Effects of Increasing the Energy Density of a Lactating Ewe Diet by Replacing Hay with Soyhulls (SH) and Dried Distillers Grains with Solubles (DDGS)

Objectives: To evaluate the effects of increasing the ewe’s dietary energy by replacing hay with SH and DDGS on milk production, nutrient composition, lamb growth, and changes in ewe body weight and body condition score (BCS)

A Comparison of Corn or Soybean Hull Based Diets with Dried Distillers Grain with Solubles (DDGS) as the Protein Source in Finishing Diets Comparing Lamb Growth, Feed Efficiency, and Carcass Merit

Objectives: To evaluate growth, carcass merit and mineral status in wether lambs fed finishing diets formulated with dried distillers grain with solubles (DDGS) and soybean hulls (SH)

Effects of Increasing Dietary Energy Density by Replacing Hay with Soyhulls (SH) and Dried Distillers Grains with Solubles (DDGS) on Nutrient Digestibility and Rumen Physiology

Objectives: To determine the effects of increasing dietary energy density in lamb diets from soybean hulls (SH) and dried distillers grain with solubles (DDGS) on nutrient digestibility and rumen physiology

The Presence of Growth Hormone Secretagogue Receptor (ghrelin receptor) in Metabolic Tissues of Beef Cattle with Differences in Composition of Gain

Beef steers (n = 72) of similar age, weight (651 ± 3.1 lb), and genetic (Angus crossbred) background were used to determine the effects of growing diet composition (high‐forage vs. high‐concentrate) on the abundance of growth hormone secretagogue receptor (GHS‐R or ghrelin receptor) in metabolically important tissues of beef cattle. At trial initiation (d 0), 8 steers were harvested for initial carcass composition. The remaining 64 steers were allotted, by weight, to pen and treatment was assigned randomly. Treatments were 1) a high‐forage diet fed during the growing period (116 d) followed by a high‐concentrate diet during the finishing period (117‐209 d; GRW‐FNSH) or 2) a high‐concentrate diet fed for the duration of the trial (0‐209 d; FNSH‐FNSH). Steers were allowed ad libitum consumption regardless of dietary treatment. Eight steers per treatment were harvested on d 88, 116, 165, and 209. Immediately following harvest, liver, muscle (sternomandibularis), and subcutaneous adipose tissue samples were collected from each steer and immersed in liquid nitrogen. Longissimus dorsi samples were collected following a 48 h chill to establish a preliminary analysis of GHS‐R abundance within an economically important muscle tissue. Protein separation and quantification was determined using SDSPAGE and Western blotting techniques. Protein abundance was detected using the LI‐COR® system and standardized to β‐Actin. Protein abundance data were analyzed statistically using the GLM procedure of SAS comparing diet, harvest date, and their interaction. Protein abundance of GHS‐R in longissimus dorsi tissue fluctuated relative to serial harvest date (P \u3c 0.001), and was highest on d 88 in both treatment groups. The FNSH‐FNSH steers had increased abundance of GHS‐R in longissimus dorsi on d 88 and 116 compared with the GRW‐FNSH steers. A dietary treatment by serial harvest day interaction (P \u3c 0.05) occurred for protein abundance of GHS‐R in subcutaneous adipose tissue. Abundance of GHS‐R in subcutaneous adipose tissue of the GRW‐FNSH was greatest on d 88, whereas abundance for the FNSHFNSH treatment was greatest at the end of the finishing period (d 209). An interaction of dietary treatment and serial harvest day resulted (P \u3c 0.05) for GHS‐R abundance in liver tissue. The GRW‐FNSH steers had increased liver GHS‐R abundance following realimentation compared with the FNSH‐FNSH steers which were on a continuous plane of nutrition. Protein abundance for liver GHS‐R in both dietary treatments increased quadraticly (P \u3c 0.001) throughout the feeding period. The GHS‐R was not detected in sternomandibularis tissue. Overall liver GHS‐R abundance increased in both dietary treatments following realimentation which is inconsistent with our hypothesis. Increased GHS‐R abundance in various tissues of beef cattle while ghrelin concentrations are high and excess fat deposition is occurring warrants further investigation

Effects of Dietary Energy Source and Corn Oil Inclusion on Plasma Metabolite and Lipid Profiles and Intramuscular Adipose and Muscle Accretion in Beef Cattle

