Vitamin D and anthelmintic treatment improve growth rates of young sheep in the Falkland Islands

Abstract

Animal Production in Australia 1998 Vol. 22 VITAMIN D AND ANTHELMINTIC TREATMENT IMPROVE GROWTH RATES OF YOUNG SHEEP IN THE FALKLAND ISLANDS S.M. MILLERA, C.S. LAMBA, M.P. REICHELAB, P. McCABEAC and D. BABER Dept of Present C Present D Present A B AD Agriculture, Stanley, Falkland Islands Address: MAF, Upper Hutt, New Zealand Address: Renfrewshire, United Kingdom Address: Worthing, Sussex, United Kingdom Nutritional deficiencies have previously been detected in Falkland Islands sheep, and supplements of cobalt (Co) and selenium (Se) are beneficial in some regions (Whitley 1979). Fragile bones occur periodically in young sheep and it is thought that poor calcium (Ca) absorption may limit growth and development. In addition, the low altitude of the sun in the Falklands (latitude 51 to 53o south) may restrict vitamin D synthesis in the skin of sheep during the austral winter. In order to examine the effects of improved Ca metabolism on the growth of young sheep, this experiment evaluated vitamin D supplementation and anthelmintic treatments during the period between weaning and first shearing. Ewe (n=125) and wether lambs (n=125) were randomly allocated to five treatment groups for each sex (n=25) immediately after weaning. Treatments commenced immediately and were; (i) untreated, (ii) oral anthelmintic (Panacur), (iii) anthelmintic containing Se and Co (Panacur SC), (iv) vitamin D3 injection, and (v) anthelmintic (Panacur) plus vitamin D3. The sheep were run together as one mob and grazed native pasture from January until November. Liveweight was recorded in January, April, June, September and November. Anthelmintic and vitamin treatments were administered in January, April, and June. The anthelmintic was also administered in September. Table 1. Liveweight changes (LWC) between Januar y and November for weaner ewes and wethers supplemented with vitamin D or treated with an oral anthelmintic with or without selenium, cobalt and vitamin D Control LWC Ewes (kg) LWC Wethers (kg) 4.1 2.6 a a Vitamin D 5.1 5.1 ab b Anthelmintic alone 4.9 4.0 ab ab Anthelmintic plus Se and Co 4.9 4.4 ab ab Anthelmintic plus vitamin D 5.5 5.0 b b s.e.m. 0.41 0.77 Values within rows followed by different letters are significantly different at P = 0.05 Administration of vitamin D significantly improved liveweight gain of wethers for the experimental period. Ca concentrations in Falkland Islands grasses are low (Davies 1988), and blood Ca levels of weaner sheep may fall below the normal range (Miller et al. 1998). Supplementing sheep with vitamin D may augment poor in situ synthesis of the vitamin, enhance absorption of the Ca consumed, and promote liveweight gains. Anthelmintic treatment alone did not significantly enhance liveweight; however, as the anthelmintic-treated sheep were run with untreated sheep, cyclical re-infection with internal parasites was likely and the benefits of the anthelmintic may have been short-lived. Nevertheless, treatment with anthelmintic in addition to vitamin D supplementation significantly improved liveweight gain for both ewes and wethers. Blood Ca levels for vitamin D supplemented sheep were not significantly different from those of unsupplemented sheep throughout the experimental period (data not shown), thus further research is required to evaluate the extent to which Ca metabolism limits production. We thank the owners of South Harbour farm for providing facilities and generous assistance during the conduct of this experiment, and the Queens University of Belfast for biometric services. DAVIES, A.B. (1988). End of Contract Report. (Overseas Development Administration: London). MILLER, S.M., LAMB, C.S., REICHEL, M.P., McCABE, P. and BABER, D. (1998). Anim. Prod. Aust. 22, 000. WHITLEY, R.S. (1979). Report of the Grasslands Trials Unit 1975 - 1979. Appendix 4 & 5. (Grasslands Trials Unit: Stanley). 395