. _ , ‘ ' - , - - i’ ' ’ ' ‘ ' ‘. ‘ x. . _ \ . , ' _ 4 [Blank Page in Original Bulletin] Contents ..................................................................................... .. 4 tion ............................................................................... .. 5 g e ................................................................................... .. 6 and Discussion .......................................................... .. 6 f» lice of Diethylstilbestrol on Suckling Calves .... .. 6 ncc of Diethylstilbestrol on ,rowth During a Wintering Period ...................... .. 7 i» ncc of Diethylstilbestrol on , erformance During the Finishing Period ............ .. 8 ‘~- Shrink, Cooler Shrink and ssing Percent ............................................................ .. 8 iass Grades and Price Per Pound .......................... .. 8 _--- Statement .......................................................... .. 8 ons ................................................................................. ..l0 e Cited ........................................................................ ..10 Acknowledgment! The assistance of Professor john H. Jones in planning and conducting this work in its earlier phases is gratefully acknowl- edged. The stilbestrol implants used in this work were provided by Charles Pfizer Inc., Terre Haute, Indiana and Discan Cor- poration, Los Angeles, California. Invaluable cooperation given by Las Moras Ranch of Menard, Merrill Ranch of Fort Davis, and Joe Lane Ranch of Marfa is gratefully acknowledged. Cover photo—courtesy of the Texas Hereford Association. The picture was taken on Las Moras Ranch, Menard. Summary Implanting 3-month-old suckling steer calves with I milligrams (mg) of diethylstilbestrol increased weaning we’ under West Texas range conditions by approximately f pounds, an average for 4 years. The weight advantage of implanted calves ranged from 2 pounds less to 29 pou; more than the unimplanted calves on the “Tlsame ranch du: the 4 years. Implanting appeared to be most effectivef, increasing weaning weight when range feed conditions i best. ’ Half to all of the weight advantage gained by f planting suckling calves was lost during subsequent wint; unless the weaned calves were re-implanted with 24 m diethylstilbestrol at the beginning of the wintering pet‘ The weaning weight advantage was maintained by re-imp ing, and the re-implanted calves showed the same res,‘ during wintering as did those which were implanted fof first time with 24 mg. at the start of wintering. i Some increase in weaning weight may be expected implanted suckling calves, but this effect does not e’! beyond weaning time at 7 to 8 months of age. Implai weaned calves at the start of wintering also gave som sponse in gain which, however, appeared to be indepe of previous implanting during suckling. '1 Steers implanted with 36 mg. of diethylstilbestrol a start of the finishing period following wintering gained. percent more and required 12.5 percent less feed per Q gain than did steers not implanted at start of finishin 12-mg. implant during the suckling period followed by mg. implant during the wintering period significantly dep ' subsequent feedlot gain when the cattle were given a 3, implant at the start of finishing but not when the implant was not used. One implant during either ‘su or wintering did not significantly depress feedlot gains the cattle were re-implanted for finishing. i Maximum gain was produced by a 24-mg. implanT ing wintering, followed by a 36-mg. implant during fin‘ Diethylstilbestrol should be used in, the finishing peri cause the response is greatest when nutrient intake is h__ Implanting with 36 mg. at the start of the fi period lowered carcasses about a third of a grade, bu ‘ was little difference in grade among none, one or t plants before the finishing period. ' i Figure 1 shows the 4-year average gain for each .2 and treatment. ' YLSTILBESTROL, DES, is a synthetic compound paving hormone-like properties similar to the _ estrogens, which are a group of female sex nes. _. e response of steers to diethylstilbestrol has studied in numerous