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Group Title: Research report - North Florida Research and Education Center ; 88-11
Title: Beef Production in relation to creep feeding, zeranol implants and breed type II. weanling heifer development and compostion
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Title: Beef Production in relation to creep feeding, zeranol implants and breed type II. weanling heifer development and compostion
Series Title: Research report (North Florida Research and Education Center (Quincy, Fla.))
Physical Description: 26 leaves : ill. ; 28 cm.
Language: English
Creator: Prichard, D. L
North Florida Research and Education Center (Quincy, Fla.)
Publisher: North Florida Experiment Station
Place of Publication: Quincy Fla
Publication Date: 1988
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Subject: Beef cattle -- Reproduction   ( lcsh )
Beef cattle -- Feeding and feeds -- Florida   ( lcsh )
Genre: bibliography   ( marcgt )
non-fiction   ( marcgt )
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Bibliography: Includes bibliographical references (p. 14-16).
Statement of Responsibility: by D.L. Prichard, T.T. Marshall, D.D. Hargrove, and T.A. Olson.
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BEEF PRODUCTION IN RELATION TO CREEP FEEDING, ZERANOL

IMPLANTS AND BREED TYPE: II. WEANLING HEIFER DEVELOPMENT

AND COMPOSITION



D. L. Prichard*, T. T. Marshall, D. D. Hargrove,

and T. A. Olson



University of Florida,

Gainesville 32611


























D. L. Prichard* T. T. Marshall, D. D. Hargrove, and T. A. Olson, North

Florida Research and Education Center, Route 3 Box 4370, Quincy, FL

32351. Contribution from the Animal Science Department, Inst. of Food

and Agric. Sci., Florida Stn., Univ. of Florida. Research Report 88-11.

*Corresponding author.










Abstract

Effects of preweaning creep feeding and zeranol implants on repro-

ductive tract development, udder and subcutaneous fat deposition, and

carcass composition were studied in 24 weanling heifers sired by Brahman

and Romana Red bulls and out of Angus and Angus x Brown Swiss F1

reciprocal crossbred cows. Creep treatment did not affect (P>.19)

ovarian weight, ovarian size, uterine horn diameter nor follicle number.

Heifers from the three creep treatments did not differ (P>.25) in udder

weight, total lipid or percent lipid in the udder. The noncreep-fed

(NC) heifers had a greater (P<.02) number of adipocytes per g of udder

tissue than did the long-term creep fed (LC) and short-term creep-fed

(SC) heifers. The LC heifers had significantly larger udder (166.0 vs

152.7 m) and subcutaneous adipocytes (166.7 vs 148.8 m) than NC

heifers. LC heifers had heavier (P<.10) empty body and hot carcass

weights than SC and NC heifers. Carcasses from LC heifers had more

(P<.04) separable fat, less (P<.11) separable lean and less (P<.05)

edible protein than carcasses from SC and NC heifers. Heifers implanted

with zeranol had a greater (P<.03) uterine horn diameter and heavier

(P<.02) uterine weight than non-implanted heifers. Percent lipid in the

udder was lower (P<.02) in heifers implanted with zeranol. Total udder

adipocytes did not differ (P>.22) between implanted and non-implanted

heifers; however, implanted heifers had smaller (P<.10) subcutaneous

adipocytes than non-implanted heifers. Implanted heifers had higher

(P<.02) cutability carcasses (lower yield grade number) than non-

implanted heifers. Zeranol implants increased carcass lean color

(P<.05) and maturity (P<.006). Zeranol decreased (P<.09) percent

separable fat and increased (P<.008) separable lean in the carcass.










Breed of dam did not affect (P>.17) development of the reproductive

tract of weanling heifers. Heifers from Angus dams had smaller (P<.08)

udders and less (P<.10) total fat in the udder than those from Fl dams,

and the heifers from Fl dams tended (P<.12) to have larger udder

adipocytes. Estimated separable and edible carcass components were not

affected (P>.19) by breed of dam. Brahman-sired heifers had a greater

ovarian weight (P<.04) and size (P<.02) than Romana Red-sired heifers.

Brahman-sired heifers had more (P<.004) total udder adipocytes;whereas,

Romana Red-sired heifers tended (P<.14) to have larger udder adipocytes.

Breed of sire did not affect (P>.18) estimated carcass composition or

USDA quality and yield grade traits.

