- Email: [email protected]
Association of Implanting Abnormalities with Growth Performance of Feedlot Steers
128
Berry et Scientist al. The Professional Animal 16:128–133
of Implanting Association Abnormalities with Growth Performance of Feedlot Steers B. A. BERRY*,1, PAS, L. J. PERINO*, M. L. GALYEAN*,3, PAS, T. H. MONTGOMERY*, and S. BACHMAN*,4 *West Texas A&M University, Division of Agriculture, Canyon, TX 79016
Abstract
initial BW, reimplant BW, pen, health status, liver status, lung status, and implant status as covariates. Average daily gain for the initial period did not differ (P>0.40) across implant status. In the overall model, there was a trend (P<0.10) for d 60 to harvest ADG to be affected by implant status. In pair-wise least square means comparisons of implant defects, only missing implants, compared with normal implants or abscessed implants, showed less gain (P<0.05) in both laboratory and packing plant palpation models.
control programs (5). It is believed these defects cause decreased perforCrossbred steers (n = 1, 183, mean mance. However, no data exist initial BW = 320 ± 33 kg) were used in quantifying effects of these problems an observational study to determine on ADG and feed efficiency. associations between implanting abnorThere are implanting quality malities and feedlot growth performance. control practices in place in most Initial implant status (determined by feedlots. Implanting quality control palpation) was recorded during adminisprograms conducted in the feedlot tration of a terminal implant. Status of generally involve removing a portion the terminal implant was recorded 21 d of the cattle from the pen after a set after reimplant, post-mortem in a time following implantation to packing plant, and post-mortem in a palpate the implant site. Although laboratory. At each of the four examinathis facilitates proper implanting tions, implants were classified by technique, these programs create a palpation as either: 1) normal, 2) (Key Words: Implants, Abnormalities, dilemma for most feedlot managers, abscessed, 3) bunched pellets, 4) sepaGrowth Performance, Feedlot Steers.) because cattle performance likely rated pellets, 5) partial retention, 6) total suffers from the extra handling and failed retention, 7) placed in the cartitime away from the pen. Some lage, 8) placed in the inner 1/3 of the quality control programs involve Hormonal growth-promoting ear, or 9) fluid-filled. Least square palpating implant sites at the time of implants increase ADG and improve means for ADG were determined for slaughter (3), which allows feedback both the initial period (d 0 to 59) and the feed efficiency of beef cattle (2). regarding the quality of the implant Proper implanting technique and a terminal period (d 60 to harvest) using program without disturbing the strong quality control program are animal; however, these programs do generally considered vital componot allow the producer to detect any nents of a successful implanting problems that might arise in real program. An observational study time. 1Present address: Dept. of Anim. Sci., Oklaconducted in several High Plains One of the objectives of the present homa State Univ., Stillwater, OK 74078. feedlots during the late 1980s revealed study was to characterize the agree2 To whom correspondence should be ad- that 33.7% of the animals observed ment of quality control checks dressed: [email protected] had some type of problem with their performed at different times and 3Present address: Dept. of Anim. Sci. and Food implant (4). More recently, manufac- settings. A second objective was to Tech., Texas Tech Univ., Lubbock, TX 79409. turer surveys have revealed problem determine the association between 4 Armbruster Consulting, Amarillo, TX 79109. rates from 3 to 33% in feedlots with implanting abnormalities and feedlot employee education and quality performance.
Introduction
Implanting Abnormalities in Feedlot Steers
TABLE 1. Average daily gain by implant status of the terminal implant (chain-speed palpations) for d 60 to slaughter. Initial wta Status
Reimplant wta Hot carcass wta
ADGa
n
Mean
SEM
Mean
SEM
Mean
SEM
Mean
SEM
Normal 741 Abscessed 46 Bunched 21 Separated 45 Partial 67 Missing 73 Cartilageb 15 Inner one-third 37 Fluid-filledb 9
320.2 316.0 325.2 318.2 322.1 321.6 339.5 317.8 316.3
33.9 28.2 31.4 33.4 33.7 32.7 37.0 34.1 20.4
452.8 445.6 465.6 455.0 457.8 451.2 454.0 451.3 454.2
(kg) 41.0 38.1 48.9 40.4 41.9 44.4 42.1 41.4 33.7
360.6 358.3 360.3 358.3 354.3 354.5 347.6 363.9 351.3
38.3 37.2 51.5 35.1 34.7 41.5 44.6 40.4 30.4
1.34c 1.39c 1.25cd 1.27cd 1.28cd 1.23d – 1.36cd –
0.01 0.05 0.08 0.05 0.04 0.04 – 0.06 –
aLeast
squares means (SAS, 1990). removed from analysis. c,dMeans in a column with different superscripts are different (P<0.05). bStatus
Materials and Methods Animal Description. Crossbred steers (n = 1, 183, mean BW 320 ± 33 kg) of Southwestern origin (two states and three sources) were used in this observational implant study in one feedlot in the Oklahoma Panhandle. The feedlot received the steers in late February from three sources and sorted them into five
pens according to source (three pens from one source and two pens with one source each). Two pens housed 250 animals, and the other three pens housed 300, 251, and 132 animals. After arrival at the feedlot, all animals remained in receiving pens until processing 2 to 6 d later, when the study began. The first pen of steers was vaccinated, dewormed, implanted, and
