Agricultural and Food Science in Finland, Vol. 12 (2003): 83–93 83 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Vol. 12 (2003): 83–93. Effect of anionic salts on some blood and urine minerals, acid-base balance and udder oedema of dry pregnant cows Susanna Tauriainen Department of Animal Science, PO Box 28, FIN-00014 University of Helsinki, Finland. Current address: Seinäjoki Polytechnic, FIN-60800 Ilmajoki, Finland, e-mail: susanna.tauriainen@seamk.fi Satu Sankari, Satu Pyörälä Department of Clinical Veterinary Sciences, PO Box 57, FIN-00014 University of Helsinki, Finland Liisa Syrjälä-Qvist Department of Animal Science, PO Box 28, FIN-00014 University of Helsinki, Finland The objective of this study was to determine the effect of an anionic diet on mineral metabolism, acid-base status and udder oedema of dairy cows fed grass silage based diets during the dry period. Eighteen pregnant, non-lactating Friesian cows were divided randomly into two groups according to their expected calving date. Dietary cation-anion balance (DCAB), calculated as mill equivalents [(Na+ + K+) – (Cl- + S2-)], for high DCAB (control) and low DCAB treatments were +254 and –41 mEq kg-1 dry matter (DM), respectively. Anionic salts were ammonium chloride (NH 4 Cl), magnesi- um chloride (MgCl 2 ) and magnesium sulphate (MgSO 4 ). Cows received grass silage (5.2 kg DM), hay (0.9 kg DM) and a concentrate mixture (2.7 kg DM) until calving. Blood and urine samples were collected 4, 3, 2 and 1 week before the expected calving date, at calving, 1 day and 1 week after calving. Udder oedema was evaluated by a quantitative and a subjective method. Acidification result- ed in a marked decrease in urinary pH, increased urinary Ca excretion and a change in blood acid- base balance. Blood Ca2+ and plasma Catot concentrations were more stable at parturition for the anionic group, although such differences were not statistically significant. Anionic salts (DCAB –41 mEq kg-1 DM) did not cause udder oedema in experimental cows. Key words: calcium, cows, ion balance, minerals, parturient paresis, udder oedema © Agricultural and Food Science in Finland Manuscript received May 2003 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Vol. 12 (2003): 83–93. Introduction Several studies have demonstrated that feeding anionic salts during the prepartum period can result in a decline in the incidence of milk fever (Block 1984, Oetzel et al. 1988, Joyce et al. 1997). Anionic salts are defined as these con- taining greater amounts of negatively charged fixed anions Cl and S relative to positively mailto:susanna.tauriainen@seamk.fi 84 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Tauriainen, S. et al. Effect of anionic salts on dry cows charged cations Na and K. These ions are im- portant components for determining dietary cat- ion-anion difference (DCAB), calculated as [(Na+ + K+) – (Cl- + S2-)] mEq kg-1 dry matter (DM). In earlier studies we have shown that in- clusion of anionic salts in a concentrate mixture used to supplement grass silage during the dry period has improved dairy cow calcium (Ca) metabolism (Tauriainen et al. 1998abc). How- ever, when potassium (K) concentrations of grass silage exceed 30 g kg-1 DM, it becomes difficult to formulate a palatable diet to recommended DCAB levels. If DCAB remains positive, only negligible effects on Ca metabolism are observed (Tauriainen et al. 1998bc, 2001). Feeding diets of low DCAB can have the dis- advange of increasing the risk of udder oedema. Udder oedema has been reported postpartum when CaCl2 (Lema et al. 1992), NaCl or KHCO3 (Nestor et al. 1988) and NaCl or KCl (Randell et al. 1974) supplements have been fed during the dry period. In contrast, Tucker et al. (1992) reported that low DCAB diets led to a more rap- id regression of udder oedema post partum. How- ever, another study tentatively indicated that low DCAB diets were associated with severe udder oedema, although these findings were not fully documented (Tauriainen et al. 1998a). The objective of this study was to evaluate the effect