Abstract:
6A THE EFFECT OF MONENSIN IN DAIRY COW RATIONS ON MILK PRODUCTION AND IN REDUCING THE SEVERITY OF SUBCLINICAL KETOSIS B.C. Granzin*, K.J. Gunn**, L.B. Lowe*** and L.K. Wade*** Sub clinical ketosis in lactating dairy cows is characterised by a fall in plasma glucose levels, an increase in plasma ketone levels, and a drop in milk production (Schultz 1968). Van Maanen et al. (1978) observed that monensin, an ionophore, increases net glucose production and absorption in steers. Therefore supplementing dairy cows in early lactation with monensin could reduce the effects of subclinical ketosis. Twenty-four Holstein Friesian cows ranging from first to sixth lactation were allocated to four different treatments in a randomised complete block design. Treatments were 0 (control), 150 (Tl), 300 (T2) and 450 (T3) mg monensin per day. Treatments were offered in a 1 kg supplement from two weeks pre partum to twelve weeks post partum. Plasma glucose, bhydroxybuytrate and milk production were recorded during this period. TABLE 1 Plasma levels of glucose, p-hydroxybutyrate and daily milk production recorded during the treatment period As shown in Table 1, although there were no significant differences in glucose or k hydroxybutyrate concentrations in plasma, there were significant increases in daily milk production. The improvement in milk production shown in this trial requires further investigation. Schultz, L.H. (1968). Journal of Dairy Science 51:1133. Van Maanen, R.W., Herbein, J.H., McGilliard, A.D. and Young J.W. (1978). Journal of Nutition 108:1002. . * Department of Animal Production, University of Queensland Gatton College, Lawes, Qld. 4343. ** Department of Agriculture, University of Queensland St Lucia, Qld. 4067. *** Elanco Animal Health, West Ryde, N.S.W. 2114.
