Dehydrated Alfalfa as a Concentrate Substitute in Rations of Lactating Dairy Cows

Dehydrated Alfalfa as a Concentrate Substitute in Rations of Lactating Dairy Cows B. K. K I R K P A T R I C K , D. A. C H R I S T E N S E N , and M. I. C O C H R A N Department of Animal and Poultry Science University of Saskatchewan Saskatoon, Saskatchewan S7N 0W0 ABSTRACT

INTRODUCTION

Dehydrated alfalfa was evaluated in a voluntary intake and digestibility trial, a steer growth trial, and lactating dairy cow production trial. The dehydrated alfalfa used in these trials contained 17.6% crude protein (dry matter), 1.26% calcium, .29% phosphorus, and 37.2% acid detergent fiber. Dry matter digestibility was 50.8%, and digestibility of crude protein was 50.4%. When 100 to 180-kg Holstein steers were fed brome-alfalfa hay pellets, 50% dehydrated alfalfa pellets and 50% chopped hay, or 50% dehydrated alfalfa pellets/50% barley grain pellets in a double 4 x 4 Latin square feeding trial, rates of gain on the all forage ratios were similar (.95 to 1.1 kg daily) and about 18% lower than on dehydrated alfalfa-barley pellets. In the dairy production trial, feeds used in digestion and steer growth trials were utilized in a replicated 4 × 4 Latin square. Rations consisted of 50% chopped brome-alfalfa hay and 50% concentrate. The four concentrates contained 0, 15, 30, or 45% dehydrated alfalfa pellets. Milk fat percentage was 10% higher when the 45% dehydrated alfalfa concentrate was fed. Total dry matter intakes were similar on all rations (20.2 to 21.2 kg daily), and body weight gains were not different (.47 to .59 kg gain daily). Dry matter digestibility was reduced to 60.8% for the 45% dehydrated concentrate feeding regimen from 62.3% for the control ration. In this feeding trial up to 45% dehydrated alfalfa pellets was included in the concentrate (22.5% of total ration) without detrimental effects on milk yield and composition or body weight.

In (6) dehydrated alfalfa (dehy) was fed to replace 3 or 6 kg of concent-rate dry matter in rations of lactating dairy cows. Milk yield was maintained by the dehy rations, and milk fat percentage tended to increase resulting in a slight (P<.IO) increase of 4% fat-corrected milk (FCM) yield. These results were similar to those of Blosser et al. (5) but in contrast to those of Hope et al. (8), who found a reduction in 4% FCM yield when 15 to 45% of the grain was replaced by chopped dehydrated grass legume forage. We intended to collect further information on the effect of dehy pellets included in the concentrate on milk yield and composition and to relate these effects to availability of dehy energy, rumen fermentation, and metabolic changes. Osborn et al. (14) showed that at moderate intakes, pelleting of forages improves utilization of net energy.

Received November 17, 1983. 1984 J Dairy Sci 67:2315-2320

MATERIALS AND METHODS

Two steer feeding trials were conducted to determine feeding value of dehy in relation to other feeds. These consisted of voluntary intake and digestibility trial and growth trial. In addition, a dairy cow production trial had four percents of dehy in the concentrate. Digestibilities of control and high dehy rations were measured. Digestibility and voluntary intake of dehy pellets, 50% dehy/50% barley grain pellets, and chopped brome-alfalfa hay were measured by 250 to 300 kg growing Hereford steers by methods in (7). The dehy and dehy/barley pellets were 6 mm in diameter. The dehy represented average quality dehy produced by the Tisdale alfalfa dehy processing plant (Table 1). The four steers fed each ration were kept in individual floor pens, fed each ration for 14 days, and restricted to maintenance feed intake to determine voluntary intake. During the final 10 days of the digestion trial, steers were housed in metabolism crates and restricted to their maintenance intake of energy. Feces were col2315

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KIRKPATRICK ET AL.

