Effects of Sodium Carbonate on Milk Yield, Milk Composition, and Blood Components of Dairy Cows in Early Lactation N. G. BELIBASAKIS Department of Animal Husbandry Faculty of Veterinary Medicine A. TRIANTOS Department of Biological Chemistry Faculty of Medicine University of Thessaloniki Greece INTRODUCTION
ABSTRACT
In early lactation, high producing dairy cows often fail to consume sufficient feed and generally are in negative energy balance. Increasing the proportion of concentrates above 60% of total ration DM to provide higher energy density may result in many problems such as anorexia, rumen acidosis, reduction in forage digestibility, milk fat depression, and possible increase in the incidences of abomasal displacement, milk fever, and ketosis (6). The addition of dietary buffers such as NaHCO3, KHCO3, sodium sesquicarbonate (Na2C03.NaHCO3.2H20), K2CO3, and Na2C03 to high concentrate, restricted-forage diets of cows in early lactation could be beneficial for milk production. Dietary buffers irnprove feed intake (especially forage) (8, 12); increase rumen fluid pH, fluid dilution rate, digestibility of dietary nutrients, acetate:propionate ratio, and the rate of passage of fluids from the rumen; and maintain the pH in intestines, tissues, and body fluids (11, 15, 18). These effects optimize metabolic functions for milk production in dairy cows and often increase milk yield (12, 19), milk fat percentage (5, 10, 24), or milk protein percentage (13). The most significant responses of dairy cows to dietary buffers have been reported when corn silage was the sole or major forage in the diet (5, 14, 19). However, variable responses have been observed when cows were fed haycrop silage or Abbreviation key: AA = acetate, BHBA = fb alfalfa hay (1, 3, 9). hydroxybutyrate, CF = crude fiber, TG = triThe objective of this experiment was to glycerides, TS = total solids. evaluate the response of dairy cows to the addition of Na2C03 to high concentrate, low alfalfa hay diets in early lactation. The traits investigated were milk yield and composition, Received April 26,1990. DMI, and blood plasma metabolites plus Na Accepted September 4, 1990. Eighteen multiparous Friesian cows were piLed according to lactation number and expected calving date and assigned randomly to one of two diets in a crossover design experiment to study effects of sodium carbonate on milk yield, milk composition, blood metabolites plus Na, and K in early lactation. Diets were concentrate containing either 0 or 1.2% sodium carbonate (as fed) for ad libitum intake plus 7.0 kg of wet brewers grains and 5.5 kg of long-stemmed alfalfa hay per cow daily. Dry matter intake, milk yield, milk protein percentage and yield, and percentages of milk lactose and milk SNP were not significantly affected. Compared with the control diet, the sodium carbonate treatment increased milk fat percentage (3.98 vs. 3.53%) and yield (1.23 vs. 1.07 kg/d), 4% FCM yield (30.9 vs. 28.2 kg/d) and milk total solids (12.47 vs. 12.04%). No significant differences were observed in blood plasma concentrations of glucose, CP, urea, acetate, phydroxybutyrate, triglycerides, ITA, Na, or K when sodium carbonate was added to diets for early lactation cows. (Key words: sodium carbonate, lactation, blood metabolites)
1991 I Dairy Sci 74:467-472
467
468
BELIBASAKIS AND TRIANTOS
and K. Sodium carbonate was used because 1) it is strongly alkaline in aqueous solution and has powerful neutralizing properties, 2) in vivo studies with Na2CO3 alone have not been previously conducted, and 3) it is the most inexpensive of the common neutcalizers in Greece. MATERIALS AND METHODS Physlcal and Chemical Properties of Sodium Carbonate
intake plus 7.0 kg of wet brewers grains and 5.5 kg of long-stemmed alfalfa hay per cow daily. Chemical composition of concentrate mixtures, alfalfa hay, and wet brewers grains, as well as the ingredients of concentrate mixtures, are shown in Table 1. The cows remained on trial from wk 2 prepartum until wk 11 postpartum. The 2 wk prepartum and the first 3 wk postparnun were the adjustment p e r i d The following 8 wk postpartum included two experimental periods of 4 wk each. Daily rations averaged 4.0, 5.5, 7.0, 10.0, and 12.0 kg of concentrate mixture without Na2CO3 (control diet) during wk 2 and 1 prepamUn and Wk 1,2, and 3 postpartum, respectively, plus 7.0 kg of wet brewers grains and 5.5 kg of alfalfa hay. During the first experimental period (wk 4 to 7 postpartum), one cow from each of the nine pairs was fed the control diet; the other cow received the diet with Na2CO3. For the second experimental period (wk 8 to 11 postpartum), all cows were switched to the opposite diet. Cows were adjusted to experimental diets at wk 4 and 8 postpartum, for the first and second period, respectively. Dunhg the adjustment and experimental periods, rations were balanced to meet NRC requirements (15). The cows were tied in stalls at all times, fed individually, and milked at 0600 and 1700 h. Feed refusals were removed daily before the a.m. feeding. Water was available for the cows at all times. The concentrations of Na and K in the drinking water were 15.5 and 2.5 ppm, respectively.