(Key Words: Creep, Zeranol, Brahman, Romana Red, Reproductive tract,

Adipocytes, Carcass composition)

Introduction

The effects of creep feeding and preweaning growth stimulants on

future reproductive performance and maternal ability of replacement

heifers are of concern to many cattlemen. Most commercial cattlemen

sell some of their weaned heifers as feeder-stocker calves. By using

creep feed and growth stimulants, cattlemen can sell these heifers at

heavier weights and for more total dollars.

Excessive conditioning or fattening of suckling heifers may

influence subsequent development of desired maternal traits (Holloway

and Totusek, 1973). A detrimental effect of above average maternal

environment during the early life of heifer calves on their subsequent

producing ability has been shown by Mangus and Brinks (1971), Kress and

Burfening (1972) and Beltran (1978). Swanson (1960) and Holtz et al.

(1961) suggested that over-conditioned dairy heifers deposited excess










fat in their mammary system, and that this decreased future milk pro-

duction potential.

The effects of growth stimulants on future reproductive performance

of heifers are not well known. An important issue, from the producer's

point of view, is not whether creep feeding and growth stimulants

improve weaning weight, but how these practices affect future productive

potential of replacement heifers.

The purpose of this portion of the study was to evaluate the effects

of creep feeding, preweaning zeranol implants and breed type on repro-

ductive tract development, fat deposition in the udder, and body compo-

sition of weanling heifers.

Experimental Procedure

The preweaning creep feeding, zeranol treatments and breed types

compared in this study were described previously (Prichard et al.,

1988). Twenty-four weanling heifers used in this study were slaughtered

one day following weaning at about 7 mo of age. The gastrointestinal

tract from each heifer was cleaned of digesta for determination of empty

body weight. Carcasses were USDA quality and yield graded after a 24-h

chill at 1 to 2 C. The 9-10-11 rib section from the right side of each

carcass was removed and physically separated into fat, lean and bone to

estimate separable carcass components, as outlined by the procedure of

Hankins and Howe (1946). The soft tissue components (lean .plus fat) of

the 9-10-11 rib section were thoroughly mixed, ground and analyzed for

chemical composition by AOAC (1980) procedures. Chemical determinations

of the soft tissue components were used to estimate edible fat, protein

and moisture, according to the prediction equations developed by Hankins

and Howe (1946).










Reproductive tracts were removed from each heifer at time of

slaughter. Ovaries were weighed, measured and follicles larger than 3

mm in diameter were counted. Uterine weight (horns and body of uterus)

was recorded, and the outside diameter of the right uterine horn was

measured at the bifurcation. The udder was removed and weighed. One-

half of each udder was ground and sampled for percent lipid. Percent

lipid was determined using the Soxhlet Ether Extraction procedure

according to AOAC (1980).

Adipose tissue samples were taken from the udder and tail-head

region of each heifer. The subcutaneous sample from the tail-head

region was taken 5 cm to the right of the tail-head. Three thin slices

(approximately 200 mg) were obtained from each tissue sample using a

Stadie-Riggs microtome. Slices were fixed with 5 ml of 3% osmium

tetroxide and 3 ml of 50 mM collidine-HCL buffer solution (pH 7.4), as

described by Hirsch and Gallian (1968). The connective tissue matrix

surrounding the adipocytes was solubilized with 8 M urea as described by

Etherton et al. (1977). Adipocytes were rinsed through a 250- m nylon

screen with distilled water containing .01% triton X-100 (pH 10) into

200 ml volumetric flasks. A NaC1 solution (.154 M) was added to

increase volume to 200 ml. Duplicate 10 ml aliquots were removed from

each flask, added to 190 ml of a 45% sucrose solution, counted and sized

using a Coulter Counter Model TA II. A 560- m aperture was used. A

77.8- m standard of corn pollen was used to determine the volume of each

of the instrument's 16 channels. Standard particles and fixed

adipocytes were assumed to be spherical.

Data were analyzed by least-squares, fixed model procedures using

the Statistical Analysis System (SAS, 1979). The model used to analyze










all response variables included the fixed main effects of year, creep

treatment, zeranol treatment, breed of sire and breed of dam. Age at

the time of slaughter was included as a covariate. All interactions

were pooled and remained in the error term. Linear contrasts of the

least-squares means for creep treatments were computed for all response

variables affected (P<.10) by creep treatment.

Results and Discussion

Reproductive Tract Development. Least-squares means and probability

values for reproductive tract characteristics are shown in table 1.

