Chemical Composition of Irish Forages
Grass, Silage & Hay

Introduction
The following is a summary of the typical levels of Major- and Trace- Elements in Irish forages, based on samples analysed over a 4-year period in Johnstown Castle, Wexford.

The following were omitted from the original Johnstown data: DM <10% (6 grasses/silages); Ca <.10% DM (2 grasses) or >2.00% DM (2 grasses, 4 silages); K <.50% DM (4 grasses); Mg >.50% DM (2 grasses); Na <.03% DM (2 grasses, 1 silage) or >1.40% DM (1 grass, 5 silages); S <.05% DM (2 grasses) or >1.00% DM (1 grass).

Trace Element data excluded (because of experimental, slurry or soil contamination) were: Cu: 12 grasses >25 ppm DM; 6 silages >40 ppm DM; Mo: 1=400; 1 = 88; Se: 5 =>4; 2 = 4-84; I : 22 = >1; 14 = >1; Zn: 7 = >100; 19 = >100; Mn: 8 = 708-980; Co: 8 = >.39; 2 = >.39 
Summary & Conclusions
  1. Multiple imbalances: Irish forages (grass, grass silage and hay) have multiple imbalances of Major- and Trace- Elements. Routine mineral supplementation of Irish cattle and sheep (young-, growing-, adult-, breeding- and lactating stock) is sound national policy, both indoors and at pasture. The most important minerals for routine supplementation are Cu, Se, I and Co, but it is advisable to include a proper balance of the other Major- and Trace- Elements in vitamin-mineral supplements also.
  2. Grass has a poor balance of Major Elements (high N, K, S, and many low Mg and Na values) (Table 1a, Table 2a). It also has multiple deficiencies of Trace Elements (Cu, Se, I and, sometimes, Co values) and many high Mo levels (Table 1b, Table 2b).
  3. At pasture, routine supplementation of susceptible stock (lactating cows and ewes) with Mg is advisable during periods of tetany-risk. Routine supplementation with Trace Elements is also advisable. In particular, a generous I-supply is advisable during the breeding season, as blood I-values (plasma inorganic iodine) fall within days of withdrawal of I-supplement.
  4. Farmers should avoid unnecessary use of N, P, K and S fertilisers, as high levels of these Elements in grass can compromise the absorption of Mg and Trace Elements. If they must apply lime to improve their swards, they should also take great care to provide generous supplements of Cu, Co, I and Zn to their cattle and sheep. (See note on Cu for sheep, below).
  5. Hay is very deficient in N (protein), P and Mg (Table 5a, Table 6a). Many samples are also low in Ca and Na. It is also very deficient in Cu, I, Se, Zn and of unknown Co status (Table 5b, Table 6b). High-producing animals fed a lot of hay (or straw) in winter should receive additional protein, Trace Elements, P, Mg and vitamin A, D3 and E supplements.
  6. Grass silage has a Major Element composition somewhere between that of grass and hay (Table 3a, Table 4a). It is often low in Mg, N (protein) and P and often needs supplements of those Elements, plus protein. It has Trace Element levels somewhere between those of grass and hay (Table 3b, Table 4b). Its levels of Se and I are often too low for dairy cows. Ruminants should receive routine supplementation with those minerals (plus Cu and vitamins A, D3 and E) when fed silage in winter.
  7. Cu-poisoning in sheep: Sheep are very susceptible to Cu-poisoning. They should not receive Cu supplements except on veterinary advice. If needed, slow-release forms of copper (i.e. Cu-oxide capsules) are the safer than other forms of Cu-supplements for sheep.
