Cattle, sheep, and goats, prefer forage cut in
the afternoon to that cut in the morning. This preference has
been attributed to the presence of more sugar in the afternoon
than morning forage. However, no quantitative studies have
been reported for horse responses. We chose to test horses'
preference for afternoon (PM) vs. morning (AM) cut alfalfa-grass
hay grown in southeastern Montana. Mixed alfalfa-grass
(alfalfa = 15 % bloom) was cut on 5 July 2002 at 1900
hr and again the next morning at 0700 hr using a swather with
conditioner. Hay was air dried for 24 h and baled into 300 kg
round bales. Bales were placed on palettes, tarped, and
stored in a metal hay shed. Hay consisted of 70% Grimm
alfalfa and 30% Fairway crested wheatgrass. Five kg of both
hays (AM- and PM - cut) were offered ad libitum to each of
five American Quarter horses for 10 minutes during the
morning and afternoon. Both feeding order and position of
feed buckets were randomized at each feeding. Dry matter
intake was determined by weighing before and after feeding.
Four samples of each bale were dried in a convection oven
(60° C) and ground into a fine powder. One gram of
powdered hay was combined with nine milliliters of distilled
water, boiled for five minutes, and vacuum filtered through
Whatman #1 qualitative paper. Sugars in the filtrate were
determined using a hand held Bausch and Lomb 400SD
refractometer having range of 0 - 60% . Data were tested with
analysis of variance. Horses preferred the PM-cut hay by
eating twice as much of the PM - as of the AM -cut hay (P =
0.001). The sugar concentration was 170 mg/g greater in the
extract from the PM -cut than from AM-cut hay (P = 0.04).
Horses are able to identify forage having greater sugar
concentrations and will eat larger quantities of this hay
