Effect of Yeast Culture (Saccharomyces cerevisiae) on Adaptation of Cows to Diets Postpartum1

NUTRITION, FEEDING, AND CALVES Effect of Yeast Culture (Saccharomyces cerevisiae) on Adaptation of Cows to Diets Postpartum1 P. H. ROBINSON The Atlantic Dairy and Forage Institute, 115 Sunburg Drive, Fredericton Junction, NB, Canada E0G 1T0

ABSTRACT For approximately 14 d prepartum and exactly 14 d postpartum, 20 multiparous Holstein cows were fed different basal diets that were supplemented, or not supplemented, with a yeast culture preparation. Cows supplemented with yeast culture lost less body condition prepartum, which was consistent with numerically higher body weight gain. No treatment differences were found in prepartum or postpartum dry matter intakes (DMI) or components of DMI. In addition, the extent of the depression in DMI prepartum and the rate of increase in DMI postpartum were not influenced by yeast culture supplementation. Milk and milk component yields were not influenced by yeast culture supplementation. Cows in both groups had higher calculated net energy for lactation for the diets postpartum than would have been expected based on values of the National Research Council for feedstuffs. The increased net energy for lactation seemed to be related to higher than expected metabolic efficiency during early lactation. Results of both the prepartum and postpartum periods were consistent with the hypothesis that supplementation of yeast culture in the diet increased net digestion in the forestomach, particularly of fiber, leading to increased energy output. However, there was no evidence to suggest that supplementation of yeast culture prepartum alleviated the reduction in DMI prepartum or improved the rate of increase in DMI postpartum. ( Key words: yeast culture, dairy cows, parturition)

ing and the 4th wk postpartum. To facilitate this increase, cows must remain on feed immediately prior to and during calving. However, Bertics et al. ( 1 ) and Van Saun et al. ( 1 1 ) have demonstrated depression in DMI of approximately 40% beginning at 7 to 10 d prepartum, which would be expected to make cows more susceptible to metabolic diseases that are associated with calving, such as ketosis and milk fever, and to make adaptation to the postpartum diet slower. Yeast products have been shown to modify rumen fermentation (7, 12), to stimulate the number ( 1 2 ) and growth (4, 6 ) of rumen bacteria, and to increase the initial rate of forage digestion in the rumen ( 2 ) . If DMI is reduced prior to calving and if this reduction is precipitated or exacerbated by an imbalance in rumen fermentation, yeast or yeast culture supplementation to the diet may prevent the reduction by stimulating microbial growth. However, if the prepartum reduction in DMI is caused by a change in intermediary metabolism, perhaps leading to a reduced ability to metabolize absorbed nutrients, then dietary addition of yeast or yeast culture may have little effect. The objective of this study was to examine the impact of a yeast culture supplement to the diet for 14 d prepartum and 14 d postpartum on DMI of dairy cows immediately before, during, and after parturition. In addition, the influence of a yeast culture supplement on performance of cows in the immediate postpartum period was determined.

Abbreviation key: BCS = body condition score, MD = mixed diet.

Cows and Diets

INTRODUCTION Dairy cows with the potential for high milk yield can increase DMI by as much as 150% between calv-

Received December 18, 1995. Accepted October 11, 1996. 1Research completed at the Agriculture and Agri-Food Canada Research Centre, Fredericton, NB, Canada. 1997 J Dairy Sci 80:1119–1125

MATERIALS AND METHODS

Forty pregnant multiparous Holstein cows were utilized. Cows were tethered in tie stalls and had free access to water. Each cow began the experiment at 21 d prior to the expected calving date. At that time, cows were fed 2.5 kg/d of one of two concentrates based on grain (Table 1 ) i n five equal meals/d at 1730, 2130, 0200, 0700, and 1130 h; up to 9 kg/d of a poor quality timothy hay at 1500 h (Table 2); 1 kg of

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ROBINSON TABLE 1. Ingredient and chemical composition of the concentrates. Prepartum Composition

Control

Yeast culture

Postpartum

(kg/tonne, as mixed) Ingredient Barley, ground Corn, ground Blood meal1 Soybean meal (48% CP) 2 Corn gluten meal Monoammonium phosphate Dicalcium phosphate Dynamate3 Limestone Trace-mineralized salt4 Iodized salt5 Se-Mar 2006 Vitamin A, D, and E premix7 Vitamin A premix8 Vitamin D premix9 Magnesium oxide Copper sulfate Yeast culture supplement10 Liquid molasses

