Short term fasting as a tool to design effective grazing strategies for lactating dairy cattle: a review

Abstract

Varying the time since the last meal (i.e. fasting) is a means of manipulating foraging behaviour. Management practices that restrict grazing time, and/or change the timing of the grazing session, may be analogous to changes introduced with different fasting regimes, suggesting that the same pattern of responses on foraging behaviour could be expected. Concepts related to eating patterns of grazing dairy cows are briefly reviewed, and impacts of short-term (i.e. within day) fasts on ingestive behaviours are discussed. Finally, several experiments that examined impacts of short-term fasts on eating patterns, ingestive behaviours and performance of lactating dairy cows are reviewed. Management practices that create shorter grazing sessions (i.e. longer fasting periods before grazing), and/or involve afternoon grazing, result in longer initial grazing bouts, higher intake rates, reductions in rumination time during the grazing session, as well as more pronounced changes in rumen pH, concentrations of rumen fermentation metabolites and rumen load. All of these changes have been associated with improvements in performance of grazing dairy cattle. These concepts and findings have implications in defining optimal grazing strategies, as well as allowing cattle performance, sward conditions and nutrient balances to be predicted and analysed in an integrated manner.

Animal behavior and pasture depletion in a pasture-based automatic milking system

“…The opposite occurred for PRE cows. These findings support the idea that after a period of fasting, rumination can be postponed in favor of grazing (Kennedy et al, 2009) and that rumination bouts tend to occur 1 to 2 h after the start of grazing (Chilibroste et al, 2007;Gregorini et al, 2012). Furthermore, rumination in sheep was not found to be a synchronized activity (Rook and Penning, 1991), which could suggest that animals can decide to engage in rumination on an individual basis.…”

“…Research conducted by Gregorini et al (2009) andChilibroste et al (2007) described the potential use of a fasting period in dairy cows, as a means to increase subsequent grazing behavior. The latter author suggested the possibility of using time since last meal as a means of inducing feeding motivation, which could be the case of PRE cows in this study.…”

“…Studies conducted in conventional pasture-based systems have analyzed the impact of supplementation (Phillips and Leaver, 1986;Sheahan et al, 2011), frequency of pasture allocation (Dalley et al, 2001;Granzin, 2003), pasture height (Gibb et al, 1997) and pasture allowance (Chilibroste et al, 2012), together with available grazing time (Gregorini et al, 2009;Kennedy et al, 2009;Perez-Ramirez et al, 2009), prior fasting (Chilibroste et al, 1997 and2007) and time of the day (Gregorini, 2012) on cow behavior.…”

Managing variations in dairy cow nutrient supply under grazing

“…The conditions of the simulations are described in Table 3. or manure management. In practice, daily access time at pasture could also be used as a grazing management tool if a time constraint would allow increasing grazing efficiency through manipulation of foraging behaviour (Chilibroste et al, 2007). If short-term behavioural adaptation following feed deprivation is well known (Chilibroste et al, 2007), the extent to which time availability affects dairy cow performance and intake, as well as behavioural adaptation mechanisms have been recently studied in various situations at daily scale.…”

“…In practice, daily access time at pasture could also be used as a grazing management tool if a time constraint would allow increasing grazing efficiency through manipulation of foraging behaviour (Chilibroste et al, 2007). If short-term behavioural adaptation following feed deprivation is well known (Chilibroste et al, 2007), the extent to which time availability affects dairy cow performance and intake, as well as behavioural adaptation mechanisms have been recently studied in various situations at daily scale. In recent studies, it has been reported that, with lowto-medium supplementation levels, MY is generally reduced when daily time at pasture, given in one grazing session daily, is ,8 h (Kristensen et al, 2007;Delaby et al, 2008).…”