One way to improve rate and efficiency of lamb production is by the use of growth stimulating compounds. Resorcylic Acid Lactone (RAL) is a relatively new growth stimulating compound that has been shown to improve weight gains and feed efficiency of growing and finishing beef cattle. South Dakota researchers have reported 13% faster gains on 9.7% less feed for yearling steers implanted with 36 mg. RAL when compared to control steers. Two trials were conducted to determine if a 12 mg. implant of RAL would be effective in improving performance of young growing lambs

Bush, Leon F.

Whetzal, Frank

English

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South Dakota State UniversityOpen PRAIRIE: Open Public Research Access InstitutionalRepository and Information ExchangeSouth Dakota Sheep Field Day Research Reports,1970 Animal Science Reports1970The Effect of RAL Implants on Lamb PerformanceLeon F. BushSouth Dakota State UniversityFrank WhetzalFollow this and additional works at: http://openprairie.sdstate.edu/sd_sheepday_1970This 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 Research Reports, 1970 by an authorizedadministrator of Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. For more information, pleasecontact michael.biondo@sdstate.edu.Recommended CitationBush, Leon F. and Whetzal, Frank, "The Effect of RAL Implants on Lamb Performance" (1970). South Dakota Sheep Field Day ResearchReports, 1970. Paper 3.http://openprairie.sdstate.edu/sd_sheepday_1970/3Sou th Dakota S t ate University Brookings , South Dakota Department o f  Animal S cience Agricultural Experiment S tation A . S .  Series 69-48 The Effec t o f  RAL Implants on Lamb Performance Leon F .  Bush and Frank Whetzal One way to improve rate and efficiency of lamb production is by the use of growth s timulating compounds. Resorcylic Acid Lactone (RAL) is a relatively new growth s timulating compound that has been shown to  improve weight gains and feed efficiency of growing and f inishing beef cattle. South Dakota researchers have repor ted 13% f as ter gains on 9.7% less feed for yearling s teers implanted with 36 mg. RAL when com­pared to control s teers. Two trials were conduc ted to determine if  a 12 mg . implant of  RAL would be effec tive in improving performance of  young growing lambs. Procedure Trial 1 Two hundred nine ty-seven lambs from whi te-faced ewes o f  mixed breeding were used in thi s  trial. Either b lack-faced rams (Hampshire or Suf folk) or Columbia rams sired the lambs. At birth part of the ram lambs were treated to produce bi lateral cryptorchid ( "push-up") and the remaining ram lambs were castrated . Approximately half o f  the lambs excluding 40 replacement ewe lambs were randomly selected and implanted with 12 mg. RAL. The remaining lambs served as controls. All lambs were fed in a single group during the experiment . Feeding was done twi c daily. A mixed ration of 40% alfalfa hay , 40% s team ro lled barley and 20% whole oats was fed for the first 31 days. At this time oats was discontinued and a ration of 40% alfalfa hay and 60% s team rolled barley was fed. The lambs were marketed in two groups. At the f irs t marke ting date all lambs that weighed 90 lb. on more were sold and this included about 50% of the lambs . The lighter weight lambs were kept on feed for another 7 7  days and so ld at an average weight of about 110 lb. The replacement ewe lambs were removed from the trial before .the second group of lambs were sold . Each group of  lambs was trucked approximately 350 miles to a packing pl ant where carcass d�ta were obtained. • • .