experiments in recent Most of these studies have been concerned j fattening in drylot on rations comparatively _'in energy. They have demonstrated conclu- f that diethylstilbestrol, either implanted or fed , results in increased rate of gain and improved efficiency. ummaries on most of the experiments reported e use of diethylstilbestrol in the feedlot up to show a 14.2 to l7-percent increase in feedlot with an increase in feed efficiency of 9.8 to 12 t (23, 24). Later trials showed increases in 1t gain ranging from 9 to 16.3 percent and im- d feed efficiency from 2.7 to 11.4 percent (9, 26). Carcass grades of treated cattle ranged fslightly lower to slightly higher but were not A 'cantly different from those of nontreated cattle. ii he response of calves to diethylstilbestrol dur- 5i suckling period and of weaned calves or year- on pasture has been less thoroughly studied, ‘existing reports have shown variable results. milligram (mg.) implant administered to suck- calves resulted in ll pounds less gain to 53 .1 more gain at weaning than nonimplanted y (l, 2, 6, 15, 18, 19). Calves implanted during lckling period and re-implanted, or fed diethyl- trol, during a subsequent feedlot period con- ‘ to gain faster in some trials, while in other * (2, 6, l6, 17) their gain was significantly less “that of the controls. » eaned steer calves or yearlings implanted with .48 mg. of diethylstilbestrol during a wintering J mering period gained more than controls. i they were reimplanted or fed diethylstilbestrol f; a subsequent feedlot period, gains were de- in in some trials} in other trials there was no . ing effect when they were compared with 1 tively, formerly associate animal husbandman in charge, f“ k Unit, Trans-Pecos Experiment Station, Balmorhea; 31.0 iate animal husbandman, Livestock and Forage Re- Center, McGregor; and professor, Department of Animal , Texas A&M University. 4' f Response of Steers t0 Implantation of Dietlaylsti l bestrol During Suckling Wintering and Finishing Periods A. A. Melton and J. K. Riggs* those receiving diethylstilbestrol for the first time during the feedlot period (3, 4, 8, 10, ll, l3, 14, 21, 27). The effect on carcass grades also was variable. Results of trials in which steer calves were im- planted during a wintering period, implanted again during a summering period and given a third im- plant during a feedlot period showed that previous implants may or may not depress gains during either of the last two periods, when compared with those animals receiving their first implant during that particular period (5, 7, 16, 17, 22). Many cattle feeders have questioned the prac- tice of implanting feeder cattle with diethylstilbestrol at any time before the final finishing period because of possible lowered subsequent performance in the feedlot. This is a natural concern and many feeder buyers believe there should be some price discrimi- nation against implanted cattle, since it is believed these cattle may not perform as well in the feedlot or respond as well to further hormone treatment as those not previously implanted. This is a problem of considerable economic importance. The experiments reported in this bulletin were initiated to study the effect of diethylstilbestrol im- plants on weaning weights of suckling calves under range conditions, and the effect of these preweaning implants on subsequent gains of weaned steer calves on pasture and later as yearlings in the feedlot, when implanted during each of these periods. The study covered a 4-year period. I000 i Suckling Winluinq Cl Finilhinq BOB I = lmplunl B30 9'9 U O O l O O O Cumulative Gain in Pounds ‘ ~l o o Treatment Groups Figure l. Gains of steers implanted with diethylstilbestrol during suckling, wintering and finishing phases. TABLE 1. DESIGN OF THE EXPERIMENT AND DIETHYLSTILBESTROL TREATMENTS Treatment periods 80 suckling steer calves Suckling 40 implanted 40 not period 12 mg. implanted Wintering 20 implanted 20 not 20 implanted 20 not period 24 mg. implanted 24 mg. implanted Finishmg im llalhted 1° m" im llzfnted 1° m‘ im llzfiited 1° n“ I llfnted 1° ml period 3g mg. ‘implanted 3g mg implanted 3E