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ANIMAL NUTRITION |
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* Department of Animal and Food Sciences and
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Department of Range, Wildlife, and Fisheries Management, Texas Tech University, Lubbock 79409;
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National Animal Disease Center, USDA-ARS, Ames, IA 50010; and
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Department of Cell Biology and Biochemistry, Texas Tech University Health Science Center, Lubbock 79409
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Abstract |
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 Top Abstract IntroductionMaterials and MethodsResultsDiscussionImplicationsLiterature Cited |
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Key Words: Beef Cattle • Calcium • Fattening Performance • Phosphorus • Vitamin D
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Introduction |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionImplicationsLiterature Cited |
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; Horst, 1986; Hurwitz, 1996). The major effect of supplementing high levels of VITD is an increase Ca absorption and the release of Ca from bone stores (Conrad and Hansard, 1957; Littledike and Goff, 1987). Supplementing VITD shortly before slaughter to improve meat tenderness has received considerable attention recently. Swanek et al. (1999) first reported that supplementation of VITD improved beef tenderness. Vitamin D3 feeding increases plasma concentrations of Ca, and seems to activate the calpain system. Feeding high levels of VITD (0.5 to 7.5 x 106) IU/(animal•d) for 4 to 10 d before slaughter has improved beef tenderness (Swanek et al., 1999; Montgomery et al., 2000, 2002).
There are a number of pitfalls with VITD supplementation that must be solved before the beef industry can effectively use this technology. Depending on the dose and length of the feeding period, feeding high doses of VITD can induce toxicity, prolonged hypercalcemia, BW loss, loss of appetite, decreased feed intake, and even death (Littledike and Horst, 1982; Mortensen et al., 1993). Thus, supplementing livestock with VITD to improve tenderness has resulted in decreased feed intake and performance (Enright et al., 1998, 2000; Karges et al., 1998; Montgomery et al., 2002).
Several studies have shown that VITD supplementation had minimal to no effects on tenderness (Hill et al., 1999; Rider et al., 2000; Scanga et al., 2001), which suggests the need for further research. Our objectives were to determine the effects of biological type of cattle and different supplemental doses of VITD on the feedlot performance, plasma Ca and P concentrations, and carcass traits of feedlot steers. Additional results on the tenderness of different muscles and biochemical effects are detailed in other publications (Montgomery et al., 2004a,b).
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Materials and Methods |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionImplicationsLiterature Cited |
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The lightest and heaviest steers of each biological type were designated as extra steers and were not used in the experiment. The remaining 144 steers were split into the three respective breed types, and within each biological type, steers were stratified by initial BW and assigned randomly within BW strata to one of the four dietary vitamin D3 treatments. During the next 14 d, the diet was gradually stepped up to a 90% concentrate diet. Within 14 d of initial processing, each steer was again individually weighed, implanted with Ralgro (Schering-Plough Animal Health, Kenilworth, NJ), and sorted to a newly assigned pen (d 1 of the study). Six steers of the same biological type were stratified by weight to one partially slotted concrete floor pens. Each steer was again individually weighed unshrunk on d 57, 99, and 123 of the study.
Diet
Ingredient composition of the 90% concentrate diet that was fed through the study is shown in Table 1, and the nutrient composition of the diet is shown in Table 2. The diet was mixed in a 1.27-m3 capacity paddle mixer. The Burnett Center feed milling system is operated by a computer-controlled batching system. Once the total diet was mixed, the amount of feed allotted to each pen was delivered to individual pens using a computer-controlled, belt-feeding system. Each feed bunk was evaluated visually at approximately 0700 to 0730 daily. The quantity of feed remaining in each bunk was estimated, and the daily allotment of feed for each pen was recorded. This bunk-reading process was designed to allow for little or no accumulation of unconsumed feed (0 to 0.5 kg/pen). Feed bunks were cleaned, and unconsumed feed was weighed on scheduled weigh days. Dry matter content of bunk orts samples were determined in a forced-air oven by drying overnight at 100°C. Bunk orts and DM determinations of weekly feed bunk samples were used to calculate DMI per pen.
