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Effects of Liquid Supplement Feeder Wheel Width and Turning Capability on Supplement Intake by Beef Heifers1
The Professional Scientist (2003):321–325 CASE Animal STUDY: Liquid Feed19 Intake
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CSupplement S : Effects of Liquid Feeder Wheel Width ASE TUDY
and Turning Capability on Supplement Intake by Beef Heifers1 P. A. Davis*, PAS, W. E. Kunkle*2 , PAS, L. R. McDowell*, and J. D. Arthington, PAS†3 University of Florida-IFAS, *Department of Animal Sciences, Gainesville, FL 32611, and †Range Cattle Research and Education Center, Ona, FL 33865
Abstract Effects of reducing liquid supplement feeder wheel width and turning capability on ad libitum liquid supplement intake were evaluated. The experiment was conducted in the summer 2000 at two Florida locations: Gainesville and Ona. Four treatments consisted of 1) standard lick wheel (5.1 cm wide) with no turning restriction (S-NR), 2) standard wheel with turning restricted to 330o (S-R), 3) narrowed lick wheel (1.9 cm wide) with no turning restriction (NW-NR), and 4) narrowed lick wheel with turning restricted to 330o (NW-R). Intakes of a 16% CP liquid supplement from these feeders were compared using a 4 x 4 Latin square design with five crossbred beef heifers (350 to 386 kg initial BW) in each of four bahiagrass pastures (Paspalum notatum; 1.6 ha in Gainesville and 1.2 ha in Ona), over four 21-d periods. Heifers assigned to treatments S-NR and N-R during periods
1This research was supported by the Florida Agric. Exp. Stn. and is approved for publication as R-09179. 2Deceased. 3To
whom correspondence should be addressed: [email protected]
3 and 4 received a sustained release Cr oxide bolus and Yb chloride blended in their liquid supplement (340 ppm Yb). Intake of each animal was determined by measuring Cr and Yb concentrations in feces from three dates in each period and then averaged across days to estimate fecal output and supplement intake for each animal. At Gainesville, average supplement intake for treatments S-NR, S-R, NW-NR, and N-R were 2.67, 2.00, 2.21, and 1.60 kg/d, respectively. The supplement intake for S-R was 25% less (P<0.01) than S-NR; intake for N-NR was 17% less (P<0.02) than S-NR. The supplement intake for NW-R was 40% less (P<0.01) than SNR. At Ona, supplement consumption for treatments S-NR, S-R, NW-NR, and NW-R were 3.08, 3.03, 3.40, and 2.38 kg/d, respectively. The supplement intake for NW-R was 23% less (P<0.01) than S-NR. There were no differences in supplement intake between S-NR, S-R, and N-NR treatments at Ona. The estimated supplement intake for each animal was determined and CV calculated for each pasture. At Gainesville, the CV for S-NR and NW-R was 26 and 15%, respectively. At Ona, the CV for SNR and N-R was 23 and 35%, respectively. Reducing lick wheel width to 1.9 cm and restricting its rotation reduced liquid supplement consumption 40% and 23% at Gainesvile and Ona, respectively.
(Key Words: Molasses, Lick Wheel, Intake, Cattle.)
Introduction Liquid supplements, offered freechoice, are common forms of energy and protein supplementation for beef cattle (Pate and Kunkle, 1989). Their popularity is related to a reduction in labor and operating costs required for their implementation in beef cattle production systems (Whitlow et al., 1976). Most liquid supplements use molasses as a base, and may contain CP as non-protein nitrogen, natural protein, vitamins, minerals and(or) growth promotants. Liquid supplements can be fed in amounts that allow for ad libitum consumption and may prove more profitable than dry supplements under pasture conditions (Grelan and Pearson, 1977). Lick wheel feeders are a common method of delivering molasses-based liquid supplements to beef cattle on pasture. The use of lick wheel feeders allow for less feeder space required per animal than in interval feeding in open troughs (Whitlow et al., 1976). In many situations, however, over-consumption of liquid feed is a problem for beef cattle producers. Some technologies now exist and have been employed to limit and(or) regulate
322
consumption of liquid supplements (Bowman et al., 1999). This experiment was designed to investigate the effects of reducing feeder lick wheel surface area, restricting lick wheel turning capability, and doing both in combination on liquid supplement intake and variation in intake of yearling beef heifers.
Davis et al.
