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ANIMAL NUTRITION |
Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506-1600
Abstract
We evaluated the effect of forage quality on response of cattle to supplementation with cooked molasses blocks. In Exp. 1, 175 heifers had ad libitum access to prairie hay (5.2% CP, DM basis). Treatments were a 2 x 3 factorial: supplementation with 0 or 1.96 kg/d of alfalfa DM, and supplementation with no cooked molasses block or with a low-protein or a high-protein cooked molasses block (14.4 and 27.5% CP, respectively, DM basis). There were no significant interactions between alfalfa and cooked molasses block for intake or gain. Forage intake and ADG were increased (P < 0.05) by alfalfa supplementation. Heifers fed high-protein cooked molasses blocks gained more (P < 0.05) weight than those fed low-protein cooked molasses blocks or no cooked molasses block. Heifers fed high-protein cooked molasses blocks ate more (P < 0.05) forage than those fed low-protein cooked molasses blocks, with heifers fed no cooked molasses block being intermediate. In Exp. 2, responses to cooked molasses blocks containing 33% CP (DM basis) were measured in 18 steers fed: 1) brome (8.4% CP), 2) alfalfa (19.2% CP), or 3) brome supplemented with 1.93 kg/d of alfalfa DM. Forages were available ad libitum. Forage DM intake was not affected by cooked molasses block and was greater (P < 0.05) for alfalfa than the alfalfa/brome mix, which in turn was greater (P < 0.05) than brome. Digestibility of DM was greater (P < 0.05) for alfalfa than brome or the alfalfa/brome mix and was not affected by cooked molasses block supplementation. Supplementation with cooked molasses blocks had only small effects on intake and digestion of medium- to high-quality forages, but it improved gains and feed efficiencies of heifers fed prairie hay ad libitum, with or without supplemental alfalfa.
Key Words: Cattle • Cooked Molasses Block • Forage • Supplementation
Introduction
Previous studies have demonstrated that cattle fed low-quality forages (prairie hay containing 5 to 6% CP) respond to supplementation with cooked molasses blocks (CMB) by increasing forage intake and digestion (Greenwood et al., 1998
, 2000; Löest et al., 2001). Much of this response is attributable to the supply of protein, particularly ruminally degradable protein, which has been demonstrated to be the most limiting nutrient under these conditions (Köster et al., 1996). However, higher quality forages typically contain enough protein to meet the degradable protein needs of the ruminal microbes such that response to protein supplementation per se may be limited. Additionally, substitution effects (reductions in forage intake in response to supplement consumption) are usually greater with high-quality forages than with low-quality forages (Hyer et al., 1991), suggesting that increases in forage intake in response to supplementation with CMB may be less likely to occur when high-quality forages are consumed.
The aim of this study was to determine how the quality of forage affects the response of cattle to CMB supplementation, and how much of the response is attributable to the protein supplied by CMB. To accomplish this goal, we evaluated digestion and performance responses of heifers fed prairie hay alone or in combination with alfalfa to supplementation with CMB containing two levels of CP. We also evaluated intake and digestion responses of steers fed medium- to high-quality forages to supplementation with CMB.
Materials and Methods
The Kansas State University Institutional Animal Care and Use Committee approved procedures involving animals in this study.
Experiment 1
One hundred seventy-five British- and Continental-cross beef heifers averaging 310 kg of BW initially were used in a randomized complete block design experiment where forage intake and growth rate were measured. Cattle were housed in 30 concrete-floored pens with each pen (36.5 m2 with 3.5 m of feed bunk) containing five or six heifers. Heifers were grouped based on BW and previous management to generate five replications of six pens each. The six treatments, which were randomly allotted within each of five replications, were arranged in a 2 x 3 factorial with the factors being the basal forage offered to the heifers and CMB supplementation. The forage fed was either 1) prairie hay (5.2% CP and 73% NDF; DM basis) to allow ad libitum access or 2) 1.96 kg/d of alfalfa DM (18.6% CP and 60% NDF; DM basis) plus ad libitum access to prairie hay. Both forages were ground through a 76-mm screen. These treatments represented a poor-quality and an intermediate-quality forage diet for cattle. The CMB supplementation treatments were 1) no CMB, 2) a low-protein CMB analyzed to contain 14.4% CP (DM basis), and 3) a high-protein CMB analyzed to contain 27.5% CP (DM basis). The CMB were packaged in 15-L tubs weighing approximately 20 kg, and they were placed in feed bunks, one per pen, to allow heifers access. All heifers had ad libitum access to white salt blocks and water.
