F. E. Keomanivong

Influence of forage source and forage inclusion level on growth performance, feeding behavior, and carcass characteristics in finishing steers

Two experiments were conducted to determine the effects of forage source (Exp. 1) and forage inclusion level (Exp. 2) in finishing diets on growth performance and feeding behavior. In Exp. 1, sixty-four steers (394 ± 3.6 kg BW) were allotted by BW to 3 pens. Within each pen, steers were assigned randomly to 1 of 4 dietary treatments containing different forage sources: 1) alfalfa hay, 2) corn silage, 3) wheat straw, and 4) corn stover. Alfalfa hay was provided at 10% of the diet DM and the other forage sources were offered to provide the same percentage of NDF from forage. In Exp. 2, forty-four steers (451 ± 4.6 kg BW) were used in a completely randomized design and were fed dry-rolled corn-based diets containing a mixture of hay and corn silage as the forage source at 5%, 10%, 15%, or 20% forage (DM basis). Intake and feeding behavior traits were calculated from data generated by the Insentec feeding system. In Exp. 1, final BW, ADG, and G:F did not differ between treatments. Dry matter intake and feeding behavior traits responded differently depending on week (interaction ≤ 0.04) of the experiment with DMI generally greater in steers fed alfalfa or corn silage early in the experiment and time per meal generally greater and eating rate slower in steers fed diets containing wheat straw or corn stover. In Exp. 2, ADG and G:F decreased linearly ( < 0.001) with increasing forage inclusion. Quadratic effects ( ≤ 0.002) were observed for eating time (per visit, meal, and d) and DMI (per visit, meal, and min) with eating time greatest in the 10% forage treatment and DMI the least in the 20% forage treatment. Dry matter intake per d responded differently depending on week (interaction = 0.01) with some weeks exhibiting linear and other quadratic effects that were primarily the result of the largest decrease in DMI in the 20% forage inclusion treatment. These data indicate that growth performance was not influenced by forage source, when fed at a similar NDF inclusion level, but was negatively impacted by increasing forage inclusion in high-concentrate finishing diets. However, both forage source and inclusion level impacted feeding behavior as cattle consuming bulkier forages (wheat straw or corn stover) or at greater inclusion levels typically had a slower eating rate and took longer to consume a meal. Additionally, DMI may decrease at greater forage inclusion levels (> 15%).

Effect of grain type and dried distillers grains plus solubles oil concentration on site of digestion in cattle fed finishing diets

Abstract: The objective of this experiment was to determine the effects of grain type (rolled corn vs. rolled barley) and oil concentration of dried corn distillers grains plus solubles (DDGS; moderate = 7.9% vs. low = 4.5% ether extract) on site of digestion. Seven ruminally and duodenally cannulated Holstein steers (716 ± 8.9 kg) were used in a 4 × 7 Youden square with experimental periods of 24 d. True ruminal organic matter (OM) and crude protein (CP) digestibility (% of intake) as well as intestinal (% of entering duodenum) and total tract starch digestibility was greater (P ≤ 0.03) in steers fed diets containing barley than in steers fed diets containing corn. Ruminal disappearance and ruminal, intestinal, and total tract OM, CP, and starch digestibility were not influenced (P ≥ 0.11) by feeding diets containing DDGS with differing oil concentration. Total tract lipid digestibility (%) was greater (P < 0.001) in steers fed diets containing moderate-oil DDGS than low-oil DDGS. These data indicate that including a low-oil DDGS, as compared with a moderate-oil DDGS, in finishing diets containing rolled corn or rolled barley does not influence intake or site of digestion of nonlipid components.

Influence of grain source and dried corn distillers grains plus solubles oil concentration on finishing cattle performance and feeding behavior

Abstract: Eighty-one steers [428 ± 3.5 kg of body weight (BW)] were used to determine the effect of grain type (corn vs. barley) and oil concentration of dried corn distillers grains plus solubles (DDGS; moderate = 7.9% vs. low = 4.5% ether extract) on growth performance, feeding behavior, and carcass characteristics. Intake and feeding behavior traits were calculated from data generated via the Insentec feeding system. Steers were slaughtered with an average BW of 668 ± 4.4 kg. Final BW and average daily gain (ADG) were not affected by grain type or DDGS oil concentration. Dry matter intake (DMI) decreased (P = 0.002) and gain:feed ratio (G:F) increased (P = 0.01) in steers fed diets containing barley. Daily visits to the feeder decreased (P = 0.05), but time eating per visit increased (P = 0.03) in steers fed diets containing barley than corn. Plasma urea–N concentration was greater (P ≤ 0.05) in steers fed diets containing barley than corn and in steers fed diets containing low-oil DDGS than moderate-oil DDGS diets. There was no effect of treatment on carcass characteristics. These data indicate that steers fed diets containing barley had improved G:F and that including low-oil vs. moderate-oil DDGS in a finishing diet does not influence growth performance, feeding behavior, or carcass measurements.

The influence of pregnancy and plane of nutrition during pregnancy on pancreatic digestive enzymes and insulin-containing cell cluster morphology in beef cows

Abstract: To determine effects of pregnancy (experiment 1) and plane of nutrition during pregnancy (experiment 2) on pancreatic digestive enzymes and morphology of insulin-containing cell clusters, beef cows were slaughtered, and the pancreas collected 4 wk before parturition (if pregnant or similar time on feed for nonpregnant cows). In experiment 1, mature, nonlactating cows [717 ± 70 kg; nine pregnant (PREG) and nine nonpregnant (OPEN)] were used. In experiment 2, nonlactating, pregnant cows (639 ± 68 kg) were fed at 85% (n = 11; LOW) or 140% (n = 11; HIGH) of net energy (NE) requirements. Concentration (U g-1) and content (U kg-1 BW) of α-amylase and trypsin activities were greater (P ≤ 0.05) in OPEN than PREG cows. Pregnant cows had greater (P ≤ 0.03) insulin-cell cluster size and proportion of large insulin-containing cell clusters than OPEN cows. Concentration and content of α-amylase activity were greater (P ≤ 0.04) in HIGH than LOW cows. These data indicate that pregnancy status (PREG vs. OPEN) impacts pancreatic exocrine and endocrine functions and that plane of nutrition (85% vs. 140% of NE requirements) of pregnant cows may not greatly impact pancreatic exocrine and endocrine functions.