The objectives of this research were to evaluate 1) fluctuations in plasma metabolites and lipid profiles and 2) differences in satellite cell differentiation and proliferation in cattle with differences in marbling relative to total fatness. Dietary starch is thought to optimize accumulation of marbling. In this experiment, readily fermentable fiber or corn oil were substituted for starch from corn in an effort to alter adipose tissue accretion. Crossbred yearling steers (n = 144) were used in a 131 d finishing trial. The trial was designed as a 3 x 2 factorial arrangement of dietary energy source by corn oil inclusion. Dietary energy sources were the high starch diet which contained 8.5% roughage and 81.2% corn or a higher fiber diet in which chopped, high moisture ear corn (43.7%) and dried corn gluten feed (18.2%) were substituted for corn. Corn germ was included in the diet to provide 0, 2, or 6% corn oil in both the starch and fiber diets. Growth performance and carcass characteristics were recorded and blood samples were collected from each animal on d 96 and 131 of the feeding trial. Previously reported carcass data indicated that dietary energy source (starch vs. fiber) did not influence carcass characteristics. However, as the percentage of corn oil increased with additional amounts of corn germ, marbling scores decreased (P \u3c 0.05) at a constant subcutaneous fat thickness. Compositional analyses support a tendency (P ≤ 0.10) for decreased marbling relative to total carcass fat. Feeding germ increases (P \u3c 0.05) in all components of serum cholesterol. Earlier in the feeding period, GERM also caused higher (P \u3c 0.05) circulating glucose and NEFA concentrations. A sub‐population of steers that were highest (n = 12) and lowest (n = 12) for the relationship of marbling to total carcass fatness (M2Ratio) were scrutinized more closely. Differences in M2Ratio were not associated with HCW or fatness, but were associated with marbling (P \u3c 0.001). Serum collected early in the feeding period from high M2Ratio steers resulted in higher (P \u3c 0.05) satellite cell proliferation and differentiation rates in vitro than serum from low M2Ratio steers. This response diminished with additional days on feed. These results indicate that dietary carbohydrate source has minimal influence on carcass fat distributions, but that dietary oil dramatically alters circulating metabolites and is antagonistic to the production goal of high marbling‐high cutability carcasses

Effects of glycerol and sire breed on growth and carcass traits of finishing wether lambs

Objectives: To evaluate crude glycerin as an energy source for finishing lambs and to determine the effect of sire breed on finishing lamb growth performance and carcass characteristics. In light of previous research, the hypothesis for this experiment was that glycerol would have an energy value similar to that of corn when fed in high concentrate diets to finishing lambs

Effect of Supplemental Fat from Dried Distillers Grains with Solubles or Corn Oil on Nutrient Digestibility

The objective of this experiment was to determine the effects of supplemental fat from either dried distillers grains with solubles (DDGS) or raw corn oil on the digestibility of nutrients and long chain fatty acids. When compared to corn grain and grass hay, DDGS have considerably greater levels of fat, which may negatively influence rumen microbes and nutrient digestibility. Six medium‐framed crossbred steers (initial BW = 602 ± 23.6 lb) were used in a Latin square design to determine apparent total tract digestibility of diets formulated with no supplemental fat or supplemental fat from either DDGS or raw corn oil. Steers were randomly assigned to of 1 of 3 dietary treatments: 1) supplemental fat from DDGS (DG); 2) supplemental fat from corn oil (OIL); 3) no supplemental fat (NO OIL; Table 1). The DG treatment was comprised solely of dried distillers grains with solubles (DDGS). The OIL treatment was comprised of a combination of high‐protein dried distillers grains (HP DDG), corn bran, and corn oil formulated to be isonitrogenous and isolipid to the DG treatment. The final dietary treatment (NO OIL) was a combination of HP DDG and corn bran formulated to be isonitrogenous to the DG and OIL treatments, but with no additional fat. Treatment diets were administered over 3 consecutive 19 d feeding periods that consisted of 14 d diet adaptation followed by 5 d total collection. No differences were observed for DM, OM, ADF, NDF, or N, digestibility. Ether extract digestibility was lower in NO OIL compared to DG and OIL. Apparent digestibility of C17:0 was the lowest for OIL and greatest for DG; NO OIL was intermediate but different from both DG and OIL. C18:0 apparent digestibility was greatest for DG, lowest for OIL; NO OIL was intermediate but not different from either DG and OIL. C18:1c9 digestibility was greatest for DG, intermediate for OIL and least for NO OIL. Apparent digestibility of C20:3, C20:5, C22:2, total C20, and total conjugated linoleic acid were greater in DG and OIL than in NO OIL. These results suggest that providing low concentrations of supplemental fat as either DDGS or raw corn oil to growing steers on high forage diets will not influence digestibilities of DM, OM, ADF, NDF, or N. Digestibilities of ether extract and certain FA are affected by fat inclusion. Low levels of supplemental fat from either DDGS or corn oil may be included in high‐forage rations fed to growing beef steers with no adverse affects on digestibility of nutrients or FA

