DECI s BULLETIN 405 OCTOBER 1970 Some Relationships between Chemical Composition and Nutritive Qualities of Coastal lBermudagjrass Hays for Dairyj Cows Aqriculturol AUB3URN Experiment Station UNIVERSITY Director ~'E V Sm ith Auburn, Alabama CONTENTS Page GENERAL EXPERIMENTAL PROCEDURES-3 Description of Hays .3--------Chemical Methodology---------------Digestihility Methodology-- -- ----- ---- -3 -4 -4 --- Milk Production Experiments ---Hay Intake Data -- ----- --- --- - -- --- ------ - -- 5 5 RESULTS AND DISCUSSION------------- Composition of Coastal Bermudagrass Hays-5 Digestihility of Coastal Bermudagrass Hays-7 Relationships hetween Chemical Composition and N utritive Q uality------------------------------- 8 Relationship of Hay Intakes to Chemical Composition------11 Milk Production Experiments -----------------------11 Milk Production and Hay Intakes and Composition Relationships ------------------------- 17 S UM M ARY -- - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - 18 R E FE RE NCE S - - - - - - - - - - - - - - - - -- - - --- - - - - - - - - - - - - - - - - - - -. 2 1 FIRST PRINTING 4M, OCTOBER 1970 Some Relationships between Chemical Composition and Nutritive Qualities of Coastal Bermudagrass Hays for Dairy Cows GEORGE E. HAWKINS and JOE A. LITTLE' ing program of Alabama dairymen. Nutritive quality of this grass hay varies widely from lot to lot. Thus, to effectively formulate a ration that will maintain milk production, dairymen need to know the nutritional qualities of each lot of Coastal bermudagrass hay. This requires that the relationship be known between total nutritive value and some easily measurable property of the hays. To meet this need a study was conducted to determine the variation in nutritive value of Coastal bermudagrass hay and to determine the value of certain chemical entities in characterizing total nutritive value of these hays. GENERAL EXPERIMENTAL PROCEDURES Description of Hays Fifteen lots of Coastal bermudagrass hay representing a wide range in inutritional qualities were used in a series of digestion trials and hay intake and milk production experiments. Hays 11 and 12 were first cuttings harvested June 3 and June 30, respectively. Hays 1 and 13 were second cuttings and hays 2 and 3 were third cuttings. The other lots were purchased on the open market without knowledge or regard to time of cutting. Chemical Methodology A core sample was taken from 20 or more bales of each of the 15 Coastal bermudagrass hays and composited for chemical analyses. The moisture, crude protein (CP), crude fiber (CF), ether extract (EE), nitrogen-free extract (NFE), ash, starch, calcium Professor and Instructor, Department of Animal and Dairy Sciences. COASTAL BERMUDAGRASS HAY is an important forage in the feed- 4 ALABAMA AGRICULTURAL EXPERIMENT STATION (Ca), manganese (Mn), sulfur (S), chlorine (Cl), and iodine (I) contents of the hays were determined by official methods (3). The method described by Crampton and Maynard (12) was used to determine cellulose, and lignin was determined by the sulfuric acid method (13). Sugars, phosphorous (P), and magnesium (Mg) were determined colorimetrically, sodium (Na) and potassium (K) by flame photometry, and copper (Cu), iron (FE), and zinc (Zn) by x-ray spectrography. Cold water extractables were determined by measuring the loss in dry matter after steeping 24 hours at room temperature. Hot water extractables were determined by refluxing a sample of the hay in distilled water for 1 hour, and measuring the loss in dry matter. The proximate composition (3) and lignin (13) of fecal matter were determined by the methods used for analyzing the hays. Volatile fatty acids (VFA) in rumen fluid were determined by gas chromatography. Fat content of milk was determined by the Babcock method and energy content of milk by oxygen bomb calorimetry. Digestibility Methodology Digestible dry matter (DDM) of hays 1 to 7 was determined initially by the chromogen method (28). This method gave low digestibility values. Therefore, DDM of hays 1 to 7 subsequently was determined by a combination of lignin ratio and total collection methods with four dairy animals per hay. The total collection method with three steers per hay was employed to determine digestibilities of hays 8 through 15. All total collections were made during 7-day periods following 7-day preliminary feeding periods. Total digestible nutrients (TDN) were determined in the usual manner, i.e., TDN - digestible protein + (digestible EE X 2.25) + digestible CF + digestible NFE. The ENE values of the hays were calculated