Lactation potential as a criterion for strategy of feeding total mixed rations to dairy cows

A trial was conducted from freshening to 30 wk postpartum to evaluate assignment of cows into production potential groups based on early lactation performance to optimize the time for switching from high to medium nutrient concentration TMR. Cows received a TMR formulated for early lactation until wk 4 of lactation and a high nutrient concentration TMR until 13, 19, or 25; the high TMR was followed by a medium nutrient concentration TMR until the end of the trial. Cows were assigned to high, medium, or low potential groups separately for parities 1, 2, and > or = 3 based on daily 3.5% FCM production as a percentage of BW measured during wk 6 and 7 of lactation. Low potential cows tended to partition energy intake into BW gain earlier in lactation than medium and high potential cows. For low potential cows, an early transfer to medium TMR moderated BW gain with no negative effect on production. High potential cows maintained their BW on the high ration; however, early transfer negatively affected production. Classification of individual cows into potential groups based on early lactation performance can serve as a useful tool for TMR feeding strategy later in lactation.