University of Florida Animal Care and Use Committee (#A551). Animals. Forty yearling heifers (Brangus-crossbred at Gainesville and Braford at Ona; 273 to 386 kg BW) were assigned at random to four bahiagrass (Paspalum notatum) pastures at two Florida locations (five heifers/pasture; 1.62 ha at Gainesville; 1.21 ha at Ona). All heifers received routine health management, which included dewThis experiment was conducted at orming and vaccination for the University of Florida, Santa Fe clostridial and respiratory diseases, Beef Unit, located in Alachua County, pasturella, leptospirosis, and vibriofor 84 d (July 6 to September 28 and sis. at the University of Florida Range Diets and Feeding Procedures. Cattle Research and Education Treatments and pastures were arCenter, Ona, for 84 d (July 13 to ranged in 4 x 4 Latin square design October 10). All procedures for this balanced for carryover effects experiment were approved by the (Cochran and Cox, 1956). Each of the four periods was 21 d in length. Molasses-based liquid supplement (Suga-Lik #500; United States Sugar Corporation, Clewiston, FL [Table 1]) TABLE 1. Composition of basal was offered in amounts sufficient to molasses supplement1, 2. ensure ad libitum consumption using Item Amount, % (± SD) 288-kg capacity commercial liquid supplement feeders with one lick wheel per feeder (RMI, Inc., Bartow, FL). The wheel was either standard DM 72.78 ± 0.34 width (5.1 cm) or narrowed to 1.9 CP 17.03 ± 1.39 cm. Moreover, each wheel width Total sugars as inverts 41.09 ± 1.14 also was evaluated with nonrePhosphorus 0.62 ± 0.02 Potassium 4.01 ± 0.15 stricted, normal, continuous turning Calcium 0.79 ± 0.04 capability) compared with an added Sulfur 0.73 ± 0.05 device, which restricted the wheel Sodium 0.12 ± 0.03 from making a full rotation. The standard width, non-restricted wheel 1Liquid feed (Suga-Lik #500, United (S-NR) feeder served as the control. States Sugar Corporation, Clewiston, Restricted wheels were developed by FL) samples collected weekly during inserting a 15.2-cm carriage bolt both experiments and at each through a wheel spoke near the location. Values represent means of licking surface in order to restrict composited weekly samples. turning to approximately 330° in one 2Free-choice mineral mix in addition direction. Therefore, the three to liquid supplement contained 17% treatments were standard width, Ca and 9% P as calcium carbonate, turning restricted (S-R); narrow monocalcium phosphate and width, non-restricted turning (N-NR); dicalcium phosphate, 25% salt as sodium chloride, 0.25% Mg as and narrow width, restricted turning magnesium oxide, 0.15% Cu as (N-R). copper sulfate, 0.01% Co as cobalt Liquid supplements were added to sulfate, 0.01% I as calcium iodate, feeders on Monday of each week and 0.20% Mn as manganous sulfate, replenished on other days as neces0.0040% Se as sodium selenite, and sary. Liquid supplement consump0.40% Zn as zinc sulfate. tion was recorded at each offering by weighing the feeders before and after
Materials and Methods
addition of supplement using a spring dial scale. Supplement consumption was calculated for each week during the 3-wk periods. Administration of Dual Marker System. During periods 3 and 4, heifers on S-NR and N-R treatments were administered a Captec Crsesquioxide bolus (Nufarm Limited, Auckland, New Zealand). The ability to include all treatments was limited due to the cost of reagents; therefore, the treatment with the greatest amount of restriction (NW-R) was compared with the standard device (S-NR). This was done in order to estimate total fecal output for the estimation of individual liquid supplement intake. Additionally, Ybchloride solution (Rhodia Inc., Phoenix, AZ) was added to the liquid supplements at a calculated concentration of 340 ppm Yb. This concentration was chosen to allow for analysis and detection of liquid supplement intake to 0.11 kg/d, based on expected detection limits of Yb and estimated quantities of feces. The Yb-chloride solution was diluted with distilled, deionized water, so that a field level of 2 mL was added to 0.454 kg of liquid supplement to attain the 340 ppm Yb in the liquid supplements. The solution was then mixed thoroughly into the liquid supplement using a cordless electric drill with a paint stirring attachment. Sampling and Data Collection. Liquid supplement that was left in the feeder and liquid supplement after addition and blending were sampled weekly. Fecal grab samples were taken from the rectum on four occasions between d 10 and 21 of periods 3 and 4 for all heifers on SNR and N-R treatments. Laboratory Analyses. Liquid supplement was composited by period and analyzed for DM, CP, total sugars as inverts, Ca, P, K, S, and Na. Dry matter was determined by vacuum over sand drying, CP by Kjeldahl N determination (AOAC, 1990), total sugars as inverts by gravimetric Munson-Walker method (Browne and Zerban, 1941), and minerals by inductively coupled
CASE STUDY: Liquid Feed Intake
323