TABLE 2. Average daily gain by implant status of the terminal implant (laboratory palpations) for d 60 to slaughter. Initial wta Status
Reimplant wta Hot carcass wta
ADGa
n
Mean
SEM
Mean
SEM
Mean
SEM
Mean
SEM
Normal 628 Abscessed 21 Bunched 21 Separated 12 Partial 49 Missing 22 Cartilageb 1 Inner one-third 18 Fluid-filledb 1
318.7 316.0 314.7 326.7 324.1 316.9 313.9 309.8 305.3
32.0 37.1 30.8 36.2 35.9 29.8 – 30.0 –
456.2 456.6 454.2 464.2 462.7 442.3 492.2 440.8 402.8
(kg) 40.6 41.1 50.5 47.9 42.7 37.3 – 28.4 –
369.8 371.2 373.7 371.2 372.0 352.0 352.9 356.7 344.7
34.7 30.6 44.6 28.3 36.5 31.5 – 28.3 –
1.37c 1.36c 1.42c 1.34cd 1.32c 1.15d – 1.27cd –
0.01 0.07 0.07 0.10 0.05 0.07 – 0.08 –
aLeast
squares means (SAS, 1990). removed from analysis. c,dMeans in a column with different superscripts are different (P<0.05). bStatus
129
weighed in the feedlot’s hospital, using a hydraulic squeeze chute to restrain animals during vaccination, deworming, and implanting. A manual chute equipped with scales was used to obtain individual BW. All other pens were vaccinated and dewormed in the processing barn and, within the same day, implanted and weighed at the hospital. All animals received an implant without regard to any previous implants that might have been present. The processing crew administered a modified live-virus vaccine (Bovishield® 4; Pfizer, Exton, PA) against infectious bovine rhinotracheitis virus (IBR), bovine viral diarrhea virus (BVD), parainfluenza type-3 virus (PI3), and bovine respiratory syncytial virus (BRS) to all animals. All steers received an antiparasitic compound (Dectomax®; Pfizer, Exton, PA) to control endoand ectoparasites. A modified livevirus vaccine (Bovishield® 3; Pfizer, Exton, PA) against IBR, BVD, and PI3 was administered at reimplant time, approximately 60 d later. All animals were stepped up to a final steamflaked corn- and silage-based diet typical of diets fed in High Plains feedlots. Implant Administration. Either the implanter from the processing crew or an available member of the pen-rider crew administered the implants as was typically done by the feedlot. The experimenters offered no suggestions, and merely observed the administration of the implants. Steers were initially given a combination estadiol benzoate (20 mg, 14 E2) and progesterone (200 mg) implant (Synovex® S; Fort Dodge Animal Health, Overland Park, KS) during initial processing, followed by a combination estradiol (24 mg) and trenbolone acetate (120 mg) implant (Revalor® S; Hoechst-Roussel Agri-Vet Co., Somerville, NJ) in the opposite ear after approximately 60 d on feed. Feedlot Data. One person conducted all ear palpations in the feedlot. Implant sites were scored as: correct, implant site abscessed, pellets bunched, pellets separated, missing a
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Berry et al.
TABLE 3. Average daily gain by implant status of the terminal implant (3-wk palpations) for d 60 to slaughter. Initial wta Status
Reimplant wta Hot carcass wta
ADGa
n
Mean
SEM
Mean
SEM
Mean
SEM
Mean
SEM
Normal 837 Abscessed 16 Bunched 5 Separated 26 Partial 68 Missing 39 16 Cartilageb Inner one-third 19 Fluid-filledb 18
319.6 308.2 328.4 324.5 325.5 329.9 313.1 317.5 327.7
33.5 23.1 29.0 41.6 37.9 28.6 30.5 23.7 27.3
452.7 433.2 453.1 457.0 458.1 460.0 435.4 448.3 459.0
(kg) 41.0 23.7 36.3 51.5 44.7 35.0 39.9 36.3 42.7
360.0 343.9 352.8 361.5 361.7 361.8 328.8 362.2 359.3
37.9 25.5 45.6 42.1 39.6 36.0 35.8 44.1 48.1
1.34 1.45 – 1.24 1.33 1.22 – 1.42 –
0.01 0.09 – 0.07 0.04 0.06 – 0.08 –
aLeast squares means (SAS, 1990). bStatus removed from analysis.
portion of the pellets, missing the entire implant, placed in the cartilage of the ear, placed in the inner 1/3 of the ear, or implant site fluid-filled. Implants were scored as is typical for manufacturer’s quality control tests. Palpations were conducted on the initial implant at approximately d 60 (reimplant), and on the terminal implant approximately 3 wk after its administration, at harvest, and in the laboratory following harvest. At reimplant, BW was obtained on a hydraulic scale suspended using a
two-point load cell system. Both scales were calibrated to be accurate within 0.9 kg. Buller steers were housed in a buller pen following diagnosis. Animals diagnosed with respiratory disease were treated as was typical for the feedlot. Cattle sold early, cattle that died, and bullers were not available for implant site evaluation, and thus were not included in the data. Slaughter Plant Data. All cattle were fed to an endpoint as deter-
TABLE 4. Average daily gain by implant status of the initial implant for 0 to 60 d. Initial wta Status
Normal Abscessed Bunched Separated Partial Missing Cartilage Inner one-third Fluid-filled aLeast
Reimplant wta
ADGa
n
Mean
SEM
Mean
SEM
Mean
SEM
619 44 21 62 75 79 49 79 65
320.9 314.0 315.1 321.8 321.1 315.0 312.9 323.2 324.5
34.5 33.1 37.0 30.8 31.7 30.6 29.5 35.0 33.0
(kg) 454.3 449.4 440.4 453.5 450.8 450.7 446.0 453.8 455.3
42.9 41.8 37.0 38.0 39.2 38.3 32.7 41.4 42.6
2.14 2.22 2.05 2.20 2.13 2.18 2.15 2.09 2.11
0.02 0.05 0.08 0.05 0.04 0.04 0.05 0.04 0.05
squares means (SAS, 1990).