from TDN contents as described by Moore, et al. (25). Milk Production Experiments Three continuous-design lactation experiments were carried out with the Coastal bermudagrass hays during different years to evaluate the relationships between indicators of hay quality and milk production. In Lactation Experiment I, hays 1 to 7 were the test forages; because of limited quantities of the hays, only two cows were fed each of these during a 38-day period. In Lactation Experiment II,-hays 8 to 10 were the test forages and each was fed COMPOSITION AND QUALITY OF COASTAL HAY 5 to five lactating cows during 42-day intervals. Hays 11 to 15 were the test forages for Lactation Experiment III and each was fed to five cows during a 35-day period. Feed allowances of the cows provided 110 per cent of Morrison's recommended TDN allowances in which half of the air-dry ration was hay and the other half was a concentrate mixture containing 16 per cent crude protein. The cows were individually fed twice daily and amounts fed and refused were recorded. The ratio of hay to concentrates consumed was variable because of some refusal of hays. During the experiments all cows were housed in individual stalls in a barn bedded with wood shavings. The cows were milked twice daily and the amount produced by each cow at each milking was recorded. Water was available at all times. Rumen fluid samples were collected approximately 2 hours after the morning feeding, from cows fed hays 8 through 15, to evaluate relationships among hay quality, rumen fluid VFA ratios, and milk production. To obtain an overall evaluation of feed energy utilization in the lactation experiments, the energy content of milk produced was determined and body weight changes were converted to energy equivalent by using the factor of 1,900 kcal. per pound of gain (14). Body weight changes were determined by differences in 3-day average weights taken at beginning and end of each experiment. Hay Intake Data Amounts of hays eaten daily by cows on the lactation experiments were used to evaluate relationships between intakes and chemical composition of the 15 Coastal bermudagrass hays. Additionally, the relationships between intake of hays 11 through 15 and chemical entities were evaluated by feeding the hays as the exclusive diet of steers. Each steer was fed each hay in one of the five 2-week experimental periods. To ensure that quantity of hay available would not limit intake, the steers were fed an excess of the hays. RESULTS AND DISCUSSION Composition of Coastal Bermudagrass Hays The proximate composition, cellulose, lignin, starch, cold and hot water solubles, and total sugar contents of the 15 Coastal 6 ALABAMA AGRICULTURAL EXPERIMENT STATION bermudagrass hays are presented in Table 1 and mineral compo- sition is recorded in Table 2. The 15 hays averaged 0.48 per cent calcium and 0.26 per cent phosphorus. This indicates that, when feeding Coastal bermudagrass hays as the only roughage, a supplement of calcium often will be needed for lactating cows and a supplement of phosphorous will be needed for normal growth of dairy heifers weighTABLE 1. PROXIMATE COMPOSITION, CELLULOSE, STARCH, LIGNIN, HOT WATER SOLUBLES, AND TOTAL SUGAR CONTENTS OF COLD AND 15 COASTAL BERMUDAGRASS HAYS, DRY-MATTER BASIS Hay No. Proximate composition Cellu- Starch Lig- CWS HWS Total CP CF Pet. Pet. 1------------------ 9.8 32.7 2-------------8.5 34.5 3_________________ 7.1 32.9 4___-____________ 12.1 36.9 5_ 14.7 34.2 6--------7_________ .13.4 EE Pet. 2.1 2.1 2.1 2.2 2.0 2.9 2.5 Ash Pet. 5.9 4.1 4.1 5.8 5.0 5.6 5.9 NFE Pet. 49.5 50.8 53.8 43.0 44.1 45.4 46.4 lose Pet. 31.7 31.9 31.4 30.7 31.2 31.2 31.4 Pct. rim Pet. 11.4 Pct. Pet. 18.6 sugar Pct. -9.9 3.0 1.8 __ 20.1 1.4 1.3 10.7 10.5 10.2 18.7 22.0 26.2 21.4 20.0 20.6 23.2 23.7 0.8 0.9 2.7 2.3 1.7 2.2 3.9 1.6 3.4 3.4 2.6 10.8 32.7 34.4 8_________ 6.7 30.9 31.9 32.0 28.5 32.0 31.4 31.6 32.6 2.0 2.0 2.0 2.8 2.1 2.3 2.0 1.7 3.8 4.2 3.7 6.2 5.9 5.3 5.4 5.3 56.6 55.8 55.4 48.5 48.2 50.5 51.4 53.4 30.9 31.0 31.8 27.8 30.3 30.6 31.3 32.4 -- 9.6 22.0 24.2 3.2 9.7 ---- 1.5 --2.2 10.5 3.1 2.2 1.7 1.0 1.1 1.9 2.2 10.7 11.~3 9.3 10.5 10.1 9.6 10.1 19.2 21.7 28.6 25.0 26.4 25.7 22.4 25.3 20.6 30.1 23.4 25.9 25.9 22.9 9--------- 6.1 10--------6.9 11--------- 14.0 12--------- 11.8 13--------- 10.5 9.6 15__------- 7.0 14--------- Mean______ TABLE 9.9 2. 32.6 2.2 5.1 50.2 31.0 15 2.0 10.3 23.1 23.4 2.2 MINERAL COMPOSITION OF THE HAYS, DRY-MATTER COASTAL BASIS BERMUDAGRASS Ca P Pet. Pet. 1--- 0.97 0.23 2 .52--- .17 .15 3--------- .62 .57 .27 4- --- ---.27 .34 5---------6- - --.33 .25 72--------9 .28 .22 .35 8---------.27 9---- ---- .42 10------ .36 .22 11------ - - .66 .41 12---- .58 .29 13------ .49 .30 14-------.43 .29 15--- .32 .22 Mean--. 