University of Florida-IFAS Analytical Research Laboratory for Yb concentration using ICP (Spectro Ciros Model FTCEA000, Spectro Co., Lick wheel treatment Fitchburg, MA) according to Fassel (1978). Item S-NR1 S-R2 NW-NR3 NW-R4 Period Avg Liquid supplement samples from SNR and N-R treatments, taken during the week that fecal sampling ocPeriod Intake, kg/head daily curred, were prepared and analyzed 1 2.25 1.15 2.03 0.50 1.48 for Yb using the previously described 2 1.84 1.99 2.32 1.43 1.90 methods. The actual Yb concentra3 3.02 2.69 2.02 1.63 2.34 tions in liquid supplements were 4 3.57 2.20 2.46 2.82 2.76 used in the equation to estimate Avg 2.67a 2.00b 2.21b 1.60c 2.12 liquid supplement consumption by individual animals. For fecal Cr 15.1-cm wide lick wheel, unrestricted rotation. analysis, a 1-g subsample of ground 25.1-cm wide lick wheel, wheel rotation restricted to ~330°. feces was ashed for 1.5 h at 600°C, 31.9-cm wide lick wheel, unrestricted rotation. and the ash was prepared according 41.9-cm wide lick wheel, wheel rotation restricted to ~330°. to the procedure described by Willa,b,cAverage intakes lacking a common superscript differ (P<0.05); SE = 0.27. iams et al. (1962). Fecal Cr concentration was determined using the Perkin-Elmer model 5000 atomic plasma emission spectroscopy (ICP). beaker at 500°C for 8 h. Ash was absorption spectrophotometer These analyses were conducted at the recovered in 20 mL of a 0.1-M (Perkin-Elmer, Norwalk, CT). Fecal laboratory of United States Sugar solution of output estimates were calculated Corporation Laboratory (Clewiston, diethylenetriaminepentaacetic acid using fecal Cr concentration and the FL). in 0.3 N NaOH with 0.1% K. The daily Cr release from the bolus. Fecal samples were dried in a solution was extracted for 12 h on a The daily release rate of Cr from forced-air oven at 100°C for 24 h and shaking device and then filtered. The the Captec was validated using six crossbred beef steers (227 kg BW, 1.5 ground in a Wiley mill to pass a 1procedure is described by Ellis et al. yr) in metabolism stalls at the Ona mm screen. After grinding, a 1-g (1982). The final extraction was subsample was ashed in a 50-mL submitted in scintillation vials to the location. Steers were offered bahiagrass hay ad libitum to allow for refusal and to determine accurate DM intake. Bahiagrass hay offered and TABLE 3. Effect of feeder wheel width and rotation restriction on freerefused was recorded daily. Each choice consumption—Ona. steer was dosed with one Captec bolus on d 1, and total feces were Lick wheel treatment collected for 21 d during September 2000. All feces were collected in Item S-NR1 S-R2 NW-NR3 NW-R4 Period Avg galvanized steel pans and weighed daily. Feces were thoroughly mixed, and a subsample was taken and dried Intake, kg/head daily Period in a forced-air oven to determine 1 3.25 2.53 3.31 1.12 2.55 DM. Fecal samples from each animal 2 3.00 3.41 3.31 3.05 3.19 collected on d 8 through 16 were 3 2.95 3.63 3.00 2.75 3.08 4 3.14 2.55 4.02 2.62 3.08 analyzed for Cr concentration using Avg 3.08a 3.03a 3.41a 2.38b 2.98 the methods as previously described. It was determined that each bolus 15.1-cm wide lick wheel, unrestricted rotation. had a Cr release of 0.99 g/d, used to 25.1-cm wide lick wheel, wheel rotation restricted to ~330°. estimate fecal DM output with the following equation from Earley et al. 31.9-cm wide lick wheel, unrestricted rotation. (1999): Fecal DM output (g/d) = (Cr 41.9-cm wide lick wheel, wheel rotation restricted to ~330°. intake, g/d) / (fecal Cr concentration, a,b,cAverage intakes lacking a common superscript differ (P<0.05); SE = 0.27. g/g DM). Individual animal daily liquid supplement consumption was
TABLE 2. Effect of feeder wheel width and rotation restriction on freechoice consumption—Gainesville.
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estimated using daily fecal DM, fecal Yb concentration, and Yb concentration of liquid supplement in the following equation from Earley et al. (1999): Supplement intake (g/d) = (fecal Yb concentration, g/g * fecal output, g/d) / supplement Yb concentration (g/g). Individual heifer intake was averaged by period for each pasture, and a CV was calculated. The CV was determined by dividing the SE by the mean for each pasture. Statistical Analyses. Treatment, pasture, and period data obtained from the 4 x 4 Latin square design were subjected to the GLM procedure of SAS (1985). The interaction of treatment x pasture x period was chosen as the error term. Least squares means were separated when F-test was significant (P< 0.05).
Results and Discussion Liquid supplement intakes for the wheel width and restriction trials at Gainesville and Ona are summarized in Tables 2 and 3. At Gainesville, daily supplement consumption was reduced (P<0.01) by 25%, to 2.00 kg/ d by restriction of the standard wheel width (S-R) compared to the unrestricted standard wheel (S-NR; 2.67 kg/d). Reducing wheel width to 1.9 cm (NW-NR) reduced (P<0.02) consumption by 17%, to 2.21 kg/d. There was no significant difference between S-R and NW-NR. At the Gainesville location, narrow width with restricted turning lowered (P<0.001) consumption by 40% to 1.60 kg/d. At the Ona location, rotation restriction of a standard width lick wheel (S-R) resulted in daily consumption similar to control (P=0.79). Reducing the wheel width to 1.9 cm also did not significantly reduce consumption (P=0.12). The most effective treatment for lessening intake was narrowing and restricting rotation of the lick wheel (NW-R). The NW-R treatment gave a 23% decline (P<0.01) in consumption to 2.38 kg/d. Although not well documented, the physical manipulation of feeding devices is commonplace
Davis et al.
