Investigations on the effect of copper, cobalt and phosphorus on the growth of grazing Hereford cattle in coastal New South Wales.

Abstract

INVESTIGATIONS ON THE EFFECT OF COPPER, COBALT AND PHOSPHORUS ON THE GROWTH OF GRAZING HEREFORD CATTLE IN COASTAL NEW SOUTH WALES H. LLOYD DAVIES* and M. CHANDRASEKARAN* SUMMARY Twenty Hereford cows and twenty heifers grazing narrow-leafed carpet grass (Axonopus affinis Chase) dominant pastures in central coastal New South Wales were divided into five groups: control, copper glycinate injected monthly, copper glycinate injected bimonthly, copper (Cu) monthly plus phosphate supplement, copper bimonthly plus phosphate supplement. Four of the eight females in each group were given a cobalt (Co) 'bullet'. The experiment ran from February 1976 to December 1977. Administration of Cu bimonthly increased mean liver Cu from the control value of 8.5 mg/kg/DM to 36.2 mg/kg (P<O.OOl). Monthly injections raised liver Cu to 72.0 mg/kg (PCO.001). There was no significant effect upon live weight from Cu, phosphorus (P) or Co supplementation. INTRODUCTION Unsatisfactory growth rate and reproduction in beef cattle on the central and north coastal areas of New South Wales are frequently reported by producers and extension workers. There is ample evidence that liver and blood Cu values of cattle in coastal New South Wales are often low (Lloyd Davies 1977). Liver Cu values of less than 10 mg/kg and plasma Cu values of less than 3 ug/ml often occur. Both P deficiency (Cohen 1976) and Co deficiency (Alexander, Harvey, Lee and Stubbs 1967) have been demonstrated in the east coast. An experiment was conducted to investigate the role of Co, Cu and P in production of cattle grazing initially (February 1976 to January 1977) on the A.M.P. property at Tea Gardens, N.S.W. and from January 1977 to December 1977 at 'Burraduc' Station, Bulahdelah, N.S.W. MATERIALS AND METHODS were born had teen There were 20 cows and 20 heifers of the polled Hereford breed. The cows of mixed ages ranging from 3 years to 6 years. Sixteen of the heifers were in late 1973 and four in late 1974. When the experiment started the cattle been joined in November 1975 to,polled Hereford bulls and subsequently sixcows and eight heifers calved. Twenty-nine cattle calved in 1977. The cattle were divided into the following treatments with four cows and four heifers in each group: 1, Controlg 2, Cu given as copper glycinate (400 mg Cu) monthly, 3, Cu given as copper glycinate intramuscularly bimonthly; 4, Cu given as copper glycinate intramuscularly monthly,and for the first 13 months of the experiment the cattle were each dosed monthly with 300 ml of a saturated solution of sodium dihydrogen phosphate. Later (from February 1977) the phosphate was given in a very dilute solution of molasses in a roller-licker drum such that the cattle received approximately 10 g of P per animal per day; 5, Identical P treatment to 4 but the copper glycinate was injected bimonthly. Two cows and two heifers in each group were given a Co 'bullet' (cattle size) and a grinder at the start of the experiment. * School of Wool and Pastoral Sciences, The University of New south *Kensington, N.S.W. 2033. . Animal production in Australia Up to January 1977 all cattle wererunin one paddock at Tea Gardens. From February 1977 until December 1977 the cattle were run at 'Burraduc'. Here the cattle in groups 4 and 5 received their phosphate in a dilute molasses solution using a roller-licker drum and were run in a separate paddock from the nonphosphate group. Visual examination showed similar botanical composition of the paddocks but no claim is made that the paddocks involved 'were identical. Both groups were run at a low stocking rate (approximately 1 cow per 2 hectares) and feed on offer was never limiting \in quantity. Jugular blood samples from all cattle were taken at approximately threemonth intervals. Plasma samples were analysed for ceruloplasmin by the method of Bingley and Dick (1969) and plasma Cu determined by Bingley and Anderson (1972) regression equations. Plasma Cu determinations, as a check on the ceruloplasmin values were carried out on 7 random samples. Agreement between determined Cu values and derived Cu by regression from ceruloplasmin values was excellent. Inorganic P of the plasma was determined by the method of Fogg and Wilkinson (1958). Liver samples from most of the cattle were obtained by biopsy in the second year of the experiment for Cu determination by the technique of Eden and Green (1940). All liver Cu values are expressed on a dry matter basis. RESULTS AND DISCUSSION Liver copper levels Liver Cu values taken 20 months after the start of the experiment were: controls, 8.6 mg/kg/DM (SE=0.99); Cu bimonthly, 36>\2 mg/kg/DM (SE=4.8); Cu