Spring calved, pasture grazing lactating dairy cows (N = 54) used in the study were a subset of the whole herd (N = ~260), they grazed together along with the other cows and altogether managed as one herd. The selection of cows was based on their breed type and lactation number within each breed and breeding worth (BW) index value. BW index value is the measure of the genetic merit of the animal for farm profit (Gregorini et al., 2013 (link)). Eighteen (N =18) cows from each of the three breeds, Holstein-Friesian, Jersey, and Holstein-Friesian/Jersey Crossbreed (KiwiCross) were included in the group. The cows included in each breed group were from different lactations (1st, 2nd, and 3rd) with six cows (N = 6) from each lactation. The cows within each lactation had varying BW index values (103 < BW > 151). The cows were altogether kept in the same grazing paddocks all the time throughout their lactation period (~270 d) except when brought to the milking shed (~ 2 h per milking) at 0500 hours. All cows from different breeds and in different lactations grazed the same pasture at the same time.
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