of anionic salts on mineral metabo- lism and possible occurrence of udder oedema associated with feeding a diet based on concen- trate, grass silage and hay during grazing. Since quantitative measurement of udder oedema was not entirely satisfactory in an earlier study (Tau- riainen et al. 2001), udder oedema was also eval- uated using a visual method. Material and methods Experimental design and treatments Eighteen multiparous Friesian cows (age 49 ± 11 months) were selected from the research herd of the University of Helsinki. Cows weighed 660 ± 52 kg at the beginning of the trial, and were randomly allocated to one of two dietary treat- ments with 9 cows per diet. Cows were fed grass silage (5.2 kg DM d-1), hay (0.9 kg DM d-1) and an experimental concentrate mixture (2.7 kg DM d-1). The experimental feeding period started 4 weeks prior to the expected calving date and ended at parturition. Immediately after calving the cows entered the routine nutrition and man- agement program adopted at the research farm of the University of Helsinki. Experimental diets were assigned as: Diet 1, representing high DCAB (control) and diet 2, representing low DCAB. Cows were divided into two blocks according to age (2nd parity and >2nd parity). Within each block, cows were randomly assigned to one of two treatments in groups ac- cording to the expected calving date. Using the formula (Na+ + K+) – (Cl- + S2-) mEq kg-1 DM, the high DCAB and low DCAB diets contained +254 mEq kg-1 DM and –41 mEq kg-1 DM, re- spectively. The low DCAB diet was formulated according to Tauriainen et al. (2001). Formula- tion of experimental diets and concentrate mix- tures is shown in Table 1, while the chemical composition of experimental diets is presented in Table 2. Cows were housed in a free stall barn. Cows were fed on an individual basis using an elec- tronic transponder (Bio Control A/S, Norway) located on a collar placed around the cow’s neck. Grass silage was offered twice daily (0600 and 1400) and hay and concentrates once daily (1430). In case of refused feed, refusals were weighed and the dry matter content was deter- mined. Samples of grass silage, hay and concen- trate collected each week were pooled; grass si- lage was combined into monthly samples and, hay into bales, and frozen. Grass silage DM was determined weekly by drying at 100°C for 24 h. Cows were weighed and body condition was scored at the beginning of the experiment, two weeks later and after calving. Body condition was assessed on a scale from 1 to 5 where 1 rep- resented extremely thin and 5 represented ex- tremely obese animals (Windman et al. 1982). 85 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Vol. 12 (2003): 83–93. tion of blood gases in whole blood, the remind- er of the sample was used for measurements of ionised Ca and Mg concentrations. Cow body temperature was measured before each blood sampling with a metal thermometer. Urine samples were collected by manual stimulation of the vulva and were frozen prior to pH, creatinine and P determinations. Five ml of urine were transferred into a tube containing 0.5 ml of 12 N HCl and frozen for subsequent of total Ca, Mg, K and Na determinations. Analyses Blood pH, partial pressure of CO2 (pCO2) and acid-base excess were measured using a blood gas analyser (ABL 555 Acid-Base Laboratory, Radiometer A/S, Copenhagen, Denmark). Meas- urements of pH and pCO2 were corrected for Table 1. Formulation of experimental diets on dry matter basis. Concentrate High DCAB Low DCAB Ingredient, % +254 mEq-1 DM –41 mEq-1 DM Oat 32.01 30.81 Wheat-protein 22.30 19.66 Oat bran 10.52 10.80 Barley 19.89 16.34 Wheat molasses 8.12 8.33 CaCO 3 MgPO 4 1.08 1.34 NaCl 1.08 1.11 MgO 0.91 – NH 4 Cl – 3.99 MgCl 2 – 2.10 MgSO 4 – 1.43 Flavour premix 2.71 2.78 Plant oil 0.68 0.58 Selenium mix 0.30 0.31 Vitamin mix 0.20 0.21 Trace element mix 0.20 0.21 Dietary inclusion, % Grass silage 57.67 57.51 Hay 9.79 9.93 Concentrate mixture 32.54 32.56 DCAB = Dietary cation-anion balance Table 2. Dry matter intake (DMI), energy content, chemi- cal composition on a dry matter (DM) basis and cation- anion balance of experimental diets. High DCAB Low DCAB DMI kg d-1 9.19 9.06 ME1)MJ kg-1 DM 9.96 9.70 Crude protein, % 13.29 13.69 Crude fiber, % 23.27 23.00 ADF, % 31.54 22.91 NDF, % 46.07 44.88 Ca, % 0.57 0.57 P, % 0.37 0.37 Mg, % 0.35 0.47 K, % 2.21 2.22 Na, % 0.20 0.20 Cl, % 0.91 1.75 S, % 0.23 0.32 DCAB2)mEq kg-1 DM +254 –41 1) Metabolizable energy calculated according to MAFF (1975). 