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This article was published in 1978
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Phosphorus Deficiency in Cattle
M.R. Barry, B.V.Sc., Veterinary Inspector, Albury
An interesting clinical problem came to notice when an owner at Howlong rang on 3.11.1977 to say that two weeks earlier his cattle had been injected at a neighbour's yards with a 5-in-1 vaccine. One cow died some days later. It was thought to have broken its leg as the left foreleg had swollen badly but no autopsy was carried out.
By 3.11.1977, a second cow showed swelling of its leg and shoulder and this prompted the telephone enquiry. The swelling in each cow was on the same side as the site of vaccination on the left neck. The possibility of infection was considered and treatment with penicillin and streptomycin was begun by the owner.
The herd was inspected the following morning and the cow with the swollen shoulder was restrained with a rope in the paddock. The whole left shoulder region of this cow was swollen and hard. The shoulder bulged out from the chest wall. Her condition was otherwise reasonable. Drought conditions prevailed in the area.
Several other Shorthorn cows showed slight lameness or stiffness, but the remainder of the cows seemed normal. Treatment with antibiotics of those cattle favouring a leg was suggested.
On 18.11.1977 a call was made at the farm to follow up the matter. It was found that the second cow had died. It had eaten well until near to death. A private practitioner had been consulted and he had also tentatively considered that the swelling in the first two cattle was due to infection.
By 18.11.1977 a third cow appeared to be sick and two more walked stiffly. The herd consisted of a line of Shorthorn cows brought from a drought area in 1976, together with locally bred Herefords and a few Angus, Jerseys and crossbreds. The initial cases were present only in the Shorthorn cattle, but they had been vaccinated at the same time as the others, as a single herd boxed together.
The delay of a month from vaccination to the first appearance of symptoms in these later cases suggested some cause other than infection following vaccination, but the involvement of only Shorthorns was not understood.
On the afternoon of 7.12.1977, the owner rang to advise that another cow had developed a large swelling in the shoulder. The property was visited the following morning and the cattle were inspected in various paddocks.
A fat Shorthorn cross cow was carrying its right front leg. An Angus cow, with calf at foot, walked stiffly. Another Shorthorn lactating cow also appeared lame. At this stage, the owners revealed that cattle had been seen to chew bones.
Arrangements were made to have the fat Shorthorn cross cow slaughtered at a local knackery and for any lame cattle in the herd to be yarded for bleeding to establish their blood phosphorus levels as phosphorus deficiency was suspected.
When the crossbred cow was slaughtered on 12.12.1977, it was found to have a fractured right humerus with overriding of the two portions of the bone.
Blood samples collected from it and eight other affected cows in the herd revealed blood inorganic phosphorus (B.I.P.) levels, as shown in Table 1:
TABLE 1.
| SAMPLE | DESCRIPTION | B.I.P. (Serum) mg/P100 ml. |
|---|---|---|
| 1 | Red cow | 0.9 |
| 2 | Roan cow | 1.1 |
| 3 | Red cow | 1.4 |
| 4 | Red & White cow | 1.3 |
| 5 | Angus | 1.7 |
| 6 | Roan | 1.5 |
| 7 | Roan | 1.7 |
| 8 | Roan | 1.3 |
| 9 | Slaughtered cow | 3.5 |
A phosphorus supplement of oat husks (2 bags) and 30 lbs, of Calstockfos (R), (Shirleys) was fed to the herd continuously from mid December 1977 until late February, 1978 when the cows stopped eating the supplement. No further fractures have been observed.
Lameness and stiffness also decreased and are no longer apparent to the owner.
The blood samples were collected from the jugular vein into 10 ml Vacutainers, chilled in a refrigerator for 4 hours and sent in a foam vaccine container box, with ice bricks, to the Regional Veterinary Laboratory, Wagga.
This serum method is a much more convenient way of obtaining an indication in the field of the phosphorus status of cattle than the whole blood and trichloroacetic acid (TCA) method.
This serum method of estimating the phosphorus status of cattle requires, however, that the samples reach the laboratory before haemolysis or bacterial decomposition occurs.
Blood inorganic phosphorus levels in cattle are difficult to interpret unless they are at the lowest levels. Blood inorganic phosphorus levels in the range of 4 - 8 mg/100 ml in cattle could generally be considered to indicate adequate phosphorus in the diet.
Venipuncture and excitement have been shown to raise blood inorganic phosphorus levels.
The content of inorganic phosphorus also increases during the storage of blood due to the hydrolysis of organically bound phosphate.
The herd described above was apparently not the only one suffering from phosphorus deficiency, as several other herds showed obvious bone chewing or depraved appetite soon after in areas such as Jindera, Table Top, Walla and Henty.
There are many different sources of phosphorus available for supplying supplements to beef cattle, but not all may be available in a given area, e.g. bone-meal was unobtainable at Albury during this recent period of deficiency. Blocks are generally available but although convenient, they are costly. If an owner has time or labour available, he can provide cheaper supplements.
Superphosphate should not be fed to livestock as it is because of its high level of fluorine, but if superphosphate is dissolved in water it forms a supernatent which contains virtually no fluorine but 7.6% soluble phosphorus. This can be a cheap method of phosphorus supplementation where trough water is the only water supply.
Other sources of phosphorus have been suggested by various authors and an appropriate available one can be selected.
REFERENCES
A. Collection and Despatch of Material for Laboratory Examination, Veterinary Services Staff, N.S.W, Department of Agriculture 5th Edition, 1974
B. 'Phosphorus Status and Supplementation of Grazing Beef Cattle' by M.H. Round, Department of Agriculture and Fisheries, South Australia, Livestock Brach, Technical Information Circular 26, July 1976
C. Phosphate Supplementation of Cattle by B.R. Sundstrom. Reprint from Agricultural Gazette of N.S.W., Vol. 85, No. 1., February, 1974
D. Phosphorus and Fertility in the upper Hunter D. Sharp & B. Thompson, Dairy Topics, No. 17, January 1978. Department of Agriculture, N.S.W.