Optimal Mineral Nutrition of Cattle and Sheep on Irish
Farms
Phil Rogers MRCVS, Agricultural Research Unit, Teagasc
National Office
A seminar for Teagasc Livestock Specialists, Teagasc Office
Portlaoise, July 22nd, 2003
Irish ruminants ingest minerals from four main sources:
|
Source of mineral |
Associated with |
1 |
Forage |
typically pasture and grass silage |
2 |
Concentrate feeds |
usually mineral-enriched |
3 |
Mineral supplements |
loose mineral mixes, licks, boluses, bullets,
injections, water medication, etc |
4 |
Soil ingestion |
usually involuntary |
Mineral levels in Irish forages depend on many factors,
only some of which are under the farmer’s control. Factors that influence forage
mineral levels include:
|
Factor |
Associated with |
1 |
Field-location especially soil type and height above
sea level |
Bottoms versus higher land; limestone soils versus
peat-, sandstone-, shale- and granite- soils |
2 |
Season & age of regrowth |
lush versus mature forage |
3 |
Local rainfall |
soil moisture |
4 |
Farm management |
Good v poor drainage; liming, fertilisation;
unnecessary S use; sward species & reseeding policy, etc |
|
Major elements (% DM) |
Trace elements (mg/kg DM) |
Forage
|
|
Ca |
P |
K |
Mg |
N |
Na |
S |
Cu |
Mo |
Se |
I |
Zn |
Mn |
Pasture |
Mean |
0.65 |
0.40 |
2.83 |
0.20 |
3.51 |
0.29 |
0.39 |
9.22 |
2.49 |
0.09 |
0.26 |
30.8 |
119.8 |
|
Sd* |
0.18 |
0.09 |
0.76 |
0.05 |
0.96 |
0.17 |
0.10 |
2.67 |
3.09 |
0.15 |
0.18 |
8.7 |
97.0 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Silage |
Mean |
0.69 |
0.31 |
2.35 |
0.18 |
2.41 |
0.36 |
0.31 |
10.36 |
1.48 |
0.09 |
0.27 |
29.7 |
103.5 |
|
Sd* |
0.16 |
0.07 |
0.62 |
0.04 |
0.56 |
0.15 |
0.11 |
5.26 |
1.17 |
0.13 |
0.18 |
10.5 |
60.1 |
*Sd (standard deviation): 95% of values fall in the range (mean
+/- 1*Sd), i.e. 95% of Irish herbage Ca values lay between 0.47 and 0.83 %DM;
99% of values fall in the range (mean +/- 2*Sd), i.e. 99% of Irish herbage Ca
values lay between 0.29 and 1.01 %DM.
The main imbalances found in Irish pasture (3)
were:
From these national data, it follows that optimal mineral
nutrition of Irish cattle and sheep on forage-based diets involves routine
supplementation to ensure balanced inputs of the essential major- and trace-
elements to ensure that neither deficiencies (primary or secondary) nor
toxicities occur.
Useful background data are in the Teagasc Manual, “Control of
Mineral Imbalances in Cattle & Sheep: A Reference Manual for Vets and
Advisers” (1). Siobhan Kavanagh has some spare copies of the
manual, or you can download it from the Teagasc Web Pages (1).
Other details of most topics covered in this seminar are available on the
Teagasc Webpages – see the references at the end of this paper, especially
references 2,
3,
4,
5,
6,
7,
8.
Table 2 summarises the range of values of major- and trace-
elements in TDMI that are classed as “normal” for cattle and sheep.
Table
3 summarises the range of values of trace elements in TDMI
that are classed as “normal” for cattle and sheep.
When assessing the adequacy of total feedstuffs, values
outside of these ranges can be regarded as abnormal (undesirable). The tables
also give the Recommended Optimum Dietary Level (RODL). This usually is at or
above the “mid-normal range”, but physiological and species differences
influence RODL. For example, dairy cows milking on spring grass need more Mg and
P than dry cows in winter; sheep need more Co and less Cu than cattle.
Table 2: Major element levels (%TDMI)
classed as “normal” and the RODLs for cows and ewes.
|
Ca |
P |
Mg |
Na |
K* |
S* |
Normal reference values (%) in TDMI |
.45-1.20 |
.33-.47 |
.20-.33 |
.15-.65 |
.50-3.1 |
.20-.30 |
RODL for Dairy cows |
0.60 |
0.40 |
0.27** |
0.25 |
1.5? |
0.25? |
RODL for Beef cows and Ewes |
0.50 |
0.35 |
0.18** |
0.20 |
1.5? |
0.25? |
Table
3:
Trace element levels (mg/kg TDMI) classed as “normal” in feed, inclusion
rates permitted under EU Feed Regulations, and the RODLs for cows and ewes in
|
Cu |
Mo* |
Se |
I |
Zn |
Mn |
Co |
Normal reference values (mk/kg) in TDMI |
10-39 |
0-2.0 |
.23-.57 |
>.80 |
40-250 |
40-250 |
.10-1.0 |
Max allowed in total feeds for cattle/sheep [EU
Law] |
Cattle 39.8; Sheep
17.0 |
- |
0.57 |
4.55 |
284 |
284 |
11.4 |
RODL for Dairy and Beef cows |
39** |
<2.0 |
0.4** |
4.0 |
75 |
75 |
.85 |
RODL for Ewes |
12*** |
<2.0 |
0.4** |
4.0 |
75 |
75 |
1.0 |
*** Avoid
Cu supplements for sheep except on specific veterinary advice
(1) Dry Cow Mins;
(2) Dairy/Beef Cow Winter Mins;
(3) Tetany Control Mins (for lactating cows at
grass in risk periods);
(4) Calf and grower/finisher Mins;
(5) Fodder Beet Balancer Mins;
(6) Maize silage Balancer Mins;
(7) Balancer minerals for cattle on ad libitum concentrates.