2) Dietary cation-anion balance calculated as milliequiva- lents (Na+ + K+) – (Cl- + S2-) per kg DM. DCAB = Dietary cation-anion balance ADF = Acid detergent fibre NDF = Neutral detergent fibre Sample collection Blood from jugular vein and urine samples were collected before afternoon feeding, 4, 3, 2, and 1 week prepartum, on the day of calving, and 1 and 7 days postpartum. Two samples were col- lected into 5 ml evacuated heparinized tubes (Venoject VT-050 SHL, Terumo Europe N. V., Leuven, Belgium). The first was centrifuged (1000 g for 8 min) immediately after sampling and the resultant plasma was stored frozen (–20°C) for Na+, K+, Cl-, total Ca, Mg, P and creatinine determinations. The second was stored frozen (–20°C) for haemoglobin measurements. An additional sample was collected into a 2-ml syringe containing Ca-stabilised heparin (Pico 50, Radiometer Copenhagen) for measurements of acid-base status. Syringes were placed on ice after sampling. After an immediate determina- 86 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Tauriainen, S. et al. Effect of anionic salts on dry cows measured body temperature for each cow accord- ing to the manufacturer instructions. Corrected pH and pCO2 values were subsequently used to calculate true bicarbonate (aHCO3) and base ex- cess (BE) values. Plasma and urinary Ca and Mg concentrations were assessed by an atomic ab- sorption spectrophotometer (Model 2380, Per- kin Elmer Corp., Norwalk, Conn., USA), and creatinine concentrations were determined using an automated kinetic alkaline picrate method (Fabiny and Ertigshausen 1971). Inorganic phos- phorus in plasma was determined based on the colorimetric method of Daly and Ertigshausen (1972). Concentrations of Na+, K+ and Cl- in plas- ma (KONE Microlyte 3 + 2, KONE Corp., Es- poo, Finland) and ionised Ca and Mg in whole blood (Microlyte 6 Ion Selective Analyser, Kone- lab Corp., Espoo, Finland) were analysed using ion-specific electrodes. Concentrations of Na and K in urine were determined using a flame photometer (Corning 480, Ciba Corning Diagnostics Limited, Hal- stead, UK). Urinary pH was measured with a pH meter (Radiometer Copenhagen, PHM 83 Autocal pH meter). Fractional excretion (FEx) of electrolytes (x) was calculated as: FEx, % = xu × creatininep/xp × creatinineu × 100; where u refers to urinary electrolyte concentration, and p to the corresponding concentration in plas- ma. The Cl content of the grass silage was de- termined according to AOAC (1984). Chemi- cal composition of feeds was measured accord- ing to previously reported methods (Tauriai- nen et al. 1998a). Udder oedema was evaluated by measuring the vertical height from the hind udder attach- ment to the root of the hind teat and the horizon- tal width from the outer edge of the udder to medial ligament and marking a cross at the in- tersection of these lines. Measurements were performed from the centre of the cross to the medial ligament and the root of rear teat of each side of the udder (Fig. 1). Evaluation was done two weeks from beginning of the experiment, at parturition, 1 and 2 weeks postpartum. The vis- ual and manual evaluation of udder oedema was modified according to the 5-point system of Nestor et al. (1988). The scoring system was (Fig. 2): 1, no oedema; 2, slight oedema, defined as oedema in the base of the udder that had spread to one or more quarters, but not yet to- wards the navel; 3, moderate oedema, defined the conditions for 2, in addition to the appear- ance oedematous fluid in the navel and midline, but not yet spread upward in the rear of the ud- der; 4, marked oedema; oedema present in the entire