C O N T E N T S

Cowherds and Reproduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Survey of Kansas Cow-Calf Producers 1

. . . . . . . . . . . . . . . . . . . . . . . Incidence o f Short Estrous Cycles After Weaning in Beef Cows. 6

Ef fec ts from Using Ralgro Sequen t ia l l y on Sexual Development o f B u l l s and on Growth and Carcass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Charac te r i s t i cs o f Steers and B u l l s . 8

. . . . . . . . . . . . . E f f e c t o f Growth Rate from B i r t h Through T h i r t y Months on Performance of Hei fers . 11

Pe lv i c Area, Ca lv ing Ease and Rebreeding i n F i r s t Cal f He i fe rs

Delayed Winter Supplemental Feeding and Year-round Mineral Supplementation o f Beef Cows on Native Range . . 17

Effects o f Ralgro and DES Implants During the Suck l ing Per iod on Later . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Reproduct ive Pe r fo rmance o f Beef He i fe rs 19

. . . . . . . . . . . . . . . . . . . . . . . . . . . . Evaluat ing the Breeding Po ten t i a l o f Year l ing Bulls 22

Forages and Pastures

. . . . . . . . . . . . . . . . . . . Minera ls in Esophageal Samples f r o m Steers on Nat ive Bluestem Pastures. 25

M i l o Stover, Forage Sorghum, P r a i r i e Hay, Soybean Meal and Urea Compared f o r Growing Hei fers . 28

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Using Wheat S t r a w i n Beef Cow Rations 32

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Y i e l d and Quality o f S i x Summer Annual Forages 35

Feedl ot Studies

. . . . . . . . . . . . . . . . . . . . . . . Pro te in Leve ls With and Without Monensin f o r F in i sh ing Steers 39

P r e d i c t i n g Feedlot Performance Using Mathematical Models 44

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pro te in Adjustments During Temperature St ress 48

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . High Moisture Corn f o r F i n i s h i n g Steers 51

Conventional versus Accelerated Beef Production fo r T r a d i t i o n a l and Later- matur ing C a t t l e Types 55

Performance, Carcass, and Meat T r a i t s of D i f f e r e n t C a t t l e Types 58

Meats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Processing Re ta i l Beef Cuts f rom Boxed Beef 63

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N u t r i t i o n a l Effects on Beef P a l a t a b i l i t y . 65

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mechanical Blade Tenderization o f Meat. 68

Rumen Physiology

Rumen B a c t e r i a l Endotoxins and Thei r Possible Role i n t h e Sudden-death Syndrome 71

. . . . . . . . . . . . . . . . . . . . . . Ef fec ts o f Rumensin or Lasa loc id on Rumen Fermentat ion i n V i t r o 73

B i o l o g i c a l Variability and Chances o f Error The variability among individual animals in an experiment leads t o problems i n i n t e r p r e t i n g

the results. Although the c a t t l e on treatment X may have had a larger average da i l y ga in than those on treatment Y , v a r i a b i l i t y w i t h i n t r e a t m e n t s may mean t h a t the d i f f e r e n c e w a s no t t he r e s u l t o f the t reatment alone. S t a t i s t i c a l ana l ys i s l e t s researchers c a l c u l a t e the p r o b a b i l i t y t h a t such d i f f e rences were f rom chance r a t h e r than treatment.

In some of the articles t h a t f o l l ow , you will see the notation "P<.05." That means the p r o b a b i l i t y o f the d i f fe rence r e s u l t i n g from chance i s l e s s than 5%. If t w o averages a re said t o be " s i g n i f i c a n t l y different," the p r o b a b i l i t y i s l e s s than a 5% t h a t the d i f fe rence i s f rom chance--the p r o b a b i l i t y exceeds 95% t h a t the d i f f e r e n c e r e s u l t s f r o m t h e t reatment.

I n other cases you may see a mean g iven as 2.50 + 0.10. The 2.50 i s t h e m e a n ; 0.10 is the "standard e r r o r . " Two-thirds of the I n d i v i d u a l v a l u e s w i l l f a l l w i t h i n one standard error from the mean. I n this case between 2.40 and 2.60 (2.50 - 0.10 and 2.50 + 0.10).

Many animals per treatment, r e p l i c a t i n g t r e a t m e n t s several t imes, and using uni form animals increases the p r o b a b i l i t y t h a t observed d i f f e rences r e s u l t f r o m t reatments , n o t chance.