mined by feedlot personnel, and harvested by pen. The pens of cattle were harvested after 124, 143, 145, 161, and 166 d on feed as they became ready. The same person who palpated implants in the live animals palpated ears in the packing plant using the scoring system described previously. Slaughter plant palpations were conducted 64, 85, 80, 97, and 105 d post-reimplanting, respectively. Ears were palpated at chain speed, and only the terminal implant was checked. Trained individuals observed livers, lungs, and carcass trim. Carcass trim was recorded on the chain after the carcass had passed the hot scale. An estimate of trim was made, and any trim >4.5 kg was estimated to the nearest 4.5 kg. The hot weight of each carcass was recorded, adjusted for trim, and divided by the pen dressing percent to calculate final live weight. The above slaughter plant data were collected on all five pens. Laboratory Data Collection. Plant personnel removed ears from steers at the packing plant for four of the five pens, placing each set of ears in individual bags to retain identity. The ears were then transported to the laboratory. The terminal implant for each animal was repalpated in the laboratory to evaluate the agreement between the laboratory palpation and chain-speed palpation. When necessary, the ear was dissected to confirm classification, and the palpater was blind to previous ear scores. Statistical Analyses. A clinically significant threshold of a 5% decrease in ADG as a result of implant abnormalities was assumed. Using a standard deviation of 0.11 kg, it was determined that to detect significant differences in ADG, the sample needed to include 34 abnormalities. Contact with implant manufacturer representatives who conduct quality control palpations in feedlots revealed that the smallest abnormality incidence rate expected would be from 3 to 5%. Hence, it was estimated that 1000 to 1200 animals were needed to detect a
131
Implanting Abnormalities in Feedlot Steers
clinically significant effect on ADG (6). A kappa statistic (6) was used to determine the degree of agreement between palpations conducted approximately 3 wk after the terminal implant was administered, and those conducted at the time of harvest. Kappa also was used to determine the agreement of implant palpations conducted in the laboratory with implant palpations conducted at chain speed. The kappa statistic is a measure of agreement between two diagnostic tests adjusted for agreement resulting from chance. Scores can vary between 0 and 1, with values of 1 indicating perfect agreement, values greater than 0.75 representing excellent agreement beyond chance, values between 0.40 and 0.75 representing fair-to-good agreement beyond chance, values below 0.40 indicating poor agreement beyond chance, and values of zero indicating no agreement (6). To analyze the relationships between performance and implant defects, the SAS General Linear Models procedure (7) was used to develop a model and evaluate the implant status on ADG. Models were initially created controlling for pen, initial BW, reimplant BW, carcass trim, and the hospital treatments the animal received. Reimplant BW and trim evaluations were dropped from the initial feeding period model (d 0 to 59), and initial BW was dropped from the 3-wk, chain-speed, and laboratory models (d 60 to slaughter).
Results and Discussion Performance by Cattle with Abnormal Implants. In the overall model, there was a trend for ADG from d 60 to harvest to be affected (P<0.10) by implant defects. These data agree with Nebraska researchers (1), who found that an overall abnormal implant status resulted in 0.06 kg (P<0.01) loss in ADG. The overall model included six (normal, abscessed, bunched, separated, partial, missing, and inner 1/3) of the eight initial categories for both types
TABLE 5. Agreement of implanting abnormality palpations between the classification of implant defects of the terminal implant in the laboratorya and in the slaughter plantb (n = 785). Slaughter plant palpations Laboratory palpations Normal Abscessed Bunched Separated Partial Missing Inner one-third
Inner Normal Abscessed Bunched Separated Partial Missing one-third 509c 3 10 7 17 3 10
10 16d 4 0 0 0 0
11 1 4e 0 1 0 0
25 1 1 3f 3 1 0
22 1 2 2 15g 1 1
28 0 0 2 14 25h 3
22 0 0 0 0 2 5i
aPalpation
performed in laboratory setting with no time constraint. performed in slaughter facility at chain speed (6 to 8 s per animal). cFair to good agreement beyond chance (K = 0.43). dFair to good agreement beyond chance (K = 0.60). ePoor to fair agreement beyond chance (K = 0.19). fPoor to fair agreement beyond chance (K = 0.10). gPoor to fair agreement beyond chance (K = 0.28). hFair to good agreement beyond chance (K = 0.45). iPoor to fair agreement beyond chance (K = 0.18). bPalpation
TABLE 6. Agreement of implanting abnormality palpations between the classification of implant defects of the terminal implant in the feedlota and in the laboratoryb (n = 772). Laboratory palpations Feedlot palpations
Normal Abscessed Bunched Separated Partial Missing Inner one-third aPalpation
Inner Normal Abscessed Bunched Separated Partial Missing one-third
573c 2 1 17 23 4 9
10 5d 2 0 2 2 0
10 0 1e 1 5 2 0
8 0 0 0f 2 2 0
20 0 0 1 18g 10 0
7 1 0 1 0 13h 2
performed in the squeeze chute 3 wk after reimplant with no time constraint. bPalpation performed in laboratory setting with no time constraint. cFair to good agreement beyond chance (K = 0.46). dPoor to fair agreement beyond chance (K = 0.32). ePoor to fair agreement beyond chance (K = 0.08). fNo agreement beyond chance (K = –0.02). gPoor to fair agreement beyond chance (K = 0.32). hFair to good agreement beyond chance (K = 0.44). iPoor to fair agreement beyond chance (K = 0.17).
12 1 0 1 1 0 3i
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Berry et al.