Table 1a. DM (%), Ca, P, K, Mg, N, Na, S levels (% DM) in IRISH GRASS
year 90 - N
DM: -
Ca: 468
P: 472
K: 452
Mg: 471
N: 458
Na: 450
S: 350
year 90 - sd
DM: -
Ca: .156
P: .078
K: .710
Mg: .047
N: .873
Na: .17
S: .104
year 90 - se
DM: -
Ca: .007
P: .004
K: .033
Mg: .002
N: .041
Na: .008
S: .006
year 90 - x
DM: -
Ca: .636
P: .407
K: 2.869
Mg: .209
N: 3.660
Na: .309
S: .367
year 91 - n
DM: 7
Ca: 721
P: 731
K: 723
Mg: 723
N: 730
Na: 725
S: 662
year 91 - sd
DM: 4.76
Ca: .178
P: .085
K: .759
Mg: .045
N: .896
Na: .181
S: .100
year 91 - se
DM: 1.79
Ca: .007
P: .003
K: .028
Mg: .002
N: .033
Na: .007
S: .004
year 91 - x
DM: 20.26
Ca: .655
P: .399
K: 2.788
Mg: .204
N: 3.605
Na: .297
S: .403
year 92 - n
DM: 7
Ca: 634
P: 632
K: 631
Mg: 634
N: 630
Na: 610
S: 594
year 92 - sd
DM: 6.98
Ca: .190
P: .103
K: .798
Mg: .042
N: 1.04
Na: .151
S: .081
year 92 - se
DM: 2.64
Ca: .008
P: .004
K: .032
Mg: .002
N: .041
Na: .006
S: .003
year 92 - x
DM: 19.23
Ca: .640
P: .392
K: 2.835
Mg: .195
N: 3.263
Na: .263
S: .381
year 93 - n
DM: 10
Ca: 51
P: 51
K: 51
Mg: 51
N: 52
Na: 51
S: 50
year 93 - sd
DM: 2.02
Ca: .272
P: .103
K: .785
Mg: .039
N: .917
Na: .210
S: .072
year 93 - se
DM: .64
Ca: .038
P: .014
K: .11
Mg: .006
N: .127
Na: .029
S: .010
year 93 - x
DM: 21.14
Ca: .650
P: .446
K: 2.983
Mg: .181
N: 3.750
Na: .281
S: .388
all - max
DM: 29.0
Ca: 1.80
P: 1.27
K: 6.60
Mg: .44
N: 6.27
Na: 1.25
S: .82
all - min
DM: 11.6
Ca: .14
P: .08
K: .51
Mg: .08
N: .86
Na: .03
S: .06
all - n
DM: 24
Ca: 1874
P: 1886
K: 1857
Mg: 1879
N: 1870
Na: 1836
S: 1656
all - sd
DM: 4.8
Ca: .181
P: .091
K: .763
Mg: .045
N: .957
Na: .171
S: .095
all - se
DM: .98
Ca: .004
P: .002
K: .018
Mg: .001
N: .022
Na: .004
S: .002
all - x
DM: 20.25
Ca: .645
P: .400
K: 2.829
Mg: .202
N: 3.507
Na: .288
S: .387
Table 1b. Cu, Mo, Se, I, Zn, Mn, Co levels (mg/kg DM) in IRISH GRASS
year 90 - N
Cu: 400
Mo: 362
Se: 319
I: 240
Zn: 136
Mn: 464
Co: 1
year 90 - sd
Cu: 2.787
Mo: 2.582
Se: .224
I: .168
Zn: 8.807
Mn: 67.68
Co: -
year 90 - se
Cu: .139
Mo: .136
Se: .013
I: .011
Zn: .755
Mn: 3.14
Co: -
year 90 - x
Cu: 9.686
Mo: 2.045
Se: .113
I: .224
Zn: 31.007
Mn: 98.08
Co: .060
year 91 - n
Cu: 691
Mo: 661
Se: 551
I: 460
Zn: 147
Mn: 712
Co: -
year 91 - sd
Cu: 2.497
Mo: 2.905
Se: .141
I: .172
Zn: 9.227
Mn: 115.780
Co: -