Table 4 gives examples of top-class
formulations for mineral mixes for
COWS AND OTHER CATTLE on grass silage or herbage as the main forage.
Different formulations are needed for cattle on high intakes of special feeds,
like fodder-beet silage, maize silage, or ad libitum concentrates.
Table 4:
Examples of top-class formulations for
mineral mixes for COWS AND OTHER CATTLE
on grass silage or herbage as the main forage.
|
Cows
pre-calving |
Cows
post-calving |
Cows in tetany
time |
Calves/drystock |
Allowance of mineral mix
(g/head/d) |
100(2) |
125(2) |
150(2) |
2g/10kgLW
(2) |
g/100 g
mix |
|
|
|
|
mg/kg
mix |
|
|
|
|
iu/kg
mix |
|
|
|
|
(1)
Never feed cattle minerals to sheep, and vice-versa. Cattle minerals may
cause copper toxicity in sheep. Never feed cow minerals to calves, as scouring
and urinary stones and copper toxicity may follow.
(2) If
recommended daily allowances are above or below those shown, adjust the
trace-element and vitamin levels down or up, accordingly. One would normally
feed 150-180 g minerals in home-mixed lactation diets. Special minerals are
needed if silages based on whole-crop maize or fodderbeet are
fed.
(3) To prevent urinary stones in drystock, feed low levels
(0-3%) of Mg in mineral mixes.
(4) Some authorities double
these amounts of Mn for breeding females, especially in groups with severe
infertility and suspected Mn deficiency
(5) The maximum Se
supplement was reduced to 5 mg Se/cow/d, as from January 1 1996. Do not feed
high Se minerals to cattle within 5 miles of a known Se-toxic farm unless blood
test indicates no risk of Se toxicity.
(6) The higher Vit E levels
are 4-6 times higher than usual (underlined values are more usual). Research in
In theory, sheep also need a wide range of mineral
formulations to cater for different physiological states (pregnancy,
lactation, tetany-risk, lamb fattening minerals, etc). However, because the
total mineral market for sheep is so small relative to that for cattle, the
trade does not provide the optimum range of formulas and reaches a compromise
with a smaller range.
Mg supply in relation to grass
tetany: See
references 1,
9,
10,
11 for more details.
Oral Calmag: The target supplement in the risk
period is 30-50g Mg/cow/d, as 60-100g Calmag (50% Mg)/cow/d, and 10% of that for
ewes (3-7g Mg, as 6-14g Calmag).
Soluble Mg via the water supply: The target supplement
during the risk period is circa 20g Mg/cow/d, as circa 200g Mg chloride (10%
Mg)/cow/d. Do not recommend Mg sulphate (scouring and drop in water intake) or
Mg acetate (too dear). Water medication is unreliable for sheep.
Pasture dusting with Calmag: (Paddocks: 17 kg
powdered Calmag/ha every week; Set Stocked: 34kg/ha every 2 weeks) also is very
effective. Best done on damp grass, with at least 6” of grass cover.
Free-choice DIY 50/50 Calmag/Molasses lick, or High-Mg
Blocks usually are effective but intake cannot be guaranteed, and
some cows may not be protected.
Mg Bullets: Forget the old Mg bullets by
Pfizer. They released too little Mg (only 1g/d each). To prevent tetany, cows
would need at least 6 bullets every month. This would be too dear and give only
20% of the Mg in 2oz Calmag. The newer Optimags release 3g Mg/d
each; to prevent tetany cows need at least 2 of these every month. That is still
too dear, and it will not keep blood Mg normal. Bullets are not as reliable as
2-3 oz Calmag/cow/d. However, dosing bullets that release 3g/ewe/d (and
repeating the dose after 4 weeks) would be a useful, if expensive, way to
control tetany in ewes.
Ca supply in relation to milk
fever: The main
points to remember are to keep Ca inputs low before calving,
supplement with 15g Mg/cow/d in late pregnancy, and avoid calving cows too fat
or too thin.
