• Forages cut in afternoon, vs morning often contain more soluble sugars and are preferred by cattle, sheep, and goats (Fisher et al. 1999).
  
• In a qualitative study, horses were able to recognize a difference between afternoon and morning cut alfalfa (Mayland et al., 2001).
  
• This study quantitatively determined horse preference for an alfalfa-grass hay cut in the afternoon versus that cut in the morning (Consortium, 1988).

METHODS AND MATERIALS

• The study was conducted near Baker in SE Montana.
  
• Hay was 30% Fairway crested wheatgrass and 70% Grimm alfalfa at 15% flower stage.
  
• Hay was cut on 5 July 2002 at 1900 hr and again the next morning at 0700 hr using a swather with conditioner.
  
• Hay was cut, dried for 24h, baled into round bales, and removed from the field under ideal conditions (Table 1).
  
• Bales were placed on pallets, tarped and stored in a hay shed.
  
• Hay cores were removed from each bale for dry matter and sugar analyses.
  
• Hay samples were dried (60° C) for two weeks and then ground to a fine powder. One gram samples were combined with 9 ml of distilled water and boiled for five minutes. This solution was vacuum filtered through #1 Whatman and sugars in filtrate determined using a handheld Bausch and Lomb 400SD refractometer having range of 0 - 60%.
  
• Five American Quarter Horses were used in this study. Three older horse were kept in one corral and the two younger horses were kept in a second corral. They were each fed about 20 kg/day locally produced hay.
  
• During test time, individual horses were offered 5 kg of each hay (PM-, and AM-cut) in identical buckets placed on the ground. Horses were allowed to eat for 10 minutes. The animals were given test hays twice daily for 4 consecutive days. Feeding order and hay placement were randomized.
  
• Data were analyzed using Analysis of Variance (Systat, 1999).

RESULTS

• Horses consumed on average 0.63 kg of PM hay and only 0.31 kg of AM hay during each feeding
  (Table 2, P = .001).
  
• Horses, feeding times, and interactions were not significant (P> 0.20, see W.S. ASAS proceedings 2003).
  
• The hot water extracts of the PM-cut hay contained about 42% sugar while extracts from the AM-cut hay contained about 36% sucrose (Table 2). Sugar concentrations were significantly greater in the afternoon-cut hay than in the morning-cut hay.

DISCUSSION

• During the preference sessions, horses ate about twice as much of the PM- as of the AM-cut hay. Like ruminants, horses could easily distinguish between the afternoon and morning-cut hays. If energy is desired in the horse hay, then cutting the hay in the afternoon will boost the concentration of sugar present. (Fisher, et al. 1999, Mayland et al. 2001). However, horses have a tendency to over-eat and are often limit fed. Afternoon-cut hay for horses may not always be advisable unless they are limit fed.
  
• For grazing horses, especially the pony breeds, access to forages containing high concentrations of fructans (a soluble sugar) is thought by some (See: http://www.safergrass.org/ to increase the susceptibility to laminitis. We would be happy to hear your opinion on this possible relationship.
  
• As sugars accumulate in the actively growing forages, bright sunny days will enrich the sugar concentrations. This may be good or bad for horses.

Personal Vitae of Sr. Author

I recently graduated (2003) from Franklin High School in El Paso, TX. I was selected as Franklin All-Girl and was invited to give a speech for our graduation commencement exercises. I was the secretary for the Math Honors Society and competed in many science competitions in the southwest region. Last year, I was a finalist at the Intel International Science and Engineering Fair in Louisville, KY. This year, I was invited to the National Junior Science and Humanities Symposium in Colorado Springs, CO, to present my research. I enjoy riding horses, hiking and camping. I also work as a horseback riding instructor for Therapeutic Horsemanship of El Paso, an organization that specializes in hippotherapy for physically- and mentally-disabled students. My summers are spent on the family ranch in southeastern Montana, where I am able to ride to my heart's content. This is where I developed my love for the land and an interest in agriculture. I attended Montana Range Days for three years and was awarded first place this past summer. I became interested in PM-harvest of hay the summer before my sophomore year. I was brainstorming with a family friend who has been instrumental in catalyzing many young peoples' interests in agriculture, and she mentioned that she had access to a refractometer, which would measure the percent sucrose in a plant. Thus, I started my research and consulted with Dr. Hank Mayland, from Kimberly, ID, who has mentored and inspired me to continue answering my own questions for three years. My future plans include obtaining a double major in Range and Animal Science from New Mexico State University. I would like to continue doing research and see where my heart and opportunities lead me.