845 0 15 80 20 2 0 0 0 5 0 0 3 0 0 0 0 0 30

Nutrient DM, 105°C

878.4

822 0 15 80 20 2 0 0 0 5 0 0 3 0 0 0 0 22.8 30

470 272 0 135 46 0 7.5 3.8 18.8 4.5 6 3 0 0.45 1.26 1.5 0.038 0 30

877.3

863.6

( % of DM11) OM NDF ADF Fat NEL,12 Mcal/kg CP Total Buffer insoluble Neutral detergent insoluble Acid detergent insoluble Ca P K Mg S Na

97.51 22.5 6.1 2.11 1.92

97.46 22.5 5.9 2.23 1.87

93.22 17.7 4.7 2.25 1.86

14.86 11.83 0.56 0.34 0.07 0.40 0.61 0.17 0.15 0.09

15.18 11.84 0.53 0.41 0.09 0.40 0.63 0.17 0.16 0.09

21.91 16.37 0.76 0.31 0.72 0.60 0.93 0.28 0.31 0.46

(ppm of DM) Zn Fe Mn Cu Se 1Ring-dried

50 117 31.9 6.60 0.071

50 158 33.5 6.85 0.043

53 167 47.0 13.61 0.757

(Llomex, Montreal, QC, Canada).

2Solvent-extracted. 3Dynamate (Pitman Moore, Inc., Oakville, ON, Canada) contained a guaranteed analysis of 22% S, 18% K, and 11% Mg. 4Guaranteed analysis: 37.6% Na, 37.5 of ppm Co, 75 ppm of I, 1875 ppm of Fe, 3000 ppm of Mn, 5625 ppm of Zn, 400 ppm of Cu, and 10 ppm of Se. 5Guaranteed analysis: 96.5% NaCl, 4000 ppm of Zn, 160 ppm of Fe, 1200 ppm of Mn, 330 ppm of Cu, 70 ppm of I, and 40 ppm of Co. 6Se-Mar 200 (Central Soya Ltd., Woodstock, ON, Canada) contained a guaranteed level of 200 ppm of Se and 11,000 IU/kg of vitamin E. 7Guaranteed analysis: 10,000,000 IU/kg of vitamin A, 1,000,000 IU/kg of vitamin D, and 75,000 IU/ kg of vitamin E. 8Guaranteed analysis: 12,500,000 IU/kg of vitamin A. 9Guaranteed analysis: 1,000,000 IU/kg of vitamin D. 10XP Yeast culture preparation of Saccharomyces cerevisiae (Diamond V Mills, Inc., Cedar Rapids, IA). 11Except NE . L 12Estimated from NRC ( 8 ) ; no NE was assigned to the yeast culture supplement. L

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DM/d of corn silage at 1630 h (Table 2); and 1 kg of DM/d of good quality timothy silage at 0600 h (Table 2). Orts were removed and weighed between 1300 and 1330 h daily, and all cows received between 60 and 90 min/d of exercise in a drylot beginning at 0730 h. At calving, all cows were changed abruptly to a mixed diet ( MD) of corn silage (22% of DM; Table 2), timothy silage (31% of DM; Table 2), and a concentrate based on grain (47% of DM; Tables 1 and 2). This MD was fed for ad libitum intake; two-thirds was fed at 1630 h, and one-third was fed at 0600 h. In addition to the MD, 1 kg of soybean meal was fed daily in two equal meals at 1730 and 0700 h. Housing, exercise, water, and the removal of orts were all completed as described for the prepartum period. Figure 1. Body weight by week relative to parturition for the cows in the control ( ♦) and yeast culture ( ◊) groups (SEM = 3 kg).

Experimental Design

TABLE 2. Chemical composition of the feedstuffs and the postpartum mixed diet. Feedstuff Corn silage DM, % 105°C Toluene OM NDF ADF NEL,3 Mcal/kg of DM CP Total NH3 N4 Buffer insoluble Neutral detergent insoluble Acid detergent insoluble Ca P K Mg S Na Zn Fe Mn Cu 1Not

30.85 32.32

Timothy Timothy silage hay

Mixed diet

33.64 92.02 35.28 ND1 ( % of 105°C DM2) 91.22 95.21 58.6 70.9 35.6 38.9 1.20 0.90

45.93 47.39

8.39 0.70 3.17

12.82 0.94 5.31

5.72 ND 6.72

14.25 0.49 9.42

0.74

2.95

3.10

1.59

95.70 46.9 26.0 1.65

0.23 0.19 0.28 1.02 0.17 0.11 <0.01 29 595 28.8 6.36

0.63 0.41 0.57 0.18 0.32 0.19 3.12 1.80 0.18 0.10 0.16 0.09 <0.01 <0.01 (ppm of DM) 21 11 335 64 31.3 76.9 4.32 3.85

