M. F. Montano

Effect of Variation in Supplement Inclusion Rate and Laidlomycin Propionate on Growth Performance of Feedlot Cattle

Abstract Montano, M.F., Loya-Olguin, J.L., Plascencia, A., Salinas Chavira, J. and Zinn, R.A. 2010. Effect of variation in supplement inclusion rate and laidlomycin propionate on growth performance of feedlot cattle. J. Appl. Anim. Res., 37: 83–87. One hundred twelve yearling steers (364±3.4 kg) were used in a 123-d finishing trial to evaluate the interaction of laidlomycin propionate and variation in supplement inclusion rate on growth performance and carcass characteristics. Two levels of laidlomycin propionate (0 vs. 10 mg/kg) and two levels of variation in daily supplement (12 g urea, 18 g limestone, 2 g Mg02 and 5 g trace mineralized salt) inclusion rate (O vs 20% coefficient of variation) were evaluated in a 2x2 factorial arrangement. Variation was produced by altering the inclusion rate of the supplement portion of the diet to achieve a 20% CV in supplement concentration of the complete mixed, as follows: on d 1 and 5 of each week the diet contained 125% of the specified amount of supplement; on d 2, 4 and 6 the diet contained 100% of the specified amount of supplement; on d 3 and 7 the diet contained 75% of the specified amount of supplement. There were no treatment interactions (P<0.20). Variation in supplement inclusion rate decreased ADG (8%, P<0.05), gain efficiency (G:F; 5%, P<0.01), dietary NEm (2.3%, P<0.01) and dietary NEg (3.3%, P<0.01). Supplemental laidlomycin tended to increase ADG (6%, P=0.19), but did not affect (P<0.20) gain efficiency or dietary NE. There were no treatment effects (P<0.20) on carcass characteristics. It is concluded that variation in supplement inclusion may depress growth performance of feedlot cattle, attributable to reduction in both energetic efficiency and DMI.

Effects of monensin and virginiamycin supplementation in finishing diets with distiller dried grains plus solubles on growth performance and digestive function of steers

Two trials were conducted to evaluate the influence of virginiamycin (26 mg/kg) and monensin (34 mg/kg) supplementation of a steam-flaked corn-based finishing diet containing 15% distiller dried grains plus solubles (DDGS) on growth performance and digestive function. In Trial 1, 135 steers (257 ± 21 kg) were used to evaluate treatment effects on 145-d growth performance. There were no treatment effects (P > 0.20) on dry matter intake (DMI). Antibiotic supplementation tended to increase average daily gain (ADG; 7%, P = 0.07); increased gain efficiency (11%, P < 0.01) and estimated dietary net energy (NE; 10%, P < 0.01). Carcass marbling score was greater (12%, P = 0.04) for virginiamycin vs. monensin. In Trial 2, three Holstein steers (300 ± 7 kg) were used in a 3 × 3 Latin square to evaluate treatment effects on digestion. Both monensin and virginiamycin depressed ruminal digestion of organic matter (OM; 6%, P < 0.01) and feed nitrogen (N, 15%, P = 0.03) and microbial protein synthesis (15%, P = 0.03). There were no treatment effects of total tract OM and N digestion. Antibiotic supplementation increased (2.3%, P = 0.02) ruminal pH, associated with decreased (7%, P = 0.04) ruminal volatile fatty acids (VFA) concentrations. It is concluded that monensin and virginiamycin supplementation of growing-finishing diets for feedlot cattle may enhance daily weight gain, gain efficiency and dietary energetics. These effects are associated with a shift towards great intestinal OM digestion and decreased ruminal degradation of feed N and microbial protein synthesis.

Influence of protein nutrition and virginiamycin supplementation on feedlot growth performance and digestive function of calf-fed Holstein steers