Creep treatment did not affect (P>.19) ovarian weight, ovarian size,

uterine horn diameter nor follicle number of weanling heifers. Long-

term (LC) and short-term (SC) creep-fed heifers tended (P<.11) to have

heavier uterine weights than noncreep-fed (NC) heifers. No comparable

data were found in the literature. Cornwell (1981) fed long-yearling

heifers on three levels of nutrition and reported no significant effect

of nutritional level on ovarian size or weight or on uterine horn

diameter. Research by Hill et al. (1970) and Spitzer et al. (1978),

using long-yearling and yearling heifers, respectively, indicated that

ovarian size was reduced when heifers were on a restricted plane of

nutrition.

Heifers implanted with 36 mg of zeranol at 56 and 146 d of age had a

greater (P<.03) uterine horn diameter and heavier (P<.02) uterine weight

than non-implanted heifers. There was no effect (P>.20) of zeranol

implant on ovarian weight, size or number of follicles.

Breed of dam did not affect (P>.17) the development of the repro-

ductive tract of the weanling heifers. Brahman-sired heifers had a

greater ovarian weight (P<.04) and size (P<.02) than Romana Red-sired










heifers. Uterine horn diameter, uterine weight and follicle number were

not affected (P>.14) by breed of sire. The differences in ovarian

weight and size due to breed of sire may have been due to differences in

size of the heifers. Brahman-sired heifers weighed more (P<.02) at

slaughter than Romana Red-sired heifers (233 vs 211 kg). Foley et al.

(1964), using dairy cattle of all ages, reported a significant

correlation (.65) between weight of both ovaries and live weight. They

stated that age and live weight appeared to have more effect on ovarian

weight than did breed. However, the LC heifers in this study were

heavier (P<.02) at slaughter than NC heifers, yet there were no differ-

ences in ovarian size and weight due to creep treatment. Therefore, the

differences found in ovarian size and weight between the Brahman and

Romana Red-sired heifers may have been due to genetic differences,

independent of body size.

Udder and Subcutaneous Fat. Creep feeding did not increase (P>.25)

udder weight, percent lipid nor total lipid in the udder (table 2).

Though not significant, the least-squares means would indicate a

tendency for heifers to deposit more fat in the udder as length of creep

feeding increases. The NC heifers had a greater (P<.02) number of

adipocytes per g of udder tissue than did the LC and SC heifers;

however, the total number of adipocytes in the udder was not affected

(P>.58) by creep treatment. The LC heifers had larger (P<.04) udder and

subcutaneous adipocytes than NC heifers (166.0 and 166.7 m vs 152.7 and

148.8 m, respectively). The SC heifers tended (P<.15) to have larger

udder and subcutaneous adipocytes than NC heifers. Subcutaneous

adipocyte number per g of tissue was not affected (P>.49) by creep

treatment. Figure 1 illustrates the size distribution of adipocytes by










creep treatment. The LC and SC heifers had higher (P<.10) percentages

of total adipocyte volume composed of adipocytes greater than 160 m in

diameter than did NC heifers, whereas NC heifers had the highest (P<.05)

percentage of total adipocyte volume made up of adipocytes less than 129

m in diameter.

Data reported by Hood and Allen (1973), Allen (1976) and Garbutt et

al. (1979) indicate that adiposity in cattle may be influenced by

nutritional treatment during periods of growth and development. Allen

(1976) stated that changes in bovine cellular hypertrophy and hyper-

plasia are dependent on the location of the fat depot. He indicated

that intramuscular lipid accumulation is more dependent on cellular

hyperplasia than are subcutaneous depots. Results of this study would

indicate that cellular hypertrophy had occurred in the udder and sub-

cutaneous fat depots of creep-fed heifers. Therefore, any increase in

lipid accumulation in these fat depot areas would be due primarily to

adipocyte hypertrophy rather than hyperplasia.

Zeranol implants did not affect (P>.98) udder weight. Percent udder

lipid was lower (P<.02) in heifers implanted with zeranol; however,

total udder lipid was not affected (P>.68). Implanted heifers had more

(P<.07) adipocytes per g of udder tissue and tended (P<.14) to have

smaller udder adipocytes than non-implanted heifers. Total udder

adipocytes did not differ (P>.22) between implanted and non-implanted

heifers (8.55 and 7.06 x 109, respectively). Zeranol treatment did not

affect (P>.65) number of subcutaneous adipocytes per g of tissue;

however, implanted heifers had smaller (P<.10) subcutaneous adipocytes

than non-implanted heifers. Size distribution of udder and subcutaneous

adipocytes by zeranol treatment is shown in figure 2.