92.96 32.5 19.3 1.61

0.48 0.72 0.43 1.64 0.24 0.21 0.27 41 426 40.2 11.78

determined. NEL. 3Estimated from the composition of the ingredients and reference to NRC ( 8 ) . 4CP Equivalent. 2Except

Cows were blocked into pairs based on lactation number, BW, and body condition score ( BCS) at assignment on d 21 prepartum. Two treatment groups were established. The control group received the control concentrate (Table 1 ) during the prepartum period and received the MD specified previously for 28 d postpartum. The yeast culture group received the control concentrate for the first 7 d of the prepartum period followed by the yeast culture concentrate (Table 1 ) until calving. The yeast culture concentrate supplied 57 g/d of a yeast culture product XP yeast culture preparation from Saccharomyces cerevisiae; (Diamond V Mills Inc., Cedar Rapids, IA) prepartum. For the postpartum period, 57 g/d of the same yeast preparation were manually mixed into the MD that was fed at 1630 h for 14 d. All cows completed the experiment on d 28 postpartum. Sampling Hay, silages, and the MD were sampled on d 1, 3, and 6 of each week and composited by week. Batch lots of ingredients used in the mixed concentrates were sampled twice during the experiment and composited. Each batch of mixed concentrate was sampled individually and pooled to create one composite sample for each of the three mixed concentrates. Orts were sampled on d 7 of each week and composited by cow to create a single prepartum composite sample of orts and a single postpartum composite sample of orts. Cows were milked twice daily at 0600 and 1530 Journal of Dairy Science Vol. 80, No. 6, 1997

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h. Milk samples for compositional analyses were collected on d 4 (p.m.) and 5 (a.m.) of each week. All cows were weighed and assessed for BCS weekly by two scorers according to the method of Edmonson et al. ( 5 ) . Statistical Analysis Milk yield, feed intake, BW, BCS, and energy balance were analyzed separately for the prepartum and postpartum periods using repeated measures procedures; treatment, cow within treatment, time (day or week as appropriate), and time by treatment interaction were factors. Significance was determined using cow within treatment as the error term. Differences between treatments were declared at P < 0.05. Analytical Procedures and Calculations

Figure 2. Body condition score (BCS; five-point scale where 1 = thin to 5 = fat) by week relative to parturition for cows in the control ( ♦) and yeast culture ( ◊) groups (SEM = 0.01 units).

All analytical procedures were completed as described by Robinson and McQueen ( 9 ) . The DMI and intake of components of the DM were calculated

TABLE 3. Prepartum1 intake, BW, and body condition score (BCS) as influenced by yeast culture supplementation. Treatment Control

Yeast culture

Contrast2 Treatment

Treatment × time

SEM

P Intake DM kg/d % of BW OM kg/d % of DMI NDF kg/d % of DMI % of BW CP kg/d % of DMI BW Mean, kg Change, kg/d BCS3 Mean, units Change, units/wk

10.97 10.79 1.52 1.48

0.65 0.50

0.10 0.08

0.14 0.02

10.46 10.28 95.36 95.32

0.64 0.31

0.16 <0.01

0.13 0.03

7.32 7.11 66.6 66.0 1.01 0.98

0.47 0.11 0.35

0.95 <0.01 0.96

0.10 0.4 0.01

0.93 8.68

0.62 0.11

<0.01 <0.01

0.02 0.11

724 730 0.19 0.36

0.79 0.46

0.76 0.66

3 0.11

3.49 3.50 –0.08 –0.01

0.93 <0.01

<0.01 0.23

0.01 0.02

0.92 8.46

1Includes

the day of calving. was significant ( P < 0.05) for all parameters except BW, BW change, and BCS change. Time is expressed as day prepartum for all intake parameters and week prepartum for all body parameters. 3Scored on a five-point scale where 1 = thin to 5 = fat ( 5 ) . 2Time

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on a weekly basis from the actual amount and composition of the feedstuffs offered. The composition of orts was assumed to be that of the sample composite of orts obtained within either the prepartum or postpartum periods as appropriate. Energy balance of the cows was determined individually by cow. Milk energy was calculated as suggested by Tyrrell and Reid ( 1 0 ) using milk fat, protein, and lactose. Energy for change in body condition was 250 Mcal/unit change in BCS ( 3 ) , and maintenance energy was (BW 0.75) × 0.08 ( 8 ) . RESULTS Cow Assignment Cows entered the experiment at an estimated 21 d prepartum and were assigned to diets at an estimated 14 d prepartum. Cows had to have calved no earlier than 8 d subsequent to dietary assignment to be included in the experiment. On this basis, 6 cows were eliminated. Furthermore, 7 cows were removed from the experiment because of health problems that were not considered to be associated with the treatments. The health problems were uterine infection at calving ( 2 cows), blind quarter ( 2 cows), teat injury from cow stepping on teat ( 1 cow), diagnosed hardware disease ( 1 cow), and inflamed hock caused by physical injury ( 1 cow). Thus, a total of 27 cows (13 from the control group and 14 from the yeast culture group) were included in the experiment. Cows were assigned to their prepartum diets for a mean of 16.6 ± 8.5 d. All reported data are from these 27 cows.