Two experiments were conducted to examine the influence of protein and virginiamycin (VM) supplementation on feedlot growth performance, digestion, and metabolizable AA (MAA) supply of calf-fed Holstein steers. Growth performance and dietary energetics were evaluated in 120 Holstein steers (127 ± 9 kg). During the initial 112-d feeding period, a steam-flaked corn-based diet was balanced to meet either 100% (MAB) or 87% (UREA) of MAA requirements. Diets were supplemented with or without 22.5 mg/kg VM in a 2 × 2 factorial arrangement. Subsequently (d 112 to 308), all steers received the UREA diet with or without VM. During the initial 112-d, MAB increased ADG, G:F, and dietary NE ( < 0.01). Thereafter, when all steers received the UREA diet, ADG, G:F, and dietary NE were not different ( > 0.10) across initial supplementation treatments. Overall (d 1 to 308), MAB did not affect ADG ( > 0.10) but enhanced G:F efficiency ( = 0.03) and dietary NE ( = 0.05). During the initial 112-d period and through the remainder of the experiment, VM increased G:F ( < 0.01) and dietary NE ( < 0.01). Four Holstein steers (146 ± 4 kg) with cannulas in the rumen and proximal duodenum were used in a 4 × 4 Latin square design to evaluate initial 112-d treatment effects on digestive function. There were no treatment effects ( > 0.10) on ruminal digestion of OM, NDF, starch, microbial efficiency, or total tract digestion of OM and NDF. The MAB increased indispensable AA flow to the small intestine ( < 0.01) and total tract digestion of N ( < 0.01) and starch ( = 0.04). Observed AA supply to small intestine was in agreement with expected supply ( = 0.96). Virginiamycin decreased ( = 0.04) nonammonia N flow to the small intestine and did not affect ( > 0.10) total tract N digestion. Extrapolating from AA supplies in the metabolism study, MAB satisfied indispensable AA requirements during the initial 112-d period, whereas the UREA diet met 73.5% and 79.2% of methionine and lysine requirements, respectively. During the subsequent periods (d 112 to 308) indispensable AA supplies exceeded theoretical requirements. We conclude that enhancements in energy utilization when diets are balanced to meet MAA requirements of calf-fed Holstein steers during the initial 112-d feedlot period remain appreciable throughout time on feed. Virginiamycin enhanced efficiency of energy utilization throughout the feedlot growing-finishing period.

Influence of ruminal degradable intake protein restriction on characteristics of digestion and growth performance of feedlot cattle during the late finishing phase

Two trials were conducted to evaluate the influence of supplemental urea withdrawal on characteristics of digestion (Trial 1) and growth performance (Trial 2) of feedlot cattle during the last 40 days on feed. Treatments consisted of a steam-flaked corn-based finishing diet supplemented with urea to provide urea fermentation potential (UFP) of 0, 0.6, and 1.2%. In Trial 1, six Holstein steers (160 ± 10 kg) with cannulas in the rumen and proximal duodenum were used in a replicated 3 × 3 Latin square experiment. Decreasing supplemental urea decreased (linear effect, P ≤ 0.05) ruminal OM digestion. This effect was mediated by decreases (linear effect, P ≤ 0.05) in ruminal digestibility of NDF and N. Passage of non-ammonia and microbial N (MN) to the small intestine decreased (linear effect, P = 0.04) with decreasing dietary urea level. Total tract digestion of OM (linear effect, P = 0.06), NDF (linear effect, P = 0.07), N (linear effect, P = 0.04) and dietary DE (linear effect, P = 0.05) decreased with decreasing urea level. Treatment effects on total tract starch digestion, although numerically small, likewise tended (linear effect, P = 0.11) to decrease with decreasing urea level. Decreased fiber digestion accounted for 51% of the variation in OM digestion. Ruminal pH was not affected by treatments averaging 5.82. Decreasing urea level decreased (linear effect, P ≤ 0.05) ruminal N-NH and blood urea nitrogen. In Trial 2, 90 crossbred steers (468 kg ± 8), were used in a 40 d feeding trial (5 steers/pen, 6 pens/ treatment) to evaluate treatment effects on final-phase growth performance. Decreasing urea level did not affect DMI, but decreased (linear effect, P ≤ 0.03) ADG, gain efficiency, and dietary NE. It is concluded that in addition to effects on metabolizable amino acid flow to the small intestine, depriving cattle of otherwise ruminally degradable N (RDP) during the late finishing phase may negatively impact site and extent of digestion of OM, depressing ADG, gain efficiency, and dietary NE.

Influence of Wheat Straw Pelletizing and Inclusion Rate in Dry Rolled or Steam-flaked Corn-based Finishing Diets on Characteristics of Digestion for Feedlot Cattle

