Dry matter intake and energy balance in the transition period.

It is easy, based on theoretic considerations, to make the argument that maximizing DMI is important to minimize postpartum complications and losses in milk production that may be associated with them. However, research over the past several years provides ample evidence that successful "passage" through the periparturient period is more complicated than simply maximizing feed intake. Anecdotal evidence from veterinarians and nutrition consultants also confirm that feeding low-NDF diets to achieve high prepartum feed intakes during the prefresh transition period does not necessarily solve fresh-cow problems. Perhaps more important than maximizing feed intake is to minimize the likelihood of cows experiencing large drops in feed intake immediately before parturition. Retrospective analysis of existing data sets indicates that this hypothesis has merit; research must be conducted to vigorously test it. Until then, it seems reasonable to try to achieve high DMI, if it can be sustained through parturition. If it cannot, perhaps a more conservative approach is to limit voluntary intake by increasing dietary fiber, because data suggests that cows fed in such a manner experience less dramatic decreases in feed intake as parturition approaches. We examined the importance of parity, body condition score, and various diet components that may influence DMI during the final 3 weeks before parturition, but they only explained 18% of the variation in intake among cows. Clearly, there are many other factors that affect intake that need to be identified. Aspects of farm management that may influence animal stress need to be investigated, particularly during the prefresh transition period when cows are inherently prone to reductions in feed intake.