year 91 - se
Cu: .095
Mo: .113
Se: .006
I: .008
Zn: .761
Mn: 4.34
Co: -
year 91 - x
Cu: 9.127
Mo: 2.437
Se: .083
I: .27
Zn: 31.41
Mn: 138.6
Co: -
year 92 - n
Cu: 590
Mo: 577
Se: 531
I: 73
Zn: 585
Mn: 639
Co: 7
year 92 - sd
Cu: 2.728
Mo: 3.582
Se: .1
I: .238
Zn: 8.22
Mn: 88.87
Co: -
year 92 - se
Cu: .360
Mo: .303
Se: .019
I: .067
Zn: 1.40
Mn: 11.61
Co: -
year 92 - x
Cu: 8.692
Mo: 3.488
Se: .093
I: .378
Zn: 31.927
Mn: 100.45
Co: .140
year 93 - n
Cu: 60
Mo: 58
Se: 58
I: 4
Zn: 60
Mn: 53
Co: 1
year 93 - sd
Cu: 2.791
Mo: 2.306
Se: .143
I: .134
Zn: 10.84
Mn: 84.52
Co: -
year 93 - se
Cu: .360
Mo: .303
Se: .019
I: ..067
Zn: 1.40
Mn: 11.61
Co: -
year 93 - x
Cu: 8.692
Mo: 3.488
Se: .093
I: .378
Zn: 31.927
Mn: 100.45
Co: .140
all - max
Cu: 23.7
Mo: 52.0
Se: 2.50
I: 1.00
Zn: 84
Mn: 693
Co: .28
all - min
Cu: 1.6
Mo: .1
Se: .01
I: .05
Zn: 13
Mn: 10
Co: .06
all - n
Cu: 1741
Mo: 1658
Se: 1459
I: 777
Zn: 928
Mn: 1872
Co: 9
all - sd
Cu: 2.666
Mo: 3.092
Se: .15
I: .182
Zn: 8.673
Mn: 97.02
Co: -
all - se
Cu: .064
Mo: .076
Se: .004
I: .007
Zn: .285
Mn: 2.24
Co: -
all - x
Cu: 9.217
Mo: 2.492
Se: .093
I: .261
Zn: 30.83
Mn: 119.82
Co: .156
Table 2a. Major Element Assessment in IRISH GRASS: % Samples in each category (see Assessment Criteria) in relation to dairy cow requirement
ca
Very low: .7
Low: 7.8
Normal: 90.2
High: 1.3
dm
Very low: 22.7
Low: 22.7
Normal: 27.3
High: 27.3
k
Very low: -
Low: 0
Normal: 68.4
High: 31.6
mg
Very low: 6.9
Low: 42.2
Normal: 49.8
High: 1.1
n
Very low: .4
Low: 17.2
Normal: 17.3
High: 65.1
na
Very low: 6.9
Low: 12.2
Normal: 77.1
High: 3.8
p
Very low: .7
Low: 31.2
Normal: 63.9
High: 4.2
s
Very low: .3
Low: 1.0
Normal: 18.2
High: 80.5
Table 2b. Trace Element Assessment in IRISH GRASS: % Samples in each category (see Assessment Criteria) in relation to dairy cow requirement
co
Very low: -
Low: 11.1
Normal: 89.9
High: 0
cu
Very low: 3.4
Low: 62.0
Normal: 34.6
High: 0
i
Very low: 46.6
Low: (38.1 12.4)
Normal: 2.9
High: 0
mn
Very low: .7
Low: 1.5
Normal: (8.8 80.9)
High: 8.1
mo
Very low: -
Low: -
Normal: 57.9
High: (32.0 7.8 2.3)
se
Very low: 71.9
Low: (18.7 3.7)
Normal: 4.5
High: 1.2
zn
Very low: 3.1
Low: 21.4
Normal: (64.2 11.3)
High: 0
Table 3a. DM (%), Ca, P, K, Mg, N, Na, S levels (% DM) in IRISH SILAGE
year 90 - N
DM: -
Ca: 403
