Performance of feedlot steers fed diets containing laidlomycin propionate or monensin plus tylosin, and effects of laidlomycin propionate concentration on intake patterns and ruminal fermentation in beef steers during adaptation to a high-concentrate diet

Abstract Finishing cattle are fed high concentrate diets to increase deposition of both muscle and adipose tissue and decrease cost of gain. The objective of this experiment was to evaluate the effects of increased roughage inclusion late in the finishing period on growth performance, carcass traits, and ruminal and fecal characteristics of feedlot steers. Treatments included a control (CON; 6% roughage DM), intermediate (INT; 12% roughage DM), and high (HGH; 18% roughage DM) roughage diets. Crossbred beef steers (n = 54; BW = 289 ± 35.6 kg) were assigned to treatments for the late finishing period in a randomized complete block design (4 pens of INT and HGH, 5 pens of CON; 4 steers per pen). Experimental diets contained prairie hay, Sweet Bran, rolled corn, dry supplement, urea, and a corn steep and molasses-based liquid supplement. The inclusion rate of roughage and rolled corn were adjusted for each treatment diet. Steers in HGH tended to have increased overall DMI (P = 0.07). No differences in final BW, overall ADG, or gain:feed were observed among treatments (P ≥ 0.72). Steers fed HGH had the greatest REA (P = 0.03) and a tendency for a lower yield grade (P = 0.08). Fat thickness, HCW, marbling, liver scores, and KPH did not differ (P ≥ 0.29) among treatments. Steers fed the HGH diet had a lower fecal pH at the end of finishing (P = 0.05) compared to CON and INT steers. Ruminal lactate was increased on d 14 for CON steers compared to other treatments (P < 0.001). No differences were observed for ruminal pH (P ≥ 0.11). Results of this experiment suggest that increasing roughage late in the finishing period does not negatively impact growth performance or carcass characteristics, but may alter ruminal fermentation and post ruminal digestion.

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EFFECT OF CHOLINE IN ALL-CONCENTRATE DIETS OF FEEDLOT STEERS AND ON RUMINAL ACIDOSIS

Canadian Journal of Animal Science ◽

10.4141/cjas85-014 ◽

1985 ◽

Vol 65 (1) ◽

pp. 135-146 ◽

Cited By ~ 3

Author(s):

T. S. RUMSEY

Keyword(s):

Lactic Acid ◽

Lactic Acidosis ◽

Latin Square ◽

Serum Glucose ◽

Beef Steers ◽

Ruminal Fermentation ◽

Plasma Urea ◽

Ruminal Acidosis ◽

Feedlot Steers ◽

Made In

Four trials with beef steers were conducted to determine if choline supplementation of an all-concentrate diet improved performance and affected ruminal lactic acidosis. Trial 1 was a preliminary feeding trial with 12 individually fed steers averaging 356 kg initial body weight. Trials 2 and 3 were feedlot trials with 64 and 80 steers averaging 359 and 320 kg initial body weights, respectively. Trial 4 was an intensive trial with three ruminal-fistulated steers in a 3 × 3 Latin square design in which subacute ruminal acidosis was produced. Choline supplementation neither consistently affected feedlot performance and carcass merit measurements in the feeding trials, nor consistently affected end products of ruminal fermentation. Choline appeared to reduce total plasma amino acids and increase plasma urea (measurements made in Trials 2 and 3) and reduce serum glucose, triglycerides and glutamic pyruvic transaminase while increasing serum total lipids and cholesterol (measurements made in Trial 3). Choline did not affect ruminal volatile fatty acid, pH, ammonia and lactic acid isomer changes associated with subacute lactic acidosis. The results indicate that the levels of choline supplementation of an all-concentrate diet for beef steers used in this study did not affect ruminal acidosis and did not improve performance of feedlot steers. Key words: Choline, acidosis, lactic acid, rumen, steer, beef cattle

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Effects of roughage type on particle separation, rumination, fiber mat characteristics, in situ degradation, and ruminal fermentation parameters in beef steers

Journal of Animal Science ◽

10.1093/jas/skab214 ◽

2021 ◽

Author(s):

Catherine L Lockard ◽

Caleb G Lockard ◽

Wyatt N Smith ◽

Kendall J Karr ◽

Ben P Holland ◽

...