mg. implanted 3g mg implant PRQCEDURE then turned on grain sorghum stalk fields ‘ The design of the experiment and the diethyl- stilbestrol treatments’ used are included in Table 1. During 1959-62 approximately 40 Hereford steer calves were made available by each of two ranches each year. Las Moras Ranch of Menard County in Central Texas provided calves all 4 years, and the Lane Ranch, near Marfa in the Davis Mountain area of the Trans-Pecos region, provided calves the last 3 years. The Merrill Ranch of Fort Davis pro- vided calves from that area the first year. The calves were dropped in January, February and March. They were tattooed and birth dates were recorded. Half of the calves were implanted with 12 mg. of diethylstilbestrol about June 1 each year. After 1959, the calves were from known sire groups, so that half the calves from each sire were implanted using alternate birth dates to determine which in- dividuals were to be implanted. This permitted division of the sire groups through all three periods of the experiment and aided materially in reducing variablility. The calves were weaned in September or October and trucked to the Livestock Unit, Trans-Pecos Ex- periment Station, Balmorhea, for wintering and fat- tening periods. They were kept on growing rations for 4 to 6 weeks after arrival at the station and TABLE 2. PERCENTAGE COMPOSITION OF FATTENING RATIONS Years Ingredients 1960 1961 1962 1963 Cottonseed meal 6.0 6.2 6.8 6.1 Ground alfalfa hay 3.3 4.0 6.0 6.4 Ground hegari fodder‘ 18.0 18.6 20.8 —— Cottonseed hulls 12.5 14.9 16.8 27.5 Ground grain sorghum 60.2 56.3 49.6 60.0 Total 100.0 100.0 100.0 100.0 Concentrates 72.0 68.0 62.0 66.0 Crude protein’ 11.1 11.0 11.1 10.8 Digestible protein’ 7.9 7.8 7.7 7.6 Total digestiible nutrients’ 69.2 67.9 65.9 67.8 ‘Hegari fodder contained approximately 30 percent grain each year. zCalculated using values given by Morrison, Feeds and Feeding, 22nd edition. 6 green oats for the winter, except during the win of 1962-63 when no green oat grazing was availa At the start of the wintering period, half of é- calves from each of the two original groups w‘ implanted with 24 mg. of diethylstilbestrol. g gave four groups for wintering. Following win ing periods of 120 to 161 days, half of each 0f_ four wintering groups were implanted with 36 " of diethylstilbestrol at the start of the finis a period, except in 1962. That year a 30-mg. impl of diethylstilbestrol plus 10 mg. in the ration 3 used daily. During the fattening period all groups were fed the same mixed ration as shown for each year a Table 2. E Each year the steers were sold on carcass I involving both grade and weight. In 1960, '. and 1963 the steers were trucked to Fort Worth, Q proximately 400 miles, and in 1962 they were truc- to Lubbock, approximately 225 miles, for slaugh They were rested for 36 to 48 hours after shipm before slaughter. Slaughter data were obtained year, but in 1962 the identity was lost in the y on about 20 percent of the carcasses. - RESULTS AND DISCUSSION Influence of Diethylstilbestrol on Suckling Calves The results of implanting suckling calves . shown in Table 3. The implanted calves had average weaning weight advantage of 25 pounds head at the Las Moras Ranch in Menard Cou the first 3 years. In 1962, the nonimplanted cal’ had a 2 pound weight advantage. This reversal 1962 may be partially explained because range u ditions were better the first 3 years. Diethylstilbesi response in cattle is better on fattening than on ~., ‘ ing rations and when pastures are good rather * - poor‘. All calves were from cows 3 years old or ol Range conditions were good in the Marfa- '2 Davis area in 1959 and the implanted calves shop an average advantage of 18 pounds in weaning wei The range conditions were not as good after ‘T. ERRATA Implanation of Diethylstilbestrol During B»1035, "Response of Steers to ge 6, right column, first paragraph, last fikling, wintering and Finishing;" pa jwtence, of diethylstilbestrol was This sentence should read: “"That year 10 mg. d at the start of the at in the ration daily and a 30~mg. implant was adde \§-ishing period." 