within the livestock-producing community. McLennan et al. (1991) compared consumptions of molassesurea liquid supplement delivered in a lick tank with a lick-wheel device similar to the current study. Supplement intake from this system was compared with an open trough feeder. The use of the lick-wheel feeder provided a significant reduction in supplement consumption. Nolan et al. (1975) experimented with physical means of limiting liquid supplement intake. A waximpregnated wooded raft was floated on liquid supplement in an open trough in attempt to limit consumption. Tritiated water was used to measure intake and a CV of 52% was reported. The scientific literature is limited on this subject, and it becomes difficult to determine whether these results are within normal ranges. Most studies in this area have dealt with comparisons of trough space per animal, supplement amount, supplement form, and group vs. individual feeding. At Gainesville, the CV for supplement intake on the standard, unrestricted wheel was greater (26%; mean intake 2.67 kg/d) than the narrowed, restricted wheel (15%; mean intake 1.60 kg/d). In contrast, the narrowed, restricted wheel at Ona provided more variation in intake (35%; mean intake 2.38 kg/d) compared with the standard, unrestricted wheel (23%; mean intake 3.08 kg/d). The CV for both treatments at Gainesville (26 and 15%) and the narrowed, restricted wheel at Ona (23%) were less than 107% CV for molasses-urea supplements reported by Bowman et al. (1995b) and 37% CV reported by Langlands and Donald (1978). The variation values also were less than those reported by Webb et al. (1973), Nolan et al. (1975), Llewelyn et al. (similar to Ona; 1978), and Mulholland and Coombe (1979), who reported CV of 46, 52, 23, and 64%, respectively. Previous research (Wagnon, 1966) illustrated that social dominance and social interactions play an important role in feeding behaviors and supple-
ment consumption. This is most apparent in herds with mixed ages and sizes of animals. Bowman et al. (1995a) observed that 2-yr-old cows consumed less liquid supplement from lick tanks than 3-yr-old cows on November range in Montana. The animals used in these trials were very similar in age, size, and breed type. Thus, the variation in supplement consumption is more likely due to feeding behavior, individual animal preferences, and nutritional needs. Technologies now exist and have been employed to limit consumption of liquid supplements by grazing ruminants. Lick feeders capable of dispensing predetermined, programmed quantities of supplement from a main tank into auxiliary feeding tubs using a metered gravity flow system are now available (Bowman et al., 1995a). This is being done in an effort to control more closely individual animal consumption, and it complements the objectives of this research. The effectiveness of these delivery systems was reported by Bowman et al. (1999).
Implications Physical manipulation of feeder lick wheels appears to be an effective means of limiting liquid supplement intake for beef heifers on pasture. Results from these experiments indicate that reducing the surface area of the lick wheel in combination with restricted rotation is most effective. This is a relatively simple technology that could be implemented by the supplement feeder industry with little additional cost to the livestock producer.
Acknowledgments Appreciation is extended to the Liquid Feed Committee of the American Feed Industry Association for their partial financial support of this research, the United States Sugar Corporation (Clewiston, FL) for the donation of liquid feed, and RMI, Inc. for their donation of supplement feeders. Appreciation is also ex-
CASE STUDY: Liquid Feed Intake
tended to Carol Piacitelli, Toni Wood, Charles Stevens, Bert Faircloth, Steve Chandler, and Angelita Mariano for their technical assistance during the conduct of these studies. The authors are also grateful to graduate students Bradley Austin and Edgar Rodriguez for their help in sample and data collection.
Browne, C. A., and F. W. Zerban. 1941. Physical and Chemical Methods of Sugar Analysis. John Wiley and Sons, London, UK Cochran, W. G., and G. M. Cox. 1956. Experimental Designs. (2nd Ed.). John Wiley and Sons, New York, NY. Earley, A. V., B. F. Sowell, and J. P. G. Bowman. 1999. Liquid supplementation of grazing cows and calves. Anim. Feed Sci. Technol. 80:281. Ellis, W. C., C. Lascano, R. Teeter, and F. N. Owens. 1982. Solute and particulate flow markers. In Protein Requirements for Cattle: Symposium. F. N. Owens (Ed.). pp 37-56. OK St. Univ., Stillwater MP-109.
Literature Cited AOAC. 1990. Official Methods of Analysis (15th Ed.). Association of Official Analytical Chemists, Washington, DC Bowman, J. P. G., B. F. Sowell, and D. L. Boss. 1995a. Effect of liquid supplement delivery method on forage intake and digestibility by cows on native range. Proc. West. Sect. Am. Soc. Anim. Sci. 46:391. Bowman, J. P. G., B. F. Sowell, D. L. Boss, and H. Sherwood. 1999. Influence of liquid supplement delivery method on forage and supplement intake by grazing beef cows. Anim. Feed Sci. Technol. 78:273. Bowman, J. P. G., B. F. Sowell, and J. A. Paterson. 1995b. Liquid supplementation for ruminants fed low-quality forage diets: A review. Anim. Feed Sci. Technol. 55:105.
Fassel, V. A. 1978. Quantitative elemental analyses by plasma emission spectroscopy. Science 202:183. Grelan, H. E., and H. A. Pearson. 1977. Liquid supplements for cattle on southern forest range. J. Range Mgmt. 30:94. Langlands, J. P., and G. E. Donald. 1978. The nutrition of ruminants grazing native and improved pastures. II. Responses of grazing cattle to molasses and urea supplementation. Aust. J. Agric. Res. 29:875. Llewelyn, D. T., T. J. Kempton, and J. V. Nolan. 1978. Liveweight responses in heifers fed a meatmeal-molasses supplement. Proc. Aust. Soc. Anim. Prod.12:64. McLennan, S. R., D. J. Hirst, R. K. Shepherd, and K. R. McGuigan. 1991. A comparison of various methods of feeding supplements of urea, sulfur and molasses to weaner beef heifers during the dry season in northern Queensland. Aust. J. Exp. Agric. 31:153.
