Molybdenum Poisoning in Cattle on Pumice Land and Its Control by Injection of Copper

New Zealand Journal of Agriculture, Volume 95, Issue 3, 16 September 1957, Page 218

Molybdenum Poisoning in Cattle on Pumice Land and Its Control by Injection of Copper

By.

I. J. CUNNINGHAM,

Superintendent, Department of Agriculture Animal Research Station, Wallaceville deficiency in beef animals has been evident in some areas in New Zealand in greying of the coats of Aberdeen Angus cattle and unthriftiness. The condition can be prevented by increasing copper supplies to the animals, and effective and cheap control of the disease has been achieved by a method of subcutaneous injection of copper compounds arising from research into the disease by the Wallaceville Animal Research Station. Copper cerates for treating animals can now be bought and farmers can get advice on their use from veterinarians or Livestock Instructors.

A BERDEEN ANGUS yearlings which graze over some of the pumice hills near Wairoa do not have the deep black coats characteristic of their breed. The black is replaced to a varying degree by grey. In slightly affected animals the grey occurs only round the eyes, like a spectacle frame; in more severe cases much of the coat is ..mottled grey-black; . and in very severe cases, the whole coat is grey and has a dull, lifeless look. The severely affected animals are undersized and unthrifty, but the less severely affected ones do not show any marked failure of growth or lack of .thrift. The disease is of most importance in weaners, for calves . under 3 months

of age and most animals over 18 months seldom show any signs. Some of the breeding cows, presumably among those who have borne a calf regularly each year, show greying, but not many lose condition. The main economic loss is therefore from the effect on weaners and comes chiefly through reduction in selling price of stunted animals and from occasional deaths,! j especially in the winter after weaning. The incidence of the disease varies from year to year. In some years only an odd . weaner is affected and in others 25 per cent, or more are so poor that they are drafted and sold as culls; the remaining animals are below desired size. The condition is associated with a slight deficiency of copper and an excess of molybdenum in the fodder which together have the effect of pro-

during a copper deficiency in the animals. Table 1, on page 219, shows the pasture composition from one property where greying occurs and shows also the copper contents of livers and of blood samples taken from a random selection of animals on that property. It will be seen • that the pasture is much higher than normal in molybdenum and that the livers and some of the blood samples are much lower than normal in copper content. Method of Supplying Copper The greying and unthriftiness can be prevented by increasing the copper supplies of the cattle, but the way to do this economically was at first , something of an enigma. Topdressing the pasture; with copper salts would have been satisfactory except. for the cost. Both sheep and cattle are carried on affected farms, but the sheep do not need extra copper and any financial return for the outlay on topdressing would come only from improvement in the cattle. As might be expected, sheep are in the majority and cattle are carried in low concentrations. For instance, on one farm of 300 acres there are 200 breeding cows, and it is the progeny of these 200 cows

that would have to return the full cost of topdressing. The cost per animal that could be benefited would therefore be uneconomically high. Licks could supply the necessary copper, but would also be expensive and would have to be put out in such a way that they were inaccessible to sheep, because a lick with sufficient copper to benefit the cattle would be dangerous for sheep. Since neither topdressing of pastures nor provision of licks was likely to prove suitable, the possibility of con-

trol by direct treatment of animals was considered. Effective and cheap control of the disease was finally achieved by supplying, copper through the injection of copper compounds. After a number of trials, which ranged from intravenous injection of bluestone to subcutaneous placing of copper wire, the form of copper finally used was a compound known as copper glycinate, which is a blue powder containing 30 per cent, of copper. For injection into cattle the powder is suspended in a mixture of neat’s-foot oil and marrow fat or of beeswax in

peanut oil and the suspension, known as copper glycinate cerate, is dispensed in small; collapsible, single-dose tubes holding about- 1 c.c. The tube and its contents can be sterilised by heat when first filled and stored in this sterile state, until required for use. The dose is administered by squeezing it through a hypodermic needle placed to deliver either subcutaneously or intramuscularly. Dose A suitable dose of copper glycinate was decided on in the following way: Measurements were first; made of the proportion of the injected copper which reaches the liver. From this information, a dose was selected which would deposit in the liver about the same amount of copper as is found in normal animals. Finally the selected dose was tried in the field to learn whether it would protect susceptible animals against greying. To measure what proportion of the dose of copper gets into the liver it is necessary to know the weight of the liver and the concentration of copper in the liver before dosing and several

weeks alter ward. The weight of the liver can be measured after slaughtering the animal at the end of an experiment or can be calculated with sufficient accuracy from the body-weight. The concentration of copper in the liver can be measured at any time by analysing small pieces removed

