Proceedings, Western Section, American Society of Animal Science

Vol.50, 1999

FEEDING VALUE OF TWO LEWIS X BARONESSE RECOMBINANT INBRED

BARLEY LINES, LB13 AND LB30,FOR FINISHING STEERS^[1]

D. L. Boss*²,J.G.P. Bowman³,L.M.M. Surber³, D. C. Anderson², and T. K. Blake³

²Northern Agricultural Research Center, Havre, MT 59501

³Montana State University, Bozeman, MT 59717

Introduction

In the Pacific Northwest and Canada barley is the predominant grain in feedlot diets.At this time there is no established criteria to determine the feeding value of different barley varieties.However, differences have been shown to exist between barley varieties in finishing performance of steers (Ovenell et. al., 1993; Boss and Bowman, 1996;Surber et al., 1998).

The objectives of this study were to evaluate feedlot performance and carcass characteristics of two recombinant inbred barley lines (RILs) developed from a Lewis x Baronesse cross.

Materials and Methods

Eighty crossbred steers (avg wt 349 kg) were allotted to 16 pens in a completely randomized design on an equal pen weight basis to measure feedlot performance and carcass characteristics of two RILs developed from a Lewis x Baronesse cross.During Period 1 (70 d) steers were fed 85% barley diets based on either Baronesse (BAR; a two row feed variety), or Lewis (LEW; a two-row malt variety).During Period 2 (79 d) steers were fed 85% barley diets based on one of four barleys: 1) BAR, 2) LEW, 3) LB13, or 4) LB30.Composition of the barley varieties and four dietary treatments are given in Tables 1 and 2.LB 13 and LB 30 (RILs developed from Lewis and Baronesse crosses) were selected based on positive agronomic performance, particle size when dry rolled and in situ DMD. 

Barley varieties were grown under dryland conditions near Havre, MT.All diets were balanced to be isocaloric (1.39 Mcal NE_g/kg), isonitrogenous (2.25% N) and to meet or exceed NRC (1984) requirements for Ca and P, and other nutrients.Barleys were coarsely cracked prior to feeding.Wheat straw was chopped to pass a 5-cm screen before addition to the diet.Composition of the diets is presented in Table 2.Steers were implanted with Synovex7 Plus (trenbolone acetate and estradiol benzoate, Fort Dodge Laboratories, Fort Dodge, IA) after the initial 28 d on the feeding trial.Steers were weighed every 28 d throughout the trial.Initial and final weights were based on two consecutive days (unshrunk weights).

Feed samples were analyzed for DM, CP (AOAC, 1997), ADF (Van Soest et al., 1991) and starch (AOAC, 1997).Steers were allowed ad libitum access to water and were fed once daily approximately at 1000.Feed bunks were inspected prior to feeding and the amount of feed offered was adjusted daily.All orts were removed and weighed at least bimonthly.

Steers were slaughtered when 70% were visually estimated to grade Choice (E. A. Miller, Inc., Hyrum Utah).Hot carcass weight was recorded at slaughter.All other carcass traits were taken after a 24-h chill.Marbling and quality grade were assigned by a USDA grader.

Data were analyzed by the GLM procedure of SAS (1993).Planned comparisons of LB13 vs LEW and BAR and LB30 vs LEW and BAR were used for Period 2 data (offspring vs mean of parents).Treatment least square means were separated by the LSD method (SAS, 1993) if the treatment F-test was significant (P < .10).

Results and Discussion

During Period 1, no differences (P > .10) were found in ADG (avg 1.1 kg/d) or final weight (avg 427 kg) between steers fed BAR or LEW (Table 3).In addition, after Period 2 no differences (P > .10) were found in ADG (avg 1.58 kg/d) or final weight (avg 551 kg) between steers fed BAR or LEW.Steers fed LB13 and LB30 exhibited an 8.6 and 10% increase (P < .04) in ADG, respectively, compared with the parent varieties (1.72 and 1.74 kg/d, respectively, vs avg 1.58 kg/d).No differences (P > .10) were detected in DMI (avg 9.4 kg/d).Gain/feed was higher (P < .10) for steers fed LB30 (18.2 kg/100 kg) compared with those fed the parent varieties (17.2 kg/100 kg).These results agree with Blackhurst et al. (1999) in that RILs from Lewis x Baronesse crosses do perform differently than their parent varieties in finishing diets.