TABLE 7. Agreement of implanting abnormality palpations between the classification of implant defects of the terminal implant in the feedlota and in the slaughter plantb (n = 1004). Slaughter plant palpations Laboratory palpations
Inner Normal Abscessed Bunched Separated Partial Missing one-third
Normal 673c Abscessed 3 Bunched 0 Separated 17 Partial 19 Missing 5 Inner one-third 7
18 11d 1 0 3 4 2
16 0 1e 1 3 0 1
27 0 0 5f 10 2 0
36 0 2 1 22g 5 1
31 2 0 0 10 26h 3
29 0 0 1 0 1 5i
aPalpation
performed in the squeeze chute 3 wk after reimplant with no time constraint. performed in slaughter facility at chain speed (6 to 8 s per animal). cFair to good agreement beyond chance (K = 0.42). dPoor to fair agreement beyond chance (K = 0.39). ePoor to fair agreement beyond chance (K = 0.07). fPoor to fair agreement beyond chance (K = 0.12). gPoor to fair agreement beyond chance (K = 0.28). hFair to good agreement beyond chance (K = 0.42). iPoor to fair agreement beyond chance (K = 0.16). bPalpation
of harvest palpations (chain-speed and laboratory). In a pair-wise least square means comparison of implant defects (Tables 1 and 2), only missing implants compared with normal implants or abscessed implant sites showed less (P<0.05) gain in both harvest palpation models. Cattle with missing implants also showed decreased (P<0.05) ADG in the laboratory palpation model, compared with cattle with bunched pellets and only partial retention of pellets (Table 2). Implant palpations conducted on the terminal implant shortly after implanting (Table 3) were not significant (P>0.10) in the overall ADG d 60 to harvest model. Palpations performed on the initial implant (Table 4) showed no effect (P>0.40) on ADG from d 0 to reimplant. However, failure to demonstrate a difference may have resulted from high variation in ADG during that period. Additional experimental error could have been introduced by cattle entering the study with an undetermined implant status. These data were unobtainable because of re-
straints placed on this study because of its commercial setting. These data suggest that quality control programs have the potential to contribute to a successful implant program. Implant sites that failed to retain the product, measured at harvest either in the laboratory or at chain-speed, resulted in a significant loss of ADG. Our findings suggest that, rather than focusing on the entire array of abnormalities that occur in implants, attention should be devoted to increasing the rate of retention in implant sites. Cattle with abscessed implant sites did not perform worse than cattle with normal implant sites; however, abscesses should be minimized to avoid expulsion of the product. Surface area-altering abnormalities (e.g. bunched pellets, separated pellets) showed no effect on ADG, suggesting that rate of release of the active ingredient into the animal’s blood stream might not be affected by surface area-altering abnormalities, or that rate of release might not alter ultimate performance.
Diagnostic Test of Palpations. Overall kappa scores comparing palpations conducted shortly after implanting and palpation scores conducted at harvest (chain-speed) showed poor agreement beyond chance (kappa = 0.34). However, agreement beyond chance for implant sites determined to be normal in individual comparisons (Table 5) showed fair-to-good agreement (kappa = 0.42), and sites that failed to retain the product showed fair-togood agreement (kappa = 0.42). Overall kappa scores comparing palpations conducted approximately 3 wk post-implanting and laboratory palpations were also low (kappa = 0.35). In individual comparisons (Table 6), scores for missing implants had fair-to-good agreement beyond chance (kappa = 0.44), as did scores for normal implant sites (kappa = 0.46). Overall agreement beyond chance of the two harvest palpations, chainspeed and laboratory, was low (kappa = 0.37). Abscessed implant sites (kappa = 0.60), normal implant sites (kappa = 0.43), and sites that failed to retain the implant (kappa = 0.45) showed fair-to-good agreement beyond chance in individual comparisons (Table 7). All other defect categories had low agreement beyond chance. Outcomes of diagnostic tests comparing harvest palpations to palpations conducted shortly after implanting indicate that 3-wk checks might not be indicative of the final status of the implant, because of changes in the implant site caused either by absorption of the product or by progression of the infection process. One problem associated with performing all palpations at harvest is the long period of time implanters must wait before receiving feedback on their implant program. Harvest palpations would, however, cause less stress on animals, presumably facilitating increased performance. Variability from one implant check to another also must be accounted for when considering the usefulness of quality control pro-
Implanting Abnormalities in Feedlot Steers
grams. Kappa scores for palpations conducted on the same implant sites (laboratory and chain-speed) postmortem showed low agreement beyond chance for most defects. Nonetheless, for missing implants, the one defect that significantly affected ADG in our study, agreement beyond chance was fair-to-good. This result suggests that the objective of finding agreement between implant checks for all implanting abnormalities in this study was too broad, and further research should be conducted that focuses on single defects or smaller groups of defects. Another possible limitation of the study as it was conducted was the low frequency of certain defects (fluidfilled and implants placed in the cartilage), resulting in very little chance of finding significance for these defects.
133
Implications Cattle with implant sites that failed to retain the implant showed decreased ADG during the reimplant period. The ADG of cattle with other implanting abnormalities (e.g., abscesses, bunched pellets, separated pellets, partial retention, and poor placement) generally did not differ from ADG of cattle with normal implants. These findings suggest that further research should be conducted to explore methods of improving implant retention. Abnormalities found in the initial implanting had no effect on ADG from d 0 to 59, which may be attributable to high variation in ADG during that period. There also might be less effect resulting from the implant’s ability to extend cattle’s growth curve in the final period than in the differences in the growth curve before d 60. Further research should be conducted to compare the effects of abnormal implantings on ADG of cattle implanted early vs late in the feeding period.
Literature Cited 1. Bryant, L. K., L. J. Perino, D. D. Griffin, A. R. Doster, and T. E. Wittum. 1999. A method for recording pulmonary lesions of beef calves at slaughter, and the association of lesions with average daily gain. The Bovine Practitioner. 33 (2):163. 2. Duckett, S. K., F. N. Owens, and J. G. Andrae. 1997. Effects of implants on performance and carcass traits of feedlot steers and heifers. Symp.: Impact of Implants on Performance and Carcass Value of Beef Cattle. p 63. Okla. Agric. Exp. Stn., P-957. 3. Griffin, D., and L. Perino. 1992. Disease monitoring in packing houses. Proc. of the Seventeenth World Buiatrics Congress and Twenty-Fifth American Bovine Practitioners Conference, vol. 2. p 343. August 31 to September 4, 1992. St. Paul MN. 4. Hollis, L. C. 1989. Proper management of implant technique in feedlot cattle. Compend. Contin. Educ. Prac. Vet. 11:763. 5. Lehman, F. L. 1995. Technical Bulletin 14A. Hoechst-Roussel Agri-Vet Co., Somerville, NJ. 6. Martin, S. W., A. H. Meek, and P. Willeberg. 1987. Veterinary Epidemiology. Iowa State University Press, Ames, IA. 7. SAS. 1990. SAS/STAT® User’s Guide: Statistics (Release 6.04 Ed.). SAS Inst. Inc., Cary, NC.
