| ||Take home message | Suckling calves | Yearlings on pasture | Feedlot cattle | Reimplanting | Implants combined with feed additives | Summary | References
This is a fact sheet from the Nutrition and Management section of the Alberta Feedlot Management Guide,Second Edition published September 2000. The 1200 page guide is available for purchase on CD-ROM.
Take Home Message
- Growth implants registered for beef cattle in Canada can increase growth rate by from five to twenty percent and improve feed conversion efficiency by five to ten percent.
- The improved performance can provide an extra return of $7.00 to $10.00 for each dollar spent for the growth implant.
- When these registered implants are properly used they reduce the cost of production and result in leaner carcasses at any given age or weight.
Thirty-nine field trials, involving 1840 suckling calves in thirty-eight herds were conducted across Alberta. The results showed that, averaged over all trials, implanted heifer and steer calves gained just over 5% more to weaning than those without implants (Table 1). This resulted in an extra 15 to 17 pounds (7 to 8 kg) weaned weight in implanted calves. Other researchers have reported increased weaned weights of 7.5 to 35 pounds (3.5 to 16 kg). Depending on current prices, the implanted calves are worth at least an additional $12.00 to $30.00 at weaning. The Alberta results represent an additional return of at least $6.00 or more for every $1.00 spent on the implant.
Table 1. Response of Suckling Calves to Growth Implants; Alberta Field Trials - 1980 and 1981.
1Pounds of additional weaned weight in implanted suckling calves over unimplanted calves.
Improvement of Implanted Claves Over Control
|Year ||Number of Trials ||Improved |
|Pounds of |
|Pounds of Extra Gain1 |
1980 & 81
Yearlings On Pasture
Nine field trials involving 640 yearling steers on pasture were conducted across Alberta (Table 2). The results of these trials showed that the growth implants Ralgro® and Synovex-S® increased the gains on pasture in a range of 13 to 22 percent. The average increased gain was 36 pounds (16.5 kg). In another individual trial, on a grazing reserve in Alberta, implanted steers gained an average of 30 pounds (13.6 kg) more than steers which did not receive an implant. Other researchers have reported improvements in gains of from 7 to 22 percent and improvements in feed efficiency of from 3 to 11 percent (Table 3). These represent additional weight gains of 17 to 79 pounds (8 to 36 kg), depending on the length of the trials. A part of the variation may be due to nutritional factors. Deficiencies in energy or minerals can limit growth and lower the response to growth implants. Implants produce the most benefit when other factors affecting growth are not limiting. Depending on prices for short keep feeders these results suggest that implanted steers on pasture could produce extra gains worth from $12.00 to more than $50.00. The implanted steers may consume more pasture to produce the increased gains but, as noted above, implanted animals consume less feed per pound of gain (Table 3). Livestock economists have estimated that the additional net return to implanted steers on pasture would be between $26.00 and $50.00 per animal for the extra 26 pounds (11.8 kg) of pasture gain (updated for 2000 prices). If the cost of the implant is $1.50, the return per dollar of implant cost is at least $17.00.
Table 2. Response of Yearling Steers on Pasture to Growth Implants; Alberta Field Trials - 1980 and 1981.
|Trial # |
|Total head --------- -------------354 |
|Average performance (1980) |
|Total head ----- ------- ---------286|
|Average performance (1981) |
|Both years, total trials = 13 |
|Total head ---- ------- ----------640|
|Average performance, both years |
|1All trials with both implants used |
|1Total head in paired trials 572 |
|1Average performance in paired trials |
Table 3. Summary of Research Comparing the Response of Steers to Traditional Growth Implants; Reported by the American Society of Animal Science.
1Note 1: ‘repeat’ designates trials where implants were repeated. Total pounds of gain are higher because of the longer feeding period. Note also that the increase from the second implant in the California trial is less than the increased gain from the first implant.
Response of implanted steers - improvement over controls
|Test Location |
|(3 repeats 273 days)1 || |
|(1 repeat 191 days)1 |
|(no repeats with Compudose) |
Note 2: Research published from 1984 to 1996 shows that the ‘new generation’ of implants, using trenbolone acetate combined with estrogen, have produced daily gain improvements of 4 - 11% over those of the ‘traditional implants’ used before 1994. The new generation implants also improved feed efficiency by 4 - 8% over traditional implants.