· • • • • - 2 -Trial 2 The 105 lambs used in thi s  trial were f rom ewes on a confinement rearing s tudy . White-faced wes tern ewes were mated to either Hampshire or Suffolk rams . These ewes were on three treatments (I)  conf ined to drylo t and bu ilding with s traw bedding , ( II)  confined to drylot and bu ilding with elevated slo t ted f loor , and ( III) pastured when pas ture was available then confined to drylot and building with s traw bedd ing during the winter . Lambs were born and raised in the building in their respective lo ts . Lambs were cas trated and docked before they were 10 days o f  age. Creep f eeding was s tarted when lambs were about two weeks · old . The creep ration - rolled oats , corn , soybean meal and alfalfa hay was gradually swi tched to a pelleted ration o f  70% concentrate and 30% roughage . The pelleted ratiun was self-fed . Lambs were weaned when approximately 70 days o f  age . After weaning lambs from each ewe treatment lot were divided into groups by sex and then randomly divided according to body weight into t reatment lot s  ( implanted and control ) .  The treated lambs were implanted with 12 mg . of RAL at the base of the ear . Lambs were marke ted at about 105 pounds . Carcass data were obtained on all lambs . Pelt weights and pelt pulling s cores were also obtained at time of s laughter . Results and Dis cuss ion Trial 1 The performance o f  lambs and their response to the RAL implants until the f irst group was sold (74 days)  is shown in Table 1. Average daily gain of all lambs was increased by the implants ,  however improvement in gain made by ewe lambs was rather small .  The greatest response to implants was shown by we ther lambs which gained about 3.6 lb . more per head than the controls. This is approximately a 12% increase in daily gain . Daily gain for the implanted "pushup" lambs was about 5.3% greater than for those not implanted . Lambs that were kept on feed for the entire feeding period (151 days ) had a lower rate of gain and showed less response to the implants than was shown for the firs t 74 days of  the trial (Table 2) . Indications were that the implants had los t their effectiveness before the end of the 151 day feeding period . The lowered daily gains for the longer feeding period may have resulted in part from feeding to heavier weights . Average gains made by the lambs fed for the entire period were highes t for the "pushup" lambs followed by the wethers with the ewe lambs gaining the leas t. To tal gain for lambs f ed the entire period amounted to 79 lb . for " pushups" , 72 lb . for wethers and 66 lb . for ewe lambs • - 19 -- 3 -Tab le 1 . Response of  feedlot lamb s to RAL implants (June 10 to Augus t 2 3  - 74 days ) PushuEs Treat- Im- Non-im-ment Elanted planted N o . lamb s a 25 23 Ini t.  wt . , lb • 50 . 6  5 3 . 6  Final wt . , lb .  94 . 2  95 . 0  Av . gain , lb .  43 . 6  4 1 . 4  Av . daily gain , lb . 0 . 5 9 0 . 56 Non-pushups (we thermates ) Im- Non-im-plan ted_E_J.an ted 2 3  21  49 . 7  49 . 2  88 . 7  84. 7 39 . 0  35 . 5  0 . 5 3 0 . 48 aincludes all lambs on feed Ewes Wet hers Im- Non-:-im- Im- Non- im-12lanted planted 12lante� 12lanted 44 82 31 36 48 . 0  49 . 3  5 4 . 5  54 . 6  82 . 4  83 . 2  95 . 0  91 . 3  34 . 4  33 . 9  40 . 5  36 . 7  0 . 46 0 . 46 0 . 55 0. 50 ------------------------------- · - ---- - - - - - -• Tab le 2 .  Response of  feedlot  lamb s  to RAL imp lants (June 10 to November 8 - 151 da . , Non-pushups PushuEs (we thermate s )  Treat- rm..: ment planted No . lambs a 7 !nit . wt . , lb .  