P: 404
K: 400
Mg: 405
N: 397
Na: 399
S: 383
year 90 - sd
DM: -
Ca: .145
P: .066
K: .618
Mg: .048
N: .686
Na: .168
S: .111
year 90 - se
DM: -
Ca: .007
P: .003
K: .031
Mg: .002
N: .034
Na: .008
S: .006
year 90 - x
DM: -
Ca: .660
P: .335
K: 2.405
Mg: .193
N: 2.618
Na: .364
S: .296
year 91 - n
DM: 5
Ca: 661
P: 659
K: 657
Mg: 658
N: 655
Na: 655
S: 625
year 91 - sd
DM: 8.25
Ca: .17
P: .068
K: .633
Mg: .04
N: .475
Na: .153
S: .100
year 91 - se
DM: 3.69
Ca: .007
P: .003
K: .025
Mg: .002
N: .019
Na: .006
S: .004
year 91 - x
DM: 24.60
Ca: .738
P: .299
K: 2.404
Mg: .178
N: 2.423
Na: .371
S: .312
year 92 - n
DM: 2
Ca: 531
P: 536
K: 534
Mg: 535
N: 534
Na: 535
S: 528
year 92 - sd
DM: 1.20
Ca: .144
P: .065
K: .601
Mg: .043
N: .479
Na: .145
S: .106
year 92 - se
DM: .85
Ca: .006
P: .003
K: .026
Mg: .002
N: .021
Na: .006
S: .005
year 92 - x
DM: 19.60
Ca: .667
P: .312
K: 2.260
Mg: .186
N: 2.243
Na: .351
S: .328
year 93 - n
DM: -
Ca: 45
P: 45
K: 45
Mg: 45
N: 45
Na: 45
S: 39
year 93 - sd
DM: -
Ca: .117
P: .055
K: .483
Mg: .035
N: .582
Na: .122
S: .100
year 93 - se
DM: -
Ca: .017
P: .008
K: .072
Mg: .005
N: .087
Na: .018
S: .016
year 93 - x
DM: -
Ca: .629
P: .229
K: 2.243
Mg: .178
N: 2.178
Na: .314
S: .284
all - max
DM: 41.0
Ca: 1.61
P: .72
K: 5.59
Mg: .43
N: 5.86
Na: 1.03
S: .98
all - min
DM: 18.4
Ca: .25
P: .10
K: .63
Mg: .08
N: .89
Na: .04
S: .08
all - n
DM: 7
Ca: 1640
P: 1644
K: 1636
Mg: 1643
N: 1631
Na: 1634
S: 1575
all - sd
DM: 7.36
Ca: .159
P: .068
K: .619
Mg: .043
N: .557
Na: .154
S: .105
all - se
DM: 2.78
Ca: .004
P: .002
K: .015
Mg: .001
N: .014
Na: .004
S: .003
all - x
DM: 23.17
Ca: .693
P: .312
K: 2.353
Mg: .184
N: 2.405
Na: .361
S: .313
Table 3b. Cu, Mo, Se, I, Zn, Mn, Co levels (mg/kg DM) in IRISH SILAGE
year 90 - N
Cu: 375
Mo: 365
Se: 373
I: 344
Zn: 188
Mn: 404
Co: -
year 90 - sd
Cu: 5.641
Mo: .811
Se: .074
I: .172
Zn: 8.401
Mn: 57.704
Co: -
year 90 - se
Cu: .291
Mo: .042
Se: .004
I: .009
Zn: .613
Mn: 2.871
Co: -
year 90 - x
Cu: 10.84
Mo: 1.21
Se: .083
I: .252
Zn: 27.7
Mn: 92.0
Co: -
year 91 - n
Cu: 662
Mo: 657
Se: 588
I: 231
Zn: 233
Mn: 656
Co: 1
year 91 - sd
Cu: 4.728
Mo: 1.276
Se: .169
I: .168
Zn: 11.738
Mn: 55.625
Co: -
year 91 - se
Cu: .184
Mo: .05
Se: .007
I: .011
Zn: .769
Mn: 2.172
Co: -
year 91 - x
Cu: 10.35
Mo: 1.54
Se: .097