48 .26 Hay No. Mg Pet. 0.14 Na Pet. _ K Pet. 0.73 .51 S Pet. Cl Pet. Mn Fe Zn I P.p.m. P.p.m. P.p.m.P.p.m. __ --_ 185 53 311 .08 0.04 0.25 __ .16 0.26 .16 -41 47 42 .09 .21 .19 .09 .22 .11 .11 .15 .16 .16 .17 .15 .10 .14 .08 .07 .06 .08 .02 .02 .04 .24 .09 .16 .16 .06 .09 2.22 1.32 1.26 .66 .67 .60 .69 1.52 1.46 .98 .95 1.40 1.07 .24 .16 .52 213 280 1.3 -- .26 .24 .24 118 120 41 .23 .15 .20 .09 .28 .27 .32 .21 .22 .22 .33 159 .34 111 .21 84 .26 84 .27 73 .65 64 .58 74 .45 31 .49 96 .46 95 .37 104 136 154 116 125 131 126 213 141 113 97 154 50 48 28 28 35 28 24 31 26 26 35 .7 1.0 4.1 1.1 1.3 1.4 .7 4.5 9.0 .6 2.3 COMPOSITION AND QUALITY OF COASTAL HAY 7 ing less than 400 pounds (11). The magnesium content was relatively low in hays, 2, 3, 6, 8, 9, and 15, yet each of these would have met the minimum requirement (0.07 per cent air-dry basis) of this element for growing heifers (7). As with most feed, average sodium content (0.09 per cent) of the hays was inadequate to meet the maintenance requirements of dairy cows (11) and, on the average, cows would need to eat 2 pounds of Coastal hay per 100 pounds of body weight to obtain adequate chlorine for maintenance (11). The amounts of manganese, iron, zinc, and iodine found in the hays, although variable, would be expected to meet the minimum requirements of cattle (30). Since the hay samples were ground through a brass screen prior to analysis, there was a chance for contamination with copper. For this reason the copper values are not reported. However, Anthony and Cunningham (1) found that Coastal bermudagrass from 67 Alabama counties averaged only 6 p.p.m. of copper and many Coastal samples from Alabama farms were deficient in both cobalt and copper (2). Digestibility of Coastal Bermudagrass Hays Digestibility data on the 15 Coastal bermudagrass hays fed in this series of digestion and lactation experiments are given in TABLE 3. SOME MEASURES OF THE NUTRITIVE VALUE OF 15 COASTAL BERMUDAGRASS HAYS, DRY-MATTER BASIS Hay No. . 1........... 2--------------3- - - 4 ----- ---------------. .. 5------6--------------7---------- --- --8 --------9--------------10--------------11 ............. ----12------13--------------14--------------------- ---15-Mean 1 DP Pct. 4.8 4.6 3.0 7.5 9.4 8.5 5.8 3.2 2.5 3.2 9.3 6.8 6.5 5.6 3.1 5.6 DDM Pct. 55.8 53.2 51.9 52.9 57.5 57.6 56.0 54.8 53.6 54.4 63.7 57.5 57.1 58.0 54.3 55.9 TDN Pct. 54.1 52.8 52.6 52.3 54.2 55.6 53.9 54.9 54.0 55.6 62.2 55.9 56.3 56.7 52.8 54.9 ETDN1 Pct. 54.7 DE Pct. 52.9 49.3 48.3 48.4 ENE 2 Mcal./100 lb. 40.7 38.9 38.6 38.2 40.9 42.8 40.5 41.8 40.6 42.8 52.0 43.2 43.8 44.4 38.9 41.9 52.5 53.7 51.2 54.8 55.9 53.4 55.9 53.7 52.4 52.7 55.6 54.4 54.6 50.8 53.1 60.5 56.1 56.4 55.9 53.9 54.9 58.8 55.5 53.8 55.5 51.8 52.9 Estimated TDN % -- [(3079 + % EDP X 14) - (% CF X 36.84)] 3563 X 100. Calculated by the equation, ENE (d ry-matter basis) = 1.393 (% TDN) 34.63, developed by Moore et al. (25). 8 ALABAMA AGRICULTURAL EXPERIMENT STATION Table 3. Apparent digestible protein (DP), DDM, TDN, estimated total digestible nutrients (ETDN), digestible energy (DE), and estimated net energy (ENE) values show that quality of the hays varied. These measures indicated that most of the hays were relatively low in quality and that hay 11, an early first cutting hay, was superior to all others. Relationships Between Chemical Composition and Nutritive Quality As shown by the correlations in Table 4, the DDM, TDN, DE, and ENE values for the Coastal hays increased as crude protein, total sugar, and cold and hot water extractables of the hays increased. The relatively high correlations between cold water extractables and both DDM and DE (r = 0.87) suggest this simple determination would be highly useful in evaluating nutritive quality of forages. The DDM, TDN, DE, and ENE values for the Coastal hays decreased as the crude fiber, cellulose, and lignin contents increased. For each per cent increase in crude fiber there was a decrease of 0.95 per cent in DDM, 1.02 per cent in TDN, 1.01 per cent in DE, and 1.425 megacalories of ENE per 100 pounds of the Coastal hays. As shown in Figure 1, digestible protein in the Coastal bermudagrass hays was linearly related to the crude protein content of the hays. From this relationship an equation was developed for determining estimated digestible protein (EDP) of Coastal hays from their crude protein contents (dry-matter basis), Figure 1. TABLE 4. CORRELATIONS BETWEEN SOME COMPONENTS OF THE 15 COASTAL BERMUDAGRASS HAYS AND CERTAIN MEASURES OF THEIR NUTRITIVE VALUE Component Crude protein Crude fiber Cellulose ---------Lignin DDM 0.681 Correlation coefficients TDN DE 0.44 - ENE 0.43 0.562 - - .631 .751 .711 .80' .82' .50' .661 .711 .592 - .80' .82' .532 Total sugar Cold water extractable Hot water extractable .78 .87 .84' - .751 .73' .83' 0.01. 