In one experiment twenty‐four Holstein Friesian cows, average 43 d post‐partum, were used in a changeover design experiment to evaluate the replacement of a cereal‐based concentrate supplement (C) by an ensiled mixture (MGBP) of malt distillers’ grains and molassed sugar beet pellets. The cows were offered grass silage ad libitum [dry matter (DM) content 170 g kg−1, crude protein (CP) concentration 160 g kg DM−1, metabolizable energy (ME) concentration 10·9 MJ kg DM−1] and either C or MGBP at one of three levels (3, 6, 9 kg DM d−1). The composition of C and MGBP were DM content: 853 and 296 g kg−1, CP concentration: 202 and 187 g kg DM−1, ME concentration: 12·6 and 10·8 MJ kg DM−1 respectively. The cows ate all the C supplement but the intakes of MGBP were 2·7, 4·9 and 6·4 kg DM d−1 for the 3, 6 and 9 kg DM d−1 levels of MGBP respectively. Total DM intakes (kg d−1) were 12·5, 15·6, 18·2 for treatments 3‐C, 6‐C and 9‐C and 13·1, 14·4 and 15·9 (s.e., 0·90) for treatments 3‐MGBP, 6‐MGBP and 9‐MGBP respectively. Milk yields (kg d−1) for treatments 3‐C, 6‐C and 9‐C were 19·9, 23·2 and 24·2, respectively, and for treatments 3‐MGBP, 6‐MGBP and 9‐MGBP were, 20·3, 21·3 and 23·0 respectively (s.e., 1·05). Milk fat contents (g kg−1) for treatments 3‐C, 6‐C and 9‐C were 42·8, 42·3, 43·5 respectively and for treatments 3‐MGBP, 6‐MGBP and 9‐MGBP were 39·5, 38·7 and 38·2 (s.e, 1·86), respectively, and milk protein contents (g kg−1) for treatments 3‐C, 6‐C and 9‐C were 30·5, 30·6, 31·8, respectively, and for 3‐MGBP, 6‐MGBP and 9‐MGBP were 30·0, 30·8 and 31·2 (s.e., 0·66) respectively. Milk yield and milk protein contents were significantly higher for the higher levels of supplementary feeding but there was no difference between the types of supplement. The milk fat contents were significantly lower on the MGBP than C supplements. In a second experiment fifteen Holstein Friesian cows, average 126 d post‐partum, were used in a changeover experiment to evaluate the replacement of all (treatment M) or half (treatment MS) of the grass silage (S) in their diet by a mixture of MGBP and straw. All cows received 5·1 kg DM d−1 of concentrate feed. Forage DM intakes were 8·3, 11·2 and 14·2 kg DM d−1 for the S, MS and M treatments respectively. Milk yields (kg d−1) for S, MS and M treatments were 17·0, 19·4 and 20·0 (s.e., 0·56) respectively. Corresponding contents of milk fat and protein (g kg−1) were 42·0, 41·4, 38·6 (s.e., 0·37) and 33·8, 34·1, 34·2 (s.e., 0·42). Ensiled mixtures of malt distillers’ grains and molassed sugar beet pellets can be used to replace some of the conventional concentrates or grass silage for dairy cows giving moderate yields without a loss of production.

Provision of a balanced supply of fermentable metabolisable energy (FME) and effective rumen degradable protein to rumen microbes enables maximum utilisation of energy and protein in dairy cow diets. Cane molasses containing a high proportion of water soluble carbohydrates can be very effective source of FME in dairy cow diets. The objective of this experiment was to evaluate the effect of the inclusion of molasses and fishmeal in the concentrate component of the diet, on the performance of lactating dairy cows.

Provision of a balanced supply of fermentable metabolisable energy (FME) and effective rumen degradable protein to rumen microbes enables maximum utilisation of energy and protein in dairy cow diets. Cane molasses containing a high proportion of water soluble carbohydrates can be very effective source of FME in dairy cow diets. The objective of this experiment was to evaluate the effect of the inclusion of molasses and fishmeal in the concentrate component of the diet, on the performance of lactating dairy cows.