I: .275
Zn: 32.4
Mn: 104.4
Co: .400
year 92 - n
Cu: 555
Mo: 524
Se: 497
I: 36
Zn: 517
Mn: 543
Co: -
year 92 - sd
Cu: 5.573
Mo: 1.221
Se: .111
I: .236
Zn: 9.903
Mn: 65.479
Co: -
year 92 - se
Cu: .237
Mo: .053
Se: .005
I: .039
Zn: .436
Mn: 2.81
Co: -
year 92 - x
Cu: 10.15
Mo: 1.55
Se: .096
I: .355
Zn: 28.9
Mn: 109.7
Co: -
year 93 - n
Cu: 52
Mo: 49
Se: 49
I: 16
Zn: 52
Mn: 45
Co: -
year 93 - sd
Cu: 3.882
Mo: .854
Se: .078
I: .189
Zn: 16.298
Mn: 73.904
Co: -
year 93 - se
Cu: .538
Mo: .122
Se: .011
I: ..047
Zn: 2.26
Mn: 11.017
Co: -
year 93 - x
Cu: 9.58
Mo: 1.87
Se: .082
I: .330
Zn: 32.2
Mn: 116.8
Co: .140
all - max
Cu: 39.7
Mo: 18.3
Se: 2.32
I: .98
Zn: 94
Mn: 477
Co: .40
all - min
Cu: 2.8
Mo: .1
Se: .02
I: .04
Zn: 10
Mn: 2
Co: -
all - n
Cu: 1644
Mo: 1595
Se: 1507
I: 627
Zn: 990
Mn: 1648
Co: 1
all - sd
Cu: 5.256
Mo: 1.171
Se: .131
I: .177
Zn: 10.458
Mn: 60.148
Co: -
all - se
Cu: .130
Mo: .029
Se: .003
I: .007
Zn: .332
Mn: 1.482
Co: -
all - x
Cu: 10.36
Mo: 1.48
Se: .093
I: .269
Zn: 29.7
Mn: 103.5
Co: .400 ??
n=1!
Table 4a. Major Element Assessment in IRISH SILAGE: % Samples in each category (see Assessment Criteria) in relation to dairy cow requirement
ca
Very low: .2
Low: 1.8
Normal: 97.0
High: 1.0
dm
Very low: 0
Low: 28.6
Normal: 57.1
High: 14.3
k
Very low: -
Low: -
Normal: 89.3
High: 10.7
mg
Very low: 15.6
Low: 51.7
Normal: 31.8
High: .9
n
Very low: .2
Low: 64.2
Normal: 28.6
High: 7.0
na
Very low: .9
Low: 3.4
Normal: 91.3
High: 4.4
p
Very low: 3.6
Low: 73.5
Normal: 22.4
High: .5
s
Very low: 1.5
Low: 7.1
Normal: 46.2
High: 45.1
Table 4b. Trace Element Assessment in IRISH SILAGE: % Samples in each category (see Assessment Criteria) in relation to dairy cow requirement
co
Very low: -
Low: -
Normal: -
High: -
cu
Very low: 2.2
Low: 62.6
Normal: 34.3
High: .9
i
Very low: 42.7
Low: (38.6 16.9)
Normal: 1.8
High: 0
mn
Very low: .2
Low: .5
Normal: (6.5 89.7)
High: 3.1
mo
Very low: -
Low: -
Normal: 79.2
High: (18.8 1.9 .1)
se
Very low: 69.0
Low: (21.4 4.0)
Normal: 4.7
High: .9
zn
Very low: 6.3
Low: 29.0
Normal: (54.9 9.8)
High: 0
Table 5a. DM (%), Ca, P, K, Mg, N, Na, S levels (% DM) in IRISH HAY
year 90 - n
DM: -
Ca: 4
P: 4
K: 4
Mg: 4
N: 4
Na: 4
S: 2
year 90 - x
DM: -
Ca: .530
P: .218
K: 1.823
Mg: .127
N: 1.080
Na: .140
S: .145
year 91 - n
DM: -
