Milk‐production potential of different sward types in a temperate southern Australian environment

Abstract

SummaryThe milk-production potential of different sward types was measured in each of the four seasons of the year in a replicated experiment in south-west Victoria, Australia. Dairy cows were offered ad libitum allowances of a 'short-term winter' sward, based on Italian ryegrass (treatment STW), a 'long-term winter' sward, based on a winter-active tall fescue (treatment LTW), a 'longterm summer' sward, based on a summer-active tall fescue (treatment LTS) and a Control sward (perennial ryegrass) in four seasons (days in milk in parentheses): spring (November dairy cows, 124), summer (February, 227), autumn (May, 234) and winter (August, sixtyfour). A 'short-term summer' sward, based on chicory and white clover (treatment STS), was also included in summer. There was a significant season · treatment interaction caused by a more gradual decline in milk yield from peak for cows grazing treatment LTS compared to the Control treatment in the transition period from spring to summer. In summer, cows grazing treatment STS produced more milk (1AE41 kg fat plus protein per cow d ) than cows grazing all other treatments (0AE92 kg per cow d )1 ) because of the superior nutritive value of herbage of pre-grazing pasture and higher apparent dry-matter intakes. Swards based on alternative species to perennial ryegrass are capable of supporting milk production that is at least comparable over an annual cycle.

Pasture intake and milk production of dairy cows rotationally grazing on multi-species swards

“…In our experiment, the positive effect of the presence of chicory on pasture DM intake suggests that the negative effect of chicory's low DM concentration is largely compensated by the positive effect of the low NDF concentration or any other component on daily intake. This is in line with several previous studies, where intake and/or milk production have been found to increase when chicory was included in mixed pastures and fed to dairy cows, either at grazing (Chapman et al, 2008;Totty et al, 2013) or indoors (Barry, 1998;Minnee et al, 2012). The increase in milk production after inclusion of chicory in the diet generally ranges from 1 to 2 kg/day, but an increase in milk production as high as 6 kg/day has been observed for cows grazing clover-chicory mixtures in summer when compared with low-quality grass-based pastures (Chapman et al, 2008).…”

“…This is in line with several previous studies, where intake and/or milk production have been found to increase when chicory was included in mixed pastures and fed to dairy cows, either at grazing (Chapman et al, 2008;Totty et al, 2013) or indoors (Barry, 1998;Minnee et al, 2012). The increase in milk production after inclusion of chicory in the diet generally ranges from 1 to 2 kg/day, but an increase in milk production as high as 6 kg/day has been observed for cows grazing clover-chicory mixtures in summer when compared with low-quality grass-based pastures (Chapman et al, 2008). Advantages of MSS on milk production and milk solids production were clearly due to the cumulative effect of improved pasture chemical composition and higher pasture DM intake.…”

“…Grazing pure tall fescue generally had no effect, or else decreased milk production in dairy cows by 1 or 2 kg/day when compared with pure perennial ryegrass (Lowe et al, 1999), due to greater fibre concentration and lower digestibility, pasture DM intake being only slightly affected (INRA, 2007). There is evidence that replacing 10% of DM diet from ryegrass to fescue would only have small effects on cow nutrition, which is in line with the results of Chapman et al (2008) in mixed swards. Greater effects would be expected with older swards as tall fescue is well known for its relatively low rate of establishment compared with other grass species.…”

“…Under grazing management, the effect of including chicory in mixed swards on dairy cow performance is unclear. Pasture DM intake and milk production were unaffected by inclusion of chicory in the studies of Soder et al (2006) and Muir et al (2014), but increases in milk production and pasture DM intake were found in the studies of Li and Kemp (2005) and Chapman et al (2008). In order to investigate the potential advantages of MSS, a 2-year study was conducted to test the hypothesis that increasing botanical complexity from 1 (grass) to 5 sward species (grasseslegumes-forb) would affect pasture chemical composition, pasture DM intake, milk production and milk solids production of grazing dairy cows.…”

“…There is a rising interest from scientists to examine the effect of MSS on pasture chemical composition and nutritive value, pasture DM intake (Deak et al, 2009;Sanderson, 2010) and milk production in grazing dairy cows (Sanderson et al, 2005;Soder et al, 2006;Chapman et al, 2008). Evidence from these studies suggests that the yield benefit mainly results from including drought-tolerant species (i.e.…”