udder; 5, marked and widespread, oede- ma being visible in the brisket moving upwards approaching the vulva. Statistical analysis Experimental data was analysed in two parts; prepartum from weeks 4 to 1 pre calving and peripartum from 1 week before the expected calving to 1 week after calving. Plasma and uri- A B C Fig. 1. The quantitative measure- ment method of udder oedema. A = Drawing the halfpoint of the udder in the vertical level. B = Drawing the halfpoint of the ud- der in the horizontal level. C = The proper measurement method of udder oedema: the measurement of vertical length and horizontal width. (Drawing: Susanna Tau- riainen). 87 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Vol. 12 (2003): 83–93. Fig. 2. Udder oedema scores (1 to 5). Hatched areas represent locations of oedema. (Drawing: Susanna Tauriainen). nary data was analysed by repeated measures analysis of variance using the SAS (1985) gen- eral linear model procedure for a complete block design that included the effects of treatment, age and their interactions. Residuals of all data with- in dietary treatments were assessed for normali- ty (Shapiro-Wilk test). A one-way analysis of variance of the two treatment groups was per- formed for data collected at 4 weeks precalving to assess initial differences between experimen- tal groups. Due to significant differences be- tween cows at the start of the trial in Ca/creati- nine and K/creatinine, pre-treatment values were used as covariates. Data concerning udder oede- ma was analysed on a week by week basis using least squares analysis of variance, following the general linear models procedure. The statistical model included treatment, age and their interac- tion. For all statistical analysis, significance was declared at P < 0.05. Results Palatability of the experimental concentrate was good with no refusals. Mean body condition was 3.2 at the beginning of the trial and 3.1 at partu- rition. The daily portion of chloride- and sulphate salts in the concentrate mixture during the dry period did not significantly increase udder oede- ma during the period between 2 weeks before and 2 weeks post calving based on visual meas- urements of udder oedema. The cows entering 3rd or greater loctation had more udder oedema 2 weeks postpartum (Fig. 3). For quantitative measurements, estimates of changes of horizon- tal width and vertical height were evaluated on a weekly basis to exclude a mutual correlation between age and udder size. Feeding had no ef- fect on udder oedema (Fig. 4 and Table 3). Two cows from the cationic group had signs 88 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Tauriainen, S. et al. Effect of anionic salts on dry cows of clinical milk fever. The first case occurred at parturition and the cow received a calcium infu- sion after blood sampling (Ca2+ < 0.88 mmol l-1). The second case was noticed one week after parturition, and the cow was treated over two successive days following blood sampling (Ca2+ < 0.81 mmol l-1 and 0.70 mmol l-1, respectively). Plasma Cl concentration was significantly high- er for cows fed the low DCAB compared to the high DCAB diet cows (Table 4). A low DCAB had no effects on other blood mineral parame- ters. Older multiparous cows had significantly (P < 0.05) higher blood Mg2+ concentration pre- partum and significantly lower plasma P concen- tration peripartum than cows at their second calv- ing. A lowered DCAB tended to decrease blood pH (P = 0.057) and significantly decreased (P < 0.05) blood HCO3 and actual base excess (aBE) (P < 0.05) prepartum (Table 5). Treat- ments and age had no effect on pCO2 during the trial. Urinary Ca excretion was significantly high- er (P < 0.001) and urinary pH markedly lower (P < 0.001) in cows fed the low DCAB diet (Table 6). Neither urinary excretion of Mg, K, and Na, nor urine FE% of Mg, K, Na or P were significantly influenced by experimental treat- ments. Fig. 3. Mean udder oedema of experimental cows with the 2nd calving and cows with more than two calving using the subjective evaluation method. Table 3. Mean