39 . 3  Final wt . , lb . 118 . 9  Av . gain , lb . 7 9 . 6  Av . daily . ! gain , lb . 0 . 53 Non- im- Im- Non-im-l���pla�tetL p_liit_!ted · _ 7 10 12 40. 6 42 . 0  44 . 5  118 . 9  114 . 1  115 . 5  7 8 . 3 7 2'. 1  7 1 . 0  0. 5 2  0 . 48 0. 47  a Includes lambs remaining on trial af ter first removed . - 20 -Ewes Wet hers Im-23 38 . 7  105 . 7  67 . 0  0 . 44 Non-im- Im-l�nted ___ p l�te� . 31 8 . ... 43 _- 7  44 . 0  109 . }.  119 . 4  65 . 3  75 . 4  0 . 43 0 . 50 Non- im planted 11 40 . 7  111 . 2  7 0. 5 0 . 47 group sold and replacement ewe lambs • • • • • - ·4 -Performance of the crossbred and Columbia-s ired lambs for the 74 day feeding period is shown in Table 3. The male lambs outgained the ewe lambs by about 5 lb . per head during the period . Both the cross­bred male and ewe lambs gained somewhat fas ter than the Columbia-s ired lambs , however ,  the differences were rather small . The crossbred ewe lambs gained about 2 lb . more per head and the cros sbred male lambs about 1.5 lb . more per head than the Columb ia-s ired ewe and male lambs , respectively . A high incidence of rectal prolapses occurred during the feeding period wi th a total of 21 lambs affected . The incidence was higher in the implanted wi th 16 affected compared to only 5 nonimplanted lambs . Both ewe and we ther lambs were affected with deaths of  13 ewe and 8 male lambs . The maj ority of cases (14) occurred during the las t 3 weeks of  Augus t when the weather was hot . 1 The RAL implants appeared to have little effect upon the carcass traits s tudied (Tab le 4) . Carcass grades ranged from high good to  average choice for the fi rs L group of  lambs sold . The ewe and we ther lamb carcass grades were qu i �e similar while the "pushup" lambs graded about 1/3 grade lower . The conformation s core and carcass grades of  the crossbreds averaged about 1/3 grade higher than those o f  the Columbia-sired lamb s . The carcasses o f  the second group o f  lambs sold weighed about 10 lb • more per carcass than did those sold earl ier . The heavier carcasses graded about 1/3 grade �igher tha.n those sold firs t and ranged from low to high choice grades . The di fference in conforma tion score and carcass grade be tween the crossbred and Columb ia-sired lambs was again about 1/3 of a grade . Tab le 3. Feedlo t performance of cro ssbred and Columb ia-s ired lambs (74 days ) Crossbred Columbia-sired Crossbred Columbia-sired male lamb s  male lambs ewe lambs ewe lambs No . lambs 64 97 66 65 Initial  wt . , lb .  55.2 50.5 50.1 47.S Fianl wt . , lb .  94.B 88 . 7  84.8 80.4 Av . gain , lb .  39.6 38.2 34. 7 32.9 Av . d aily gain , lb • 0.54 0.52 0.47 0.44 - 21 -., .� J � I �-• . .. • • �able 4 .  Carcass Da ta Summary Cros sbred lamb s Pushups Ewes We thers Total RAL Cont- RAL Con:- RAL Cont- RAL Cont- RAL Cont- RAL Cont- or Treatment rol re� rol rol rol ro l average �----Marke ted a 1 1 2 r 1 1 2 2 1 1 2 2 No . lambs 6 8 1 2 13 15 13  13  18  14  6 9 120 Carcass wt . , lb .  48 . 3  46 . 0  33 . 0  62 . 5 45 . 3  43 . 2  5 1 . 3  53 . 4  47 . 3  46 . 2  59 . 8  5 8 . 9  49 . 2 Conf • s core b 20 . 5  19 . 8  18 . 0  2C . S  21 . 2 20 . S  21 . 2  22 . 2  20 . 7  20 . 5  2 1 . 8  21 . 8  2 1 . 0  Mflrb . s core 4 . 7  4 . 6  4 . 0  s .  0 4 . 8  4 . 9  4 . 9  5 . 1  4 . 9  4 . 9 5 . 2  5 . 2  4 . 9  Carcas s grade b 19 . 0  18 . 8  17 . 0  20 . 5 19 . 8  19 . 9  20 . 5  21 . 0  19 . 7  19 . 7  21 . 0  2 1 . 2 20 . Columb ia-s ired lamb s No . lamb s · 9 8 6 5 3 3 11 18 17 20 14 16 130 Carcass wt . , lb . 