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more BW and lost less body condition ( P < 0.01) than did those fed unsupplemented diets. Some intake parameters indicated a significant ( P < 0.05) treatment by time interaction, which seemed to be related to the lower DMI of cows fed diets supplemented with yeast culture relative to control cows earlier in the 21-d prepartum period (Figure 3). Postpartum Performance

Figure 3. Dry matter intake by day relative to parturition for cows in the control ( ♦) and yeast culture ( ◊) groups (SEM = 0.23 kg/d).

Feedstuff Composition The two prepartum concentrates were very similar analytically (Table 1), except that the yeast culture concentrate had a slightly higher CP concentration. The corn silage was composed of fully developed ears, which was reflected by the relatively low fiber and CP concentrations (Table 2). Soluble CP and acid detergent insoluble CP, at 62.2 and 2.7% of CP, respectively, were normal for corn silage. Timothy silage was judged to be of moderate quality based on its fiber and CP concentrations. Concentrations of soluble CP and acid detergent insoluble CP were typical of this type of material. The timothy hay was poor quality based on its high fiber and low CP. Mineral concentrations in all forages were typical of the respective materials. The postpartum MD was characterized by moderate fiber concentrations and low CP with adequate concentrations of soluble CP and minerals. Prepartum Performance Intake of DM, OM, and their components was not influenced by yeast culture supplementation prepartum (Table 3). The CP concentration of the diet was low relative to NRC ( 8 ) values, which suggested a requirement of approximately 1.2 kg/d of CP for a 750-kg dairy cow in the last 2 mo of pregnancy. All cows gained BW, probably because of fetal development, but lost BCS (Figures 1 and 2). Cows fed diets supplemented with yeast culture gained numerically

Cows rapidly increased DMI postpartum to attain a DMI in excess of 20 kg/d by 28 d postpartum (Table 4). There was no difference between treatments, although cows receiving the yeast culture supplement tended ( P = 0.18) to consume a diet that was lower in NDF. The dietary CP concentration was higher than that in the MD because of supplementation with 1 kg/d of soybean meal. Cows were in negative energy balance as evaluated by change in BW or BCS. Milk yield increased rapidly over the first 4 wk postpartum to approximately 38 kg/d per cow (Figure 4). Milk and milk component yields were not in-

TABLE 4. Postpartum intake, BW, and body condition score (BCS) as influenced by yeast culture supplementation prepartum and postpartum. Treatment Control

Yeast culture

Contrast1 Treatment × time

SEM

0.82 0.73

0.42 0.40

0.23 0.04

0.82 0.95

0.43 0.99

0.21 0.05

0.98 0.35 0.99

0.20 0.33 0.20

0.08 0.4 0.01

0.70 0.54

0.77 0.99

0.04 0.15

0.95 0.34

0.90 0.84

3 0.13

0.54 0.44

0.69 0.87

0.02 0.03

Treatment P

Intake DM kg/d 17.38 17.62 % of BW 2.73 2.78 OM kg/d 16.15 16.38 % of DMI 92.92 92.96 NDF kg/d 5.80 5.77 % of DMI 33.6 32.9 % of BW 0.91 0.91 CP kg/d 2.81 2.88 % of DMI 16.28 16.51 BW Mean, kg 637 636 Change, kg/d –0.29 –0.14 BCS2 Mean, units 3.12 3.19 Change, units/wk –0.08 –0.06

1Time was significant ( P < 0.05) for all parameters except OM (percentage of DMI), BW change, and BCS change. Time is expressed as day postpartum for all intake parameters and week postpartum for all body parameters. 2Scored on a five-point scale where 1 = thin to 5 = fat ( 5 ) .