3. THE INFLUENCE OF DIETHYLSTILBESTROL ‘A TS (l2 MG.) UPON WEANING WEIGHTS AND >OF SUCKLING STEER CALVES UNDER RANGE A CONDITIONS, 4-YEAR SUMMARY Menard County Davis Mountain Area Averages in pounds per calf _, 1959 Las Moras Ranch Merrill Ranch lanted i» r of calves 21 20 ping weight 508 496 2 -12 mg. diethylstilbestrol F- r of calves 21 20 j 'ng weight 528 514 advantage for implants 20 18 I 1960 Las Moras Ranch Joe Lane Ranch llanted a y, r of calves 19 16 '1 June 16 360 May 31 183 l‘ to Sept. 29 186 Oct. 21 219 _ -12 mg. diethylstilbestrol , v of calves 20 17 ‘u June 16 377 May 31 188 . to Sept. 29 215 Oct. 21 228 , advantage for implants 29 9 i 1961 Las Moras Ranch ]oe Lane Ranch lanted ber of calves 22 26 J June 9 345 June 5 225 ~10 Sept. 21 182 Oct. 16 25s d—l2 mg. diethylstilbestrol _ber of calves 22 27 d- june 9 361 June 5 218 to Sept. 21 207 Oct. 16 262 i advantage for implants 25 9 1962 Las Moras Ranch Joe Lane Ranch _'lanted ’ ber of calves 23 28 "g4 t May 24 296 May 29 203 to Sept. 25 207 Oct. 8 231 ted—12 mg. diethylstilbestrol 1w of calves 22 30 ht May 24 272 May 29 190 j to Sept. 25 205 Oct. 8 240 I advantage for implants -2 9 average ‘t advantage for implants 18 11 e weaning weight advantage for the implanted averaged 9 pounds per head for 1960-62. j calves were from 2-year-old heifers in 1960, g 2 and 3-year-old heifers in 1961 and from 3 : year-old cows in 1962. _l calves were graded at weaning time in 1959 The implanted calves averaged one-sixth of de higher than the nonimplanted calves. ¢ if uence of Diethylstilbestrol on Growth A During a wintering Period he results of the wintering periods are shown gable 4. Stalk fields and oats provided good ‘g for approximately 5 months during 1959-60 ;l960-61, and gains of approximately 2 pounds ay were recorded during March and April of those 2 years. Pastures were less productive in 1961- 62, and it became necessary to begin the feedlot period on March 19, 1962. No oat pasture was avail- able in 1962-63, limiting the grazing period for win- tering to 38 days on stalk fields (October 22 to November 29), after which the calves were placed in drylot on a fattening ration. ADuring all four wintering periods, calves im- planted only during the suckling period gained slightly less than calves not implanted at all, but the difference was significant only during the win- ter of 1960-61. Calves implanted only at the start of the wintering period and those implanted during suckling and start of the wintering period did not make significantly different gains in any of the 4 years. The average gain of those implanted for the first time during the wintering period was signifi- cantly greater each year, except in 1960-61, than of those implanted as suckling calves and those not implanted at all. Similarly, the average gain of those implanted as suckling calves and during wintering TABLE 4. WEIGHTS AND GAINS OF IMPLANTED AND NON-IMPLANTED STEER CALVES DURING WINTERING, 4-YEAR SUMMARY Implanted, suckling and wintering Controls, Implanted, Implanted, not suckling wintering implanted only only November 19, 1959 to April 28, 1960; 161 Days Averages in pounds per steer Number of steers 19 20 20 20 Initial weight, 11/19/59 581 603 578 595 Final weight, 4/28/60 800 821 828 831 Daily gain 136a 1.351 1.5511 1.4783’ December 2, 1960 to May l,’ 1961; 150 Days Number of steers 17 18 18 18 Initial weight, 12/2/60 524 569 520 563 Final weight, 5/1/61 722 737 724 775 Daily gain 1.32% 1.12b 136a 1.418- November 8, 1961 to March 19, 1962; 131 Days Number of steers 20 20 20 20 Initial weight, 11/8/61 525 536 520 544 Final weight, 3/19/62 655 661 691 710 Daily gain 0999- 0.959- 1.311) 1.271’ October 22, 1962 to February 19, 1963; 120 Days Number of steers 20 20 20 20 Initial weight, 10/22/62 514 504 514 499 Weight 11/29/62 566 552 567 555 Final weight, 2/ 19/63 788 764 826 816 Daily gain, 10/22/62 to 11/29/62 1.3911 126a 1.391 1.473 Daily gain, 10/22/62 to 2/19/63 228a 2179- 2.60b 2.641) Daily gain, 11/29/62 to 2/19/63 2.71 2.59 3.16 8.80 Average daily gain for 4 years 1.49 1.49 1.71 1.70 arbDaily gains showing different superscripts in the same year were significantly different