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Mulholland, J. G., and J. B. Coombe. 1979. Supplementation of sheep grazing wheat stubble with urea, molasses and minerals: Quality of diet, intake of supplements and animal response. Aust. J. Exp. Agric. Anim. Husb. 19:23. Nolan, J. V., B. W. Norton, R. M. Murray, F. M. Ball, F. B. Roseby, W. Rohen-Jones, M. K. Hill, and R. A. Leng. 1975. Body weight and wool production in grazing sheep given access to a supplement of urea and molasses: Intake of supplement/response relationships. J. Agric. Sci. 84:39. Pate, F. M., and W. E. Kunkle. 1989. Molassesbased feeds and their use as supplements for brood cows. Circular No. S-365. FL Agric. Exp. Stn., Institute of Food and Agricultural Sciences, Gainesville, FL. SAS. 1985. SAS User’s Guide: Statistics (Version 5 Ed.). SAS Inst., Cary, NC. Wagnon, K. A. 1966. Social dominance in range cows and its effect on supplemental feeding. Calif. Agric. Exp. Sta. Bull. 819:1-32. Webb, D. W., E. E. Bartley, and R. M. Meyer. 1973. Feeding ammonium acetate in molasses liquid supplement to lactating dairy cows. J. Dairy Sci. 56:1102. Whitlow, L. H., S. P. Marshall, H. H. Van Horn, and J. R. Flores. 1976. Liquid feed passage route into stomach compartments, influence of abomasal infusions on plasma glucose, and supplementation of dry rations with liquid feeds from lick-wheel feeders. J. Dairy Sci. 59:675. Williams, C. H., D. J. David, and O. Iismaa. 1962. The determination of chromic oxide in faeces samples by atomic absorption spectrophotometry. J. Agric. Sci. 59: 381.
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CSupplement S : Effects of Liquid Feeder Wheel Width ASE TUDY
and Turning Capability on Supplement Intake by Beef Heifers1 P. A. Davis*, PAS, W. E. Kunkle*2 , PAS, L. R. McDowell*, and J. D. Arthington, PAS†3 University of Florida-IFAS, *Department of Animal Sciences, Gainesville, FL 32611, and †Range Cattle Research and Education Center, Ona, FL 33865
Abstract Effects of reducing liquid supplement feeder wheel width and turning capability on ad libitum liquid supplement intake were evaluated. The experiment was conducted in the summer 2000 at two Florida locations: Gainesville and Ona. Four treatments consisted of 1) standard lick wheel (5.1 cm wide) with no turning restriction (S-NR), 2) standard wheel with turning restricted to 330o (S-R), 3) narrowed lick wheel (1.9 cm wide) with no turning restriction (NW-NR), and 4) narrowed lick wheel with turning restricted to 330o (NW-R). Intakes of a 16% CP liquid supplement from these feeders were compared using a 4 x 4 Latin square design with five crossbred beef heifers (350 to 386 kg initial BW) in each of four bahiagrass pastures (Paspalum notatum; 1.6 ha in Gainesville and 1.2 ha in Ona), over four 21-d periods. Heifers assigned to treatments S-NR and N-R during periods
1This research was supported by the Florida Agric. Exp. Stn. and is approved for publication as R-09179. 2Deceased. 3To
whom correspondence should be addressed: [email protected]
3 and 4 received a sustained release Cr oxide bolus and Yb chloride blended in their liquid supplement (340 ppm Yb). Intake of each animal was determined by measuring Cr and Yb concentrations in feces from three dates in each period and then averaged across days to estimate fecal output and supplement intake for each animal. At Gainesville, average supplement intake for treatments S-NR, S-R, NW-NR, and N-R were 2.67, 2.00, 2.21, and 1.60 kg/d, respectively. The supplement intake for S-R was 25% less (P<0.01) than S-NR; intake for N-NR was 17% less (P<0.02) than S-NR. The supplement intake for NW-R was 40% less (P<0.01) than SNR. At Ona, supplement consumption for treatments S-NR, S-R, NW-NR, and NW-R were 3.08, 3.03, 3.40, and 2.38 kg/d, respectively. The supplement intake for NW-R was 23% less (P<0.01) than S-NR. There were no differences in supplement intake between S-NR, S-R, and N-NR treatments at Ona. The estimated supplement intake for each animal was determined and CV calculated for each pasture. At Gainesville, the CV for S-NR and NW-R was 26 and 15%, respectively. At Ona, the CV for SNR and N-R was 23 and 35%, respectively. Reducing lick wheel width to 1.9 cm and restricting its rotation reduced liquid supplement consumption 40% and 23% at Gainesvile and Ona, respectively.
(Key Words: Molasses, Lick Wheel, Intake, Cattle.)
