Many producers have been encouraged by high cattle prices and better grass to replenish their breeding herds. But they need to keep in mind that the replacement heifer needs to have a higher plane of nutrition available to her than does the older cow. “One of the hardest calves to breed for is that second calf,” Dr. Robert Wells, livestock consultant with the Samuel R. Noble Foundation in Ardmore, Okla., told Ozarks Farm & Neighbor, “and typically what we see is that first calf female is not in a high enough condition to support all of the bodily functions of maintenance, growth, lactation, and then finally reproduction. So we want to see her body condition score in at least a 6 at calving, and preferably a 5 1/2 or greater at rebreed time.”
To achieve that, ensure replacement females have some of the better pasture available to them; winter pasture, both annuals and perennials, will typically be of a higher nutritional value. If their needs can’t be met solely through pasture, supplemental feed will be needed – but not too much. “A couple pounds of additional feed per day may be all that it takes to keep her on a positive plane of nutrition,” Wells said. “One of the old rules of thumb that people used to use was to feed replacements a lot of corn. My philosophy is we can use corn if it is economical, but you want to stay less than 5 pounds per head per day in that scenario.”
Dr. Patrick Davis, University of Missouri livestock specialist at the Cedar County office in Stockton, forwarded charts (Table 1 & Table 2) prepared for articles written by Georgia Cooperative Extension researchers. He told OFN, “A heifer has similar nutritional requirements to a lactating cow. However, based on the two tables, pregnant, non-lactating mature cows have lower protein requirement than developing heifers.”
Table 1 shows that as Average Daily Gain increases on the developing heifers, the level of Total Digestible Nutrients (TDN) in the diet increases to a higher level than those of both lactating and non-lactating pregnant cows. “An obvious difference between mature cows and heifers is body size, which is a major determinant of feed intake,” Davis noted. “Therefore, feed intake is higher for mature non-lactating pregnant and lactating cows than for developing heifers.” The calcium/phosphorus (Ca/P) ratio requirement for all three classes is 2:1; however, Davis said the first calf cow has the highest nutrient requirement, since she is lactating, trying to repair her reproductive tract/breed back, and continuing to grow.
The Georgia researchers recommended hay be tested for nutrient content prior to feeding to ensure supplementation is adequate. They said, “Hay intake should be 1.75 to 2 percent of body weight when the heifer is fed grain at 1 percent of her body weight. If hay intake is lower than the recommended level, then hay quality is likely poor.” In addition to the winter annuals for spring born heifers, they noted, “Fall-born heifers are weaned in the spring and will spend a portion of the development period on summer forages.” They said heifers will usually gain about 1 pound per day grazing bermudagrass, but this can vary considerably with variety, forage availability and time of year.
And Wells stressed the importance of the heifers making their target weights. He said, “At breeding time we want those females to be about 65 percent of mature weight, and then at calving we want them to be about 85 percent of mature weight, or heavier. We just don’t want that female being bred too small because, one, the likelihood of her getting bred is lower, and then number two she’s going to have a lot of room to have to catch up so that she’s big enough to calve unassisted, and then to be able to supply enough milk for that calf – and get rebred for that second calf.”