Heifers out of Angus dams had smaller (P<.08) udders and less

(P<.10) total fat in the udder than those from F1 dams (2.91 vs 3.49 kg

and 2.37 vs 2.86 kg). Breed of dam did not affect (P>.44) percent lipid

in the udder. Total udder adipocytes and udder adipocytes per g of

tissue were not affected (P>.35) by breed of dam. Heifers out of Fl

dams tended (P<.12) to have larger udder adipocytes than those produced

by Angus dams. Subcutaneous adipocyte size and number were not affected

(P>.61) by breed of dam.

Brahman-sired heifers had larger (P<.001) udders (3.85 vs 2.55 kg)

and more total fat in their udders (3.15 vs 2.08 kg) than Romana

Red-sired heifers. Percent lipid in the udder, however, was unaffected

(P>.78) by breed of sire. Number of udder adipocytes per g of tissue

was not affected (P>.31) by breed of sire. But as a result of more

total fat in the udder, Brahman-sired heifers had more (P<.004) total

adipocytes than those sired by Romana Red bulls. Romana Red-sired

heifers, however, tended (P<.14) to have larger udder adipocytes than

Brahman-sired heifers. In addition, Romana Red-sired heifers had fewer

(P<.08) adipocytes per g of subcutaneous adipose tissue but larger

(P<.09) subcutaneous adipocytes than those sired by Brahman bulls.

Breed type has been used to provide an explanation for differences

in adiposity in several studies; however, there have been few studies

specifically designed to investigate variations in adipocyte size and

number among breeds. Hood and Allen (1973, 1975) reported that

perirenal and subcutaneous adipose tissue in 14-mo-old Hereford x Angus

steers contained larger cells than the respective tissues from Holstein

steers of similar age and live weight. In addition, they observed that

a higher percentage of the total adipocyte volume for Hereford x Angus










steers was in the larger cell diameter ranges than for the same tissues

from Holstein steers. Figures 3 and 4 illustrate the distribution of

udder and subcutaneous adipocytes for breed of sire and breed of dam.

Carcass Characteristics and Composition. Least-squares means for

carcass characteristics and composition are shown in tables 3, 4 and 5.

The LC heifers had heavier (P<.005) empty body weights and less (P<.02)

gastrointestinal tract (GIT) fill than NC heifers. The LC heifers also

had heavier (P<.002) hot carcass weights and higher (P<.02) dressing

percentages than NC heifers. The LC heifers had heavier (P<.10) empty

body and hot carcass weights than SC heifers, but there was no dif-

ference (P>.21) in GIT fill or dressing percentage between heifers of

the two creep treatments. The SC heifers did not differ (P>.10) from NC

heifers for empty body weight, GIT fill, hot carcass weight or dressing

percentage.

Yield grade was not affected by creep treatment; however, carcasses

from LC heifers had more (P<.06) KPH fat, greater (P<.003) fat thick-

nesses and larger (P<.007) ribeyes than NC and SC heifers. Carcasses

from SC and NC heifers did not differ (P>.17) for KPH fat, fat thickness

or ribeye area. Ribeye area expressed as cm2 per 100 kg hot carcass

weight was not influenced (P>.84) by creep treatment. Creep treatment

did not affect (P>.47) marbling score, carcass maturity, lean color nor

fat color. Similar effects of long-term creep feeding on carcass

characteristics of weanling calves were reported by Scarth et al.

(1968), Corah and Bishop (1975) and Martin et al. (1980). Rouquette et

al. (1983), on the other hand, found no differences in carcass

characteristics between long-term and noncreep-fed calves.

Carcasses from LC heifers had a lower percent edible protein (P<.06)










than carcasses from NC and SC heifers (table 5). Creep treatment did

not affect (P>.26) percent edible fat or moisture in the carcass. The

LC heifers had a higher (P<.04) percent separable fat and tended (P<.11)

to have a lower percent separable lean content of the carcass than SC

and NC heifers. Carcasses from SC heifers had a higher (P<.07) percent

bone than carcasses from LC heifers, but did not differ (P>.17) from

those of NC heifers. Contrary to the above, Corah and Bishop (1975)

reported no difference in percent protein of carcasses between

noncreep-fed and creep-fed heifers slaughtered at weaning. Furthermore,

they observed that carcasses from noncreep-fed heifers had a higher

percent bone than those from creep-fed heifers.