REMEDIAL
ACTIONS to reduce the risk and severity of bovine hypocalcaemia at calving
include:
Routine actions |
Correct detected causes (For more details (and other advice), see references
1
and 23) |
Specific actions |
|
1. Control body condition
prepartum |
Control prepartum energy intake: Feed cows to calve in good body condition
(body score 3.0-3.5 on a 5-point scale), i.e. not too fat or too
thin. Restrict energy intake of fat cows; supplement
energy intake of thin cows. |
2. Increase Mg intake prepartum |
To ensure high turnover of bone Ca prepartum,
include 10-20 g
Mg/cow/d (say 15 g) in dry-cow supplements (about 15% Mg in mineral
mixes fed prepartum). |
3. Reduce Ca intake in late pregnancy |
To ensure maximal % absorption of Ca
from digesta, reduce Ca intake in the last 6 weeks
prepartum. Avoid Ca supplements prepartum, or keep them <6 g
Ca/cow/d. Dry Cow minerals with 0% Ca are advised in herds with a milk
fever history. Avoid mineral mixes prepartum if the Ca level is
>6%. Total
prepartum intakes of 25-50 g Ca/ day are ideal but are
unattainable, as most common prepartum diets of herbage or silage supply
>55 g/cow/d. [Irish herbage and silage have Ca levels c. 0.65 and 0.69%
DM, respectively. An intake of 10 kg DM of such feed would supply 65-69 g
Ca/d, respectively]. However, if this is appropriate, considering cow body
condition and forage-quality on offer) one can reduce prepartum Ca intake
somewhat by feed restriction and/or the use of low-Ca feeds (such as
maize-silage, grains and roots). HOWEVER: (a) if one can predict calving date
accurately, one SHOULD switch from a low- to a high- Ca intake 1-5
days BEFORE calving, but (b) if calving is delayed for several more
days, the cow will adapt by reducing her % absorption of Ca. In that case,
the high-Ca feed will increase the risk of hypocalcaemia. |
4. P supplements prepartum? |
Herbage and grass-silage are the most common
prepartum diets for cows. Mean P levels in Irish herbage and silage are
0.38 and 0.31% DM respectively. These have ample P for dry cows. Prepartum
P supplements have little effect in preventing parturient hypocalcaemia,
except at impractical levels (30-50 g P or more/cow/d). If low-P
forages (such as beetpulp, fodderbeet etc) are fed, up to 20 g P /cow/d
may be added. |
5. Decrease stress at calving |
Minimising stress reduces adrenalin release and fat
mobilisation at calving, thereby reducing their adverse effects on blood
Ca levels. Comfortable calving boxes and provision of shelter and warmth
at calving help. Closed-circuit TV monitors and careful use of calving
jacks help to keep interference to a minimum. |
6. Increase feed and Ca intake at
calving |
Give palatable feed (such as molassed concentrates + good silage or
hay) to raise the intake of DM and Ca as soon as the cow shows signs of
calving ("pins-down" or "water-bag" visible). |
7. Give Ca +/- P supplement on the day of
calving |
If hypocalcaemia or milk fever occurs at calving in
spite of the methods suggested above, dose or feed susceptible cows
with a very high Ca supplement on three occasions close to calving.
Common Ca supplements include feed-grade limestone flour (Ca
carbonate, 34% Ca) and Dical ( dicalcium phosphate, 22% Ca, 18%
P). Give 125-150 g limestone flour (42-51 g Ca) 12-24h
prepartum; repeat just after calving, and at 12h later.
If low
blood P levels coexist with low blood Ca levels, give 3 doses of 180 g
Dical instead of the limestone flour. |
8. Ca and P supplements postpartum |
High yielders need total daily Ca and P intakes of
circa 90-120 g Ca and 60-80 g P/cow/d after calving.
Dairy nut, fed at circa 7 kg/cow/d should have circa 0.8-1.0% Ca and
0.5-0.7% P. It is important to have the higher levels of Ca and/or P in
dairy nut if cows are on feeds low in Ca and/or P (roots, maize-silage,
high cereal diet). Lactation minerals, for inclusion at
120-140 g/cow/d in 7 kg of home-mixed concentrate feeds, usually contain
12-14% Ca and 9-11% P, but feeds low in Ca or P need special mineral
balancers. |
Optimal dietary supply of N, P, K
and S: Table 5 compares the Recommended Optimum Dietary Level (RODL) for
these elements (%DM) with the mean levels found in Irish forages in the early
1990s:
Table 5.
Comparison of Recommended Optimum Dietary Level (RODL) of
N, P, K and S (%DM) with the mean levels found in Irish forages in the early
1990s
Forage
|
N |
P |
K |
S |
RODL |
2.70 |
0.40 |
1.50? |
0.25? |
Pasture |
3.51 |
0.40 |
2.83 |
0.39 |
Silage |
2.41 |
0.31 |
2.35 |
0.31 |
Pasture, especially young lush pasture,
usually had excessive amounts of N, K and S for optimum dairy cow
nutrition. This can be associated with loose faeces and impaired absorption of
other elements by cows, notably Mg, I, Cu and Se.
Silage usually had suboptimal N and P for dairy cows,
and the K levels were somewhat too high. The S levels were also high, probably
due to use of unnecessary S fertilisers and/or Cosil silage additive.
See reference 22. Ovine urinary calculi are typically Mg
phosphate, precipitated in an alkaline urine.
Causes of urinary calculi: Calculus formation has many causes, of which the mineral
(P, Mg, Ca, Na) level in feed is only one factor. It involves: reduced water
intake, reduced urine output, cold environment, alkaline urine pH and genetic
susceptibility. Other possible factors are: urinary infection; mucilaginous
material in urine; low roughage intake and saliva secretion; increased P
retention; vitamin A deficiency; excess intake of fluoride, oxalate, sodium
bicarbonate and silica. However, precipitation of magnesium phosphate is the
basic cause in intensively fed sheep. Urolithiasis is very rare if the total
feed contains P < 0.46% and/or Mg < 0.23% DM respectively. The higher the
P and Mg levels, the greater the risk. Low Ca/P ratios increase P absorption. Mg
availability is high on cereal-based diets. Lambs on concentrates need less Mg,
possibly 50% less, than lambs on grass diets.