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fluenced by treatment (Table 5); concentrations of fat, protein, and lactose in milk similarly were unaffected. Calculated total energy output (Table 6), as well as energy in milk, body change, and energy for maintenance did not differ by treatment. However, the calculated dietary energy density was substantially higher than those values estimated from NRC ( 8 ) tables. DISCUSSION The prepartum DMI for cows in the current study were somewhat lower than those reported by Bertics et al. ( 1 ) and Van Saun et al. (11). This difference might partially account for the less severe prepartum decline in DMI, particularly compared with the DMI data for multiparous cows reported by Bertics et al. ( 1 ) . Nevertheless, cows in the current study did suffer a decline in DMI of approximately 15% [vs. 40% for Bertics et al. ( 1 ) ] between 10 d prepartum and calving. There was no difference in prepartum DMI between treatment groups. Despite the lack of difference in prepartum DMI between treatments, cows supplemented with yeast culture appeared to be in better energy balance, as was evidenced by the lower loss of body condition. However, as in the prepartum period, there was no influence of added yeast culture on DMI or intake of components of the DM. Cows in both treatment groups had a higher output of NEL than would have been expected based on intakes of the individual ingredients and their estimated ( 8 ) NEL values. This result suggests that the energy values of the ingredients were underesti-

TABLE 5. Milk yield and composition as influenced by yeast culture supplementation prepartum and postpartum. Contrast1

Treatment Yeast Control culture

Treatment × time

Treatment

SEM

P Yield, kg/d Milk Fat Protein Lactose Composition, % Fat Protein Lactose

34.09 1.38 1.07 1.52

34.65 1.46 1.09 1.60

0.76 0.36 0.72 0.42

0.62 0.76 0.54 0.74

0.43 0.03 0.01 0.02

4.17 3.26 4.51

4.33 3.19 4.60

0.43 0.44 0.25

0.62 0.03 0.26

0.08 0.03 0.02

1Time was significant ( P < 0.05) for all parameters except fat yield. Time is expressed as week postpartum for all parameters.

mated, that the use of change in BCS underestimated energy available from mobilized body stores, or that the metabolic efficiency was higher than expected in these early lactation cows based on reference to NRC ( 8 ) values. The first possibility is unlikely because the NRC ( 8 ) values have been validated several times, making an underestimate of such a high degree extremely unlikely. The second possibility would mean that energy mobilized from body stores would have had to be underestimated by approxi-

TABLE 6. Postpartum energy status as influenced by yeast culture supplementation prepartum and postpartum. Treatment Yeast Control culture

Contrast1 TreatTreat- ment ment × time

SEM

P Energy input, Mcal/d 28.33 Total2 Energy output, Mcal/d Milk 24.69 Maintenance 10.17 Body change –3.39 Total 31.51 Dietary energy density, Mcal/kg of DM 1.63 Estimated2 Calculated3 1.84

Figure 4. Milk yield by day postpartum for cows in the control ( ♦) and yeast culture ( ◊) groups (SEM = 0.43 kg/d). Journal of Dairy Science Vol. 80, No. 6, 1997

28.72

. . .

. . .

. . .

25.98 10.12 –3.17 33.11

0.38 0.86 0.78 0.33

0.71 0.76 0.83 0.99

0.39 0.03 1.09 1.15

1.63 1.90

. . . 0.31

. . . 0.98

. . . 0.07

1Time was significant ( P < 0.05) for milk, maintenance, and total energy output but was not significant ( P > 0.05) for body change energy and dietary energy density. Time is expressed as week postpartum for all parameters. 2Estimated from NRC ( 8 ) values. 3Calculated from total energy output and DMI.

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mately 60% based on changes in BCS, which seems implausible. Thus, higher metabolic efficiency was at least partially responsible for the high calculated energy density of the diet. The failure of yeast culture to alleviate the depression in DMI of the cows immediately prior to calving appears to support the hypothesis that the prepartum decline in DMI is not a rumen-mediated process. The alternate hypothesis, that the decline in DMI immediately prepartum resulted from a change in intermediary metabolism, perhaps caused by an inability to absorb nutrients from the forestomachs, appears to be supported. However, the data are equivocal because DMI of the cows in the prepartum period was low relative to that reported in other studies (1, 11). This lower DMI might have reduced the extent of the decline in DMI, thereby limiting the ability of the added yeast culture to alleviate it. In this context, DMI was substantially higher on the day of calving for cows supplemented with yeast culture, but these cows were unable to sustain the higher initial rate of increase in DMI postpartum. ACKNOWLEDGMENTS The authors thank K. Livingstone, A. Fletcher, and M. Woods for silage preparation; R. Mundle, D. Burnett, S. Rynax, A. Nason, and L. Dalton for cow care; D. Adamson for concentrate preparation; M. Corning for study organization; J. Keough, J. LaPointe, M. Corning, L. Stevens, and G. Allen for sample analyses; Diamond V Mills Inc. (Cedar Rapids, IA) for partial funding; and D. Cormier and M. Ingraham for typing the manuscript.

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