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Short Communication: Effect of Postgrazing Residual Pasture Height on Milk Production


Lee, JM and Donaghy, DJ and Roche, JR, Short Communication: Effect of Postgrazing Residual Pasture Height on Milk Production, Journal of Dairy Science, 91, (11) pp. 4307-4311. ISSN 0022-0302 (2008) [Refereed Article]

DOI: doi:10.3168/jds.2008-1188


In grazing systems, dry matter intake (DMI) and milk production have been reported to increase with increasing pasture allowance (PA). This has often led to greater postgrazing residual heights being associated with a well-fed cow. However, in previous studies pastures were often managed to be homogeneous pretreatment, confounding the effect of postgrazing height and PA because high PA led to high postgrazing height. The objective of this study was to determine whether postgrazing height affects milk production if cows are offered the same PA. Before the study, perennial ryegrass (Lolium perenne L.) dominant pastures were randomly allocated to 1 of 3 grazing treatments and defoliated to 4.1 ± 0.3 (low), 5.1 ± 0.3 (medium), or 5.9 ± 0.3 (high) cm compressed postgrazing residual pasture height. When a minimum of 2 new leaves had emerged on the majority of ryegrass tillers, 30 multiparous dairy cows were randomly assigned to 1 of the 3 treatments and grazed their respective pastures over a 10-d period. Cows were offered a similar PA above the preexperimental postgrazing residual (17.1 ± 2.9 kg of dry matter/cow per d). Pasture disappearance per daily grazing area (estimated DMI) was similar across treatments (14.8 kg of dry matter/cow per d). Milk yield was negatively correlated with postgrazing height, but postgrazing height had no effect on milk component yield. Although the reason for this reduction in milk yield remains unclear, data indicate that low postgrazing heights do not adversely affect milk production. © American Dairy Science Association, 2008.

Item Details

Item Type:Refereed Article
Research Division:Agricultural, Veterinary and Food Sciences
Research Group:Crop and pasture production
Research Field:Agronomy
Objective Division:Animal Production and Animal Primary Products
Objective Group:Pasture, browse and fodder crops
Objective Field:Sown pastures (excl. lucerne)
UTAS Author:Lee, JM (Mr Jenn Ming Lee)
UTAS Author:Donaghy, DJ (Associate Professor Danny Donaghy)
UTAS Author:Roche, JR (Dr John Roche)
ID Code:59057
Year Published:2008
Web of Science® Times Cited:14
Deposited By:Agricultural Science
Deposited On:2009-11-17
Last Modified:2009-11-17

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