Ca: 1
P: 1
K: 1
Mg: 1
N: 1
Na: 1
S: 1
year 91 - x
DM: -
Ca: .590
P: .240
K: 1.800
Mg: .110
N: 1.560
Na: .210
S: .090
year 92 - n
DM: -
Ca: 8
P: 8
K: 8
Mg: 8
N: 8
Na: 6
S: 8
year 92 - x
DM: -
Ca: .619
P: .229
K: 1.986
Mg: .161
N: 1.446
Na: .283
S: .284
year 93 - n
DM: -
Ca: 4
P: 4
K: 4
Mg: 4
N: 4
Na: 4
S: 4
year 93 - x
DM: -
Ca: .542
P: .233
K: 2.465
Mg: .192
N: 1.300
Na: .215
S: .205
all - max
DM: -
Ca: 1.09
P: .29
K: 3.01
Mg: .29
N: 2.03
Na: .72
S: .42
all - min
DM: -
Ca: .20
P: .16
K: 1.00
Mg: .09
N: .84
Na: .04
S: .09
all - n
DM: -
Ca: 17
P: 17
K: 17
Mg: 17
N: 17
Na: 15
S: 15
all - sd
DM: -
Ca: .178
P: .04
K: .51
Mg: .06
N: .368
Na: .175
S: .081
all - se
DM: -
Ca: .043
P: .01
K: .124
Mg: .015
N: .089
Na: .045
S: .021
all - x***
DM: -
Ca: .578
P: .228
K: 2.049
Mg: .158
N: 1.332
Na: .222
S: .231
 ***Note: Haymaking is uncommon on intensive Irish farms, and few samples are submitted for mineral analysis
Table 5b. Cu, Mo, Se, I, Zn, Mn, Co levels (mg/kg DM) in IRISH HAY
year 90 - n
Cu: 2
Mo: 2
Se: 1
I: 1
Zn: 1
Mn: 4
Co: -
year 90 - x
Cu: 5.00
Mo: .45
Se: .020
I: .310
Zn: 16.5
Mn: 80.5
Co: -
year 91 - n
Cu: 1
Mo: 1
Se: 1
I: 0
Zn: 0
Mn: 1
Co: -
year 91 - x
Cu: 5.00
Mo: 3.10
Se: .280
I: -
Zn: -
Mn: 97.0
Co: -
year 92 - n
Cu: 7
Mo: 7
Se: 4
I: 1
Zn: 7
Mn: 8
Co: -
year 92 - x
Cu: 6.96
Mo: 1.10
Se: .045
I: .200
Zn: 19.5
Mn: 84.5
Co: -
year 93 - n
Cu: 4
Mo: 4
Se: 4
I: 2
Zn: 4
Mn: 4
Co: -
year 93 - x
Cu: 4.52
Mo: 1.75
Se: .033
I: .195
Zn: 18.3
Mn: 85.5
Co: -
all - max
Cu: 11.9
Mo: 3.6
Se: .28
I: .31
Zn: 28
Mn: 266
Co: -
all - min
Cu: 2.8
Mo: .1
Se: .02
I: .16
Zn: 12
Mn: 19
Co: -
all - n
Cu: 14
Mo: 14
Se: 10
I: 4
Zn: 12
Mn: 17
Co: -
all - sd
Cu: 2.302
Mo: 1.173
Se: .075
I: .055
Zn: 4.883
Mn: 65.70
Co: -
all - se
Cu: .615
Mo: .313
Se: .024
I: .028
Zn: 1.41
Mn: 15.94
Co: -
all - x
Cu: 5.84
Mo: 1.34
Se: .061
I: .225
Zn: 18.8
Mn: 84.5
Co: -
Table 6a. Major Element Assessment in IRISH HAY: % Samples in each category (see Assessment Criteria) in relation to dairy cow requirement
ca
Very low: 5.9
Low: 11.8
Normal: 82.3
High: 0
dm
Very low: -
Low: -
Normal: -
High: (100)
k
Very low: -
Low: -
Normal: 100.0
High: 0
mg
Very low: 47.1
Low: 29.4
Normal: 23.5
High: 0
n
Very low: 52.9
Low: 47.1
Normal: 0
High: 0
na
Very low: 20.0
Low: 26.7
Normal: 46.7