surgically. Using t h es e methods it was found that 400 mg. of copper glycinate is a satisfactory dose for cattle. This dose of glycinate contains 120 mg. of copper and of this about 100 mg. reaches the liver 2 to 4 weeks after dosing. That quan-

tity will raise the N concentration of copper by about 100 parts per million of dry liver and bring the level to that found in normal, healthy animals. For tests on the control of greying made under practical farming conditions 400 mg. of copper glycinate was the dose finally decided on. Times of Dosing The times at which doses should be administered had also to be decided. Access to run calves is governed to a large extent by the problem of mustering, but there are at least two essential musters on any station, one for marking and one for weaning. The suitability of these two muster periods for preventive injections was therefore studied by treating some animals and comparing their progress with that of untreated animals in the same herd. This comparison in the same herd was made possible by treating heifer calves and leaving steers untreated. The effectiveness of a treatment was meas- , ured by its success in bringing animals through to 15 months of age in a thrifty condition without greying of the coat. It was found that young calves, 2 to 3 months old, could safely be injected

with 400 mg. of the cerate at marking time in November. By the next (weaning) muster in the following May treated animals were found to be in better condition than the untreated ones. In some years there were a few treated heifers showing grey round the eyes and in other years some even showed a mottled coat, but stunted and severely greyed animals did not occur. Among untreated steers on the other hand there were in some years as many as 25 per cent, which showed severe greying at weaning. Results of Treatment Blood-copper examinations were made on treated heifers and untreated steers and typical results are shown in Table 2. In some cases the blood

copper of heifers was as low as that of steers at weaning time. This indicated that the dosing rate was borderline and suggested that an additional dose of cerate between marking and weaning would have been an advantage. In the several years of observations heifers treated at marking were

in good condition at weaning despite low blood copper, and there was therefore no justification for the expense of an extra muster between marking and weaning. A second dose to the heifers given at the weaning muster in May enabled the heifers to maintain an advantage over untreated steers in coat colour and general thrift until the following November. After this further cases of greying do not develop, even if no treatment has been given. An example of the advantage to treated heifers over untreated steers is the comparison made in August 1955, 3 months after the weaning treatment in May. By this time the heifers had had two treatments and the steers none. In 90 heifers there was one showing moderate greying and 9 with slight greying; in 92 steers there were 21 with marked greying and 22 with slight greying. The slight tendency in some heifers to greying between the third and sixth months after the weaning dose of copper could be prevented by administration of a third dose at a special muster of weaners made 3 months after weaning. Such a muster is less difficult than one involving cows and calves together and is considered worth carrying out to obtain the

The black areas are the soils, listed in Table 3. where high-molyb-denum pastures occur.

advantage of the extra dose of copper. Table 2 shows the definite superiority in blood copper of treated heifers over untreated y steers 3 months and 6 months after weaning. It also shows the further advantage derived from a third dose of cerate given 3 months after weaning. The experimental work carried out on copper glycinate cerates has shown that they are effective for control of the greying and unthriftiness described. The treatment is three injectionsone at marking, one at weaning, and one 3 months after weaning. Usually further treatment of older animals will be unnecessary, but if greying and loss of condition in cows do occur, copper can be supplied by the same injection method. Because of variation between years and farms, it is not possible to lay down any rule for treatment of adult animals. A cerate should be injected if there are signs of greying ox- loss of condition. Injection Procedure Injection in the beef animal is best made subcutaneously. With intra-

muscular injection there is a risk that an abscess could form and remain undetected right up to the time of use of the meat. Even though such abscesses are very rare, the risk of loss of the prestige of the meat is one that should be avoided. Slight blemishes are sometimes left after subcutaneous injection, but these are less important, for they can be seen and trimmed off. On farms where blackleg occurs there is a slight risk that an injection could carry spores of blackleg with dust from the skin and cause blackleg in the calf. Where blackleg has been known to occur injections should not be made unless calves have been vaccinated at least 2 weeks previously with blackleg vaccine. Copper cerates have also proved to be convenient and suitable for sheep. The dose for sheep, arrived at in the same way as for cattle, is 150 mg. of copper glycinate, which provides 45 mg. of copper. With this dose the concentration of copper in a sheep’s liver is increased by about 300 parts per million, which ensures enough copper for at least 12 months, even if the sheep is . living on a diet which is very deficient in copper. Sheep are susceptible to poisoning by copper, and a cerate containing a cattle dose could poison a small sheep. Since copper cerates are a satisfactory source of copper for both cattle and sheep, they can be used as an alternative to other methods for controlling copper deficiency. Their special value is for treatment of animals on areas where conventional methods of supplying copper are too expensive. The instance of molyb-denum-rich pastures has been discussed in this article. Where Disease May Occur There are fairly .large areas in New Zealand which produce pastures high in molybdenum and a list of the soils on which they grow is given in Table 3 with the approximate area of each soil where this is known. Disease in cattle controllable by supplying copper has been diagnosed on farms situated on those soils marked by an asterisk. The symptoms vary for different soils. For example, on . peat soils the whole herd may fie affected with, acute spring scouring, while on Tuai coarse sand between Wairoa and Lake Waikaremoana the main problem is the greying of weaners already described. The similarity of the chemical composition of pastures from the soils listed in Table 3 suggests the strong possibility that disease controllable by supplying copper could occur, on any farm situated on any one of the soils. It is, indeed, likely that such diseases already occur but ' have been overlooked because they might not recur every, year and because the unthriftiness, the greying, or the scouring have not been recognised as signs of a disease.

