Diet Composition and Dry Matter Intake of Beef Steers Grazing Tall Fescue and Alfalfa

Abstract There is a lack of consistency across the globe in how countries establish tissue ractopamine residue limits and which residue limits are applied to various tissues, particularly for edible noncarcass tissues. Therefore, some US beef slaughter organizations have recommended a 48-h voluntary removal of ractopamine before slaughter in order to meet residue requirements of specific export countries and maintain international trade. Our objective was to assess the impact of voluntary removal of ractopamine hydrochloride (Optaflexx®; Elanco, Greenfield, IN) up to 8 d before slaughter on growth performance and carcass characteristics. Crossbred beef steers (60 pens of 10 animals/pen) with an initial shrunk body weight (BW) of 611.8 ± 10 kg SEM were fed one of six treatments over 42 d. Treatments included a control that did not receive ractopamine, on-label use of ractopamine (0-d withdrawal), and 2, 4, 6, or 8 d of voluntary removal of ractopamine from feed before slaughter. The start of ractopamine feeding (30.1 mg/kg of diet dry matter for 32 d) was staggered so that blocks could be slaughtered on the same day. Dry matter intake was decreased by 0.5 kg/d when ractopamine was fed with a 0-d withdrawal (P = 0.04) compared to the control, but was not altered (P = 0.56) as the duration of ractopamine removal increased from 0 to 8 d. Final BW, total BW gain, and average daily BW gain were increased by feeding ractopamine with a 0-d withdrawal (P = 0.09) compared to the control, but these variables decreased in a linear manner (P = 0.10) as the duration of removal increased from 0 to 8 d. Gain efficiency was improved by 15% (P < 0.01) by feeding ractopamine with a 0-d withdrawal compared to the control, and gain efficiency decreased linearly (P = 0.06) as the duration of ractopamine removal increased. Approximately 2/3 of the increase in gain efficiency remained after 8 d of removal. Hot carcass weight was increased by 6 kg (P = 0.02) by feeding ractopamine with a 0-d withdrawal compared to the control. Measured carcass characteristics were not altered by ractopamine feeding or by removal before slaughter (P ≥ 0.24). The consequences of voluntary removal of ractopamine up to 8 d before slaughter were a linear decrease in live BW gain (0.64 kg/d), poorer gain efficiency, and numerically lighter carcass weight.

Download Full-text

UTILIZATION OF GRASS SILAGE BY CATTLE: EFFECT OF BARLEY AND FISHMEAL SUPPLEMENTS

Canadian Journal of Animal Science ◽

10.4141/cjas85-105 ◽

1985 ◽

Vol 65 (4) ◽

pp. 897-903 ◽

Cited By ~ 12

Author(s):

D. M. VEIRA ◽

M. IVAN ◽

G. BUTLER ◽

J. G. PROULX

Keyword(s):

Formic Acid ◽

Nitrogen Content ◽

Dry Matter ◽

Dry Matter Intake ◽

Beef Steers ◽

Large Reduction ◽

High Nitrogen Content ◽

High Nitrogen ◽

Grass Silage ◽

Ad Libitum

Following weaning at 6–7 mo of age, 36 beef steers were used to determine production responses when grass silage was supplemented with barley or fishmeal. The silage was made from direct-cut, formic- acid-treated grass harvested from a mixed sward and had a high nitrogen content but poor fermentation characteristics. The silage was fed ad libitum for 98 days either alone or supplemented with 500 g fishmeal or 500 g barley per day. Both fishmeal and barley increased total dry matter intake (P < 0.01) by an amount equivalent to the quantity of supplement offered but had no effect on silage intake (P > 0.05). Steers fed the fishmeal grew substantially faster than either the barley (0.53 kg/day) or unsupplemented (0.54 kg/day) groups (P < 0.01). Fishmeal supplementation resulted in a large reduction (35%) in the amount of feed required per kilogram of gain. Key words: Cattle, grass silage, fishmeal, growth

Download Full-text

PSXII-18 The influence of molybdenum in drinking water or feed on apparent absorption and retention of molybdenum and copper in beef steers

Journal of Animal Science ◽

10.1093/jas/skz258.840 ◽

2019 ◽

Vol 97 (Supplement_3) ◽

pp. 423-424

Author(s):

Meghan P Thorndyke ◽

Nicole M Tillquist ◽

Nicole M Jones ◽

Terry Engle

Keyword(s):

