Australia is the world’s leading source of lupin grain, producing ~1 million tonnes annually, of which 30% is used by the domestic livestock industry and the rest is exported for use in animal diets, including dairy cows. The domestic dairy industry uses ~70 000 tonnes annually, mainly as a supplementary feed source in pasture-based systems. Although much published information exists on the nutritive value of lupins for dairy cows, it tends to be fragmented and, in some important instances, exists only in the form of reports or publications outside the mainstream scientific journals. This paper aims to present a critical assessment of the current knowledge regarding the nutritional value of lupins as a feed for dairy cows, and offers recommendations for future research. For cows grazing pasture or fed diets based on conserved pasture or cereal hay, the mean fractional response to lupin feeding was 0.53 kg milk/kg DM lupins, with a range of 0–0.97 kg/kg. The mean fractional forage substitution rate was 0.54 kg DM/kg lupins, and this appeared to be independent of the type of basal forage. In experiments using cows fed iso-nitrogenous and iso-energetic total mixed rations, substituting oilseed protein such as soybean meal with cracked lupin grain had no significant effects on yield of milk, fat, and protein, but it reduced milk protein concentration and had mixed effects on fat concentration. There were no significant differences in milk yield or in fat or protein concentration when lupins were substituted for other pulse grains such as faba beans or peas. Treatment of lupin grain with heat or formaldehyde reduced lupin protein degradability in the rumen, but was not shown to have consistent benefits over untreated lupins in terms of increased milk yield. Substitution of cereal grains with an equivalent weight of lupins in dairy concentrate rations generally resulted in increased yield of milk, fat, and protein, and a higher fat concentration. The higher yield responses in most cases could be explained on the basis of the higher metabolisable energy content of lupins compared with cereal grains, although the contribution from a potentially lower incidence of rumen lactic acidosis could not be discounted. Feeding Lupinus albus lupins to cows significantly increased the concentration of C18 : 1 in milk and reduced that of C12 : 0–C16 : 0, thus shifting the fatty acid profile of milk towards national dietary guidelines for improved cardiovascular health in human populations. Although the review lists some recommendations for improving the nutritive value of lupins, current commercially available cultivars possess characteristics that make them attractive as a feedstuff for dairy cows.

Milk fat whiteness is the key to the uniqueness of Western Australian milk. Following a controlled feeding regime, milk was collected fortnightly for 6 mo from 2 treatment groups: dryland and irrigation. The results showed that it was possible to produce high-quality milk with whiter fat by a controlled feeding regime and diet while maintaining the health of Holstein-Friesian cows. The reflectance method using infinite optical thickness showed milk fat color differences due to feed could be measured. After 8 wk of the study, milk fat from the dryland treatment was significantly whiter (P < 0.05) than the irrigation treatment with area under curve total reflectance of 902.8 and 838.3, respectively. The official Japanese industry method, Agriculture and Livestock Industries Corp. (ALIC) butter tone, showed that from the 2nd to the 5th collections the color of milk fat from cows fed silage and grain (dryland treatment) was significantly whiter (P < 0.01) with an average butter tone of 0.15 absorbance per gram compared to cows fed green pasture and grain (irrigation treatment) with a butter tone of 0.21 absorbance per gram. Protein and riboflavin levels also affect the whiteness of milk. The study followed the main feeding protocol of dryland dairies and suggests the majority of milk from Western Australia would receive a grade 1 classification, as dryland dairies dominate supply.