vertical height and horizontal width of udder (cm) fed diets with different dietary cation-anion balance (DCAB). Time from parturition Factor –2 wk 0 wk +1 wk +2 wk Vertical height of udder, cm High DCAB 24.4 32.4 32.1 31.7 Low DCAB 27.7 32.6 30.5 30.4 SEM 1.24 0.92 1.12 0.97 P-value ns ns ns ns Horizontal width of udder, cm High DCAB 4.3 8.1 6.3 6.5 Low DCAB 4.6 7.9 6.5 5.8 SEM 0.30 0.63 0.55 0.59 P-value ns ns ns ns ns = non-significant SEM = standard error of means 89 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Vol. 12 (2003): 83–93. Fig. 4. Mean udder oedema of ex- perimental cows fed different cat- ion-anion balance (DCAB) using the subjective evaluation method. Table 4. Mean plasma mineral concentrations of dry cows fed diets with different dietary cation-anion balance (DCAB). Time from parturition Significance Factor –4 wk –3 wk –2 wk –1 wk 0 +1 d +1 wk Prepartum Peripartum Calcium2+ High DCAB 1.31 1.32 1.32 1.31 1.11 1.19 1.21 mmol l-1 Low DCAB 1.34 1.32 1.34 1.32 1.24 1.18 1.30 SEM 0.018 0.011 0.014 0.015 0.035 0.049 0.054 ns ns Calciumtot High DCAB 2.46 2.47 2.46 2.47 1.94 2.16 2.21 mmol l-1 Low DCAB 2.51 2.37 2.43 2.37 2.29 2.18 2.39 SEM 0.062 0.023 0.023 0.034 0.077 0.086 0.086 ns ns Magnesiumtot High DCAB 0.98 0.97 0.91 0.94 1.11 1.00 1.07 mmol l-1 Low DCAB 0.94 0.99 1.03 0.94 1.07 1.06 0.96 SEM 0.033 0.023 0.029 0.031 0.058 0.043 0.052 ns ns Chloride High DCAB 101.5 101.8 101.9 102.9 105.4 103.9 100.3 mmol l-1 Low DCAB 102.1 103.3 104.2 104.5 106.4 103.7 98.7 SEM 0.60 0.76 0.72 0.58 0.89 0.89 0.72 * ns P < 0.05 *, ns = non-significant SEM = standard error of means Table 5. Mean blood acid base balance of dry cows fed diets with different dietary cation-anion balance (DCAB). Time from parturition Significance Factor –4 wk –3 wk –2 wk –1 wk 0 +1 d +1 wk Prepartum Peripartum Blood pH High DCAB 7.38 7.39 7.39 7.39 7.37 7.38 7.38 Low DCAB 7.37 7.36 7.37 7.38 7.37 7.37 7.38 SEM 0.008 0.011 0.011 0.006 0.013 0.011 0.008 ns ns Blood HCO 3 High DCAB 27.1 27.3 27.7 27.5 25.6 26.3 25.5 mmol l-1 Low DCAB 26.9 25.3 24.9 25.3 25.6 27.5 28.2 SEM 0.62 0.65 0.74 0.77 1.10 1.15 0.73 * ns Blood aBE High DCAB 2.36 2.65 3.21 2.94 0.93 1.59 1.00 mmol l-1 Low DCAB 2.05 0.42 0.42 1.10 1.05 2.61 3.58 SEM 0.587 0.594 0.769 0.732 1.132 1.110 0.729 * ns P < 0.05 *, ns = non-significant SEM = standard error of means aBE = actual base excess. 90 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Tauriainen, S. et al. Effect of anionic salts on dry cows Discussion The incidence of udder oedema was similar in the anionic group compared to control group. This indicated that daily supplements of anionic salts (3.2 Eq) during the dry period did not in- crease the risk of udder oedema peripartum. High intakes of sodium chloride (Randell et al. 1974, Jones et al. 1984, Nestor et al. 1988), potassium (Sanders and Sanders 1981) or a high ratio of potassium to calcium and magnesium have been shown to cause udder oedema peripartum (San- ders and Sanders 1982). In the current study so- dium intake was 16 g per day, which approached published requirements of 12 g per day (Tuori et al. 2001). Furthermore, the K/(Ca + Mg) -ra- tio could be maintained below a recommended level of 2.2 (Kemp and t’Hart 1957), despite a relatively high dietary K concentration (2.2% of DM). In an earlier study (Tauriainen et al. 2001) dietary K content of 3.4% of DM was found to have no influence on the incidence of udder oede- ma, when the dietary K/(Ca + Mg) -ratio was low (1.1). Intake of Cl should be prevented from exceeding 195 g d-1 to avoid the risk of udder oedema (Jones et al. 1984), as was the case in the present study (153 g d-1). On the basis of the current study a visual method for the evaluation of udder oedema was more reliable than quantitative measurements, since the latter accounted for oedema spreading to the hind quarters, but not that towards the na- vel. In addition, the quantitative measurement of udder oedema is more time consuming. It ap- pears that a subjective oedema rating system using a 10-point scale is a useful tool to