Diet did not affect (P > .10) carcass wt (avg 311 kg), marbling score (avg 3.7, slight 70), Quality grade (avg 11.3, select),%KPH (avg 2.1%), longissimus muscle area (avg 79.2 cm²) or yield grade (avg 2.3;Table 4).These results agree with Ovenell et al. (1993) and Surber et al. (1998) who reported that carcass traits have not been affected by barley variety.In contrast, quality grade has at times been reported to be affected by barley variety (Boss and Bowman, 1996; Blackhurst et al., 1999).

Implications

LB30 had improved ADG and an improved feed efficiency when compared to its parent varieties.Due to improved feeding value compared to the parent varieties, Lewis and Baronesse, LB 30 has been released as an improved feed quality barley, named AValier@.

Literature Cited

AOAC.1997.Official Methods of Analysis of AOAC International (16^th. Ed.)AOAC International, Gaithersberg, MD.

Boss, D. L., and J.G.P. Bowman.1996.Barley varieties for finishing steers: I. Feedlot performance, in vivo diet digestion, and carcass characteristics.J.Anim. Sci 74:1967-1972. 

Blackhurst, T. C., J.G.P. Bowman, L.M.M. Surber, T. J. Milner, T. K. Daniels, and T. K. Blake.1999.Feeding value of Lewis x Baronesse recombinant inbred lines for finishing steers.Proc.West.Sect.Am.Soc.Anim. Sci. 50 (In press)

NRC.1984.Nutrient Requirements of Beef Cattle (6^th Ed.) National Academy Press, Washington, DC.

Ovenell, K. H., M. L. Nelson, J. A. Froseth, S. M. Parish, and E. L. Martin.1993.Feedlot performance, carcass characteristics of steers, and digestibility of diets containing different barley cultivars.Proc.West.Sect.Am.Soc.Anim. Sci. 44:416-419.

SAS.1993.SAS/STAT User Guide. SAS Inst. Inc. Cary, NC.

Surber, L.M.M., J.G.P. Bowman, T. K.Daniels, T. J. Milner,A. L. Lewis, D. M.Coulson, and T. K. Blake.1998.Feeding value of barley varieties for finishing cattle.Proc.West.Sect.Am.Soc.Anim. Sci. 49:268-271.

Van Soest, P. J., J. B. Robertson, and B. A. Lewis.1991.Methods for dietary fiber, neutral detergent fiber, and nonstarch polysaccharides in relation to animal nutrition.J Dairy Sci.74:2866.

Table 1.Composition of Baronesse, Lewis, LB13 and LB30 barley grain (DM basis).
 

Item	Baronesse	Lewis	LB13	LB30
DM, %	89.6	89.1	89.5	89.4
CP, %	15.6	15.6	13.6	14.6
ADF, %	5.6	4.1	5.0	4.6
Starch, %	54.7	56.9	58.5	60.0

 
   

Table 2.Composition of finishing diets based on Baronesse, Lewis, LB13 and LB30 barley varieties (DM basis).

 

Item

BAR

LEW

LB13

LB30

Ingredients

Cracked Barley	85.99	85.99	85.99	85.99
Chopped wheat straw	6.00	6.00	6.00	6.00
Corn Oil	3.00	3.00	6.00	6.00

Sodium bicarbonate

1.30

1.30

1.30

1.30

Potasium chloride

.5

.5

.5

.5

TM premix a

.25

.25

.25

.25

Urea, 45%

.10

.10

.70

.40

Vit A, D, E premix b

.05

.05

.05

.05

Rumensin c, 60 g/lb

.024

.024

.024

.025

Tylan, 40 g/lb

.013

.013

.013

.013

Microgrits, color

.011

.011

.011

.011

Chemical composition

DM, %

91.1

90.8

91.5

90.3

N, %

2.16

2.28

2.19

2.29

ADF, %

7.54

7.75

7.94

8.20

Starch, %

43.3

46.1

45.7

41.3

 

 

^[1]The authors gratefully acknowledge the USDA Special Grant, Barley Feed for Rangeland Cattle, for financial support of this research.