Introduction Liquid supplements, offered freechoice, are common forms of energy and protein supplementation for beef cattle (Pate and Kunkle, 1989). Their popularity is related to a reduction in labor and operating costs required for their implementation in beef cattle production systems (Whitlow et al., 1976). Most liquid supplements use molasses as a base, and may contain CP as non-protein nitrogen, natural protein, vitamins, minerals and(or) growth promotants. Liquid supplements can be fed in amounts that allow for ad libitum consumption and may prove more profitable than dry supplements under pasture conditions (Grelan and Pearson, 1977). Lick wheel feeders are a common method of delivering molasses-based liquid supplements to beef cattle on pasture. The use of lick wheel feeders allow for less feeder space required per animal than in interval feeding in open troughs (Whitlow et al., 1976). In many situations, however, over-consumption of liquid feed is a problem for beef cattle producers. Some technologies now exist and have been employed to limit and(or) regulate
322
consumption of liquid supplements (Bowman et al., 1999). This experiment was designed to investigate the effects of reducing feeder lick wheel surface area, restricting lick wheel turning capability, and doing both in combination on liquid supplement intake and variation in intake of yearling beef heifers.
Davis et al.
University of Florida Animal Care and Use Committee (#A551). Animals. Forty yearling heifers (Brangus-crossbred at Gainesville and Braford at Ona; 273 to 386 kg BW) were assigned at random to four bahiagrass (Paspalum notatum) pastures at two Florida locations (five heifers/pasture; 1.62 ha at Gainesville; 1.21 ha at Ona). All heifers received routine health management, which included dewThis experiment was conducted at orming and vaccination for the University of Florida, Santa Fe clostridial and respiratory diseases, Beef Unit, located in Alachua County, pasturella, leptospirosis, and vibriofor 84 d (July 6 to September 28 and sis. at the University of Florida Range Diets and Feeding Procedures. Cattle Research and Education Treatments and pastures were arCenter, Ona, for 84 d (July 13 to ranged in 4 x 4 Latin square design October 10). All procedures for this balanced for carryover effects experiment were approved by the (Cochran and Cox, 1956). Each of the four periods was 21 d in length. Molasses-based liquid supplement (Suga-Lik #500; United States Sugar Corporation, Clewiston, FL [Table 1]) TABLE 1. Composition of basal was offered in amounts sufficient to molasses supplement1, 2. ensure ad libitum consumption using Item Amount, % (± SD) 288-kg capacity commercial liquid supplement feeders with one lick wheel per feeder (RMI, Inc., Bartow, FL). The wheel was either standard DM 72.78 ± 0.34 width (5.1 cm) or narrowed to 1.9 CP 17.03 ± 1.39 cm. Moreover, each wheel width Total sugars as inverts 41.09 ± 1.14 also was evaluated with nonrePhosphorus 0.62 ± 0.02 Potassium 4.01 ± 0.15 stricted, normal, continuous turning Calcium 0.79 ± 0.04 capability) compared with an added Sulfur 0.73 ± 0.05 device, which restricted the wheel Sodium 0.12 ± 0.03 from making a full rotation. The standard width, non-restricted wheel 1Liquid feed (Suga-Lik #500, United (S-NR) feeder served as the control. States Sugar Corporation, Clewiston, Restricted wheels were developed by FL) samples collected weekly during inserting a 15.2-cm carriage bolt both experiments and at each through a wheel spoke near the location. Values represent means of licking surface in order to restrict composited weekly samples. turning to approximately 330° in one 2Free-choice mineral mix in addition direction. Therefore, the three to liquid supplement contained 17% treatments were standard width, Ca and 9% P as calcium carbonate, turning restricted (S-R); narrow monocalcium phosphate and width, non-restricted turning (N-NR); dicalcium phosphate, 25% salt as sodium chloride, 0.25% Mg as and narrow width, restricted turning magnesium oxide, 0.15% Cu as (N-R). copper sulfate, 0.01% Co as cobalt Liquid supplements were added to sulfate, 0.01% I as calcium iodate, feeders on Monday of each week and 0.20% Mn as manganous sulfate, replenished on other days as neces0.0040% Se as sodium selenite, and sary. Liquid supplement consump0.40% Zn as zinc sulfate. tion was recorded at each offering by weighing the feeders before and after
Materials and Methods
addition of supplement using a spring dial scale. Supplement consumption was calculated for each week during the 3-wk periods. Administration of Dual Marker System. During periods 3 and 4, heifers on S-NR and N-R treatments were administered a Captec Crsesquioxide bolus (Nufarm Limited, Auckland, New Zealand). The ability to include all treatments was limited due to the cost of reagents; therefore, the treatment with the greatest amount of restriction (NW-R) was compared with the standard device (S-NR). This was done in order to estimate total fecal output for the estimation of individual liquid supplement intake. Additionally, Ybchloride solution (Rhodia Inc., Phoenix, AZ) was added to the liquid supplements at a calculated concentration of 340 ppm Yb. This concentration was chosen to allow for analysis and detection of liquid supplement intake to 0.11 kg/d, based on expected detection limits of Yb and estimated quantities of feces. The Yb-chloride solution was diluted with distilled, deionized water, so that a field level of 2 mL was added to 0.454 kg of liquid