Numerous experiments have shown improvements in growth rate and feed efficiency when feedlot lambs are implanted with 12 mg zeranol (trade name Ralgro) or 3 mg diethylstilbestrol (DES). Differences in feedlot performance between the two implants have been small and somewhat variable

Dunn, B. H.

Embry, L. B.

English

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South Dakota State UniversityOpen PRAIRIE: Open Public Research Access InstitutionalRepository and Information ExchangeSouth Dakota Sheep Field Day Proceedings andResearch Reports, 1977 Animal Science Reports1977Zeranol and Diethylstilbestrol Implants for FeedlotLambsB. H. DunnSouth Dakota State UniversityL. B. EmbryFollow this and additional works at: http://openprairie.sdstate.edu/sd_sheepday_1977This Report is brought to you for free and open access by the Animal Science Reports at Open PRAIRIE: Open Public Research Access InstitutionalRepository and Information Exchange. It has been accepted for inclusion in South Dakota Sheep Field Day Proceedings and Research Reports, 1977 byan authorized administrator of Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. For moreinformation, please contact michael.biondo@sdstate.edu.Recommended CitationDunn, B. H. and Embry, L. B., "Zeranol and Diethylstilbestrol Implants for Feedlot Lambs" (1977). South Dakota Sheep Field DayProceedings and Research Reports, 1977. Paper 5.http://openprairie.sdstate.edu/sd_sheepday_1977/5• • • South Dakota State University Brookings, South Dakota Department of Chemistry and Animal Science Agricultural Experiment Station A.S. Series 77-7 Zeranol and Diethylstilbestrol Implants for Feedlot Lambs B. H. Dunn and L. B. Embry Numerous experiments have shown improvements in growth rate and feed efficiency when feedlot lambs are implanted with 12 mg zeranol (trade name Ralgro) or 3 mg diethylstilbestrol (DES). Differences in feedlot performance between the two implants have been small and somewhat variable. The required 120-day interval between implanting and slaughter for DES has been a disadvantage for the implant since many feeder lambs do not require a feeding period this long. The required interval between implanting and slaughter for zeranol is only 40 days. This allows the use of the implant for a large percentage of feeder lambs and reimplanting those requiring a long finishing period. Previous work at this station (Fmbry and Swan, A.S. Series 75-12) has indicated a small advantage for reimplanting with zeranol when compared to a single zeranol implant. The reimplant must be done at least 40 days prior to slaughter which might be beneficial for lambs to be fed for periods of 3 or more months. Based on these observations, this experiment was conducted to determine if reimplanting lambs with 12 mg zeranol would improve the feedlot performance as compared to an initial implant of 3 mg DES or 12 mg zeranol in a feeding period of about 4 months • Experimental Procedure This experiment was superimposed across treatments in an experiment studying the effects of graded levels of limestone supplementation (results in another report). The lambs were randomly allotted on the basis of weight to four treatment groups including a control, 12 mg zeranol, 12 mg zeranol plus 12 mg reimplant at 65 days and a 3 mg DES implant. There were four pens of 10 lambs each initially (five ewes and five wethers) per treatment group. The basal diet consisted of ground corn, 84.4%; ground alfalfa-brome hay, 8%; and soybean meal (44%), 6%, with supplementary minerals and vitamins A and E making up the remaining part. The pretreatment feed was baled alfafa-brome hay. On day one of the experiment, residual hay was removed from the feed bunks and the lambs were offered 3 lb of the complete mix diet per head. They were fed ad libitum for the remainder of the 121-day trial. The initial average weight of the lambs was 61 pounds. It was estimated that these lambs could be fed for the necessary 120 days to a reasonable market weight. The lambs were weighed every 21 days and feed consumption was recorded daily on a pen basis. Feed consumption and feed efficiency data were analyzed after being corrected for added limestone. The average weight at slaughter was 120 pounds. Carcass data were collected 24 hours after slaughter • Prepared for Sheep Field Day, June 10, 1977. 