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Experimental Vitamin D3 Diets
As noted previously, steers in all pens were weighed after 99 d on feed. Based on this BW measurement, steers were allotted into final study pens of three steers each (n = 48 pens) on d 100; this was accomplished by pulling cattle evenly from across the BW strata to fill pens. Before the dietary treatment period, two steers were removed from the experiment because of leg injuries (142 steers remained). The dietary treatments consisted of 0, 0.5, 1.0, or 5.0 x 106 IU/(steer•(d) of VITD (Roche Vitamins Inc., Nutley, NJ) during the last 8 d of feeding (study d 116 to 123). Four pens of each biological type received one of the four VITD treatments for the last 8 d of feeding (d 116 through 123 of the study). The VITD was individually weighed per pen each day and diluted in 100 g of ground cornmeal. For each pen, treatments were top dressed on the delivered feed and then hand mixed immediately after delivery to each feed bunk. Before feeding during the last 8 d of feeding, each bunk was cleaned and any leftover feed from the previous day was collected and weighed as described previously. At study d 123, each steer was again individually weighed, and on d 124 of the study, all cattle were transported to the Excel Corp. facility in Plainview, TX.
Plasma Calcium and Phosphorus Determinations
Blood samples were collected from each steer at the time the cattle were weighed on d 99. The blood samples were collected via jugular puncture into 13- x 100-mm, sodium heparin (143 USP units) 10-mL Vacutainer (Becton Dikinson, Franklin Lakes, NJ) tubes. Blood samples were also collected from half the animals on d 119 of the study (after 4 d of VITD supplementation) and from the other half on d 121 (6 d of VITD treatment), and again from each steer at the time of exsanguination (d 124). Blood samples were stored on ice and transported to the Meat Science and Muscle Biology Laboratory at Texas Tech University, where the tubes were centrifuged for 15 min at 500 x g. Plasma was collected from the centrifuged tubes and stored in 4-mL cryotubes at –20°C. Ionized Ca2+ concentrations were determined in duplicate by atomic absorption spectrometry according to Perkin-Elmer Corp. (1965) using standards of 0, 5, 10, and 15 mg of Ca2+/100 mL on a Perkin Elmer model 2380 atomic absorption spectrometer (Perkin Elmer Inc., Wellesley, MA). Plasma P concentrations were determined according to the methods of Parekh and Jung (1970), using a Thermomax microplate reader (Molecular Devices, Sunnyvale, CA).
Slaughter and Carcass Evaluation
As noted previously, after 8 d of VITD supplementation, the steers were transported to Plainview, TX, and slaughtered using approved humane techniques. Blood was collected from each steer during exsanguination. Carcass LM pH was measured with a model 230A Orion temperature-compensated pH meter (Orion Research, Boston, MA) between the 11th and 12th ribs at 3 and 24 h postmortem. Carcass LM temperature also was measured at 3 and 24 h postmortem using a Hantover model TM99A-H digital thermometer (Hantover, Middlefield, CT). Hot carcass weight also was collected at slaughter.
Carcasses were spray-chilled for 48 h (–1°C). After chilling, they were ribbed at the 12th rib, and USDA quality and yield grade traits were recorded. Carcasses were evaluated for percentage of kidney, pelvic, and heart fat, fat thickness at the 12th rib, LM area, USDA yield grade, marbling score, skeletal maturity, lean maturity, overall maturity, USDA quality grade, lean color, lean texture, lean firmness, heat ring, and the incidence of dark cutting beef (USDA, 1989). Dressing percent and yield grades were calculated.
Commission Internationale de l’Eclairage L* (muscle lightness), a* (muscle redness), b* (muscle yellowness), saturation index, and hue angle values were collected from the LM of each carcass between the 12th and 13th ribs with a Hunter Miniscan XE Plus spectrometer (Reston, VA) using illuminant D65 and a 3.5-cm aperture. Two readings were taken and averaged for each carcass. The percentages of myoglobin, oxymyoglobin, and metmyoglobin were calculated using the specific-wavelength method as described by Krzywicki (1979).