Berry et Scientist al. The Professional Animal 16:128–133
of Implanting Association Abnormalities with Growth Performance of Feedlot Steers B. A. BERRY*,1, PAS, L. J. PERINO*, M. L. GALYEAN*,3, PAS, T. H. MONTGOMERY*, and S. BACHMAN*,4 *West Texas A&M University, Division of Agriculture, Canyon, TX 79016
Abstract
initial BW, reimplant BW, pen, health status, liver status, lung status, and implant status as covariates. Average daily gain for the initial period did not differ (P>0.40) across implant status. In the overall model, there was a trend (P<0.10) for d 60 to harvest ADG to be affected by implant status. In pair-wise least square means comparisons of implant defects, only missing implants, compared with normal implants or abscessed implants, showed less gain (P<0.05) in both laboratory and packing plant palpation models.
control programs (5). It is believed these defects cause decreased perforCrossbred steers (n = 1, 183, mean mance. However, no data exist initial BW = 320 ± 33 kg) were used in quantifying effects of these problems an observational study to determine on ADG and feed efficiency. associations between implanting abnorThere are implanting quality malities and feedlot growth performance. control practices in place in most Initial implant status (determined by feedlots. Implanting quality control palpation) was recorded during adminisprograms conducted in the feedlot tration of a terminal implant. Status of generally involve removing a portion the terminal implant was recorded 21 d of the cattle from the pen after a set after reimplant, post-mortem in a time following implantation to packing plant, and post-mortem in a palpate the implant site. Although laboratory. At each of the four examinathis facilitates proper implanting tions, implants were classified by technique, these programs create a palpation as either: 1) normal, 2) (Key Words: Implants, Abnormalities, dilemma for most feedlot managers, abscessed, 3) bunched pellets, 4) sepaGrowth Performance, Feedlot Steers.) because cattle performance likely rated pellets, 5) partial retention, 6) total suffers from the extra handling and failed retention, 7) placed in the cartitime away from the pen. Some lage, 8) placed in the inner 1/3 of the quality control programs involve Hormonal growth-promoting ear, or 9) fluid-filled. Least square palpating implant sites at the time of implants increase ADG and improve means for ADG were determined for slaughter (3), which allows feedback both the initial period (d 0 to 59) and the feed efficiency of beef cattle (2). regarding the quality of the implant Proper implanting technique and a terminal period (d 60 to harvest) using program without disturbing the strong quality control program are animal; however, these programs do generally considered vital componot allow the producer to detect any nents of a successful implanting problems that might arise in real program. An observational study time. 1Present address: Dept. of Anim. Sci., Oklaconducted in several High Plains One of the objectives of the present homa State Univ., Stillwater, OK 74078. feedlots during the late 1980s revealed study was to characterize the agree2 To whom correspondence should be ad- that 33.7% of the animals observed ment of quality control checks dressed: [email protected] had some type of problem with their performed at different times and 3Present address: Dept. of Anim. Sci. and Food implant (4). More recently, manufac- settings. A second objective was to Tech., Texas Tech Univ., Lubbock, TX 79409. turer surveys have revealed problem determine the association between 4 Armbruster Consulting, Amarillo, TX 79109. rates from 3 to 33% in feedlots with implanting abnormalities and feedlot employee education and quality performance.
Introduction
Implanting Abnormalities in Feedlot Steers
TABLE 1. Average daily gain by implant status of the terminal implant (chain-speed palpations) for d 60 to slaughter. Initial wta Status
Reimplant wta Hot carcass wta
ADGa
n
Mean
SEM
Mean
SEM
Mean
SEM
Mean
SEM
Normal 741 Abscessed 46 Bunched 21 Separated 45 Partial 67 Missing 73 Cartilageb 15 Inner one-third 37 Fluid-filledb 9
320.2 316.0 325.2 318.2 322.1 321.6 339.5 317.8 316.3
33.9 28.2 31.4 33.4 33.7 32.7 37.0 34.1 20.4
452.8 445.6 465.6 455.0 457.8 451.2 454.0 451.3 454.2
(kg) 41.0 38.1 48.9 40.4 41.9 44.4 42.1 41.4 33.7
360.6 358.3 360.3 358.3 354.3 354.5 347.6 363.9 351.3
38.3 37.2 51.5 35.1 34.7 41.5 44.6 40.4 30.4
1.34c 1.39c 1.25cd 1.27cd 1.28cd 1.23d – 1.36cd –
0.01 0.05 0.08 0.05 0.04 0.04 – 0.06 –
aLeast
squares means (SAS, 1990). removed from analysis. c,dMeans in a column with different superscripts are different (P<0.05). bStatus
Materials and Methods Animal Description. Crossbred steers (n = 1, 183, mean BW 320 ± 33 kg) of Southwestern origin (two states and three sources) were used in this observational implant study in one feedlot in the Oklahoma Panhandle. The feedlot received the steers in late February from three sources and sorted them into five
pens according to source (three pens from one source and two pens with one source each). Two pens housed 250 animals, and the other three pens housed 300, 251, and 132 animals. After arrival at the feedlot, all animals remained in receiving pens until processing 2 to 6 d later, when the study began. The first pen of steers was vaccinated, dewormed, implanted, and
