Abstract:
Animal Production in Australia UTILIZATION OF MAIZE SILAGE-BASED DIETS BY DAIRY COWS AND SHEEP C. LEMERLE*, J.B. MORAN* and T.E. TRIGG* Silages are receiving attention as an alternative to grazed pastures for livestock in the irrigation area of Northern Victoria, partly due to the large amount of dry matter (DM) per hectare that can be produced from forage crops such A study was carried out to compare the utilization of as maize and sorghum. silage-based diets by three classes of livestock, i.e., lactating cows, dry cows and wether sheep. Eighteen animals (six per livestock class) in metabolism cages were offered three diets supplemented with urea (1.3%) and minerals (l.O%), viz. maize silage (MS) alone; MS plus lucerne (33%); MS plus lucerne (15%) plus wheat (50%). Feed DM intake (VFI), water intake, urine output, and diet DM digestibility were Preliminary results are shown in Fig. 1. measured. FIGURE 1 Digestibility and intake of maize silage-based diets by lactating cows, dry cows and sheep DMD (%) DM digestibility (DMD) of MS alone was similar for lactating cows (60%), dry cows (63%) and sheep (6378, whereas VFI was greater in the lactating cows Addition of lucerne to the (53 g/kg OS') than in the other animals (44 g/kg''). diet improved diet digestibility in the sheep (DMD; 67%) and also stimulated VFI MS plus lucerne plus wheat increased the in the lactating cows (70 g/kg''). digestibility of the diet in all classes of livestock; lactating cows (69%), This was accompanied by a decrease in VFI in the sheep (72%), dry cows (75%). sheep (43 g/kg'' > and dry cows (34 g/kg'' > whereas the lactating cows mainConrad et al. tained the same VFI (70 g/kg'*' > as on the MS plus lucerne diet. (1964) found a similar decline in VFI once the digestibility of the diet was greater than 64x, but noted that the critical DMD value above which VFI declined depended on the caloric density of the diet and the productive status of the animal. The intake of digestible DM in the lactating cows increased with dietary quality, but this was not associated with corresponding increases in milk yield. There was no marked intake response in the sheep and dry cows when they were offered the better quality diets. CONRAD, H.R., PRATT, A.D. and HIBBS, J.W. (1964). J. Dairy Sci. 47:54. * Department of Agriculture, Animal and Irrigated Pastures Research Institute, R.M.B. 3010, Kyabram, Vic. 3620. 624