The high-protein CMB was labeled to contain not more than 15% CP from nonprotein N sources. Other label claims included those for Ca (2.0 to 2.5%), P (2.0 to 2.5%), and crude fat (minimum of 5%). The ingredient list was cane molasses, cottonseed meal, hydrolyzed feather meal, hydrolyzed vegetable fat, monocalcium phosphate, dicalcium phosphate, urea, limestone, zinc sulfate, manganese sulfate, copper sulfate, sodium selenite, ethylenediamine dihydriodide, cobalt carbonate, and vitamins A, D3, and E. The low-protein CMB was not labeled to contain nonprotein N sources. Label claims for the low-protein CMB included those for Ca (2.3 to 2.8%), P (2.0 to 2.5%), and crude fat (minimum of 5%). The ingredient list was the same as that for the high-protein CMB except urea was not included.
The study lasted 89 d, and heifers were fed CMB for the final 84 d. Before starting the study, all heifers were fed 2.27 kg/d of alfalfa (as-is) plus ad libitum access to prairie hay. At the initiation of the experiment, heifers were weighed without prior removal of feed and water and were immediately allocated to the treatment forages. Beginning on d 6, heifers were provided ad libitum access to the appropriate CMB. After 14 d of CMB consumption, it became apparent that intake of CMB was much greater than that typical of free-range cattle. Therefore, for the remainder of the experiment, heifers were allowed access to CMB for only 4 h of each day, which led to CMB intakes more typical of free-range cattle.
Heifers were weighed on d 19 and 89. Following completion of the experiment, heifers were transferred to 12 larger soil-surface pens with two or three pens of heifers combined by treatment. Heifers were given ad libitum access to common diets based on steam-flaked corn and alfalfa for 9 d, at which time they were weighed to determine whether some of the treatment effects were due to differences in gut fill.
Digestibilities for complete diets were measured during d 80 to 83 of the trial by cleaning pens and subsequently collecting and weighing total fecal output daily. Samples of feces were collected and frozen pending analysis. Feed bunks were cleaned on d 80, and orts were weighed and sampled on d 83. Forage samples were collected on d 80 to 82 and composited before analysis. Samples of CMB were collected by drilling core samples (25 mm diameter x 80 mm deep). Dry matter of forages, orts, and feces were determined by drying to constant weight at 55°C. Dry matter of CMB samples was determined by drying for 16 h in a vacuum oven at 70°C. By design, digestibilities were measured for only three of the five replicate blocks.
Data were analyzed with ANOVA using the GLM procedure of SAS (SAS Inst., Inc., Cary, NC). Pen was the experimental unit. The model was that for a randomized complete block design and included terms for replicate, forage type, CMB, and the forage x CMB interaction. Means were separated using pairwise t-tests when the F-test was significant (P < 0.05).
Experiment 2
Eighteen British- and Continental-cross steers (282 kg initial BW) were used in an intake and digestion study to evaluate the effects of supplementation with a 33.2% CP CMB at a level of 0.10% of BW. Responses to CMB supplementation were measured for steers fed each of three different forages: 1) brome hay (94.6% OM, 72.9% NDF, and 8.4% CP on DM basis), 2) alfalfa hay (90.2% OM, 51.3% NDF, and 19.1% CP on DM basis), and 3) brome hay supplemented with 1.93 kg/d of alfalfa DM. The brome hay was stored as 40-kg bales and was cut at 10-cm increments with a bale slicer. The alfalfa was chopped through a 76-cm screen.
The CMB was analyzed to contain 33.2% CP, 83.8% OM, and 7.8% NDF on a DM basis, and it was labeled to contain not more than 12% CP from nonprotein N sources. Other label claims included Ca (2.0 to 2.5%), P (2.0% minimum), and crude fat (minimum of 4%). The ingredient list was: molasses products, concentrated separator by-product, animal fat, plant protein products, animal protein products, processed grain by-products, urea, monocalcium phosphate, dicalcium phosphate, calcium carbonate, magnesium oxide, sulfur, zinc sulfate, manganous oxide, ferrous sulfate, copper sulfate, zinc oxide, manganese sulfate, ethylenediamine dihydriodide, cobalt carbonate, calcium iodate, sodium selenite, and vitamins A, D3, and E.