25 - 2 -Results Results obtained from implant treatments averaged for dietary treatments are shown in table 1. Dietary treatments appeared to have no effect on the response to implant treatments. During the first weigh period, some deaths did occur. The cause of death was diagnosed as rumen acidosis by the South Dakota Animal Disease Research and Diagnostic Laboratory. Data presented are only for animals finishing the experiment and feed consumption has been adjusted accordingly. During 1 to 64 days, lambs that were implanted had improved gains (P<.05) when compared to the nonimplanted controls. Differences in gain for those lambs receiving zeranol or DES were small at this time. During the interval from 65 to 121 days, lambs receiving a zeranol implant, zeranol implant plus reimplant or DES implant had 6.6, 32.6 and 13.4% higher average daily gains, respectively, than the nonimplanted controls. At the end of the experiment, gains averaged over the entire 121-day feeding period showed a 13.5, 25.5 and 16.5% improvement in average daily gain for those lambs receiving the zeranol, zeranol plus reimplant or DES treatment, respectively. Since implanted lambs made faster gains with similar feed intakes, the treatments also improved feed efficiency. At the end of the experiment, there were 5.1, 12.7 and 9.6% decreases in feed required per pound of gain for the lambs receiving the zeranol, zeranol plus reimplant or DES.treatments, respectively. Summary Results from this experiment show an advantage in weight gains and feed efficiency for the lambs implanted with DES or zeranol. The 13.5% and 16.5% improvements in weight gains for lambs receiving the zeranol and DES treatments, respectively, are higher than frequently reported. The implant treatments appeared to have no important effects on the carcass characteristics measured. When compared to initial implants of zeranol or DES, reimplanting with zeranol improved weight gains by 10.6 and 7.8%, respectively. This could be of major economic importance if the finishing period was 3 to 4 months in length and the reimplanting was done at about the mid-point of the feeding period. The improvement was somewhat higher in this experiment than previous work at this station had indicated. 26 • • • • • • - 3 -Table 1. Zeranol and DES Implants With High Concentrate Diets (August 20 to December 19, 1975--121 Days) No. animals Initial wt., lb Final wt., lb. Avg daily gain, lb 1-64 days 65-121 days 1-121 days Avg daily ration, lb 1-64 days 65-121 days 1-121 days Feed/100 lb gain, lb 1-64 days 65-121 days 1-121 days Carcass wt., lb Conformation gradea Maturityb Flank streakingC Featheringc Grad ea Dressing percent Control 27 61.2 113.4 .496 .359 .431 2.46 2.75 2.61 496 766 606 61.0 13.3 2.1 13.6 16.6 12.5 53.70 12 mg zeranol initially 33 60.4 119.5 .583* .383 .489* 2.65 3.00 2.81 455** 783 515* 63.5 13.2 2.1 13.7 16.3 12.5 53.12 12 mg zeranol initially and at 65 days 30 60.6 126.1 .599* .476 .541** 2.65 3.11 2.86 442** 653 529** 66.7 13.5 2.2 13.1 15.4 12.1 52.93 a Choice • 11, Prime = 14. Graded to one-third grade. b A- maturity = 1, A+ maturity= 3. c Slight= 11, Small= 14, Modest= 15. * Significantly improved over control (P<.05). ** Significantly improved over control (P<.01). 27 3 mg DES initially 27 60.9 121.7 .586* .407 .502* 2.50 2.67 2.75 427** 752 548** 63.5 13.4 2.2 13.0 16.2 12 .4 52.20 - ..... 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Sodium Bentonite and Sodium Bicarbonate in High-Concentrate (August 13 to October 27, 1975--75 Days) 1-21 days Basal 2% NaBa 2% NaB 2% NaHco3b 2% NaHC03 22-75 days Basal Basal 1% NaB Basal 1% NaHC03 No. animals 52 31 31 29 32 Initial wt., lb 72.8 72.4 72.3 72.3 72.4 Final wt., lb 113. 3 112.2 118.8 110.3 113.9 Avg daily gain, lb 1-21 days .365 .250 .537 .310 .345 u) 22-75 days .608 .640 .652 .583 .633 � 1-75 days .540 .531 .621 .507 .552 Avg daily ration, lb 1-21 days 1.89 1.66 2.20 1.83 1.91 22-75 days 3.21 3.22 3.39 3.17 3.24 1-75 days 2.84 2.78 3.06 2.80 2.86 Feed/100 lb gain, lb 1-21 days 518 664 410 590 554 22-75 days 528 503 520 544 512 1-75 days 526 524 493 552 518 a Sodium bentonite. b Sodium bicarbonate. NNNt:11:1 cN! cN! cN! Ill fl> NO> fl> fl> Ill cN!O O O I-' p. p. p. Cl) ............... O c:: c:: c:: p. s s s ..... c:: C" C" C" SID ..,..ID ::s () ::s C" rt Ill rt ..... 0 11 0 n ::SC"::S Ill ..... 0 ..... "" rt ::s rt C" (I) Ill (I) O rt ::s + (I) Ill rt (I) � ONNN * * * * * * � Ill C" � "" ..... (I) m � . i t::I r:s (I) rt Ill 11> rt Ill � ::T' ::t � r:s CIJ OQ CIJ (I) "ti fl> ::T' Ill l'%j CIJ 11 (I) 0 s � i ::s P.Z (I) 0 > p. Ill • 0 rt CIJ ::T' 0 11> HI fl> • " • Diets 2% NaB + 2% NaB + 2% NaHC03 2% NaHC03 1% NaB + Basal 1% NaHC03 30 32 72.3 73.2 115.5 116.6 .540 .445 .588 .630 .575 .578 2.27 2.24 3.24 3.36 2.90 3.05 420 503 534 533 504 528 w 

Zeranol and Diethylstilbestrol Implants for Feedlot Lambs

https://openprairie.sdstate.edu/cgi/viewcontent.cgi?article=1004&amp;context=sd_sheepday_1977

Zeranol and Diethylstilbestrol Implants for Feedlot Lambs

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