0.05. .78 .871 .78 .761 .731 .84' 1 Correlation coefficients are significant, P 2 Correlation coefficients are significant, P COMPOSITION AND QUALITY OF COASTAL HAY 9 Digestible protein, per cent %EDP = (0.821 x %CP)-2.57 Crude protein, per cent FIG. 1. Digestible protein in Coastal bermudagrass hay was linearly related to the crude protein content. Estimated digestible protein (EDP) can be calculated CP X 0.821) - 2.57. by the equation, %EDP -(% The relationship between crude protein and digestible protein and between crude fiber and TDN in the 15 Coastal bermudagrass hays was used to develop an equation for estimating the TDN (ETDN) content. Using the equation from Figure 1 to determine EDP from CP the equation for % ETDN -= [3079 + (%EDP X 14) - (%CF X 36.84) ] X 100. 3563 The agreement between the ETDN and TDN values for the 15 hays was good, Figure 2. The maximum variation between these two values was 1.7 per cent (hay 11) and the standard deviation (S.D.) for the TDN-ETDN comparison for the 15 Coastal hays was 0.85 per cent. The foregoing equation gave a 10 ALABAMA AGRICULTURAL EXPERIMENT STATION TDN, per cent 63 62 61 60 59 58 57 56 55 54 "" 53 52 51 0 51 52 53 54 55 56 57 58 per cent 59 60 61 ETDN, FIG. 2. Estimated total digestible nutrients (ETDN) in relation to total digestible nutrients (TDN) in the 15 Coastal bermudagrass hays are shown. closer estimate of TDN values of these hays than was obtained by using a general equation (6), usually referred to as the Pennsylvania State prediction equation. The general equation, which has been widely employed in forage testing, overestimated TDN of the hays by an average of 2.6 per cent. The proportion of COMPOSITION AND QUALITY OF COASTAL HAY 11 chemically different compounds that make up the crude fiber fraction of different feeds (27) and of a single forage species at different stages of maturity (4) vary. Thus, it appears that the relationship between crude fiber and TDN in Coastal bermudagrass hays is more constant than that found across forage species and probably explains the increased accuracy obtained for ETDN by the equation developed from the 15 Coastal hays. Relationship of 'Hay Intakes to Chemical Composition The mean daily intake of hays 11 through 15 by dairy steers is given below: Hay No. 11 12 13 14 15 Daily hay intake per 100 lb. body weight, lb.1 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2.67a 2.30c 2.04c 2.22c 2.06c 1Values followed by unlike superscripts differ significantly. The steers received no other feed and consumed significantly more of hay 11 than of the other hays. Amounts consumed by steers were correlated significantly with the crude fiber (r -0.87), cellulose (r = -0.89), crude protein (r = 0.84), and ash (r = 0.95) contents of the hays. Intakes of the hays per 100 pounds of body weight decreased 0.14 and 0.13 pound for each per cent increase in crude fiber and cellulose, respectively. The contrasting increase in intake (per 100 pounds of weight) for each per cent increase in protein and ash were 0.08 and 0.56 pound, respectively. These data indicate that hay 11 (an early first cutting) was superior to hay 12 (a late first cutting) and to hay 13 (a second cutting representing 53 days of regrowth). This observation is similar to that reported by others (8,9,10,15,20,21,22, 23) that the nutritive value of Coastal bermudagrass hay decreased as the forage matured. Milk Production Experiments Composition of the concentrates, air-dry basis, fed in the three milk production experiments were as follows: Experiment I II III CP, pct. 15.9 16.4 17.0 CF, pct. 3.8 4.1 7.0 Ash, pct. 3.1 3.5 3.1 ENE, Mcal. 73.1 71.6 71.6 12 TABLE 5. 12 ALABAMA AGRICULTURAL EXPERIMENT STATION MEAN DAILY INTAKES OF TOTAL RATION IN WHICH EACH COASTAL BERMUDACRASS HAY WAS FED HayBody weight Hay Concentrates Intakes Total Lb. Experiment I 1,168 1--------------------------------------1,096 2 --------------------------------------1,132 3--------------------------------------4-------------------------------------959 1,2 18 5 --------------------------------------1,082 6--------------------------------------7--------------------------------------981 Experiment II 1,212 8-----------------------------------1,242 9-------------------------------------10------------ --------------------------- 1,266 Experiment I 1297 11-------------------------------------12 -------------------------------------1,163 13 -------------------------------------1,319 14 -------------------------------------1,305 15 _ --------- .