accu- rately assess the severity of udder oedema in dairy cattle (Tucker et al. 1992). The low DCAB diet resulted in higher ion- ised Ca at parturition relative to the high DCAB, although these differences were not significant- ly different. This finding tends to suggest a ben- eficial effect of anionic salts on calcium metab- olism. However, the proportion of total blood Ca in ionised form was significantly higher in the low DCAB group (55.5%) prepartum compared to the high DCAB group (53.4%). In healthy cows the concentration of ionised Ca is highly correlated with the concentration of the total Ca, since concentrations of albumin, bicarbonate, phosphate, citrate and lactate are relatively con- stant (Lincoln and Lane 1990, Riond et al. 1995). However, the concentration of total Ca is not directly related in cows with abnormal Ca status (Kvart et al. 1982), such that the correlation be- Table 6. Mean urinary pH and calcium excretion of dry cows fed diets with different dietary cation-anion balance (DCAB). Time from parturition Significance Factor –4 wk –3 wk –2 wk –1 wk 0 +1 d +1 wk Prepartum Peripartum pH in urine High DCAB 8.25 8.31 8.28 8.34 8.04 8.20 7.71 Low DCAB 8.24 6.43 7.22 7.39 6.82 8.01 8.05 SEM 0.178 0.237 0.205 0.213 0.202 0.117 0.200 *** ** Ca/creat.1) High DCAB 0.20 0.40 0.36 0.18 0.01 0.06 0.42 Low DCAB 0.20 1.01 0.75 0.68 0.34 0.04 0.56 SEM 0.000 0.087 0.141 0.095 0.085 0.044 0.144 *** * Ca FE%2) High DCAB 0.86 1.68 1.76 0.87 0.16 0.33 1.99 Low DCAB 0.86 4.37 3.23 3.36 1.75 0.16 2.34 SEM 0.000 0.402 0.631 0.502 0.476 0.204 0.591 *** P < 0.05 *, P < 0.01 **, P < 0.001 *** SEM = standard error of the means 1) mmol/mmol 2) fractional excretion 91 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Vol. 12 (2003): 83–93. tween ionised and total Ca can change during milk fever (Carlström 1970). In the current study, increases in the proportion of ionised Ca in total blood Ca concentrations for the anionic group may be due to changes in blood acid-base bal- ance. A decrease in blood pH shifts the equilib- rium between ionised Ca and protein-bound Ca causing an increase in ionised Ca concentrations. Furthermore, protein binding of ionised Ca is dependent on hydrogen ion concentration (Thode et al. 1983, Szenci et al. 1988). A marked decrease in urinary pH and increase in urinary Ca excretion was observed for cows fed anionic salts, indicating that acidification was successful. A decrease in blood pH, HCO3 con- centration and actual base excess (aBE) was ob- served in the anionic group one week after the start of the experiment. However, acidification of the diet was not excessive since cows rapidly compensated for the acid load and achieved acid- base balance at parturition. The results indicate that despite the high K content of grass silage (31 g K kg-1 DM) it was possible to influence Ca metabolism of the dry cow. In addition the pal- atability of the concentrate mixture was good, even though anionic salts were applied at maxi- mum recommended levels (3.2 Eq d-1). In rumi- nants, the maximum tolerable level for dietary S is 0.4% of DM, after which additional sulphur intake can decrease voluntary feed intake and induce toxicity. The maximum tolerance of die- tary Cl, when fed in the form of NaCl, has been reported to be 9.0% for cattle and sheep (NRC 1980). In an earlier study (Tauriainen et al. 1998c) low plasma Mg concentrations (<0.85 mmol l-1) at parturition were observed for some cows fed 17 g Mg per day. In the current study none of the cows were hypomagnesaemic at parturition indicating that it was beneficial to provide addi- tional Mg (37 g Mg d-1) above the current rec- ommendations in Finland (17 g Mg d-1). Blood ionised Mg was significantly higher (P < 0.05) prepartum and plasma inorganic P significantly (P < 0.05) lower peripartum in multiparous cows than for cows at their second calving. Plasma Mg or inorganic P was not affected by DCAB, a finding in agreement with previous studies (Tucker et al. 1992, Joyce et al. 1997). General- ly moderate hypophosphataemia and hypermag- nesaemia are