The experimental design was three simultaneous cross-over experiments. Each cross over contained six steers and two periods. Within each cross-over experiment, all six steers received the same forage. In each period, three steers per crossover received CMB supplementation, whereas the other three served as controls. In the second period, CMB supplementation treatments were switched for all steers. Each period was 18 d long with 12 d for adaptation and 6 d for total collection of feces with fecal collection bags. Steers were housed in individual, concrete-floored pens (1.5 x 6.9 m, with 1.4 m feed bunks) with approximately half the pen (as well as the feed bunk) being covered within a barn. Water was available to steers at all times, and plain salt (20 g/d) was provided to each steer daily.
Steers were given 2.27 kg (as-fed basis) of alfalfa or brome hay early in the morning, with the remainder of their forage being provided approximately 4 h later. The CMB were packaged in 19-L tubs and weighed approximately 25 kg initially. Steers were given access to CMB along with the initial forage. The CMB were subsequently removed from the feed bunks after the steers had licked the targeted amount of 0.10% of BW. The process of regulating CMB intake involved determining the weight loss from the CMB at time points expected to result in the targeted intake. If a steer licked too little, either more time was allotted for licking or appropriate quantities of CMB (broken into small pieces) were placed in the feed bunk to meet the steer’s allotment. In cases where steers consumed more than their allocation, no action could be taken, so CMB intakes were occasionally greater than the targeted amount of 0.10% of BW. In cases of CMB overconsumption, the targeted intake for the following day was not altered. In general, steers consumed their CMB within 1 to 2 h. Forages were available ad libitum with the amount offered daily set as 120% of intake from the previous 5 d.
Dry matter intakes were determined in each period by sampling forage offered and collecting orts once daily during d 12 to 17 of each period. Composite samples of forage for each period and composite samples of orts for each steer in each period were dried (55°C) and ground (Wiley mill, 1-mm screen) before analysis. Fecal samples were collected daily for d 13 to 18 of each period, subsampled, composited within steer, dried (55°C), and ground (Wiley mill, 1-mm screen) before analysis. Samples of CMB were collected by drilling a core sample (25 mm diameter x 80 mm deep) from two blocks daily during the 6-d collection period (using different blocks each day). Feed, orts, and feces were analyzed for DM (100°C for 24 h), OM (ashing for 16 h at 450°C), N by Kjeldahl analysis, and NDF using procedure A of Van Soest et al. (1991) without amylase or sulfite. The CMB were analyzed as above except for DM, which was determined by drying for 16 h in a vacuum oven at 70°C.
Passage rate from the rumen was measured using ytterbium (Yb) as a particulate-phase marker. On d 12 of each period, steers were fed 0.45 kg of forage that had been sprayed with 100 mL of a solution containing 3 g of Yb (as YbCl3) and subsequently dried at 38°C. Steers on the alfalfa and brome/alfalfa mix treatments were given the marker on alfalfa, whereas steers on the brome treatments were given the marker on brome. After steers consumed the marked forage, the remainders of their forage allotments were given. At 24, 48, 72, 96, and 120 h after dosing, freshly voided fecal samples were collected, dried (55°C), ground (Wiley mill, 1-mm screen), and analyzed for concentration of Yb by atomic absorption spectrophotometry with an NO2/acetylene flame after ashed residues were solubilized in a solution containing 3 N HCl and 3 N HNO3 (Ellis et al., 1980). The natural logarithm of the Yb concentration was regressed against time for samples collected at 48, 72, 96, and 120 h. In all cases, linear regression of the log-transformed concentrations described the decay curve well. Values from samples collected at 24 h were not used for calculating passage rate because fecal Yb concentrations had not yet reached the apex for approximately two-thirds of the observations.
Data were analyzed with ANOVA using the GLM procedure of SAS. The model included forage, steer within forage, period, CMB treatment, and forage x CMB. Effects of forage were tested using steer within forage as the error term, whereas CMB and forage x CMB were tested against residual error. Means were separated by paired t-tests among all means when the overall F-test was significant (P < 0.05).