at the 5 percent level of prob- ability. was greater than for those implanted as suckling calves and those not implanted, but the increase was not significantly greater in 1959-60 or in 1960-61. Under the conditions of this experiment, the average results for 4 years show that from half to all the advantage gained by implanting suckling calves was lost during wintering if the calves were not re-implanted at the start of the wintering period. The advantage gained by implanting as suckling calves was maintained during the wintering period if they were re-implanted at that time, and they showed the same advantage during wintering as those calves receiving their first implant during the period. Therefore, it seems clear that some response in wean- ing weight may be expected from implanting suck- ling calves, but this effect does not extend beyond weaning time of 7 to 8 months. Implanting weaned calves at the start of wintering also gave some re- sponse in gains which appear independent of the previous implant during suckling. Influence of Diethylstilbestrol on Performance During the Finishing Period Table 5 summarizes the finishing data for 4 years. Separate statistical analyses were made for each year. Steers implanted with 36 mg. at the start of the finishing period (lots 5, 6, 7 and 8) gained 20.7 percent more on 12.5 percent less feed than the average of those not implanted at that time (lots 1, 2, 3 and 4). However, the steers implanted at all three stages of development (lot 8) gained only 13.5 percent more on 5.4 percent less feed than the average of those not implanted. Average daily gains for the steers not implanted at the start of finishing were similar in all 4 years with no significant difference in any year. This indicated that one or two implants prior to the start of finish- ing did not increase or decrease feedlot gains when the cattle were not implanted at the beginning of the finishing period. Although daily gains for the steers implanted at start of finishing (lots 5, 6, 7 and 8) were more variable in all 4 years than for those not so implanted (lots 1, 2, 3 and 4), the 4-year average for those receiving no previous implant or getting one pre- vious implant (lots 5, 6 and 7) was almost the same, while the gain for those receiving all three implants (lot 8) was considerably lower. During 1960, the steers implanted previously as suckling calves (lot 6) gained significantly more than the other three groups (lots 5, 7 and 8), and those not previously implanted (lot 5) were the low gaining group. After 1960, however, the lot 5 cattle, previously unim- planted, gained the most. The gains for these four groups of steers followed the same pattern each year thereafter, with the steers first implanted at start 8 of finishing ranking highest, those previous] planted at start of wintering ranking second, previously implanted during suckling ranking ' and those previously implanted during both su and wintering ranked lowest in gain. The ga the steers implanted at the start of all three u: (lot 8) was not significantly lower than that ~I other three groups implanted at start of fin’) (lots 5, 6 and 7). However," it was not signifii above the highest gaining group not implant start of finishing (lots 1, 2, 3 and 4), except in. The results indicated that a 12-mg. imp l diethylstilbestrol during the suckling period .5? by a 24-mg. implant during the wintering _ depressed feedlot gains when the cattle were 7 a 36-mg. implant at the start of the finishing h‘ as compared with steers receiving their first or ' implants during the finishing period. One im during either the suckling or the wintering - did not significantly depress subsequent feedlot Shipping Shrink, Cooler Shrink and Dressing Percent During 3 of the 4 years there were si ' differences in shrink to market but no definit tern was shown, except that the average shri cattle implanted at finishing (lots 5, 6, 7 and 8 0.74 percent greater than for cattle not implan finishing (lots 1, 2, 3 and 4). ' In only l of 3 years was there a significa if ference in cooler shrink of carcasses, but aga: definite pattern was shown except that