The situation now is changed. It is known that when these signs occur in cattle it is probable that they are caused by too much molybdenum and too little copper in the fodder, and that probability is very high indeed if the cattle are kept on any of the soils named. It is advisable therefore for farmers on these soils to keep this probability in . mind when inspecting their stock. Copper cerates are effective and economical for treatment of single animals or whole herds.

The locations of the North Island soils in Table 3 are shown as black areas on the map on page 221. No map of the South Island soils is yet available, so these cannot be shown in the same way. The map is not on a big enough scale to show whether any particular farm is situated on one of the soils, but it does allow some estimate of that possibility to be made. A talk with the Instructor in Agriculture for the district will settle the question.

Pasture: Affected areas Normal Copper contents (parts per million in dry Affeeted areas Normal Copper contents (parts per million in dry 7.3 pasture) 7.0 10.0 Molybdenum content (parts per million 17.5 in dry pasture) 19.6 1.5 Liver: Copper contents (parts per million5.0 (adult steer) liver) 7.7 (adult cow) » ' Copper contents (parts per millionin dry 5.0 liver) 7.7 in dry (adult steer) (adult cow) 150 150 11.9 (adult steer) (adult steer) Blood: [ Average 0.04 (45 animals 7-9 months < old) 0.09 Copper content (milligrams per 100 mill!1 Range 0.016-0.064 ■— litres of blood) [ Average 0.05 (36 animals 12-15 months t old) 0.09 1 Range 0.030-0. —

3 6 months months after 6 months after weanWeaning Ing ing Mg. per 100 ml. 100 ml. of blood 1955: \ weaning of blood .■Heifers treated at marking and weaning 0.052 Steers untreated 0.040 1956: Heifers treated at marking and weaning only 0.039 0.083 0.065 Helfers treated at marking, weaning, and 3 months after 0.039 0.085 0.083 Steers untreated 0.048 0.055 0.050

TABLE b—AVERAGE BLOOD COPPER IN TREATED HEIFERS AND UNTREATED STEERS.

Average content Approximate area acres Copper parts per Molybdenum million NORTH ISLAND SLAND ♦Rotomahana sandy loam 8.0 6.5 4,500 *Peat soils .. .. .6.9 11.7 300,000 Tukituki set . .. .. .. .. 10.4 5.2 93,000 ♦Opiki complex .. .. .. .. . .. 11.8 5.5 17,000 *Konoti clay loam, hill soils .. .. 8.5 5.7 23,000 *Tuai coarse sands .. 8.0 7.8 200,000 *Tihoi-Opa complex •. 4 ■ ' .. . 7.1 .■ 6.1 *Tihoi sand .. .. .. .. ■'.... .. 5.1 4.6 f Maramaru coarse sands .. . .. 8.0 5.5 10,000 Taumarunui sandy silt, hill soils .. .. 10.7. 8.0 8,000 Matawai sandy loam .. .. .: .. .. .. 9.5 8.3 19,000 ♦Ahuriri soils .. .. .... .. .. .. 8.0 7.9 8,000 Waihua stony sandy loam .. .. 7.9 8.7 78,000 SOUTH ISLAND . *Motukarara sandy loam, weakly saline phase .. 7.0 8.0 Omihi silt loam .. .. ■ .. .. .. .. 6.8 4.4 ♦Weka sandy loam , .. • .. .. .. .. 3.9 ■ 4.5 * Disease in cattle controllable by supplying copper diagnosed on farms on copper diagnosed on farms on these soils. these soils,

TABLE 3—COPPER AND MOLYBDENUM CONTENT OF SOILS WHICH PRODUCE PASTURES HIGH IN MOLYBDENUM