These differenceswere all highly significant monthly, 72.0 mg/kg/DM (SE=9.7). (P<O.OOl). These liver Cu values clearly illustrate the following features, (4 The very low (8.6 mg/kg) value for the untreated cattle. These figures would be accepted as indicative of clinical Cu deficiency e.g. Underwood (1977) who stated that the normal value for cattle was 100 mg of Cu per kg of liver dry matter. Liver copper concentrations were increased to 36 mg/kg and 72 mg/kg in animals injected with Cu at bimonthly and monthly intervals respectively. This suggests that Cu administration bimonthly will not bring levels of liver Cu to that achieved by monthly injection. Plasma copper content (W Plasma Cu values in relation to time are shown in Fig. 1. At Tea Gardens plasma levels were low then gradually rose following administration of Cu. The control values remained low until November 1976 when they rose and remained high on all subsequent sampling times. The plasma Cu levels were different (PxO.05) at the first four samplings compared with the later sampling times. The effect of Cu supplementation on plasma Cu values was significant (P<O.O5), only on the November 30, 1976 samplings but the trends were in the expected direction on the April and August 1976 samplings. When the cattle were transferred from Tea Gardens to 'Burraduc' the pastures at the two properties appeared similar. However, there was an immediati rise in levels of plasma Cu in all cattle and thereafter the levels remained high. Apparently low liver Cu levels are not necessarily reflected in low plasma Cu. Low levels of plasma Cu are usually associated with low levels of liver Cu. 218 Animal production in Australia Live Weights Live This table heifer was figures for weights of the animals in relation to treatment are shown in Table 1. shows relatively low absolute weights for mixed age (the youngest at least two) Hereford females and low liveweight gain compared with similar cattle on clover-based pastures. 'Table 1 Live weight (kg) of cattle in relation to copper, phosphorus and cobalt Effect of cobalt Co had no effect on liveweight change. 219 A~nimal production in Australia Effect of phosphate There was no evidence of a response in live weight to P supplementation. The plasma inorganic P concentration (mg/lOO ml) of the control animals was 6.18 (SE=0.66) and of the P supplemented group 7.28 (SE=0.68). The value of the control animals was within the normal range. Effect of copper With the very low levels of liver Cu (and initially plasma Cu) a response in live weight would have been expected. This did not happen. Although responses to Cu administration have been obtained in cattle when the Cu deficiency is induced by a high level of molybdenum (MO), there are few times that a response in live weight in grazing cattle has been obtained from Cu supplementation to uncomplicated Cu deficiency. There have been cases reported in Queensland, e.g. Hewetson and Bremner (1962) and Alexander, Harvey, Lee and Stubbs (1967) of responses in weaner gain and in conception rate, when MO excess has not been involved. The results of this experiment show that in cattle grazed at a very low stocking rate (approximately one cow per two hectares), a problem of poor growth (Table 1) exists in cattle grazing coastal pastures in New South Wales. This preliminary investigation indicated that there was no response in production from the injection of copper despite the initial levels of both liver and plasma Cu being clinically low. The Cu administration was sufficient to correct both storage and circulating levels of Cu but this was not reflected in improved liveweight gain. This work also showed no response in live weight to cobalt or to phosphorus. There may be other mineral deficiencies which must be rectified before a response to Cu, Co or P is obtained but at present there are no indications of which other elements are limiting on pastures of coastal New South Wales. ACKNOWLEDGEMENTS The whole of this project was funded by the Australian Committee. Research Merck, Sharp,& Dohme (Aust.) Pty. Ltd., donated 'Thiabenzole', the antihelmintic used in this work. REFERENCES ,% J. Aaric AIEXANDER, C. I., HARVEY J-M., LEE, H.H. and STUBBS, W.C. (1967). Res. 18: 169. BINGIZ~J.E and DICK, A.T. (1969). Clin. Chim. Acta. 25: 480 BINGLEY, J.B. and ANDERSON, N. (1972). A$. 2: 8185. COHEN, R.D.H. (1976). Proc. Aust. Soc. Anim. Prod. 11: 253. DAVIES, H, LLOYD (1977). Aust. J. Exp. Agric. and Anim. Husb. 17 : 905 EDEN, A. and GREEN, H.H. (1940). The Biochem. J. 34: 1202. FOGG, D.N. and WILKINSON, N.T. (1958). The Analyst 83: 406. HEWETSON, R'.W. and BREMNER, K.C. (1962). Aust. Vet. r 38: 590. UNDERWOOD, E.J. (1977). 'Trace Elements in Human and Animal Nutr 'i tion : . (Academi ,C Press: New York.). 220