Abstract:
Proc. Aust. Soc. Anim. Prod. (1978) 12: 173 SUPPLEMENTS OF MOLASSES, BARLEY OR PASTURE HAY FOR DAIRY COWS RESTRICTED IN ROUGHAGE INTAKE B.D. BARTSCH* and R.B. WICKES* During periods of poor pasture growth in southern Australia, the price of hay, relative to molasses or grain, may increase such that molasses or grain may be a more economic energy source for milking dairy cows. This paper compares molasses, barley grain and pasture hay as alternative energy supplements to maintain the production and live weight of dairy cows restricted in roughage intake. After an-initial 1 week covariance period, forty two Friesian cows with a mean live weight of 550 kg were divided into six groups and fed 70% of their metabolizable energy (ME) requirements from an annual ryegrass-clover hay. Additional ME was supplied to two groups as either molasses or rolled barley fed at 10% of ME requirements and to three groups as either molasses, rolled barley or annual ryegrassclover hay fed at 30% of ME requirements. The sixth group received no additional ME. These rations were fed for 6 weeks. During the covariance and final 4 weeks of the experiment, daily milk yields were measured and milk samples analysed for fat, solids-not-fat (SNF) and protein content. Cows were weighed three times weekly. Mean covariance corrected milk and milk component yields and mean daily live-' weight changes over the final 4 weeks of the experiment are presented in Table 1. TABLE 1: Mean daily yields of milk and milk components and mean daily liveweight changes of cows The ME of rolled barley was used more efficiently than that of molasses or hay for milk, SNF and protein production when these supplements were fed to meet the ME requirements of the cows. The cost of molasses or hay per MJ of ME must be lower than that of barley before molasses or hay can be economically justified as supplements for maintaining the milk production of cows on a restricted intake of hay. *Northfield Research Centre, Department of Agriculture and Fish,eries, Box 1671, G.P.O. Adelaide. South Australia. 5001 173. .