Statistical Analyses
Feedlot performance data, carcass traits, and plasma Ca and P concentrations were analyzed using a 4 (VITD treatment) x 3 (biological type) factorial arrangement of treatments in a completely random design, where a pen of three steers was the experimental unit. Feed intake data were analyzed as a repeated measure, and the main plot consisted of the VITD and breed type main effects and the VITD x biological type interaction. The error term for the main plot was VITD x biological type nested within pen (the average pen-to-pen value within a biological type x vitamin D concentration combination). For the subplot, the repeated measure was day (the 8 d of vitamin D supplementation), and all interactions were represented. For all analyses, the experimental unit was a pen of steers, with an 
level of 5%. Data for the 4 x 3 factorial were analyzed according to Steel and Torrie (1980), and least squares means were calculated using the GLM procedure of SAS (SAS Inst., Inc., Cary, NC). Differences among treatment means were determined using the PDIFF option of SAS. When data were analyzed as a repeated-measures (split-plot) design, the pooled standard errors were calculated according to Steel and Torrie (1980) and means were separated with the LSD method. Critical differences were calculated for the LSD by calculating the Saiterthwaite degrees of freedom for the t-values (Saiterthwaite, 1946). Because there was a VITD treatment difference (P < 0.05) in initial ADG, initial ADG was used as a covariate in the analysis of the final (last 24 d of the feeding period) ADG. Linear and quadratic affects of VITD treatment on feedlot performance, plasma Ca and P concentrations at slaughter, and carcass traits also were tested using orthogonal contrasts.
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Results |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionImplicationsLiterature Cited |
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. Initial BW, final BW, and average daily DMI were not affected by VITD treatments (P = 0.21). Average daily gain was measured throughout the 123-d feeding period, including the first 99 d on feed and the last 24 d on feed. By chance, effects for initial ADG measured during the first 99 d indicated a significant VITD effect (P = 0.02), even though VITD was not supplemented until the last 8 d on feed. Specifically, initial ADG was greater for the 1 x 106 IU/(steer•d) VITD treatment than for other treatments, and as noted previously, initial ADG was used as a covariate for subsequent analyses. There was a linear decrease (P = 0.002) in ADG due to feeding VITD, and ADG during the last 24 d of feeding was decreased (P = 0.04) when steers were fed 5 million IU of VITD daily (Table 3). Although overall DMI for the final 24 d of the feeding period was not affected by VITD treatment, feeding 5 million IU of VITD/(steer•d) daily decreased (P < 0.01) DMI on d 5, 7, and 8 of the VITD feeding period (d 120, 122, and 123 of the study; Figure 1). There was a linear decrease (P = 0.003) in G:F as a result of VITD treatment, and feeding 5 million IU of VITD/(steer•d) daily decreased (P < 0.05) G:F compared with controls steers and steers supplemented 0.5 million IU of VITD/(steer•d) daily. Therefore, supplementing cattle with 5 million IU/(steer•d) over eight consecutive days decreased ADG and G:F, but other VITD levels did not affect (P < 0.07) these performance measurements.
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) compared with controls. Feeding 1 million IU of VITD/d increased (P < 0.05) Ca plasma concentrations compared with controls only at slaughter, and plasma Ca and P concentrations were not affected by the 0.5 million IU of VITD treatment. Similar to plasma Ca, treating steers with VITD resulted in a linear increase (P < 0.001) in plasma P concentrations at slaughter. At 1 and 5 million IU/(steer•d), VITD increased (P < 0.05) plasma P concentrations at d 6 of supplementation and at slaughter (Figure 3) compared with controls. Overall, it is evident that supplemental VITD at 5 million IU/(steer•d) had the greatest effect on increasing plasma Ca2+ and P compared with the other VITD treatments (Figures 2 and 3, respectively).
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) were minimal, and VITD treatment did not interact (P = 0.054) with biological type for any of the carcass traits tested. The USDA quality and yield factors and color variables were not generally affected by VITD supplementation, suggesting that improvements in beef tenderness as a result of VITD supplementation (Montgomery et al., 2004a) can be made without adversely affecting economically important carcass traits. Testing the carcass traits for linear and quadratic effects of VITD supplementation resulted in only three significant effects: there was a linear increase (P = 0.015) in fat thickness as a result of VITD treatment and a quadratic increase (P < 0.001) of LM temperature at 3 h postmortem and LM pH at 24 h postmortem. Overall, the steers used in this experiment graded 69% Choice or greater (data not shown) and did not show (P = 0.88) any evidence of bone discoloration at 48-h postmortem (data not shown). There was a quadratic increase (P < 0.001) in 24-h LM pH and 3-h carcass LM temperature. Specifically, 24-h LM pH and 3-h carcass temperature were increased (P < 0.05) by all VITD treatments (Table 3
) compared with controls.