TABLE 1. Composition of feeds evaluated by steer digestibility. Dehydrated alfalfa (dehy) pellets

Brome-alfalfa hay

50:50 Dehy/barley pellets

(dry matter) Dry matter, % Crude protein, % Calcium, % Phosphorus, % Acid detergent fiber Gross energy, Mcal/kg

90.5 17.6 1.26 .29 37.2 4.56

94.1 13.3 .63 ,41 41.2 4.47

lected quantitatively during the final 5 days and a 5% sample was collected for drying (60°C for 48 h), grinding, and subsequent analysis by standard methods (7). The Holstein steer growth trial was a replicated 4 x 4 Latin square design with 60-day feeding periods. The four rations consisted of the three evaluated in the steer digestibility trial plus 50% dehy/50% alfalfa hay pellets (6 mm diameter). A dicalcium phosphate supplement containing 30% trace mineralized salt was available to all animals and was limited to 100 g per steer daily. Holstein steers averaged 100 to 180 kg at the start of the trial. Body weights and feed intake over the last 35 days of each feeding period were used to assess steer performance. The dairy production trial consisted of a replicated 4 x 4 Latin square trial with 35-day feeding periods. Rations consisted of 50% chopped brome-alfalfa hay (used in digestibility and steer growth trials) and 50% concentrate containing 0, 15, 30, or 45% dehy pellets. The

89.2 14.8 .67 .38 26.0 4.62

nondehy portions of the concentrate were pelleted (6 mm diameter) and were mixed with an appropriate amount of dehy for each cow at each feeding. The concentrates were formulated to meet National Research Council 1971 (12) nutrient requirements and contained nutrients in Table 2 in the nondehy portion of the concentrate. Major nondehy components of the concentrate were barley (67 to 73%), wheat (10 to 18%), soybean meal (1.4 to 3.0%), and canola meal (2.8 to 6%). Calcium and phosphorus were adjusted by inclusion of dicalcium phosphate, limestone, and sodium tripolyphosphate. A premix supplying vitamins A, D3, and E and copper, manganese, and zinc also was added. Milk from the last six milkings in each period was composited and analyzed for fat and protein (1) and total solids by the gravimetric method (3). Rumen fluid was obtained by stomach tube about 4 h after morning feeding and prepared and analyzed for volatile fatty acids (VFA) as described by Kellogg (9). Blood samples drawn 2 h after

TABLE 2. Composition of feeds in the dairy production trial.

Dry matter

Crude protein

Calcium

13.3 17.6 16.4 15.6 15.5 16.5

.63 1.26 .78 .59 .43 .10

(%) Alfalfa-bromegrass hay Dehydrated alfalfa (dehy) 0% Dehy concentrate 15% Dehy concentrate 30% Dehy concentrate 45% Dehy concentrate

88.5 89.1 86.7 86.8 86.7 86.6

Phosphorus

Acid detergent fiber

(% in dry matter)

Journal of Dairy Science Vol. 67, No. 10, 1984

.41 .29 1.03 1.24 1.38 1.85

Gross energy (Mcal/kg)

42.9 38.3 7.5 7.4 7.5 8.0

4.47 4.66 4.51 4.48 4.57 4.50

DEHYDRATED ALFALFA FOR LACTATING COWS

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TABLE 3. Digestibility of feeds by steers. Dehydrated alfalfa (dehy) pellets

Brome-alfalfa hay

50:50 Dehy/barley pellets

SE

63.8 a 69.g a 38.5 c 64.0 a

.96 1.60 1.06 .95

(%) Dry matter Crude protein Acid detergent fiber, % Energy

69.2 a 71.9a

50.8b 50.4b 44.2 b 48.7 b

66.7 a

64.7 a

a'b'CMeansin the same row followed by different letters differ (P<.05).

morning feeding were analyzed for hematology and blood chemistry by the Pathology Laboratory, Western College of Veterinary Medicine. Apparent digestibility of the control and 45% dehy concentrate rations was determined in a separate trial with an additional six lactating cows in a crossover design resulting in six observations on each ration. Chromic oxide equivalent to .3% of the total ration dry matter was fed in the concentrate pellets. Alfalfabromegrass hay was fed as half of the ration, and total feed intake was slightly restricted. Rations were fed for a 2-wk adjustment followed by 8-day fecal collection during which feces were collected and sampled twice daily. Fecal samples were analyzed according to methods of the Association of Official Agricultural Chemists (3). Statistical analyses were according to Snedecor and Cochran (15).

