10) from one another. This study suggests that mineral supplementation strategy during the first 40 d of confined feeding may impact production parameters of mineral deficient steers.

Omega-3 fatty acids have immunomodulatory and anti-inflammatory effects. The objective of this project was to determine the effects of fish oil, a source of omega-3 fatty acids, on genes involved in inflammation and growth of skeletal muscle tissue after an LPS challenge. Male Landrace-New Hampshire weaned piglets (BW 8.21±0.83 kg) were used in a randomized complete block design and assigned to two treatments: 1) basal diet (n=7) and 2) basal diet plus 3% fish oil added (n = 7). Treatments were fed for 35 d. On d 34, an LPS challenge was performed and 24 h later, piglets were euthanized and skeletal muscle samples were collected from the longissimus lumborum and biceps femoris. Total mRNA was isolated and markers of inflammation [cyclophilin (Cyclo), nuclear factor kappa beta subunit-1 (NF-kB), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6)], skeletal muscle growth [paired box transcription factor-7 (Pax7), myogenic factor-5 (Myf5), myoblast determination factor-1 (MyoD), myogenin (MyoG)] and adipose growth (peroxisome proliferator activated receptor (PPARy), leptin, and adiponectin) were analyzed. Cyclophilin abundance was increased (P = 0.03) in fish-oil piglets compared to control piglets. Other markers of inflammation (TNF-α, IL-6, NF-kB) were not affected (P > 0.05) by fish-oil supplementation. Abundance of Myf5 was lower (P = 0.03) in fish oil piglets than control piglets. Other myogenic regulatory factors (Pax7, MyoD, MyoG) were not (P > 0.05) altered by treatment. Abundance of PPARy, leptin or adiponectin was not affected (P > 0.05) by fish-oil supplementation. Muscle location influenced (P < 0.01) abundance of leptin and adiponectin, with abundance being higher in the biceps femoris than in the longissimus lumborum. No other genes analyzed were impacted by muscle location (P > 0.05). Our findings suggest that supplementation of omega-3 fatty acids via fish-oil may affect the inflammatory response and skeletal muscle growth. Further research is needed to evaluate the impact of these results on animal production.