There are a great many research results from implanting feedlot cattle with all of the various growth promotants (Table 3). While the results vary with the conditions and the type of implant, the average improvement in gains are similar among the traditional types of implants available in Canada. Generally the response of feedlot cattle is similar to those reported for yearlings on pasture. One summary of 35 trials reported responses ranging from 1 to 35 percent and averaging 14.5 percent improvement in daily gain. In another summary of 10 trials feed efficiency (the amount of feed per unit of gain) was improved by 3.8 to 11 percent in the implanted steers, with an average improvement of feed conversion of 6.7 percent. The total cost of finishing the implanted steer is estimated at $31.61 less than costs for one which was not implanted (Table 4). This cost saving assumes an average improvement in daily gain of 15% and improved feed conversion of 9% on steers fed from 720 pounds to finish at 1,200 pounds (at 2000 costs for interest, feed and yardage). The reduced cost is $9.88 for every $1.00 spent for the product and labour costs of implanting.
Most of the Canadian registered growth implants may now be used more than once in feeder cattle. Because the effective period for the Compudose® implant is up to 200 days, a reimplant is not necessary (Table 3). For the other implants the effective period for the product has been reported at from 80 to 120 days. Research at the University of Nebraska, Kansas State University and Beltsville Maryland has shown that implanting steers at the beginning of the growing phase, and again at the beginning of the finishing phase of the feeding period, produced additional gains over steers implanted only once. In most cases, however, the response to the second implant was less than the response to the first. Implanting calves in the suckling phase did increase weaning weights. However, the lifetime gain for steers implanted three times (in the suckling, growing and finishing phases) was 6 to 7 percent less than the gains for steers only implanted in the last two phases of growth. These studies suggest that a producer who is retaining ownership of cattle through to finish would receive more benefit from implants if they were used only in the growing and finishing phase of feeding. A feeder purchasing these implanted calves would still benefit from using another implant in the feedlot but the response would be less than if the calves had not been implanted in the suckling phase.
The newly registered products Revalor® (March 1994) and Synovex Plus® (April 1996) contain synthetic androgen (male sex hormone) combined with oestradiol, so they work differently than most of the other implants. They are most effective when the steers are on full feed. For that reason it is recommended as a ‘terminal’ implant to be used in the last 120 days of a feedlot finishing period. Research in the U.S. and Canada in the last twelve years has shown that these ‘new generation’ growth implants will improve gains by 5 - 11% over the traditional implants. The ‘new generation’ of growth implants will also give 5 - 8% more gain per pound of feed (improved feed efficiency) compared with the traditional growth implants. At the same time the cost of the implant is currently more than three times higher than the traditional implants, so the return per dollar spent is about the same for both types of products (see Table 4).
Implants Combined With Feed Additives
Growth implants combined with feed additives Rumensin® and Bovatec® are effective in feedlot programs. Research has shown that the growth implants produce the usual improvement in daily gains and feed efficiency; while the ionophore feed additives, in combination with the growth implants, will reduce the amount of feed required for a given amount of gain by an additional 7 to 8 percent.
Growth implants which are now registered for beef cattle in Canada can increase growth rate by from five to twenty percent, and improve feed conversion efficiency by five to ten percent. The improved performance can provide an extra return of $7.00 to $10.00 for each dollar spent for the growth implant. When these registered implants are properly used they reduce the cost of production and result in leaner carcasses at any given age or weight.
Table 4. Partial Budget - Economics of Growth Implants (Feedlot Steer - Days on Feed).
- Agriculture and Agri-Food Canada, 1989 to 1994. Annual reports on chemical and biological testing for the fiscal years 1989 through 1994; Agri-Food Safety Division, Food Production and Inspection Branch, Agriculture and Agri-Food Canada, Ottawa.
- Anderson, Peter T. 1995. Effects of steroid implants on feed intake. Proceedings of the symposium: Intake by Feedlot Cattle - Oklahoma State University - P942, July 1995. pp 97-104.