Results and Discussion
Experiment 1
Effects of treatments on feed intake and performance are presented in Table 1. There were no significant interactions between forage and CMB supplementation for any of the intake or performance criteria. Supplementation of heifers with alfalfa increased (P < 0.05) ADG, gain efficiency, and forage and total DM intakes. On average, forage DM intake was increased 49% (2.75 kg/d) when 1.96 kg/d alfalfa was provided to the heifers. Part of this increase can be accounted for by the alfalfa itself, but a portion of this increase was due to increases in intake of prairie hay. Gains were increased (P < 0.05) from an average loss of 0.18 kg/d to a gain of 0.43 kg/d when alfalfa was supplemented. Gain efficiencies were increased (P < 0.05) from -0.03 to 0.05 when alfalfa was supplemented.
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). These trends follow the general pattern expected when low- and high-protein supplements are fed to cattle consuming poor-quality (low protein) forages (Greenwood et al., 1998; Olson et al., 1999; Bodine and Purvis, 2003). However, effects of CMB supplementation on forage intakes were not different between the forage treatments. Because protein should have been more limiting without supplemental alfalfa, a greater response to protein level in the CMB was expected in heifers receiving prairie hay as the only forage.
Heifers fed high-protein CMB gained weight faster (P < 0.05) than those fed low-protein CMB (Table 1); those fed low-protein CMB did not gain significantly faster than those receiving no CMB. Efficiencies followed the same pattern as gain in response to CMB supplementation. Different responses to the two CMB can be attributed to the high-protein CMB increasing forage intake, whereas cattle fed the low-protein CMB had decreased forage intake. Some of the difference in response to the different CMB may also be explained by the much poorer gains of heifers fed low-protein CMB during the initial phase of the experiment when CMB intakes were relatively high. It is possible that these heifers would have performed better over the entire trial if CMB intakes had been lower during the early segment of the experiment. During the initial period when CMB were available continuously, CMB intakes were near 0.23% of BW daily. During this initial 19-d period, gains of heifers were numerically lower when they received low-protein CMB than when they received no CMB. However, across then entire trial, gains of heifers receiving low-protein CMB were intermediate to those of heifers receiving no CMB and those receiving high-protein CMB, suggesting that there was benefit to heifers consuming restricted amounts of the low-protein CMB.
The NRC (1996) provided a generalization that microbial CP synthesis in the rumen is 13% of TDN, and it uses this estimate to set the requirement for degradable intake protein (DIP). However, the NRC (1996) also cautioned that the value might be lower when diets are based on poor-quality forages. Data from Köster et al. (1996) demonstrated that intake and digestion of prairie hay was depressed when DIP was less than 11% of digestible OM. Our prairie hay contained approximately 6% of its digestible OM as DIP, assuming CP in prairie hay is 55.5% ruminally degradable (Vanzant et al., 1996). Thus, cattle fed only prairie hay would be expected to respond to supplemental sources of N. However, for supplements to be effective in meeting the needs of the ruminal microbes, they must contain more N than necessary for their own digestion. Given the relatively low N content of the low-protein CMB and its relatively high digestibility, it is likely that this supplement did not contain more DIP than was needed to support its own digestion, and thus was ineffective in improving intake of the prairie hay. In contrast, the high-protein CMB contained more total N that was likely more available in the rumen (due to inclusion of urea), which would allow it to provide DIP in support of forage digestion. The alfalfa hay similarly provided DIP to support the digestion of the prairie hay because it contained DIP equal to 26% of digestible OM, assuming that 83.4% of the alfalfa N was ruminally available (Vanzant et al., 1996) and its digestible OM was 60%. The greater response to alfalfa than to the high-protein CMB can be attributed to the greater intake of the alfalfa.
The alfalfa/prairie hay combination was calculated to contain 11% of its digestible OM as DIP, which is equal to the suggested requirement (Köster et al., 1996). Therefore, responses to protein supplementation from CMB would not be expected to result from improvements in forage digestion for cattle fed the alfalfa/prairie hay mix. However, it is possible that DIP:digestible OM was overestimated for the alfalfa/prairie hay mix, that the optimal DIP concentration for that diet was greater than 11% of digestible OM, or that the observed responses to CMB resulted from the supply of ruminally undegraded protein or another nutrient.