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. Dressing percent was increased (P < 0.05) in Bos taurus-Continental steers compared with Bos indicus steers. The color factor, hue angle, was slightly increased (P < 0.05) in Bos taurus-Continental steers compared with Bos taurus-English steers, indicative of a redder, less brown lean color. Bos taurus-English carcasses also had increased (P < 0.05) percentages of myoglobin compared with the other two biological types. Marbling scores were increased (P < 0.05) in Bos taurus-English carcasses compared with Bos taurus-Continental or Bos indicus carcasses (Small vs. Slight marbling). Additionally, quality grades were greater (P < 0.05) in Bos taurus-English carcasses than in Bos taurus-Continental or Bos indicus carcasses (Low Choice vs. High Select). Fat thickness and adjusted preliminary yield grade were decreased (P < 0.05) in Bos taurus-Continental carcasses compared with the other two biological types. Longissimus muscle area also was increased (P < 0.05) in Bos taurus-Continental carcasses compared with the other two biological types. All three biological types differed (P < 0.05) in yield grade, with Bos indicus being the greatest, Bos taurus-English carcasses intermediate, and Bos taurus-Continental carcass having the lowest yield grade.
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Discussion |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionImplicationsLiterature Cited |
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; Hurwitz, 1996). The longer cattle were supplemented or the higher the dose, the greater the effect on Ca and DMI. Early studies with VITD in cattle indicated that supplementation at levels as low as 1 x 106 IU/d increased blood Ca and P and decreased the incidence of milk fever (parturient paresis) in dairy cows (Hibbs et al., 1946, 1951; Hibbs and Pounden, 1955). However, feeding as little as 2.5 x 105 IU/d of VITD for extended periods of time increased plasma concentrations of Ca (McDermott et al., 1985).
Depending on the dose and length of feeding, feeding high doses of VITD can cause VITD toxicity in cattle. Specifically, VITD can result in prolonged hypercalcemia, weight loss, loss of appetite, decreased feed intake, and death (Littledike and Horst, 1982; Mortensen et al., 1993). Puls (1994) suggested that supplementing cattle with 1 to 2 million IU of VITD/d could result in toxicity. In an experiment using the rat as a model, Beckman et al. (1995) reported that supplementing excessive VITD increased expression of the vitamin D receptor, and increased concentrations of plasma Ca2+ and decreased levels of 1,25-(OH)2 D3. Injections of the vitamin D metabolites 25-hydroxyvitamin D3 and 1,25-(OH)2 D3 also have been shown to increase serum Ca concentrations (Hollis et al., 1977; Hove et al., 1983; Hodnett et al., 1992). Therefore, supplementing a moderate concentration of VITD for an extended period of time or a high concentration (e.g., 5 x 106 IU/d) for a relatively short period of time has the possibility of negatively affecting feedlot performance.
Vitamin D3 supplementation did not affect any quality or yield grade factors, which means producers could feed certain levels of VITD (e.g., 0.5 million IU/d) to improve beef tenderness (Montgomery et al., 2004a) without negatively affecting economically important traits such as USDA quality and yield grades and feedlot performance. Because of the possible negative effects on feed intake, ADG, and G:F during long-term high level supplementation of VITD, hot carcass weights could be negatively affected by VITD treatment. Karges et al. (1999) reported that VITD supplementation decreased hot carcass weights when the cattle were fed 6 x 106 IU/(animal•d) for 4 or 6 d, which was likely a result of the decreased feed intake and growth that has been previously noted (Karges et al., 1998; Boleman et al., 2001; Montgomery et al., 2002). In the current study, supplementing 5 million IU of VITD/d decreased ADG 0.37 kg/d compared with controls, and supplementing steers with1 million IU of VITD/d decreased ADG 0.17 kg/d compared with controls. Likewise, we found that feeding 5 million IU/(steer•d) of VITD decreased DMI on d 5, 7 and 8 of supplementation. Feeding a higher dose or increasing the length of the VITD feeding period would likely have increased the intensity of this response.
Because Ca is a powerful primary and second messenger, it is possible that the effects of VITD supplementation on carcass LM pH and temperature resulted from increased cellular metabolism and glycogen modulation. Vitamin D effects on carcass LM pH and temperature might also be a result of metabolism differences leading to increased muscle degradation and improved tenderness. Wiegand et al. (2002) reported increased drip loss of pork carcasses and improved pork-loin chop color from pigs supplemented with VITD, both potentially a result of the pH changes in muscle noted in the current study. In our previous experiment, we noted that 24-h carcass temperature was increased due to VITD treatments of 1.0 million IU or greater (Montgomery et al., 2002); however, carcass pH was not affected by VITD treatments.