Control and
prevention of urolithiasis (urinary calculi) in lambs:
Optimal supply of Cu, Co, Se and I: It is important to advise adequate supplements of these
trace elements as an insurance against deficiencies. Cattle should
get all four of these routinely. Mn and Zn usually are added but are not as
important nationally as the other four. The most important ones to remember are
those for cows and ewes: See Table 3, above, for the RODLs.
Table 6 shows the recommended trace element supplement (mg/head/d)
for cows and ewes. Note that ewes get 10% of the cow dose, except for Cu [use
only on vet advice] and Co, where the top dose for ewes is 20% of the top cow
dose.
Table 6.
Recommended trace element supplement (mg/head/d) for cows and
ewes.
Animal |
Cu* |
Se** |
I |
Co |
Mn^ |
Zn*** |
Cows (mg/head/d) |
350-450 |
3.0-5.0 |
12-60 |
5-10 |
335-415 |
335-750 |
Ewes (mg/head/d)
|
(0-18) |
.30-.50 |
1.2-6 |
0.5-2 |
33-42 |
33-75 |
The
lower levels are for routine continuous use. With the following
exceptions, the higher levels are advised for national use in the Teagasc
5-month mineral programme for cows (1 month prepartum to 5 months postpartum),
or as needed in groups of cattle or sheep at risk of severe deficiency,
^ Some
authorities advise much higher Mn supplements (up to 980 mg/cow /d) in
herds with severe infertility due to suspected Mn deficiency. A pro-rata dose
for ewes would be up to 98 mg Mn/d.
* Give
Cu to sheep only on veterinary confirmation of Cu deficiency.
** Within
5 miles of known Se-toxic farms, reduce the Se supplement to about
50% of the lower level, unless blood test confirms Se deficiency in the
group.
*/**
Ionophores (monensin etc) increase the retention rate of Cu and Se by
ruminants. If ionophores are fed, avoid the higher levels of Cu and Se
supplements, unless blood test suggests that higher levels are needed.
*** Zn
supplement of up to maximum is advised if high-Ca diets are
fed.
See the Teagasc
Manual (1) for the daily targets for
recommended trace element supplements for other classes of stock, and for
vitamin supplements for all classes.
Copper toxicity in sheep and
calves:
Excessive Cu inputs can poison
all breeds of sheep. Island breeds and crosses (
Under current
EU Legislation, complete sheep feeds must not exceed 15mg Cu/kg in total feed
(17mg Cu/kg total feed DM). Assuming a maximum DM intake of 2 kg/ewe/d, the
EU permits a maximum oral intake of about 34mg Cu/ewe/d (less, pro-rata,
for lighter sheep). To be safe (in the case of susceptible breeds), stay below
the maximum permitted by the EU.
Prevention of Cu toxicity:
Selenium toxicity (selenosis): This may affect all
livestock, especially cattle and sheep. Several plant species such as Astragalus
(loco weed and milk vetch), Onopisis (goldenweed) and Zylorhiza (woody aster)
are Se accumulators.
Acute selenosis may follow a single consumption of
very highly seleniferous plants. This occurs in
Chronic selenosis occurs in prolonged ingestion of
toxic but lower Se levels than in acute selenosis. It has two forms -
Blind staggers and Alkali Disease. The latter is the
form more usually seen in
(1) Blind staggers occurs when animals ingest
water-soluble Se compounds found naturally in accumulator plants.
The signs occur in 3 stages. Stage 1 shows wandering, stumbling
over objects, anorexia, visual impairment. Stage 2 is a more
severe form of stage 1, in which the front legs seem unable to support the
animal. Stage 3 shows blindness, tongue paralysis, inability to
swallow, rapid and laboured respiration, salivation, and low temperature. The
animal dies within a few hours of the onset of Stage 3. The toxic action in
Blind Staggers may show a delay between the stages. Stages 1 and 2 may go
unnoticed. Weeks later, the animal may show signs of Stage 3 and die. It is more
difficult to diagnose in sheep because the stages are not as well defined as in
cattle. Toxic amounts of Se can also cause birth defects in offspring from dams
fed such levels.
(2) Alkali Disease, the most common
manifestation of selenosis in
The most effective means to prevent selenosis is to remove
the animals from the seleniferous areas. Dilution of high Se feeds with low Se
feeds in a mixed ration will help to prevent toxicity. Recognition of
seleniferous plants, proper land management, and grazing control are all
necessary to completely prevent selenosis. In the early stage of an outbreak,
dosing with a high-S cocktail may halt the progression of the disease. For
details, see reference
29.
Treating the soil with sulphates, to increase the S:Se
ratio in forage, rarely depresses Se uptake by accumulator plants enough to
guarantee their safety. Feeding a higher protein diet may reduce Se toxicity;
animals fed the same amount of toxic selenium but fed a higher protein diet
lived for a few more days than those animals fed a low protein diet. See reference
1 for more details.
Lead toxicity (plumbism):
Cattle and sheep ingest
large amounts of soil (cattle 5-15% of TDMI; sheep 15-35% of TDMI). If the soil
has high levels of heavy metal (Cd, Pb, Zn) ingestion of the metal via soil can
be high enough to poison the animals. Soil near abandoned lead- or zinc- mines
or smelters may have high Pb levels. Ingestion of Pb-contaminated soil has
poisoned cattle in
However, ingestion of Pb from contaminated silage (battery chopped in!),
or licking painted timber/boats (red-lead paint is banned now but timber painted
with it can remain toxic for decades) are common causes of poisoning. Other Pb
sources are: putty, tarpauliin, sump-oil, and contaminated herbage near
motorways.