TABLE 2. Average daily gain by implant status of the terminal implant (laboratory palpations) for d 60 to slaughter. Initial wta Status
Reimplant wta Hot carcass wta
ADGa
n
Mean
SEM
Mean
SEM
Mean
SEM
Mean
SEM
Normal 628 Abscessed 21 Bunched 21 Separated 12 Partial 49 Missing 22 Cartilageb 1 Inner one-third 18 Fluid-filledb 1
318.7 316.0 314.7 326.7 324.1 316.9 313.9 309.8 305.3
32.0 37.1 30.8 36.2 35.9 29.8 – 30.0 –
456.2 456.6 454.2 464.2 462.7 442.3 492.2 440.8 402.8
(kg) 40.6 41.1 50.5 47.9 42.7 37.3 – 28.4 –
369.8 371.2 373.7 371.2 372.0 352.0 352.9 356.7 344.7
34.7 30.6 44.6 28.3 36.5 31.5 – 28.3 –
1.37c 1.36c 1.42c 1.34cd 1.32c 1.15d – 1.27cd –
0.01 0.07 0.07 0.10 0.05 0.07 – 0.08 –
aLeast
squares means (SAS, 1990). removed from analysis. c,dMeans in a column with different superscripts are different (P<0.05). bStatus
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weighed in the feedlot’s hospital, using a hydraulic squeeze chute to restrain animals during vaccination, deworming, and implanting. A manual chute equipped with scales was used to obtain individual BW. All other pens were vaccinated and dewormed in the processing barn and, within the same day, implanted and weighed at the hospital. All animals received an implant without regard to any previous implants that might have been present. The processing crew administered a modified live-virus vaccine (Bovishield® 4; Pfizer, Exton, PA) against infectious bovine rhinotracheitis virus (IBR), bovine viral diarrhea virus (BVD), parainfluenza type-3 virus (PI3), and bovine respiratory syncytial virus (BRS) to all animals. All steers received an antiparasitic compound (Dectomax®; Pfizer, Exton, PA) to control endoand ectoparasites. A modified livevirus vaccine (Bovishield® 3; Pfizer, Exton, PA) against IBR, BVD, and PI3 was administered at reimplant time, approximately 60 d later. All animals were stepped up to a final steamflaked corn- and silage-based diet typical of diets fed in High Plains feedlots. Implant Administration. Either the implanter from the processing crew or an available member of the pen-rider crew administered the implants as was typically done by the feedlot. The experimenters offered no suggestions, and merely observed the administration of the implants. Steers were initially given a combination estadiol benzoate (20 mg, 14 E2) and progesterone (200 mg) implant (Synovex® S; Fort Dodge Animal Health, Overland Park, KS) during initial processing, followed by a combination estradiol (24 mg) and trenbolone acetate (120 mg) implant (Revalor® S; Hoechst-Roussel Agri-Vet Co., Somerville, NJ) in the opposite ear after approximately 60 d on feed. Feedlot Data. One person conducted all ear palpations in the feedlot. Implant sites were scored as: correct, implant site abscessed, pellets bunched, pellets separated, missing a
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TABLE 3. Average daily gain by implant status of the terminal implant (3-wk palpations) for d 60 to slaughter. Initial wta Status
Reimplant wta Hot carcass wta
ADGa
n
Mean
SEM
Mean
SEM
Mean
SEM
Mean
SEM
Normal 837 Abscessed 16 Bunched 5 Separated 26 Partial 68 Missing 39 16 Cartilageb Inner one-third 19 Fluid-filledb 18
319.6 308.2 328.4 324.5 325.5 329.9 313.1 317.5 327.7
33.5 23.1 29.0 41.6 37.9 28.6 30.5 23.7 27.3
452.7 433.2 453.1 457.0 458.1 460.0 435.4 448.3 459.0
(kg) 41.0 23.7 36.3 51.5 44.7 35.0 39.9 36.3 42.7
360.0 343.9 352.8 361.5 361.7 361.8 328.8 362.2 359.3
37.9 25.5 45.6 42.1 39.6 36.0 35.8 44.1 48.1
1.34 1.45 – 1.24 1.33 1.22 – 1.42 –
0.01 0.09 – 0.07 0.04 0.06 – 0.08 –
aLeast squares means (SAS, 1990). bStatus removed from analysis.
portion of the pellets, missing the entire implant, placed in the cartilage of the ear, placed in the inner 1/3 of the ear, or implant site fluid-filled. Implants were scored as is typical for manufacturer’s quality control tests. Palpations were conducted on the initial implant at approximately d 60 (reimplant), and on the terminal implant approximately 3 wk after its administration, at harvest, and in the laboratory following harvest. At reimplant, BW was obtained on a hydraulic scale suspended using a
two-point load cell system. Both scales were calibrated to be accurate within 0.9 kg. Buller steers were housed in a buller pen following diagnosis. Animals diagnosed with respiratory disease were treated as was typical for the feedlot. Cattle sold early, cattle that died, and bullers were not available for implant site evaluation, and thus were not included in the data. Slaughter Plant Data. All cattle were fed to an endpoint as deter-
TABLE 4. Average daily gain by implant status of the initial implant for 0 to 60 d. Initial wta Status
Normal Abscessed Bunched Separated Partial Missing Cartilage Inner one-third Fluid-filled aLeast
Reimplant wta
ADGa
n
Mean
SEM
Mean
SEM
Mean
SEM
619 44 21 62 75 79 49 79 65
320.9 314.0 315.1 321.8 321.1 315.0 312.9 323.2 324.5
34.5 33.1 37.0 30.8 31.7 30.6 29.5 35.0 33.0
(kg) 454.3 449.4 440.4 453.5 450.8 450.7 446.0 453.8 455.3
42.9 41.8 37.0 38.0 39.2 38.3 32.7 41.4 42.6
2.14 2.22 2.05 2.20 2.13 2.18 2.15 2.09 2.11
0.02 0.05 0.08 0.05 0.04 0.04 0.05 0.04 0.05
squares means (SAS, 1990).
