Abstract:
The major thrust of the AMl-RDC sponsored Northern Australia Programme lift productivity of current breeding herds 20 % by H94. A key component in this strategy is to optimise phosphorus intake by direct animal supple~tation ; and frequently fertiliser grade mo - ammonium phosphate (NW) is the most cost effective choice. Traditionally this is offered in a Mfortunately,acceptance is often variable md variety of dry,loose mixes. frequently intake is lowest during the summer months when growth ptential is at a maximum. is to phosphric acid (CPA) However,results w i t h to water is cantrolled,water medication based on c&c dispensers has provided an alternative approach, this technique have hem less than consistent and ,in recorded in sane instances,serious health problems and/or deaths have been supplemented cattle (cf. review by Winks,1988)~ Where access The more recent development of reliable and fail-safe,dry gt-anu.le dispensers - ideally suited to Mcsp based mixtures - has rekindled industry interest in this approach. Accordingly,we are examining various facets of compulsory supplementatiw, with MAP in water, Thusfar seasonal conditions have prevented IJS from quantifying me of our prime objectives ie voluntary water intake on MAP supp1eWnted waters 8 significant observatims have been made. In the first instame t+a+ever Y tm l%F is used because of its price,ease of handling and claimed scAubility. two sites have raised doubts as to the practical Repeated measurmts at accuracy of this last assumption. water ' lockti up' for 12 to 15 lmurs than 95 % of the targeted P ccncentration (0.31 g LoA), c017tained b e t t e r However,initiation of the dispense/dissolution process either by c,attle drinkinq or by manual mptying gave disappointing results. Two hours afterthe refilling process began,water still contained C 0.19 g P tBL : and this The implications for &middle and occurred at water temperatures > 28 %. tail of the mob are obvious. Animals failing to share the stood-over water would at best get 50 to 60 % of the targeted P dose. This may help explain sag of the highly variable resu1ts obtained even with P medicated water systems 8 potentially threatening observation concerned cadmium A second a n d (Cd) levels in MAP treated water. W both sites,the Cd concentration of the treated water was markedly in excess of the maximum recommen ded level (O.Wi:~ mg cd rz for livestock. Obviously these levels will be influenced by numerous factors - not least the high Cd cantent of currently available fW situation will be discussed. Winks&. sources Raymen t I pers cm) l The implications and management of this 1988) Working paper for the AMLRDC Workshop on Phosphorus in Beef Froductiw, in Northern Australia,TowsviIle,June,198& ~---~---~-~C----------~------------------------------------ 1 Departmt of PCwry Industries , Clninal Research Institute 1 Ymcmgpilly I I)Li) I 4105 2 Departmt of Priaary Industries 9 PU Box 147 9 Barcaldine I QLD 9 4725 3 Department of Priwy Industries 9 PU 60x 538 g hen QLD s 4805 I 14A