supplement to attain the 340 ppm Yb in the liquid supplements. The solution was then mixed thoroughly into the liquid supplement using a cordless electric drill with a paint stirring attachment. Sampling and Data Collection. Liquid supplement that was left in the feeder and liquid supplement after addition and blending were sampled weekly. Fecal grab samples were taken from the rectum on four occasions between d 10 and 21 of periods 3 and 4 for all heifers on SNR and N-R treatments. Laboratory Analyses. Liquid supplement was composited by period and analyzed for DM, CP, total sugars as inverts, Ca, P, K, S, and Na. Dry matter was determined by vacuum over sand drying, CP by Kjeldahl N determination (AOAC, 1990), total sugars as inverts by gravimetric Munson-Walker method (Browne and Zerban, 1941), and minerals by inductively coupled
CASE STUDY: Liquid Feed Intake
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University of Florida-IFAS Analytical Research Laboratory for Yb concentration using ICP (Spectro Ciros Model FTCEA000, Spectro Co., Lick wheel treatment Fitchburg, MA) according to Fassel (1978). Item S-NR1 S-R2 NW-NR3 NW-R4 Period Avg Liquid supplement samples from SNR and N-R treatments, taken during the week that fecal sampling ocPeriod Intake, kg/head daily curred, were prepared and analyzed 1 2.25 1.15 2.03 0.50 1.48 for Yb using the previously described 2 1.84 1.99 2.32 1.43 1.90 methods. The actual Yb concentra3 3.02 2.69 2.02 1.63 2.34 tions in liquid supplements were 4 3.57 2.20 2.46 2.82 2.76 used in the equation to estimate Avg 2.67a 2.00b 2.21b 1.60c 2.12 liquid supplement consumption by individual animals. For fecal Cr 15.1-cm wide lick wheel, unrestricted rotation. analysis, a 1-g subsample of ground 25.1-cm wide lick wheel, wheel rotation restricted to ~330°. feces was ashed for 1.5 h at 600°C, 31.9-cm wide lick wheel, unrestricted rotation. and the ash was prepared according 41.9-cm wide lick wheel, wheel rotation restricted to ~330°. to the procedure described by Willa,b,cAverage intakes lacking a common superscript differ (P<0.05); SE = 0.27. iams et al. (1962). Fecal Cr concentration was determined using the Perkin-Elmer model 5000 atomic plasma emission spectroscopy (ICP). beaker at 500°C for 8 h. Ash was absorption spectrophotometer These analyses were conducted at the recovered in 20 mL of a 0.1-M (Perkin-Elmer, Norwalk, CT). Fecal laboratory of United States Sugar solution of output estimates were calculated Corporation Laboratory (Clewiston, diethylenetriaminepentaacetic acid using fecal Cr concentration and the FL). in 0.3 N NaOH with 0.1% K. The daily Cr release from the bolus. Fecal samples were dried in a solution was extracted for 12 h on a The daily release rate of Cr from forced-air oven at 100°C for 24 h and shaking device and then filtered. The the Captec was validated using six crossbred beef steers (227 kg BW, 1.5 ground in a Wiley mill to pass a 1procedure is described by Ellis et al. yr) in metabolism stalls at the Ona mm screen. After grinding, a 1-g (1982). The final extraction was subsample was ashed in a 50-mL submitted in scintillation vials to the location. Steers were offered bahiagrass hay ad libitum to allow for refusal and to determine accurate DM intake. Bahiagrass hay offered and TABLE 3. Effect of feeder wheel width and rotation restriction on freerefused was recorded daily. Each choice consumption—Ona. steer was dosed with one Captec bolus on d 1, and total feces were Lick wheel treatment collected for 21 d during September 2000. All feces were collected in Item S-NR1 S-R2 NW-NR3 NW-R4 Period Avg galvanized steel pans and weighed daily. Feces were thoroughly mixed, and a subsample was taken and dried Intake, kg/head daily Period in a forced-air oven to determine 1 3.25 2.53 3.31 1.12 2.55 DM. Fecal samples from each animal 2 3.00 3.41 3.31 3.05 3.19 collected on d 8 through 16 were 3 2.95 3.63 3.00 2.75 3.08 4 3.14 2.55 4.02 2.62 3.08 analyzed for Cr concentration using Avg 3.08a 3.03a 3.41a 2.38b 2.98 the methods as previously described. It was determined that each bolus 15.1-cm wide lick wheel, unrestricted rotation. had a Cr release of 0.99 g/d, used to 25.1-cm wide lick wheel, wheel rotation restricted to ~330°. estimate fecal DM output with the following equation from Earley et al. 31.9-cm wide lick wheel, unrestricted rotation. (1999): Fecal DM output (g/d) = (Cr 41.9-cm wide lick wheel, wheel rotation restricted to ~330°. intake, g/d) / (fecal Cr concentration, a,b,cAverage intakes lacking a common superscript differ (P<0.05); SE = 0.27. g/g DM). Individual animal daily liquid supplement consumption was
TABLE 2. Effect of feeder wheel width and rotation restriction on freechoice consumption—Gainesville.
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estimated using daily fecal DM, fecal Yb concentration, and Yb concentration of liquid supplement in the following equation from Earley et al. (1999): Supplement intake (g/d) = (fecal Yb concentration, g/g * fecal output, g/d) / supplement Yb concentration (g/g). Individual heifer intake was averaged by period for each pasture, and a CV was calculated. The CV was determined by dividing the SE by the mean for each pasture. Statistical Analyses. Treatment, pasture, and period data obtained from the 4 x 4 Latin square design were subjected to the GLM procedure of SAS (1985). The interaction of treatment x pasture x period was chosen as the error term. Least squares means were separated when F-test was significant (P< 0.05).