The commercially supplied Na2C03 that was added in the experimental diet was a white powder of bitter taste with the following percentage composition: Na2C03, 99.4;NaC1, .4; Na2SO4, .03; G O , .02;MgO,.01; FQO~,.002; and loss on ignition, .138. The total concentration of Na in this compound was approximately 43.4% (by weight). At ambient temperature, the water solubility of Na2C03 was 22 ddl, and the pH measured in aqueous solution at the concentration of 1.2 g/dl was 11.3. During the experiment, 1.2% Na2CO3 were included in the concentrate as fed. The physical form of the resulting concentrate mixture, which was stored in bags for 2 mo, did not change. The incorporation of 1.2% Na2CO3 in the concentrate provided Na concentration theoretically equal to that of 1.9% NaHCO3 and bicarbonate (JiIC.03) by weight equal to that of 1.6% K2CO3, 1.9% NaHCO3, or 2.2% KHC03. This is due to the C03 ion’s capacity to absorb hydrogen ions to form the HCO3 ion. Thus, although the concentration by weight of C03 ions in Na2CO3 or K2CO3 is approximately Sample Collection and Analyses half that of HCO3 ions in NaHCO3 or KHCO3, Milk yield was recorded at each milking these compounds theoretically are equal in their during wk 6 and 7 of the first experimental capacity to absorb hydrogen ions. period and during wk 10 and 11 of the second period. Milk samples were taken at each milking during the last 3 d of each period and Experimental Animals and Dlets analyzed for total solids (TS), fat, SNF, CP, Eighteen multiparous Friesian cows weigh- and lactose using a milk analyzer (Milco Scan ing approximately 600 kg were paired accord- 104 A / s N. Foss Electric. Millcoscah, Dening to expected calving date and lactation num- mark). ber and assigned randomly to one of two diets Samples of alfalfa hay and wet brewers in a crossover design experiment (7). The two grains were taken weekly, and samples of feed experimental diets were concentrate containing ingredients in concentrate mixtures were taken either 0 or 1.2% Na2CO3 (as fed) for ad libitum during mixing. The samples of feed were anaJournal of Dairy Science Vol. 74, No. 2, 1991
469
SODIUM CARBONATE FOR LACTATING COWS
RESULTS AND DISCUSSION lyzed for DM, CP, and crude fiber (CF)according to AOAC procedures (2). Blood samples were drawn from the tail Feed Intake vein into heparinized centrifuge tubes on the Mean daily DMI (Table 2) was unaffected last day of each experimental period at about 4 by treatment during early lactation of cows, h postfeeding and centrifuged. Plasma was although daily intake of concentrate mixture stored at -2o'C until analyzed for glucose, CP, containing Na2CO3 was approxhately .4 kg/d acetate (AA), B-hydroxybutyrate (BHBA), urea (Test, Boehringer Mannheim Diagnostica, Ger- lower than for control diets during wk 1 of each many), triglycerides (TG) (Test, Sclavo Diag- experimental period when cows were adjusting nostica, Italy), FFA (17). and Na and K by to diets. Similar results have been reported in flame photometry (Flame Photometer, Epe- studies with the addition of NaHCO3 to diets containing long-stemmed alfalfa hay as the sole dorph, Germany). or major forage (1, 20). Newbold et al. (16) reported that the supplementation of NaHCO3 Statlstlcal Analysis to diets containing grass silage and molasses had no effect on the DMI of primiparous cows The experimental design was a crossover with cows randomly assigned to treatments (7). in early lactation. Edwards and Poole (8) obMilk yield, milk composition, DM intake served an increase in hay intake, whereas Tho@ha) of concentrate mixtures, and blood mas and Emery (22) and Eickelberger et al. (9) plasma components were tested by ANOVA found that concentrate intake decreased when using the Minitab Statistical Package (21) in an NaHCO3 was added to the diet. Our results Amstrad computer (PC 1640, UK). Effects suggest that the incorporation of 1.2% Na2CO3 were considered significantly different at in the concentrate had no adverse effects on the intake of cows in early lactation. Pc.05.