accompanied by a reduction in plas- ma Ca at parturition, suggesting that changes in P and Mg metabolism are related to hypocalsae- mia rather than to the feeding of an acidic diet (Phillippo et al. 1994). However, the increase in plasma Cl concentration observed for the anion- ic group, can be attributed to supplements of chloride salt. The results from the current study showed that 3.2 Eq of chloride- and sulphate salts in daily portion of –40 mEq kg-1 DM of DCAB could be used for the feeding of dry cows without increas- ing the risk of udder oedema. A clear increase in urinary Ca excretion and decrease in urinary pH were seen despite a high K content of grass si- lage (31 g K kg-1 DM). However, the amount of anionic salts currently offered represented the upper recommended limits, such that under prac- tical conditions it is uncertain whether milk fe- ver can be prevented in cows fed grass silage with a K content above 31 g K kg-1 DM. Acknowledgements. The authors appreciate the technical assistance of Sakari Alasuutari, Riikka Rinne, Carolina Sjögård and Jari Hiljanen. The co-operation of Merja Hol- ma is also gratefully acknowledged. This study was finan- cially supported by Rehuraisio Ltd, the A. Kordelin foun- dation, the Oiva Kuusisto foundation and Seinäjoki Poly- technic. References Block, E. 1984. Manipulating dietary anions and cations for cows to reduce incidence of milk fever. Journal of Dairy Science 67: 2939–2948. Carlström, G. 1970. Studies on parturient paresis in dairy cows. V. On the composition and calcium binding capacity of two bovine serum protein fractions, with 92 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Tauriainen, S. et al. Effect of anionic salts on dry cows special regard to parturient paresis. Acta Veterinaria Scandinavica 11: 89–102. Jones, T.O., Knight, R. & Evans, R.K. 1984. Chronic ud- der oedema in milking cows and heifers. Veterinary Record 115: 218–219. Joyce, P.W., Sanchez, W.K. & Goff, J.P. 1997. Effect of anionic salts in prepartum diets based on alfalfa. Journal of Dairy Science 80: 2866–2875. Kemp, A. & t’Hart, M.L. 1957. Grass tetany in grazing milking cows. Netherlands Journal of Agricultural Science 5, 4: 4–16. (ref. Sanders, D.E. & Sanders, J.A. 1982) Kvart, C., Björsell, K.A. & Larssen, L. 1982. Parturient paresis in the cow. Serum ionized calcium concen- trations before and after treatment with different cal- cium solutions – classification of different degrees of hypo- and hypercalcemia. Acta Veterinaria Scandi- navica 23: 184–196. Lema, M., Tucker, W.B., Aslam, M., Shin, I.S., Le Ruyet, P. & Adams, G.D. 1992. Influence of calcium chlo- ride fed prepartum on severity of edema and lacta- tional performance of dairy heifers. Journal of Dairy Science 75: 2388–2393. Lincoln, S.D. & Lane, V.M. 1990. Serum ionized calcium concentration in clinically normal dairy cattle, and changes associated with calcium abnormalities. Jour- nal of the American Veterinary Medical Association 197, 11: 1471–1474. Nestor, K.E., Jr., Hemken, R.W. & Harmon, R.J. 1988. Influence of sodium chloride and potassium bicarbo- nate on udder edema and selected blood parame- ters. Journal of Dairy Science 71: 366–372. NRC 1980. Mineral tolerance of domestic animals. Na- tional Research Council. Subcommittee on Mineral Toxicity in Animals. National Academy Press. Wash- ishington, D.C. USA. 577 p. Oetzel, G.R., Olson, J.D., Curtis, C.R. & Fettman, M.J. 1988. Ammonium chloride and ammonium sulfate for prevention of parturient paresis in dairy cows. Jour- nal of Dairy Science 71: 3302–3309. Phillippo, M., Reid, G.W. & Nevison, I.M. 1994. Parturi- ent hypocalcaemia in dairy cows: effects of dietary acidity on plasma minerals and calciotrophic hor- mones. Research in Veterinary Science 56: 303–309. Randell, W.E., Hemken, R.W., Bull, L.S., Douglas, L.W. 1974. Effect of dietary sodium and potassium on ud- der edema in Holstein heifers. Journal of Dairy Sci- ence 57: 472–475. Riond, J.L., Kocabagli, N., Spichiger, U.E. & Wanner, M. 1995. The concentration of ionized magnesium in serum during the periparturient period of non-paretic dairy cows. Veterinary Research Communications 19: 195–203. Sanders, D.E. & Sanders, J.A. 1981. Chronic udder ede- ma in dairy cows. Journal of the American Veteri- nary Medical Association 178: 1273–1274. Sanders, D.E. & Sanders, J.A. 1982. Potassium and ud- der edema. Journal of the American Veterinary Med- ical Association 181: 324. SAS 1985. SAS User’s Guide, Statistics. 