The SC and NC heifers did not differ (P>.11) with respect to any

carcass trait including slaughter weight and hot carcass weight.

However, in the population from which these heifers were chosen, SC

calves were heavier (P<.001) at 210-d of age than NC calves.

Zeranol implants did not affect (P>.20) empty body weight, GIT fill,

hot carcass weight or dressing percent. Implanted heifers had higher

(P<.02) cutability carcasses (lower yield grade number) than non-

implanted heifers. Percent KPH and fat thickness were not affected

(P>.20) by zeranol treatment, but ribeye areas were larger (P<.06) in

the implanted heifers. The larger ribeye accounted for the lower yield

grade number of the carcasses from implanted heifers. Marbling score

and fat color were not affected (P>.41) by zeranol treatment; however,

zeranol implants increased lean color (P<.006) and maturity (P<.05), and

overall maturity (P<.07). Bone maturity was not affected (P>.17) by

zeranol. These results indicate that zeranol affects carcass traits

associated with body weight, and may increase maturity rate, as measured










by characteristics of the muscle. Gregory and Ford (1983), using late-

maturing bull calves, concluded that zeranol treatment effects on

carcass characteristics were of little consequence other than through

increases in body weight.

Estimated edible fat, protein and moisture in the carcass were not

affected (P>.30) by zeranol implants. Zeranol, however, did cause a

decrease in the percent separable fat (P<.09) and an increase (P<.008)

in the percent separable lean in the carcass. Percent separable bone

was not affected (P>.23) by zeranol treatment. Similar results for

estimated carcass components, using yearling steers, were reported by

Sharp and Dyer (1971).

Breed of dam did not affect (P>.23) empty body weight, GIT fill, hot

carcass weight nor dressing percent. Carcasses from heifers out of

Angus dams had more (P<.08) ribeye area per 100 kg of hot carcass weight

and tended (P<.11) to have less KPH fat than those out of F1 dams. This

resulted in a tendency for carcasses from heifers out of Angus dams to

be higher (P<.12) yielding than those out of F1 dams. Carcass fat

thickness, maturity, lean color and fat color were unaffected (P>.48) by

breed of dam. Estimated edible and separable carcass components were

not affected (P>.19) by breed of dam.

Brahman-sired heifers had heavier empty body (P<.009) and hot

carcass (P<.02) weights than Romana Red-sired heifers. Breed of sire

did not affect (P>.18) GIT fill, dressing percent, quality and yield

grade components, nor estimated carcass composition. These results are

in agreement with Koch et al. (1982) who mated Angus and Hereford cows

to various breeds of bulls and reported no differences in carcass

characteristics between Brahman and Sahiwal-sired steers, other than









Brahman-sired steers had heavier carcass weights.

These data indicate that an increase of subcutaneous fat in

long-term creep-fed heifers is due primarily to adipocyte hypertrophy.

Creep feeding also increases adipocyte size in the udder. Heifers

implanted preweaning with zeranol have a lower percent lipid in the

udder and smaller udder and subcutaneous adipocytes than non-implanted

heifers. Zeranol implants increase ribeye area and percent separable

lean and decrease percent separable fat in the carcasses of weanling

heifers.










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weaning traits in Brahman cattle. Ph.D. Dissertation. Univ. of

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Corah, L. R. and A. H. Bishop. 1975. Effect of creep feeding oat grain

to beef calves on their growth rate, carcass composition and

postweaning performance in a feedlot. Australian J. Exp. Agr. Anim.

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Cornwell, D. G. 1981. A comparison of the reproductive performance of

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Etherton, T. D., E. H. Thompson and C. E. Allen. 1977. Improved

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Foley, R. C., D. L. Black, W. G. Black, R. A. Damon and G. R. Howe.

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Garbutt, G. J., W. B. Anthony, D. F. Walker and J. A. McGuire. 1979.

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Gregory, K. E. and J. J. Ford. 1983. Effects of late castration,

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beef carcasses and cuts. USDA Tech. Bull. No. 926.

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Hirsch, J. and E. Gallian. 1968. Methods for the determination of

adipose cell size in man and animals. J. Lipid Res. 9:110.

