Diurnal shifts in nutritive value of alfalfa harvested as hay and evaluated by animal intake and digestion

Burns, J.C. and Fisher, D.S. and Mayland, H.F. (2007) Diurnal shifts in nutritive value of alfalfa harvested as hay and evaluated by animal intake and digestion. Crop Science. 47:2190-2197.

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Abstract

Forages accumulate nonstructural carbohydrates
during the day, with animals showing
preference and improved daily responses from
afternoon compared with morning cut hays. This
study evaluated alfalfa (Medicago sativa L.) hay
harvested at 0700, 1000, 1300, 1600, and 1900
h to determine how nutritive value changes during
the day and to assess the impact of these
changes on animal preference using cattle (Bos
taurus L.), sheep (Ovis aries L.), and goat (Capra
hircus L.) responses. Total nonstructural carbohydrates
were altered by time of cut (cubic contrast,
P < 0.01) ranging from 85 g kg−1 at 0700 h
to 83 g kg−1 at 1000 h, then increasing to 97 g
kg−1 by 1600 h with little change at 1900 h (96 g
kg−1). Fiber fractions also varied diurnally, with a
quadratic decrease from 418 g kg−1 at 0700 h to
387 g kg−1 by 1900 h in neutral detergent fiber. A
combined analysis of three animal trials showed
a linear increase in dry matter intake (DMI) with
later hay harvest, a cubic response for dry matter
digestion (DMD), and a linear increase in
digestible DMI. Mean DMI increased from 27.5
g kg−1 body weight at 0700 h to a maximum
of 30.8 g kg−1 body weight at 1600 h, whereas
DMD decreased from 658 g kg−1 at 0700 to 647
g kg−1 at 1300 h and peaked at 664 g kg−1 at
1600 h. Digestible DMI increased from 18.1 g
kg−1 body weight at 0700 h to a maximum of
20.5 g kg−1 body weight at 1600 h. No additional
advantages in animal responses were noted by
cutting after 1600 h.

Item Type:	Article
NWISRL Publication Number:	1234
Subjects:	Animal Irrigated crops > Alfalfa > Time-of-day harvest difference Mass Import - autoclassified (may be erroneous)
Depositing User:	Dan Stieneke
Date Deposited:	20 Nov 2010 21:49
Last Modified:	31 Oct 2016 16:43
Item ID:	69
URI:	https://eprints.nwisrl.ars.usda.gov/id/eprint/69