TABLE 1. Chemical Composition of concentrate mixtures, alfalfa hay, and brewers grains. and ingredients of concentrate mixtures.
Concentrate Trait
Conlrol
Na2C03
Alfalfa hay
Brewers
grains
chemical analysis'
DM, 46
88.0
CP, % crude. fiber, 46
16.0
w,2 Mcal/kg
88.9
15.9
4.3
4.2
1.62
1.64
902 21.9 23.5 1A
30.0 24.0 14.3 1.5
(46)
Ingredients3
Ground corn Cottonseed meal soybean meal Molasses Dicalcium phosphate Minerat and vitamin mix4 Salt
odium carbonate Total
67.0
15.0 13.0 2.0 1.o 1.5
65.8 15.0 13.0 2.0 1.o 1.5
.5
5
100.0
12 100.0
...
DM basis
except DM. calculated as in NRC guidelines (15). 3As fed. %g, .9% Mn, .996; Pe, .8%2i1,.6% CU 0 8 % I, .03%; Co, .W% vitamin A, 1.200,OOO IU/kg vitamin D, 260,OOO IU&; and vitamin E, 1500 IU/kg.
Journal of Dairy Science Vol. 74. No. 2, 1991
470
BELIBASAKIS AND TRIANTOS
TABLE 2. Average DMI, milk productior~,aud milk composition of
the d B m t
Control
Item
Intalre
Total DMI, kgfd Concentrate DMI, kg/d Brewers g m h DMI, kg/d Alfalfa hay DMI, wd Milk production Actual milk yield, kgfd 4% FCM yield kg/d Fat yield, kgfd protein yield, kg/d Milk composition Total solids, % pat, % SNP, 96 Rotein, % Lactose, 96
19.7 12.8 2.o
4.9
30.4 289 1.07b
.86 12.d 3.53d 8.51
2.82 4.94
di-. Diets Na2C03
SE
19.8
...
12.9 2.0 4.9
... ...
31.0 30.98
1.o 1.o .06
1.23= .88
.1
.04
12.47' 3.98=
.17 .13
8.49 2.83
.09 .06
4.90
.M
8.bPC.05. C*dP
ABSTRACT
In early lactation, high producing dairy cows often fail to consume sufficient feed and generally are in negative energy balance. Increasing the proportion of concentrates above 60% of total ration DM to provide higher energy density may result in many problems such as anorexia, rumen acidosis, reduction in forage digestibility, milk fat depression, and possible increase in the incidences of abomasal displacement, milk fever, and ketosis (6). The addition of dietary buffers such as NaHCO3, KHCO3, sodium sesquicarbonate (Na2C03.NaHCO3.2H20), K2CO3, and Na2C03 to high concentrate, restricted-forage diets of cows in early lactation could be beneficial for milk production. Dietary buffers irnprove feed intake (especially forage) (8, 12); increase rumen fluid pH, fluid dilution rate, digestibility of dietary nutrients, acetate:propionate ratio, and the rate of passage of fluids from the rumen; and maintain the pH in intestines, tissues, and body fluids (11, 15, 18). These effects optimize metabolic functions for milk production in dairy cows and often increase milk yield (12, 19), milk fat percentage (5, 10, 24), or milk protein percentage (13). The most significant responses of dairy cows to dietary buffers have been reported when corn silage was the sole or major forage in the diet (5, 14, 19). However, variable responses have been observed when cows were fed haycrop silage or Abbreviation key: AA = acetate, BHBA = fb alfalfa hay (1, 3, 9). hydroxybutyrate, CF = crude fiber, TG = triThe objective of this experiment was to glycerides, TS = total solids. evaluate the response of dairy cows to the addition of Na2C03 to high concentrate, low alfalfa hay diets in early lactation. The traits investigated were milk yield and composition, Received April 26,1990. DMI, and blood plasma metabolites plus Na Accepted September 4, 1990. Eighteen multiparous Friesian cows were piLed according to lactation number and expected calving date and assigned randomly to one of two diets in a crossover design experiment to study effects of sodium carbonate on milk yield, milk composition, blood metabolites plus Na, and K in early lactation. Diets were concentrate containing either 0 or 1.2% sodium carbonate (as fed) for ad libitum intake plus 7.0 kg of wet brewers grains and 5.5 kg of long-stemmed alfalfa hay per cow daily. Dry matter intake, milk yield, milk protein percentage and yield, and percentages of milk lactose and milk SNP were not significantly affected. Compared with the control diet, the sodium carbonate treatment increased milk fat percentage (3.98 vs. 3.53%) and yield (1.23 vs. 1.07 kg/d), 4% FCM yield (30.9 vs. 28.2 kg/d) and milk total solids (12.47 vs. 12.04%). No significant differences were observed in blood plasma concentrations of glucose, CP, urea, acetate, phydroxybutyrate, triglycerides, ITA, Na, or K when sodium carbonate was added to diets for early lactation cows. (Key words: sodium carbonate, lactation, blood metabolites)