Keyword(s):

Dry Matter ◽

Rumen Fluid ◽

Fluid Collection ◽

Latin Square ◽

Experimental Unit ◽

Beef Steers ◽

Ruminal Fermentation ◽

In Situ Degradation ◽

Fermentation Parameters

Abstract Six ruminally cannulated steers (average BW = 791 + 71 kg) were used in a replicated 3 × 3 Latin square experiment to determine the effects of roughage type on rumination, fiber mat characteristics, and rumen fermentation variables. Three roughages were included at 7% (DM basis) in a steam flaked corn-based diet; cotton burrs (CB), wheat silage (WS), or corn stalks (CS). Steers were fitted with a sensory collar to record rumination behaviors in 2-h intervals at the beginning of the experiment. Each 30-d period consisted of a 7-d of recovery, 14-d of diet adaptation, 7-d of rumination data collection (daily and bi-hourly average rumination), 1-d of rumen fluid collection, and 1-d of rumen evacuations. In situ degradation of individual roughages was determined for 4-d after period 3 evacuations. During rumen evacuations, ruminal contents were removed; the rumen fiber mat (RF) was separated from the liquid portion with a 2 mm sieve, weighed, and a subsample was dried. Data were analyzed using the MIXED procedure of SAS with steer as the experimental unit and roughage (CB, WS, and CS) as the main effect. Dry matter intake (DMI) was not different for CB and WS (P = 0.25) and greatest for steers consuming CS diet (P < 0.01). Roughage type did not influence the weight of the RF dry matter (%; DM; P = 0.92), RF weight (P = 0.69), or RF:DMI ratio (P = 0.29). Daily rumination (min/d) did not differ among roughages (P = 0.40), but min of rumination/kg of DMI was greatest for CS (18.0 min), min/kg of NDF was greatest for WS (89.8 min; P = 0.02), and min/kg of peNDF was greatest for CS (132.4 min; P < 0.01). Wheat silage had the greatest percentage of soluble DM and CB-R and CS-R (P < 0.01) had the greatest ruminal degraded DM fraction. Rumen fiber mat did not differ for roughages, although rumination min/kg of DMI and peNDF was greatest for steers consuming CS and WS. In situ degradation determined that CB-R and CS-R had the greatest percentage of ruminal degraded DM. Based on the objective of the experiment, roughage type did not influence daily rumination or fiber mat characteristics.

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Impact of a mixed culture of Lactobacillus casei and L. lactis on in vitro ruminal fermentation and the growth of feedlot steers fed barley-based diets

Canadian Journal of Animal Science ◽

10.4141/cjas08117 ◽

2009 ◽

Vol 89 (2) ◽

pp. 263-271 ◽

Cited By ~ 5

Author(s):

J. Baah ◽

Y. Wang ◽

T A McAllister

Keyword(s):

Growth Performance ◽

Mixed Culture ◽

Lactobacillus Casei ◽

Carcass Characteristics ◽

Barley Grain ◽

Feedlot Cattle ◽

Ruminal Fermentation ◽

Feedlot Steers ◽

Barley Silage

The effect of a direct-fed microbial (DFM) poduct containing a mixed culture of Lactobacillus casei and L. lactis on in vitro ruminal fermentation of barley-grain/barley-silage-based backgrounding and finishing diets and on growth performance and carcass characteristics of feedlot cattle was evaluated during backgrounding (84 d) and finishing (140 d) of 100 Hereford × Angus steers (initial body weight = 280 ± 15.5 kg). The inclusion rates of DFM in the in vitro study were 4, 8, 12 and 16 million colony forming units (CFU) of lactic acid bacteria (LAB) kg-1 DM of substrate. Total in vitro volatile fatty acids (VFA) production increased at 6 and 12 h of incubation (P < 0.01; linear response) when the backgrounding diet was supplemented with DFM. Dry matter digestibility and VFA production also increased (P < 0.05) during a 12-h fermentation of the finishing diet. Steers were randomly allocated to one of four dietary treatments that comprised feeding DFM tp provide 0 (control), 4 × 107, 8 × 107, or 12 × 107 CFU kg-1 diet DM. Average daily gain (ADG, kg) and feed efficiency (G:F; kg gain kg-1 DM consumed) of steers improved (P = 0.002 and 0.001, respectively) as a result of feeding DFM during the backgrounding period, but not during the finishing period. Saleable meat and rib eye area decreased (P = 0.038, linear; and P = 0.041, quadratic) with DFM supplementation. The results indicated that supplementing barley-grain/barley-silage-based feedlot cattle diets with 12 × 107 CFU of the mixed culture of lactobacilli used in these studies could improve ruminal fermentation, ADG and G:F in backgrounding feedlot steers. However, supplementation during the finishing period may not be warranted in terms of growth performance and carcass characteristics. Differences in the microbial ecology of the intestinal tract as a result of differences in diet composition may account for the varied response between the backgrounding and finishing periods.Key words: Beef cattle, direct-fed microbial, growth performance, Lactobacillus casei, Lactobacillus lactis, ruminal fermentation

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