the -~ shrink for implanted cattle was less than forj not implanted. These two shrinks tended ‘I offsetting so that there was no significant diff in dressing percent among lots during any Carcass Grades and Price Per Poun Although carcass grade and price per I differed significantly among some of the grouf year, the only consistent pattern was that ca from steers which had never been implant, those implanted only as suckling calves graded Q2 and therefore brought a higher price per " Implanting after the suckling period tended 1 press carcass grade, and implanting during th lot period had the greatest depressing effect { grade and price. Heavier carcasses and lower f from those implanted at start of the finishing combined to depress price. Carcasses weighi a 700 pounds did not bring as much as did those‘ 700 pounds. ’T Financial Statement Considerable controversy frequently has i concerning the price of implanted and unim feeder calves at weaning time. Buyers so l: ' INFLUENCE OF REPEATED IMPLANTATION WITH DIETHYLSTILBESTROL UPON FEEDLOT PERFORM- AT’ ANCE OF FATTENING STEERS, 4-YEAR SUMMARY 1 2 3 4 5 6 7 8 ‘Steers ' 9 10 . 10 10 10 1O 10 10 8 8 8 8 8 8 8 8 10 l0 10 10 10 10 10 10 41 10 10 10 10 10 10 10 10 '3 : trol Treatment l2 mg. None Implanted None Implanted None Implanted None Implanted K_ '24 mg. None None Implanted Implanted None None Implanted Implanted "_ 36 mg. None None None None Implanted Implanted Implanted Implanted 1 'a1 weight, pounds K 800 I 826 833 829 800 827 823 830 709 713 728 748 709 713 727 747 655 661 691 710 655 661 691 711 ‘ 789 762 828 804 788 770 824 827 _1 yearé 738 741 770 773 738 743 766 779 4, -1 weight, pounds 1120 1140 1173 1146 1169 1263 1205 1218 1039 1033 1085 1071 1159 1130 1160 1130 1034 1018 1054 1084 1085 1066 1104 1098 1017 1018 1076 1050 1108 1079 1135 1108 years 1053 1052 1097 1088 1130 1135 1151 1139 1* y gain, pounds _ days 2.39 2.34 2.54 2.36 2.76 3.26 2.85 2.89 ‘f. days 2.29 2.22 2.48 2.25 5.15 2.90 5.00 2.66 z days 2.64 2.48 2.52 2.60 2.99 2.81 2.86 2.69 Vi" days 2.04 2.28 2.22 2.19 2.85 2.76 2.77 2.50 ‘years 2.34 2.33 2.44 2.35 2.93 2.93 2.87 2.69 ly ration, pounds ~ 28.72 28.47 29.82 28.74 28.03 30.12 31.78 30.90 25.56 25.30 26.71 27.68 30.42 29.12 26.68 29.89 29.65 26.39 28.50 29.72 29.00 28.57 30.57 29.44 22.93 24.67 27.12 28.15 26.87 25.09 25 .51 27.67 years 26.72 26.21 28.04 28.57 28.58 28.23 29.14 29.48 Aunds gain, pounds ' 1202 1216 1175 1216 1017 924 1117 1069 ' 1114 1140 1075 1233 973 1007 956 1125 A 1125 1065 1129 1144 992 1015 1067 1095 1125 1083 1223 1284 941 909 921 _ 1106 i ‘years 1142 1126 1151 1219 981 964 1015 1099 ' Fin 311k g , percent 6.32 5.76 6.56 4.73 6.47 7.12 5.92 6.83 5.74 5.51 7 .79 4.99 6.64 6.60 6.84 4.91 8.53 6.58 7.42 6.94 8.60 7 .90 7 .99 7 .92 z 3.05 4.31 3.31 4.22 4.36 4.94 4.61 4.68 :5 years 5.91 5.54 6.27 5.22 6.52 6.64 6.34 6.09 - rcent 7’ 64.79 65.03 64.25 64.17 64.67 65.02 65.83 64.80 62.69 62.49 63.50 62.60 62.53 63.30 63.46 62.98 j; 63.94 64.32 63.71 64.16 63.43 63.80 64.24 64.15 years 63.81 63.95 63.82 63.64 63.54 64.04 64.51 63.98 i nk, percent I chilled carcass 57 2.09 1.68 1.69 1.51 1.44 1.38 1.42 1.54 0.75 0.81 1.13 0.96 0.86 0.94 0.85 0.93 a 1.38 1.41 1.42 1.35 1.21 1.39 1.41 1.54 . years 1.41 1.50 1.41 1.27 1.17 1.24 1.25 1.20 . .de' ‘ 12.00 12.22 14.67 15.11 14.89 15.78 16.44 15.78 12.50 13.50 13.50 14.25 15.00 13.50 14.50 16.25 ; 12.40 12.40 15.00 11.00 15.20 15.00 16.00 14.60 years 12.30 12.71 14.39 13.45 15.03 14.76 15.65 15.54 i_ dollars per L-.. initial, feed ; keting costs ‘ 3.83 0.79 _8.78 -7.85 1.57 6.47 -2.54 -2.15 22.76 18.37 22.70 16.46 26.48 29.24 29.92 22.62 -> -_16.67 -17.11 _30.37 --24.24 _16.77 -12.31 -15.84 -22.82 is years ‘ 5.51 0.68 _5.48 _5.21 5.76 7.80 5.85 _0.78 grade code: 8, 10, 12—High, middle and 10w choice; 14, 16, 18—high, middle and 10w good, respectively. have maintained that implanted calves were worth less than those not implanted because they were heavier and because their future response to diethyl- stilbestrol might be lessened as a result of the treat- ment administered during the preweaning period. These factors tended to complicate evaluation of the overall results of these experiments. The producer of the steer calves used priced them the same despite any weight differences result- ing from early implanting. This would be the ex- pected reaction of sellers, probably justified in this case because the weight increase resulting from the suckling implant did not exceed. 