5th Edition SAS Institute Inc. Cary, NC. Szenci, O., Felkai, F., Märcz, I. & Takacs, E. 1988. Ion- ized calcium, total calcium and acid-base values of blood in healthy and acidotic dogs. Journal of Veter- inary Medical A 35: 125–128. Tauriainen, S., Sankari, S., Pyörälä, S. & Syrjälä-Qvist, L. 1998a. Effect of anionic salts in concentrate mix- ture and calcium intake on some blood and urine minerals, acid-base balance and feed intake of dry pregnant cows on grass silage based feeding. Agri- cultural and Food Science in Finland 7: 523–533. Tauriainen, S., Sankari, S., Pyörälä, S. & Syrjälä-Qvist, L. 1998b. Effect of anionic salts in concentrate mix- ture and magnesium intake on some blood and urine minerals, acid-base balance and feed intake of dry pregnant cows on grass silage based feeding. Agri- cultural and Food Science in Finland 7: 535–543. Tauriainen, S., Sankari, S. & Syrjälä-Qvist, L. 1998c. Ef- fect of anionic salts in concentrate mixture on some blood and urine minerals, acid-base balance and feed intake of dry pregnant cows on grass silage based feeding with high calcium intake. Agricultural and Food Science in Finland 7: 545–552. Tauriainen, S., Sankari, S., Pyörälä, S. & Syrjälä-Qvist, L. 2001. Effect of anionic salts and potassium intake on some blood and urine minerals and acid-base balance of dry pregnant cows on grass silage based feeding. Journal of Animal and Feed Science 10: 57– 71. Thode, J., Fogh-Andersen, N., Wimberley, P.D., Moller Sorensen, A. & Siggaard-Andersen, O. 1983. Rela- tion between pH and ionized calcium in vitro and in vivo in man. Scandinavian Journal of Clinical and Laboratory Investigation 43: 79–80 (Suppl. 165). Tucker, W.B., Hogue, J.F., Adams, G.H., Aslam, M., Shin, I.S. & Morgan, G. 1992. Influence of dietary cation- anion balance during the dry period on the occur- rence of parturient paresis in cows fed excess calci- um. Journal of Animal Science 70: 1238–1250. Tuori, M., Kaustell, K., Valaja, J., Aimonen, E., Saari- salo, E. & Huhtanen, P. 2000. Rehutaulukot ja ruokin- tasuositukset. Helsinki, 99 p. 93 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Vol. 12 (2003): 83–93. SELOSTUS Anionisten suolojen vaikutus ummessa olevien lehmien veren ja virtsan kivennäisiin, happo-emästasapainoon sekä utarepöhöön Susanna Tauriainen, Satu Sankari, Satu Pyörälä ja Liisa Syrjälä-Qvist Helsingin yliopisto Kokeen tarkoituksena oli selvittää anionisten suolo- jen vaikutuksia ummessa olevien lehmien veren ja virtsan kivennäisaineenvaihduntaan, happo-emästasa- painoon sekä erityisesti utarepöhöön. Kationi-anioni -tasapaino laskettiin [(Na+ + K+) – (Cl- + S2-)] mEq/kg kuiva-ainetta (ka), ja se oli joko +254 tai –41 mEq/kg ka. Lehmät saivat säilörehua 5,2 kg ka, heinää 0,9 kg ka ja täysrehua 2,7 kg ka nel- jä viikkoa ennen odotettua poikimista poikimispäi- vään saakka. Veri- ja virtsanäytteet otettiin 4, 3, 2 ja 1 viikkoa ennen odotettua poikimista sekä poikimis- päivänä, 1 vrk ja 1 viikko poikimisen jälkeen. Utare- pöhö mitattiin ja arvioitiin silmämääräisesti. Anioniset suolat alensivat virtsan pH:ta, lisäsivät kalsiumin erittymistä virtsaan ja muuttivat veren hap- po-emästasapainoa. Veren ionisoitunut kalsiumpitoi- suus ja plasman kalsiumpitoisuus pysyivät anionisia suoloja saaneilla lehmillä poikimisen aikaan vakaam- pina kuin lehmillä, jotka eivät olleet saaneet ani- onisia suoloja. Anionisten suolojen syöttäminen (–40 mEq/kg ka) ennen poikimista ei aiheuttanut leh- mille utarepöhöä. 94 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Tauriainen, S. et al. Effect of anionic salts on dry cows Title Introduction Material and methods Results Discussion References SELOSTUS