Effect of Maternal Nutrition on Fetal Adipocyte Development

The objective of this experiment was to determine the effects of maternal nutrition on the expression of genes in fetal tissues. Genes of interest were selected because each has been demonstrated previously to influence body composition. Twenty‐two Angus‐cross bred heifers (BW = 1161 ± 19 lbs) randomly were assigned to three dietary treatments. Maternal dietary treatments were formulated and intake was controlled to provide 150% (HIGH), 100% (INT), and 80% (LOW) of maintenance energy requirements for growing pregnant Angus heifers (NRC, 2000). Heifers were on dietary treatment from d 85 to d 180 of gestation, at which point fetuses were removed via cesarean section and muscle, subcutaneous fat, and liver samples were collected. At trial initiation dam BW was similar between treatment groups. Dam BW differed (P = 0.002) at the end of the treatment period as a result of dietary treatment. Final BW was lowest for the LOW dams, intermediate for INT dams, and highest for HIGH dams. Both ribfat thickness and ribeye area were increased in the HIGH treatment group compared with LOW and INT dams (P \u3c 0.05). Thus, dam growth was influenced by diet during treatment period. Dietary treatment did not influence fetal weight, crown rump length, liver weight, or right hind leg weight of the fetus. Relative gene expression for preadipocyte factor‐1 was more highly expressed (P \u3c 0.05) in HIGH heifers as compared with INT and LOW heifers. These preliminary results suggest that fetal growth characteristics are not affected by manipulation of maternal nutrition during mid‐gestation in beef cows. However, gene expression differences could potentially lead to differences in composition of growth, and warrants further investigation

The Influence of Maternal Energy Status During Mid‐gestationon Beef Offspring Carcass Characteristics and Meat Quality

Research has suggested that maternal under‐nutrition may cause the development of a thrifty phenotype in the offspring, potentially resulting in greater adiposity and reduced muscle mass. These alterations in fat and muscle development could have lasting impacts on offspring growth, carcass characteristics, and meat quality. Thus, the objective of this study was to determine the influence of maternal energy status during mid‐gestation on offspring carcass characteristics and meat quality. To alter maternal energy status, cows either grazed pasture or were fed in a dry‐lot at 80% of the energy requirements for body weight maintenance during a mean period of 109 to 207 d of gestation. Changes in body condition score (BCS), body weight, ribeye area (REA), and 12th rib backfat were measured throughout mid‐gestation and were used to determine cow energy status [Positive (PES) or Negative (NES)]. Cows in the NES group had a significantly greater reduction in BCS, body weight, REA, and 12th rib backfat during mid‐gestation. Maternal energy status had no influence on offspring hot carcass weight, dressing percent, REA, percent kidney, pelvic, and heart fat, marbling score, percent intramuscular fat, objective color, or Warner‐Bratzler shear force. A tendency was seen for NES calves to have improvements in 12th rib backfat and USDA Yield Grade. A greater MRatio and IRatio (calculations used to compare the ratio of marbling (MRatio) and percent intramuscular fat (IRatio) with 12th rib backfat) were discovered in calves from cows experiencing a negative energy status during midgestation. These results suggest that maternal energy status during mid‐gestation may impact fat deposition in intramuscular and subcutaneous fat depots without impacting muscle mass

Relationship of Circulating Ghrelin and Leptin Concentrations in Beef Cattle ExhibitingDifferences in Composition of Gain

Beef steers (n = 72) of similar age, weight (651 ± 3.1 lb), and genetic background (Angus crossbred) were used to determine the effects of growing period diet on the relationship of plasma ghrelin and leptin concentrations with growth performance and carcass composition. At trial initiation (d 0), 8 steers were harvested for initial carcass composition. The remaining 64 steers were allotted, by weight, to pen and treatment was assigned randomly. Treatments were 1) a high‐forage diet fed during the growing period (0‐116 d) followed by a high‐concentrate diet during the finishing period (117‐209 d; GRW‐FNSH) or 2) a high‐concentrate diet fed for the duration of the trial (0‐209 d; FNSH‐FNSH). Steers were allowed ad libitum consumption regardless of dietary treatment. Eight steers per treatment (1 pen) were harvested on d 88, 116, 165, and 209. At each harvest date, 9‐10‐11th rib sections were dissected for chemical composition, and carcass characteristics were recorded. Replicate blood samples were collected from every steer prior to each harvest, and assayed for ghrelin, leptin, GH, insulin, and NEFA concentrations. Hormone, growth performance, and carcass composition were analyzed statistically using the GLM procedure of SAS to evaluate diet, harvest date, and their interaction. Linear, quadratic, and cubic contrasts were performed. Percent carcass protein decreased linearly (P \u3c 0.001) and percent carcass fat increased linearly (P \u3c 0.001) in both treatments. At each harvest day, FNSH‐FNSH steers had greater carcass fat (P \u3c 0.01) compared with GRW‐FNSH steers. Plasma ghrelin concentrations for FNSH‐FNSH increased quadraticly (P \u3c 0.001) over time, whereas plasma ghrelin concentrations were not different over time for GRW‐FNSH. Plasma leptin concentrations for FNSH‐FNSH increased (P \u3c 0.001) from d 0 to 88 and then plateaued, whereas plasma leptin concentrations increased linearly (P \u3c 0.001) for the GRW‐FNSH. Plasma ghrelin and leptin concentrations fluctuated relative to nutritional status, and plasma ghrelin concentrations were highest in excessively fat cattle. The role of ghrelin during fat accumulation warrants further investigation