In n e a r l y a l l t h e research reported here, statistical analyses are included t o Increase t h e conf idence you can p lace in the resu l t s .

28

1 Milo Stover, Forage Sorghum, Prairie Hay,Soybean Meal and Urea Compared for Growing Heifers

Keith Bolsen, Jim Oltjen and Harvey Ilg

Summary

Milo stover silage, prairie hay or forage sorghum silage was fed inrations containing 10, 12 or 14% protein from soybean meal (SBM) or 12%protein from urea; 100 heifers were fed in the 78-day growing trial (November11, 1977 to February 2, 1978).

Heifers fed forage sorghum silage, prairie hay or forage sorghum silage+ prairie hay had similar rate and efficiency of gains; those fed milo stoversilage made slowest and least efficient gains. Rations containing prairiehay were consumed in the greatest amounts. Feeding rations with 12 or 14%protein from SBM gave better performance than rations with 10% protein fromSBM. Heifers fed urea gained slower and less efficiently than those fed SBM.Gain from a ration containing equal parts of milo stover silage and foragesorghum silage exceeded predicted gain by 7.8%, and efficiency was 13.9%bet ter than predic ted .

Introduction

Milo stover and forage sorghum silages were compared in five previousheifer growing trials at this station (Prog. Rpt. 210, 230, 262, 291 and 320,Kansas Agr. Expt. Sta.). Results show: (1) growing calves fed milo stoversilage should gain about 1.0 lb. per day and require 10 to 14 lbs. of drymatter per lb . of gain , (2) milo stover silage has a feeding value of 65% ofthat of forage sorghum silage, (3) milo stover silage fed in combination withforage sorghum silage is better feed than milo stover alone for growing calves,(4) supplying supplemental protein in milo stover silage rations is a large costbecause stover usually contains so lit t le protein, and (5) at least 12% proteinrations are needed for maximum rate and efficiency of gain.

This trial was to verify previous results from feeding milo stover andforage sorghum silages, to evaluate prairie hay and to compare three levelsof supplemental protein from soybean meal and one from urea.

29

Experimental Procedure

Shown below are the forage and protein rations compared in a 78-daygrowing trial (November 11, 1977 to February 2, 1978).

Forages

Milo stover silage (MSS)Prairie hay (PH)Forage sorghum silage (FSS)½ MSS + ½ FSS½ PH + ½ FSS

Protein, %of the ra t ion

from (SBM)

10, 12 and 1410, 12 and 1410, 12 and 1410, 12 and 1410, 12 and 14

Protein, %of the ra t ion

from urea

1212121212

The 100 heifer calves averaged 430 lbs. when allotted by breed and weightinto 20 pens of five each. Breeds included Angus, Hereford, Angus x Herefordand Hereford x Simmental. Four pens were assigned to each of the 5 foragetreatments. All rations were 73% of the appropriate forage and 27% rolledmilo plus protein supplement on a dry matter basis and formulated to be equalin minerals, vitamins and additives. All were mixed and fed to appetite twiceda i ly .

All calves were fed 2 lbs. of rolled milo and alfalfa hay free-choice for5 days before initial weighing and all were fed the same amount of experimentalration for 2 days before final weighing. All feed and water were withheld 16hours before weights were taken.

Forage sorghum was a high-grain variety harvested in the dough-stage at70 to 72% moisture. Milo stover was from dryland milo that had been harvestedabout 30 days before stover was harvested. The stover was about 70% moisturewhen the grain was harvested. The forage sorghum and milo stover silages weres tored in concrete s i los (10 f t . x 50 f t . ) . The native prairie hay was swathedand field-dried before being baled into rectangular bales about 75 to 80 lbs.each, and later processed in a tub grinder before being fed.

Results

Dry matter (%), crude protein (%, DM basis) and crude fiber (%, DM basis),respect ively, for the three forages were: 28.0, 8.0, 31.0 for milo stoversilage; 88.0, 5.5, 32.6 for prairie hay; and 28.5, 8.9, 26.3 for forage sorghums i l age .

There were no interactions between forage and protein. Performances ofheifers fed each of the five forages (averaged across protein treatments) areshown in Table 10.1; performances of heifers fed each of the four proteintreatments (averaged across forages), in Table 10.2.