Holloway, J. W. and R. Totusek. 1973. Relationship between preweaning

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Holtz, E. W., R. E. Erb and A. S. Hodgson. 1961. Relationship between

rate of gain from birth to six months of age and subsequent yields

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Hood, R. L. and C. E. Allen. 1975. Bovine lipogenesis: Effects of

anatomical location, breed and adipose cell size. Int. J. Biochem.

6:121.

Koch, R. M., M. E. Dikeman and J. D. Crouse. 1982. Characterization of

biological types of cattle (Cycle III). III. Carcass composition,

quality and palatability. J. Anim. Sci. 54:35.

Kress, D. D. and P. J. Burfening. 1972. Weaning weight related to

subsequent most probable producing ability in Hereford cows. J.

Anim. Sci. 35:327.










Mangus, W. L. and J. S. Brinks. 1971. Relationship between direct and

maternal effects on growth in Herefords. I. Environmental factors

during preweaning growth. J. Anim. Sci. 32:17.

Martin, E. L., D. G. Anderson Nelson and C. C. O'Mary. 1980. Carcass

traits of and preweaning creep feeding effects on steers sired by

Angus, Holstein, Simmental and Chianina bulls. J. Anim. Sci. 50:62.

Prichard, D. L., D. D. Hargrove, T. A. Olson and T. T. Marshall. 1988.

Effects of creep feeding, zeranol implants and breed type on beef

production: I. Calf and Cow Performance. J. Anim. Sci.(submitted).

Rouquette, F. M., Jr., R. R. Riley and J. W. Savell. 1983. Electrical

stimulation, stocking rate and creep feed effects on carcass traits

of calves slaughtered at weaning. J. Anim. Sci. 56:1012.

SAS. 1979. Statistical Analysis System User's Guide. SAS Institute

Inc., Cary, NC.

Scarth, R. D., R. C. Miller, P. J. Phillips, G. W. Sheritt and J. H.

Ziegler. 1968. Effects of creep feeding and sex on the rate and

composition of growth of crossbred calves. J. Anim. Sci. 27:596.

Sharp, G. D. and I. A. Dyer. 1971. Effect of zearalanol on the

performance and carcass composition of growing-finishing ruminants.

J. Anim. Sci. 33:865.

Spitzer,.J. C., G. P. Niswender, G. E. Seidel, Jr., and J. N. Wiltbank.

1978. Fertilization and blood levels of progesterone and LH in beef

heifers on a restricted energy diet. J. Anim. Sci. 46:1071.

Swanson, E. W. 1960. Effect of rapid growth with fattening of dairy

heifers on their lactational ability. J. Dairy Sci. 43:377.



















SUDDER


] SUBCUTANEOUS


ri


CREEP NC ISC LC NC SC LC NC SC LC NC LC NCC SC LC NC S LC
TREATMENT I I


DIAMETER, .m


8-25


26-80


81-128


129-160


161-202


203-320


Figure 1. Udder and subcutaneous adipocyte size distribution for noncreep (NC), short-term (SC) and
long-term (LC) creep-fed weanling heifers.


40.0 r


35.0

30.0

25.0

20.0


15.0 -


10.0


5.0 -


::: :::
:::::::

















40.0
30 UDDER
n 35.0 -

S30.0 SUBCUTANEOUS

_ 25.0 .
I-
O 20.0

O 15.0

W 10.0

a. 5.0

ZERANOL NZ Z NZ Z NZ Z NZ Z NZ Z NZ Z
TREATMENT I I| I a _
DIAMETER, pmm 8-25 26-.7,0 81-128 129-160 161-202 203-320

Figure 2. Udder and subcutaneous adipocyte size distribution for weanling heifers not implanted (NZ) and
implanted (Z) with zeranol.

















Ij: UDDER



I SUBCUTANEOUS


DIAMETER, .Lm


Figure 3.
heifers.


8-25


26-80


81-128


129-160 161-202 203-320


Udder and subcutaneous adipocyte size distribution for Brahman and Romana Red-sired weanling


40.0

35.0

30.0

25.0

20.0

15.0

10.0

5.0


0

I


li.
0
I-


U
0:
(L














UDDER

H SUBCUTANEOUS


DIAMETER, p.m 8-25 26-80 81-128 129-160 161-202 203-320

Figure 4. Udder and subcutaneous adipocyte size distribution for weanling heifers from Angus and F1 Angus
x Brown Siwss dams.