30 pounds per head in any year. Should the weight increase from im- planting result in average weaning weights over 500 pounds as contrasted with weights under 500 pounds for unimplanted calves, common practice by contract buyers in the trade would be to discount the heavier calves a dollar per hundredweight. This practice also would apply to heavier as opposed to lighter yearlings at the end of the wintering period. Cost into the feedlot was determined in this study by adding wintering cost to purchase cost and dividing by the total weight of the cattle at the end of the wintering period. Price per hundredweight therefore was the same for all groups each year and cost per head varied only because of variation in weight. Marketing cost and feed cost during finish- ing were added to initial cost in the feedlot to give total cost. The cattle were sold on the basis of carcass weight and grade in order to get a true reflection of their market value resulting from hor- mone influences on carcass development. Returns per steer from the four groups im- planted at the start of the finishing period were greater every year than were returns from the four groups not implanted at that time. However, steers not implanted at all and those implanted only as suckling calves produced slightly greater returns than those which received three implants; at suckling, win- tering and finishing stages. Those implanted only during the wintering period and those implanted during both suckling and wintering periods showed a loss as an average of 3 years. CONCLUSIONS It is apparent that the- response of suckling calves to implantation with diethylstilbestrol varies from ranch to ranch and from 1 year to another on the same ranch. The evidence suggests that milk production of the dams as influenced by grazing conditions, supplemental feeding, age of dam and genetic potential of dam as determined by breeding and selection pressure for milk production or wean- ing weight, in different herds, may be a factor in calf response to implantation. Creep-fed calves, with com- paratively high energy intake during the suckling 10 period, might show greater response than w‘ corded here. ‘l Calves which were not re-implanted duri . wintering period after weaning seemed to lose of the weight advantage they gained from bei planted during suckling, but if re-implanted at ing they gained as well during the winter as i which received their first implant at that time. ; or two implants prior to the start of the fi period had no depressing effects on feedlot ’ of cattle not implanted for finishing, but t_ plants definitely depressed gain when the catt implanted with 36 mg. for finishing. LITERATURE CITED 1. Bell, T. Donald, J. J. Dahmen, and Wade Wells.. The performance of steers on pasture and in the as affected by stilbestrol implants. Idaho Agri Experiment Station Bulletin 334. » 2. Bradley, N. W., W. Y. Varney, R. R. Garrigus, Reitnour and Nelson Gay, 1962. Effect of stilbes’ plants during the pre-weaning period on postwean' lot performance of steers and heifers receiving s ' orally. Kentucky Agricultural Experiment Station ‘l Report 116, p. 22. ' 3. Bradley, N. W., David McKechnie, W. Y. Va v J. D. Kemp, 1963. Effect of stilbestrol implants K sequent feedlot performance and carcass. Univ Kentucky Agricultural Experiment Station Progress 131, p. 84. ~ 4. Brethour, John R. and W. W. Duitsman, 1960. Sti implants for steers wintered on native grass in a ing-grazing-fattening program. Fort Hays Branch, a Agricultural Experiment Station Circular 377, p. i’: 5. Brethour, John R. and W. W. Duitsman, 1962. v stilbestrol implants in a wintering-grazing pro Y steer calves. Fort Hays Branch, Kansas Agricultu‘ periment Station Bulletin 448, p. 4. » 6. Brethour, John R. and W. W. Duitsman, 1963. J stilbestrol implants for creep-fed steer calves. F0 A Branch, Kansas State University of Agriculture and A Science Agricultural Experiment Station Bulletin 29. 