Heifers fed forage sorghum silage, prairie hay or FSS + PH had similarrates of gain. Feed intake was higher (P‹.05) for prairie hay and PH + FSSthan for forage sorghum silage. Milo stover silage supported the slowest(P‹ .05) and least eff ic ient (P‹ .05) gains .

30

The 12 and 14% protein rations from SBM supported the fastest and mostefficient gains (P<.05)(Table 10.2). Calves fed the 10% protein ration fromSBM gained faster and more efficiency (P‹.05) than calves fed the 12% proteinration from urea. In general, performance of faster gaining calves (those fedforage sorghum silage, prairie hay or FSS + PH) tended to be improved morewith additional SBM protein than that of calves gaining slower (those fedmilo s tover s i lage) .

From these results feed costs and feed cost per lb. of gain can becalculated for each combination of forage and protein. When the price ofSBM is high compared with that of urea and grain, the economic advantage offeeding 12 or 14% protein rations from SBM, of course, would be less than whenSBM prices are low.

We used gains and feed efficiencies from the milo stover silage andforage sorghum silage rations to calculate predicted gain and efficiencyfor the 50% MSS + 50% FSS ration (Table 10.3). Observed gain exceeded predictedgain 0.08 lb. per day or 7.8%, and observed feed efficiency exceeded predictedefficiency 1.86 lbs. of feed per lb. of gain or 13.9%. The value of milo stoversilage in growing rations for calves,forage sorghum silage.

therefore, is improved by feeding it with

Table 10.1. Performances of heifers fed the five forages.

Item FSS 1Forage

MSS 1 PH 1 MSS + FSS PH + FSS

No. of calvesI n i t i a l w t . , l b s .

20 20 20429 427 429

20 20429 429

Avg. dai ly gain, lbs . 1.25 a .79c 1.22a l . l 0b 1.32a

Avg. dai ly feed, lbs .2 13.03b 11.84 c 15.03 a 12.43 b 14.26a

Feed/ lb . of gain , lbs . 2 10.59a 16.18 c 12.40b 11.52 b 11.58 b

1 FSS2

= forage sorghum silage; MSS = milo stover silage; PH = prairie hay.

100% dry matter basis.a,b,c Means in the same row with different superscripts differ significantly

(P‹ .05) .

31

Table 10.2. Performances of heifers fed the four protein treatments.

Item

Prote in t rea tment : source and levelSBM Urea

10% 12% 14% 12%

No. of calves 25 25 25 25I n i t i a l w t . , l b s . 429 428 427 429

Avg. dai ly gain, lbs . l . l 0b 1.22a 1.28a

.94 c

Avg. daily feed, lbs. 1 13.39 13.55 13.45 12.90

Feed/ lb . of gain , 1bs .l 12.83b 11.33a 10.67a 15.00c

1 100% dry matter basis.a,b,c Means in the same row with different superscripts differ significantly

(P‹ .05) .

Table 10.3. Observed and predicted rates and efficiencies of gain byheifers fed milo stover silage, milo stover silage + foragesorghum silage, or forage sorghum silage.

Item MSSForage

FSS + MSS FSS

No. of calves

Avg. daily gain, lbs.ObservedPredictedImprovement, lb.1

Improvement, %

Feed/ lb . of gain , lbs .ObservedPredictedImprovement, 1bs.l

Improvement, %

20 20 20

.79 1.10 1.25- - - 1.02 - - -

+.08+7.8

16.18 11.52 10.59- - - 13.38 - - -

-1.86+13.9

1 Observed minus predicted.

35

Yield and Quality of Six Summer Annual Forages

Mopoi Nuwanyakpa, Gerry L. Posler,Keith K. Bolsen, and Harvey Ilg

Summary

In 1977, all summer annual forages studied produced excellent yields.Based on leafiness and regrowth ability, sudangrasses and pearl millet appearedto be best for early vegetative and boot cutting management. The sorghum-sudan hybrids had suitable yields and quality at all harvest stages. Thehybrid forage sorghum appeared best suited for soft-dough-stage harvestalthough yields of pearl millet and sorghum-Sudan hybrids were also excellent.

Many summer annual crops can provide excellent forage during the hot,dry summers in Kansas when other pasture grasses have declined in productionand quality. Summer annuals, including sudangrasses, hybrid sudangrasses,sorghum-sudangrass hybrids, sorgos, hybrid forage sorghums, and pearl millets,may be used for pasture, hay, silage, and greenchopping. Differences intheir anatomy and growth characteristics reward producers who carefullyselect the proper crop to match their l ivestock needs.