RESULTS AND DISCUSSION

Digestibilities of dry matter, energy, crude protein, and acid detergent fiber (ADF) in the dehy pellets were significantly lower than those of the alfalfa-bromegrass hay, which contained more ADF and iess protein (Table 3). The dehy digestible energy [2.27 Mcal/kg dry matter (DM)] was also lower than the 2.69 Mcal/kg DM reported by the National Research Council 1978 (13). It is, however, similar to the 51.1% energy digestibility [2.32 Mcal digestible energy" (DE)/kg DM)] reported by Anderson et al. (2). In this trial, the dehy was higher in ADF than is typical for Western Canada. The inclusion of 50% ground barley in the dehy pellets increased digestibilities (P<.05) of dry matter, energy, and protein but decreased digestibility of ADF. Average daily gain of growing steers (Table 4) fed dehy was 15.8% higher than when

TABLE 4. Performance and nutrient utilization by dairy steers. 100%

Avg daily gain, kg/day Feed dry matter intake, kg/day Feed/gain Estimated digestible energy intake, Meal/day

100% Hay

Dehydrated alfalfa (dehy)

50:50 Dehy/hay

50:50 Dehy/batley

SE

.95 6.34d 6.8ab 19.7

1.10 8.18a 7.6 a 18.2

1.08 7.41b 7.0a 18.9

1.26 6.80c 5.4b 20.2

.10 1.84 .47 1.22

a'b'CMeansin the same row followed by different letters differ (P<.05). Journal of Dairy Science Vol. 67, No. 10, 1984

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TABLE 5. Milk yield and composition. Portion of concentrate replaced with dehydrated alfalfa Item

0%

15°6

30%

45%

Milk yield, kg/day Milk fat, % Milk fat, kg/day 4% fat-corrected milk (FCM) yield, kg/day Persistency of fat-corrected milk yield, % Total solids, % Milk total solids, kg/day Milk solids-not fat, % Milk solids-r.ot fat, kg/day Milk protein, % Milk protein, kg/day Dry matter intake/100 kg 4% FCM, kg

25.33 3.20 .77

24.88 3.34 .78

25.29 3.48 .85

24.90 3.54 .87

22.0

21.6

23.5

23.0

1.90

89 11.62 2.92 8.47 2.14 3.46 .866

81 11.72 2.84 8.36

88 11.83 3.02 8.36 2.13 3.44 .874

84 11.93 2.96 8.39 2.09 3.47 .848

2.50 .18 .09 .08 .08 .05 .029

99

97

95

99

3.62

2.07

3.48 .844

alfalfa-bromegrass hay was fed, but the difference was n o t significant (P>.05). Feed intake was highest w h e n dehy was fed and lowest when hay was fed. Efficiency of feed utilization was n o t different for the three all-forage rations b u t was significantly improved w h e n 50% d e h y / 5 0 % barley grain was fed. The t e n d e n c y for faster gain and m o r e efficient feed use in the 50% harley grain t r e a t m e n t m a y have been related to a slightly higher (11%) estimated intake of DE (P>.05). Milk fat percentage was increased by 10.6%, and 4% FCM increased 4.5% by feeding 45% dehy in the concentrate c o m p a r e d with 0% dehy control, but no ration effects (P>.05) on milk yield and c o m p o s i t i o n were significant (Table 5). This is in contrast to a trial where a

SE .87 .135 .042

slight (P<.10) increase of 4% FCM yield occurred w h e n 6.0 kg of d e h y was fed daily (6). Maintenance of milk yield and rate of b o d y weight gain occurred w i t h o u t significant increase of dry m a t t e r intake (Table 7). Inclusion of 45% d e h y in the c o n c e n t r a t e (22.5% of total ration dry matter) resulted in a smaller than e x p e c t e d reduction (based on the steer digestibility trial) of digestibility of the 45% dehy concentrate ration (Table 6). The 3% r e d u c t i o n of digestible energy percentage of the total ration was n o t significant (P>.05). All rations maintained a daily weight gain of .47 kg daily or more, and, hence, energy intake did n o t appear to be limiting. T o t a l ruminal V F A increased by 5.2% w h e n 45% dehy c o n c e n t r a t e was fed (P>.05), and

TABLE 6. Digestibility of 0% dehydrated alfalfa (dehy) and 45% dehy rations fed to lactating cows.

