– Ed Vollborn, Dr. Tom Turner, Jeff Fisher and Gene Balthaser; OSU Extension
The focus of a study at the Jackson Branch of the Ohio Agricultural Research and Development Center in southern Ohio has been to “establish” an expected gain and body condition score increase for gestating beef cows utilizing low cost forage stockpile. Critics of extended and year-round grazing systems have often promoted a perception of poor animal performance. Research dating back 30 years or more by Dr. Roy Blaser, at Virginia Tech, documented the dynamic relationship of respiration and photosynthesis in forage plants. During the fall stockpile period with bright sunny days (high photosynthesis) and relatively cool temperatures (low respiration) an energy dense forage is produced. Three years of Ohio work has documented superior animal performance from this high quality fall produced forage.
A three year average gain of 1.67 pounds per day was attained on 125 spring calving (March 1) cows during the October, November, December grazing period. That gain has been very predictable with 1.65 pounds in 1994, 1.64 pounds in 1997, and 1.71 pounds in 1998. Body condition scoring (BCS) utilized the Ohio 1-9 system with 1 being emaciated and 9 being very fat. During the fall period, a shift to higher scores took place. The three year average fall increase in BCS was .64. Of critical importance was the number of cows that moved from BCS 4 (borderline) to BCS 5 (moderate) or above. For example, in 1998, more than 80% of the cows starting out with a BCS of 4 increased their BCS to 5 or higher by late December.
Cows in borderline condition at weaning need to gain 180 pounds before calving (Wiltbank 1982). This would be the combined increase from fetus and body condition. Cows in good condition are more tolerant to the stresses of winter and require less maintenance energy per unit of weight than do cows in poor condition. Producers serious about managed fall grazing can put on that gain prior to January 1.
Cows used for the study are also a part of on-going research conducted by Dr. Mike Day and Dr. Tom Turner. The cows grazed a mixed sward of tall fescue, orchardgrass, Kentucky bluegrass and clover. Length of stockpile varied from 30-140 days. A random tall fescue sample revealed a 26% endophyte infection with no pasture having more than 50% fescue in the stand. During the term of the study 1996-1998, December cow weight rose an average 80 pounds per cow despite selection efforts to reduce frame size. Literature suggests that it takes 75-80 pounds of gain to raise body condition score one point. It took an average 145 pounds to earn a one point increase in BCS in this study. Traditional numbers may be too conservative for the size and type cows found in well managed herds today.
In conclusion, significant weight gain can be accomplished at a minimal cost during the fall grazing period. Minimal fetal development for spring calving cows, energy dense forage and favorable environmental conditions make fall and early winter a natural time to put cows in good condition.