- Basarab. J. A. et al. 1984. Growth response of beef cattle at pasture to zeranol or progesterone-oestradiol implants. Can. J. Anim. Sci. 64: 119- 126.
- A. DiConstanzo, 1996. Effects of protein supplementation and implanting strategy on performance of feedlot steers. Proc. Midwest Sec., Am. Soc. Anim. Sci. 74: 76 (Abstr.).
- Kenneth Eng, 1996. Recent implant approvals add to arsenal of production enhancers. Feedstuffs, March 18, 1996, pp 12, 23.
- R. L. Preston, et al. 1996. Effects of implants with varying ratios of trenbolone acetate and oestradiol on performance, plasma urea nitrogen and carcass characteristics in English, Brahman and Continental crossbred steers. Proc. Midwest Sec. Am. Soc. Anim. Sci. 74: 87, (Abstr.).
- Bruce D. Schanbacher, 1984. Manipulation of endogenous and exogenous hormones for red meat production. J. Anim. Sci. 59:1621-1630.
- World Health Organization, 1988. Evaluation of certain veterinary drug residues in food. Thirty-second Report on the Joint FAO/WHO Expert Committee on Food Additives, Technical Report Series 763. World Health Organization, Geneva.
1Note that the returns per $1.00 spent to implant assume an equivalent grade and carcass
|Descriptions and Assumptions:|
|Type of Animal on feed: ||Feeder Steer ||Purchase weight: ||720 lbs |
|Target Sale Weight: ||1200 lbs1 ||Total Gain: ||480 lbs |
|Yardage costs: ||$0.20 per day ||Interest Charges: ||8.00%|
|Barley costs: ||$180/tonne ||$3.92/bu ||$0.082/lb |
|Typical feed efficiency without implants:|
| - 7 pounds of feed per pound of gain or 142.9pounds of gain per 1,000 pounds of feed |
|Typical improvement in performance from Implants: |
TBA + Estrogen
| - Improved daily gain |
| - Improved feed/gain ratio |
|Cost and Return Comparisons:|
| - 1. Cost of Steer: 720 lb at $75.00 per 100 lb |
54 - 0
| - 2. Cost of Feed: 480 lb of gain requires |
| - Total Cost of Feed @: $180.00 per tonne |
| - Daily gain in pounds per day |
| - Days to finish (pounds of gain/daily gain): |
| - 3. Cost of Yardage @ $0.20 per day: |
| - 4. Cost of Bedding @ $0.0 7 per day: |
| - 5. Interest on Feed @ 8.0%: |
| - (feed cost/2 x int%/100/365 x days fed)5.34 |
| - 6. Interest on Purchase Cost of Feeder Steer @ 8.0%: |
| - (purchase price x int%/100/365 x days fed): |
| - 7. Cost of implants (including labour) : |
| - Cost of implants per dose: |
| - Hourly wage for implant operator: $15.00 |
|- Number of steers processed per hour:50 |
| - Labour cost per implant per head: |
| - Total cost per implant: |
| -- Number of days implant is effective before reimplanting: |
| - Number of days in feeding period for implanted cattle to reach |
- target sale weight:
| - Number of implants required in feeding period: |
| - Total cost of implanting, including product and labour: |
|Total Cost for non-implant and implant: |
|Cost savings due to implants: |
|1Returns per $1.00 spent to implant |
yield in implanted and non-implanted animals.
Ross Gould, P.Ag.(ret), 2000. Alberta Feedlot Management Guide.
- Research suggests that, at any given weight, carcasses implanted animals will contain less fat. As a result the grade and marbling scores may differ between implanted and non-implanted animals.
- No provision was made in this spreadsheet for differences in carcass yield (which are usually small)or premiums/discounts for marbling score and backfat levels.
- The reader should adjust the returns accordingly.
- This partial budget orginally a Quattro Pro worksheet - File: IMPLECON.WB2. For a copy contact Ross Gould, P.Ag., Ph, 403-460-88704; E-mail, firstname.lastname@example.org.