In addition to N, CMB also provide a source of sugar to the ruminal microbes. In general, a large supply of a readily fermentable carbohydrate, such as starch, can reduce intake and digestion of low-quality forages (Olson et al., 1999). Heldt et al. (1999) observed that when DIP was deficient, sucrose additions (0.3% of BW daily) led to numerically lower OM digestibility than similar amounts of starch, but when DIP was adequate there was no difference between starch and sucrose. Cane molasses fed as a relatively large proportion of the diet (15 to 20% on DM basis) decreases fiber digestion from low-quality forages, regardless of N availability (Brown, 1993; Kalmbacher et al., 1995). When fed at levels similar to those in our study (0.125% of BW daily), Greenwood et al. (2000) observed only small differences in digestive responses of cattle fed CMB that contained similar N levels but disparate sugar levels. In that study, CMB, which provided N as well as the sugars, all improved intake and digestion of prairie hay to a similar extent. Thus, the available literature would suggest that in our study, the sugar provided in the CMB was unlikely to be a major contributor to improved forage utilization.
Intakes of CMB were lower (P < 0.05) when heifers were supplemented with alfalfa (Table 1). During the final 70 d when CMB were available to heifers for 4 h daily, CMB were placed in bunks at the same time that alfalfa was provided. However, this does not completely explain differences in CMB intake because the lower CMB intakes for alfalfa-supplemented heifers were observed during the initial period when CMB were available for the entire day as well as during the final 70 d of the experiment when access to CMB was restricted.
In general practice, CMB would be continuously available to grazing animals, and intake of the CMB could occur more than once daily. Additionally, CMB have the potential to alter the grazing behavior of cattle. The issue of feeding frequency is unlikely to be an important variable in our experiment because the supply of supplemental protein seems to be more important than the frequency of intake with regard to utilization of poor-quality forages (Beaty et al., 1994; Bohnert et al., 2002). However, our approach of limiting CMB intake to a single 4-h period each day, as well as the feeding of cattle in a feedlot facility rather than under grazing conditions, could have affected the cattle’s response to the supplements.
Intake of CMB was greater (P < 0.05) for the high-protein CMB than for the low-protein CMB (Table 1). This could reflect a preference for the heifers to consume more of the high-protein CMB or there may have been differences between the blocks in their physical properties, which made consumption of the high-protein block easier for the cattle. Total intake (forage plus CMB) was greatest (P < 0.05) for heifers fed high-protein CMB, and similar between heifers fed low-protein CMB and no CMB. Differences between the CMB treatments in total intake were mostly attributable to differences in forage intake.
Gains of heifers during the 9-d post-trial adaptation period (Table 1) were similar among all treatments, suggesting that gut fill was not a major contributor to differences in gain among the treatments. Thus, although intakes were impacted by treatment, gut fill did not appear to be greatly impacted. In light of the differences in forage intake, particularly in response to alfalfa supplementation, the lack of compensation was somewhat unexpected. This suggests that those treatments that increased intakes did so by increasing either the rate of digestion and/or the rate of passage of digesta from the rumen.
During the digestion portion of this study, forage intakes were increased (P < 0.05) by supplementation with alfalfa (Table 2). However, differences in intake due to CMB supplementation were not significant. Intakes of CMB were lower (P < 0.05) when alfalfa was supplemented. Heifers tended to consume more high-protein CMB than low-protein CMB (P = 0.06). An interaction (P < 0.05) between alfalfa and CMB supplementation was observed for DM digestibilities (Table 2). For heifers not receiving alfalfa, supplementation with either CMB led to increased (P < 0.05) DM digestibility. However, when alfalfa was supplemented, CMB did not significantly affect DM digestibility and actually numerically decreased it. Supplementation with alfalfa led to large increases (P < 0.05) in DM digestibility. Intakes of digestible DM were markedly increased (P < 0.05) by alfalfa supplementation as a result of increases in both intake and digestion. Supplementation with CMB tended to increase digestible DM intake for heifers receiving no alfalfa, whereas this response was not evident for heifers receiving alfalfa (alfalfa x CMB interaction; P = 0.10).
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) may have limited the response in digestibility for the high-protein CMB. It is also possible that nutrients other than DIP supplied by the CMB led to the improvements in digestion. For example, the higher N concentration in the high-protein block was generated by addition of urea, so the availability of true protein would essentially be the same for the two blocks. However, the form of N (i.e., true protein vs. nonprotein N) was not likely an important factor because only 25% of the supplemental DIP needs to be in the form of true protein to optimize digestion of prairie hay diets (Köster et al., 1997).