Karges et al. (1999) reported that VITD supplementation decreased the Warner-Bratzler shear force, but hot carcass weights were decreased when the cattle were fed 6 x 106 IU/animal daily for 4 or 6 d before slaughter. As noted previously, this decrease in hot carcass weight was probably a result of decreased feed intake and growth (Karges et al., 1998; Montgomery et al., 2002). In the current study, neither hot carcass weight nor dressing percent was adversely affected by any of the VITD treatments. Even though the current study indicated that feeding high levels of VITD has the potential to negatively affect growth and feed intake, Montgomery et al. (2002) reported that feeding less than 2.5 x 106 IU/(animal•d) for 9 d before slaughter did not negatively affect feed intake by steers. Scanga et al. (2001) reported that supplementing heifers with 1 x 106 IU/d of VITD decreased appetite and feed intake. Although further research is needed, a VITD dose level of 0.5 x 106 IU/(animal•d) does not seem to decrease important economic growth performance traits of beef cattle. Therefore, the results from the present research show that cattle can be supplemented with 0.5 million IU of VITD/(steer•d) to improve beef tenderness without adversely affecting feedlot performance and carcass traits.
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Implications |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionImplicationsLiterature Cited |
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Footnotes |
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2 Current address: Intervet Inc., 29160 Intervet Lane, Millsboro, DE 19966.
3 Current address: Meridian Bioscience, Inc., 3471 River Hills Dr., Cincinnati, OH 45244.
4 Correspondence: Box 42162 (phone: 806-742-2804; fax: 806-742-0169; e-mail: mfmrraider{at}aol.com).
Received for publication October 6, 2003. Accepted for publication April 5, 2004.
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Literature Cited |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionImplicationsLiterature Cited |
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-Hydroxyvitamin D3 plus 25-hydroxdroxyvitamin D3 reduces parturient paresis in dairy cows fed high dietary calcium. J. Dairy Sci. 75:485–491.[Abstract]
-hydroxyvitamin D3, 1,25-dihydroxyvitamin D3, 1,24,25-trihydroxyvitamin D3, and 1,25,26-trihydroxyvitamin D3 on mineral metabolism and 1,25-dihydroxyvitamin D concentration in dairy cows. J. Dairy Sci. 66:59–66.This article has been cited by other articles:
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  J. D. Rivera, S. E. Bachman, M. E. Hubbert, M. E. Branine, R. L. Horst, S. N. Williams, and M. L. Galyean Short Communication: Serum and Tissue Concentrations of Vitamin D Metabolites in Beef Heifers After Buccal Dosing of 25-Hydroxyvitamin D3 J Dairy Sci, April 1, 2005; 88(4): 1364 - 1369. [Abstract] [Full Text] [PDF]
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 J. L. Montgomery, J. R. Blanton Jr., R. L. Horst, M. L. Galyean, K. J. Morrow Jr., V. G. Allen, D. B. Wester, and M. F. Miller Effect of supplemental vitamin D3 concentration on concentrations of calcium, phosphorus, and magnesium relative to protein in subcellular components of the longissimus and the distribution of calcium within longissimus muscle of beef steers J Anim Sci, September 1, 2004; 82(9): 2742 - 2749. [Abstract] [Full Text] [PDF]
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J. L. Montgomery, J. R. Blanton Jr., R. L. Horst, M. L. Galyean, K. J. Morrow Jr., D. B. Wester, and M. F. Miller Effects of biological type of beef steers on vitamin D, calcium, and phosphorus status J Anim Sci, July 1, 2004; 82(7): 2043 - 2049. [Abstract] [Full Text] [PDF]
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J. L. Montgomery, M. B. King, J. G. Gentry, A. R. Barham, B. L. Barham, G. G. Hilton, J. R. Blanton Jr., R. L. Horst, M. L. Galyean, K. J. Morrow Jr., et al. Supplemental vitamin D3 concentration and biological type of steers. II. Tenderness, quality, and residues of beef J Anim Sci, July 1, 2004; 82(7): 2092 - 2104. [Abstract] [Full Text] [PDF]
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