The delivery of fresh feed is clearly an important factor in stimulating cows to eat. Thus, increased frequency of feed delivery can greatly influence feeding behaviour patterns, and thus also affect cow health and productivity. When cows are offered feed only once daily, there are significant peaks in feeding activity in the immediate time period following feed delivery compared to 2x feeding (DeVries et al., 2005). This behavioural response elicited by the delivery of fresh feed provided 1x daily could result in slug feeding and predispose cows to sub-acute ruminal acidosis (SARA) (DeVries et al., 2005) due to large diurnal fluctuations in ruminal pH (Shabi et al., 1999). Inversely, cows fed more frequently (4x and 5x daily) tend to consume feed more evenly after each feed delivery, increasing their feeding time throughout the day (DeVries et al., 2005; Mantysaari et al., 2006). Added to that, DeVries et al. (2005) found that subordinate cows were not displaced as frequently when fed more often, indicating that these cows would have greater access to feed, particularly fresh feed, when the frequency of feed delivery is high. Further, providing feed 2x/d or more often has also been demonstrated to reduce the amount of feed sorting as compared to feeding 1x/d (DeVries et al., 2005; Endres and Espejo, 2010; Sova et al., 2013), which would further contribute to more consistent nutrient intakes over the course of the day. Thus, such desirable feeding patterns are conducive to more consistent rumen pH (French and Kennelly, 1990), which likely contributes to improved milk fat (Rottman et al., 2011); fiber digestibility (Dhiman et al., 2002), and possibly production efficiency (Mantysaari et al., 2006) observed when cows are fed more frequently than 1x/d. Interestingly, in a recent field study of free-stall herds in Eastern Ontario, feed delivery of 2x/d compared to 1x/d has been demonstrated to be associated with less feed sorting, greater feed intake (+1.4 kg/d), and greater milk yield (+2.0 kg/d) (Sova et al., 2013).
When fed a TMR, dairy cows have a natural tendency to continually sort through the feed and toss it forward where it is no longer within reach. This is particularly problematic when feed is delivered via a feed alley and, thus, producers commonly push the feed closer to the cows in between feedings to ensure that cows have continuous feed access. Research suggests that feed push-up does not have the same stimulatory impact on feeding activity as does fresh feed delivery (DeVries et al., 2003); nonetheless, push up does play a vital role in ensuring that feed is accessible when cows want to eat.
There is evidence to suggest that the timing of feed delivery is also important for lactating dairy cows. Availability of fresh feed following the return from milking has typically been used to encourage cows to remain standing (while feeding) rather than to lie down. Researchers have shown that the presence of fresh feed in the bunk encourages longer post-milking standing times (DeVries and von Keyserlingk, 2005). DeVries et al. (2010) recently found that the provision of feed around milking time resulted in the longest post-milking standing times. Further, this was the first study to document how post-milking standing time relates to the risk of intramammary infection; cows that lay down, on average, for the first time 40 to 60 min after milking tended to have lower odds of a new intramammary infection caused by environmental bacteria compared to cows that lay down within 40 min after milking. These results suggest that management practices that discourage cows from lying down immediately after milking, such as providing fresh feed frequently through the day (near the time of milking) may help decrease the risk of intramammary infection. For robotic milked cows, which milk frequently throughout the day, ensuring continual access to feed in the bunk, via frequent fresh feed delivery as well as feed push up is important to promote standing time after milking and reduce the risk of intramammary infection (DeVries et al., 2011b)