Experiment 2
Table 3 shows the effects of forage and CMB supplementation on intake and digestion of DM, OM, N, and NDF. Intake of CMB averaged 0.30 kg/d of DM (0.25 kg/d of OM) and was near the target level of 0.10% of BW. Slight differences among forages in CMB intake arose because steers occasionally consumed their CMB faster than expected, but CMB intakes were not statistically different among forages.
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). The CMB did increase (P < 0.05) N digestibility, but this is likely a reflection of extra N intake from the CMB leading to higher apparent digestibilities through dilution of endogenous losses. Assuming that 50% of the N in the brome was ruminally available (Mathis et al., 2000) and that 55% was digestible OM, DIP was approximately 7.5% of digestible OM. Thus, the unsupplemented brome contained less DIP than that predicted to be necessary for optimizing intake and digestion (Köster et al., 1996), although the deficiency of DIP was not as severe as for the prairie hay in Exp. 1. Mathis et al. (2000) observed that cattle fed brome hay containing only 5.9% CP did not exhibit large responses to DIP supplementation. It is possible that the DIP supply from the brome was underestimated or the DIP requirement of 11% of digestible OM overestimates requirements when brome is fed. For cattle fed the mixed forages, DIP represented more than 14% of digestible OM, and this value was even greater for the alfalfa alone (27%). Thus, it is quite clear that for the two diets containing alfalfa, DIP should not have limited forage utilization. The lack of response by cattle to CMB would suggest that the forages used in this experiment were not limiting in DIP and that other components provided by CMB had little effect.
Forage quality was clearly reflected by differences in intake and digestion. For DM, OM, and N, steers fed alfalfa had higher (P < 0.05) intakes and higher (P < 0.05) digestibilities than steers fed brome or the brome/alfalfa mix (Table 3). Intake of NDF and of digestible NDF were not different among the forages, although NDF digestibilities were lower (P < 0.05) for the alfalfa hay than for the brome hay. Digestible OM intake, a measure of energy available to the animal, was 65% greater (P < 0.05) for alfalfa than for the brome hay (4.21 vs. 2.54 kg/d). In general, feeding the brome/alfalfa mix led to intakes and digestibilities that were intermediate to the alfalfa and brome hays alone. The brome/alfalfa mix led to a 22% increase in digestible OM intake relative to brome hay alone (3.10 vs. 2.55 kg/d).
Passage rate of particulates from the rumen was fastest for alfalfa and slowest for brome alone (Table 3). Passage of the mixed diet was intermediate to that of the individual forages. The Yb label was sprayed onto a portion of the forage diet, and unbound or loosely bound label was not removed before feeding. Thus, after consumption, much of the Yb could have migrated to binding sites in ruminal contents. This could have the greatest impact on passage rate for cattle fed the combination of alfalfa and brome because it is possible that the label was preferentially bound to particles from one of the forages. Regardless, the observed differences between alfalfa and brome in passage rate from the rumen would be important contributors to the differences in forage intake because, with faster passage and/or digestion, intake can be increased without subsequent increases in ruminal fill. Given the faster ruminal passage rate but higher digestibility of OM for alfalfa (61.0%) than brome (55.7%), one could conclude that the rate of ruminal digestion of alfalfa was greater than that of brome. Supplementation with CMB had no effect on passage rate, which is not surprising because neither intakes nor digestibilities were impacted.
Implications
When low-quality forages were fed to heifers, responses to supplementation with cooked molasses blocks were greater when the blocks contained a higher level of crude protein, suggesting that the primary response was to the supply of nitrogen. Responses to cooked molasses blocks were similar for cattle fed prairie hay only or prairie hay supplemented with alfalfa, suggesting that both of those forage diets were deficient in ruminally available nitrogen. Supplementation with a high-protein cooked molasses block had little effect on forage intake or digestion when alfalfa (19% crude protein), brome (8% crude protein), or a mixture of these two forages was fed to growing steers, suggesting that those forages were not deficient in ruminally available nitrogen and that, under those conditions, the cooked molasses block did not modify ruminal metabolism such that intake or digestion was altered. Cooked molasses blocks are a useful mechanism for supplying protein to forage-fed cattle.
Footnotes
1 Contribution 02-370-J, Kansas Agric. Exp. Stn., Manhattan. 
2 Correspondence—e-mail: etitgeme{at}oznet.ksu.edu.
Received for publication July 31, 2003. Accepted for publication October 20, 2003.
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