1991 I Dairy Sci 74:467-472
467
468
BELIBASAKIS AND TRIANTOS
and K. Sodium carbonate was used because 1) it is strongly alkaline in aqueous solution and has powerful neutralizing properties, 2) in vivo studies with Na2CO3 alone have not been previously conducted, and 3) it is the most inexpensive of the common neutcalizers in Greece. MATERIALS AND METHODS Physlcal and Chemical Properties of Sodium Carbonate
intake plus 7.0 kg of wet brewers grains and 5.5 kg of long-stemmed alfalfa hay per cow daily. Chemical composition of concentrate mixtures, alfalfa hay, and wet brewers grains, as well as the ingredients of concentrate mixtures, are shown in Table 1. The cows remained on trial from wk 2 prepartum until wk 11 postpartum. The 2 wk prepartum and the first 3 wk postparnun were the adjustment p e r i d The following 8 wk postpartum included two experimental periods of 4 wk each. Daily rations averaged 4.0, 5.5, 7.0, 10.0, and 12.0 kg of concentrate mixture without Na2CO3 (control diet) during wk 2 and 1 prepamUn and Wk 1,2, and 3 postpartum, respectively, plus 7.0 kg of wet brewers grains and 5.5 kg of alfalfa hay. During the first experimental period (wk 4 to 7 postpartum), one cow from each of the nine pairs was fed the control diet; the other cow received the diet with Na2CO3. For the second experimental period (wk 8 to 11 postpartum), all cows were switched to the opposite diet. Cows were adjusted to experimental diets at wk 4 and 8 postpartum, for the first and second period, respectively. Dunhg the adjustment and experimental periods, rations were balanced to meet NRC requirements (15). The cows were tied in stalls at all times, fed individually, and milked at 0600 and 1700 h. Feed refusals were removed daily before the a.m. feeding. Water was available for the cows at all times. The concentrations of Na and K in the drinking water were 15.5 and 2.5 ppm, respectively.
The commercially supplied Na2C03 that was added in the experimental diet was a white powder of bitter taste with the following percentage composition: Na2C03, 99.4;NaC1, .4; Na2SO4, .03; G O , .02;MgO,.01; FQO~,.002; and loss on ignition, .138. The total concentration of Na in this compound was approximately 43.4% (by weight). At ambient temperature, the water solubility of Na2C03 was 22 ddl, and the pH measured in aqueous solution at the concentration of 1.2 g/dl was 11.3. During the experiment, 1.2% Na2CO3 were included in the concentrate as fed. The physical form of the resulting concentrate mixture, which was stored in bags for 2 mo, did not change. The incorporation of 1.2% Na2CO3 in the concentrate provided Na concentration theoretically equal to that of 1.9% NaHCO3 and bicarbonate (JiIC.03) by weight equal to that of 1.6% K2CO3, 1.9% NaHCO3, or 2.2% KHC03. This is due to the C03 ion’s capacity to absorb hydrogen ions to form the HCO3 ion. Thus, although the concentration by weight of C03 ions in Na2CO3 or K2CO3 is approximately Sample Collection and Analyses half that of HCO3 ions in NaHCO3 or KHCO3, Milk yield was recorded at each milking these compounds theoretically are equal in their during wk 6 and 7 of the first experimental capacity to absorb hydrogen ions. period and during wk 10 and 11 of the second period. Milk samples were taken at each milking during the last 3 d of each period and Experimental Animals and Dlets analyzed for total solids (TS), fat, SNF, CP, Eighteen multiparous Friesian