Results and Discussion Liquid supplement intakes for the wheel width and restriction trials at Gainesville and Ona are summarized in Tables 2 and 3. At Gainesville, daily supplement consumption was reduced (P<0.01) by 25%, to 2.00 kg/ d by restriction of the standard wheel width (S-R) compared to the unrestricted standard wheel (S-NR; 2.67 kg/d). Reducing wheel width to 1.9 cm (NW-NR) reduced (P<0.02) consumption by 17%, to 2.21 kg/d. There was no significant difference between S-R and NW-NR. At the Gainesville location, narrow width with restricted turning lowered (P<0.001) consumption by 40% to 1.60 kg/d. At the Ona location, rotation restriction of a standard width lick wheel (S-R) resulted in daily consumption similar to control (P=0.79). Reducing the wheel width to 1.9 cm also did not significantly reduce consumption (P=0.12). The most effective treatment for lessening intake was narrowing and restricting rotation of the lick wheel (NW-R). The NW-R treatment gave a 23% decline (P<0.01) in consumption to 2.38 kg/d. Although not well documented, the physical manipulation of feeding devices is commonplace
Davis et al.
within the livestock-producing community. McLennan et al. (1991) compared consumptions of molassesurea liquid supplement delivered in a lick tank with a lick-wheel device similar to the current study. Supplement intake from this system was compared with an open trough feeder. The use of the lick-wheel feeder provided a significant reduction in supplement consumption. Nolan et al. (1975) experimented with physical means of limiting liquid supplement intake. A waximpregnated wooded raft was floated on liquid supplement in an open trough in attempt to limit consumption. Tritiated water was used to measure intake and a CV of 52% was reported. The scientific literature is limited on this subject, and it becomes difficult to determine whether these results are within normal ranges. Most studies in this area have dealt with comparisons of trough space per animal, supplement amount, supplement form, and group vs. individual feeding. At Gainesville, the CV for supplement intake on the standard, unrestricted wheel was greater (26%; mean intake 2.67 kg/d) than the narrowed, restricted wheel (15%; mean intake 1.60 kg/d). In contrast, the narrowed, restricted wheel at Ona provided more variation in intake (35%; mean intake 2.38 kg/d) compared with the standard, unrestricted wheel (23%; mean intake 3.08 kg/d). The CV for both treatments at Gainesville (26 and 15%) and the narrowed, restricted wheel at Ona (23%) were less than 107% CV for molasses-urea supplements reported by Bowman et al. (1995b) and 37% CV reported by Langlands and Donald (1978). The variation values also were less than those reported by Webb et al. (1973), Nolan et al. (1975), Llewelyn et al. (similar to Ona; 1978), and Mulholland and Coombe (1979), who reported CV of 46, 52, 23, and 64%, respectively. Previous research (Wagnon, 1966) illustrated that social dominance and social interactions play an important role in feeding behaviors and supple-
ment consumption. This is most apparent in herds with mixed ages and sizes of animals. Bowman et al. (1995a) observed that 2-yr-old cows consumed less liquid supplement from lick tanks than 3-yr-old cows on November range in Montana. The animals used in these trials were very similar in age, size, and breed type. Thus, the variation in supplement consumption is more likely due to feeding behavior, individual animal preferences, and nutritional needs. Technologies now exist and have been employed to limit consumption of liquid supplements by grazing ruminants. Lick feeders capable of dispensing predetermined, programmed quantities of supplement from a main tank into auxiliary feeding tubs using a metered gravity flow system are now available (Bowman et al., 1995a). This is being done in an effort to control more closely individual animal consumption, and it complements the objectives of this research. The effectiveness of these delivery systems was reported by Bowman et al. (1999).
Implications Physical manipulation of feeder lick wheels appears to be an effective means of limiting liquid supplement intake for beef heifers on pasture. Results from these experiments indicate that reducing the surface area of the lick wheel in combination with restricted rotation is most effective. This is a relatively simple technology that could be implemented by the supplement feeder industry with little additional cost to the livestock producer.
Acknowledgments Appreciation is extended to the Liquid Feed Committee of the American Feed Industry Association for their partial financial support of this research, the United States Sugar Corporation (Clewiston, FL) for the donation of liquid feed, and RMI, Inc. for their donation of supplement feeders. Appreciation is also ex-
CASE STUDY: Liquid Feed Intake
tended to Carol Piacitelli, Toni Wood, Charles Stevens, Bert Faircloth, Steve Chandler, and Angelita Mariano for their technical assistance during the conduct of these studies. The authors are also grateful to graduate students Bradley Austin and Edgar Rodriguez for their help in sample and data collection.
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Literature Cited AOAC. 1990. Official Methods of Analysis (15th Ed.). Association of Official Analytical Chemists, Washington, DC Bowman, J. P. G., B. F. Sowell, and D. L. Boss. 1995a. Effect of liquid supplement delivery method on forage intake and digestibility by cows on native range. Proc. West. Sect. Am. Soc. Anim. Sci. 46:391. Bowman, J. P. G., B. F. Sowell, D. L. Boss, and H. Sherwood. 1999. Influence of liquid supplement delivery method on forage and supplement intake by grazing beef cows. Anim. Feed Sci. Technol. 78:273. Bowman, J. P. G., B. F. Sowell, and J. A. Paterson. 1995b. Liquid supplementation for ruminants fed low-quality forage diets: A review. Anim. Feed Sci. Technol. 55:105.
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