Eight Holstein steers (216±48 kg body weight) fitted with ruminal and duodenal cannulas were used to evaluate effects of wheat straw processing (ground vs pelleted) at two straw inclusion rates (7% and 14%; dry matter basis) in dry rolled or steam-flaked corn-based finishing diets on characteristics of digestion. The experimental design was a split plot consisting of two simultaneous 4×4 Latin squares. Increasing straw level reduced ruminal (p<0.01) and total tract (p = 0.03) organic matter (OM) digestion. As expected, increasing wheat straw level from 7% to 14% decreased (p<0.05) ruminal and total tract digestion of OM. Digestion of neutral detergent fiber (NDF) and starch, per se, were not affected (p>0.10) by wheat straw level. Likewise, straw level did not influence ruminal acetate and propionate molar proportions or estimated methane production (p>0.10). Pelleting straw did not affect (p≥0.48) ruminal digestion of OM, NDF, and starch, or microbial efficiency. Ruminal feed N digestion was greater (7.4%; p = 0.02) for ground than for pelleted wheat straw diets. Although ruminal starch digestion was not affected by straw processing, post-ruminal (p<0.01), and total-tract starch (p = 0.05) digestion were greater for ground than for pelleted wheat straw diets, resulting in a tendency for increased post-ruminal (p = 0.06) and total tract (p = 0.07) OM digestion. Pelleting wheat straw decreased (p<0.01) ruminal pH, although ruminal volatile fatty acids (VFA) concentration and estimated methane were not affected (p≥0.27). Ruminal digestion of OM and starch, and post-ruminal and total tract digestion of OM, starch and N were greater (p<0.01) for steam-flaked than for dry rolled corn-based diets. Ruminal NDF digestion was greater (p = 0.02) for dry rolled than for steam-flaked corn, although total tract NDF digestion was unaffected (p = 0.94). Ruminal microbial efficiency and ruminal degradation of feed N were not affected (p>0.14) by corn processing. However, microbial N flow to the small intestine and ruminal N efficiency (non-ammonia N flow to the small intestine/N intake) were greater (p<0.01) for steam-flaked than for dry rolled corn-based diets. Ruminal pH and total VFA concentration were not affected (p≥ 0.16) by corn processing method. Compared with dry rolled corn, steam-flaked corn-based diets resulted in decreased acetate:propionate molar ratio (p = 0.02). It is concluded that at 7% or 14% straw inclusion rate, changes in physical characteristics of wheat straw brought about by pelleting negatively impact OM digestion of both steam-flaked and dry-rolled corn-based finishing diets. This effect is due to decreased post-ruminal starch digestion. Replacement of ground straw with pelleted straw also may decrease ruminal pH.

Effect of energy density and virginiamycin supplementation in diets on growth performance and digestive function of finishing steers

Objective This study was determined the influence of virginiamycin supplementation on growth-performance and characteristics of digestion of cattle with decreasing dietary net energy value of the diet for maintenance (NEm) from 2.22 to 2.10 Mcal/kg. Methods Eighty crossbred beef steers (298.2±6.3 kg) were used in a 152-d performance evaluation consisting of a 28-d adaptation period followed by a 124-d growing-finishing period. During the 124-d period steers were fed either a lesser energy dense (LED, 2.10 Mcal/kg NEm) or higher energy dense (HED, 2.22 Mcal/kg NEm) diet. Diets were fed with or without 28 mg/kg (dry matter [DM] basis) virginiamycin in a 2×2 factorial arrangement. Four Holstein steers (170.4±5.6 kg) with cannulas in the rumen (3.8 cm internal diameter) and proximal duodenum were used in 4×4 Latin square experiment to study treatment effects on characteristics of digestion. Results Neither diet energy density nor virginiamycin affected average daily gain (p>0.10). As expected, dry matter intake and gain efficiency were greater (p<0.01) for LED- than for HED-fed steers. Virginiamycin did not affect estimated net energy value of the LED diet. Virginiamycin increased estimated NE of the HED diet. During daylight hours when the temperature humidity index averaged 81.3±2.7, virginiamycin decreased (p<0.05) ruminal temperature. Virginiamycin did not influence (p>0.10) ruminal or total tract digestion. Ruminal (p = 0.02) and total tract digestion (p<0.01) of organic matter, and digestible energy (p<0.01) were greater for HED vs LED. Ruminal microbial efficiency was lower (p<0.01) for HED vs LED diets. Conclusion The positive effect of virginiamycin on growth performance of cattle is due to increased efficiency of energy utilization, as effects of virginiamycin on characteristics of digestion were not appreciable. Under conditions of high ambient temperature virginiamycin may reduce body temperature.

Influence of kaolinite clay supplementation on growth performance and digestive function in finishing calf-fed Holstein steers.

Two experiments were conducted to examine the influence of kaolinite clay supplementation (0%, 1%, or 2% diet dry matter [DM] basis) on characteristics of digestion (Trial 1) and growth performance (Trial 2) in calf-fed Holstein steers fed a finishing diet. In Trial 1, 6 Holstein steers (539±15 kg) with ruminal and duodenal cannulas were used to evaluate treatment effects on characteristics of digestion. Kaolinite clay supplementation decreased total tract DM digestion (linear effect, p<0.01) without effects (p≥0.10) on site and extent of digestion of organic matter, neutral detergent fiber, starch and N, or ruminal microbial efficiency. There were no treatment effects on ruminal pH, volatile fatty acids molar proportions or estimated methane production. In Trial 2, 108 Holstein steers (132.4±5.6 kg) were used in a 308-d study to evaluate growth performance and carcass characteristics. There were no treatment effects (p>0.10) on average daily gain (ADG) and gain efficiency (ADG/dry matter intake). Kaolinite supplementation tended (linear effect, p = 0.08) to increase dietary net energy (NE) during the initial 112-d period. However, the overall (308-d) effect of supplementation dietary NE was not appreciable (p>0.20). However, due to the inertness of kaolinite, itself, the ratio of observed-to-expected dietary NE increased with kaolinite supplementation. This effect was more pronounced (linear effect, p 0.03) during the initial 224 d of the study. Overall (308 d), kaolinite supplementation tended to increase (linear effect, p = 0.07) dietary NE by 3% over expected. Kaolinite supplementation did not affect carcass weight, yield grade, longissimus area, kidney, pelvic and heart fat, and quality grade, but decreased (linear effect, p = 0.01) dressing percentage. It is concluded that kaolinite supplementation up to 2% of diet DM may enhance energetic efficiency of calf-fed Holstein steers in a manner independent of changes in characteristics of ruminal and total tract digestion.