40.0

35.0

30.0

25.0

20.0

15.0

10.0

5.0









TABLE 1. LEAST-SQUARES MEANS FOR REPRODUCTIVE TRACT CHARACTERISTICS


Uterine Number
Source of Ovarian Ovarian3 horn Uterine of
variation n weight, g size, cm diameter, mm weight, g follicles


Creep treatment
Probability level
No creep
Short-term
Long-term

Zeranol treatment
Probability level
No zeranol
Zeranol

Breed of sire
Probability level
Brahman
Romana Red

Breed of dam
Probability level
Angus
F1

Mean
RSDC


.37
2.06
2.50
2.71


.24
2.66
2.18


.04
2.87
1.97


.17
2.69
2.15

2.42
.91


.19
2.87
4.08
4.50


.20
4.31
3.32


.02
4.81
2.82


.18
4.32
3.31

3.82
1.73


.45
13.94
15.04
15.27


.03
13.61
15.89


.32
15.22
14.28


.59
14.50
15.00

14.75
2.17


.11
22.86
33.76
29.51


.02
23.44
33.97


.14
31.88
25.54


.49
27.32
30.10

28.71
9.55


aYear influenced ovarian size
bTotal of both ovaries.
CResidual standard deviation.


(P<.10) and number of follicles (P<.04).


.21
10.20
15.30
21.00


.90
15.20
15.80


.67
16.60
14.40


.27
18.20
12.80

15.50
11.40









TABLE 2. LEAST-SQUARES MEANS FOR UDDER AND SUBCUTANEOUS FAT PARAMETERS


Total Udder Total Udder Subcutaneous Subcutaneous
Udder Udder udder adipocyte Udder adipocyte adipocyte adipocyte
Source ofa weight, lipid, lipid, number/g6 adipocyte diameter, number/g diameter,
variation n kg % kg tissue (10 ) number (10 ) m tissue (10 ) m

Creep treatment
Probability level .25 .43 .28 .02 .58 .09 .49 0.08
No creep 8 2.89 79.82 2.35 3.05 8.60 152.70 3.36 148.80
Short-term 8 3.18 80.82 2.58 2.12 7.19 162.80 2.94 160.20
Long-term 8 3.54 82.56 2.91 2.13 7.63 166.00 2.93 166.70

Zeranol treatment
Probability level .98 .02 .68 .07 .22 .14 .65 .10
No zeranol 12 3.20 83.53 2.67 2.16 7.06 164.30 3.00 164.10
Zeranol 12 3.21 78.61 2.55 2.71 8.55 156.70 3.15 153.00

Breed of sire
Probability level .001 .78 .002 .31 .004 .14 .08 .09
Brahman 12 3.85 80.82 3.15 2.58 9.77 156.70 3.39 152.80
Romana Red 12 2.55 81.32 2.08 2.29 5.84 164.30 2.76 164.30

Breed of dam
Probability level .08 .44 .10 .35 .52 .12 .69 .61
Angus 12 2.91 80.39 2.37 2.56 7.44 156.50 3.15 156.90
F1 12 3.49 81.76 2.86 2.30 8.17 164.40 3.01 160.20

Mean 24 3.20 81.07 2.61 2.43 7.81 160.50 3.08 158.50
RSD .75 4.16 .68 .66 2.72 11.70 .79 14.90

year influenced (P<.04) all traits except % lipid in the udder.
Residual standard deviation.









TABLE 3. LEAST-SQUARE MEANS FOR EMPTY BODY WEIGHT, GASTROINTESTINAL TRACT FILL,
HOT CARCASS WEIGHT AND DRESSING PERCENT


Empty Gastrointestinal Hot
Source ofa body tract fill, carcass Dressing,
variation n weight, kg kg weight, kg %


Creep treatment
Probability level
No creep
Short-term
Long-term

Zeranol treatment
Probability level
No zeranol
Zeranol

Breed of sire
Probability level
Brahman
Romana Red

Breed of dam
Probability level
Angus
F.


Mean
RSDc


.02
195.30
209.50
226.20


.26
205.80
214.90


.009
222.10
198.70


.23
205.50
215.20


24 210.40
18.70


.06
13.80
11.60
9.30


.66
11.20
11.90


.40
11.00
12.20


.41
12.10
11.00

11.60
3.30


.007
122.90
133.40
145.70


.20
130.60
137.40


.02
140.80
127.20


.25
131.00
137.00

134.00
12.10


.06
62.85
63.74
64.37


.47
63.47
63.84


.22
63.34
63.97


.78
63.72
63.58

63.65
1.17


aYear influenced hot carcass weight (P<.04) and dressing % (P<.004).
Dressing % = (hot carcass weight/empty body weight) x 100.
cResidual standard deviation.