___________________1,114 Lb. 16.5 14.2 16.4 13.7 19.6 16.3 14.1 16.8 17.0 15.9 19.5 15.9 17.3 18.2 15.4 Lb. 20.2 18.5 23.5 21.3 24.5 20.3 22 .4 21.8 24.4 22.8 20.6 19.5 21.8 21.4 20.4 Lb. 36.7 32.7 39.9 35.0 44.1 36.6 36.5 38.6 41.4 38.7 40.1 39.1 39.6 35.8 35.4 TABLE 6. RELATIONSHIP BETWEEN COASTAL BERMUDAGRASS HAY FED AND MEAN DAILY FCM PRODUCTION Hay No. No. No. ofMean Standardcows izafion' of ndrd daily FCM Experimental Experimental adjusted 2. 3 Lb. Experiment I 1----- ---------- ---------- -------------2 -- --------------------3-----------------------4-----------------------5-----------------------6 ----------------------2 2 2 2 2 2 2 5 5 5 5 5 5 5 5 32.5 33.2 37.9 38.2 38.3 38.0 39.2 44.8 45.3 44.2 41.8 39.5 41.4 42.6 40.0 Lb. 30.3 27.8 33.9 33.9 35.3 35.5 34.8 35.3 35.8 33.6 38.4 34.6 Lb. 35 .2 32.2d 35.2 35.0 36.3 36.7e 35.2 31.9 32.1 30.6 37.1 34.8 36.1 34.8 36.4 7-----------------------Experiment II 8-----------------------9-----------------------10-----------------------Experiment III 11-----------------------------12-----------------------13-----------------------14-----------------------15 ----------------------2 FCM 37.2 36.7 36.3 ' Mean daily FCM production was 39.8 pounds per cow. production adjusted to take into account the differences in average starting level. value followed by superscript d differed (P 0.05) from that followed by e. 'The < COMPOSITION AND QUALITY OF COASTAL HAY 13 Mean body weights of cows assigned to each hay, and the mean daily intakes of hay, concentrate, and total ration for the three milk production experiments are given in Table 5. Cows on each ration refused some of their hay allowance. For this reason, hay intake as a percentage of the total ration was variable. During Experiment I, the daily FCM production per cow fed hay 6 was greater than that of cows fed hay 2, Table 6. Within experiments the mean daily FCM production by cows fed the three hays in Experiment II and by those fed the five hays in Experiment III did not differ. Variations in FCM production among SMilk persistency, per cent FIG. 3. Mean persistency of actual milk production by cows fed Coastal bermudagrass hays 1 to 7 during Lactation Experiment I is illustrated here. 14 ALABAMA AGRICULTURAL EXPERIMENT STATION Milk persistency, per cent 100 90 9(:) o 80° 70 o3 2 3 4 Weeks of experiment 5 6 FIG. 4. Mean persistency of actual milk production by cows fed Coastal bermudagrass hays 8, 9, and 10 during Lactation Experiment !1 is illustrated here. individual cows on the same hays were large, thus masking any differences among the hays. Persistency of milk production is another measure of the nutritive adequacy of the rations containing Coastal hays. Persistencies of actual milk production each week as a percentage of that produced during the week preceding Experiments I, II, and III are shown in Figure 3, 4, and 5, respectively. In Experiment I cows fed hay 1 were the most persistent in production followed by those fed hays 6 and 5, with the lowest persistency occurring for cows fed hays 3 and 2, Figure 3. The rate of decline in milk production was unusually steep for cows fed all hays in Experiment II, Figure 4. In Experiment III, milk production of cows fed hays 11 and 15 persisted at higher levels than that of cows fed the other hays, Figure 5. Within experiments the milk energy produced by cows fed the Coastal hays did not differ significantly, Table 7. When ranked from highest to lowest, however, the milk energy produced by cows within experiments showed a close relationship to quality of the hay fed, with the highest quality hays supporting the high- COMPOSITION AND QUALITY OF COASTAL HAY 15 IMilk cent per 95 persistency, N. 80 0 FIG. 5. I 2 Weeks 3 4 of experiment 5 Mean persistency of actual milk production during Lactation Experiment Ill is illustrated here. est performance. In all experiments the cows gained some weight, Table 7. The mean molar percentages of volatile fatty acids in rumen fluid from the cows varied among hays, Table 8, and within hay groups. As the percentage of concentrates in the total feed intake increased, molar percentages of acetic and butyric acids decreased and that of propionic acid increased. The molar per cent of propionic acid