Heifers that calve early may be set for life
April 16, 2012
Setting a replacement heifer up for life can have significant economic benefits for beef producers. Heifers that breed early, and have trouble-free calving are more likely to breed back early for the rest of their lives, according to Larry Rowden, a district sales manager with ABS Global, Inc.
“The earlier cows calve within the calving season, the more profitable they will be to that operation,” Rowden said. “Synchronizing heifers to get pregnant early in the breeding season can have benefits that will last the lifetime of that heifer.”
Rowden referred to a study looking at the value of feeder steers based on when they were born within the calving season. “The study indicated that the most revenue came from steers who were born during the first 21 days of the calving season,” he explained. A study of the heifer mates also found that the earlier they were born during the calving season, the more likely they were to be cycling going into breeding season. “The study also concluded that a higher percentage were bred and pregnant early in the breeding season, if they were born the first 21 days of the calving season themselves,” he said.
Producers may want to consider growing and developing the heifers with resources similar to the ones they will experience when they become a cow. “I think it is important to allow them to graze at some point during the development phase, whether it is on grass, cornstalks, or hay meadows,” he said. “It will make them better cows that are more adapted to the environment they live in,” he said. “They will learn how to graze and take care of themselves.”
Rowden said producers need to make sure their heifers are in a body condition score (BCS) of five to six, and gaining weight going into breeding season. “If heifers are above a BCS 6, they are likely carrying too much condition and the results may not be as good,” he said.
It is also important the heifers are on a balanced ration prior to breeding, whether on green grass or a fed ration. “The key is not to overdo any of the nutrients,” he explained. “Don’t overdo the protein,” he cautioned. “A diet of straight alfalfa may also be too much for a growing heifer. I would recommend a mixture of alfalfa and grass,” he added. The key is to have the heifers on an upward plane of nutrition going into breeding without getting fat.
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Rowden encourages producers to consider using synchronization protocols to group the heifers up into an earlier and tighter calving interval. “There are three categories of synchronization protocols – heat detection, heat detection with timed AI, and fixed time AI,” he explained. “The difference between these protocols is dependent upon the amount of time a producer wants to spend with his cattle. When we talk to a rancher about synchronization, we determine what kind of labor and time resources he has and what his goals are with a synchronization program to help us determine which system to recommend,” Rowden said.
If a producer chooses heat detection with timed AI or fixed time AI, he can expect 50-60 percent of the heifers to be bred within a one to three day period, depending upon which protocol he chooses. “For heifers that are bred in one day, we can expect them to calve over a two to three week period,” Rowden said. “Those heifers that we didn’t get pregnant will recycle over an eight to 10 day period because of the variation in the length of the estrus cycle,” he added.
Rowden encourages producers to breed the replacement heifers for a short period of time. “I recommend giving them two chances to become pregnant,” he said. “That can help a producer shorten up the calving season of the whole herd, and give the heifers the opportunity to breed early in the season.” With synchronization and AI, heifers can be limited to a 30 day breeding season, which includes natural service for an additional cycle.
Rowden said at breeding, beef producers need to pay careful attention to moving the heifers. “The best time to move heifers is soon after synchronization and AI – usually within the first five days,” he said. “Once the heifers have ovulated and fertilization has occurred, it takes about five days for the corpus luteum to develop on the ovary, so any stress that occurs within those five days is not likely to cause problems in terms of affecting pregnancy rates,” Rowden explained. “The critical time is eight to 15 days after AI, when a heifer learns she is becoming pregnant. If heifers are stressed at that time, it can have a detrimental affect on pregnancy rates,” he added.