Pb toxicity can kill cattle, even adult cows, very quickly.
If diagnosed, the source of Pb must be found and removed from the cattle.
Affected cattle usually can be saved if the Pb source is removed and
Pb-chelation therapy is started immediately.
The Teagasc Intranet has useful notes on how to search the
Abstracts Databases to best advantage. To find these notes, search under the
keywords “Lendac” and “OVID”. Note that the files on the Intranet refer to
OVID/WebSpirs5. We have moved to DataStar & Dialog recently, but have not
mounted the data specific for those databases yet. However, the files on Lendac
are a useful introduction to focused searching.
Also, you can access PubMed Medline [ http://www.ncbi.nlm.nih.gov/PubMed/medline.html ] free,
without passwords. It has vast amounts of data on animal nutrition and disease.
Google
Advanced Search [ http://www.google.com/advanced_search
] is very useful to locate nutritional articles on the WWW, for example from
other research institutes and university sites. It is also useful for sourcing
veterinary products and nutritional supplements.
BABELFISH Online Translation is a most useful free service. It allows one to paste about 150 words of text from any of several languages into the system and it outputs a reasonable translation. See notes on its use at http://www.tnet.teagasc.ie/hq/staff-dev/InternalTrainers/translation.asp
To summarise the main points of this seminar, and to impart
the basic principles of balanced mineral nutrition of ruminants to their
clients, advisers should remember the “MOST FARMS”
mnemonic:
M |
Multiple deficiencies are common;
|
O |
Often (not always) cause problems;
|
S |
Signs (summarised by the letters of
SIGMARA; see below); |
T |
Treatment (only after diagnosis); |
|
|
F |
Fixed-rate supplementation is best |
A |
Ad-lib is second-class |
R |
Relative costs: Vet products (boluses, injections) 25-35
euro/cow/year; water medication (Mg+trace-elements) 18-24
euro/cow/year; simple mineral mixes in/on feed 12-16 euro/cow/year
|
M |
Mineral mixes – at least 4 formulas for cattle: Dry
Cow Min; Lactation Min; Tetany-control Min; Drystock Min; + special
balancer Mins for fodder beet and maize silage |
S |
Simplest solution is the cheapest and best, i.e.
fixed-rate high-spec minerals in feed, on feed, or in water supply,
especially for the most critical 5 months (1 month pre-calving to 4 months
post-calving) |
Signs (SIGMARA - the S in
MOST, above)
S |
Survival (re abortion, stillbirth, early postnatal
death, tetany, milk fever) |
I |
Infertility (esp Mg, P and I); and
Immunity (esp Cu, Co, Se, I re neonatal
scour/pneumonia/joint-ill, mastitis, metritis, parasitic, etc)
|
G |
Growth (esp P, Cu, Co; maybe Se, I) |
M |
Milk yield (esp low Mg, low P, Mo scour, severe Co
deficiency) |
A |
Appetite (esp Mg, P, Co) |
R |
Retained placenta (esp I, Se, Cu, Ca/Mg) |
A |
Add:
Lameness (Cu def, P def, Zn def, Se tox); scour (Mo-induced
Cu def; Co def; low immunity scours); calculi; convulsions
(tetany, maybe hypocal, Pb tox) |
Note that the
Teagasc recommendations for supplementary trace element inputs to cattle and
sheep are 2-4 times higher than those recommended in most other countries. This
is because Irish research over >30 years has confirmed that our ruminants
NEED these high inputs. If, to follow foreign advice, we reduce our levels of
supplementation, the blood mineral status of our herds and flocks will fall
accordingly.
MANUALS ON CATTLE/SHEEP MINERAL
NUTRITION & FURTHER
1.
Control of Mineral Imbalances in Cattle
and Sheep: A Reference Manual for Advisers and
Vets |
http://www.tnet.teagasc.ie/Grange%20Pages/dat//3control.htm |
2.
Teagasc Farm Nutrient Profile:
Reference Information for Professionals
|
http://www.tnet.teagasc.ie/Grange%20Pages/dat/2manual.htm |
3.
Chemical composition of
Irish Forages - Grass, Silage &
Hay |
http://www.tnet.teagasc.ie/Grange%20Pages/dat/0forage.htm |
http://www.tnet.teagasc.ie/Grange%20Pages/dat/0feedcomp.htm | |
http://www.tnet.teagasc.ie/Grange%20Pages/dat/abattoir.htm | |
6.
Grange Lab Breakpoints to assess blood
samples in Cattle and Sheep
|
http://www.tnet.teagasc.ie/Grange%20Pages/dat/0breaks.htm |
7.
Biochemical variables and
trace element analyses for Animal Health
Professionals |
http://www.tnet.teagasc.ie/Grange%20Pages/dat/lab_vars.htm |
8.
The Role of the Lab in the
Investigation of Herd Health Problems: Intelligent Use of Lab
Diagnosis |
http://www.tnet.teagasc.ie/Grange%20Pages/dat/lab_int_use.htm |
MINERAL SUPPLEMENTS FOR FARM
ANIMALS
http://www.tnet.teagasc.ie/Grange%20Pages/dat/mgsupbov.htm | |
10.