Introduction

In 1977 at Manhattan and Hutchinson, we evaluated forage yield andquality of six forages, harvested at early vegetative, boot, and soft-doughstages of growth. Forages tested were 'Piper' sudangrass, Northrup King'Trudan 6' hybrid sudangrass, Dekalb 'Sudax SX-11', and Ring Around 'SuperChow Maker 235' sorghum-sudangrass hybrids, Dekalb 'FS 25a' hybrid foragesorghum, and Northrup King 'Millex 23' hybrid pearl millet.

Materials and Methods

The hybrid forage sorghum was planted in 30-inch rows; all others,in 6-inch rows. Plots were 5 x 20 feet for the narrow spacing and 10 x 20feet for the wide spacing. The center 3 feet or 2 rows were harvested foryield, leaving a 6-inch stubble. Harvests were by stage of growth, notcalendar date. At Hutchinson, forages were cut 3 times at the early vegetativestage, 2 times at the boot stage, and 1 time at the dough stage. One additionalearly vegetative cutting was obtained at Manhattan. Samples were takenfrom the flail-chopped material for dry matter and quality analyses.

Experimental Results

36

As shown in Tables 12.1 and 12.2, mean forage yields were similar atHutchinson and Manhattan for the early vegetative stage, greater at Hutchinsonfor the boot stage, and greater at Manhattan for the soft-dough stage.The forages sometimes responded differently at the two locations. The mostdifference was noted for Millex at the soft dough stage; it yielded muchbetter at Manhattan. Cut t ings were a t d i f ferent calendar dates , and ra infal lpat terns d i f fered between locat ions , but such differences are expected andwould be expected in other years.

Crude protein content and in vitro digestible dry matter (IVDDM) declinedwith advancing maturity. Crude protein was always lower at Hutchinson,par t icular ly a t the sof t dough s tage, probably par t ly because of near-recordAugust ra infal l , unusual ly high yie lds , and moderate ni t rogen fer t i l iza t ion.

Piper sudangrass and Trudan hybrid sudangrass performed best for earlyvegetative and boot harvests. The FS 25A hybrid forage sorghum, as expected,performed poorly under early vegetative management, and its yield was quitelow at the boot stage at Manhattan. At Hutchinson, it yielded well despitebeing cut only once, while the others were cut twice. Yields of the twosorghum-sudan hybrids and pearl millet varied most at the various stagesand locations. Additional years of data are needed to better estimate thefo rages ' t r ue y i e ld ing ab i l i t i e s .

Summer annual forages vary in growth characteristics.

10.319.2

3 7

Table 12.1. Forage yields and quality of six summer annual forages cut atthree stages of growth, Manhattan.

Crudeprotein

%IVDDM

a

%

Forage yie ld ( ton/acre)Dry matter 60% H2 0Forage

Early vegetat ive s tage

PiperTrudan-6S.C. Maker 235Sudax SX-11Millex 23FS 25A 8 . 4

Mean

5 . 0 14.3 19.24.9 14.0 17.85.1 14.7 19.25.4 15.5 20.16.1 17.5 21.5

14.12.94.9

19.719.6

67.367.666.165.167.465.666.5

Boot stage

PiperTrudan 6 6 . 3S.C. Maker 235Sudax SX-11Millex 23FS 25A

Mean

6.5

8.26.97.45.06.7

18.718.023.419.621.2

14.3 63.115.6 61.814.5 62.612.6 61.016.6 63.912.5 58.614.4 62.6

Soft dough stage

7.6 21.7 10.2 49.88.4 24.0 8.9 51.5

16.6 47.3 8.3 50.99.1 50.3

13.426.0 9.938.2 10.2 52.8

12.2 34.8 8.732.0 9.4

53.111.2 51.4

PiperTrudan 6S.C. Maker 235Sudax SX-11Millex 23FS 25A

Mean

LSD.05 2.3 4.8 1.2 2.5

a IVDDM = In vitro digestible dry matter.

Early vegetative stage

38

Table 12.2. Forage yields and qualities of six summer annual forages cut atthree stages of growth, Hutchinson.