High: 6.6
p
Very low: 23.5
Low: 76.5
Normal: 0
High: 0
s
Very low: 20.0
Low: 6.7
Normal: 60.0
High: 13.3
Table 6b. Trace Element Assessment in IRISH HAY: % Samples in each category (see Assessment Criteria) in relation to dairy cow requirement
co
Very low: -
Low: -
Normal: -
High: -
cu
Very low: 50.0
Low: 42.9
Normal: 7.1
High: 0
i
Very low: 25.0
Low: (75.0 0)
Normal: 0
High: 0
mn
Very low: 5.9
Low: 0
Normal: (29.4 58.8)
High: 5.9
mo
Very low: -
Low: -
Normal: 64.3
High: (35.7 0 0)
se
Very low: 90.0
Low: (0 0)
Normal: 10.0
High: 0
zn
Very low: 58.3
Low: 25.0
Normal: (16.7 0)
High: 0
Table 7a. Assessment (breakpoint) criteria used to assess the adequacy of dry matter and Major Element levels in Irish forage as regards suitability for dairy cows
dm %
Very low: <15
Low: 15.0-19.9
Normal: 20.00-24.9
High: >25
n % dm
Very low: <1.30
Low: 1.30-2.49
Normal: 2.50-3.1
High: >3.10
p =
Very low: <.20
Low: .20-.359
Normal: .36-.55
now .33-.47**
High: >.55
k =
Very low: -
Low: <.5
Normal: .50-3.1
High: >3.10
mg = 
Very low: <.15
Low: .15-.199
Normal: .20-.33
High: >.33
na =
Very low: <.10
Low: .10-.149
Normal: .15-.65
High: >.65
ca =
Very low: <.30
Low: .30-.449
Normal: .45-1.20
High: >1.20
s =
Very low: <.15
Low: .15-.199
Normal: .20-.30
High: >.30
**Note: A recent review (1998-1999) of P requirements for dairy cows by Rogers & Dr. Pat Caffrey (UCD) suggests that the "normal (desirable)" range may be lowered to 0.33-0.47% DM, in which case less samples would be classed as "low" and more samples would be classed as "high".
Table 7b. Assessment (breakpoint) criteria used to assess the adequacy of Trace Element levels in Irish forage as regards suitability for dairy cows
cu
Very low: < 5.1
Low: 5.1-9.9
Normal: 10.00-33.0
High: >33
mo
Very low: -
Low: -
Normal: < 2.0
High: (2.0-4.9 5-10 >10)
se
Very low: < .081
Low: (.081-.161-.23)
Normal: .231-.62
High: >.62
i
Very low: < .2
Low: .2-.4-.8
Normal: >.80
High: -
zn
Very low: < 20
Low: 20-24.9
Normal: 25-40-250
High: >250
mn
Very low: < 20
Low: 20-24.9
Normal: 25-40-250
High: >250
co
Very low: -
Low: <.1
Normal: .10-1.0
High: -
Phil Rogers MRCVS, Lucan, Dublin, Ireland​
Fax: 353-46-26154 Tel: 353-46-26740 (Lab)
[email protected]  |  [email protected]
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