Influence of feeding enzymatically hydrolysed yeast cell wall + yeast culture on growth performance of calf-fed Holstein steers

ABSTRACT One hundred and sixty-eight crossbred steers (133 ± 7 kg) were used in a 336-d experiment to evaluate the effects of enzymatically hydrolysed yeast cell wall plus yeast culture (EHY) supplementation on growth performance and carcass characteristics. Treatments consisted of steam-flaked corn-based diet supplemented with 0, 195, 390 or 585 mg/kg EHY. Supplemental EHY enhanced overall (336-d) dry matter intake (DMI, P < .01), averagde daily gain (ADG, P = .04), and final carcass weight (P = .04). Responses were maximal (quadratic effect, P ≤ .02) at the 195 mg/kg level of EHY supplementation. Feed intake enhancements were observed throughout each 112-d period of the study. Improvements in ADG were largely the result of increased DMI, as gain efficiency and estimated dietary net energy (NE) were not affected by EHY supplementation. Effects of supplemental EHY on other carcass measures were not appreciable (P > .20), except for a slight lowering (0.7%, P = .04) in carcass yield. We conclude that throughout the growing-finishing period, supplemental EHY will enhance ADG, resulting in marked increases in final carcass weight. This effect is due to consistent increases in DMI, as supplementation did not affect gain efficiency or estimated dietary NE.

Influence of flake density and tempering on the feeding value of steam-flaked corn for feedlot cattle

ABSTRACT A feedlot growth-performance trial was conducted to evaluate the relative response to tempering when flake density (FD) of corn is increased from 0.31 kg/L (24 lb/bushel) to 0.39 kg/L (30 lb/bushel). Treatments were (1) non-tempered, FD = 0.31 kg/L; (2) non-tempered, FD = 0.39 kg/L; (3) tempered, FD = 0.31 kg/L and (4) tempered, FD = 0.39 kg/L. Tempering prior to flaking increased (21%, P < .01) the moisture content of corn as it exited the rolls and decreased (14%, P = .02) the starch enzymatic reactivity. Increasing roll tension to reduce FD decreased flake thickness (24%, P < .01) and increased starch reactivity (43%, P < .01). Increasing FD decreased (P = .03) estimated dietary NEm and NEg, and the estimated NEm and NEg values of steam-flaked corn by 2.3% and 2.9%, respectively. We conclude that whereas tempering corn grain before steam flaking increases the moisture content of corn as it exits the roles, it has minimal influence on the feeding value for corn for feedlot cattle. Increasing FD from 0.31 to 0.39 kg/L decreases starch reactivity and the net energy value of corn, but does not affect daily weight gain or carcass characteristics.

Evaluation of supplemental vitamin E on 56-day feedlot growth performance and plasma tocopherol concentrations in calf-fed Holstein steers

ABSTRACT Fifty-four Holstein steer calves, divided in two weight groupings (141.2 ± 4.9 kg and 454.2 ± 7.0 kg respectively), were used in a 56-day study to evaluate the influence of supplemental vitamin E on growth performance and plasma vitamin concentrations. Steers were assigned within body weight groupings to 18 pens, 3 steers/pen. Dietary treatments consisted of a steam-flaked corn-based growing-finishing diet supplemented to provide 0, 250, or 500 IU/d of vitamin E as all racemic α-tocopherol. No morbidity was apparent during the course of the study. Calves in the heavier weight grouping had greater average daily gain (24.4%, P < .01), dry matter intake (54.3%, P < .01), and lower gain efficiency (40.7%, P < .01). Vitamin E supplementation did not affect (P > .10) feedlot growth performance. Initial and 56-day plasma tocopherol were not influenced (P > .10) by weight grouping. Final 56-day plasma tocopherol increased linearly (P < .01) with level of vitamin E supplementation. Plasma tocopherol of non-supplemented steers decreased (P = .01) from an average initial concentration of 1.66–1.16 ug/mL at day 56. It is concluded that vitamin E supplementation of calf-fed Holstein steers receiving a conventional steam-flaked corn-based growing-finishing diet is not expected to enhance growth performance.