Mineral Mixes for Cows & Other
Cattle: Practical options for dairy & beef
herds |
http://www.tnet.teagasc.ie/Grange%20Pages/dat/mins_bov.htm |
11.
Routine prevention of mineral
deficiencies in beef herds |
http://www.tnet.teagasc.ie/Grange%20Pages/dat/0min2000.htm |
12.
Iodine Supplements for Livestock -
Cattle, Sheep & Horses |
http://www.tnet.teagasc.ie/Grange%20Pages/dat/iodsupp.htm |
http://www.tnet.teagasc.ie/Grange%20Pages/dat/maizesil.htm |
COMMON PROBLEMS RELATED
TO MINERAL IMBALANCES
http://www.tnet.teagasc.ie/Grange%20Pages/dat/anaemia.htm | |
15.
Urea, nitrate & nitrite poisoning
in cattle & sheep: Sources, toxic doses, treatment and
prevention |
http://www.tnet.teagasc.ie/Grange%20Pages/dat/ureanitr.htm |
http://www.tnet.teagasc.ie/Grange%20Pages/dat/scourall.htm | |
http://www.tnet.teagasc.ie/Grange%20Pages/dat/picaurin.htm | |
http://www.tnet.teagasc.ie/Grange%20Pages/dat/poorcoat.htm | |
http://www.tnet.teagasc.ie/Grange%20Pages/dat/infertil.htm | |
http://www.tnet.teagasc.ie/Grange%20Pages/dat/ketosis.htm | |
http://www.tnet.teagasc.ie/Grange%20Pages/dat/cutox.htm | |
22.
Control and prevention of
urinary calculi in lambs and
calves |
http://www.tnet.teagasc.ie/Grange%20Pages/dat/calculi.htm |
23.
Control of Calcium
Imbalance, Hypocalcaemia & Milk Fever in
Cows |
http://www.tnet.teagasc.ie/Grange%20Pages/dat/milkfeve.htm |
24.
Herd Illthrift & Poor Performance
(Growth, Milk Yield or Fertility) in
Cattle |
http://www.tnet.teagasc.ie/Grange%20Pages/dat/illthbov.htm |
http://www.tnet.teagasc.ie/Grange%20Pages/dat/lamebov.htm | |
http://www.tnet.teagasc.ie/Grange%20Pages/dat/milkmast.htm | |
27.
Investigation and control of abortion,
perinatal & early postnatal problems in cows /
calves |
http://www.tnet.teagasc.ie/Grange%20Pages/dat/perinatb.htm |
28.
Lamb
Illthrift |
http://www.tnet.teagasc.ie/Grange%20Pages/dat/illthovi.htm |
29.
Rogers PAM, Arora SP,
|
Selenium toxicity in farm
animals: treatment and prevention. Irish Veterinary Journal, 43,
151-153 |
GENERAL INFORMATION AND SEARCH
OPTIONS
30.
A Brief Guide for Teagasc
Staff on how to find relevant Titles/Abstracts on
Lendac |
http://www.tnet.teagasc.ie/hq/staff-dev/ittraining/LendacPhil.asp |
31.
Search
Options to find Scientific Data on Medicine,
Veterinary Medicine, Animal Health, Animal Welfare, & Life Sciences
|
http://www.tnet.teagasc.ie/Grange%20Pages/search.htm |
32.
Extensive Links to Agriculture,
Veterinary Medicine & Life Science
Pages |
http://www.tnet.teagasc.ie/Grange%20Pages/veturls.htm
|
33.
Extensive Links to General
Encyclopedias, Dictionaries,
Calculators |
http://www.tnet.teagasc.ie/Grange%20Pages/veturlsen.htm
|
http://www.google.com/advanced_search | |
http://www.vet.cornell.edu/consultant/consult.asp | |
http://ie.altavista.com/babelfish
|
40 kg of 20% DM
silage/head/d with Cu levels of 9 mg/kg DM,
+ 4.5 kg of 88% DM
beef-nuts with Cu levels of 60 mg/kg DM,
+ one 24g CuO (80% Cu) bolus, said to have an
active release over a period of 150 days:
Assuming a recommended total input of 550 mg
Cu/head/d, is the mean daily Cu input (a) too low, (b) OK, or (c) too high?
(Hint: calculate the DAILY inputs from each
component, then the total DAILY input, and compare that with the RECOMMENDED
daily intake)
70 kg of 20% DM
grass/head/d with I levels of 0.2 mg/kg DM,
+ 3 kg of fertility-nut
with 8 mg I/kg,
+ one Ionox bolus containing 2700 mg I, said to
have an active release over a period of 150 days:
Assuming a recommended total input of 64 mg
I/head/d, is the mean daily I input (a) too low, (b) OK, or (c) too high?
(Hint: calculate the DAILY inputs from each
component, then the total DAILY input, and compare that with the RECOMMENDED
daily intake)
(a)
Excess Mg in the diet?
(b)
Excess P in the diet?
(c)
Not enough Na in the
diet?
(d)
Not enough Ca in the diet
relative to P?
(e)
Decreased water intake?
(f)
All of the above in
combination?
The farmer decided to take a 10-day break,
starting on April 10th. He hired a relief worker to take over while he was away.