43 . 0  45 . 8  5 9 . 0  52 . 2  37 . 7  42 . 3  47 . 6  5 1_ .  2 42 . 9  41 . 4  5 2 . 7  50 . 3  47 . 3  1 Conf . s core 19 . 1  18 . 9  20 . 3  19 . 8  19 . 7  20 . 0  20 . 3  20 . 5  19 . 4  19 . 2  20 . 7  20 . 2  19 . 9  N II") Marb . s core 4 . 1 4 . 6  4 . 8  4 . 6  4 . 3  5 . 0  4 .  7 . 5 . 0 . 4 . 8  4 . 7  5 . 0 4 . 9 4 . 8  N 1 Carcass grade 18 . 2  18 . 5 20 . 0  19 . 4  18 . 7  19 . 7  19 . 5  20 . r  19 . 0  18 . 8  20 . 5  19 . 9  19 . 4  Sunnnary for RAL treatments No . lambs 15 16 7 7 16 18 24 · 3 3  35  34 20 25 250 Av o carc a s s  wei�ht 5 lb .  45 . 1  45 . 9  55 . 3  55 . 1  43 . 9  43 . 0  49 . 5  52 . 2  45 . 1  43 .• 4 54 . 8  53 . 4  48 . 2 Conf . s cc re 19 . 7  19 . 3  20 . 0  20 . 0  20 . 9  20 . 4 20 . 8  21 . 3  20 . 1  19 . 8  21 . 1  20 . 8  20 . 4  Marb . s core 4 . 3  4 . 6  4 . 7  4 . 7  4 . 7  4 . 9  4 . 8  5 . 0  4 . 9  4 . 7  5 . 0  5 . 0  4 . 8  Carcas s g rade 18 . 5  18 . 6  19 . 6  19 . 7  19 . 6  19 . 9  20· . o 20 . 5  19 . 4  19 . 2  20 . 6  20 . 4  19 . 7  a 1 - ind icates lambs sold a fter 74 days on feed · an� 2 - thos e lamb s marke ted 7 7  days later c b G rade and conformation s cores : 1 7  = good ; 18 = high good ; 19  = low choic� ; 20 = av . choic e ;  21  = high choice and 22 = low prime . - 6 -� Trial 2 • • Lamb performance and carcass data are shown in table 5. Lambs implanted wi th 12 mg . RAL d id not respond favorably to treatment . Rate ·of  gain was decreased and more feed was required per pound of gain for the implanted lambs than for those not implanted . The ewe lambs from the ewe pas ture t reatment lo t ( III) we·re the only group of lambs which showed an increase in growth rate as a result of RAL implant . However implanted ewe and wether lambs in ewe treatment Lot 1 gained more rapidly for the firs t 56 days on feed than did the contro l lambs • . At this time the treated lambs weighed 86 lb . and 92 lb . for ewes and wethers , respectively . The control  we ther lambs gained 0.1 lb . per day fas ter than treated wethers while there was only 0.02 lb . difference in gain in favor of  non-implanted ewe lamb s . Implanted lamb ·s-: consumed less feed per day than controls . Feed efficiency was nearly . the same for ewe lambs , however implanted wether lambs required about 0.4 lb . more feed per pound of gain than those not implanted . RAL implant did not s ignificantly effect the carcass characted � f"i  r s  s tudies . The re were only small differences found in carcass grade , fat thickness and percent loin and leg , between the implanted and non-implanted iamb s . Average loin eye area was larger for the control  lambs , however considerable variation in  LEA was observed for  all  lambs . There was no dif ference in LEA be tween ewes and wethers • The diff iculty of pelt pulling was observed and s cored . Pelts seemed to pull harder from ewe lambs than f rom we thers . An increase in dif ficulty of  pulling pelts from implanted ewe lambs was mos t  no ticeab le .  Lambs fed on slotted floor graded higher and were fat ter than those fed on s traw bedding . The ewe lambs had more fat thicknes s than the des irab le maximum o f  Q • . 3 inch . Feed intake for ewes on s lats was greater and they were les s  efficient than ewes on s t raw . Wether lambs on slotted flooi; consumed. somewhat les s  feed and were more ef f icient than wethers raised on s traw bedding . Rate of gain , and feed efficiency were decidedly in f avor o f  wether lambs fed on s lo t ted f loor • - 23 -.. .  