in the rumen fluid of some cows increased and in other cows decreased from the standardi- 16 16 ALABAMA AGRICULTURAL EXPERIMENT STATION TABLE 7. MEAN DAILY MILK ENERGY PRODUCED AND MEAN DAILY WEIGHT CHANGE BY Cows FED THE COASTAL BERMUDAGRASS HAY RATIONS BODY Hay No.weight Experiment I 1--------------------- Milk energy Actual Meal. 9.844 Adjusted 1 '2 change Lb. 2.29 Body Meal. 11.178 10.371 2------ --------------------------------3--------------------------------------4--------------------------------------5--------------------- 9.203 11.018 11.070 11.608 10.559 10.761 11.316 1.25 0.84 1.09 3.45 6 - ------ ------ ------------------------------------------- 11.65 9 7--------------------------------------Experiment IL 8--------------------------------------- 11.840 11.761 11.216 10.838 11.577 1.82 1.09 0.16 9--------------------------------------10 ----------------------------------- 11.815 10.913 11.700 11.213 12.778 12.564 12.463 0.36 0.49 0.98 0.18 0.31 Experiment III 11------- -----------------12 ---------------- - --------------------13----------------.--------------------14------------------------------- --- 15 ---------------------------------------- 12.808 12.120 12.696 12.249 12.699 11.722 13.048 0.98 0.94 'Adjusted by covariance within experiment to take into account the initial differences in levels of milk energy secreted by individual cows during the standardization period. 2 Difference required for significance in Experiment I, II, and III is 1.265, 1.491, 1.475 Mcal., respectively. TABLE 8. MEN MOLAR PERCENTAGES OF VOLATILE FATTY ACIDs IN RUMEN LIQUOR FROM FED COASTAL BERMUDAGRASS HAYS Cows HyN.Feed intake as concenratesAcetic VFA in rumen liquor Propionic Butyric Isovaleric Valeric Pct. Experiment II 8 56.5-------------9 58.9-------------10 58.9----------- --Experiment III 11 12 51.4-------------- Pct. 64.0 67.2 65.7 71.0 63.9 Pct. 22.7 20.2 19.7 15.6 21.22 Pct. 13.3' 12.6' 14.6 11.4 11.9 Pet. --- Pet. ----- -1.1 1.9 13 14 15 55.1 -------------55.8 -------------54.0------------57.0 0.9 1.1 68.3 68.8 67.1 16.9' 17.3 18.3 12.1 11.7 12.2 1.3 1.1 1.1 1.3 1.0 1.3 -------------- 1Includes isovaleric and valeric acids. Molar per cent of propionic acid differed significantly after correction for per cent concentrate in the ration consumed. 2 COMPOSITION AND QUALITY OF COASTAL HAY 17 zation period to end of the experimental period. Within Experiment III, the change in molar per cent of propionic acid during significantly the experimental period was correlated (r =-0.66) with the change in fat percentage of milk produced by individual cows. Milk Production and Hay Intakes and Composition Relationships For all hays in the experiments there was a high degree of variability in milk production responses of cows fed the same hays. The results are similar to earlier findings when Coastal was fed (16). Consequently for hays 1 to 7, each of which were fed to only two cows, variability was so great that the average response may not be indicative of hay quality. Nevertheless, it was found that across all 15 Coastal hays, the mean daily FCM and milk energy persistency increased significantly as hay intake per 100 pounds of body weight increased, r - 0.63 and 0.51, respectively. Increase in lignin content of the hays was significantly nega-0.67). On the tively correlated with FCM persistency (r average, FCM persistency decreased 5.92 per cent for each per cent increase in lignin content of the hays. This was associated with a decrease in hay intake equal to 0.08 pound daily for 100 pounds of cow weight for each per cent increase in lignin content. Hays 8 to 15 were each fed to five lactating cows, whereas hays 1 to 7 were each fed to only two cows. For this reason correlations were determined between some measures of quality for only hays 8 to 15 and the mean FCM persistency of cows to which they were fed. The cold water solubles per cent of the hays and FCM persistency were correlated (r = 0.83) significantly. Average persistency of FCM over the 5-week period increased 1.49 per cent for each percentage increase in cold water solubles in the hays. Although crude fiber contents of the 15 hays were not correlated significantly with FCM persistency (r - -0.31) of cows to which the hays were fed, the relationship was negative. On the average, FCM persistency decreased 1.4 per cent for each per cent increase in crude fiber. In a like manner, the persistency of FCM production by cows fed rations containing the 15 hays was not correlated significantly with crude fiber contents of the complete rations, which ranged from 14.2 