Feed intake, kg dry matter/day Digestibility, % Dry matter Energy Crude protein Acid detergent fiber

Journal of Dairy Science Vol. 67, No. 10, 1984

0% dehy ration

45% dehy ration

16.8

18.1

62.3 62.4 63.2 42.6

60.8 60.6

63.0 43.9

SE

1.37 1.24 1.67 1.25

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DEHYDRATED ALFALFA FOR LACTATING COWS TABLE 7. Feed utilization by lactating dairy cows according to dehydrated alfalfa (dehy) fed. Portion of concentrate replaced with dehy

Hay intake, kg dry matter/day % of total dry matter Dehy intake, kg dry matter/day % of total dry matter Concentrate intake, kg dry matter/day % of total dry matter Total dry matter/day, kg Crude protein intake, kg Estimated total digestible nutrient intake, % of requirement 1 Weight change, kg/day

0%

15%

30%

45%

SE

12.2 55.7

11.0 51.1

11.3 52.0

11.4 52.1

.39 1.87

1.6 b 7.7 b

3.0 c 14.3 c

4.8d 21.7 d

.17 .61

8.2 a 41.3 a 20.2 2.68

6.9 b 33.7 b 21.2 2.91

5.4 c 26.2 c 21.2 2.86

.46 1.92 .55 .07

0a 0a 8.5 a 43.9 a 20.9 2.83 111

109 .48

115 .56

111 .47

.59

.49 .06

a'b'c'dMeans in the same row followed by different letters differ (P<.05). Based on 1971 (12) dairy requirement estimates and total digestible nutrients for dehy and hay from the steer digestibility trial or (1969) (11) tables of feed composition.

m o l a r p e r c e n t a g e o f p r o p i o n a t e was r e d u c e d b y 14% ( P < . 0 5 ) , resulting in a significant increase o f ratio o f acetate to p r o p i o n a t e and a slight increase o f t o t a l acetate (Table 8). Baldwin and S m i t h (4) o b s e r v e d t h a t additional a c e t a t e is used e f f i c i e n t l y f o r milk fat synthesis. It also was o b s e r v e d b y O s b o r n et al. (14) t h a t pelleted forages yielded greater t h a n e x p e c t e d n e t energy.

N o m a j o r e f f e c t s o n b l o o d c h e m i s t r y or h e m a t o l o g y (Table 9) were observed. Blood urea n i t r o g e n and plasma p h o s p h o r u s were m a i n t a i n e d b y the d e h y c o n c e n t r a t e s . Similar u n e x p l a i n e d variation o f p e r c e n t m o n o c y t e s was in (10). This feeding trial indicates t h a t up to 45% d e h y alfalfa can be included in t h e c o n c e n t r a t e (22.5% in t h e total ration) w i t h o u t d e t r i m e n t a l

TABLE 8. Ruminal volatile fatty acids in lactating cows according to dehy fed. Portion of concentrate replaced with dehy

Total volatile fatty acids, V.M/ml Volatile fatty acids, molar % Acetate Propionate Butyrate lsovalerate Valerate Acetate:propionate ratio (molar %)

0%

15%

30%

45%

SE

90.3

96.1

93.3

95.0

3.7

57.2 30.0 a 8.8 2.3 1.7 1.99 b

57.3 28.7 a 9.4 2.7 2.0 2.06 ab

62.4 26.0 b 9.0 1.4 1.1 2.41 a

61.9 25.9 b 8.8 2.0 1.4 2.40 a

1.18 1.27 .36 .41 .26 .11

a'bMeans in the same row followed by different letters differ (P<.05). Journal of Dairy Science Vol. 67, No. 10, 1984

