Evaluating the economics of short-term partial mixed ration feeding decisions for dairy cows

Abstract

Recent research in Australia has measured the marginal milk production responses of cows grazing perennial-based pastures to supplements offered as a partial mixed ration (PMR). In the present study, the milk responses to PMR feeding developed under a restricted pasture allowance were used to examine the contribution to farm profit of decisions about short-term feeding (weekly, monthly). A short-term, or tactical, decision was considered to be one where the infrastructure and equipment needed to mix and feed out a formulated ration were already available. The decision was, therefore, the choice of whether to feed supplements as grain in the dairy at milking and forage in the paddock, or to feed the supplements as a mixed ration on a feed pad. Both of these options were assumed to exist for the farmer decision-maker, with the comparison of rations being based solely on the costs of supplement and milk income. The Control diet in the experiments comprised cereal grain fed in the dairy and pasture silage fed in the paddock, simulating a situation where pasture available for grazing was limiting. The PMR diet consisted of cereal grain, maize grain, maize silage and lucerne hay combined in a mixer wagon and fed on a feed pad. The PMR + canola diet was similar to the PMR diet, but included canola meal. The profitability of the diets for different amounts of supplement intake was compared by estimating the total income from milk produced minus the cost of the supplements. The results indicated that feeding the diet comprising PMR plus canola meal in early lactation contributed more to farm profit than did the Control diet of feeding grain in the dairy and forage in the paddock, or PMR feeding without canola meal, because of higher milk production. At a supplement intake of 12 kg DM/cow.day, the PMR + canola diet added AU$0.97/cow.day and AU$2.11/cow.day more to profit than the Control and PMR without canola meal diets, respectively. For a farm already equipped with a feed pad and mixer wagon, the benefits of feeding a mixed ration exceed the costs in early lactation. In late lactation, each diet made similar contributions to farm profit because of similar milk production.