By Donald Stotts, Oklahoma State University Extension
Cattle producers with access to adequate wheat pasture in late November and early December can use it as a supplement for pregnant replacement heifers.
Pregnant heifers consuming full feed on wheat pasture will gain about 3 lb. per head per day. However, it is important that wheat pasture be used judiciously.
"A pregnant heifer that is on wheat too long can become very fat and, in turn, potentially experience calving difficulties," says Glenn Selk, Oklahoma State University Cooperative Extension emeritus cattle specialist. "Also, the wheat pasture can be used for gain of stocker cattle or weaned replacement heifers more efficiently."
In the early 1990s, a two-year OSU study was conducted with bred replacement heifers on three different wintering diets:
- Group 1 heifers were placed on wheat pasture full-time from the first week of December until the first week of February;
- Group 2 heifers were given access to a self-feeder with a growing ration that was developed to mimic the growth of the wheat pasture heifers; and
- Group 3 heifers were wintered on native range and fed 3 lb. per day of 40% protein cube.
At the beginning of calving on Feb. 7 and until spring, all heifers were placed on native range and fed the 40% protein supplement. Birth weights were similar for all groups of heifers.
"In the first year, when nearly half of the Group 1 heifers were in a body condition score 7, more calf loss was noted in this group compared to the others," Selk says.
Some heifers were noted to experience apparent uterine fatigue, a condition where, during labor, the heifer strains for a short time, then gives up.
"If wheat pasture is used for bred heifers, use it as a protein supplement by allowing the heifers access to the wheat pasture on at least alternate days," Selk says. "Some producers report that one day on wheat pasture and two days on native range or bermudagrass pasture will work better. This encourages the heifers to go rustle in the warm season pasture for the second day, rather than just stand by the gate waiting to be turned back in to the wheat."
It is important to note that an adequate amount of standing forage or dry hay must be available during the "off" days.
Selk says that whatever method is used to grow the pregnant replacement heifers, producers should plan to have them in at least body condition score 6 by calving so that they will grow into fully developed, productive cows.