7. Ellis, George F. and J. H. Jones, 1960. Res’ steers to repeated implantation with stilbestrol. Agricultural Experiment Station Progress Report 2 8. England, David C. and Norton O. Taylor, 1962. ing weaner steers. Oregon State University Agri Experiment Station, Station Bulletin 587. A 9. Essig, H. W., 1961. The effects of diethylstilbestrol tranquilizer on beef cattle in Mississippi. Mississipi University Agricultural Experiment Station Techni letin 48. l0. Fontenot, J. P., R. F. Kelly and J. A. Gaines, 1961i influence of implanting graded levels of stilb grazing beef steers. Virginia Agricultural Experim tion Bulletin 522. T ll. Henderson, R. C., J. H. Jones and R. M. Smi H’ Stilbestrol imp1antation—pasture and feedlot. Tex. cultural Experiment Station Progress Report 2142. 12. Hentges, J. F., Jr., W. D. Fletcher, J. A. Black, Tucker, II and T. J. Cunha, 1960. Diethylstilbes aureomycin for fattening beef cattle. University of if Agricultural Experiment Station Bulletin 627. L. B. A., E. F. Smith, 1). Richardson and R. F. Cox, __‘ Response of previously implanted cattle to oral _ylstilbestrol. Kansas Agricultural Experiment Station 1.. lar 378, p. 8. -, Robert M., Keith E. Gregory, james E. Ingalls and H. Arthaud, 1959. Influence of hormone implants ins made on native pastures and in the feedlot, and ircass characteristics of yearling steers, j. Animal Sci. i 10. A. B., L. S. Pope, E. j. Turman and R. Totusek, u Stilbestrol and an antibiotic (Erythromycin) for f ling beef calves. Oklahoma State University Experi- t Station Miscellaneous Publication 55, p. 19. A. B., L. R. Kuhlman and L. S. Pope, 1961. Stil- rolifor range beef cattle. Oklahoma State University 'rnent Station Miscellaneous Publication 64,‘ p. 68. j .1 A. B., L. S. Pope and D. F. Stephens, 1960. Effect ‘stilbestrol implants on summer gains and subsequent lot performance of yearling steers. Oklahoma State iversity Experiment Station Miscellaneous Publication ‘ p. 113. t. A. B. and L. R. Kuhlman, 1962. Stilbestrol im- ts for fall calves. Oklahoma State University Experi- X t Station Miscellaneous Publication 67, p. 15. an, C. W., j. Y. Oakes and W. A. Nipper, 1962. i ylstilbestrol studies with beef cattle. Louisiana State 'versity and Agricultural and Mechanical College Agri- ‘a ral Experiment Station Bulletin No. 551. 20. 21. 22. 23. 24. 26. 27. Ogilvie, M. L., E. C. Faltin, E. R. Hauser, R. W. Bray and W. G. Hoekstra, 1960. Effects of stilbestrol in altering carcass composition and feedlot performance of beef steers. j. Animal Sci. 19:991. O’Mary, C, C. and A. E. Cullison, 1956. Effects of low level implantation of stilbestrol in steers on pasture. j. Animal Sci. 15:48. Radabaugh, D. V. and L. B. Embry, 1959. Diethylstil- bestrol for wintering, pasturing and fattening beef cattle. Agricultural Experiment Station, South Dakota State Col- lege Bulletin 475. Radabaugh, D. V. and L. B. Embry, 1959. Summary of research on diethylstilbestrol for growing and fattening beef cattle. Agricultural Experiment Station, South Dakota State College Department Pamphlet Number 2. Riggs, j. K., 1958. ‘Fifty years of progress‘ in beef cattle nutrition. j. Animal Sci. 17:981. Smith, E. F., B. A. Koch, F. W. Boren and B. D. Carmack, 1960. Stilbestrol implants for steer calves on wintering, grazing and fattening; the value of aureomycin during the wintering and fattening periods, 1958-1959. Kansas Agri- cultural Experiment Station Circular 378. Wheeler, R. F., S. G. Woods, R. L. Edwards and C. W. Ackerman, 1960. Diethylstilbestrol in fattening rations for dry-lot steers. South Carolina Agricultural Experiment Station Bulletin 483. Woods, Walter, 1962. Effect of implantation followed by feeding of stilbestrol on steer performance and carcass characteristics. j. Animal Sci. 21:533. ll obmsod p: guauxinnd 10m agnnpd m; Aunue; L,» R n‘: SSHNISIIH ‘IYIDL-HO 90H lFn-"d ssezfioxd 1o uodeg 1o ugennq 1o podeg [nnuuy-uoggnaggqnd xopazgq 17g“, snare; ‘uoggmg ebenog uogmg guewpedxg [mnqnagzby snare; Mgszequn yqyy snxe;