1• • - 7 -Tab le 5 .  Response of Lambs Implanted with RAL Ewe Treatm_ent�· __ No . lambs group Ini t i a l  wt � , lb . Final wt . , lb . Rate o f  gain/ day Av . days on feed Feed intake/day Feed req . /lb . gain No . rec tal : prolapse Ca r c a s s  grade Fat thickness LEA s q . in .  % loin and leg Pel t wt . , Ib .  Pelt pulling s core! No . lambs /group grou� Ini t ial wt . , lb .  Final wt . , lb . Rate of gain/ day Av . days on feed Feed intake/ day Feed req . /lb . gain No . rec tal prolapse Ca rcass grade Fat thickne s s  LEA sq . in .  % loin and leg Pelt wt . , lb . Pelt pulling s core1 Pas ture S traw .Weth_�e Wetber Implanted 9 10 10 9 53 . 9  55 . 3  54 . 5  60 . 0  103 . 6  104 . 2  110 . 2  107 . 0  0 . 48 0 . 39 0 . 5 2 0 . 48 102 . 0  · 103 . 8 105 . 0  97 � 8  ' 3 . 76 3 . 44 3 . '5 9  3 . 5 4 7 . 83 7 . 7 2 6 .  97 . 7 . 37 0 0 1 . 0  0 ch ch ch+ ch 0 . 26 0 . 23 0 . 35 0 . 24 2 . 00 l .' 90  2 . 26 2 . 06 48 . 1  4 7 . 5  45 . 8  48 . 4  13 . 8  14 . 7  12 . 6  13 . 0  3 . 43 2 . 7 5 3 . 00 2 . 88 Cont ro l 11 6 8 11 56 . 1  5 6.0 5 1 . 2  55 .. 6 104 . 1  107 . 0  109 . 1  106 . 3  0 . 43 0 . 55 0 . 56 0 . 5 2 111 . 0 92 . 3  9 9 . 0  9 8 . 2 3 . 30 4 . 23 4 . 2 1 3 . 19 7 . 6 2 7 . 66 7 . 48 6.18 0 1 . 0 1 . 0 0 ch ch ch+ ch 0 . 27 0 . 31 0 . 27 0 . 27 2 . 23 2 . 2 4 2 . 3 1 2 . 21 43 . 9  46.8 48 . 1  46 . 7  14 . 5  13.0 14.7 13 . 5  2 . 60 2 . 67 3 . 00 2 . 5 6 (Brookings)  Slats Ewe We th er 7 9 · 5 6 . 3  58 . 9  103 . 0  108.1 0 . 49 0 . 54 96 . 0  88 . 4  3 . 92 3 . 10 8 . 06 5 . 69 0 0 ch+ ch+ 0 . 36 0 . 28 1 . 93 . 2 . 16 46 .- 5  45 . 8  . ·12 . 7 13 . 1  3 . 43 3 . 00 7 8 55 . 9  6 2 . 1  105 . 3  112 . 4  0 . 54 0 . 63 9 2  .. 0 7 9 . S  4 . 26 3 .  7 2  7 . 94 5.88 0 1 . 0  ch+ ch+ 0 . 38 0 . 3 2 2 . 06 2 . 20 47 . 0  45 . 9  13 . 4  12 . 5  2 . 7 5 3 . 00 1 - s co re from 1 to 5 ,  5 being the most d if f i cult - 2 4 -· • Ave • F,wp Wetbex: 26 28 54 . 9  58 . 1  105 . 6  106 . 4  0 . 49 0 . 47 101 . 0  96 . 7  3 . 7 6 3 . 36 7 . 62 6 . 9 3  1 . 0  0 ch+ ch 0 . 3 2 - -�·o .  25 2 . 06 2 . 04 46 . 7  46 . 6  13 . 0  13 . 6  3 . 29 2 . 88 • 26 25 54 . 4  5 7 . 9  . 106 . 2 108 . 6  0 . 51 0 . 57 100 . 7  90 . 0  3 . 92 3 .  7 1  7.68 6 . 57 1 . 0  2 . 0  ch+ ch 0 . 31 0 . 30 2 . 20 2 . 22 46 . 2  46 . 4  14 . 2 13 . 0  2.7 8  2 . 7 4 • • •. • l • - 8 -_Sunnnary In almos t every respect lambs in trial 1 (Newell) and in trial 2 (Brookings)  responded converse ly to a 1 2  mg . implant of  RAL (resorcyclic acid lactone ) . Wether lambs in trial 1 gained 12% fas ter while wether lambs in trial 2 gained about 17% s lower than the controls . Ewe lambs were affec ted to a les ser extent but in the same manner .  Daily gain for the implanter "push-up" lambs was about 5 . 3% greater than those not implanted . In trial 1 ,  inc idence o f  rectal prolapse was affected by implants ( 16 vs . 6 cases for implant and control , respec t ively) . A few rec tal prolapses were observed in trial 2 ;  however , they were not related to RAL treatment . : :The implants had lit tle effec t on carcass t raits s tudied in this experitnent . Diff iculty of  pulling pelts was observed and s cored in trial 2 .  Removal of the pelt from implanted . .1,ambs was more diff icul t than for control lambs . The increased difficulty was espe c i a lly no ted in implanted ewe lambs • - 2 5  -

The Effect of RAL Implants on Lamb Performance

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The Effect of RAL Implants on Lamb Performance

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