mined by feedlot personnel, and harvested by pen. The pens of cattle were harvested after 124, 143, 145, 161, and 166 d on feed as they became ready. The same person who palpated implants in the live animals palpated ears in the packing plant using the scoring system described previously. Slaughter plant palpations were conducted 64, 85, 80, 97, and 105 d post-reimplanting, respectively. Ears were palpated at chain speed, and only the terminal implant was checked. Trained individuals observed livers, lungs, and carcass trim. Carcass trim was recorded on the chain after the carcass had passed the hot scale. An estimate of trim was made, and any trim >4.5 kg was estimated to the nearest 4.5 kg. The hot weight of each carcass was recorded, adjusted for trim, and divided by the pen dressing percent to calculate final live weight. The above slaughter plant data were collected on all five pens. Laboratory Data Collection. Plant personnel removed ears from steers at the packing plant for four of the five pens, placing each set of ears in individual bags to retain identity. The ears were then transported to the laboratory. The terminal implant for each animal was repalpated in the laboratory to evaluate the agreement between the laboratory palpation and chain-speed palpation. When necessary, the ear was dissected to confirm classification, and the palpater was blind to previous ear scores. Statistical Analyses. A clinically significant threshold of a 5% decrease in ADG as a result of implant abnormalities was assumed. Using a standard deviation of 0.11 kg, it was determined that to detect significant differences in ADG, the sample needed to include 34 abnormalities. Contact with implant manufacturer representatives who conduct quality control palpations in feedlots revealed that the smallest abnormality incidence rate expected would be from 3 to 5%. Hence, it was estimated that 1000 to 1200 animals were needed to detect a
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Implanting Abnormalities in Feedlot Steers
clinically significant effect on ADG (6). A kappa statistic (6) was used to determine the degree of agreement between palpations conducted approximately 3 wk after the terminal implant was administered, and those conducted at the time of harvest. Kappa also was used to determine the agreement of implant palpations conducted in the laboratory with implant palpations conducted at chain speed. The kappa statistic is a measure of agreement between two diagnostic tests adjusted for agreement resulting from chance. Scores can vary between 0 and 1, with values of 1 indicating perfect agreement, values greater than 0.75 representing excellent agreement beyond chance, values between 0.40 and 0.75 representing fair-to-good agreement beyond chance, values below 0.40 indicating poor agreement beyond chance, and values of zero indicating no agreement (6). To analyze the relationships between performance and implant defects, the SAS General Linear Models procedure (7) was used to develop a model and evaluate the implant status on ADG. Models were initially created controlling for pen, initial BW, reimplant BW, carcass trim, and the hospital treatments the animal received. Reimplant BW and trim evaluations were dropped from the initial feeding period model (d 0 to 59), and initial BW was dropped from the 3-wk, chain-speed, and laboratory models (d 60 to slaughter).
Results and Discussion Performance by Cattle with Abnormal Implants. In the overall model, there was a trend for ADG from d 60 to harvest to be affected (P<0.10) by implant defects. These data agree with Nebraska researchers (1), who found that an overall abnormal implant status resulted in 0.06 kg (P<0.01) loss in ADG. The overall model included six (normal, abscessed, bunched, separated, partial, missing, and inner 1/3) of the eight initial categories for both types
TABLE 5. Agreement of implanting abnormality palpations between the classification of implant defects of the terminal implant in the laboratorya and in the slaughter plantb (n = 785). Slaughter plant palpations Laboratory palpations Normal Abscessed Bunched Separated Partial Missing Inner one-third
Inner Normal Abscessed Bunched Separated Partial Missing one-third 509c 3 10 7 17 3 10
10 16d 4 0 0 0 0
11 1 4e 0 1 0 0
25 1 1 3f 3 1 0
22 1 2 2 15g 1 1
28 0 0 2 14 25h 3
22 0 0 0 0 2 5i
aPalpation
performed in laboratory setting with no time constraint. performed in slaughter facility at chain speed (6 to 8 s per animal). cFair to good agreement beyond chance (K = 0.43). dFair to good agreement beyond chance (K = 0.60). ePoor to fair agreement beyond chance (K = 0.19). fPoor to fair agreement beyond chance (K = 0.10). gPoor to fair agreement beyond chance (K = 0.28). hFair to good agreement beyond chance (K = 0.45). iPoor to fair agreement beyond chance (K = 0.18). bPalpation
TABLE 6. Agreement of implanting abnormality palpations between the classification of implant defects of the terminal implant in the feedlota and in the laboratoryb (n = 772). Laboratory palpations Feedlot palpations
Normal Abscessed Bunched Separated Partial Missing Inner one-third aPalpation
Inner Normal Abscessed Bunched Separated Partial Missing one-third
573c 2 1 17 23 4 9
10 5d 2 0 2 2 0
10 0 1e 1 5 2 0
8 0 0 0f 2 2 0
20 0 0 1 18g 10 0
7 1 0 1 0 13h 2
performed in the squeeze chute 3 wk after reimplant with no time constraint. bPalpation performed in laboratory setting with no time constraint. cFair to good agreement beyond chance (K = 0.46). dPoor to fair agreement beyond chance (K = 0.32). ePoor to fair agreement beyond chance (K = 0.08). fNo agreement beyond chance (K = –0.02). gPoor to fair agreement beyond chance (K = 0.32). hFair to good agreement beyond chance (K = 0.44). iPoor to fair agreement beyond chance (K = 0.17).
12 1 0 1 1 0 3i
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Berry et al.