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TABLE 9. Blood chemistry and hematology of lactating cows fed dehydrated alfalfa (dehy). Portion of concentrate replaced with dehy

Calcium, mg/1 O0 ml plasma Phosphorus, m g / 1 0 0 ml plasma Magnesium, m g / l O 0 ml plasma Urea nitrogen, m g / l O 0 ml blood Glucose, m g / l O 0 ml plasma Hemoglobin, g/lO0 ml Packed cell volume, % White blood cells, x l O 3 / m m 3 Lymphocytes, % Monocytes, %

0%

15 %

30%

45%

SE

9.8 6,2 2.28 b 14.5 61.5 12.3 33.0 8.3 51.1 5.0 a

9.6 6.4 2.33 b i3.9 60.8 11.9 32.4 7.7 52.7 5.1 a

9.5 6.2 2.49 a 15.1 60.2 11.9 32.2 8.2 54.0 4.0 ab

9.4 7.0 2.31 b 15.8 59.5 11.5 31.7 7.9 55.0 2.8 b

.16 .35 .04 .66 1.52 .40 .55 .21 2.10 .55

a'bMeans in the same row followed by different letters differ (P<.05).

effects on milk yield or composition and with maintenance of normal ruminal function and metabolic characteristics. REFERENCES

1 American Public Health Association. 1960. Standard m e t h o d s for the examination of dairy products microbiological and chemical. Am. Publ. Health Assoc., New York, NY. 2 Anderson, D. M., D. A. Christensen, and G. I. Christison. 1977. Voluntary intake and digestibility of slough h a y and dehydrated alfalfa pellets by rams and steers. Can. J. Anim. Sci. 57:609. 3 Association of Official Agricultural Chemists. 1975. Methods of analysis. 12th ed. Assoc. offic. Agric. Chem., Washington DC. 4 Baldwin, R. L., and N. E. Smith. 1979. Regulation of energy metabolism in ruminants. Pages 1 - 27 in Advances in nutritional research. Vol. 2. H. H. Draper, ed. Plenum Publ. Co., New York, NY. 5 Blosser, T. H., F. R. Murdock, R. E. Lintott, R. E. Erb, and A. O, Shaw. 1952. The use of dehydrated forages in dairy cattle rations. II. Comparative values of finely ground, chopped and pelleted dehydrated alfalfa as grain replacements for lactating dairy cows. J. Dairy Sci. 35:515. 6 Christensen, D. A., and M. I. Cochran. 1983. Composition and nutritive value of dehydrated alfalfa for lactating dairy cows. J. Dairy Sci.

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66:1282. 7 Christensen, D. A., B. D. Owen, G. Steacy, W. L. Crowle, and J. P. Mtimuni. 1977. Nutritive value of whole crop silage made from seven cereal cuhivars. Can. J. Anita. Sci. 57:537. 8 Hope, E. B., R. E. Erb, T. H. Blosser, U. S. Ashworth, and A. O. Shaw. 1950. The use of dehydrated forage in dairy cattle rations. I. Grain substitution with finely ground material. J. Dairy Sci. 33:306. 9 Kellogg, D. W. 1969. Analysis of r u m e n fluid volatile fatty acids by chromatography with porapak QS. J. Dairy Sci. 52:1690. 10 Laarveld, B., and D. A. Christensen. 1976. Rapeseed meal in complete feeds for dairy cows. J. Dairy Sci. 59:1929. 11 National Research Council. 1969. United States Canadian tables of feed composition. Natl. Acad. Sci., Washington DC. 12 National Research Council. 1971. Nutrient requirements o f dairy cattle. Natl. Acad. Sci., Washington DC. 13 National Research Council. 1978. Nutrient requirements of dairy cattle. Natl. Acad. Sci., Washington DC. 14 Osborn, D. F., D. E. Beever, and D. J. T h o m s o n . 1976. The influence of physical processing on the intake, digestion and utilization of dried herbage. Proc. Nutr. Soc. 35:191. 15 Snedecor, G. W., and W. G. Cochran. 1967. Statistical methods. 4th ed. Iowa State Univ. Press, Ames.