TABLE 4. LEAST-SQUARES MEANS FOR CARCASS CHARACTERISTICS


Ribeye
USDA Fat Ribeye area/100 kg d
Source of yield KPH, thickness, area, hot carcass, Marbling Maturity Lean Fat
variation n grade % cm cm cm score lean bone overall colore color


Creep treatment
Probability
level
No creep
Short-term
Long-term

Zeranol treatment
Probability
level
No zeranol
Zeranol

Breed of sire
Probability
level
Brahman
Romana Red


.22
2.30
2.20
2.50


.02
2.50
2.10



.66
2.40
2.30


.06
2.42
2.49
3.28


.20
2.93
2.52



.99
2.73
2.73


.003
.40
.41
.75


.007
43.70
46.60
51.40


.004
44.30
50.10



.18
48.40
46.00


.84
36.00
35.00
35.40


.06
34.00
36.90



.25
34.60
34.30


.71
3.50
2.70
3.80


.41
3.80
2.90



.94
3.30
3.40


.52
C 85
C 71
C 83


.05 .17
69 C 72
94 C 88


.52
C 81
C 73
C 87


.07
C 70
C 91


.81 .87 .83
83 C 81 C 82
80 C 79 C 79


.52
4.70
4.80
5.20


.006
4.40
5.50



.57
4.80
5.00


.94
2.20
2.20
2.20


.55
2.30
2.10



.55
2.10
2.30









Table 4. Continued.


Ribeye
USDA b Fat Ribeye area/100 kg d
Source of yield KPH, thickness, area, hot carcass, Marbling Maturity Lean Fat
variation n grade % cm cm cm score lean bone overall color color


Breed of dam
Probability
level .12 .11 .99 .63 .08 .69 .60 .69 .59 .48 .65
Angus 12 2.20 2.48 .52 47.60 36.70 3.10 C 78 C 78 C 78 4.80 2.20
F1 12 2.50 2.98 .52 46.80 34.20 3.60 C 84 C 82 C 83 5.00 2.30

Mean 24 2.30 2.73 .52 47.20 35.50 3.30 C 81 C 80 C 80 4.90 2.20
RSD9 .3 .72 .19 4.10 3.20 2.60 C 27 C 26 C 24 .80 .60

year influenced (P<.02) lean color.
Kidney, pelvic and heart fat.
c2 = practically devoid average; 3 = practically devoid +; and 4 = traces -.
dEvaluated by percentages (0-100%) within a maturity score, C = calf.
eLean color scores were as follows: 4 = cherry red and 5 = moderately dark red.
Fat color scores were as follows: 1 = white; 2 = cream; and 3 = slightly yellow.
gResidual standard deviation.









TABLE 5. LEAST-SQUARES MEANS FOR ESTIMATED CARCASS COMPOSITION


Estimated carcass compositionb


Source of Edible Edible Edible Separable Separable Separable
variations n fat, % protein, % moisture, % fat, % lean, % bone, %


Creep treatment
Probability level
No creep
Short-term
Long-term

Zeranol treatment
Probability level
No zeranol
Zeranol

Breed of sire
Probability level
Brahman
Romana Red

Breed of dam
Probability level
Angus
F


Mean
RSDC


.26
22.66
21.55
23.63


.62
22.87
22.36


.65
22.84
22.38


.80
22.49
22.74


24 22.61
2.37


.06
17.42
17.38
16.50


.30
16.92
17.28


.73
17.04
17.16


.25
17.29
16.90

17.10
.79


.68
59.70
60.52
59.64


.84
59.86
60.05


.54
59.67
60.24


.81
60.06
59.84

59.95
2.14


.04
22.80
22.19
26.61


.09
25.15
22.59


.33
23.15
24.58


.91
23.95
23.78

23.87
3.32


.11
60.80
60.16
57.91


.008
57.90
61.35


.26
60.29
58.96


.48
60.02
59.22

59.62
2.68


.07
16.94
17.82
16.27


.23
17.33
16.69


.89
17.05
16.97


.19
16.67
17.36

17.01
1.22


bYear influenced (P<.02) percent edible fat and moisture and separable fat and leans.
Predicted using equations developed by Hankins and Howe (1946).
cResidual standard deviation.




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