The relief-worker fed nut (a) to the steers and nut (b) to the cows for 10
consecutive days. He got the feeding rate right (2 kg/head/d) but had switched
the nuts in error. What did the farmer probably find when he came back after the
week’s break?
that several cows
had died of tetany?
that all of the
steers were scouring badly?
that some steers
had urinary obstruction due to calculi?
that the relief
worker had skipped to
all of the
above?
Within 1 month, 20% of the lambs had died, or
were showing the following symptoms: kicking at the belly, grinding the teeth,
anorexia, weakness, jaundice and dark-coloured urine.
Without telling the CoOp about
the CuO dose given before housing, the farmer decided to lodge a claim for
damages against the Co-Op.
Would the CoOp be likely to
contest the claim in Court?
If no, why
not?
If yes, would the farmer be
likely to win the case outright? Why?
If, on advice from a shrewd nutritional consultant, the CoOp lawyer induced the farmer to admit to giving the 4g CuO capsule/head before housing, would the judge be likely to cut the damages by up to 50%?
If yes, why?
1. What causes copper
deficiency in dairy cows?: Irish forage is marginally deficient in Cu
for cattle, but most serious Cu deficiency in cattle and sheep is secondary, due
to the presence of Cu-antagonists, especially high ingestion of Mo, S and Fe.
See Cu Deficiency in the Teagasc Manual (1).
What to do in low lime / high molybdenum areas?
What to do in high molybdenum areas?: Use lime, as needed, possibly
reducing the application slightly, BUT provide Cu supplements to the cows at the
TOP end of the Teagasc recommended rates (i.e. at 450 mg Cu/cow/d for at least 5
months (1 month pre- to 4 months post- calving). See Table 4 in the Teagasc
Manual (1)
and references (9,
10,
11,
13).
In a few herds (<10 herds in 20 years), supplements of 500-700mg Cu/cow/d
were needed to control severe Cu deficiency. Note that in one trial in a
Cu-deficient herd in
2. Is skin application of
tincture of iodine tincture on the inside of a cow’s leg reliable to prevent I
deficiency?: Spraying of 8-9ml of 5% tincture of iodinw/cow/week on the
thin skin of the flank fold maintains blood I levels in the normal range for c.
1 week. However, Plasma (and milk) I levels go very high (offscale) in the first
day, and fall thereafter until the next application. Thus, they are not as
stable as the I levels in blood/milk of cows fed 60mg I/cow/d via the feed or
the water supply. The method is best reserved for SUCKLER cows that cannot be
given I cheaply by any other way (in feed or in water, or in mineral
licks).
Are there any quality assurance issues with milk
from cows treated in that way?: Yes! Medical researchers are
concerned that milk should not contain excessive I levels. High I in milk can
cause toxic goitre in milk-fed infants. Therefore, as milk I values can be very
high 24 hours after skin-application of a high dose of I, the method is NOT
recommended for lactating dairy cows.
3. Which iodine boluses
are best?: At present, to supply I to cattle at grass, IONOX (Bayer) is
the best bolus on the Irish market. It has 18mg I (plus generous amounts of Se
and Co)/bolus. If no other I supplement is used, the recommended dose is 2-3
boluses/cow every 5-7 months.
However,
when one considers that Cu and Mg (at least) must be supplied also, IONOX is an
expensive way to give I, Se and Co. Provision of appropriate high-spec Min-Vit
Mixes IN the feed or ON the feed, or provision of soluble minerals (Mg and
trace-elements) via the water supply, are cheaper and more effective ways to
control all the common mineral problems together.
4.
How does one get minerals into dairy cows that are fed straight
ingredients, e.g. citrus pulp, at grass?: (1) Add the correct amount of
the desired mineral mix to the day’s allowance of straight ingredient. For
example, a farmer may want to feed a DIY mix of 3 kg straights (2 kg rolled
barley + 1 kg citrus)/cow to high-yield cows in May. He/she could add 130-150g
high-Mg Tetany Control Mineral to each 3kg of straights, preferably including
circa 5% molasses at the final stage to prevent the mineral from settling out of
the mix.
CATTLE
5. What mineral
specification is needed for high concentrate feeding? Will a general cattle
mineral suffice?: Individual concentrates vary widely in their mineral
content (see reference 4). Depending on their individual ingredients, high
concentrate feeds for growing ad finishing cattle usually need extra Ca, Na and
Vitamin E over and above the amounts in mineral mixes for use in forage-fed
cattle.
(%DM) |
RODL
(Dairy) |
RODL
(Beef) |
Beetpulp, dried,
Molassed |
Barley |
Maize |
Citrus
pulp |
Corn
gluten feed |
Soya
50% CP |
Cottonseed
exp. |
|
|
|
|
|
|
|
|
|
|
Ca |
0.60 |
0.50 |
0.68 |
0.07 |
0.04 |
1.22 |
0.17 |
0.39 |
0.20 |
P |
0.40 |
0.35 |
0.10 |
0.38 |
0.29 |
0.11 |
0.90 |
0.72 |
0.82 |
Mg |
0.27 |
0.18 |
0.32 |
0.13 |
0.14 |
0.18 |
0.34 |
0.32 |
0.38 |
Na |
0.25 |
0.20 |
0.27 |
0.02 |
0.03 |
0.03 |
0.10 |
0.05 |
0.03 |
One should aim to have the content of each
mineral the TOTAL feed DM at or near the optimal RODL for that mineral, as in
Mineral Targets for cattle & sheep, above.