Forage yield (ton/acre)Dry matter 60% H2 0

Crudeprotein

%IVDDM a

%Forage

Piper 5.1 14.5Trudan 6S.C. Maker 235Sudax SX-11 5 . 8 16.7Millex 23FS 25A

Mean3.9

5.7

11.4

16.45.8

5.1

16.7

4.4

14.7

12.6

13.8 66.214.3

17.3

67.2

64.6

13.8 67.414.9

14.8

66.6

67.1

14.8 70.8

9.1 59.88 . 3 8.5 62.9

8.3 62.310.3 61.011.1 65.8

7.8 22.2

10.023.6

12.428.735.3

7.0 20.09.9 28.49.2 26.4

Boot stage

PiperTrudan 6S.C. Maker 235Sudax SX-11Millex 23FS 25A

M e a n

Soft dough stage

7.89.2

58.361.7

6 . 6 50.96 . 0 51.33.3 53.95.7 56.33.9 55.3

12.0 4.0 58.610.1 4.9 54.4

5.4 15.58.1 23.1

15.7 44.711.0 31.08.4 23.9

34.228.3

PiperTrudan 6S. C. Maker 235Sudax SX-11Millex 23FS 25A

Mean

LSD .05 1.6 3.7 1.7 2.4

a IVDDM= In vi t ro digest ible dry mat ter .

ACKNOWLEDGMENTS

T h e D e p a r t m e n t of Animal S c i e n c e s a n d I n d u s t r y s i n c e r e l y t h a n k s t h e f o l l o w i n g i n d i v i d u a l s a n d c o m p a n i e s for s u p p o r t t h r o u g h r e s e a r c h g r a n t s , p r o d u c t s , or s e r v i c e s . T h e i r h e l p h a s a d d e d much t o o u r r e s e a r c h effort .

A b b o t t L a b o r a t o r i e s

C. K. Al l e n , Woodland Farms

Amer ican Cyanamid Company

Cadco Company

C h i c a g o , I l l i n o i s

S a v a n n a h , M i s s o u r i

P r i n c e t o n , New Jersey

D e s M o i n e s . Iowa

Cel a n e s e Chemica l Company C o r p u s C h r i s t i . T e x a s

Bi ll y C l a r k . C l a r k H e r e f o r d s B a r n a r d , K a n s a s

F l o y d Coen El k h a r t , K a n s a s

Cry-O-Vac D i v i s i o n , W. R . Grace Duncan, S o u t h C a r o l i n a

Dugdal e P a c k i ng Company

Dow Chemica l Company

E l a n c o P r o d u c t s Company D i v i s i o n of E l i L i l l y

F o u r t h N a t i o n a l Bank

Hess a n d C l a r k Company

Roman L. H r u s k a U.S. Meat Animal R e s e a r c h C e n t e r

IMC Chemica l Group I n c .

S t . J o s e p h , M i s s o u r i

Midl a n d , M i c h i g a n

I n d i a n a p o l i s, I n d i a n a

W i c h i t a , K a n s a s

A s h l a n d , O h i o

N u t l e y , New Jersey

C l a y C e n t e r , N e b r a s k a

T e r r e H a u t e , I n d i a n a

I n t e r n a t i o n a l S t o c k Food. I n c . Waverly. New York

Kemin I n d u s t r i e s , I n c . D e s M o i n e s , Iowa

Lilll y R e s e a r c h L a b o r a t o r i e s D i v i s i o n of E l i L i l l y

L i v e s t o c k & M e a t I n d u s t r y C o u n c i l , I n c . (LMIC)

M a n h a t t a n L i v e s t o c k Exchange

Merck & Company. I n c .

R o s s I n d u s t r i e s I n c .

G. D. S e a r l e Company

G r e e n f i e l d , I n d i a n a

M a n h a t t a n , K a n s a s

M a n h a t t a n , K a n s a s

Rahway, New J e r s e y

M i d l a n d , V i r g i n i a

E l b u r n , Illinois

T h e i s P a c k i n g Company Great Bend , K a n s a s

Thompson-Hayward Chemica l Co.

Union C a r b i d e

The UpJohn Company

K a n s a s C i t y , K a n s a s

C h i c a g o . Ill1 i n o i s

Kal amazoo, M i c h i g a n

U n i v e r s i t y o f N e b r a s k a L i n c o l n , N e b r a s k a

USS A g r i - Chemical s Atlanta, G e o r g i a

Company a n d b r a n d names a r e u s e d o n l y f o r easier c o m m u n i c a t i o n . They i m p l y n o p r e f e r e n c e o r e n d o r s e m e n t .