per cent for the hay 9 ration to 16.8 for rations which included hays 12 and 14. The absence of a trend in FCM production in relation to total ration 18 ALABAMA AGRICULTURAL EXPERIMENT STATION crude fiber percentage over the range of 14 to 17 per cent agrees with reports of others (24,29). Nevertheless, there is some evidence (26) that 16 per cent crude fiber in the ration approaches the optimum level. Autrey (5) found that cows could consume approximately 0.6 pound of crude fiber per 100 pounds of body weight. However, it would appear that other factors limited the total feed intake of the Coastal bermudagrass hay rations before crude fiber level of the ration became a limiting factor. Crude fiber intakes ranged from 0.44 to 0.57 pound per 100 pounds of body weight. Intake of DP by cows fed the rations containing the 15 Coastal bermudagrass hays exceeded the recommended allowances (11). The utilization of ENE intakes for maintenance and milk production by cows fed rations including hays 11 to 15 was 97.3 to 101.9 per cent. In contrast, cows fed hays 1 to 10 used only 84.8 to 93.1 per cent of their ENE intake for body maintenance and milk energy production with most of the remainder being accounted for as stored body tissue. SUMMARY The quality of the 15 Coastal bermudagrass hays fed in the digestibility and lactation studies reported herein was highly variable as measured by chemical composition, by digestibility of protein and of energy, and by animal performance. Apparent digestible protein contents of the 15 Coastal bermudagrass hays was linearly related to level of crude protein in the hays and could be estimated with a high degree of precision by the equation, % EDP = (% CP X 0.821) - 2.57. The TDN content of the 15 hays decreased 1.02 per cent for each per cent increase in crude fiber over the range found in these hays (28.5 to 36.9 per cent). The correlation (r -= -0.80) between crude fiber and TDN was highly significant. The relationships between crude protein and digestible protein and between crude fiber and TDN were used to modify a prediction equation (6) for obtaining greater accuracy in estimating the TDN of Coastal bermudagrass hays. The modified prediction equation for estimated TDN of Coastal bermudagrass hays is [3079 + (%EDP X 14) - (%CF X 36.84) ] % ETDN X 100. 3563 COMPOSITION AND QUALITY OF COASTAL HAY 19 This equation is being used in the Alabama forage testing program to estimate TDN of Coastal bermudagrass hays. The Ca, P, Mg, and Na contents of several of the hays were either too low to meet minimum requirements for growth or for lactation unless fed with a concentrate containing a supplement of these minerals. Also, copper and cobalt contents of Coastal hays often are below levels required by cattle (2). The highest quality Coastal bermudagrass hay was an acceptable forage as measured by ENE, by the amount consumed per cow daily, and by milk production persistency. COMPOSITION AND QUALITY OF COASTAL HAY 21 REFERENCES J. P. CUNNINGHAM, JR. 1969. Elements in CoasJ. Anim. Sci. 28:143. (2) AND R. R. HARRIS. 1965. Alabama Forages and Mineral Needs of Cattle. Highlights of Agr. Res. Vol. 12, No. 4. Auburn Univ. (Ala.) Agr. Exp. Sta. (3) ARMSTRONG, D. C., H. COOK, AND B. THOMAS. 1950. The Lignin and Cellulose Contents of Certain Grassland Species of Different Stages of Growth. J. Agr. Sci. 40:93. (4) ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS. 1960. Official Methods of Analysis. 9th ed. Assoc. Off. Agr. Chem. Washington, D.C. (5) AUTREY, K. M. 1941. The Physiologic and Economic Efficiencies of Rations Containing Different Amounts of Grain when Fed to Dairy Cattle. Ph.D. Thesis, Iowa State University, Ames. (1) ANTHONY, W. B. AND tal-Variations. (6) BAYLOR, J. E., R. S. ADAMS, AND J. W. BRATZLER. 1960. The Penn- sylvania System of Forage Evaluation. Paper presented to Am. Soc. Agr. Eng. and Am. Grassland Council, Ohio State Univ., Columbus, June 12-15. (7) BLAXTER, K. L. AND ROSEMARY F. MCGILL. 1956. Magnesium Me1968. tabolism in Cattle. Vet. Rev. Annot. 2:35. AND C. M. CLIFTON. (8) BROOKS, O. L., W. J. MILLER, E. R. BEATY, Pelleted Coastal Bermudagrass-Comprehensive Investigations. Ga. Agr. Exp. Sta. Res. Bull. 27. (9) BURTON, G. W., J. E. JACKSON, AND R. H. HART. 1962. Effect of Clipping Frequency on the Yield, Chemical Composition and In Vitro Digestibility of Coastal Bermuda Grass. J. Anim. Sci. 21:389. (10) CLIFTON, C. M., W. J. MILLER, AND N. W. CAMERON. 1963. Coastal Bermudagrass Hay and Silage at Two Stages of Maturity Fed with Two Concentrate Levels to Lactating Cows. J. Dairy Sci. 46:959. (11) (12) COMMITTEE ON ANIMAL NUTRITION. 