TABLE 7. Agreement of implanting abnormality palpations between the classification of implant defects of the terminal implant in the feedlota and in the slaughter plantb (n = 1004). Slaughter plant palpations Laboratory palpations
Inner Normal Abscessed Bunched Separated Partial Missing one-third
Normal 673c Abscessed 3 Bunched 0 Separated 17 Partial 19 Missing 5 Inner one-third 7
18 11d 1 0 3 4 2
16 0 1e 1 3 0 1
27 0 0 5f 10 2 0
36 0 2 1 22g 5 1
31 2 0 0 10 26h 3
29 0 0 1 0 1 5i
aPalpation
performed in the squeeze chute 3 wk after reimplant with no time constraint. performed in slaughter facility at chain speed (6 to 8 s per animal). cFair to good agreement beyond chance (K = 0.42). dPoor to fair agreement beyond chance (K = 0.39). ePoor to fair agreement beyond chance (K = 0.07). fPoor to fair agreement beyond chance (K = 0.12). gPoor to fair agreement beyond chance (K = 0.28). hFair to good agreement beyond chance (K = 0.42). iPoor to fair agreement beyond chance (K = 0.16). bPalpation
of harvest palpations (chain-speed and laboratory). In a pair-wise least square means comparison of implant defects (Tables 1 and 2), only missing implants compared with normal implants or abscessed implant sites showed less (P<0.05) gain in both harvest palpation models. Cattle with missing implants also showed decreased (P<0.05) ADG in the laboratory palpation model, compared with cattle with bunched pellets and only partial retention of pellets (Table 2). Implant palpations conducted on the terminal implant shortly after implanting (Table 3) were not significant (P>0.10) in the overall ADG d 60 to harvest model. Palpations performed on the initial implant (Table 4) showed no effect (P>0.40) on ADG from d 0 to reimplant. However, failure to demonstrate a difference may have resulted from high variation in ADG during that period. Additional experimental error could have been introduced by cattle entering the study with an undetermined implant status. These data were unobtainable because of re-
straints placed on this study because of its commercial setting. These data suggest that quality control programs have the potential to contribute to a successful implant program. Implant sites that failed to retain the product, measured at harvest either in the laboratory or at chain-speed, resulted in a significant loss of ADG. Our findings suggest that, rather than focusing on the entire array of abnormalities that occur in implants, attention should be devoted to increasing the rate of retention in implant sites. Cattle with abscessed implant sites did not perform worse than cattle with normal implant sites; however, abscesses should be minimized to avoid expulsion of the product. Surface area-altering abnormalities (e.g. bunched pellets, separated pellets) showed no effect on ADG, suggesting that rate of release of the active ingredient into the animal’s blood stream might not be affected by surface area-altering abnormalities, or that rate of release might not alter ultimate performance.
Diagnostic Test of Palpations. Overall kappa scores comparing palpations conducted shortly after implanting and palpation scores conducted at harvest (chain-speed) showed poor agreement beyond chance (kappa = 0.34). However, agreement beyond chance for implant sites determined to be normal in individual comparisons (Table 5) showed fair-to-good agreement (kappa = 0.42), and sites that failed to retain the product showed fair-togood agreement (kappa = 0.42). Overall kappa scores comparing palpations conducted approximately 3 wk post-implanting and laboratory palpations were also low (kappa = 0.35). In individual comparisons (Table 6), scores for missing implants had fair-to-good agreement beyond chance (kappa = 0.44), as did scores for normal implant sites (kappa = 0.46). Overall agreement beyond chance of the two harvest palpations, chainspeed and laboratory, was low (kappa = 0.37). Abscessed implant sites (kappa = 0.60), normal implant sites (kappa = 0.43), and sites that failed to retain the implant (kappa = 0.45) showed fair-to-good agreement beyond chance in individual comparisons (Table 7). All other defect categories had low agreement beyond chance. Outcomes of diagnostic tests comparing harvest palpations to palpations conducted shortly after implanting indicate that 3-wk checks might not be indicative of the final status of the implant, because of changes in the implant site caused either by absorption of the product or by progression of the infection process. One problem associated with performing all palpations at harvest is the long period of time implanters must wait before receiving feedback on their implant program. Harvest palpations would, however, cause less stress on animals, presumably facilitating increased performance. Variability from one implant check to another also must be accounted for when considering the usefulness of quality control pro-
Implanting Abnormalities in Feedlot Steers
grams. Kappa scores for palpations conducted on the same implant sites (laboratory and chain-speed) postmortem showed low agreement beyond chance for most defects. Nonetheless, for missing implants, the one defect that significantly affected ADG in our study, agreement beyond chance was fair-to-good. This result suggests that the objective of finding agreement between implant checks for all implanting abnormalities in this study was too broad, and further research should be conducted that focuses on single defects or smaller groups of defects. Another possible limitation of the study as it was conducted was the low frequency of certain defects (fluidfilled and implants placed in the cartilage), resulting in very little chance of finding significance for these defects.
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Implications Cattle with implant sites that failed to retain the implant showed decreased ADG during the reimplant period. The ADG of cattle with other implanting abnormalities (e.g., abscesses, bunched pellets, separated pellets, partial retention, and poor placement) generally did not differ from ADG of cattle with normal implants. These findings suggest that further research should be conducted to explore methods of improving implant retention. Abnormalities found in the initial implanting had no effect on ADG from d 0 to 59, which may be attributable to high variation in ADG during that period. There also might be less effect resulting from the implant’s ability to extend cattle’s growth curve in the final period than in the differences in the growth curve before d 60. Further research should be conducted to compare the effects of abnormal implantings on ADG of cattle implanted early vs late in the feeding period.
Literature Cited 1. Bryant, L. K., L. J. Perino, D. D. Griffin, A. R. Doster, and T. E. Wittum. 1999. A method for recording pulmonary lesions of beef calves at slaughter, and the association of lesions with average daily gain. The Bovine Practitioner. 33 (2):163. 2. Duckett, S. K., F. N. Owens, and J. G. Andrae. 1997. Effects of implants on performance and carcass traits of feedlot steers and heifers. Symp.: Impact of Implants on Performance and Carcass Value of Beef Cattle. p 63. Okla. Agric. Exp. Stn., P-957. 3. Griffin, D., and L. Perino. 1992. Disease monitoring in packing houses. Proc. of the Seventeenth World Buiatrics Congress and Twenty-Fifth American Bovine Practitioners Conference, vol. 2. p 343. August 31 to September 4, 1992. St. Paul MN. 4. Hollis, L. C. 1989. Proper management of implant technique in feedlot cattle. Compend. Contin. Educ. Prac. Vet. 11:763. 5. Lehman, F. L. 1995. Technical Bulletin 14A. Hoechst-Roussel Agri-Vet Co., Somerville, NJ. 6. Martin, S. W., A. H. Meek, and P. Willeberg. 1987. Veterinary Epidemiology. Iowa State University Press, Ames, IA. 7. SAS. 1990. SAS/STAT® User’s Guide: Statistics (Release 6.04 Ed.). SAS Inst. Inc., Cary, NC.