6. Is feeding of minerals
needed if a herd/flock has good performance and no history of mineral
deficiency?: As stated in the Executive Summary, because Irish forages
have MULTIPLE mineral deficiencies, one can expect MULTIPLE mineral deficiencies
in most unsupplemented Irish herds/flocks. However, NONCLINICAL deficiencies are
very common in Irish herds/flocks. Mineral supplementation of such animals does
NOT increase animal health/profitability in easily detectable ways. That said, I
advise ROUTINE use of mineral supplements to prevent the possibility of
subclinical or clinical deficiency; I see it as a form of “insurance policy”.
All concentrate feeds for drystock should contain min-vit supplements,
especially in autumn and winter.
Is it
advisable to have house- or car- insurance if there is no history of a need to
claim on such insurance in the past? Most people take out insurance just in case
… but hope never to actually need it!
7. Would high magnesium
lime cut down on the risk of tetany?: Pure MgO has 60% Mg; Feed-grade
Calcined magnesite (Calmag) is 85% pure MgO, i.e. has circa 50% Mg. In contrast,
dolomitic limestone (“magnesium lime”) has maximum of 15% Mg. It should NOT be
used in an attempt to prevent tetany, as plant uptake of Mg from fertiliser is
poor. Anyway, most tetany is NOT due to primary Mg deficiency, but to the
presence of Mg-antagonists (especially lush grass, high in K and N).
Effective control of hypomagnesaemia in cattle and shhe depends on direct
supplementation with adequate oral Mg. See Mg supply re grass
tetany,
above.
8. Some farmers use high
selenium supplements to reduce lamb mortality. Is there a risk of these being
too high?: Sheep are not as prone to Se toxicity as cattle, but can be
poisoned if the Se inputs are high enough. This rarely happens due to
farmer-error in supplementation, but has happened when high-Se drenches sludged
because of inadequate mixing of the dosing-pack between sheep. See the section
on Se toxicity and reference 29 above.
What dietary Se levels are
recommended?: The optimum range of dietary Se for Irish sheep and cattle
is 0.20 to 0.57mg/kg TDMI, preferably in the upper end of that range. Se is
especially advisable in late pregnancy and leading up to, and during, the
breeding season.
What are the EU limits on
inclusion?: The EU permits 0.50mg Se in total feeds (88% DM) for adult
cattle and sheep. This converts to 0.57mg Se/kg TDMI. As Irish forage has circa
0.09mg Se/kg DM, a supplement of up to 0.48mg Se/kg DM falls into the “permitted
area” under EU regulations.
9. How available is
dietary P for sheep?: This is not easy to answer, because the published
research data are very variable – usually in the range 20-50% of P intake.
If a lot of dietary P is excreted, could this
reduce the need for P fertilisation at grass?: One should ignore much
of the faecal P excreted by grazing animals when calculating the amount of P
fertiliser needed for adequate pasture growth. This is because faecal deposition
is very localised and faecal P does not travel far from the dungpats. Evenly
applied slurry is more reliable – it gives much better coverage over the dressed
areas. One can use slurry (and artificial P fertiliser) very effectively. One
should aim for circa 0.30% P, or more, in herbage DM for sheep and suckler cows,
and circa 0.35% P, or more, in herbage DM for dairy cows and rapidly growing
young cattle.
10. Bioplex minerals for all categories of livestock – what is the thinking on these?: There is little solid evidence from independent research that bioplexed trace elements increase animal health or productivity more effectively than adequate supplements of inorganic trace elements. Bioplexed Se and Zn are absorbed 2-4 times more effectively than inorganic Se or Zn, and are incorporated more effectively into biologically active enzymes. However, the price differential is huge – for Se more than 105-times the cost of inorganic Se. Therefore, on the basis of their exorbitant cost, I do not recommend their routine inclusion in mineral mixes.
One exception is
in cow herds with non-responsive hoof lameness/laminitis with suspect Zn
deficiency [very rare, and usually due to dietary Ca excess relative to Zn]. In
that case, I would advise bioplexed Zn/Zn methionate for a few weeks. If this
clearly improved the lameness, I would advise THAT farmer to use bioplexed Zn
routinely.
However, MOST lameness has NOTHING to do with Zn
deficiency. See advisory notes on laminitis/lameness (25).
11. Most maize balancers are short on
calcium, particularly at high inclusion levels of maize. How do you get over
that without exceeding the EU recommended level for some of the other trace
elements?: Simply add extra Ca as limestone flour (feed-grade Ca
carbonate, 34% Ca). See also reference 13.
12. High copper levels in deer diets:
what is the legislation on copper inclusion levels?: If their diets are
deficient in Cu (and have Cu antagonists - Mo, S, etc), deer (like cattle) are
very prone to Cu deficiency. Deer should receive Cu supplements at the same rate
(mg Cu/100kg LW) as cattle, i.e. a deer of 60kg LW would receive a Cu supplement
of up to 45 mg Cu/d (circa 10% of the Cu supplement of a 600kg cow). EU Animal
Feed Regulations allow a maximum of 35mg Cu/kg in total feeds (88% DM) for deer;
this is equivalent to 39.8mg Cu/kg TDMI.
Any
quality assurance implications here?: To ensure optimal deer health and
quality of meat, ensure that they receive an adequate Cu supplement.