1962. Nutrient Requirements of Dairy Cattle. Nat. Acad. Sci., Nat. Res. Council Pub. 464. 1938. The Relation of Cellulose and Lignin Content to the Nutritive Value of Animal Feed. J. Nutr. 15:383. (13) ELLIS, G. H., G. MATRONE, AND L. A. MAYNARD. 1946. A 72% H 2 SO4 Method for the Determination of Lignin and Its Use in Animal Nutrition Studies. J. Anim. Sci. 5:285. (14) GARRETT, W. N., J. H. MEYER, AND G. P. LOFGREEN. 1959. The Comparative Energy Requirements of Sheep and Cattle for Main. tenance and Gain. J. Anim. Sci. 18:528. CRAMPTON, E. W. AND L. A. MAYNARD. (15) HARRIS, R. R., W. B. ANTHONY, AND V. L. BROWN. 1962. Effect of Maturity and Method of Curing on Nutritive Value of Coastal Bermuda Grass Hay. J. Anim. Sci. 21:1035. (16) HAWKINS, G. E. 1958. Coastal Bermudagrass vs. Alfalfa Hay as a Dairy Feed. Highlights of Agr. Res. Vol. 5, No. 4. Auburn Univ. (Ala.) Agr. Exp. Sta. 22 ALABAMA AGRICULTURAL EXPERIMENT STATION (17) ----, G. E. PAAR, AND J. A. LITTLE. 1964. Composition, Intake, and Digestibility of Coastal Bermudagrass Hays. J. Dairy Sci. 47:865. 1964. Top Coastal Maintains (18) -----------------------------. Milk Production. Highlights of Agr. Res. Vol. 11, No. 4. Auburn Univ. (Ala.) Agr. Exp. Sta. 1964. Variation in Nutritive (19) ------------------------. Quality of Coastal Bermudagrass Hays. J. Dairy Sci. 47:342. (20) JOHNSON, J. C., JR., D. W. BEARDSLEY, G. W. BURTON, F. E. KNOX, AND B. L. SOUTHWELL. 1968. Effect of Age at Cutting and Weathering on Coastal Bermudagrass Hay. J. Dairy Sci. 46:365. (21) KING, W. A., C. C. BRANNON, AND J. T. GILLINGHAM. 1969. LowMoisture Coastal Bermudagrass Silage for Milking Cows. S.C. Agr. Exp. Sta. Dairy Res. Series No. 9. (22) KNOX, F. E., G. W. BURTON, AND D. M. BAIRD. 1958. Effect of Nitrogen Rate and Clipping Frequency Upon Lignin Content and Digestibility of Coastal Bermuda Grass. J. Agr. Food Chem. 6:217. (23) LEE, D. D., JR., W. CHALUPA, AND W. A. KING. 1964. Nutritive Value of Coastal Bermuda Grass Determined In Vitro. J. Anim. Sci. 23:899. (24) LITTLE, (25) (26) (27) (28) Fiber on Performance of Lactating Dairy Cows. J. Dairy Sci. 52:558. MOORE, L. A., H. M. IRVIN, AND J. C. SHAW. 1953. Relationship Between TDN and Energy Value of Feeds. J. Dairy Sci. 36:98. NORFELDT, S., I. IWANAGA, K. MORITA, L. A. HENKE, AND A. K. S. J. A. AND G. E. HAWKINS. 1969. Influence of Level of Crude TOM. 1950. Influence of Crude Fiber in the Ration on Efficiency of Feed Utilization by Dairy Cattle. J. Dairy Sci. 3388:473. , 0. SVANBERG, AND O. CLAESON. 1949. Studies Re- garding the Analysis of Crude Fiber. Acta Agr. Suecana 3:135. REID, T., P. WOOLFOLK, C. R. RICHARDS, LOOSLI, K. L. TURK, J. E. MILLER, AND R. E. J. J. . W. KAUFMANN, BLASER. J. K. 1950. A New Indicator Method for the Determination of Digestibility and Consump- tion of Forages by Ruminants. J. Dairy Sci. 33:60. SPAHR, S. L., A. E. BRANDING, E. M. KESLER, AND W. H. CLONINGER. 1966. Short-Term Effects of Dietary Fiber Level on Feed Intake and Production by Well-Fed Cows. J. Dairy Sci. 49:1046. (30) UNDERWOOD, E. J. 1962. Trace Elements in Human and Animal Nutrition. 2nd ed. Academic Press, Inc. New York, N.Y. (29) AGRICULTURAL EXPERIMENT STATION SYSTEM OF ALABAMA'S LAND-GRANT UNIVERSITY \itlh an agricultural csear ch unit in every m ajor soil area, Auburn nv e es te Unix isitv se~ves tiei. needs of field crop, livestock, forestry, and hortictiltural producers in each region ini Alab~ama. Everv citizen of the State has a stake in ® 1 13 ® 02 to n a this research program, since any advantage fror newv and more economical xvavs of ioducing and handling farm l)rolucts directly benefits tlh c nsulming Research Unit Identification 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. Tennessee Valley Substation, Belle Mina. Sand Mountain Substation, Crossville. North Alabama Horticulture Substation, Cullman. Upper Coastal Plain Substation, Winfield. Forestry Unir, Fayette County. Thorsby Foundation Seed Stocks Farm, Thorsby. Chilton Area Horticulture Substation, Clanton. Forestry Unit, Coosa County. Piedmont Substation, Camp Hill. Plant Breeding Unit, Tallassee. Forestry Unit, Autauga County. Prattville Experiment Field, Prattville. Black Belt Substation, Marion Junction. Tuskegee Experiment Field, Tuskegee. Lower Coastal Plain Substation, Camden. Forestry Unit, Barbour County. Monroeville Experiment Field, Monroeville. Wiregrass Substation, Headland. Brewton Experiment Field, Brewton. Ornamental Horticulture Field Station, Spring Hill. Gulf Coast Substation, Fairhope.