Economics of Feeding Concentrates at Grass

Grazed grass forms a major part of spring and summer diets for dairy cows in Northern Ireland. However grass alone will not always meet the needs of these animals. In order to maximise the economic response to concentrate feeding, it is important to develop a strategy that maximises responses to supplementation while minimising reductions in grass intakes. The following article will highlight factors which affect this strategy.

Supplements should be fed in situations where grass energy intakes are unable to meet the needs of the cow. Situations under which the best responses to concentrate feeding are obtained are as follows:

Cows yielding in excess of 25 l/cow/day will require supplementation in order to minimise loss in condition and maintain herd fertility. It may be argued that this approach could be costly under poor milk prices. However it should be borne in mind that cows which are underfed in early season will produce less milk during the summer and into the autumn at a stage when milk prices are increasing and that the current cost of leasing or buying milk quota is low compared to previous years. In addition responses to concentrate feeding increase as milk production rises. The figures in Table 1 give suggested levels of feeding for cows grazing well managed pastures over a range of milk yields. It should be noted that the recommendations will change according to the quality of grass available and grass dry matter (DM) intakes which are achieved.

Table 1. Supplementary concentrate levels for high yielding cows

Assumes milk price @ 16 ppl, grass cash cost @ £39/t DM and concentrate @ £150/t

Grazed grass can potentially supply up to 27 l/ cow/ day in mid may. However in order to realise this potential, cows must graze around 18 KG DM/ cow/ day (approximately 100 KG fresh grass/ cow/ day). Under cold, wet conditions or situations where grass supply is limited, it will be difficult to achieve these intake targets. Cows grazing under these conditions should receive additional supplementation above their normal allocation.

Concentrates based on digestible fibre ingredients have been shown to minimise reductions in grass intakes and enhance butterfat production. Examples of ingredients containing digestible fibre include sugar beet pulp, citrus pulp and soya hulls.

An effective concentrate feeding strategy at grass should target supplements to high yielding cows and animals grazing under difficult grazing conditions. Concentrate feeding at grass is one of the topics that is addressed in the Grass Challenge. Contact your local Dairying Development Adviser to discuss how participating in the Grass Challenge can help to identify the grazing management programme that best meets the need of your farm.

Samuel Hill, Randalstown (right) discusses his concentrate feeding proposals for this grazing season with Aidan Cushnahan (CAFRE).