Drinking Water ◽

Dry Matter ◽

Block Design ◽

Sodium Molybdate ◽

Mixed Effects ◽

Dry Matter Intake ◽

Beef Steers ◽

Apparent Absorption ◽

Randomized Block Design ◽

Intake Control

Abstract Twelve Angus steers (BW 694.1 ± 47.4 kg) fitted ruminal cannulae were used to examine the effect of molybdenum (Mo) supplemented in drinking water or feed on apparent absorption and retention of Mo and copper (Cu). Steers were fed a low-quality grass hay diet (DM basis: 6.5% CP; 0.13% S, 3.4 mg Cu/kg, 2.4 mg Mo/kg) for 14 d. Steers were then housed in individual metabolism stalls for 3 d to determine DMI. Steers were then blocked by BW and DMI and randomly assigned within block to one of three treatments (n = 4 steers per treatment). Treatments consisted of: 1) Control (no supplemental Mo); 2) 5.0 mg Mo/kg DM from sodium molybdate dihydrate (Mo-diet), and 3) 1.5 mg Mo/l from sodium molybdate dihydrate delivered in the drinking water (Mo-water). After the 3d DMI determination period, total fecal and urine output was collected for 5 d. Dry matter intake and DM digestibility were similar across treatments. Data were analyzed using a mixed effects model (PROC MIXED, SAS) for a completely randomized block design. Apparent absorption of Cu was greater (P < 0.05) in Control and Mo-water steers when compared to Mo-diet steers. Apparent retention of Cu was greater (P < 0.05) in Control steers when compared to Mo-diet steers. Steers receiving Mo-water had a similar apparent retention of Cu when compared to Control and Mo-diet steers. By design, treatment was a significant (P < 0.01) source of variation for Mo intake. Control steers had lesser (P < 0.05) Mo intake when compared to Mo-diet and Mo-water supplemented steers. Apparent absorption and retention of Mo were greater (P < 0.05) in Mo-diet steers compared to Control and Mo-water steers. These data indicate that Mo metabolism and apparent absorption of Cu are different when Mo is supplemented in water relative to feed.

Download Full-text

Effect of Forage:Concentrate Ratios in the diet and Intake Restriction on the Rumen Fermentation and Hormone Profiles of Finishing Beef Steers.

Proceedings of the British Society of Animal Production (1972) ◽

10.1017/s0308229600026167 ◽

1994 ◽

Vol 1994 ◽

pp. 69-69

Author(s):

C.L. Thorp ◽

R.W.J. Steen ◽

A.R.G. Wylie ◽

J.D. McEvoy ◽

C. Shaw

Keyword(s):

Growth Factor ◽

Beef Cattle ◽

Energy Intake ◽

Dry Matter ◽

Rumen Fermentation ◽

Fat Content ◽

Carcass Composition ◽

Dry Matter Intake ◽

Beef Steers ◽

Reducing Energy

Studies have shown that reducing energy intake by restricting dry matter intake (DMI) at a constant forage: concentrate (F:C) ratio is more effective at increasing carcass lean and reducing carcass fat content than is reducing energy intake by increasing the F:C ratio (1). Research at this Institute has also shown that, per megajoule of digestible energy (DE), diets restricted in this manner are 45 % more efficient at producing carcass lean.The mechanism by which these methods of restriction result in these differences in carcass composition has previously been assumed to be that of rumen fermentation. More recently however, the significance of rumen fermentation in controlling the carcass composition of beef cattle has been questioned (2,3).The aim of this experiment was to examine the effect of decreasing the F:C ratio, at constant DE and DMI, on both rumen and endocrinological parameters, in particular the hormones insulin and insulin like growth factor-1 (IGF-1), in finishing beef steers.

Download Full-text

Herbage characteristics of perennial ryegrass, cocksfoot, tall fescue and timothy pastures and their relationship with animal performance under upland conditions

The Journal of Agricultural Science ◽

10.1017/s0021859600055155 ◽

1982 ◽

Vol 99 (1) ◽

pp. 153-161 ◽

Cited By ~ 16

Author(s):

D. A. Davies ◽

T. E. H. Morgan

Keyword(s):

Perennial Ryegrass ◽

Tall Fescue ◽

Growth Rates ◽

Dry Matter ◽

Live Weight ◽

Phleum Pratense ◽

Water Soluble ◽

The Other ◽

Dry Matter Intake ◽

Grass Species

SUMMARYHerbage characteristics of perennial ryegrass (Lolium perenne L.), cocksfoot (Dactylis glomerata L.), tall fescue (Festuca arundinacea Schreb.) and timothy (Phleum pratense L.) pastures were obtained whilst rotationally grazed by ewes and their single lambs at a fixed stocking rate of 25/ha on an upland site (305 m O.D.) in mid-Wales. Drymatter production of cocksfoot averaged 32·1 kg/ha/day over the 3-year duration of the trial (1975·7) and was 13·3 kg/ha/day lower than that of the other three grass species. This resulted in a 8 kg/ha/day reduction in dry-matter intake on cocksfoot; this was significantly lower (P < 0·05) than that achieved on the other grasses, which were similar to one another around 36 kg/ha/day.In vitro digestibility of the herbage ranked in the order perennial ryegrass > timothy = cocksfoot > tall fescue. Intake of digestible organic matter (DOMI) was lower on cocksfoot than on perennial ryegrass and timothy. Differences were also detected in crude protein, water-soluble carbohydrates and sodium composition between species.Dry-matter intake was positively correlated with herbage growth rates (r = 0·95, P < 0·001) but not to digestibility of herbage on offer (r = 0·18). Both ewe and lamb live-weight gains were positively related to intake of dry matter and DOMI.Reference is made to comparative yield data between the grasses obtained under cutting trials. In the 2nd and 3rd harvest years (1967–1967) growth rates in the grazing experiment were 76, 61, 81 and 80% of the 66·2, 66·7, 67·8 and 65·0 kg D.M./ha/day obtained under a cutting regime on perennial ryegrass, cocksfoot, tall fescue and timothy swards respectively. This illustrates the danger involved in assessing the potential of grasses based on such information.The results are discussed in relation to the value of the species for use under grazing in the uplands.

Download Full-text