cows weigh- and lactose using a milk analyzer (Milco Scan ing approximately 600 kg were paired accord- 104 A / s N. Foss Electric. Millcoscah, Dening to expected calving date and lactation num- mark). ber and assigned randomly to one of two diets Samples of alfalfa hay and wet brewers in a crossover design experiment (7). The two grains were taken weekly, and samples of feed experimental diets were concentrate containing ingredients in concentrate mixtures were taken either 0 or 1.2% Na2CO3 (as fed) for ad libitum during mixing. The samples of feed were anaJournal of Dairy Science Vol. 74, No. 2, 1991
469
SODIUM CARBONATE FOR LACTATING COWS
RESULTS AND DISCUSSION lyzed for DM, CP, and crude fiber (CF)according to AOAC procedures (2). Blood samples were drawn from the tail Feed Intake vein into heparinized centrifuge tubes on the Mean daily DMI (Table 2) was unaffected last day of each experimental period at about 4 by treatment during early lactation of cows, h postfeeding and centrifuged. Plasma was although daily intake of concentrate mixture stored at -2o'C until analyzed for glucose, CP, containing Na2CO3 was approxhately .4 kg/d acetate (AA), B-hydroxybutyrate (BHBA), urea (Test, Boehringer Mannheim Diagnostica, Ger- lower than for control diets during wk 1 of each many), triglycerides (TG) (Test, Sclavo Diag- experimental period when cows were adjusting nostica, Italy), FFA (17). and Na and K by to diets. Similar results have been reported in flame photometry (Flame Photometer, Epe- studies with the addition of NaHCO3 to diets containing long-stemmed alfalfa hay as the sole dorph, Germany). or major forage (1, 20). Newbold et al. (16) reported that the supplementation of NaHCO3 Statlstlcal Analysis to diets containing grass silage and molasses had no effect on the DMI of primiparous cows The experimental design was a crossover with cows randomly assigned to treatments (7). in early lactation. Edwards and Poole (8) obMilk yield, milk composition, DM intake served an increase in hay intake, whereas Tho@ha) of concentrate mixtures, and blood mas and Emery (22) and Eickelberger et al. (9) plasma components were tested by ANOVA found that concentrate intake decreased when using the Minitab Statistical Package (21) in an NaHCO3 was added to the diet. Our results Amstrad computer (PC 1640, UK). Effects suggest that the incorporation of 1.2% Na2CO3 were considered significantly different at in the concentrate had no adverse effects on the intake of cows in early lactation. Pc.05.
TABLE 1. Chemical Composition of concentrate mixtures, alfalfa hay, and brewers grains. and ingredients of concentrate mixtures.
Concentrate Trait
Conlrol
Na2C03
Alfalfa hay
Brewers
grains
chemical analysis'
DM, 46
88.0
CP, % crude. fiber, 46
16.0
w,2 Mcal/kg
88.9
15.9
4.3
4.2
1.62
1.64
902 21.9 23.5 1A
30.0 24.0 14.3 1.5
(46)
Ingredients3
Ground corn Cottonseed meal soybean meal Molasses Dicalcium phosphate Minerat and vitamin mix4 Salt
odium carbonate Total
67.0
15.0 13.0 2.0 1.o 1.5
65.8 15.0 13.0 2.0 1.o 1.5
.5
5
100.0
12 100.0
...
DM basis
except DM. calculated as in NRC guidelines (15). 3As fed. %g, .9% Mn, .996; Pe, .8%2i1,.6% CU 0 8 % I, .03%; Co, .W% vitamin A, 1.200,OOO IU/kg vitamin D, 260,OOO IU&; and vitamin E, 1500 IU/kg.
Journal of Dairy Science Vol. 74. No. 2, 1991
470
BELIBASAKIS AND TRIANTOS
TABLE 2. Average DMI, milk productior~,aud milk composition of
the d B m t
Control
Item
Intalre
Total DMI, kgfd Concentrate DMI, kg/d Brewers g m h DMI, kg/d Alfalfa hay DMI, wd Milk production Actual milk yield, kgfd 4% FCM yield kg/d Fat yield, kgfd protein yield, kg/d Milk composition Total solids, % pat, % SNP, 96 Rotein, % Lactose, 96
19.7 12.8 2.o
4.9
30.4 289 1.07b
.86 12.d 3.53d 8.51
2.82 4.94
di-. Diets Na2C03
SE
19.8
...
12.9 2.0 4.9
... ...
31.0 30.98
1.o 1.o .06
1.23= .88
.1
.04
12.47' 3.98=
.17 .13
8.49 2.83
.09 .06
4.90
.M
8.bPC.05. C*dP
